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llvm-project/clang/lib/Sema/SemaOverload.cpp

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//===--- SemaOverload.cpp - C++ Overloading -------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file provides Sema routines for C++ overloading.
//
//===----------------------------------------------------------------------===//
#include "clang/AST/ASTContext.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DependenceFlags.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/TypeOrdering.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/DiagnosticOptions.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/Overload.h"
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/Template.h"
#include "clang/Sema/TemplateDeduction.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallString.h"
#include <algorithm>
#include <cstdlib>
using namespace clang;
using namespace sema;
using AllowedExplicit = Sema::AllowedExplicit;
static bool functionHasPassObjectSizeParams(const FunctionDecl *FD) {
return llvm::any_of(FD->parameters(), [](const ParmVarDecl *P) {
return P->hasAttr<PassObjectSizeAttr>();
});
}
/// A convenience routine for creating a decayed reference to a function.
static ExprResult
CreateFunctionRefExpr(Sema &S, FunctionDecl *Fn, NamedDecl *FoundDecl,
const Expr *Base, bool HadMultipleCandidates,
SourceLocation Loc = SourceLocation(),
const DeclarationNameLoc &LocInfo = DeclarationNameLoc()){
if (S.DiagnoseUseOfDecl(FoundDecl, Loc))
return ExprError();
// If FoundDecl is different from Fn (such as if one is a template
// and the other a specialization), make sure DiagnoseUseOfDecl is
// called on both.
// FIXME: This would be more comprehensively addressed by modifying
// DiagnoseUseOfDecl to accept both the FoundDecl and the decl
// being used.
if (FoundDecl != Fn && S.DiagnoseUseOfDecl(Fn, Loc))
return ExprError();
DeclRefExpr *DRE = new (S.Context)
DeclRefExpr(S.Context, Fn, false, Fn->getType(), VK_LValue, Loc, LocInfo);
if (HadMultipleCandidates)
DRE->setHadMultipleCandidates(true);
S.MarkDeclRefReferenced(DRE, Base);
if (auto *FPT = DRE->getType()->getAs<FunctionProtoType>()) {
if (isUnresolvedExceptionSpec(FPT->getExceptionSpecType())) {
S.ResolveExceptionSpec(Loc, FPT);
DRE->setType(Fn->getType());
}
}
return S.ImpCastExprToType(DRE, S.Context.getPointerType(DRE->getType()),
CK_FunctionToPointerDecay);
}
static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
bool InOverloadResolution,
StandardConversionSequence &SCS,
bool CStyle,
bool AllowObjCWritebackConversion);
static bool IsTransparentUnionStandardConversion(Sema &S, Expr* From,
QualType &ToType,
bool InOverloadResolution,
StandardConversionSequence &SCS,
bool CStyle);
static OverloadingResult
IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
UserDefinedConversionSequence& User,
OverloadCandidateSet& Conversions,
AllowedExplicit AllowExplicit,
bool AllowObjCConversionOnExplicit);
static ImplicitConversionSequence::CompareKind
CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
const StandardConversionSequence& SCS1,
const StandardConversionSequence& SCS2);
static ImplicitConversionSequence::CompareKind
CompareQualificationConversions(Sema &S,
const StandardConversionSequence& SCS1,
const StandardConversionSequence& SCS2);
static ImplicitConversionSequence::CompareKind
CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc,
const StandardConversionSequence& SCS1,
const StandardConversionSequence& SCS2);
/// GetConversionRank - Retrieve the implicit conversion rank
/// corresponding to the given implicit conversion kind.
ImplicitConversionRank clang::GetConversionRank(ImplicitConversionKind Kind) {
static const ImplicitConversionRank
Rank[(int)ICK_Num_Conversion_Kinds] = {
ICR_Exact_Match,
ICR_Exact_Match,
ICR_Exact_Match,
ICR_Exact_Match,
ICR_Exact_Match,
ICR_Exact_Match,
ICR_Promotion,
ICR_Promotion,
ICR_Promotion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_OCL_Scalar_Widening,
ICR_Complex_Real_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Writeback_Conversion,
ICR_Exact_Match, // NOTE(gbiv): This may not be completely right --
// it was omitted by the patch that added
// ICK_Zero_Event_Conversion
ICR_C_Conversion,
ICR_C_Conversion_Extension
};
return Rank[(int)Kind];
}
/// GetImplicitConversionName - Return the name of this kind of
/// implicit conversion.
static const char* GetImplicitConversionName(ImplicitConversionKind Kind) {
static const char* const Name[(int)ICK_Num_Conversion_Kinds] = {
"No conversion",
"Lvalue-to-rvalue",
"Array-to-pointer",
"Function-to-pointer",
"Function pointer conversion",
"Qualification",
"Integral promotion",
"Floating point promotion",
"Complex promotion",
"Integral conversion",
"Floating conversion",
"Complex conversion",
"Floating-integral conversion",
"Pointer conversion",
"Pointer-to-member conversion",
"Boolean conversion",
"Compatible-types conversion",
"Derived-to-base conversion",
"Vector conversion",
"SVE Vector conversion",
"Vector splat",
"Complex-real conversion",
"Block Pointer conversion",
"Transparent Union Conversion",
"Writeback conversion",
"OpenCL Zero Event Conversion",
"C specific type conversion",
"Incompatible pointer conversion"
};
return Name[Kind];
}
/// StandardConversionSequence - Set the standard conversion
/// sequence to the identity conversion.
void StandardConversionSequence::setAsIdentityConversion() {
First = ICK_Identity;
Second = ICK_Identity;
Third = ICK_Identity;
DeprecatedStringLiteralToCharPtr = false;
QualificationIncludesObjCLifetime = false;
ReferenceBinding = false;
DirectBinding = false;
IsLvalueReference = true;
BindsToFunctionLvalue = false;
BindsToRvalue = false;
BindsImplicitObjectArgumentWithoutRefQualifier = false;
ObjCLifetimeConversionBinding = false;
CopyConstructor = nullptr;
}
/// getRank - Retrieve the rank of this standard conversion sequence
/// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the
/// implicit conversions.
ImplicitConversionRank StandardConversionSequence::getRank() const {
ImplicitConversionRank Rank = ICR_Exact_Match;
if (GetConversionRank(First) > Rank)
Rank = GetConversionRank(First);
if (GetConversionRank(Second) > Rank)
Rank = GetConversionRank(Second);
if (GetConversionRank(Third) > Rank)
Rank = GetConversionRank(Third);
return Rank;
}
/// isPointerConversionToBool - Determines whether this conversion is
/// a conversion of a pointer or pointer-to-member to bool. This is
/// used as part of the ranking of standard conversion sequences
/// (C++ 13.3.3.2p4).
bool StandardConversionSequence::isPointerConversionToBool() const {
// Note that FromType has not necessarily been transformed by the
// array-to-pointer or function-to-pointer implicit conversions, so
// check for their presence as well as checking whether FromType is
// a pointer.
if (getToType(1)->isBooleanType() &&
(getFromType()->isPointerType() ||
getFromType()->isMemberPointerType() ||
getFromType()->isObjCObjectPointerType() ||
getFromType()->isBlockPointerType() ||
First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer))
return true;
return false;
}
/// isPointerConversionToVoidPointer - Determines whether this
/// conversion is a conversion of a pointer to a void pointer. This is
/// used as part of the ranking of standard conversion sequences (C++
/// 13.3.3.2p4).
bool
StandardConversionSequence::
isPointerConversionToVoidPointer(ASTContext& Context) const {
QualType FromType = getFromType();
QualType ToType = getToType(1);
// Note that FromType has not necessarily been transformed by the
// array-to-pointer implicit conversion, so check for its presence
// and redo the conversion to get a pointer.
if (First == ICK_Array_To_Pointer)
FromType = Context.getArrayDecayedType(FromType);
if (Second == ICK_Pointer_Conversion && FromType->isAnyPointerType())
if (const PointerType* ToPtrType = ToType->getAs<PointerType>())
return ToPtrType->getPointeeType()->isVoidType();
return false;
}
/// Skip any implicit casts which could be either part of a narrowing conversion
/// or after one in an implicit conversion.
static const Expr *IgnoreNarrowingConversion(ASTContext &Ctx,
const Expr *Converted) {
// We can have cleanups wrapping the converted expression; these need to be
// preserved so that destructors run if necessary.
if (auto *EWC = dyn_cast<ExprWithCleanups>(Converted)) {
Expr *Inner =
const_cast<Expr *>(IgnoreNarrowingConversion(Ctx, EWC->getSubExpr()));
return ExprWithCleanups::Create(Ctx, Inner, EWC->cleanupsHaveSideEffects(),
EWC->getObjects());
}
while (auto *ICE = dyn_cast<ImplicitCastExpr>(Converted)) {
switch (ICE->getCastKind()) {
case CK_NoOp:
case CK_IntegralCast:
case CK_IntegralToBoolean:
case CK_IntegralToFloating:
case CK_BooleanToSignedIntegral:
case CK_FloatingToIntegral:
case CK_FloatingToBoolean:
case CK_FloatingCast:
Converted = ICE->getSubExpr();
continue;
default:
return Converted;
}
}
return Converted;
}
/// Check if this standard conversion sequence represents a narrowing
/// conversion, according to C++11 [dcl.init.list]p7.
///
/// \param Ctx The AST context.
/// \param Converted The result of applying this standard conversion sequence.
/// \param ConstantValue If this is an NK_Constant_Narrowing conversion, the
/// value of the expression prior to the narrowing conversion.
/// \param ConstantType If this is an NK_Constant_Narrowing conversion, the
/// type of the expression prior to the narrowing conversion.
/// \param IgnoreFloatToIntegralConversion If true type-narrowing conversions
/// from floating point types to integral types should be ignored.
NarrowingKind StandardConversionSequence::getNarrowingKind(
ASTContext &Ctx, const Expr *Converted, APValue &ConstantValue,
QualType &ConstantType, bool IgnoreFloatToIntegralConversion) const {
assert(Ctx.getLangOpts().CPlusPlus && "narrowing check outside C++");
// C++11 [dcl.init.list]p7:
// A narrowing conversion is an implicit conversion ...
QualType FromType = getToType(0);
QualType ToType = getToType(1);
// A conversion to an enumeration type is narrowing if the conversion to
// the underlying type is narrowing. This only arises for expressions of
// the form 'Enum{init}'.
if (auto *ET = ToType->getAs<EnumType>())
ToType = ET->getDecl()->getIntegerType();
switch (Second) {
// 'bool' is an integral type; dispatch to the right place to handle it.
case ICK_Boolean_Conversion:
if (FromType->isRealFloatingType())
goto FloatingIntegralConversion;
if (FromType->isIntegralOrUnscopedEnumerationType())
goto IntegralConversion;
// -- from a pointer type or pointer-to-member type to bool, or
return NK_Type_Narrowing;
// -- from a floating-point type to an integer type, or
//
// -- from an integer type or unscoped enumeration type to a floating-point
// type, except where the source is a constant expression and the actual
// value after conversion will fit into the target type and will produce
// the original value when converted back to the original type, or
case ICK_Floating_Integral:
FloatingIntegralConversion:
if (FromType->isRealFloatingType() && ToType->isIntegralType(Ctx)) {
return NK_Type_Narrowing;
} else if (FromType->isIntegralOrUnscopedEnumerationType() &&
ToType->isRealFloatingType()) {
if (IgnoreFloatToIntegralConversion)
return NK_Not_Narrowing;
const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);
assert(Initializer && "Unknown conversion expression");
// If it's value-dependent, we can't tell whether it's narrowing.
if (Initializer->isValueDependent())
return NK_Dependent_Narrowing;
if (Optional<llvm::APSInt> IntConstantValue =
Initializer->getIntegerConstantExpr(Ctx)) {
// Convert the integer to the floating type.
llvm::APFloat Result(Ctx.getFloatTypeSemantics(ToType));
Result.convertFromAPInt(*IntConstantValue, IntConstantValue->isSigned(),
llvm::APFloat::rmNearestTiesToEven);
// And back.
llvm::APSInt ConvertedValue = *IntConstantValue;
bool ignored;
Result.convertToInteger(ConvertedValue,
llvm::APFloat::rmTowardZero, &ignored);
// If the resulting value is different, this was a narrowing conversion.
if (*IntConstantValue != ConvertedValue) {
ConstantValue = APValue(*IntConstantValue);
ConstantType = Initializer->getType();
return NK_Constant_Narrowing;
}
} else {
// Variables are always narrowings.
return NK_Variable_Narrowing;
}
}
return NK_Not_Narrowing;
// -- from long double to double or float, or from double to float, except
// where the source is a constant expression and the actual value after
// conversion is within the range of values that can be represented (even
// if it cannot be represented exactly), or
case ICK_Floating_Conversion:
if (FromType->isRealFloatingType() && ToType->isRealFloatingType() &&
Ctx.getFloatingTypeOrder(FromType, ToType) == 1) {
// FromType is larger than ToType.
const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);
// If it's value-dependent, we can't tell whether it's narrowing.
if (Initializer->isValueDependent())
return NK_Dependent_Narrowing;
if (Initializer->isCXX11ConstantExpr(Ctx, &ConstantValue)) {
// Constant!
assert(ConstantValue.isFloat());
llvm::APFloat FloatVal = ConstantValue.getFloat();
// Convert the source value into the target type.
bool ignored;
llvm::APFloat::opStatus ConvertStatus = FloatVal.convert(
Ctx.getFloatTypeSemantics(ToType),
llvm::APFloat::rmNearestTiesToEven, &ignored);
// If there was no overflow, the source value is within the range of
// values that can be represented.
if (ConvertStatus & llvm::APFloat::opOverflow) {
ConstantType = Initializer->getType();
return NK_Constant_Narrowing;
}
} else {
return NK_Variable_Narrowing;
}
}
return NK_Not_Narrowing;
// -- from an integer type or unscoped enumeration type to an integer type
// that cannot represent all the values of the original type, except where
// the source is a constant expression and the actual value after
// conversion will fit into the target type and will produce the original
// value when converted back to the original type.
case ICK_Integral_Conversion:
IntegralConversion: {
assert(FromType->isIntegralOrUnscopedEnumerationType());
assert(ToType->isIntegralOrUnscopedEnumerationType());
const bool FromSigned = FromType->isSignedIntegerOrEnumerationType();
const unsigned FromWidth = Ctx.getIntWidth(FromType);
const bool ToSigned = ToType->isSignedIntegerOrEnumerationType();
const unsigned ToWidth = Ctx.getIntWidth(ToType);
if (FromWidth > ToWidth ||
(FromWidth == ToWidth && FromSigned != ToSigned) ||
(FromSigned && !ToSigned)) {
// Not all values of FromType can be represented in ToType.
const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);
// If it's value-dependent, we can't tell whether it's narrowing.
if (Initializer->isValueDependent())
return NK_Dependent_Narrowing;
Optional<llvm::APSInt> OptInitializerValue;
if (!(OptInitializerValue = Initializer->getIntegerConstantExpr(Ctx))) {
// Such conversions on variables are always narrowing.
return NK_Variable_Narrowing;
}
llvm::APSInt &InitializerValue = *OptInitializerValue;
bool Narrowing = false;
if (FromWidth < ToWidth) {
// Negative -> unsigned is narrowing. Otherwise, more bits is never
// narrowing.
if (InitializerValue.isSigned() && InitializerValue.isNegative())
Narrowing = true;
} else {
// Add a bit to the InitializerValue so we don't have to worry about
// signed vs. unsigned comparisons.
InitializerValue = InitializerValue.extend(
InitializerValue.getBitWidth() + 1);
// Convert the initializer to and from the target width and signed-ness.
llvm::APSInt ConvertedValue = InitializerValue;
ConvertedValue = ConvertedValue.trunc(ToWidth);
ConvertedValue.setIsSigned(ToSigned);
ConvertedValue = ConvertedValue.extend(InitializerValue.getBitWidth());
ConvertedValue.setIsSigned(InitializerValue.isSigned());
// If the result is different, this was a narrowing conversion.
if (ConvertedValue != InitializerValue)
Narrowing = true;
}
if (Narrowing) {
ConstantType = Initializer->getType();
ConstantValue = APValue(InitializerValue);
return NK_Constant_Narrowing;
}
}
return NK_Not_Narrowing;
}
default:
// Other kinds of conversions are not narrowings.
return NK_Not_Narrowing;
}
}
/// dump - Print this standard conversion sequence to standard
/// error. Useful for debugging overloading issues.
LLVM_DUMP_METHOD void StandardConversionSequence::dump() const {
raw_ostream &OS = llvm::errs();
bool PrintedSomething = false;
if (First != ICK_Identity) {
OS << GetImplicitConversionName(First);
PrintedSomething = true;
}
if (Second != ICK_Identity) {
if (PrintedSomething) {
OS << " -> ";
}
OS << GetImplicitConversionName(Second);
if (CopyConstructor) {
OS << " (by copy constructor)";
} else if (DirectBinding) {
OS << " (direct reference binding)";
} else if (ReferenceBinding) {
OS << " (reference binding)";
}
PrintedSomething = true;
}
if (Third != ICK_Identity) {
if (PrintedSomething) {
OS << " -> ";
}
OS << GetImplicitConversionName(Third);
PrintedSomething = true;
}
if (!PrintedSomething) {
OS << "No conversions required";
}
}
/// dump - Print this user-defined conversion sequence to standard
/// error. Useful for debugging overloading issues.
void UserDefinedConversionSequence::dump() const {
raw_ostream &OS = llvm::errs();
if (Before.First || Before.Second || Before.Third) {
Before.dump();
OS << " -> ";
}
if (ConversionFunction)
OS << '\'' << *ConversionFunction << '\'';
else
OS << "aggregate initialization";
if (After.First || After.Second || After.Third) {
OS << " -> ";
After.dump();
}
}
/// dump - Print this implicit conversion sequence to standard
/// error. Useful for debugging overloading issues.
void ImplicitConversionSequence::dump() const {
raw_ostream &OS = llvm::errs();
if (hasInitializerListContainerType())
OS << "Worst list element conversion: ";
switch (ConversionKind) {
case StandardConversion:
OS << "Standard conversion: ";
Standard.dump();
break;
case UserDefinedConversion:
OS << "User-defined conversion: ";
UserDefined.dump();
break;
case EllipsisConversion:
OS << "Ellipsis conversion";
break;
case AmbiguousConversion:
OS << "Ambiguous conversion";
break;
case BadConversion:
OS << "Bad conversion";
break;
}
OS << "\n";
}
void AmbiguousConversionSequence::construct() {
new (&conversions()) ConversionSet();
}
void AmbiguousConversionSequence::destruct() {
conversions().~ConversionSet();
}
void
AmbiguousConversionSequence::copyFrom(const AmbiguousConversionSequence &O) {
FromTypePtr = O.FromTypePtr;
ToTypePtr = O.ToTypePtr;
new (&conversions()) ConversionSet(O.conversions());
}
namespace {
// Structure used by DeductionFailureInfo to store
// template argument information.
struct DFIArguments {
TemplateArgument FirstArg;
TemplateArgument SecondArg;
};
// Structure used by DeductionFailureInfo to store
// template parameter and template argument information.
struct DFIParamWithArguments : DFIArguments {
TemplateParameter Param;
};
// Structure used by DeductionFailureInfo to store template argument
// information and the index of the problematic call argument.
struct DFIDeducedMismatchArgs : DFIArguments {
TemplateArgumentList *TemplateArgs;
unsigned CallArgIndex;
};
// Structure used by DeductionFailureInfo to store information about
// unsatisfied constraints.
struct CNSInfo {
TemplateArgumentList *TemplateArgs;
ConstraintSatisfaction Satisfaction;
};
}
/// Convert from Sema's representation of template deduction information
/// to the form used in overload-candidate information.
DeductionFailureInfo
clang::MakeDeductionFailureInfo(ASTContext &Context,
Sema::TemplateDeductionResult TDK,
TemplateDeductionInfo &Info) {
DeductionFailureInfo Result;
Result.Result = static_cast<unsigned>(TDK);
Result.HasDiagnostic = false;
switch (TDK) {
case Sema::TDK_Invalid:
case Sema::TDK_InstantiationDepth:
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_MiscellaneousDeductionFailure:
case Sema::TDK_CUDATargetMismatch:
Result.Data = nullptr;
break;
case Sema::TDK_Incomplete:
case Sema::TDK_InvalidExplicitArguments:
Result.Data = Info.Param.getOpaqueValue();
break;
case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested: {
// FIXME: Should allocate from normal heap so that we can free this later.
auto *Saved = new (Context) DFIDeducedMismatchArgs;
Saved->FirstArg = Info.FirstArg;
Saved->SecondArg = Info.SecondArg;
Saved->TemplateArgs = Info.take();
Saved->CallArgIndex = Info.CallArgIndex;
Result.Data = Saved;
break;
}
case Sema::TDK_NonDeducedMismatch: {
// FIXME: Should allocate from normal heap so that we can free this later.
DFIArguments *Saved = new (Context) DFIArguments;
Saved->FirstArg = Info.FirstArg;
Saved->SecondArg = Info.SecondArg;
Result.Data = Saved;
break;
}
case Sema::TDK_IncompletePack:
// FIXME: It's slightly wasteful to allocate two TemplateArguments for this.
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified: {
// FIXME: Should allocate from normal heap so that we can free this later.
DFIParamWithArguments *Saved = new (Context) DFIParamWithArguments;
Saved->Param = Info.Param;
Saved->FirstArg = Info.FirstArg;
Saved->SecondArg = Info.SecondArg;
Result.Data = Saved;
break;
}
case Sema::TDK_SubstitutionFailure:
Result.Data = Info.take();
if (Info.hasSFINAEDiagnostic()) {
PartialDiagnosticAt *Diag = new (Result.Diagnostic) PartialDiagnosticAt(
SourceLocation(), PartialDiagnostic::NullDiagnostic());
Info.takeSFINAEDiagnostic(*Diag);
Result.HasDiagnostic = true;
}
break;
case Sema::TDK_ConstraintsNotSatisfied: {
CNSInfo *Saved = new (Context) CNSInfo;
Saved->TemplateArgs = Info.take();
Saved->Satisfaction = Info.AssociatedConstraintsSatisfaction;
Result.Data = Saved;
break;
}
case Sema::TDK_Success:
case Sema::TDK_NonDependentConversionFailure:
llvm_unreachable("not a deduction failure");
}
return Result;
}
void DeductionFailureInfo::Destroy() {
switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
case Sema::TDK_Success:
case Sema::TDK_Invalid:
case Sema::TDK_InstantiationDepth:
case Sema::TDK_Incomplete:
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_InvalidExplicitArguments:
case Sema::TDK_CUDATargetMismatch:
case Sema::TDK_NonDependentConversionFailure:
break;
case Sema::TDK_IncompletePack:
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified:
case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested:
case Sema::TDK_NonDeducedMismatch:
// FIXME: Destroy the data?
Data = nullptr;
break;
case Sema::TDK_SubstitutionFailure:
// FIXME: Destroy the template argument list?
Data = nullptr;
if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) {
Diag->~PartialDiagnosticAt();
HasDiagnostic = false;
}
break;
case Sema::TDK_ConstraintsNotSatisfied:
// FIXME: Destroy the template argument list?
Data = nullptr;
if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) {
Diag->~PartialDiagnosticAt();
HasDiagnostic = false;
}
break;
// Unhandled
case Sema::TDK_MiscellaneousDeductionFailure:
break;
}
}
PartialDiagnosticAt *DeductionFailureInfo::getSFINAEDiagnostic() {
if (HasDiagnostic)
return static_cast<PartialDiagnosticAt*>(static_cast<void*>(Diagnostic));
return nullptr;
}
TemplateParameter DeductionFailureInfo::getTemplateParameter() {
switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
case Sema::TDK_Success:
case Sema::TDK_Invalid:
case Sema::TDK_InstantiationDepth:
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_SubstitutionFailure:
case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested:
case Sema::TDK_NonDeducedMismatch:
case Sema::TDK_CUDATargetMismatch:
case Sema::TDK_NonDependentConversionFailure:
case Sema::TDK_ConstraintsNotSatisfied:
return TemplateParameter();
case Sema::TDK_Incomplete:
case Sema::TDK_InvalidExplicitArguments:
return TemplateParameter::getFromOpaqueValue(Data);
case Sema::TDK_IncompletePack:
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified:
return static_cast<DFIParamWithArguments*>(Data)->Param;
// Unhandled
case Sema::TDK_MiscellaneousDeductionFailure:
break;
}
return TemplateParameter();
}
TemplateArgumentList *DeductionFailureInfo::getTemplateArgumentList() {
switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
case Sema::TDK_Success:
case Sema::TDK_Invalid:
case Sema::TDK_InstantiationDepth:
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_Incomplete:
case Sema::TDK_IncompletePack:
case Sema::TDK_InvalidExplicitArguments:
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified:
case Sema::TDK_NonDeducedMismatch:
case Sema::TDK_CUDATargetMismatch:
case Sema::TDK_NonDependentConversionFailure:
return nullptr;
case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested:
return static_cast<DFIDeducedMismatchArgs*>(Data)->TemplateArgs;
case Sema::TDK_SubstitutionFailure:
return static_cast<TemplateArgumentList*>(Data);
case Sema::TDK_ConstraintsNotSatisfied:
return static_cast<CNSInfo*>(Data)->TemplateArgs;
// Unhandled
case Sema::TDK_MiscellaneousDeductionFailure:
break;
}
return nullptr;
}
const TemplateArgument *DeductionFailureInfo::getFirstArg() {
switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
case Sema::TDK_Success:
case Sema::TDK_Invalid:
case Sema::TDK_InstantiationDepth:
case Sema::TDK_Incomplete:
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_InvalidExplicitArguments:
case Sema::TDK_SubstitutionFailure:
case Sema::TDK_CUDATargetMismatch:
case Sema::TDK_NonDependentConversionFailure:
case Sema::TDK_ConstraintsNotSatisfied:
return nullptr;
case Sema::TDK_IncompletePack:
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified:
case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested:
case Sema::TDK_NonDeducedMismatch:
return &static_cast<DFIArguments*>(Data)->FirstArg;
// Unhandled
case Sema::TDK_MiscellaneousDeductionFailure:
break;
}
return nullptr;
}
const TemplateArgument *DeductionFailureInfo::getSecondArg() {
switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
case Sema::TDK_Success:
case Sema::TDK_Invalid:
case Sema::TDK_InstantiationDepth:
case Sema::TDK_Incomplete:
case Sema::TDK_IncompletePack:
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_InvalidExplicitArguments:
case Sema::TDK_SubstitutionFailure:
case Sema::TDK_CUDATargetMismatch:
case Sema::TDK_NonDependentConversionFailure:
case Sema::TDK_ConstraintsNotSatisfied:
return nullptr;
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified:
case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested:
case Sema::TDK_NonDeducedMismatch:
return &static_cast<DFIArguments*>(Data)->SecondArg;
// Unhandled
case Sema::TDK_MiscellaneousDeductionFailure:
break;
}
return nullptr;
}
llvm::Optional<unsigned> DeductionFailureInfo::getCallArgIndex() {
switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested:
return static_cast<DFIDeducedMismatchArgs*>(Data)->CallArgIndex;
default:
return llvm::None;
}
}
bool OverloadCandidateSet::OperatorRewriteInfo::shouldAddReversed(
OverloadedOperatorKind Op) {
if (!AllowRewrittenCandidates)
return false;
return Op == OO_EqualEqual || Op == OO_Spaceship;
}
bool OverloadCandidateSet::OperatorRewriteInfo::shouldAddReversed(
ASTContext &Ctx, const FunctionDecl *FD) {
if (!shouldAddReversed(FD->getDeclName().getCXXOverloadedOperator()))
return false;
// Don't bother adding a reversed candidate that can never be a better
// match than the non-reversed version.
return FD->getNumParams() != 2 ||
!Ctx.hasSameUnqualifiedType(FD->getParamDecl(0)->getType(),
FD->getParamDecl(1)->getType()) ||
FD->hasAttr<EnableIfAttr>();
}
void OverloadCandidateSet::destroyCandidates() {
for (iterator i = begin(), e = end(); i != e; ++i) {
for (auto &C : i->Conversions)
C.~ImplicitConversionSequence();
if (!i->Viable && i->FailureKind == ovl_fail_bad_deduction)
i->DeductionFailure.Destroy();
}
}
void OverloadCandidateSet::clear(CandidateSetKind CSK) {
destroyCandidates();
SlabAllocator.Reset();
NumInlineBytesUsed = 0;
Candidates.clear();
Functions.clear();
Kind = CSK;
}
namespace {
class UnbridgedCastsSet {
struct Entry {
Expr **Addr;
Expr *Saved;
};
SmallVector<Entry, 2> Entries;
public:
void save(Sema &S, Expr *&E) {
assert(E->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
Entry entry = { &E, E };
Entries.push_back(entry);
E = S.stripARCUnbridgedCast(E);
}
void restore() {
for (SmallVectorImpl<Entry>::iterator
i = Entries.begin(), e = Entries.end(); i != e; ++i)
*i->Addr = i->Saved;
}
};
}
/// checkPlaceholderForOverload - Do any interesting placeholder-like
/// preprocessing on the given expression.
///
/// \param unbridgedCasts a collection to which to add unbridged casts;
/// without this, they will be immediately diagnosed as errors
///
/// Return true on unrecoverable error.
static bool
checkPlaceholderForOverload(Sema &S, Expr *&E,
UnbridgedCastsSet *unbridgedCasts = nullptr) {
if (const BuiltinType *placeholder = E->getType()->getAsPlaceholderType()) {
// We can't handle overloaded expressions here because overload
// resolution might reasonably tweak them.
if (placeholder->getKind() == BuiltinType::Overload) return false;
// If the context potentially accepts unbridged ARC casts, strip
// the unbridged cast and add it to the collection for later restoration.
if (placeholder->getKind() == BuiltinType::ARCUnbridgedCast &&
unbridgedCasts) {
unbridgedCasts->save(S, E);
return false;
}
// Go ahead and check everything else.
ExprResult result = S.CheckPlaceholderExpr(E);
if (result.isInvalid())
return true;
E = result.get();
return false;
}
// Nothing to do.
return false;
}
/// checkArgPlaceholdersForOverload - Check a set of call operands for
/// placeholders.
static bool checkArgPlaceholdersForOverload(Sema &S,
MultiExprArg Args,
UnbridgedCastsSet &unbridged) {
for (unsigned i = 0, e = Args.size(); i != e; ++i)
if (checkPlaceholderForOverload(S, Args[i], &unbridged))
return true;
return false;
}
/// Determine whether the given New declaration is an overload of the
/// declarations in Old. This routine returns Ovl_Match or Ovl_NonFunction if
/// New and Old cannot be overloaded, e.g., if New has the same signature as
/// some function in Old (C++ 1.3.10) or if the Old declarations aren't
/// functions (or function templates) at all. When it does return Ovl_Match or
/// Ovl_NonFunction, MatchedDecl will point to the decl that New cannot be
/// overloaded with. This decl may be a UsingShadowDecl on top of the underlying
/// declaration.
///
/// Example: Given the following input:
///
/// void f(int, float); // #1
/// void f(int, int); // #2
/// int f(int, int); // #3
///
/// When we process #1, there is no previous declaration of "f", so IsOverload
/// will not be used.
///
/// When we process #2, Old contains only the FunctionDecl for #1. By comparing
/// the parameter types, we see that #1 and #2 are overloaded (since they have
/// different signatures), so this routine returns Ovl_Overload; MatchedDecl is
/// unchanged.
///
/// When we process #3, Old is an overload set containing #1 and #2. We compare
/// the signatures of #3 to #1 (they're overloaded, so we do nothing) and then
/// #3 to #2. Since the signatures of #3 and #2 are identical (return types of
/// functions are not part of the signature), IsOverload returns Ovl_Match and
/// MatchedDecl will be set to point to the FunctionDecl for #2.
///
/// 'NewIsUsingShadowDecl' indicates that 'New' is being introduced into a class
/// by a using declaration. The rules for whether to hide shadow declarations
/// ignore some properties which otherwise figure into a function template's
/// signature.
Sema::OverloadKind
Sema::CheckOverload(Scope *S, FunctionDecl *New, const LookupResult &Old,
NamedDecl *&Match, bool NewIsUsingDecl) {
for (LookupResult::iterator I = Old.begin(), E = Old.end();
I != E; ++I) {
NamedDecl *OldD = *I;
bool OldIsUsingDecl = false;
if (isa<UsingShadowDecl>(OldD)) {
OldIsUsingDecl = true;
// We can always introduce two using declarations into the same
// context, even if they have identical signatures.
if (NewIsUsingDecl) continue;
OldD = cast<UsingShadowDecl>(OldD)->getTargetDecl();
}
// A using-declaration does not conflict with another declaration
// if one of them is hidden.
if ((OldIsUsingDecl || NewIsUsingDecl) && !isVisible(*I))
continue;
// If either declaration was introduced by a using declaration,
// we'll need to use slightly different rules for matching.
// Essentially, these rules are the normal rules, except that
// function templates hide function templates with different
// return types or template parameter lists.
bool UseMemberUsingDeclRules =
(OldIsUsingDecl || NewIsUsingDecl) && CurContext->isRecord() &&
!New->getFriendObjectKind();
if (FunctionDecl *OldF = OldD->getAsFunction()) {
if (!IsOverload(New, OldF, UseMemberUsingDeclRules)) {
if (UseMemberUsingDeclRules && OldIsUsingDecl) {
HideUsingShadowDecl(S, cast<UsingShadowDecl>(*I));
continue;
}
if (!isa<FunctionTemplateDecl>(OldD) &&
!shouldLinkPossiblyHiddenDecl(*I, New))
continue;
Match = *I;
return Ovl_Match;
}
// Builtins that have custom typechecking or have a reference should
// not be overloadable or redeclarable.
if (!getASTContext().canBuiltinBeRedeclared(OldF)) {
Match = *I;
return Ovl_NonFunction;
}
} else if (isa<UsingDecl>(OldD) || isa<UsingPackDecl>(OldD)) {
// We can overload with these, which can show up when doing
// redeclaration checks for UsingDecls.
assert(Old.getLookupKind() == LookupUsingDeclName);
} else if (isa<TagDecl>(OldD)) {
// We can always overload with tags by hiding them.
} else if (auto *UUD = dyn_cast<UnresolvedUsingValueDecl>(OldD)) {
// Optimistically assume that an unresolved using decl will
// overload; if it doesn't, we'll have to diagnose during
// template instantiation.
//
// Exception: if the scope is dependent and this is not a class
// member, the using declaration can only introduce an enumerator.
if (UUD->getQualifier()->isDependent() && !UUD->isCXXClassMember()) {
Match = *I;
return Ovl_NonFunction;
}
} else {
// (C++ 13p1):
// Only function declarations can be overloaded; object and type
// declarations cannot be overloaded.
Match = *I;
return Ovl_NonFunction;
}
}
// C++ [temp.friend]p1:
// For a friend function declaration that is not a template declaration:
// -- if the name of the friend is a qualified or unqualified template-id,
// [...], otherwise
// -- if the name of the friend is a qualified-id and a matching
// non-template function is found in the specified class or namespace,
// the friend declaration refers to that function, otherwise,
// -- if the name of the friend is a qualified-id and a matching function
// template is found in the specified class or namespace, the friend
// declaration refers to the deduced specialization of that function
// template, otherwise
// -- the name shall be an unqualified-id [...]
// If we get here for a qualified friend declaration, we've just reached the
// third bullet. If the type of the friend is dependent, skip this lookup
// until instantiation.
if (New->getFriendObjectKind() && New->getQualifier() &&
!New->getDescribedFunctionTemplate() &&
!New->getDependentSpecializationInfo() &&
!New->getType()->isDependentType()) {
LookupResult TemplateSpecResult(LookupResult::Temporary, Old);
TemplateSpecResult.addAllDecls(Old);
if (CheckFunctionTemplateSpecialization(New, nullptr, TemplateSpecResult,
/*QualifiedFriend*/true)) {
New->setInvalidDecl();
return Ovl_Overload;
}
Match = TemplateSpecResult.getAsSingle<FunctionDecl>();
return Ovl_Match;
}
return Ovl_Overload;
}
bool Sema::IsOverload(FunctionDecl *New, FunctionDecl *Old,
bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs,
bool ConsiderRequiresClauses) {
// C++ [basic.start.main]p2: This function shall not be overloaded.
if (New->isMain())
return false;
// MSVCRT user defined entry points cannot be overloaded.
if (New->isMSVCRTEntryPoint())
return false;
FunctionTemplateDecl *OldTemplate = Old->getDescribedFunctionTemplate();
FunctionTemplateDecl *NewTemplate = New->getDescribedFunctionTemplate();
// C++ [temp.fct]p2:
// A function template can be overloaded with other function templates
// and with normal (non-template) functions.
if ((OldTemplate == nullptr) != (NewTemplate == nullptr))
return true;
// Is the function New an overload of the function Old?
QualType OldQType = Context.getCanonicalType(Old->getType());
QualType NewQType = Context.getCanonicalType(New->getType());
// Compare the signatures (C++ 1.3.10) of the two functions to
// determine whether they are overloads. If we find any mismatch
// in the signature, they are overloads.
// If either of these functions is a K&R-style function (no
// prototype), then we consider them to have matching signatures.
if (isa<FunctionNoProtoType>(OldQType.getTypePtr()) ||
isa<FunctionNoProtoType>(NewQType.getTypePtr()))
return false;
const FunctionProtoType *OldType = cast<FunctionProtoType>(OldQType);
const FunctionProtoType *NewType = cast<FunctionProtoType>(NewQType);
// The signature of a function includes the types of its
// parameters (C++ 1.3.10), which includes the presence or absence
// of the ellipsis; see C++ DR 357).
if (OldQType != NewQType &&
(OldType->getNumParams() != NewType->getNumParams() ||
OldType->isVariadic() != NewType->isVariadic() ||
!FunctionParamTypesAreEqual(OldType, NewType)))
return true;
// C++ [temp.over.link]p4:
// The signature of a function template consists of its function
// signature, its return type and its template parameter list. The names
// of the template parameters are significant only for establishing the
// relationship between the template parameters and the rest of the
// signature.
//
// We check the return type and template parameter lists for function
// templates first; the remaining checks follow.
//
// However, we don't consider either of these when deciding whether
// a member introduced by a shadow declaration is hidden.
if (!UseMemberUsingDeclRules && NewTemplate &&
(!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(),
OldTemplate->getTemplateParameters(),
false, TPL_TemplateMatch) ||
!Context.hasSameType(Old->getDeclaredReturnType(),
New->getDeclaredReturnType())))
return true;
// If the function is a class member, its signature includes the
// cv-qualifiers (if any) and ref-qualifier (if any) on the function itself.
//
// As part of this, also check whether one of the member functions
// is static, in which case they are not overloads (C++
// 13.1p2). While not part of the definition of the signature,
// this check is important to determine whether these functions
// can be overloaded.
CXXMethodDecl *OldMethod = dyn_cast<CXXMethodDecl>(Old);
CXXMethodDecl *NewMethod = dyn_cast<CXXMethodDecl>(New);
if (OldMethod && NewMethod &&
!OldMethod->isStatic() && !NewMethod->isStatic()) {
if (OldMethod->getRefQualifier() != NewMethod->getRefQualifier()) {
if (!UseMemberUsingDeclRules &&
(OldMethod->getRefQualifier() == RQ_None ||
NewMethod->getRefQualifier() == RQ_None)) {
// C++0x [over.load]p2:
// - Member function declarations with the same name and the same
// parameter-type-list as well as member function template
// declarations with the same name, the same parameter-type-list, and
// the same template parameter lists cannot be overloaded if any of
// them, but not all, have a ref-qualifier (8.3.5).
Diag(NewMethod->getLocation(), diag::err_ref_qualifier_overload)
<< NewMethod->getRefQualifier() << OldMethod->getRefQualifier();
Diag(OldMethod->getLocation(), diag::note_previous_declaration);
}
return true;
}
// We may not have applied the implicit const for a constexpr member
// function yet (because we haven't yet resolved whether this is a static
// or non-static member function). Add it now, on the assumption that this
// is a redeclaration of OldMethod.
auto OldQuals = OldMethod->getMethodQualifiers();
auto NewQuals = NewMethod->getMethodQualifiers();
if (!getLangOpts().CPlusPlus14 && NewMethod->isConstexpr() &&
!isa<CXXConstructorDecl>(NewMethod))
NewQuals.addConst();
// We do not allow overloading based off of '__restrict'.
OldQuals.removeRestrict();
NewQuals.removeRestrict();
if (OldQuals != NewQuals)
return true;
}
// Though pass_object_size is placed on parameters and takes an argument, we
// consider it to be a function-level modifier for the sake of function
// identity. Either the function has one or more parameters with
// pass_object_size or it doesn't.
if (functionHasPassObjectSizeParams(New) !=
functionHasPassObjectSizeParams(Old))
return true;
// enable_if attributes are an order-sensitive part of the signature.
for (specific_attr_iterator<EnableIfAttr>
NewI = New->specific_attr_begin<EnableIfAttr>(),
NewE = New->specific_attr_end<EnableIfAttr>(),
OldI = Old->specific_attr_begin<EnableIfAttr>(),
OldE = Old->specific_attr_end<EnableIfAttr>();
NewI != NewE || OldI != OldE; ++NewI, ++OldI) {
if (NewI == NewE || OldI == OldE)
return true;
llvm::FoldingSetNodeID NewID, OldID;
NewI->getCond()->Profile(NewID, Context, true);
OldI->getCond()->Profile(OldID, Context, true);
if (NewID != OldID)
return true;
}
if (getLangOpts().CUDA && ConsiderCudaAttrs) {
// Don't allow overloading of destructors. (In theory we could, but it
// would be a giant change to clang.)
if (!isa<CXXDestructorDecl>(New)) {
CUDAFunctionTarget NewTarget = IdentifyCUDATarget(New),
OldTarget = IdentifyCUDATarget(Old);
if (NewTarget != CFT_InvalidTarget) {
assert((OldTarget != CFT_InvalidTarget) &&
"Unexpected invalid target.");
// Allow overloading of functions with same signature and different CUDA
// target attributes.
if (NewTarget != OldTarget)
return true;
}
}
}
if (ConsiderRequiresClauses) {
Expr *NewRC = New->getTrailingRequiresClause(),
*OldRC = Old->getTrailingRequiresClause();
if ((NewRC != nullptr) != (OldRC != nullptr))
// RC are most certainly different - these are overloads.
return true;
if (NewRC) {
llvm::FoldingSetNodeID NewID, OldID;
NewRC->Profile(NewID, Context, /*Canonical=*/true);
OldRC->Profile(OldID, Context, /*Canonical=*/true);
if (NewID != OldID)
// RCs are not equivalent - these are overloads.
return true;
}
}
// The signatures match; this is not an overload.
return false;
}
/// Tries a user-defined conversion from From to ToType.
///
/// Produces an implicit conversion sequence for when a standard conversion
/// is not an option. See TryImplicitConversion for more information.
static ImplicitConversionSequence
TryUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
bool SuppressUserConversions,
AllowedExplicit AllowExplicit,
bool InOverloadResolution,
bool CStyle,
bool AllowObjCWritebackConversion,
bool AllowObjCConversionOnExplicit) {
ImplicitConversionSequence ICS;
if (SuppressUserConversions) {
// We're not in the case above, so there is no conversion that
// we can perform.
ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
return ICS;
}
// Attempt user-defined conversion.
OverloadCandidateSet Conversions(From->getExprLoc(),
OverloadCandidateSet::CSK_Normal);
switch (IsUserDefinedConversion(S, From, ToType, ICS.UserDefined,
Conversions, AllowExplicit,
AllowObjCConversionOnExplicit)) {
case OR_Success:
case OR_Deleted:
ICS.setUserDefined();
// C++ [over.ics.user]p4:
// A conversion of an expression of class type to the same class
// type is given Exact Match rank, and a conversion of an
// expression of class type to a base class of that type is
// given Conversion rank, in spite of the fact that a copy
// constructor (i.e., a user-defined conversion function) is
// called for those cases.
if (CXXConstructorDecl *Constructor
= dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) {
QualType FromCanon
= S.Context.getCanonicalType(From->getType().getUnqualifiedType());
QualType ToCanon
= S.Context.getCanonicalType(ToType).getUnqualifiedType();
if (Constructor->isCopyConstructor() &&
(FromCanon == ToCanon ||
S.IsDerivedFrom(From->getBeginLoc(), FromCanon, ToCanon))) {
// Turn this into a "standard" conversion sequence, so that it
// gets ranked with standard conversion sequences.
DeclAccessPair Found = ICS.UserDefined.FoundConversionFunction;
ICS.setStandard();
ICS.Standard.setAsIdentityConversion();
ICS.Standard.setFromType(From->getType());
ICS.Standard.setAllToTypes(ToType);
ICS.Standard.CopyConstructor = Constructor;
ICS.Standard.FoundCopyConstructor = Found;
if (ToCanon != FromCanon)
ICS.Standard.Second = ICK_Derived_To_Base;
}
}
break;
case OR_Ambiguous:
ICS.setAmbiguous();
ICS.Ambiguous.setFromType(From->getType());
ICS.Ambiguous.setToType(ToType);
for (OverloadCandidateSet::iterator Cand = Conversions.begin();
Cand != Conversions.end(); ++Cand)
if (Cand->Best)
ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function);
break;
// Fall through.
case OR_No_Viable_Function:
ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
break;
}
return ICS;
}
/// TryImplicitConversion - Attempt to perform an implicit conversion
/// from the given expression (Expr) to the given type (ToType). This
/// function returns an implicit conversion sequence that can be used
/// to perform the initialization. Given
///
/// void f(float f);
/// void g(int i) { f(i); }
///
/// this routine would produce an implicit conversion sequence to
/// describe the initialization of f from i, which will be a standard
/// conversion sequence containing an lvalue-to-rvalue conversion (C++
/// 4.1) followed by a floating-integral conversion (C++ 4.9).
//
/// Note that this routine only determines how the conversion can be
/// performed; it does not actually perform the conversion. As such,
/// it will not produce any diagnostics if no conversion is available,
/// but will instead return an implicit conversion sequence of kind
/// "BadConversion".
///
/// If @p SuppressUserConversions, then user-defined conversions are
/// not permitted.
/// If @p AllowExplicit, then explicit user-defined conversions are
/// permitted.
///
/// \param AllowObjCWritebackConversion Whether we allow the Objective-C
/// writeback conversion, which allows __autoreleasing id* parameters to
/// be initialized with __strong id* or __weak id* arguments.
static ImplicitConversionSequence
TryImplicitConversion(Sema &S, Expr *From, QualType ToType,
bool SuppressUserConversions,
AllowedExplicit AllowExplicit,
bool InOverloadResolution,
bool CStyle,
bool AllowObjCWritebackConversion,
bool AllowObjCConversionOnExplicit) {
ImplicitConversionSequence ICS;
if (IsStandardConversion(S, From, ToType, InOverloadResolution,
ICS.Standard, CStyle, AllowObjCWritebackConversion)){
ICS.setStandard();
return ICS;
}
if (!S.getLangOpts().CPlusPlus) {
ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
return ICS;
}
// C++ [over.ics.user]p4:
// A conversion of an expression of class type to the same class
// type is given Exact Match rank, and a conversion of an
// expression of class type to a base class of that type is
// given Conversion rank, in spite of the fact that a copy/move
// constructor (i.e., a user-defined conversion function) is
// called for those cases.
QualType FromType = From->getType();
if (ToType->getAs<RecordType>() && FromType->getAs<RecordType>() &&
(S.Context.hasSameUnqualifiedType(FromType, ToType) ||
S.IsDerivedFrom(From->getBeginLoc(), FromType, ToType))) {
ICS.setStandard();
ICS.Standard.setAsIdentityConversion();
ICS.Standard.setFromType(FromType);
ICS.Standard.setAllToTypes(ToType);
// We don't actually check at this point whether there is a valid
// copy/move constructor, since overloading just assumes that it
// exists. When we actually perform initialization, we'll find the
// appropriate constructor to copy the returned object, if needed.
ICS.Standard.CopyConstructor = nullptr;
// Determine whether this is considered a derived-to-base conversion.
if (!S.Context.hasSameUnqualifiedType(FromType, ToType))
ICS.Standard.Second = ICK_Derived_To_Base;
return ICS;
}
return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions,
AllowExplicit, InOverloadResolution, CStyle,
AllowObjCWritebackConversion,
AllowObjCConversionOnExplicit);
}
ImplicitConversionSequence
Sema::TryImplicitConversion(Expr *From, QualType ToType,
bool SuppressUserConversions,
AllowedExplicit AllowExplicit,
bool InOverloadResolution,
bool CStyle,
bool AllowObjCWritebackConversion) {
return ::TryImplicitConversion(*this, From, ToType, SuppressUserConversions,
AllowExplicit, InOverloadResolution, CStyle,
AllowObjCWritebackConversion,
/*AllowObjCConversionOnExplicit=*/false);
}
/// PerformImplicitConversion - Perform an implicit conversion of the
/// expression From to the type ToType. Returns the
/// converted expression. Flavor is the kind of conversion we're
/// performing, used in the error message. If @p AllowExplicit,
/// explicit user-defined conversions are permitted.
ExprResult Sema::PerformImplicitConversion(Expr *From, QualType ToType,
AssignmentAction Action,
bool AllowExplicit) {
if (checkPlaceholderForOverload(*this, From))
return ExprError();
// Objective-C ARC: Determine whether we will allow the writeback conversion.
bool AllowObjCWritebackConversion
= getLangOpts().ObjCAutoRefCount &&
(Action == AA_Passing || Action == AA_Sending);
if (getLangOpts().ObjC)
CheckObjCBridgeRelatedConversions(From->getBeginLoc(), ToType,
From->getType(), From);
ImplicitConversionSequence ICS = ::TryImplicitConversion(
*this, From, ToType,
/*SuppressUserConversions=*/false,
AllowExplicit ? AllowedExplicit::All : AllowedExplicit::None,
/*InOverloadResolution=*/false,
/*CStyle=*/false, AllowObjCWritebackConversion,
/*AllowObjCConversionOnExplicit=*/false);
return PerformImplicitConversion(From, ToType, ICS, Action);
}
/// Determine whether the conversion from FromType to ToType is a valid
/// conversion that strips "noexcept" or "noreturn" off the nested function
/// type.
bool Sema::IsFunctionConversion(QualType FromType, QualType ToType,
QualType &ResultTy) {
if (Context.hasSameUnqualifiedType(FromType, ToType))
return false;
// Permit the conversion F(t __attribute__((noreturn))) -> F(t)
// or F(t noexcept) -> F(t)
// where F adds one of the following at most once:
// - a pointer
// - a member pointer
// - a block pointer
// Changes here need matching changes in FindCompositePointerType.
CanQualType CanTo = Context.getCanonicalType(ToType);
CanQualType CanFrom = Context.getCanonicalType(FromType);
Type::TypeClass TyClass = CanTo->getTypeClass();
if (TyClass != CanFrom->getTypeClass()) return false;
if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto) {
if (TyClass == Type::Pointer) {
CanTo = CanTo.castAs<PointerType>()->getPointeeType();
CanFrom = CanFrom.castAs<PointerType>()->getPointeeType();
} else if (TyClass == Type::BlockPointer) {
CanTo = CanTo.castAs<BlockPointerType>()->getPointeeType();
CanFrom = CanFrom.castAs<BlockPointerType>()->getPointeeType();
} else if (TyClass == Type::MemberPointer) {
auto ToMPT = CanTo.castAs<MemberPointerType>();
auto FromMPT = CanFrom.castAs<MemberPointerType>();
// A function pointer conversion cannot change the class of the function.
if (ToMPT->getClass() != FromMPT->getClass())
return false;
CanTo = ToMPT->getPointeeType();
CanFrom = FromMPT->getPointeeType();
} else {
return false;
}
TyClass = CanTo->getTypeClass();
if (TyClass != CanFrom->getTypeClass()) return false;
if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto)
return false;
}
const auto *FromFn = cast<FunctionType>(CanFrom);
FunctionType::ExtInfo FromEInfo = FromFn->getExtInfo();
const auto *ToFn = cast<FunctionType>(CanTo);
FunctionType::ExtInfo ToEInfo = ToFn->getExtInfo();
bool Changed = false;
// Drop 'noreturn' if not present in target type.
if (FromEInfo.getNoReturn() && !ToEInfo.getNoReturn()) {
FromFn = Context.adjustFunctionType(FromFn, FromEInfo.withNoReturn(false));
Changed = true;
}
// Drop 'noexcept' if not present in target type.
if (const auto *FromFPT = dyn_cast<FunctionProtoType>(FromFn)) {
const auto *ToFPT = cast<FunctionProtoType>(ToFn);
if (FromFPT->isNothrow() && !ToFPT->isNothrow()) {
FromFn = cast<FunctionType>(
Context.getFunctionTypeWithExceptionSpec(QualType(FromFPT, 0),
EST_None)
.getTypePtr());
Changed = true;
}
// Convert FromFPT's ExtParameterInfo if necessary. The conversion is valid
// only if the ExtParameterInfo lists of the two function prototypes can be
// merged and the merged list is identical to ToFPT's ExtParameterInfo list.
SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos;
bool CanUseToFPT, CanUseFromFPT;
if (Context.mergeExtParameterInfo(ToFPT, FromFPT, CanUseToFPT,
CanUseFromFPT, NewParamInfos) &&
CanUseToFPT && !CanUseFromFPT) {
FunctionProtoType::ExtProtoInfo ExtInfo = FromFPT->getExtProtoInfo();
ExtInfo.ExtParameterInfos =
NewParamInfos.empty() ? nullptr : NewParamInfos.data();
QualType QT = Context.getFunctionType(FromFPT->getReturnType(),
FromFPT->getParamTypes(), ExtInfo);
FromFn = QT->getAs<FunctionType>();
Changed = true;
}
}
if (!Changed)
return false;
assert(QualType(FromFn, 0).isCanonical());
if (QualType(FromFn, 0) != CanTo) return false;
ResultTy = ToType;
return true;
}
/// Determine whether the conversion from FromType to ToType is a valid
/// vector conversion.
///
/// \param ICK Will be set to the vector conversion kind, if this is a vector
/// conversion.
static bool IsVectorConversion(Sema &S, QualType FromType,
QualType ToType, ImplicitConversionKind &ICK) {
// We need at least one of these types to be a vector type to have a vector
// conversion.
if (!ToType->isVectorType() && !FromType->isVectorType())
return false;
// Identical types require no conversions.
if (S.Context.hasSameUnqualifiedType(FromType, ToType))
return false;
// There are no conversions between extended vector types, only identity.
if (ToType->isExtVectorType()) {
// There are no conversions between extended vector types other than the
// identity conversion.
if (FromType->isExtVectorType())
return false;
// Vector splat from any arithmetic type to a vector.
if (FromType->isArithmeticType()) {
ICK = ICK_Vector_Splat;
return true;
}
}
if (ToType->isSizelessBuiltinType() || FromType->isSizelessBuiltinType())
if (S.Context.areCompatibleSveTypes(FromType, ToType) ||
S.Context.areLaxCompatibleSveTypes(FromType, ToType)) {
ICK = ICK_SVE_Vector_Conversion;
return true;
}
// We can perform the conversion between vector types in the following cases:
// 1)vector types are equivalent AltiVec and GCC vector types
// 2)lax vector conversions are permitted and the vector types are of the
// same size
// 3)the destination type does not have the ARM MVE strict-polymorphism
// attribute, which inhibits lax vector conversion for overload resolution
// only
if (ToType->isVectorType() && FromType->isVectorType()) {
if (S.Context.areCompatibleVectorTypes(FromType, ToType) ||
(S.isLaxVectorConversion(FromType, ToType) &&
!ToType->hasAttr(attr::ArmMveStrictPolymorphism))) {
ICK = ICK_Vector_Conversion;
return true;
}
}
return false;
}
static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
bool InOverloadResolution,
StandardConversionSequence &SCS,
bool CStyle);
/// IsStandardConversion - Determines whether there is a standard
/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the
/// expression From to the type ToType. Standard conversion sequences
/// only consider non-class types; for conversions that involve class
/// types, use TryImplicitConversion. If a conversion exists, SCS will
/// contain the standard conversion sequence required to perform this
/// conversion and this routine will return true. Otherwise, this
/// routine will return false and the value of SCS is unspecified.
static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
bool InOverloadResolution,
StandardConversionSequence &SCS,
bool CStyle,
bool AllowObjCWritebackConversion) {
QualType FromType = From->getType();
// Standard conversions (C++ [conv])
SCS.setAsIdentityConversion();
SCS.IncompatibleObjC = false;
SCS.setFromType(FromType);
SCS.CopyConstructor = nullptr;
// There are no standard conversions for class types in C++, so
// abort early. When overloading in C, however, we do permit them.
if (S.getLangOpts().CPlusPlus &&
(FromType->isRecordType() || ToType->isRecordType()))
return false;
// The first conversion can be an lvalue-to-rvalue conversion,
// array-to-pointer conversion, or function-to-pointer conversion
// (C++ 4p1).
if (FromType == S.Context.OverloadTy) {
DeclAccessPair AccessPair;
if (FunctionDecl *Fn
= S.ResolveAddressOfOverloadedFunction(From, ToType, false,
AccessPair)) {
// We were able to resolve the address of the overloaded function,
// so we can convert to the type of that function.
FromType = Fn->getType();
SCS.setFromType(FromType);
// we can sometimes resolve &foo<int> regardless of ToType, so check
// if the type matches (identity) or we are converting to bool
if (!S.Context.hasSameUnqualifiedType(
S.ExtractUnqualifiedFunctionType(ToType), FromType)) {
QualType resultTy;
// if the function type matches except for [[noreturn]], it's ok
if (!S.IsFunctionConversion(FromType,
S.ExtractUnqualifiedFunctionType(ToType), resultTy))
// otherwise, only a boolean conversion is standard
if (!ToType->isBooleanType())
return false;
}
// Check if the "from" expression is taking the address of an overloaded
// function and recompute the FromType accordingly. Take advantage of the
// fact that non-static member functions *must* have such an address-of
// expression.
CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn);
if (Method && !Method->isStatic()) {
assert(isa<UnaryOperator>(From->IgnoreParens()) &&
"Non-unary operator on non-static member address");
assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode()
== UO_AddrOf &&
"Non-address-of operator on non-static member address");
const Type *ClassType
= S.Context.getTypeDeclType(Method->getParent()).getTypePtr();
FromType = S.Context.getMemberPointerType(FromType, ClassType);
} else if (isa<UnaryOperator>(From->IgnoreParens())) {
assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode() ==
UO_AddrOf &&
"Non-address-of operator for overloaded function expression");
FromType = S.Context.getPointerType(FromType);
}
// Check that we've computed the proper type after overload resolution.
// FIXME: FixOverloadedFunctionReference has side-effects; we shouldn't
// be calling it from within an NDEBUG block.
assert(S.Context.hasSameType(
FromType,
S.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType()));
} else {
return false;
}
}
// Lvalue-to-rvalue conversion (C++11 4.1):
// A glvalue (3.10) of a non-function, non-array type T can
// be converted to a prvalue.
bool argIsLValue = From->isGLValue();
if (argIsLValue &&
!FromType->isFunctionType() && !FromType->isArrayType() &&
S.Context.getCanonicalType(FromType) != S.Context.OverloadTy) {
SCS.First = ICK_Lvalue_To_Rvalue;
// C11 6.3.2.1p2:
// ... if the lvalue has atomic type, the value has the non-atomic version
// of the type of the lvalue ...
if (const AtomicType *Atomic = FromType->getAs<AtomicType>())
FromType = Atomic->getValueType();
// If T is a non-class type, the type of the rvalue is the
// cv-unqualified version of T. Otherwise, the type of the rvalue
// is T (C++ 4.1p1). C++ can't get here with class types; in C, we
// just strip the qualifiers because they don't matter.
FromType = FromType.getUnqualifiedType();
} else if (FromType->isArrayType()) {
// Array-to-pointer conversion (C++ 4.2)
SCS.First = ICK_Array_To_Pointer;
// An lvalue or rvalue of type "array of N T" or "array of unknown
// bound of T" can be converted to an rvalue of type "pointer to
// T" (C++ 4.2p1).
FromType = S.Context.getArrayDecayedType(FromType);
if (S.IsStringLiteralToNonConstPointerConversion(From, ToType)) {
// This conversion is deprecated in C++03 (D.4)
SCS.DeprecatedStringLiteralToCharPtr = true;
// For the purpose of ranking in overload resolution
// (13.3.3.1.1), this conversion is considered an
// array-to-pointer conversion followed by a qualification
// conversion (4.4). (C++ 4.2p2)
SCS.Second = ICK_Identity;
SCS.Third = ICK_Qualification;
SCS.QualificationIncludesObjCLifetime = false;
SCS.setAllToTypes(FromType);
return true;
}
} else if (FromType->isFunctionType() && argIsLValue) {
// Function-to-pointer conversion (C++ 4.3).
SCS.First = ICK_Function_To_Pointer;
if (auto *DRE = dyn_cast<DeclRefExpr>(From->IgnoreParenCasts()))
if (auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl()))
if (!S.checkAddressOfFunctionIsAvailable(FD))
return false;
// An lvalue of function type T can be converted to an rvalue of
// type "pointer to T." The result is a pointer to the
// function. (C++ 4.3p1).
FromType = S.Context.getPointerType(FromType);
} else {
// We don't require any conversions for the first step.
SCS.First = ICK_Identity;
}
SCS.setToType(0, FromType);
// The second conversion can be an integral promotion, floating
// point promotion, integral conversion, floating point conversion,
// floating-integral conversion, pointer conversion,
// pointer-to-member conversion, or boolean conversion (C++ 4p1).
// For overloading in C, this can also be a "compatible-type"
// conversion.
bool IncompatibleObjC = false;
ImplicitConversionKind SecondICK = ICK_Identity;
if (S.Context.hasSameUnqualifiedType(FromType, ToType)) {
// The unqualified versions of the types are the same: there's no
// conversion to do.
SCS.Second = ICK_Identity;
} else if (S.IsIntegralPromotion(From, FromType, ToType)) {
// Integral promotion (C++ 4.5).
SCS.Second = ICK_Integral_Promotion;
FromType = ToType.getUnqualifiedType();
} else if (S.IsFloatingPointPromotion(FromType, ToType)) {
// Floating point promotion (C++ 4.6).
SCS.Second = ICK_Floating_Promotion;
FromType = ToType.getUnqualifiedType();
} else if (S.IsComplexPromotion(FromType, ToType)) {
// Complex promotion (Clang extension)
SCS.Second = ICK_Complex_Promotion;
FromType = ToType.getUnqualifiedType();
} else if (ToType->isBooleanType() &&
(FromType->isArithmeticType() ||
FromType->isAnyPointerType() ||
FromType->isBlockPointerType() ||
FromType->isMemberPointerType())) {
// Boolean conversions (C++ 4.12).
SCS.Second = ICK_Boolean_Conversion;
FromType = S.Context.BoolTy;
} else if (FromType->isIntegralOrUnscopedEnumerationType() &&
ToType->isIntegralType(S.Context)) {
// Integral conversions (C++ 4.7).
SCS.Second = ICK_Integral_Conversion;
FromType = ToType.getUnqualifiedType();
} else if (FromType->isAnyComplexType() && ToType->isAnyComplexType()) {
// Complex conversions (C99 6.3.1.6)
SCS.Second = ICK_Complex_Conversion;
FromType = ToType.getUnqualifiedType();
} else if ((FromType->isAnyComplexType() && ToType->isArithmeticType()) ||
(ToType->isAnyComplexType() && FromType->isArithmeticType())) {
// Complex-real conversions (C99 6.3.1.7)
SCS.Second = ICK_Complex_Real;
FromType = ToType.getUnqualifiedType();
} else if (FromType->isRealFloatingType() && ToType->isRealFloatingType()) {
// FIXME: disable conversions between long double, __ibm128 and __float128
// if their representation is different until there is back end support
// We of course allow this conversion if long double is really double.
// Conversions between bfloat and other floats are not permitted.
if (FromType == S.Context.BFloat16Ty || ToType == S.Context.BFloat16Ty)
return false;
// Conversions between IEEE-quad and IBM-extended semantics are not
// permitted.
const llvm::fltSemantics &FromSem =
S.Context.getFloatTypeSemantics(FromType);
const llvm::fltSemantics &ToSem = S.Context.getFloatTypeSemantics(ToType);
if ((&FromSem == &llvm::APFloat::PPCDoubleDouble() &&
&ToSem == &llvm::APFloat::IEEEquad()) ||
(&FromSem == &llvm::APFloat::IEEEquad() &&
&ToSem == &llvm::APFloat::PPCDoubleDouble()))
return false;
// Floating point conversions (C++ 4.8).
SCS.Second = ICK_Floating_Conversion;
FromType = ToType.getUnqualifiedType();
} else if ((FromType->isRealFloatingType() &&
ToType->isIntegralType(S.Context)) ||
(FromType->isIntegralOrUnscopedEnumerationType() &&
ToType->isRealFloatingType())) {
// Conversions between bfloat and int are not permitted.
if (FromType->isBFloat16Type() || ToType->isBFloat16Type())
return false;
// Floating-integral conversions (C++ 4.9).
SCS.Second = ICK_Floating_Integral;
FromType = ToType.getUnqualifiedType();
} else if (S.IsBlockPointerConversion(FromType, ToType, FromType)) {
SCS.Second = ICK_Block_Pointer_Conversion;
} else if (AllowObjCWritebackConversion &&
S.isObjCWritebackConversion(FromType, ToType, FromType)) {
SCS.Second = ICK_Writeback_Conversion;
} else if (S.IsPointerConversion(From, FromType, ToType, InOverloadResolution,
FromType, IncompatibleObjC)) {
// Pointer conversions (C++ 4.10).
SCS.Second = ICK_Pointer_Conversion;
SCS.IncompatibleObjC = IncompatibleObjC;
FromType = FromType.getUnqualifiedType();
} else if (S.IsMemberPointerConversion(From, FromType, ToType,
InOverloadResolution, FromType)) {
// Pointer to member conversions (4.11).
SCS.Second = ICK_Pointer_Member;
} else if (IsVectorConversion(S, FromType, ToType, SecondICK)) {
SCS.Second = SecondICK;
FromType = ToType.getUnqualifiedType();
} else if (!S.getLangOpts().CPlusPlus &&
S.Context.typesAreCompatible(ToType, FromType)) {
// Compatible conversions (Clang extension for C function overloading)
SCS.Second = ICK_Compatible_Conversion;
FromType = ToType.getUnqualifiedType();
} else if (IsTransparentUnionStandardConversion(S, From, ToType,
InOverloadResolution,
SCS, CStyle)) {
SCS.Second = ICK_TransparentUnionConversion;
FromType = ToType;
} else if (tryAtomicConversion(S, From, ToType, InOverloadResolution, SCS,
CStyle)) {
// tryAtomicConversion has updated the standard conversion sequence
// appropriately.
return true;
} else if (ToType->isEventT() &&
From->isIntegerConstantExpr(S.getASTContext()) &&
From->EvaluateKnownConstInt(S.getASTContext()) == 0) {
SCS.Second = ICK_Zero_Event_Conversion;
FromType = ToType;
} else if (ToType->isQueueT() &&
From->isIntegerConstantExpr(S.getASTContext()) &&
(From->EvaluateKnownConstInt(S.getASTContext()) == 0)) {
SCS.Second = ICK_Zero_Queue_Conversion;
FromType = ToType;
} else if (ToType->isSamplerT() &&
From->isIntegerConstantExpr(S.getASTContext())) {
SCS.Second = ICK_Compatible_Conversion;
FromType = ToType;
} else {
// No second conversion required.
SCS.Second = ICK_Identity;
}
SCS.setToType(1, FromType);
// The third conversion can be a function pointer conversion or a
// qualification conversion (C++ [conv.fctptr], [conv.qual]).
bool ObjCLifetimeConversion;
if (S.IsFunctionConversion(FromType, ToType, FromType)) {
// Function pointer conversions (removing 'noexcept') including removal of
// 'noreturn' (Clang extension).
SCS.Third = ICK_Function_Conversion;
} else if (S.IsQualificationConversion(FromType, ToType, CStyle,
ObjCLifetimeConversion)) {
SCS.Third = ICK_Qualification;
SCS.QualificationIncludesObjCLifetime = ObjCLifetimeConversion;
FromType = ToType;
} else {
// No conversion required
SCS.Third = ICK_Identity;
}
// C++ [over.best.ics]p6:
// [...] Any difference in top-level cv-qualification is
// subsumed by the initialization itself and does not constitute
// a conversion. [...]
QualType CanonFrom = S.Context.getCanonicalType(FromType);
QualType CanonTo = S.Context.getCanonicalType(ToType);
if (CanonFrom.getLocalUnqualifiedType()
== CanonTo.getLocalUnqualifiedType() &&
CanonFrom.getLocalQualifiers() != CanonTo.getLocalQualifiers()) {
FromType = ToType;
CanonFrom = CanonTo;
}
SCS.setToType(2, FromType);
if (CanonFrom == CanonTo)
return true;
// If we have not converted the argument type to the parameter type,
// this is a bad conversion sequence, unless we're resolving an overload in C.
if (S.getLangOpts().CPlusPlus || !InOverloadResolution)
return false;
ExprResult ER = ExprResult{From};
Sema::AssignConvertType Conv =
S.CheckSingleAssignmentConstraints(ToType, ER,
/*Diagnose=*/false,
/*DiagnoseCFAudited=*/false,
/*ConvertRHS=*/false);
ImplicitConversionKind SecondConv;
switch (Conv) {
case Sema::Compatible:
SecondConv = ICK_C_Only_Conversion;
break;
// For our purposes, discarding qualifiers is just as bad as using an
// incompatible pointer. Note that an IncompatiblePointer conversion can drop
// qualifiers, as well.
case Sema::CompatiblePointerDiscardsQualifiers:
case Sema::IncompatiblePointer:
case Sema::IncompatiblePointerSign:
SecondConv = ICK_Incompatible_Pointer_Conversion;
break;
default:
return false;
}
// First can only be an lvalue conversion, so we pretend that this was the
// second conversion. First should already be valid from earlier in the
// function.
SCS.Second = SecondConv;
SCS.setToType(1, ToType);
// Third is Identity, because Second should rank us worse than any other
// conversion. This could also be ICK_Qualification, but it's simpler to just
// lump everything in with the second conversion, and we don't gain anything
// from making this ICK_Qualification.
SCS.Third = ICK_Identity;
SCS.setToType(2, ToType);
return true;
}
static bool
IsTransparentUnionStandardConversion(Sema &S, Expr* From,
QualType &ToType,
bool InOverloadResolution,
StandardConversionSequence &SCS,
bool CStyle) {
const RecordType *UT = ToType->getAsUnionType();
if (!UT || !UT->getDecl()->hasAttr<TransparentUnionAttr>())
return false;
// The field to initialize within the transparent union.
RecordDecl *UD = UT->getDecl();
// It's compatible if the expression matches any of the fields.
for (const auto *it : UD->fields()) {
if (IsStandardConversion(S, From, it->getType(), InOverloadResolution, SCS,
CStyle, /*AllowObjCWritebackConversion=*/false)) {
ToType = it->getType();
return true;
}
}
return false;
}
/// IsIntegralPromotion - Determines whether the conversion from the
/// expression From (whose potentially-adjusted type is FromType) to
/// ToType is an integral promotion (C++ 4.5). If so, returns true and
/// sets PromotedType to the promoted type.
bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) {
const BuiltinType *To = ToType->getAs<BuiltinType>();
// All integers are built-in.
if (!To) {
return false;
}
// An rvalue of type char, signed char, unsigned char, short int, or
// unsigned short int can be converted to an rvalue of type int if
// int can represent all the values of the source type; otherwise,
// the source rvalue can be converted to an rvalue of type unsigned
// int (C++ 4.5p1).
if (FromType->isPromotableIntegerType() && !FromType->isBooleanType() &&
!FromType->isEnumeralType()) {
if (// We can promote any signed, promotable integer type to an int
(FromType->isSignedIntegerType() ||
// We can promote any unsigned integer type whose size is
// less than int to an int.
Context.getTypeSize(FromType) < Context.getTypeSize(ToType))) {
return To->getKind() == BuiltinType::Int;
}
return To->getKind() == BuiltinType::UInt;
}
// C++11 [conv.prom]p3:
// A prvalue of an unscoped enumeration type whose underlying type is not
// fixed (7.2) can be converted to an rvalue a prvalue of the first of the
// following types that can represent all the values of the enumeration
// (i.e., the values in the range bmin to bmax as described in 7.2): int,
// unsigned int, long int, unsigned long int, long long int, or unsigned
// long long int. If none of the types in that list can represent all the
// values of the enumeration, an rvalue a prvalue of an unscoped enumeration
// type can be converted to an rvalue a prvalue of the extended integer type
// with lowest integer conversion rank (4.13) greater than the rank of long
// long in which all the values of the enumeration can be represented. If
// there are two such extended types, the signed one is chosen.
// C++11 [conv.prom]p4:
// A prvalue of an unscoped enumeration type whose underlying type is fixed
// can be converted to a prvalue of its underlying type. Moreover, if
// integral promotion can be applied to its underlying type, a prvalue of an
// unscoped enumeration type whose underlying type is fixed can also be
// converted to a prvalue of the promoted underlying type.
if (const EnumType *FromEnumType = FromType->getAs<EnumType>()) {
// C++0x 7.2p9: Note that this implicit enum to int conversion is not
// provided for a scoped enumeration.
if (FromEnumType->getDecl()->isScoped())
return false;
// We can perform an integral promotion to the underlying type of the enum,
// even if that's not the promoted type. Note that the check for promoting
// the underlying type is based on the type alone, and does not consider
// the bitfield-ness of the actual source expression.
if (FromEnumType->getDecl()->isFixed()) {
QualType Underlying = FromEnumType->getDecl()->getIntegerType();
return Context.hasSameUnqualifiedType(Underlying, ToType) ||
IsIntegralPromotion(nullptr, Underlying, ToType);
}
// We have already pre-calculated the promotion type, so this is trivial.
if (ToType->isIntegerType() &&
isCompleteType(From->getBeginLoc(), FromType))
return Context.hasSameUnqualifiedType(
ToType, FromEnumType->getDecl()->getPromotionType());
// C++ [conv.prom]p5:
// If the bit-field has an enumerated type, it is treated as any other
// value of that type for promotion purposes.
//
// ... so do not fall through into the bit-field checks below in C++.
if (getLangOpts().CPlusPlus)
return false;
}
// C++0x [conv.prom]p2:
// A prvalue of type char16_t, char32_t, or wchar_t (3.9.1) can be converted
// to an rvalue a prvalue of the first of the following types that can
// represent all the values of its underlying type: int, unsigned int,
// long int, unsigned long int, long long int, or unsigned long long int.
// If none of the types in that list can represent all the values of its
// underlying type, an rvalue a prvalue of type char16_t, char32_t,
// or wchar_t can be converted to an rvalue a prvalue of its underlying
// type.
if (FromType->isAnyCharacterType() && !FromType->isCharType() &&
ToType->isIntegerType()) {
// Determine whether the type we're converting from is signed or
// unsigned.
bool FromIsSigned = FromType->isSignedIntegerType();
uint64_t FromSize = Context.getTypeSize(FromType);
// The types we'll try to promote to, in the appropriate
// order. Try each of these types.
QualType PromoteTypes[6] = {
Context.IntTy, Context.UnsignedIntTy,
Context.LongTy, Context.UnsignedLongTy ,
Context.LongLongTy, Context.UnsignedLongLongTy
};
for (int Idx = 0; Idx < 6; ++Idx) {
uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]);
if (FromSize < ToSize ||
(FromSize == ToSize &&
FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) {
// We found the type that we can promote to. If this is the
// type we wanted, we have a promotion. Otherwise, no
// promotion.
return Context.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]);
}
}
}
// An rvalue for an integral bit-field (9.6) can be converted to an
// rvalue of type int if int can represent all the values of the
// bit-field; otherwise, it can be converted to unsigned int if
// unsigned int can represent all the values of the bit-field. If
// the bit-field is larger yet, no integral promotion applies to
// it. If the bit-field has an enumerated type, it is treated as any
// other value of that type for promotion purposes (C++ 4.5p3).
// FIXME: We should delay checking of bit-fields until we actually perform the
// conversion.
//
// FIXME: In C, only bit-fields of types _Bool, int, or unsigned int may be
// promoted, per C11 6.3.1.1/2. We promote all bit-fields (including enum
// bit-fields and those whose underlying type is larger than int) for GCC
// compatibility.
if (From) {
if (FieldDecl *MemberDecl = From->getSourceBitField()) {
Optional<llvm::APSInt> BitWidth;
if (FromType->isIntegralType(Context) &&
(BitWidth =
MemberDecl->getBitWidth()->getIntegerConstantExpr(Context))) {
llvm::APSInt ToSize(BitWidth->getBitWidth(), BitWidth->isUnsigned());
ToSize = Context.getTypeSize(ToType);
// Are we promoting to an int from a bitfield that fits in an int?
if (*BitWidth < ToSize ||
(FromType->isSignedIntegerType() && *BitWidth <= ToSize)) {
return To->getKind() == BuiltinType::Int;
}
// Are we promoting to an unsigned int from an unsigned bitfield
// that fits into an unsigned int?
if (FromType->isUnsignedIntegerType() && *BitWidth <= ToSize) {
return To->getKind() == BuiltinType::UInt;
}
return false;
}
}
}
// An rvalue of type bool can be converted to an rvalue of type int,
// with false becoming zero and true becoming one (C++ 4.5p4).
if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) {
return true;
}
return false;
}
/// IsFloatingPointPromotion - Determines whether the conversion from
/// FromType to ToType is a floating point promotion (C++ 4.6). If so,
/// returns true and sets PromotedType to the promoted type.
bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) {
if (const BuiltinType *FromBuiltin = FromType->getAs<BuiltinType>())
if (const BuiltinType *ToBuiltin = ToType->getAs<BuiltinType>()) {
/// An rvalue of type float can be converted to an rvalue of type
/// double. (C++ 4.6p1).
if (FromBuiltin->getKind() == BuiltinType::Float &&
ToBuiltin->getKind() == BuiltinType::Double)
return true;
// C99 6.3.1.5p1:
// When a float is promoted to double or long double, or a
// double is promoted to long double [...].
if (!getLangOpts().CPlusPlus &&
(FromBuiltin->getKind() == BuiltinType::Float ||
FromBuiltin->getKind() == BuiltinType::Double) &&
(ToBuiltin->getKind() == BuiltinType::LongDouble ||
ToBuiltin->getKind() == BuiltinType::Float128 ||
ToBuiltin->getKind() == BuiltinType::Ibm128))
return true;
// Half can be promoted to float.
if (!getLangOpts().NativeHalfType &&
FromBuiltin->getKind() == BuiltinType::Half &&
ToBuiltin->getKind() == BuiltinType::Float)
return true;
}
return false;
}
/// Determine if a conversion is a complex promotion.
///
/// A complex promotion is defined as a complex -> complex conversion
/// where the conversion between the underlying real types is a
/// floating-point or integral promotion.
bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) {
const ComplexType *FromComplex = FromType->getAs<ComplexType>();
if (!FromComplex)
return false;
const ComplexType *ToComplex = ToType->getAs<ComplexType>();
if (!ToComplex)
return false;
return IsFloatingPointPromotion(FromComplex->getElementType(),
ToComplex->getElementType()) ||
IsIntegralPromotion(nullptr, FromComplex->getElementType(),
ToComplex->getElementType());
}
/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from
/// the pointer type FromPtr to a pointer to type ToPointee, with the
/// same type qualifiers as FromPtr has on its pointee type. ToType,
/// if non-empty, will be a pointer to ToType that may or may not have
/// the right set of qualifiers on its pointee.
///
static QualType
BuildSimilarlyQualifiedPointerType(const Type *FromPtr,
QualType ToPointee, QualType ToType,
ASTContext &Context,
bool StripObjCLifetime = false) {
assert((FromPtr->getTypeClass() == Type::Pointer ||
FromPtr->getTypeClass() == Type::ObjCObjectPointer) &&
"Invalid similarly-qualified pointer type");
/// Conversions to 'id' subsume cv-qualifier conversions.
if (ToType->isObjCIdType() || ToType->isObjCQualifiedIdType())
return ToType.getUnqualifiedType();
QualType CanonFromPointee
= Context.getCanonicalType(FromPtr->getPointeeType());
QualType CanonToPointee = Context.getCanonicalType(ToPointee);
Qualifiers Quals = CanonFromPointee.getQualifiers();
if (StripObjCLifetime)
Quals.removeObjCLifetime();
// Exact qualifier match -> return the pointer type we're converting to.
if (CanonToPointee.getLocalQualifiers() == Quals) {
// ToType is exactly what we need. Return it.
if (!ToType.isNull())
return ToType.getUnqualifiedType();
// Build a pointer to ToPointee. It has the right qualifiers
// already.
if (isa<ObjCObjectPointerType>(ToType))
return Context.getObjCObjectPointerType(ToPointee);
return Context.getPointerType(ToPointee);
}
// Just build a canonical type that has the right qualifiers.
QualType QualifiedCanonToPointee
= Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), Quals);
if (isa<ObjCObjectPointerType>(ToType))
return Context.getObjCObjectPointerType(QualifiedCanonToPointee);
return Context.getPointerType(QualifiedCanonToPointee);
}
static bool isNullPointerConstantForConversion(Expr *Expr,
bool InOverloadResolution,
ASTContext &Context) {
// Handle value-dependent integral null pointer constants correctly.
// http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903
if (Expr->isValueDependent() && !Expr->isTypeDependent() &&
Expr->getType()->isIntegerType() && !Expr->getType()->isEnumeralType())
return !InOverloadResolution;
return Expr->isNullPointerConstant(Context,
InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
: Expr::NPC_ValueDependentIsNull);
}
/// IsPointerConversion - Determines whether the conversion of the
/// expression From, which has the (possibly adjusted) type FromType,
/// can be converted to the type ToType via a pointer conversion (C++
/// 4.10). If so, returns true and places the converted type (that
/// might differ from ToType in its cv-qualifiers at some level) into
/// ConvertedType.
///
/// This routine also supports conversions to and from block pointers
/// and conversions with Objective-C's 'id', 'id<protocols...>', and
/// pointers to interfaces. FIXME: Once we've determined the
/// appropriate overloading rules for Objective-C, we may want to
/// split the Objective-C checks into a different routine; however,
/// GCC seems to consider all of these conversions to be pointer
/// conversions, so for now they live here. IncompatibleObjC will be
/// set if the conversion is an allowed Objective-C conversion that
/// should result in a warning.
bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
bool InOverloadResolution,
QualType& ConvertedType,
bool &IncompatibleObjC) {
IncompatibleObjC = false;
if (isObjCPointerConversion(FromType, ToType, ConvertedType,
IncompatibleObjC))
return true;
// Conversion from a null pointer constant to any Objective-C pointer type.
if (ToType->isObjCObjectPointerType() &&
isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
ConvertedType = ToType;
return true;
}
// Blocks: Block pointers can be converted to void*.
if (FromType->isBlockPointerType() && ToType->isPointerType() &&
ToType->castAs<PointerType>()->getPointeeType()->isVoidType()) {
ConvertedType = ToType;
return true;
}
// Blocks: A null pointer constant can be converted to a block
// pointer type.
if (ToType->isBlockPointerType() &&
isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
ConvertedType = ToType;
return true;
}
// If the left-hand-side is nullptr_t, the right side can be a null
// pointer constant.
if (ToType->isNullPtrType() &&
isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
ConvertedType = ToType;
return true;
}
const PointerType* ToTypePtr = ToType->getAs<PointerType>();
if (!ToTypePtr)
return false;
// A null pointer constant can be converted to a pointer type (C++ 4.10p1).
if (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
ConvertedType = ToType;
return true;
}
// Beyond this point, both types need to be pointers
// , including objective-c pointers.
QualType ToPointeeType = ToTypePtr->getPointeeType();
if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType() &&
!getLangOpts().ObjCAutoRefCount) {
ConvertedType = BuildSimilarlyQualifiedPointerType(
FromType->getAs<ObjCObjectPointerType>(),
ToPointeeType,
ToType, Context);
return true;
}
const PointerType *FromTypePtr = FromType->getAs<PointerType>();
if (!FromTypePtr)
return false;
QualType FromPointeeType = FromTypePtr->getPointeeType();
// If the unqualified pointee types are the same, this can't be a
// pointer conversion, so don't do all of the work below.
if (Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType))
return false;
// An rvalue of type "pointer to cv T," where T is an object type,
// can be converted to an rvalue of type "pointer to cv void" (C++
// 4.10p2).
if (FromPointeeType->isIncompleteOrObjectType() &&
ToPointeeType->isVoidType()) {
ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
ToPointeeType,
ToType, Context,
/*StripObjCLifetime=*/true);
return true;
}
// MSVC allows implicit function to void* type conversion.
if (getLangOpts().MSVCCompat && FromPointeeType->isFunctionType() &&
ToPointeeType->isVoidType()) {
ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
ToPointeeType,
ToType, Context);
return true;
}
// When we're overloading in C, we allow a special kind of pointer
// conversion for compatible-but-not-identical pointee types.
if (!getLangOpts().CPlusPlus &&
Context.typesAreCompatible(FromPointeeType, ToPointeeType)) {
ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
ToPointeeType,
ToType, Context);
return true;
}
// C++ [conv.ptr]p3:
//
// An rvalue of type "pointer to cv D," where D is a class type,
// can be converted to an rvalue of type "pointer to cv B," where
// B is a base class (clause 10) of D. If B is an inaccessible
// (clause 11) or ambiguous (10.2) base class of D, a program that
// necessitates this conversion is ill-formed. The result of the
// conversion is a pointer to the base class sub-object of the
// derived class object. The null pointer value is converted to
// the null pointer value of the destination type.
//
// Note that we do not check for ambiguity or inaccessibility
// here. That is handled by CheckPointerConversion.
if (getLangOpts().CPlusPlus && FromPointeeType->isRecordType() &&
ToPointeeType->isRecordType() &&
!Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType) &&
IsDerivedFrom(From->getBeginLoc(), FromPointeeType, ToPointeeType)) {
ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
ToPointeeType,
ToType, Context);
return true;
}
if (FromPointeeType->isVectorType() && ToPointeeType->isVectorType() &&
Context.areCompatibleVectorTypes(FromPointeeType, ToPointeeType)) {
ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
ToPointeeType,
ToType, Context);
return true;
}
return false;
}
/// Adopt the given qualifiers for the given type.
static QualType AdoptQualifiers(ASTContext &Context, QualType T, Qualifiers Qs){
Qualifiers TQs = T.getQualifiers();
// Check whether qualifiers already match.
if (TQs == Qs)
return T;
if (Qs.compatiblyIncludes(TQs))
return Context.getQualifiedType(T, Qs);
return Context.getQualifiedType(T.getUnqualifiedType(), Qs);
}
/// isObjCPointerConversion - Determines whether this is an
/// Objective-C pointer conversion. Subroutine of IsPointerConversion,
/// with the same arguments and return values.
bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType,
QualType& ConvertedType,
bool &IncompatibleObjC) {
if (!getLangOpts().ObjC)
return false;
// The set of qualifiers on the type we're converting from.
Qualifiers FromQualifiers = FromType.getQualifiers();
// First, we handle all conversions on ObjC object pointer types.
const ObjCObjectPointerType* ToObjCPtr =
ToType->getAs<ObjCObjectPointerType>();
const ObjCObjectPointerType *FromObjCPtr =
FromType->getAs<ObjCObjectPointerType>();
if (ToObjCPtr && FromObjCPtr) {
// If the pointee types are the same (ignoring qualifications),
// then this is not a pointer conversion.
if (Context.hasSameUnqualifiedType(ToObjCPtr->getPointeeType(),
FromObjCPtr->getPointeeType()))
return false;
// Conversion between Objective-C pointers.
if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) {
const ObjCInterfaceType* LHS = ToObjCPtr->getInterfaceType();
const ObjCInterfaceType* RHS = FromObjCPtr->getInterfaceType();
if (getLangOpts().CPlusPlus && LHS && RHS &&
!ToObjCPtr->getPointeeType().isAtLeastAsQualifiedAs(
FromObjCPtr->getPointeeType()))
return false;
ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
ToObjCPtr->getPointeeType(),
ToType, Context);
ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
return true;
}
if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) {
// Okay: this is some kind of implicit downcast of Objective-C
// interfaces, which is permitted. However, we're going to
// complain about it.
IncompatibleObjC = true;
ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
ToObjCPtr->getPointeeType(),
ToType, Context);
ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
return true;
}
}
// Beyond this point, both types need to be C pointers or block pointers.
QualType ToPointeeType;
if (const PointerType *ToCPtr = ToType->getAs<PointerType>())
ToPointeeType = ToCPtr->getPointeeType();
else if (const BlockPointerType *ToBlockPtr =
ToType->getAs<BlockPointerType>()) {
// Objective C++: We're able to convert from a pointer to any object
// to a block pointer type.
if (FromObjCPtr && FromObjCPtr->isObjCBuiltinType()) {
ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
return true;
}
ToPointeeType = ToBlockPtr->getPointeeType();
}
else if (FromType->getAs<BlockPointerType>() &&
ToObjCPtr && ToObjCPtr->isObjCBuiltinType()) {
// Objective C++: We're able to convert from a block pointer type to a
// pointer to any object.
ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
return true;
}
else
return false;
QualType FromPointeeType;
if (const PointerType *FromCPtr = FromType->getAs<PointerType>())
FromPointeeType = FromCPtr->getPointeeType();
else if (const BlockPointerType *FromBlockPtr =
FromType->getAs<BlockPointerType>())
FromPointeeType = FromBlockPtr->getPointeeType();
else
return false;
// If we have pointers to pointers, recursively check whether this
// is an Objective-C conversion.
if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() &&
isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
IncompatibleObjC)) {
// We always complain about this conversion.
IncompatibleObjC = true;
ConvertedType = Context.getPointerType(ConvertedType);
ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
return true;
}
// Allow conversion of pointee being objective-c pointer to another one;
// as in I* to id.
if (FromPointeeType->getAs<ObjCObjectPointerType>() &&
ToPointeeType->getAs<ObjCObjectPointerType>() &&
isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
IncompatibleObjC)) {
ConvertedType = Context.getPointerType(ConvertedType);
ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
return true;
}
// If we have pointers to functions or blocks, check whether the only
// differences in the argument and result types are in Objective-C
// pointer conversions. If so, we permit the conversion (but
// complain about it).
const FunctionProtoType *FromFunctionType
= FromPointeeType->getAs<FunctionProtoType>();
const FunctionProtoType *ToFunctionType
= ToPointeeType->getAs<FunctionProtoType>();
if (FromFunctionType && ToFunctionType) {
// If the function types are exactly the same, this isn't an
// Objective-C pointer conversion.
if (Context.getCanonicalType(FromPointeeType)
== Context.getCanonicalType(ToPointeeType))
return false;
// Perform the quick checks that will tell us whether these
// function types are obviously different.
if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
FromFunctionType->isVariadic() != ToFunctionType->isVariadic() ||
FromFunctionType->getMethodQuals() != ToFunctionType->getMethodQuals())
return false;
bool HasObjCConversion = false;
if (Context.getCanonicalType(FromFunctionType->getReturnType()) ==
Context.getCanonicalType(ToFunctionType->getReturnType())) {
// Okay, the types match exactly. Nothing to do.
} else if (isObjCPointerConversion(FromFunctionType->getReturnType(),
ToFunctionType->getReturnType(),
ConvertedType, IncompatibleObjC)) {
// Okay, we have an Objective-C pointer conversion.
HasObjCConversion = true;
} else {
// Function types are too different. Abort.
return false;
}
// Check argument types.
for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
ArgIdx != NumArgs; ++ArgIdx) {
QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
if (Context.getCanonicalType(FromArgType)
== Context.getCanonicalType(ToArgType)) {
// Okay, the types match exactly. Nothing to do.
} else if (isObjCPointerConversion(FromArgType, ToArgType,
ConvertedType, IncompatibleObjC)) {
// Okay, we have an Objective-C pointer conversion.
HasObjCConversion = true;
} else {
// Argument types are too different. Abort.
return false;
}
}
if (HasObjCConversion) {
// We had an Objective-C conversion. Allow this pointer
// conversion, but complain about it.
ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
IncompatibleObjC = true;
return true;
}
}
return false;
}
/// Determine whether this is an Objective-C writeback conversion,
/// used for parameter passing when performing automatic reference counting.
///
/// \param FromType The type we're converting form.
///
/// \param ToType The type we're converting to.
///
/// \param ConvertedType The type that will be produced after applying
/// this conversion.
bool Sema::isObjCWritebackConversion(QualType FromType, QualType ToType,
QualType &ConvertedType) {
if (!getLangOpts().ObjCAutoRefCount ||
Context.hasSameUnqualifiedType(FromType, ToType))
return false;
// Parameter must be a pointer to __autoreleasing (with no other qualifiers).
QualType ToPointee;
if (const PointerType *ToPointer = ToType->getAs<PointerType>())
ToPointee = ToPointer->getPointeeType();
else
return false;
Qualifiers ToQuals = ToPointee.getQualifiers();
if (!ToPointee->isObjCLifetimeType() ||
ToQuals.getObjCLifetime() != Qualifiers::OCL_Autoreleasing ||
!ToQuals.withoutObjCLifetime().empty())
return false;
// Argument must be a pointer to __strong to __weak.
QualType FromPointee;
if (const PointerType *FromPointer = FromType->getAs<PointerType>())
FromPointee = FromPointer->getPointeeType();
else
return false;
Qualifiers FromQuals = FromPointee.getQualifiers();
if (!FromPointee->isObjCLifetimeType() ||
(FromQuals.getObjCLifetime() != Qualifiers::OCL_Strong &&
FromQuals.getObjCLifetime() != Qualifiers::OCL_Weak))
return false;
// Make sure that we have compatible qualifiers.
FromQuals.setObjCLifetime(Qualifiers::OCL_Autoreleasing);
if (!ToQuals.compatiblyIncludes(FromQuals))
return false;
// Remove qualifiers from the pointee type we're converting from; they
// aren't used in the compatibility check belong, and we'll be adding back
// qualifiers (with __autoreleasing) if the compatibility check succeeds.
FromPointee = FromPointee.getUnqualifiedType();
// The unqualified form of the pointee types must be compatible.
ToPointee = ToPointee.getUnqualifiedType();
bool IncompatibleObjC;
if (Context.typesAreCompatible(FromPointee, ToPointee))
FromPointee = ToPointee;
else if (!isObjCPointerConversion(FromPointee, ToPointee, FromPointee,
IncompatibleObjC))
return false;
/// Construct the type we're converting to, which is a pointer to
/// __autoreleasing pointee.
FromPointee = Context.getQualifiedType(FromPointee, FromQuals);
ConvertedType = Context.getPointerType(FromPointee);
return true;
}
bool Sema::IsBlockPointerConversion(QualType FromType, QualType ToType,
QualType& ConvertedType) {
QualType ToPointeeType;
if (const BlockPointerType *ToBlockPtr =
ToType->getAs<BlockPointerType>())
ToPointeeType = ToBlockPtr->getPointeeType();
else
return false;
QualType FromPointeeType;
if (const BlockPointerType *FromBlockPtr =
FromType->getAs<BlockPointerType>())
FromPointeeType = FromBlockPtr->getPointeeType();
else
return false;
// We have pointer to blocks, check whether the only
// differences in the argument and result types are in Objective-C
// pointer conversions. If so, we permit the conversion.
const FunctionProtoType *FromFunctionType
= FromPointeeType->getAs<FunctionProtoType>();
const FunctionProtoType *ToFunctionType
= ToPointeeType->getAs<FunctionProtoType>();
if (!FromFunctionType || !ToFunctionType)
return false;
if (Context.hasSameType(FromPointeeType, ToPointeeType))
return true;
// Perform the quick checks that will tell us whether these
// function types are obviously different.
if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
FromFunctionType->isVariadic() != ToFunctionType->isVariadic())
return false;
FunctionType::ExtInfo FromEInfo = FromFunctionType->getExtInfo();
FunctionType::ExtInfo ToEInfo = ToFunctionType->getExtInfo();
if (FromEInfo != ToEInfo)
return false;
bool IncompatibleObjC = false;
if (Context.hasSameType(FromFunctionType->getReturnType(),
ToFunctionType->getReturnType())) {
// Okay, the types match exactly. Nothing to do.
} else {
QualType RHS = FromFunctionType->getReturnType();
QualType LHS = ToFunctionType->getReturnType();
if ((!getLangOpts().CPlusPlus || !RHS->isRecordType()) &&
!RHS.hasQualifiers() && LHS.hasQualifiers())
LHS = LHS.getUnqualifiedType();
if (Context.hasSameType(RHS,LHS)) {
// OK exact match.
} else if (isObjCPointerConversion(RHS, LHS,
ConvertedType, IncompatibleObjC)) {
if (IncompatibleObjC)
return false;
// Okay, we have an Objective-C pointer conversion.
}
else
return false;
}
// Check argument types.
for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
ArgIdx != NumArgs; ++ArgIdx) {
IncompatibleObjC = false;
QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
if (Context.hasSameType(FromArgType, ToArgType)) {
// Okay, the types match exactly. Nothing to do.
} else if (isObjCPointerConversion(ToArgType, FromArgType,
ConvertedType, IncompatibleObjC)) {
if (IncompatibleObjC)
return false;
// Okay, we have an Objective-C pointer conversion.
} else
// Argument types are too different. Abort.
return false;
}
SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos;
bool CanUseToFPT, CanUseFromFPT;
if (!Context.mergeExtParameterInfo(ToFunctionType, FromFunctionType,
CanUseToFPT, CanUseFromFPT,
NewParamInfos))
return false;
ConvertedType = ToType;
return true;
}
enum {
ft_default,
ft_different_class,
ft_parameter_arity,
ft_parameter_mismatch,
ft_return_type,
ft_qualifer_mismatch,
ft_noexcept
};
/// Attempts to get the FunctionProtoType from a Type. Handles
/// MemberFunctionPointers properly.
static const FunctionProtoType *tryGetFunctionProtoType(QualType FromType) {
if (auto *FPT = FromType->getAs<FunctionProtoType>())
return FPT;
if (auto *MPT = FromType->getAs<MemberPointerType>())
return MPT->getPointeeType()->getAs<FunctionProtoType>();
return nullptr;
}
/// HandleFunctionTypeMismatch - Gives diagnostic information for differeing
/// function types. Catches different number of parameter, mismatch in
/// parameter types, and different return types.
void Sema::HandleFunctionTypeMismatch(PartialDiagnostic &PDiag,
QualType FromType, QualType ToType) {
// If either type is not valid, include no extra info.
if (FromType.isNull() || ToType.isNull()) {
PDiag << ft_default;
return;
}
// Get the function type from the pointers.
if (FromType->isMemberPointerType() && ToType->isMemberPointerType()) {
const auto *FromMember = FromType->castAs<MemberPointerType>(),
*ToMember = ToType->castAs<MemberPointerType>();
if (!Context.hasSameType(FromMember->getClass(), ToMember->getClass())) {
PDiag << ft_different_class << QualType(ToMember->getClass(), 0)
<< QualType(FromMember->getClass(), 0);
return;
}
FromType = FromMember->getPointeeType();
ToType = ToMember->getPointeeType();
}
if (FromType->isPointerType())
FromType = FromType->getPointeeType();
if (ToType->isPointerType())
ToType = ToType->getPointeeType();
// Remove references.
FromType = FromType.getNonReferenceType();
ToType = ToType.getNonReferenceType();
// Don't print extra info for non-specialized template functions.
if (FromType->isInstantiationDependentType() &&
!FromType->getAs<TemplateSpecializationType>()) {
PDiag << ft_default;
return;
}
// No extra info for same types.
if (Context.hasSameType(FromType, ToType)) {
PDiag << ft_default;
return;
}
const FunctionProtoType *FromFunction = tryGetFunctionProtoType(FromType),
*ToFunction = tryGetFunctionProtoType(ToType);
// Both types need to be function types.
if (!FromFunction || !ToFunction) {
PDiag << ft_default;
return;
}
if (FromFunction->getNumParams() != ToFunction->getNumParams()) {
PDiag << ft_parameter_arity << ToFunction->getNumParams()
<< FromFunction->getNumParams();
return;
}
// Handle different parameter types.
unsigned ArgPos;
if (!FunctionParamTypesAreEqual(FromFunction, ToFunction, &ArgPos)) {
PDiag << ft_parameter_mismatch << ArgPos + 1
<< ToFunction->getParamType(ArgPos)
<< FromFunction->getParamType(ArgPos);
return;
}
// Handle different return type.
if (!Context.hasSameType(FromFunction->getReturnType(),
ToFunction->getReturnType())) {
PDiag << ft_return_type << ToFunction->getReturnType()
<< FromFunction->getReturnType();
return;
}
if (FromFunction->getMethodQuals() != ToFunction->getMethodQuals()) {
PDiag << ft_qualifer_mismatch << ToFunction->getMethodQuals()
<< FromFunction->getMethodQuals();
return;
}
// Handle exception specification differences on canonical type (in C++17
// onwards).
if (cast<FunctionProtoType>(FromFunction->getCanonicalTypeUnqualified())
->isNothrow() !=
cast<FunctionProtoType>(ToFunction->getCanonicalTypeUnqualified())
->isNothrow()) {
PDiag << ft_noexcept;
return;
}
// Unable to find a difference, so add no extra info.
PDiag << ft_default;
}
/// FunctionParamTypesAreEqual - This routine checks two function proto types
/// for equality of their argument types. Caller has already checked that
/// they have same number of arguments. If the parameters are different,
/// ArgPos will have the parameter index of the first different parameter.
bool Sema::FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
const FunctionProtoType *NewType,
unsigned *ArgPos) {
for (FunctionProtoType::param_type_iterator O = OldType->param_type_begin(),
N = NewType->param_type_begin(),
E = OldType->param_type_end();
O && (O != E); ++O, ++N) {
// Ignore address spaces in pointee type. This is to disallow overloading
// on __ptr32/__ptr64 address spaces.
QualType Old = Context.removePtrSizeAddrSpace(O->getUnqualifiedType());
QualType New = Context.removePtrSizeAddrSpace(N->getUnqualifiedType());
if (!Context.hasSameType(Old, New)) {
if (ArgPos)
*ArgPos = O - OldType->param_type_begin();
return false;
}
}
return true;
}
/// CheckPointerConversion - Check the pointer conversion from the
/// expression From to the type ToType. This routine checks for
/// ambiguous or inaccessible derived-to-base pointer
/// conversions for which IsPointerConversion has already returned
/// true. It returns true and produces a diagnostic if there was an
/// error, or returns false otherwise.
bool Sema::CheckPointerConversion(Expr *From, QualType ToType,
CastKind &Kind,
CXXCastPath& BasePath,
bool IgnoreBaseAccess,
bool Diagnose) {
QualType FromType = From->getType();
bool IsCStyleOrFunctionalCast = IgnoreBaseAccess;
Kind = CK_BitCast;
if (Diagnose && !IsCStyleOrFunctionalCast && !FromType->isAnyPointerType() &&
From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull) ==
Expr::NPCK_ZeroExpression) {
if (Context.hasSameUnqualifiedType(From->getType(), Context.BoolTy))
DiagRuntimeBehavior(From->getExprLoc(), From,
PDiag(diag::warn_impcast_bool_to_null_pointer)
<< ToType << From->getSourceRange());
else if (!isUnevaluatedContext())
Diag(From->getExprLoc(), diag::warn_non_literal_null_pointer)
<< ToType << From->getSourceRange();
}
if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) {
if (const PointerType *FromPtrType = FromType->getAs<PointerType>()) {
QualType FromPointeeType = FromPtrType->getPointeeType(),
ToPointeeType = ToPtrType->getPointeeType();
if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() &&
!Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) {
// We must have a derived-to-base conversion. Check an
// ambiguous or inaccessible conversion.
unsigned InaccessibleID = 0;
unsigned AmbiguousID = 0;
if (Diagnose) {
InaccessibleID = diag::err_upcast_to_inaccessible_base;
AmbiguousID = diag::err_ambiguous_derived_to_base_conv;
}
if (CheckDerivedToBaseConversion(
FromPointeeType, ToPointeeType, InaccessibleID, AmbiguousID,
From->getExprLoc(), From->getSourceRange(), DeclarationName(),
&BasePath, IgnoreBaseAccess))
return true;
// The conversion was successful.
Kind = CK_DerivedToBase;
}
if (Diagnose && !IsCStyleOrFunctionalCast &&
FromPointeeType->isFunctionType() && ToPointeeType->isVoidType()) {
assert(getLangOpts().MSVCCompat &&
"this should only be possible with MSVCCompat!");
Diag(From->getExprLoc(), diag::ext_ms_impcast_fn_obj)
<< From->getSourceRange();
}
}
} else if (const ObjCObjectPointerType *ToPtrType =
ToType->getAs<ObjCObjectPointerType>()) {
if (const ObjCObjectPointerType *FromPtrType =
FromType->getAs<ObjCObjectPointerType>()) {
// Objective-C++ conversions are always okay.
// FIXME: We should have a different class of conversions for the
// Objective-C++ implicit conversions.
if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType())
return false;
} else if (FromType->isBlockPointerType()) {
Kind = CK_BlockPointerToObjCPointerCast;
} else {
Kind = CK_CPointerToObjCPointerCast;
}
} else if (ToType->isBlockPointerType()) {
if (!FromType->isBlockPointerType())
Kind = CK_AnyPointerToBlockPointerCast;
}
// We shouldn't fall into this case unless it's valid for other
// reasons.
if (From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull))
Kind = CK_NullToPointer;
return false;
}
/// IsMemberPointerConversion - Determines whether the conversion of the
/// expression From, which has the (possibly adjusted) type FromType, can be
/// converted to the type ToType via a member pointer conversion (C++ 4.11).
/// If so, returns true and places the converted type (that might differ from
/// ToType in its cv-qualifiers at some level) into ConvertedType.
bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType,
QualType ToType,
bool InOverloadResolution,
QualType &ConvertedType) {
const MemberPointerType *ToTypePtr = ToType->getAs<MemberPointerType>();
if (!ToTypePtr)
return false;
// A null pointer constant can be converted to a member pointer (C++ 4.11p1)
if (From->isNullPointerConstant(Context,
InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
: Expr::NPC_ValueDependentIsNull)) {
ConvertedType = ToType;
return true;
}
// Otherwise, both types have to be member pointers.
const MemberPointerType *FromTypePtr = FromType->getAs<MemberPointerType>();
if (!FromTypePtr)
return false;
// A pointer to member of B can be converted to a pointer to member of D,
// where D is derived from B (C++ 4.11p2).
QualType FromClass(FromTypePtr->getClass(), 0);
QualType ToClass(ToTypePtr->getClass(), 0);
if (!Context.hasSameUnqualifiedType(FromClass, ToClass) &&
IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass)) {
ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(),
ToClass.getTypePtr());
return true;
}
return false;
}
/// CheckMemberPointerConversion - Check the member pointer conversion from the
/// expression From to the type ToType. This routine checks for ambiguous or
/// virtual or inaccessible base-to-derived member pointer conversions
/// for which IsMemberPointerConversion has already returned true. It returns
/// true and produces a diagnostic if there was an error, or returns false
/// otherwise.
bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType,
CastKind &Kind,
CXXCastPath &BasePath,
bool IgnoreBaseAccess) {
QualType FromType = From->getType();
const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>();
if (!FromPtrType) {
// This must be a null pointer to member pointer conversion
assert(From->isNullPointerConstant(Context,
Expr::NPC_ValueDependentIsNull) &&
"Expr must be null pointer constant!");
Kind = CK_NullToMemberPointer;
return false;
}
const MemberPointerType *ToPtrType = ToType->getAs<MemberPointerType>();
assert(ToPtrType && "No member pointer cast has a target type "
"that is not a member pointer.");
QualType FromClass = QualType(FromPtrType->getClass(), 0);
QualType ToClass = QualType(ToPtrType->getClass(), 0);
// FIXME: What about dependent types?
assert(FromClass->isRecordType() && "Pointer into non-class.");
assert(ToClass->isRecordType() && "Pointer into non-class.");
CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
/*DetectVirtual=*/true);
bool DerivationOkay =
IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass, Paths);
assert(DerivationOkay &&
"Should not have been called if derivation isn't OK.");
(void)DerivationOkay;
if (Paths.isAmbiguous(Context.getCanonicalType(FromClass).
getUnqualifiedType())) {
std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths);
Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv)
<< 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange();
return true;
}
if (const RecordType *VBase = Paths.getDetectedVirtual()) {
Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual)
<< FromClass << ToClass << QualType(VBase, 0)
<< From->getSourceRange();
return true;
}
if (!IgnoreBaseAccess)
CheckBaseClassAccess(From->getExprLoc(), FromClass, ToClass,
Paths.front(),
diag::err_downcast_from_inaccessible_base);
// Must be a base to derived member conversion.
BuildBasePathArray(Paths, BasePath);
Kind = CK_BaseToDerivedMemberPointer;
return false;
}
/// Determine whether the lifetime conversion between the two given
/// qualifiers sets is nontrivial.
static bool isNonTrivialObjCLifetimeConversion(Qualifiers FromQuals,
Qualifiers ToQuals) {
// Converting anything to const __unsafe_unretained is trivial.
if (ToQuals.hasConst() &&
ToQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone)
return false;
return true;
}
/// Perform a single iteration of the loop for checking if a qualification
/// conversion is valid.
///
/// Specifically, check whether any change between the qualifiers of \p
/// FromType and \p ToType is permissible, given knowledge about whether every
/// outer layer is const-qualified.
static bool isQualificationConversionStep(QualType FromType, QualType ToType,
bool CStyle, bool IsTopLevel,
bool &PreviousToQualsIncludeConst,
bool &ObjCLifetimeConversion) {
Qualifiers FromQuals = FromType.getQualifiers();
Qualifiers ToQuals = ToType.getQualifiers();
// Ignore __unaligned qualifier if this type is void.
if (ToType.getUnqualifiedType()->isVoidType())
FromQuals.removeUnaligned();
// Objective-C ARC:
// Check Objective-C lifetime conversions.
if (FromQuals.getObjCLifetime() != ToQuals.getObjCLifetime()) {
if (ToQuals.compatiblyIncludesObjCLifetime(FromQuals)) {
if (isNonTrivialObjCLifetimeConversion(FromQuals, ToQuals))
ObjCLifetimeConversion = true;
FromQuals.removeObjCLifetime();
ToQuals.removeObjCLifetime();
} else {
// Qualification conversions cannot cast between different
// Objective-C lifetime qualifiers.
return false;
}
}
// Allow addition/removal of GC attributes but not changing GC attributes.
if (FromQuals.getObjCGCAttr() != ToQuals.getObjCGCAttr() &&
(!FromQuals.hasObjCGCAttr() || !ToQuals.hasObjCGCAttr())) {
FromQuals.removeObjCGCAttr();
ToQuals.removeObjCGCAttr();
}
// -- for every j > 0, if const is in cv 1,j then const is in cv
// 2,j, and similarly for volatile.
if (!CStyle && !ToQuals.compatiblyIncludes(FromQuals))
return false;
// If address spaces mismatch:
// - in top level it is only valid to convert to addr space that is a
// superset in all cases apart from C-style casts where we allow
// conversions between overlapping address spaces.
// - in non-top levels it is not a valid conversion.
if (ToQuals.getAddressSpace() != FromQuals.getAddressSpace() &&
(!IsTopLevel ||
!(ToQuals.isAddressSpaceSupersetOf(FromQuals) ||
(CStyle && FromQuals.isAddressSpaceSupersetOf(ToQuals)))))
return false;
// -- if the cv 1,j and cv 2,j are different, then const is in
// every cv for 0 < k < j.
if (!CStyle && FromQuals.getCVRQualifiers() != ToQuals.getCVRQualifiers() &&
!PreviousToQualsIncludeConst)
return false;
// The following wording is from C++20, where the result of the conversion
// is T3, not T2.
// -- if [...] P1,i [...] is "array of unknown bound of", P3,i is
// "array of unknown bound of"
if (FromType->isIncompleteArrayType() && !ToType->isIncompleteArrayType())
return false;
// -- if the resulting P3,i is different from P1,i [...], then const is
// added to every cv 3_k for 0 < k < i.
if (!CStyle && FromType->isConstantArrayType() &&
ToType->isIncompleteArrayType() && !PreviousToQualsIncludeConst)
return false;
// Keep track of whether all prior cv-qualifiers in the "to" type
// include const.
PreviousToQualsIncludeConst =
PreviousToQualsIncludeConst && ToQuals.hasConst();
return true;
}
/// IsQualificationConversion - Determines whether the conversion from
/// an rvalue of type FromType to ToType is a qualification conversion
/// (C++ 4.4).
///
/// \param ObjCLifetimeConversion Output parameter that will be set to indicate
/// when the qualification conversion involves a change in the Objective-C
/// object lifetime.
bool
Sema::IsQualificationConversion(QualType FromType, QualType ToType,
bool CStyle, bool &ObjCLifetimeConversion) {
FromType = Context.getCanonicalType(FromType);
ToType = Context.getCanonicalType(ToType);
ObjCLifetimeConversion = false;
// If FromType and ToType are the same type, this is not a
// qualification conversion.
if (FromType.getUnqualifiedType() == ToType.getUnqualifiedType())
return false;
// (C++ 4.4p4):
// A conversion can add cv-qualifiers at levels other than the first
// in multi-level pointers, subject to the following rules: [...]
bool PreviousToQualsIncludeConst = true;
bool UnwrappedAnyPointer = false;
while (Context.UnwrapSimilarTypes(FromType, ToType)) {
if (!isQualificationConversionStep(
FromType, ToType, CStyle, !UnwrappedAnyPointer,
PreviousToQualsIncludeConst, ObjCLifetimeConversion))
return false;
UnwrappedAnyPointer = true;
}
// We are left with FromType and ToType being the pointee types
// after unwrapping the original FromType and ToType the same number
// of times. If we unwrapped any pointers, and if FromType and
// ToType have the same unqualified type (since we checked
// qualifiers above), then this is a qualification conversion.
return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType);
}
/// - Determine whether this is a conversion from a scalar type to an
/// atomic type.
///
/// If successful, updates \c SCS's second and third steps in the conversion
/// sequence to finish the conversion.
static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
bool InOverloadResolution,
StandardConversionSequence &SCS,
bool CStyle) {
const AtomicType *ToAtomic = ToType->getAs<AtomicType>();
if (!ToAtomic)
return false;
StandardConversionSequence InnerSCS;
if (!IsStandardConversion(S, From, ToAtomic->getValueType(),
InOverloadResolution, InnerSCS,
CStyle, /*AllowObjCWritebackConversion=*/false))
return false;
SCS.Second = InnerSCS.Second;
SCS.setToType(1, InnerSCS.getToType(1));
SCS.Third = InnerSCS.Third;
SCS.QualificationIncludesObjCLifetime
= InnerSCS.QualificationIncludesObjCLifetime;
SCS.setToType(2, InnerSCS.getToType(2));
return true;
}
static bool isFirstArgumentCompatibleWithType(ASTContext &Context,
CXXConstructorDecl *Constructor,
QualType Type) {
const auto *CtorType = Constructor->getType()->castAs<FunctionProtoType>();
if (CtorType->getNumParams() > 0) {
QualType FirstArg = CtorType->getParamType(0);
if (Context.hasSameUnqualifiedType(Type, FirstArg.getNonReferenceType()))
return true;
}
return false;
}
static OverloadingResult
IsInitializerListConstructorConversion(Sema &S, Expr *From, QualType ToType,
CXXRecordDecl *To,
UserDefinedConversionSequence &User,
OverloadCandidateSet &CandidateSet,
bool AllowExplicit) {
CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
for (auto *D : S.LookupConstructors(To)) {
auto Info = getConstructorInfo(D);
if (!Info)
continue;
bool Usable = !Info.Constructor->isInvalidDecl() &&
S.isInitListConstructor(Info.Constructor);
if (Usable) {
bool SuppressUserConversions = false;
if (Info.ConstructorTmpl)
S.AddTemplateOverloadCandidate(Info.ConstructorTmpl, Info.FoundDecl,
/*ExplicitArgs*/ nullptr, From,
CandidateSet, SuppressUserConversions,
/*PartialOverloading*/ false,
AllowExplicit);
else
S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, From,
CandidateSet, SuppressUserConversions,
/*PartialOverloading*/ false, AllowExplicit);
}
}
bool HadMultipleCandidates = (CandidateSet.size() > 1);
OverloadCandidateSet::iterator Best;
switch (auto Result =
CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
case OR_Deleted:
case OR_Success: {
// Record the standard conversion we used and the conversion function.
CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Best->Function);
QualType ThisType = Constructor->getThisType();
// Initializer lists don't have conversions as such.
User.Before.setAsIdentityConversion();
User.HadMultipleCandidates = HadMultipleCandidates;
User.ConversionFunction = Constructor;
User.FoundConversionFunction = Best->FoundDecl;
User.After.setAsIdentityConversion();
User.After.setFromType(ThisType->castAs<PointerType>()->getPointeeType());
User.After.setAllToTypes(ToType);
return Result;
}
case OR_No_Viable_Function:
return OR_No_Viable_Function;
case OR_Ambiguous:
return OR_Ambiguous;
}
llvm_unreachable("Invalid OverloadResult!");
}
/// Determines whether there is a user-defined conversion sequence
/// (C++ [over.ics.user]) that converts expression From to the type
/// ToType. If such a conversion exists, User will contain the
/// user-defined conversion sequence that performs such a conversion
/// and this routine will return true. Otherwise, this routine returns
/// false and User is unspecified.
///
/// \param AllowExplicit true if the conversion should consider C++0x
/// "explicit" conversion functions as well as non-explicit conversion
/// functions (C++0x [class.conv.fct]p2).
///
/// \param AllowObjCConversionOnExplicit true if the conversion should
/// allow an extra Objective-C pointer conversion on uses of explicit
/// constructors. Requires \c AllowExplicit to also be set.
static OverloadingResult
IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
UserDefinedConversionSequence &User,
OverloadCandidateSet &CandidateSet,
AllowedExplicit AllowExplicit,
bool AllowObjCConversionOnExplicit) {
assert(AllowExplicit != AllowedExplicit::None ||
!AllowObjCConversionOnExplicit);
CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
// Whether we will only visit constructors.
bool ConstructorsOnly = false;
// If the type we are conversion to is a class type, enumerate its
// constructors.
if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) {
// C++ [over.match.ctor]p1:
// When objects of class type are direct-initialized (8.5), or
// copy-initialized from an expression of the same or a
// derived class type (8.5), overload resolution selects the
// constructor. [...] For copy-initialization, the candidate
// functions are all the converting constructors (12.3.1) of
// that class. The argument list is the expression-list within
// the parentheses of the initializer.
if (S.Context.hasSameUnqualifiedType(ToType, From->getType()) ||
(From->getType()->getAs<RecordType>() &&
S.IsDerivedFrom(From->getBeginLoc(), From->getType(), ToType)))
ConstructorsOnly = true;
if (!S.isCompleteType(From->getExprLoc(), ToType)) {
// We're not going to find any constructors.
} else if (CXXRecordDecl *ToRecordDecl
= dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) {
Expr **Args = &From;
unsigned NumArgs = 1;
bool ListInitializing = false;
if (InitListExpr *InitList = dyn_cast<InitListExpr>(From)) {
// But first, see if there is an init-list-constructor that will work.
OverloadingResult Result = IsInitializerListConstructorConversion(
S, From, ToType, ToRecordDecl, User, CandidateSet,
AllowExplicit == AllowedExplicit::All);
if (Result != OR_No_Viable_Function)
return Result;
// Never mind.
CandidateSet.clear(
OverloadCandidateSet::CSK_InitByUserDefinedConversion);
// If we're list-initializing, we pass the individual elements as
// arguments, not the entire list.
Args = InitList->getInits();
NumArgs = InitList->getNumInits();
ListInitializing = true;
}
for (auto *D : S.LookupConstructors(ToRecordDecl)) {
auto Info = getConstructorInfo(D);
if (!Info)
continue;
bool Usable = !Info.Constructor->isInvalidDecl();
if (!ListInitializing)
Usable = Usable && Info.Constructor->isConvertingConstructor(
/*AllowExplicit*/ true);
if (Usable) {
bool SuppressUserConversions = !ConstructorsOnly;
// C++20 [over.best.ics.general]/4.5:
// if the target is the first parameter of a constructor [of class
// X] and the constructor [...] is a candidate by [...] the second
// phase of [over.match.list] when the initializer list has exactly
// one element that is itself an initializer list, [...] and the
// conversion is to X or reference to cv X, user-defined conversion
// sequences are not cnosidered.
if (SuppressUserConversions && ListInitializing) {
SuppressUserConversions =
NumArgs == 1 && isa<InitListExpr>(Args[0]) &&
isFirstArgumentCompatibleWithType(S.Context, Info.Constructor,
ToType);
}
if (Info.ConstructorTmpl)
S.AddTemplateOverloadCandidate(
Info.ConstructorTmpl, Info.FoundDecl,
/*ExplicitArgs*/ nullptr, llvm::makeArrayRef(Args, NumArgs),
CandidateSet, SuppressUserConversions,
/*PartialOverloading*/ false,
AllowExplicit == AllowedExplicit::All);
else
// Allow one user-defined conversion when user specifies a
// From->ToType conversion via an static cast (c-style, etc).
S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl,
llvm::makeArrayRef(Args, NumArgs),
CandidateSet, SuppressUserConversions,
/*PartialOverloading*/ false,
AllowExplicit == AllowedExplicit::All);
}
}
}
}
// Enumerate conversion functions, if we're allowed to.
if (ConstructorsOnly || isa<InitListExpr>(From)) {
} else if (!S.isCompleteType(From->getBeginLoc(), From->getType())) {
// No conversion functions from incomplete types.
} else if (const RecordType *FromRecordType =
From->getType()->getAs<RecordType>()) {
if (CXXRecordDecl *FromRecordDecl
= dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) {
// Add all of the conversion functions as candidates.
const auto &Conversions = FromRecordDecl->getVisibleConversionFunctions();
for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
DeclAccessPair FoundDecl = I.getPair();
NamedDecl *D = FoundDecl.getDecl();
CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
if (isa<UsingShadowDecl>(D))
D = cast<UsingShadowDecl>(D)->getTargetDecl();
CXXConversionDecl *Conv;
FunctionTemplateDecl *ConvTemplate;
if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D)))
Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
else
Conv = cast<CXXConversionDecl>(D);
if (ConvTemplate)
S.AddTemplateConversionCandidate(
ConvTemplate, FoundDecl, ActingContext, From, ToType,
CandidateSet, AllowObjCConversionOnExplicit,
AllowExplicit != AllowedExplicit::None);
else
S.AddConversionCandidate(Conv, FoundDecl, ActingContext, From, ToType,
CandidateSet, AllowObjCConversionOnExplicit,
AllowExplicit != AllowedExplicit::None);
}
}
}
bool HadMultipleCandidates = (CandidateSet.size() > 1);
OverloadCandidateSet::iterator Best;
switch (auto Result =
CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
case OR_Success:
case OR_Deleted:
// Record the standard conversion we used and the conversion function.
if (CXXConstructorDecl *Constructor
= dyn_cast<CXXConstructorDecl>(Best->Function)) {
// C++ [over.ics.user]p1:
// If the user-defined conversion is specified by a
// constructor (12.3.1), the initial standard conversion
// sequence converts the source type to the type required by
// the argument of the constructor.
//
QualType ThisType = Constructor->getThisType();
if (isa<InitListExpr>(From)) {
// Initializer lists don't have conversions as such.
User.Before.setAsIdentityConversion();
} else {
if (Best->Conversions[0].isEllipsis())
User.EllipsisConversion = true;
else {
User.Before = Best->Conversions[0].Standard;
User.EllipsisConversion = false;
}
}
User.HadMultipleCandidates = HadMultipleCandidates;
User.ConversionFunction = Constructor;
User.FoundConversionFunction = Best->FoundDecl;
User.After.setAsIdentityConversion();
User.After.setFromType(ThisType->castAs<PointerType>()->getPointeeType());
User.After.setAllToTypes(ToType);
return Result;
}
if (CXXConversionDecl *Conversion
= dyn_cast<CXXConversionDecl>(Best->Function)) {
// C++ [over.ics.user]p1:
//
// [...] If the user-defined conversion is specified by a
// conversion function (12.3.2), the initial standard
// conversion sequence converts the source type to the
// implicit object parameter of the conversion function.
User.Before = Best->Conversions[0].Standard;
User.HadMultipleCandidates = HadMultipleCandidates;
User.ConversionFunction = Conversion;
User.FoundConversionFunction = Best->FoundDecl;
User.EllipsisConversion = false;
// C++ [over.ics.user]p2:
// The second standard conversion sequence converts the
// result of the user-defined conversion to the target type
// for the sequence. Since an implicit conversion sequence
// is an initialization, the special rules for
// initialization by user-defined conversion apply when
// selecting the best user-defined conversion for a
// user-defined conversion sequence (see 13.3.3 and
// 13.3.3.1).
User.After = Best->FinalConversion;
return Result;
}
llvm_unreachable("Not a constructor or conversion function?");
case OR_No_Viable_Function:
return OR_No_Viable_Function;
case OR_Ambiguous:
return OR_Ambiguous;
}
llvm_unreachable("Invalid OverloadResult!");
}
bool
Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) {
ImplicitConversionSequence ICS;
OverloadCandidateSet CandidateSet(From->getExprLoc(),
OverloadCandidateSet::CSK_Normal);
OverloadingResult OvResult =
IsUserDefinedConversion(*this, From, ToType, ICS.UserDefined,
CandidateSet, AllowedExplicit::None, false);
if (!(OvResult == OR_Ambiguous ||
(OvResult == OR_No_Viable_Function && !CandidateSet.empty())))
return false;
auto Cands = CandidateSet.CompleteCandidates(
*this,
OvResult == OR_Ambiguous ? OCD_AmbiguousCandidates : OCD_AllCandidates,
From);
if (OvResult == OR_Ambiguous)
Diag(From->getBeginLoc(), diag::err_typecheck_ambiguous_condition)
<< From->getType() << ToType << From->getSourceRange();
else { // OR_No_Viable_Function && !CandidateSet.empty()
if (!RequireCompleteType(From->getBeginLoc(), ToType,
diag::err_typecheck_nonviable_condition_incomplete,
From->getType(), From->getSourceRange()))
Diag(From->getBeginLoc(), diag::err_typecheck_nonviable_condition)
<< false << From->getType() << From->getSourceRange() << ToType;
}
CandidateSet.NoteCandidates(
*this, From, Cands);
return true;
}
// Helper for compareConversionFunctions that gets the FunctionType that the
// conversion-operator return value 'points' to, or nullptr.
static const FunctionType *
getConversionOpReturnTyAsFunction(CXXConversionDecl *Conv) {
const FunctionType *ConvFuncTy = Conv->getType()->castAs<FunctionType>();
const PointerType *RetPtrTy =
ConvFuncTy->getReturnType()->getAs<PointerType>();
if (!RetPtrTy)
return nullptr;
return RetPtrTy->getPointeeType()->getAs<FunctionType>();
}
/// Compare the user-defined conversion functions or constructors
/// of two user-defined conversion sequences to determine whether any ordering
/// is possible.
static ImplicitConversionSequence::CompareKind
compareConversionFunctions(Sema &S, FunctionDecl *Function1,
FunctionDecl *Function2) {
CXXConversionDecl *Conv1 = dyn_cast_or_null<CXXConversionDecl>(Function1);
CXXConversionDecl *Conv2 = dyn_cast_or_null<CXXConversionDecl>(Function2);
if (!Conv1 || !Conv2)
return ImplicitConversionSequence::Indistinguishable;
if (!Conv1->getParent()->isLambda() || !Conv2->getParent()->isLambda())
return ImplicitConversionSequence::Indistinguishable;
// Objective-C++:
// If both conversion functions are implicitly-declared conversions from
// a lambda closure type to a function pointer and a block pointer,
// respectively, always prefer the conversion to a function pointer,
// because the function pointer is more lightweight and is more likely
// to keep code working.
if (S.getLangOpts().ObjC && S.getLangOpts().CPlusPlus11) {
bool Block1 = Conv1->getConversionType()->isBlockPointerType();
bool Block2 = Conv2->getConversionType()->isBlockPointerType();
if (Block1 != Block2)
return Block1 ? ImplicitConversionSequence::Worse
: ImplicitConversionSequence::Better;
}
// In order to support multiple calling conventions for the lambda conversion
// operator (such as when the free and member function calling convention is
// different), prefer the 'free' mechanism, followed by the calling-convention
// of operator(). The latter is in place to support the MSVC-like solution of
// defining ALL of the possible conversions in regards to calling-convention.
const FunctionType *Conv1FuncRet = getConversionOpReturnTyAsFunction(Conv1);
const FunctionType *Conv2FuncRet = getConversionOpReturnTyAsFunction(Conv2);
if (Conv1FuncRet && Conv2FuncRet &&
Conv1FuncRet->getCallConv() != Conv2FuncRet->getCallConv()) {
CallingConv Conv1CC = Conv1FuncRet->getCallConv();
CallingConv Conv2CC = Conv2FuncRet->getCallConv();
CXXMethodDecl *CallOp = Conv2->getParent()->getLambdaCallOperator();
const FunctionProtoType *CallOpProto =
CallOp->getType()->getAs<FunctionProtoType>();
CallingConv CallOpCC =
CallOp->getType()->castAs<FunctionType>()->getCallConv();
CallingConv DefaultFree = S.Context.getDefaultCallingConvention(
CallOpProto->isVariadic(), /*IsCXXMethod=*/false);
CallingConv DefaultMember = S.Context.getDefaultCallingConvention(
CallOpProto->isVariadic(), /*IsCXXMethod=*/true);
CallingConv PrefOrder[] = {DefaultFree, DefaultMember, CallOpCC};
for (CallingConv CC : PrefOrder) {
if (Conv1CC == CC)
return ImplicitConversionSequence::Better;
if (Conv2CC == CC)
return ImplicitConversionSequence::Worse;
}
}
return ImplicitConversionSequence::Indistinguishable;
}
static bool hasDeprecatedStringLiteralToCharPtrConversion(
const ImplicitConversionSequence &ICS) {
return (ICS.isStandard() && ICS.Standard.DeprecatedStringLiteralToCharPtr) ||
(ICS.isUserDefined() &&
ICS.UserDefined.Before.DeprecatedStringLiteralToCharPtr);
}
/// CompareImplicitConversionSequences - Compare two implicit
/// conversion sequences to determine whether one is better than the
/// other or if they are indistinguishable (C++ 13.3.3.2).
static ImplicitConversionSequence::CompareKind
CompareImplicitConversionSequences(Sema &S, SourceLocation Loc,
const ImplicitConversionSequence& ICS1,
const ImplicitConversionSequence& ICS2)
{
// (C++ 13.3.3.2p2): When comparing the basic forms of implicit
// conversion sequences (as defined in 13.3.3.1)
// -- a standard conversion sequence (13.3.3.1.1) is a better
// conversion sequence than a user-defined conversion sequence or
// an ellipsis conversion sequence, and
// -- a user-defined conversion sequence (13.3.3.1.2) is a better
// conversion sequence than an ellipsis conversion sequence
// (13.3.3.1.3).
//
// C++0x [over.best.ics]p10:
// For the purpose of ranking implicit conversion sequences as
// described in 13.3.3.2, the ambiguous conversion sequence is
// treated as a user-defined sequence that is indistinguishable
// from any other user-defined conversion sequence.
// String literal to 'char *' conversion has been deprecated in C++03. It has
// been removed from C++11. We still accept this conversion, if it happens at
// the best viable function. Otherwise, this conversion is considered worse
// than ellipsis conversion. Consider this as an extension; this is not in the
// standard. For example:
//
// int &f(...); // #1
// void f(char*); // #2
// void g() { int &r = f("foo"); }
//
// In C++03, we pick #2 as the best viable function.
// In C++11, we pick #1 as the best viable function, because ellipsis
// conversion is better than string-literal to char* conversion (since there
// is no such conversion in C++11). If there was no #1 at all or #1 couldn't
// convert arguments, #2 would be the best viable function in C++11.
// If the best viable function has this conversion, a warning will be issued
// in C++03, or an ExtWarn (+SFINAE failure) will be issued in C++11.
if (S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings &&
hasDeprecatedStringLiteralToCharPtrConversion(ICS1) !=
hasDeprecatedStringLiteralToCharPtrConversion(ICS2) &&
// Ill-formedness must not differ
ICS1.isBad() == ICS2.isBad())
return hasDeprecatedStringLiteralToCharPtrConversion(ICS1)
? ImplicitConversionSequence::Worse
: ImplicitConversionSequence::Better;
if (ICS1.getKindRank() < ICS2.getKindRank())
return ImplicitConversionSequence::Better;
if (ICS2.getKindRank() < ICS1.getKindRank())
return ImplicitConversionSequence::Worse;
// The following checks require both conversion sequences to be of
// the same kind.
if (ICS1.getKind() != ICS2.getKind())
return ImplicitConversionSequence::Indistinguishable;
ImplicitConversionSequence::CompareKind Result =
ImplicitConversionSequence::Indistinguishable;
// Two implicit conversion sequences of the same form are
// indistinguishable conversion sequences unless one of the
// following rules apply: (C++ 13.3.3.2p3):
// List-initialization sequence L1 is a better conversion sequence than
// list-initialization sequence L2 if:
// - L1 converts to std::initializer_list<X> for some X and L2 does not, or,
// if not that,
// — L1 and L2 convert to arrays of the same element type, and either the
// number of elements n_1 initialized by L1 is less than the number of
// elements n_2 initialized by L2, or (C++20) n_1 = n_2 and L2 converts to
// an array of unknown bound and L1 does not,
// even if one of the other rules in this paragraph would otherwise apply.
if (!ICS1.isBad()) {
bool StdInit1 = false, StdInit2 = false;
if (ICS1.hasInitializerListContainerType())
StdInit1 = S.isStdInitializerList(ICS1.getInitializerListContainerType(),
nullptr);
if (ICS2.hasInitializerListContainerType())
StdInit2 = S.isStdInitializerList(ICS2.getInitializerListContainerType(),
nullptr);
if (StdInit1 != StdInit2)
return StdInit1 ? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
if (ICS1.hasInitializerListContainerType() &&
ICS2.hasInitializerListContainerType())
if (auto *CAT1 = S.Context.getAsConstantArrayType(
ICS1.getInitializerListContainerType()))
if (auto *CAT2 = S.Context.getAsConstantArrayType(
ICS2.getInitializerListContainerType())) {
if (S.Context.hasSameUnqualifiedType(CAT1->getElementType(),
CAT2->getElementType())) {
// Both to arrays of the same element type
if (CAT1->getSize() != CAT2->getSize())
// Different sized, the smaller wins
return CAT1->getSize().ult(CAT2->getSize())
? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
if (ICS1.isInitializerListOfIncompleteArray() !=
ICS2.isInitializerListOfIncompleteArray())
// One is incomplete, it loses
return ICS2.isInitializerListOfIncompleteArray()
? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
}
}
}
if (ICS1.isStandard())
// Standard conversion sequence S1 is a better conversion sequence than
// standard conversion sequence S2 if [...]
Result = CompareStandardConversionSequences(S, Loc,
ICS1.Standard, ICS2.Standard);
else if (ICS1.isUserDefined()) {
// User-defined conversion sequence U1 is a better conversion
// sequence than another user-defined conversion sequence U2 if
// they contain the same user-defined conversion function or
// constructor and if the second standard conversion sequence of
// U1 is better than the second standard conversion sequence of
// U2 (C++ 13.3.3.2p3).
if (ICS1.UserDefined.ConversionFunction ==
ICS2.UserDefined.ConversionFunction)
Result = CompareStandardConversionSequences(S, Loc,
ICS1.UserDefined.After,
ICS2.UserDefined.After);
else
Result = compareConversionFunctions(S,
ICS1.UserDefined.ConversionFunction,
ICS2.UserDefined.ConversionFunction);
}
return Result;
}
// Per 13.3.3.2p3, compare the given standard conversion sequences to
// determine if one is a proper subset of the other.
static ImplicitConversionSequence::CompareKind
compareStandardConversionSubsets(ASTContext &Context,
const StandardConversionSequence& SCS1,
const StandardConversionSequence& SCS2) {
ImplicitConversionSequence::CompareKind Result
= ImplicitConversionSequence::Indistinguishable;
// the identity conversion sequence is considered to be a subsequence of
// any non-identity conversion sequence
if (SCS1.isIdentityConversion() && !SCS2.isIdentityConversion())
return ImplicitConversionSequence::Better;
else if (!SCS1.isIdentityConversion() && SCS2.isIdentityConversion())
return ImplicitConversionSequence::Worse;
if (SCS1.Second != SCS2.Second) {
if (SCS1.Second == ICK_Identity)
Result = ImplicitConversionSequence::Better;
else if (SCS2.Second == ICK_Identity)
Result = ImplicitConversionSequence::Worse;
else
return ImplicitConversionSequence::Indistinguishable;
} else if (!Context.hasSimilarType(SCS1.getToType(1), SCS2.getToType(1)))
return ImplicitConversionSequence::Indistinguishable;
if (SCS1.Third == SCS2.Third) {
return Context.hasSameType(SCS1.getToType(2), SCS2.getToType(2))? Result
: ImplicitConversionSequence::Indistinguishable;
}
if (SCS1.Third == ICK_Identity)
return Result == ImplicitConversionSequence::Worse
? ImplicitConversionSequence::Indistinguishable
: ImplicitConversionSequence::Better;
if (SCS2.Third == ICK_Identity)
return Result == ImplicitConversionSequence::Better
? ImplicitConversionSequence::Indistinguishable
: ImplicitConversionSequence::Worse;
return ImplicitConversionSequence::Indistinguishable;
}
/// Determine whether one of the given reference bindings is better
/// than the other based on what kind of bindings they are.
static bool
isBetterReferenceBindingKind(const StandardConversionSequence &SCS1,
const StandardConversionSequence &SCS2) {
// C++0x [over.ics.rank]p3b4:
// -- S1 and S2 are reference bindings (8.5.3) and neither refers to an
// implicit object parameter of a non-static member function declared
// without a ref-qualifier, and *either* S1 binds an rvalue reference
// to an rvalue and S2 binds an lvalue reference *or S1 binds an
// lvalue reference to a function lvalue and S2 binds an rvalue
// reference*.
//
// FIXME: Rvalue references. We're going rogue with the above edits,
// because the semantics in the current C++0x working paper (N3225 at the
// time of this writing) break the standard definition of std::forward
// and std::reference_wrapper when dealing with references to functions.
// Proposed wording changes submitted to CWG for consideration.
if (SCS1.BindsImplicitObjectArgumentWithoutRefQualifier ||
SCS2.BindsImplicitObjectArgumentWithoutRefQualifier)
return false;
return (!SCS1.IsLvalueReference && SCS1.BindsToRvalue &&
SCS2.IsLvalueReference) ||
(SCS1.IsLvalueReference && SCS1.BindsToFunctionLvalue &&
!SCS2.IsLvalueReference && SCS2.BindsToFunctionLvalue);
}
enum class FixedEnumPromotion {
None,
ToUnderlyingType,
ToPromotedUnderlyingType
};
/// Returns kind of fixed enum promotion the \a SCS uses.
static FixedEnumPromotion
getFixedEnumPromtion(Sema &S, const StandardConversionSequence &SCS) {
if (SCS.Second != ICK_Integral_Promotion)
return FixedEnumPromotion::None;
QualType FromType = SCS.getFromType();
if (!FromType->isEnumeralType())
return FixedEnumPromotion::None;
EnumDecl *Enum = FromType->castAs<EnumType>()->getDecl();
if (!Enum->isFixed())
return FixedEnumPromotion::None;
QualType UnderlyingType = Enum->getIntegerType();
if (S.Context.hasSameType(SCS.getToType(1), UnderlyingType))
return FixedEnumPromotion::ToUnderlyingType;
return FixedEnumPromotion::ToPromotedUnderlyingType;
}
/// CompareStandardConversionSequences - Compare two standard
/// conversion sequences to determine whether one is better than the
/// other or if they are indistinguishable (C++ 13.3.3.2p3).
static ImplicitConversionSequence::CompareKind
CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
const StandardConversionSequence& SCS1,
const StandardConversionSequence& SCS2)
{
// Standard conversion sequence S1 is a better conversion sequence
// than standard conversion sequence S2 if (C++ 13.3.3.2p3):
// -- S1 is a proper subsequence of S2 (comparing the conversion
// sequences in the canonical form defined by 13.3.3.1.1,
// excluding any Lvalue Transformation; the identity conversion
// sequence is considered to be a subsequence of any
// non-identity conversion sequence) or, if not that,
if (ImplicitConversionSequence::CompareKind CK
= compareStandardConversionSubsets(S.Context, SCS1, SCS2))
return CK;
// -- the rank of S1 is better than the rank of S2 (by the rules
// defined below), or, if not that,
ImplicitConversionRank Rank1 = SCS1.getRank();
ImplicitConversionRank Rank2 = SCS2.getRank();
if (Rank1 < Rank2)
return ImplicitConversionSequence::Better;
else if (Rank2 < Rank1)
return ImplicitConversionSequence::Worse;
// (C++ 13.3.3.2p4): Two conversion sequences with the same rank
// are indistinguishable unless one of the following rules
// applies:
// A conversion that is not a conversion of a pointer, or
// pointer to member, to bool is better than another conversion
// that is such a conversion.
if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool())
return SCS2.isPointerConversionToBool()
? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
// C++14 [over.ics.rank]p4b2:
// This is retroactively applied to C++11 by CWG 1601.
//
// A conversion that promotes an enumeration whose underlying type is fixed
// to its underlying type is better than one that promotes to the promoted
// underlying type, if the two are different.
FixedEnumPromotion FEP1 = getFixedEnumPromtion(S, SCS1);
FixedEnumPromotion FEP2 = getFixedEnumPromtion(S, SCS2);
if (FEP1 != FixedEnumPromotion::None && FEP2 != FixedEnumPromotion::None &&
FEP1 != FEP2)
return FEP1 == FixedEnumPromotion::ToUnderlyingType
? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
// C++ [over.ics.rank]p4b2:
//
// If class B is derived directly or indirectly from class A,
// conversion of B* to A* is better than conversion of B* to
// void*, and conversion of A* to void* is better than conversion
// of B* to void*.
bool SCS1ConvertsToVoid
= SCS1.isPointerConversionToVoidPointer(S.Context);
bool SCS2ConvertsToVoid
= SCS2.isPointerConversionToVoidPointer(S.Context);
if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) {
// Exactly one of the conversion sequences is a conversion to
// a void pointer; it's the worse conversion.
return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
} else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) {
// Neither conversion sequence converts to a void pointer; compare
// their derived-to-base conversions.
if (ImplicitConversionSequence::CompareKind DerivedCK
= CompareDerivedToBaseConversions(S, Loc, SCS1, SCS2))
return DerivedCK;
} else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid &&
!S.Context.hasSameType(SCS1.getFromType(), SCS2.getFromType())) {
// Both conversion sequences are conversions to void
// pointers. Compare the source types to determine if there's an
// inheritance relationship in their sources.
QualType FromType1 = SCS1.getFromType();
QualType FromType2 = SCS2.getFromType();
// Adjust the types we're converting from via the array-to-pointer
// conversion, if we need to.
if (SCS1.First == ICK_Array_To_Pointer)
FromType1 = S.Context.getArrayDecayedType(FromType1);
if (SCS2.First == ICK_Array_To_Pointer)
FromType2 = S.Context.getArrayDecayedType(FromType2);
QualType FromPointee1 = FromType1->getPointeeType().getUnqualifiedType();
QualType FromPointee2 = FromType2->getPointeeType().getUnqualifiedType();
if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
return ImplicitConversionSequence::Better;
else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
return ImplicitConversionSequence::Worse;
// Objective-C++: If one interface is more specific than the
// other, it is the better one.
const ObjCObjectPointerType* FromObjCPtr1
= FromType1->getAs<ObjCObjectPointerType>();
const ObjCObjectPointerType* FromObjCPtr2
= FromType2->getAs<ObjCObjectPointerType>();
if (FromObjCPtr1 && FromObjCPtr2) {
bool AssignLeft = S.Context.canAssignObjCInterfaces(FromObjCPtr1,
FromObjCPtr2);
bool AssignRight = S.Context.canAssignObjCInterfaces(FromObjCPtr2,
FromObjCPtr1);
if (AssignLeft != AssignRight) {
return AssignLeft? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
}
}
}
if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
// Check for a better reference binding based on the kind of bindings.
if (isBetterReferenceBindingKind(SCS1, SCS2))
return ImplicitConversionSequence::Better;
else if (isBetterReferenceBindingKind(SCS2, SCS1))
return ImplicitConversionSequence::Worse;
}
// Compare based on qualification conversions (C++ 13.3.3.2p3,
// bullet 3).
if (ImplicitConversionSequence::CompareKind QualCK
= CompareQualificationConversions(S, SCS1, SCS2))
return QualCK;
if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
// C++ [over.ics.rank]p3b4:
// -- S1 and S2 are reference bindings (8.5.3), and the types to
// which the references refer are the same type except for
// top-level cv-qualifiers, and the type to which the reference
// initialized by S2 refers is more cv-qualified than the type
// to which the reference initialized by S1 refers.
QualType T1 = SCS1.getToType(2);
QualType T2 = SCS2.getToType(2);
T1 = S.Context.getCanonicalType(T1);
T2 = S.Context.getCanonicalType(T2);
Qualifiers T1Quals, T2Quals;
QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);
if (UnqualT1 == UnqualT2) {
// Objective-C++ ARC: If the references refer to objects with different
// lifetimes, prefer bindings that don't change lifetime.
if (SCS1.ObjCLifetimeConversionBinding !=
SCS2.ObjCLifetimeConversionBinding) {
return SCS1.ObjCLifetimeConversionBinding
? ImplicitConversionSequence::Worse
: ImplicitConversionSequence::Better;
}
// If the type is an array type, promote the element qualifiers to the
// type for comparison.
if (isa<ArrayType>(T1) && T1Quals)
T1 = S.Context.getQualifiedType(UnqualT1, T1Quals);
if (isa<ArrayType>(T2) && T2Quals)
T2 = S.Context.getQualifiedType(UnqualT2, T2Quals);
if (T2.isMoreQualifiedThan(T1))
return ImplicitConversionSequence::Better;
if (T1.isMoreQualifiedThan(T2))
return ImplicitConversionSequence::Worse;
}
}
// In Microsoft mode (below 19.28), prefer an integral conversion to a
// floating-to-integral conversion if the integral conversion
// is between types of the same size.
// For example:
// void f(float);
// void f(int);
// int main {
// long a;
// f(a);
// }
// Here, MSVC will call f(int) instead of generating a compile error
// as clang will do in standard mode.
if (S.getLangOpts().MSVCCompat &&
!S.getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2019_8) &&
SCS1.Second == ICK_Integral_Conversion &&
SCS2.Second == ICK_Floating_Integral &&
S.Context.getTypeSize(SCS1.getFromType()) ==
S.Context.getTypeSize(SCS1.getToType(2)))
return ImplicitConversionSequence::Better;
// Prefer a compatible vector conversion over a lax vector conversion
// For example:
//
// typedef float __v4sf __attribute__((__vector_size__(16)));
// void f(vector float);
// void f(vector signed int);
// int main() {
// __v4sf a;
// f(a);
// }
// Here, we'd like to choose f(vector float) and not
// report an ambiguous call error
if (SCS1.Second == ICK_Vector_Conversion &&
SCS2.Second == ICK_Vector_Conversion) {
bool SCS1IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
SCS1.getFromType(), SCS1.getToType(2));
bool SCS2IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
SCS2.getFromType(), SCS2.getToType(2));
if (SCS1IsCompatibleVectorConversion != SCS2IsCompatibleVectorConversion)
return SCS1IsCompatibleVectorConversion
? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
}
if (SCS1.Second == ICK_SVE_Vector_Conversion &&
SCS2.Second == ICK_SVE_Vector_Conversion) {
bool SCS1IsCompatibleSVEVectorConversion =
S.Context.areCompatibleSveTypes(SCS1.getFromType(), SCS1.getToType(2));
bool SCS2IsCompatibleSVEVectorConversion =
S.Context.areCompatibleSveTypes(SCS2.getFromType(), SCS2.getToType(2));
if (SCS1IsCompatibleSVEVectorConversion !=
SCS2IsCompatibleSVEVectorConversion)
return SCS1IsCompatibleSVEVectorConversion
? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
}
return ImplicitConversionSequence::Indistinguishable;
}
/// CompareQualificationConversions - Compares two standard conversion
/// sequences to determine whether they can be ranked based on their
/// qualification conversions (C++ 13.3.3.2p3 bullet 3).
static ImplicitConversionSequence::CompareKind
CompareQualificationConversions(Sema &S,
const StandardConversionSequence& SCS1,
const StandardConversionSequence& SCS2) {
// C++ [over.ics.rank]p3:
// -- S1 and S2 differ only in their qualification conversion and
// yield similar types T1 and T2 (C++ 4.4), respectively, [...]
// [C++98]
// [...] and the cv-qualification signature of type T1 is a proper subset
// of the cv-qualification signature of type T2, and S1 is not the
// deprecated string literal array-to-pointer conversion (4.2).
// [C++2a]
// [...] where T1 can be converted to T2 by a qualification conversion.
if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second ||
SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification)
return ImplicitConversionSequence::Indistinguishable;
// FIXME: the example in the standard doesn't use a qualification
// conversion (!)
QualType T1 = SCS1.getToType(2);
QualType T2 = SCS2.getToType(2);
T1 = S.Context.getCanonicalType(T1);
T2 = S.Context.getCanonicalType(T2);
assert(!T1->isReferenceType() && !T2->isReferenceType());
Qualifiers T1Quals, T2Quals;
QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);
// If the types are the same, we won't learn anything by unwrapping
// them.
if (UnqualT1 == UnqualT2)
return ImplicitConversionSequence::Indistinguishable;
// Don't ever prefer a standard conversion sequence that uses the deprecated
// string literal array to pointer conversion.
bool CanPick1 = !SCS1.DeprecatedStringLiteralToCharPtr;
bool CanPick2 = !SCS2.DeprecatedStringLiteralToCharPtr;
// Objective-C++ ARC:
// Prefer qualification conversions not involving a change in lifetime
// to qualification conversions that do change lifetime.
if (SCS1.QualificationIncludesObjCLifetime &&
!SCS2.QualificationIncludesObjCLifetime)
CanPick1 = false;
if (SCS2.QualificationIncludesObjCLifetime &&
!SCS1.QualificationIncludesObjCLifetime)
CanPick2 = false;
bool ObjCLifetimeConversion;
if (CanPick1 &&
!S.IsQualificationConversion(T1, T2, false, ObjCLifetimeConversion))
CanPick1 = false;
// FIXME: In Objective-C ARC, we can have qualification conversions in both
// directions, so we can't short-cut this second check in general.
if (CanPick2 &&
!S.IsQualificationConversion(T2, T1, false, ObjCLifetimeConversion))
CanPick2 = false;
if (CanPick1 != CanPick2)
return CanPick1 ? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
return ImplicitConversionSequence::Indistinguishable;
}
/// CompareDerivedToBaseConversions - Compares two standard conversion
/// sequences to determine whether they can be ranked based on their
/// various kinds of derived-to-base conversions (C++
/// [over.ics.rank]p4b3). As part of these checks, we also look at
/// conversions between Objective-C interface types.
static ImplicitConversionSequence::CompareKind
CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc,
const StandardConversionSequence& SCS1,
const StandardConversionSequence& SCS2) {
QualType FromType1 = SCS1.getFromType();
QualType ToType1 = SCS1.getToType(1);
QualType FromType2 = SCS2.getFromType();
QualType ToType2 = SCS2.getToType(1);
// Adjust the types we're converting from via the array-to-pointer
// conversion, if we need to.
if (SCS1.First == ICK_Array_To_Pointer)
FromType1 = S.Context.getArrayDecayedType(FromType1);
if (SCS2.First == ICK_Array_To_Pointer)
FromType2 = S.Context.getArrayDecayedType(FromType2);
// Canonicalize all of the types.
FromType1 = S.Context.getCanonicalType(FromType1);
ToType1 = S.Context.getCanonicalType(ToType1);
FromType2 = S.Context.getCanonicalType(FromType2);
ToType2 = S.Context.getCanonicalType(ToType2);
// C++ [over.ics.rank]p4b3:
//
// If class B is derived directly or indirectly from class A and
// class C is derived directly or indirectly from B,
//
// Compare based on pointer conversions.
if (SCS1.Second == ICK_Pointer_Conversion &&
SCS2.Second == ICK_Pointer_Conversion &&
/*FIXME: Remove if Objective-C id conversions get their own rank*/
FromType1->isPointerType() && FromType2->isPointerType() &&
ToType1->isPointerType() && ToType2->isPointerType()) {
QualType FromPointee1 =
FromType1->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
QualType ToPointee1 =
ToType1->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
QualType FromPointee2 =
FromType2->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
QualType ToPointee2 =
ToType2->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
// -- conversion of C* to B* is better than conversion of C* to A*,
if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
return ImplicitConversionSequence::Better;
else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
return ImplicitConversionSequence::Worse;
}
// -- conversion of B* to A* is better than conversion of C* to A*,
if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) {
if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
return ImplicitConversionSequence::Better;
else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
return ImplicitConversionSequence::Worse;
}
} else if (SCS1.Second == ICK_Pointer_Conversion &&
SCS2.Second == ICK_Pointer_Conversion) {
const ObjCObjectPointerType *FromPtr1
= FromType1->getAs<ObjCObjectPointerType>();
const ObjCObjectPointerType *FromPtr2
= FromType2->getAs<ObjCObjectPointerType>();
const ObjCObjectPointerType *ToPtr1
= ToType1->getAs<ObjCObjectPointerType>();
const ObjCObjectPointerType *ToPtr2
= ToType2->getAs<ObjCObjectPointerType>();
if (FromPtr1 && FromPtr2 && ToPtr1 && ToPtr2) {
// Apply the same conversion ranking rules for Objective-C pointer types
// that we do for C++ pointers to class types. However, we employ the
// Objective-C pseudo-subtyping relationship used for assignment of
// Objective-C pointer types.
bool FromAssignLeft
= S.Context.canAssignObjCInterfaces(FromPtr1, FromPtr2);
bool FromAssignRight
= S.Context.canAssignObjCInterfaces(FromPtr2, FromPtr1);
bool ToAssignLeft
= S.Context.canAssignObjCInterfaces(ToPtr1, ToPtr2);
bool ToAssignRight
= S.Context.canAssignObjCInterfaces(ToPtr2, ToPtr1);
// A conversion to an a non-id object pointer type or qualified 'id'
// type is better than a conversion to 'id'.
if (ToPtr1->isObjCIdType() &&
(ToPtr2->isObjCQualifiedIdType() || ToPtr2->getInterfaceDecl()))
return ImplicitConversionSequence::Worse;
if (ToPtr2->isObjCIdType() &&
(ToPtr1->isObjCQualifiedIdType() || ToPtr1->getInterfaceDecl()))
return ImplicitConversionSequence::Better;
// A conversion to a non-id object pointer type is better than a
// conversion to a qualified 'id' type
if (ToPtr1->isObjCQualifiedIdType() && ToPtr2->getInterfaceDecl())
return ImplicitConversionSequence::Worse;
if (ToPtr2->isObjCQualifiedIdType() && ToPtr1->getInterfaceDecl())
return ImplicitConversionSequence::Better;
// A conversion to an a non-Class object pointer type or qualified 'Class'
// type is better than a conversion to 'Class'.
if (ToPtr1->isObjCClassType() &&
(ToPtr2->isObjCQualifiedClassType() || ToPtr2->getInterfaceDecl()))
return ImplicitConversionSequence::Worse;
if (ToPtr2->isObjCClassType() &&
(ToPtr1->isObjCQualifiedClassType() || ToPtr1->getInterfaceDecl()))
return ImplicitConversionSequence::Better;
// A conversion to a non-Class object pointer type is better than a
// conversion to a qualified 'Class' type.
if (ToPtr1->isObjCQualifiedClassType() && ToPtr2->getInterfaceDecl())
return ImplicitConversionSequence::Worse;
if (ToPtr2->isObjCQualifiedClassType() && ToPtr1->getInterfaceDecl())
return ImplicitConversionSequence::Better;
// -- "conversion of C* to B* is better than conversion of C* to A*,"
if (S.Context.hasSameType(FromType1, FromType2) &&
!FromPtr1->isObjCIdType() && !FromPtr1->isObjCClassType() &&
(ToAssignLeft != ToAssignRight)) {
if (FromPtr1->isSpecialized()) {
// "conversion of B<A> * to B * is better than conversion of B * to
// C *.
bool IsFirstSame =
FromPtr1->getInterfaceDecl() == ToPtr1->getInterfaceDecl();
bool IsSecondSame =
FromPtr1->getInterfaceDecl() == ToPtr2->getInterfaceDecl();
if (IsFirstSame) {
if (!IsSecondSame)
return ImplicitConversionSequence::Better;
} else if (IsSecondSame)
return ImplicitConversionSequence::Worse;
}
return ToAssignLeft? ImplicitConversionSequence::Worse
: ImplicitConversionSequence::Better;
}
// -- "conversion of B* to A* is better than conversion of C* to A*,"
if (S.Context.hasSameUnqualifiedType(ToType1, ToType2) &&
(FromAssignLeft != FromAssignRight))
return FromAssignLeft? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
}
}
// Ranking of member-pointer types.
if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member &&
FromType1->isMemberPointerType() && FromType2->isMemberPointerType() &&
ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) {
const auto *FromMemPointer1 = FromType1->castAs<MemberPointerType>();
const auto *ToMemPointer1 = ToType1->castAs<MemberPointerType>();
const auto *FromMemPointer2 = FromType2->castAs<MemberPointerType>();
const auto *ToMemPointer2 = ToType2->castAs<MemberPointerType>();
const Type *FromPointeeType1 = FromMemPointer1->getClass();
const Type *ToPointeeType1 = ToMemPointer1->getClass();
const Type *FromPointeeType2 = FromMemPointer2->getClass();
const Type *ToPointeeType2 = ToMemPointer2->getClass();
QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType();
QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType();
QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType();
QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType();
// conversion of A::* to B::* is better than conversion of A::* to C::*,
if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
return ImplicitConversionSequence::Worse;
else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
return ImplicitConversionSequence::Better;
}
// conversion of B::* to C::* is better than conversion of A::* to C::*
if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) {
if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
return ImplicitConversionSequence::Better;
else if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
return ImplicitConversionSequence::Worse;
}
}
if (SCS1.Second == ICK_Derived_To_Base) {
// -- conversion of C to B is better than conversion of C to A,
// -- binding of an expression of type C to a reference of type
// B& is better than binding an expression of type C to a
// reference of type A&,
if (S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
!S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
if (S.IsDerivedFrom(Loc, ToType1, ToType2))
return ImplicitConversionSequence::Better;
else if (S.IsDerivedFrom(Loc, ToType2, ToType1))
return ImplicitConversionSequence::Worse;
}
// -- conversion of B to A is better than conversion of C to A.
// -- binding of an expression of type B to a reference of type
// A& is better than binding an expression of type C to a
// reference of type A&,
if (!S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
if (S.IsDerivedFrom(Loc, FromType2, FromType1))
return ImplicitConversionSequence::Better;
else if (S.IsDerivedFrom(Loc, FromType1, FromType2))
return ImplicitConversionSequence::Worse;
}
}
return ImplicitConversionSequence::Indistinguishable;
}
/// Determine whether the given type is valid, e.g., it is not an invalid
/// C++ class.
static bool isTypeValid(QualType T) {
if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
return !Record->isInvalidDecl();
return true;
}
static QualType withoutUnaligned(ASTContext &Ctx, QualType T) {
if (!T.getQualifiers().hasUnaligned())
return T;
Qualifiers Q;
T = Ctx.getUnqualifiedArrayType(T, Q);
Q.removeUnaligned();
return Ctx.getQualifiedType(T, Q);
}
/// CompareReferenceRelationship - Compare the two types T1 and T2 to
/// determine whether they are reference-compatible,
/// reference-related, or incompatible, for use in C++ initialization by
/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference
/// type, and the first type (T1) is the pointee type of the reference
/// type being initialized.
Sema::ReferenceCompareResult
Sema::CompareReferenceRelationship(SourceLocation Loc,
QualType OrigT1, QualType OrigT2,
ReferenceConversions *ConvOut) {
assert(!OrigT1->isReferenceType() &&
"T1 must be the pointee type of the reference type");
assert(!OrigT2->isReferenceType() && "T2 cannot be a reference type");
QualType T1 = Context.getCanonicalType(OrigT1);
QualType T2 = Context.getCanonicalType(OrigT2);
Qualifiers T1Quals, T2Quals;
QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals);
QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals);
ReferenceConversions ConvTmp;
ReferenceConversions &Conv = ConvOut ? *ConvOut : ConvTmp;
Conv = ReferenceConversions();
// C++2a [dcl.init.ref]p4:
// Given types "cv1 T1" and "cv2 T2," "cv1 T1" is
// reference-related to "cv2 T2" if T1 is similar to T2, or
// T1 is a base class of T2.
// "cv1 T1" is reference-compatible with "cv2 T2" if
// a prvalue of type "pointer to cv2 T2" can be converted to the type
// "pointer to cv1 T1" via a standard conversion sequence.
// Check for standard conversions we can apply to pointers: derived-to-base
// conversions, ObjC pointer conversions, and function pointer conversions.
// (Qualification conversions are checked last.)
QualType ConvertedT2;
if (UnqualT1 == UnqualT2) {
// Nothing to do.
} else if (isCompleteType(Loc, OrigT2) &&
isTypeValid(UnqualT1) && isTypeValid(UnqualT2) &&
IsDerivedFrom(Loc, UnqualT2, UnqualT1))
Conv |= ReferenceConversions::DerivedToBase;
else if (UnqualT1->isObjCObjectOrInterfaceType() &&
UnqualT2->isObjCObjectOrInterfaceType() &&
Context.canBindObjCObjectType(UnqualT1, UnqualT2))
Conv |= ReferenceConversions::ObjC;
else if (UnqualT2->isFunctionType() &&
IsFunctionConversion(UnqualT2, UnqualT1, ConvertedT2)) {
Conv |= ReferenceConversions::Function;
// No need to check qualifiers; function types don't have them.
return Ref_Compatible;
}
bool ConvertedReferent = Conv != 0;
// We can have a qualification conversion. Compute whether the types are
// similar at the same time.
bool PreviousToQualsIncludeConst = true;
bool TopLevel = true;
do {
if (T1 == T2)
break;
// We will need a qualification conversion.
Conv |= ReferenceConversions::Qualification;
// Track whether we performed a qualification conversion anywhere other
// than the top level. This matters for ranking reference bindings in
// overload resolution.
if (!TopLevel)
Conv |= ReferenceConversions::NestedQualification;
// MS compiler ignores __unaligned qualifier for references; do the same.
T1 = withoutUnaligned(Context, T1);
T2 = withoutUnaligned(Context, T2);
// If we find a qualifier mismatch, the types are not reference-compatible,
// but are still be reference-related if they're similar.
bool ObjCLifetimeConversion = false;
if (!isQualificationConversionStep(T2, T1, /*CStyle=*/false, TopLevel,
PreviousToQualsIncludeConst,
ObjCLifetimeConversion))
return (ConvertedReferent || Context.hasSimilarType(T1, T2))
? Ref_Related
: Ref_Incompatible;
// FIXME: Should we track this for any level other than the first?
if (ObjCLifetimeConversion)
Conv |= ReferenceConversions::ObjCLifetime;
TopLevel = false;
} while (Context.UnwrapSimilarTypes(T1, T2));
// At this point, if the types are reference-related, we must either have the
// same inner type (ignoring qualifiers), or must have already worked out how
// to convert the referent.
return (ConvertedReferent || Context.hasSameUnqualifiedType(T1, T2))
? Ref_Compatible
: Ref_Incompatible;
}
/// Look for a user-defined conversion to a value reference-compatible
/// with DeclType. Return true if something definite is found.
static bool
FindConversionForRefInit(Sema &S, ImplicitConversionSequence &ICS,
QualType DeclType, SourceLocation DeclLoc,
Expr *Init, QualType T2, bool AllowRvalues,
bool AllowExplicit) {
assert(T2->isRecordType() && "Can only find conversions of record types.");
auto *T2RecordDecl = cast<CXXRecordDecl>(T2->castAs<RecordType>()->getDecl());
OverloadCandidateSet CandidateSet(
DeclLoc, OverloadCandidateSet::CSK_InitByUserDefinedConversion);
const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions();
for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
NamedDecl *D = *I;
CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
if (isa<UsingShadowDecl>(D))
D = cast<UsingShadowDecl>(D)->getTargetDecl();
FunctionTemplateDecl *ConvTemplate
= dyn_cast<FunctionTemplateDecl>(D);
CXXConversionDecl *Conv;
if (ConvTemplate)
Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
else
Conv = cast<CXXConversionDecl>(D);
if (AllowRvalues) {
// If we are initializing an rvalue reference, don't permit conversion
// functions that return lvalues.
if (!ConvTemplate && DeclType->isRValueReferenceType()) {
const ReferenceType *RefType
= Conv->getConversionType()->getAs<LValueReferenceType>();
if (RefType && !RefType->getPointeeType()->isFunctionType())
continue;
}
if (!ConvTemplate &&
S.CompareReferenceRelationship(
DeclLoc,
Conv->getConversionType()
.getNonReferenceType()
.getUnqualifiedType(),
DeclType.getNonReferenceType().getUnqualifiedType()) ==
Sema::Ref_Incompatible)
continue;
} else {
// If the conversion function doesn't return a reference type,
// it can't be considered for this conversion. An rvalue reference
// is only acceptable if its referencee is a function type.
const ReferenceType *RefType =
Conv->getConversionType()->getAs<ReferenceType>();
if (!RefType ||
(!RefType->isLValueReferenceType() &&
!RefType->getPointeeType()->isFunctionType()))
continue;
}
if (ConvTemplate)
S.AddTemplateConversionCandidate(
ConvTemplate, I.getPair(), ActingDC, Init, DeclType, CandidateSet,
/*AllowObjCConversionOnExplicit=*/false, AllowExplicit);
else
S.AddConversionCandidate(
Conv, I.getPair(), ActingDC, Init, DeclType, CandidateSet,
/*AllowObjCConversionOnExplicit=*/false, AllowExplicit);
}
bool HadMultipleCandidates = (CandidateSet.size() > 1);
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(S, DeclLoc, Best)) {
case OR_Success:
// C++ [over.ics.ref]p1:
//
// [...] If the parameter binds directly to the result of
// applying a conversion function to the argument
// expression, the implicit conversion sequence is a
// user-defined conversion sequence (13.3.3.1.2), with the
// second standard conversion sequence either an identity
// conversion or, if the conversion function returns an
// entity of a type that is a derived class of the parameter
// type, a derived-to-base Conversion.
if (!Best->FinalConversion.DirectBinding)
return false;
ICS.setUserDefined();
ICS.UserDefined.Before = Best->Conversions[0].Standard;
ICS.UserDefined.After = Best->FinalConversion;
ICS.UserDefined.HadMultipleCandidates = HadMultipleCandidates;
ICS.UserDefined.ConversionFunction = Best->Function;
ICS.UserDefined.FoundConversionFunction = Best->FoundDecl;
ICS.UserDefined.EllipsisConversion = false;
assert(ICS.UserDefined.After.ReferenceBinding &&
ICS.UserDefined.After.DirectBinding &&
"Expected a direct reference binding!");
return true;
case OR_Ambiguous:
ICS.setAmbiguous();
for (OverloadCandidateSet::iterator Cand = CandidateSet.begin();
Cand != CandidateSet.end(); ++Cand)
if (Cand->Best)
ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function);
return true;
case OR_No_Viable_Function:
case OR_Deleted:
// There was no suitable conversion, or we found a deleted
// conversion; continue with other checks.
return false;
}
llvm_unreachable("Invalid OverloadResult!");
}
/// Compute an implicit conversion sequence for reference
/// initialization.
static ImplicitConversionSequence
TryReferenceInit(Sema &S, Expr *Init, QualType DeclType,
SourceLocation DeclLoc,
bool SuppressUserConversions,
bool AllowExplicit) {
assert(DeclType->isReferenceType() && "Reference init needs a reference");
// Most paths end in a failed conversion.
ImplicitConversionSequence ICS;
ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
QualType T1 = DeclType->castAs<ReferenceType>()->getPointeeType();
QualType T2 = Init->getType();
// If the initializer is the address of an overloaded function, try
// to resolve the overloaded function. If all goes well, T2 is the
// type of the resulting function.
if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
DeclAccessPair Found;
if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(Init, DeclType,
false, Found))
T2 = Fn->getType();
}
// Compute some basic properties of the types and the initializer.
bool isRValRef = DeclType->isRValueReferenceType();
Expr::Classification InitCategory = Init->Classify(S.Context);
Sema::ReferenceConversions RefConv;
Sema::ReferenceCompareResult RefRelationship =
S.CompareReferenceRelationship(DeclLoc, T1, T2, &RefConv);
auto SetAsReferenceBinding = [&](bool BindsDirectly) {
ICS.setStandard();
ICS.Standard.First = ICK_Identity;
// FIXME: A reference binding can be a function conversion too. We should
// consider that when ordering reference-to-function bindings.
ICS.Standard.Second = (RefConv & Sema::ReferenceConversions::DerivedToBase)
? ICK_Derived_To_Base
: (RefConv & Sema::ReferenceConversions::ObjC)
? ICK_Compatible_Conversion
: ICK_Identity;
// FIXME: As a speculative fix to a defect introduced by CWG2352, we rank
// a reference binding that performs a non-top-level qualification
// conversion as a qualification conversion, not as an identity conversion.
ICS.Standard.Third = (RefConv &
Sema::ReferenceConversions::NestedQualification)
? ICK_Qualification
: ICK_Identity;
ICS.Standard.setFromType(T2);
ICS.Standard.setToType(0, T2);
ICS.Standard.setToType(1, T1);
ICS.Standard.setToType(2, T1);
ICS.Standard.ReferenceBinding = true;
ICS.Standard.DirectBinding = BindsDirectly;
ICS.Standard.IsLvalueReference = !isRValRef;
ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType();
ICS.Standard.BindsToRvalue = InitCategory.isRValue();
ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
ICS.Standard.ObjCLifetimeConversionBinding =
(RefConv & Sema::ReferenceConversions::ObjCLifetime) != 0;
ICS.Standard.CopyConstructor = nullptr;
ICS.Standard.DeprecatedStringLiteralToCharPtr = false;
};
// C++0x [dcl.init.ref]p5:
// A reference to type "cv1 T1" is initialized by an expression
// of type "cv2 T2" as follows:
// -- If reference is an lvalue reference and the initializer expression
if (!isRValRef) {
// -- is an lvalue (but is not a bit-field), and "cv1 T1" is
// reference-compatible with "cv2 T2," or
//
// Per C++ [over.ics.ref]p4, we don't check the bit-field property here.
if (InitCategory.isLValue() && RefRelationship == Sema::Ref_Compatible) {
// C++ [over.ics.ref]p1:
// When a parameter of reference type binds directly (8.5.3)
// to an argument expression, the implicit conversion sequence
// is the identity conversion, unless the argument expression
// has a type that is a derived class of the parameter type,
// in which case the implicit conversion sequence is a
// derived-to-base Conversion (13.3.3.1).
SetAsReferenceBinding(/*BindsDirectly=*/true);
// Nothing more to do: the inaccessibility/ambiguity check for
// derived-to-base conversions is suppressed when we're
// computing the implicit conversion sequence (C++
// [over.best.ics]p2).
return ICS;
}
// -- has a class type (i.e., T2 is a class type), where T1 is
// not reference-related to T2, and can be implicitly
// converted to an lvalue of type "cv3 T3," where "cv1 T1"
// is reference-compatible with "cv3 T3" 92) (this
// conversion is selected by enumerating the applicable
// conversion functions (13.3.1.6) and choosing the best
// one through overload resolution (13.3)),
if (!SuppressUserConversions && T2->isRecordType() &&
S.isCompleteType(DeclLoc, T2) &&
RefRelationship == Sema::Ref_Incompatible) {
if (FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
Init, T2, /*AllowRvalues=*/false,
AllowExplicit))
return ICS;
}
}
// -- Otherwise, the reference shall be an lvalue reference to a
// non-volatile const type (i.e., cv1 shall be const), or the reference
// shall be an rvalue reference.
if (!isRValRef && (!T1.isConstQualified() || T1.isVolatileQualified())) {
if (InitCategory.isRValue() && RefRelationship != Sema::Ref_Incompatible)
ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, Init, DeclType);
return ICS;
}
// -- If the initializer expression
//
// -- is an xvalue, class prvalue, array prvalue or function
// lvalue and "cv1 T1" is reference-compatible with "cv2 T2", or
if (RefRelationship == Sema::Ref_Compatible &&
(InitCategory.isXValue() ||
(InitCategory.isPRValue() &&
(T2->isRecordType() || T2->isArrayType())) ||
(InitCategory.isLValue() && T2->isFunctionType()))) {
// In C++11, this is always a direct binding. In C++98/03, it's a direct
// binding unless we're binding to a class prvalue.
// Note: Although xvalues wouldn't normally show up in C++98/03 code, we
// allow the use of rvalue references in C++98/03 for the benefit of
// standard library implementors; therefore, we need the xvalue check here.
SetAsReferenceBinding(/*BindsDirectly=*/S.getLangOpts().CPlusPlus11 ||
!(InitCategory.isPRValue() || T2->isRecordType()));
return ICS;
}
// -- has a class type (i.e., T2 is a class type), where T1 is not
// reference-related to T2, and can be implicitly converted to
// an xvalue, class prvalue, or function lvalue of type
// "cv3 T3", where "cv1 T1" is reference-compatible with
// "cv3 T3",
//
// then the reference is bound to the value of the initializer
// expression in the first case and to the result of the conversion
// in the second case (or, in either case, to an appropriate base
// class subobject).
if (!SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
T2->isRecordType() && S.isCompleteType(DeclLoc, T2) &&
FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
Init, T2, /*AllowRvalues=*/true,
AllowExplicit)) {
// In the second case, if the reference is an rvalue reference
// and the second standard conversion sequence of the
// user-defined conversion sequence includes an lvalue-to-rvalue
// conversion, the program is ill-formed.
if (ICS.isUserDefined() && isRValRef &&
ICS.UserDefined.After.First == ICK_Lvalue_To_Rvalue)
ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
return ICS;
}
// A temporary of function type cannot be created; don't even try.
if (T1->isFunctionType())
return ICS;
// -- Otherwise, a temporary of type "cv1 T1" is created and
// initialized from the initializer expression using the
// rules for a non-reference copy initialization (8.5). The
// reference is then bound to the temporary. If T1 is
// reference-related to T2, cv1 must be the same
// cv-qualification as, or greater cv-qualification than,
// cv2; otherwise, the program is ill-formed.
if (RefRelationship == Sema::Ref_Related) {
// If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then
// we would be reference-compatible or reference-compatible with
// added qualification. But that wasn't the case, so the reference
// initialization fails.
//
// Note that we only want to check address spaces and cvr-qualifiers here.
// ObjC GC, lifetime and unaligned qualifiers aren't important.
Qualifiers T1Quals = T1.getQualifiers();
Qualifiers T2Quals = T2.getQualifiers();
T1Quals.removeObjCGCAttr();
T1Quals.removeObjCLifetime();
T2Quals.removeObjCGCAttr();
T2Quals.removeObjCLifetime();
// MS compiler ignores __unaligned qualifier for references; do the same.
T1Quals.removeUnaligned();
T2Quals.removeUnaligned();
if (!T1Quals.compatiblyIncludes(T2Quals))
return ICS;
}
// If at least one of the types is a class type, the types are not
// related, and we aren't allowed any user conversions, the
// reference binding fails. This case is important for breaking
// recursion, since TryImplicitConversion below will attempt to
// create a temporary through the use of a copy constructor.
if (SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
(T1->isRecordType() || T2->isRecordType()))
return ICS;
// If T1 is reference-related to T2 and the reference is an rvalue
// reference, the initializer expression shall not be an lvalue.
if (RefRelationship >= Sema::Ref_Related && isRValRef &&
Init->Classify(S.Context).isLValue()) {
ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, Init, DeclType);
return ICS;
}
// C++ [over.ics.ref]p2:
// When a parameter of reference type is not bound directly to
// an argument expression, the conversion sequence is the one
// required to convert the argument expression to the
// underlying type of the reference according to
// 13.3.3.1. Conceptually, this conversion sequence corresponds
// to copy-initializing a temporary of the underlying type with
// the argument expression. Any difference in top-level
// cv-qualification is subsumed by the initialization itself
// and does not constitute a conversion.
ICS = TryImplicitConversion(S, Init, T1, SuppressUserConversions,
AllowedExplicit::None,
/*InOverloadResolution=*/false,
/*CStyle=*/false,
/*AllowObjCWritebackConversion=*/false,
/*AllowObjCConversionOnExplicit=*/false);
// Of course, that's still a reference binding.
if (ICS.isStandard()) {
ICS.Standard.ReferenceBinding = true;
ICS.Standard.IsLvalueReference = !isRValRef;
ICS.Standard.BindsToFunctionLvalue = false;
ICS.Standard.BindsToRvalue = true;
ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
ICS.Standard.ObjCLifetimeConversionBinding = false;
} else if (ICS.isUserDefined()) {
const ReferenceType *LValRefType =
ICS.UserDefined.ConversionFunction->getReturnType()
->getAs<LValueReferenceType>();
// C++ [over.ics.ref]p3:
// Except for an implicit object parameter, for which see 13.3.1, a
// standard conversion sequence cannot be formed if it requires [...]
// binding an rvalue reference to an lvalue other than a function
// lvalue.
// Note that the function case is not possible here.
if (isRValRef && LValRefType) {
ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
return ICS;
}
ICS.UserDefined.After.ReferenceBinding = true;
ICS.UserDefined.After.IsLvalueReference = !isRValRef;
ICS.UserDefined.After.BindsToFunctionLvalue = false;
ICS.UserDefined.After.BindsToRvalue = !LValRefType;
ICS.UserDefined.After.BindsImplicitObjectArgumentWithoutRefQualifier = false;
ICS.UserDefined.After.ObjCLifetimeConversionBinding = false;
}
return ICS;
}
static ImplicitConversionSequence
TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
bool SuppressUserConversions,
bool InOverloadResolution,
bool AllowObjCWritebackConversion,
bool AllowExplicit = false);
/// TryListConversion - Try to copy-initialize a value of type ToType from the
/// initializer list From.
static ImplicitConversionSequence
TryListConversion(Sema &S, InitListExpr *From, QualType ToType,
bool SuppressUserConversions,
bool InOverloadResolution,
bool AllowObjCWritebackConversion) {
// C++11 [over.ics.list]p1:
// When an argument is an initializer list, it is not an expression and
// special rules apply for converting it to a parameter type.
ImplicitConversionSequence Result;
Result.setBad(BadConversionSequence::no_conversion, From, ToType);
// We need a complete type for what follows. With one C++20 exception,
// incomplete types can never be initialized from init lists.
QualType InitTy = ToType;
const ArrayType *AT = S.Context.getAsArrayType(ToType);
if (AT && S.getLangOpts().CPlusPlus20)
if (const auto *IAT = dyn_cast<IncompleteArrayType>(AT))
// C++20 allows list initialization of an incomplete array type.
InitTy = IAT->getElementType();
if (!S.isCompleteType(From->getBeginLoc(), InitTy))
return Result;
// Per DR1467:
// If the parameter type is a class X and the initializer list has a single
// element of type cv U, where U is X or a class derived from X, the
// implicit conversion sequence is the one required to convert the element
// to the parameter type.
//
// Otherwise, if the parameter type is a character array [... ]
// and the initializer list has a single element that is an
// appropriately-typed string literal (8.5.2 [dcl.init.string]), the
// implicit conversion sequence is the identity conversion.
if (From->getNumInits() == 1) {
if (ToType->isRecordType()) {
QualType InitType = From->getInit(0)->getType();
if (S.Context.hasSameUnqualifiedType(InitType, ToType) ||
S.IsDerivedFrom(From->getBeginLoc(), InitType, ToType))
return TryCopyInitialization(S, From->getInit(0), ToType,
SuppressUserConversions,
InOverloadResolution,
AllowObjCWritebackConversion);
}
if (AT && S.IsStringInit(From->getInit(0), AT)) {
InitializedEntity Entity =
InitializedEntity::InitializeParameter(S.Context, ToType,
/*Consumed=*/false);
if (S.CanPerformCopyInitialization(Entity, From)) {
Result.setStandard();
Result.Standard.setAsIdentityConversion();
Result.Standard.setFromType(ToType);
Result.Standard.setAllToTypes(ToType);
return Result;
}
}
}
// C++14 [over.ics.list]p2: Otherwise, if the parameter type [...] (below).
// C++11 [over.ics.list]p2:
// If the parameter type is std::initializer_list<X> or "array of X" and
// all the elements can be implicitly converted to X, the implicit
// conversion sequence is the worst conversion necessary to convert an
// element of the list to X.
//
// C++14 [over.ics.list]p3:
// Otherwise, if the parameter type is "array of N X", if the initializer
// list has exactly N elements or if it has fewer than N elements and X is
// default-constructible, and if all the elements of the initializer list
// can be implicitly converted to X, the implicit conversion sequence is
// the worst conversion necessary to convert an element of the list to X.
if (AT || S.isStdInitializerList(ToType, &InitTy)) {
unsigned e = From->getNumInits();
ImplicitConversionSequence DfltElt;
DfltElt.setBad(BadConversionSequence::no_conversion, QualType(),
QualType());
QualType ContTy = ToType;
bool IsUnbounded = false;
if (AT) {
InitTy = AT->getElementType();
if (ConstantArrayType const *CT = dyn_cast<ConstantArrayType>(AT)) {
if (CT->getSize().ult(e)) {
// Too many inits, fatally bad
Result.setBad(BadConversionSequence::too_many_initializers, From,
ToType);
Result.setInitializerListContainerType(ContTy, IsUnbounded);
return Result;
}
if (CT->getSize().ugt(e)) {
// Need an init from empty {}, is there one?
InitListExpr EmptyList(S.Context, From->getEndLoc(), None,
From->getEndLoc());
EmptyList.setType(S.Context.VoidTy);
DfltElt = TryListConversion(
S, &EmptyList, InitTy, SuppressUserConversions,
InOverloadResolution, AllowObjCWritebackConversion);
if (DfltElt.isBad()) {
// No {} init, fatally bad
Result.setBad(BadConversionSequence::too_few_initializers, From,
ToType);
Result.setInitializerListContainerType(ContTy, IsUnbounded);
return Result;
}
}
} else {
assert(isa<IncompleteArrayType>(AT) && "Expected incomplete array");
IsUnbounded = true;
if (!e) {
// Cannot convert to zero-sized.
Result.setBad(BadConversionSequence::too_few_initializers, From,
ToType);
Result.setInitializerListContainerType(ContTy, IsUnbounded);
return Result;
}
llvm::APInt Size(S.Context.getTypeSize(S.Context.getSizeType()), e);
ContTy = S.Context.getConstantArrayType(InitTy, Size, nullptr,
ArrayType::Normal, 0);
}
}
Result.setStandard();
Result.Standard.setAsIdentityConversion();
Result.Standard.setFromType(InitTy);
Result.Standard.setAllToTypes(InitTy);
for (unsigned i = 0; i < e; ++i) {
Expr *Init = From->getInit(i);
ImplicitConversionSequence ICS = TryCopyInitialization(
S, Init, InitTy, SuppressUserConversions, InOverloadResolution,
AllowObjCWritebackConversion);
// Keep the worse conversion seen so far.
// FIXME: Sequences are not totally ordered, so 'worse' can be
// ambiguous. CWG has been informed.
if (CompareImplicitConversionSequences(S, From->getBeginLoc(), ICS,
Result) ==
ImplicitConversionSequence::Worse) {
Result = ICS;
// Bail as soon as we find something unconvertible.
if (Result.isBad()) {
Result.setInitializerListContainerType(ContTy, IsUnbounded);
return Result;
}
}
}
// If we needed any implicit {} initialization, compare that now.
// over.ics.list/6 indicates we should compare that conversion. Again CWG
// has been informed that this might not be the best thing.
if (!DfltElt.isBad() && CompareImplicitConversionSequences(
S, From->getEndLoc(), DfltElt, Result) ==
ImplicitConversionSequence::Worse)
Result = DfltElt;
// Record the type being initialized so that we may compare sequences
Result.setInitializerListContainerType(ContTy, IsUnbounded);
return Result;
}
// C++14 [over.ics.list]p4:
// C++11 [over.ics.list]p3:
// Otherwise, if the parameter is a non-aggregate class X and overload
// resolution chooses a single best constructor [...] the implicit
// conversion sequence is a user-defined conversion sequence. If multiple
// constructors are viable but none is better than the others, the
// implicit conversion sequence is a user-defined conversion sequence.
if (ToType->isRecordType() && !ToType->isAggregateType()) {
// This function can deal with initializer lists.
return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions,
AllowedExplicit::None,
InOverloadResolution, /*CStyle=*/false,
AllowObjCWritebackConversion,
/*AllowObjCConversionOnExplicit=*/false);
}
// C++14 [over.ics.list]p5:
// C++11 [over.ics.list]p4:
// Otherwise, if the parameter has an aggregate type which can be
// initialized from the initializer list [...] the implicit conversion
// sequence is a user-defined conversion sequence.
if (ToType->isAggregateType()) {
// Type is an aggregate, argument is an init list. At this point it comes
// down to checking whether the initialization works.
// FIXME: Find out whether this parameter is consumed or not.
InitializedEntity Entity =
InitializedEntity::InitializeParameter(S.Context, ToType,
/*Consumed=*/false);
if (S.CanPerformAggregateInitializationForOverloadResolution(Entity,
From)) {
Result.setUserDefined();
Result.UserDefined.Before.setAsIdentityConversion();
// Initializer lists don't have a type.
Result.UserDefined.Before.setFromType(QualType());
Result.UserDefined.Before.setAllToTypes(QualType());
Result.UserDefined.After.setAsIdentityConversion();
Result.UserDefined.After.setFromType(ToType);
Result.UserDefined.After.setAllToTypes(ToType);
Result.UserDefined.ConversionFunction = nullptr;
}
return Result;
}
// C++14 [over.ics.list]p6:
// C++11 [over.ics.list]p5:
// Otherwise, if the parameter is a reference, see 13.3.3.1.4.
if (ToType->isReferenceType()) {
// The standard is notoriously unclear here, since 13.3.3.1.4 doesn't
// mention initializer lists in any way. So we go by what list-
// initialization would do and try to extrapolate from that.
QualType T1 = ToType->castAs<ReferenceType>()->getPointeeType();
// If the initializer list has a single element that is reference-related
// to the parameter type, we initialize the reference from that.
if (From->getNumInits() == 1) {
Expr *Init = From->getInit(0);
QualType T2 = Init->getType();
// If the initializer is the address of an overloaded function, try
// to resolve the overloaded function. If all goes well, T2 is the
// type of the resulting function.
if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
DeclAccessPair Found;
if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(
Init, ToType, false, Found))
T2 = Fn->getType();
}
// Compute some basic properties of the types and the initializer.
Sema::ReferenceCompareResult RefRelationship =
S.CompareReferenceRelationship(From->getBeginLoc(), T1, T2);
if (RefRelationship >= Sema::Ref_Related) {
return TryReferenceInit(S, Init, ToType, /*FIXME*/ From->getBeginLoc(),
SuppressUserConversions,
/*AllowExplicit=*/false);
}
}
// Otherwise, we bind the reference to a temporary created from the
// initializer list.
Result = TryListConversion(S, From, T1, SuppressUserConversions,
InOverloadResolution,
AllowObjCWritebackConversion);
if (Result.isFailure())
return Result;
assert(!Result.isEllipsis() &&
"Sub-initialization cannot result in ellipsis conversion.");
// Can we even bind to a temporary?
if (ToType->isRValueReferenceType() ||
(T1.isConstQualified() && !T1.isVolatileQualified())) {
StandardConversionSequence &SCS = Result.isStandard() ? Result.Standard :
Result.UserDefined.After;
SCS.ReferenceBinding = true;
SCS.IsLvalueReference = ToType->isLValueReferenceType();
SCS.BindsToRvalue = true;
SCS.BindsToFunctionLvalue = false;
SCS.BindsImplicitObjectArgumentWithoutRefQualifier = false;
SCS.ObjCLifetimeConversionBinding = false;
} else
Result.setBad(BadConversionSequence::lvalue_ref_to_rvalue,
From, ToType);
return Result;
}
// C++14 [over.ics.list]p7:
// C++11 [over.ics.list]p6:
// Otherwise, if the parameter type is not a class:
if (!ToType->isRecordType()) {
// - if the initializer list has one element that is not itself an
// initializer list, the implicit conversion sequence is the one
// required to convert the element to the parameter type.
unsigned NumInits = From->getNumInits();
if (NumInits == 1 && !isa<InitListExpr>(From->getInit(0)))
Result = TryCopyInitialization(S, From->getInit(0), ToType,
SuppressUserConversions,
InOverloadResolution,
AllowObjCWritebackConversion);
// - if the initializer list has no elements, the implicit conversion
// sequence is the identity conversion.
else if (NumInits == 0) {
Result.setStandard();
Result.Standard.setAsIdentityConversion();
Result.Standard.setFromType(ToType);
Result.Standard.setAllToTypes(ToType);
}
return Result;
}
// C++14 [over.ics.list]p8:
// C++11 [over.ics.list]p7:
// In all cases other than those enumerated above, no conversion is possible
return Result;
}
/// TryCopyInitialization - Try to copy-initialize a value of type
/// ToType from the expression From. Return the implicit conversion
/// sequence required to pass this argument, which may be a bad
/// conversion sequence (meaning that the argument cannot be passed to
/// a parameter of this type). If @p SuppressUserConversions, then we
/// do not permit any user-defined conversion sequences.
static ImplicitConversionSequence
TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
bool SuppressUserConversions,
bool InOverloadResolution,
bool AllowObjCWritebackConversion,
bool AllowExplicit) {
if (InitListExpr *FromInitList = dyn_cast<InitListExpr>(From))
return TryListConversion(S, FromInitList, ToType, SuppressUserConversions,
InOverloadResolution,AllowObjCWritebackConversion);
if (ToType->isReferenceType())
return TryReferenceInit(S, From, ToType,
/*FIXME:*/ From->getBeginLoc(),
SuppressUserConversions, AllowExplicit);
return TryImplicitConversion(S, From, ToType,
SuppressUserConversions,
AllowedExplicit::None,
InOverloadResolution,
/*CStyle=*/false,
AllowObjCWritebackConversion,
/*AllowObjCConversionOnExplicit=*/false);
}
static bool TryCopyInitialization(const CanQualType FromQTy,
const CanQualType ToQTy,
Sema &S,
SourceLocation Loc,
ExprValueKind FromVK) {
OpaqueValueExpr TmpExpr(Loc, FromQTy, FromVK);
ImplicitConversionSequence ICS =
TryCopyInitialization(S, &TmpExpr, ToQTy, true, true, false);
return !ICS.isBad();
}
/// TryObjectArgumentInitialization - Try to initialize the object
/// parameter of the given member function (@c Method) from the
/// expression @p From.
static ImplicitConversionSequence
TryObjectArgumentInitialization(Sema &S, SourceLocation Loc, QualType FromType,
Expr::Classification FromClassification,
CXXMethodDecl *Method,
CXXRecordDecl *ActingContext) {
QualType ClassType = S.Context.getTypeDeclType(ActingContext);
// [class.dtor]p2: A destructor can be invoked for a const, volatile or
// const volatile object.
Qualifiers Quals = Method->getMethodQualifiers();
if (isa<CXXDestructorDecl>(Method)) {
Quals.addConst();
Quals.addVolatile();
}
QualType ImplicitParamType = S.Context.getQualifiedType(ClassType, Quals);
// Set up the conversion sequence as a "bad" conversion, to allow us
// to exit early.
ImplicitConversionSequence ICS;
// We need to have an object of class type.
if (const PointerType *PT = FromType->getAs<PointerType>()) {
FromType = PT->getPointeeType();
// When we had a pointer, it's implicitly dereferenced, so we
// better have an lvalue.
assert(FromClassification.isLValue());
}
assert(FromType->isRecordType());
// C++0x [over.match.funcs]p4:
// For non-static member functions, the type of the implicit object
// parameter is
//
// - "lvalue reference to cv X" for functions declared without a
// ref-qualifier or with the & ref-qualifier
// - "rvalue reference to cv X" for functions declared with the &&
// ref-qualifier
//
// where X is the class of which the function is a member and cv is the
// cv-qualification on the member function declaration.
//
// However, when finding an implicit conversion sequence for the argument, we
// are not allowed to perform user-defined conversions
// (C++ [over.match.funcs]p5). We perform a simplified version of
// reference binding here, that allows class rvalues to bind to
// non-constant references.
// First check the qualifiers.
QualType FromTypeCanon = S.Context.getCanonicalType(FromType);
if (ImplicitParamType.getCVRQualifiers()
!= FromTypeCanon.getLocalCVRQualifiers() &&
!ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) {
ICS.setBad(BadConversionSequence::bad_qualifiers,
FromType, ImplicitParamType);
return ICS;
}
if (FromTypeCanon.hasAddressSpace()) {
Qualifiers QualsImplicitParamType = ImplicitParamType.getQualifiers();
Qualifiers QualsFromType = FromTypeCanon.getQualifiers();
if (!QualsImplicitParamType.isAddressSpaceSupersetOf(QualsFromType)) {
ICS.setBad(BadConversionSequence::bad_qualifiers,
FromType, ImplicitParamType);
return ICS;
}
}
// Check that we have either the same type or a derived type. It
// affects the conversion rank.
QualType ClassTypeCanon = S.Context.getCanonicalType(ClassType);
ImplicitConversionKind SecondKind;
if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) {
SecondKind = ICK_Identity;
} else if (S.IsDerivedFrom(Loc, FromType, ClassType))
SecondKind = ICK_Derived_To_Base;
else {
ICS.setBad(BadConversionSequence::unrelated_class,
FromType, ImplicitParamType);
return ICS;
}
// Check the ref-qualifier.
switch (Method->getRefQualifier()) {
case RQ_None:
// Do nothing; we don't care about lvalueness or rvalueness.
break;
case RQ_LValue:
if (!FromClassification.isLValue() && !Quals.hasOnlyConst()) {
// non-const lvalue reference cannot bind to an rvalue
ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, FromType,
ImplicitParamType);
return ICS;
}
break;
case RQ_RValue:
if (!FromClassification.isRValue()) {
// rvalue reference cannot bind to an lvalue
ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, FromType,
ImplicitParamType);
return ICS;
}
break;
}
// Success. Mark this as a reference binding.
ICS.setStandard();
ICS.Standard.setAsIdentityConversion();
ICS.Standard.Second = SecondKind;
ICS.Standard.setFromType(FromType);
ICS.Standard.setAllToTypes(ImplicitParamType);
ICS.Standard.ReferenceBinding = true;
ICS.Standard.DirectBinding = true;
ICS.Standard.IsLvalueReference = Method->getRefQualifier() != RQ_RValue;
ICS.Standard.BindsToFunctionLvalue = false;
ICS.Standard.BindsToRvalue = FromClassification.isRValue();
ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier
= (Method->getRefQualifier() == RQ_None);
return ICS;
}
/// PerformObjectArgumentInitialization - Perform initialization of
/// the implicit object parameter for the given Method with the given
/// expression.
ExprResult
Sema::PerformObjectArgumentInitialization(Expr *From,
NestedNameSpecifier *Qualifier,
NamedDecl *FoundDecl,
CXXMethodDecl *Method) {
QualType FromRecordType, DestType;
QualType ImplicitParamRecordType =
Method->getThisType()->castAs<PointerType>()->getPointeeType();
Expr::Classification FromClassification;
if (const PointerType *PT = From->getType()->getAs<PointerType>()) {
FromRecordType = PT->getPointeeType();
DestType = Method->getThisType();
FromClassification = Expr::Classification::makeSimpleLValue();
} else {
FromRecordType = From->getType();
DestType = ImplicitParamRecordType;
FromClassification = From->Classify(Context);
// When performing member access on a prvalue, materialize a temporary.
if (From->isPRValue()) {
From = CreateMaterializeTemporaryExpr(FromRecordType, From,
Method->getRefQualifier() !=
RefQualifierKind::RQ_RValue);
}
}
// Note that we always use the true parent context when performing
// the actual argument initialization.
ImplicitConversionSequence ICS = TryObjectArgumentInitialization(
*this, From->getBeginLoc(), From->getType(), FromClassification, Method,
Method->getParent());
if (ICS.isBad()) {
switch (ICS.Bad.Kind) {
case BadConversionSequence::bad_qualifiers: {
Qualifiers FromQs = FromRecordType.getQualifiers();
Qualifiers ToQs = DestType.getQualifiers();
unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
if (CVR) {
Diag(From->getBeginLoc(), diag::err_member_function_call_bad_cvr)
<< Method->getDeclName() << FromRecordType << (CVR - 1)
<< From->getSourceRange();
Diag(Method->getLocation(), diag::note_previous_decl)
<< Method->getDeclName();
return ExprError();
}
break;
}
case BadConversionSequence::lvalue_ref_to_rvalue:
case BadConversionSequence::rvalue_ref_to_lvalue: {
bool IsRValueQualified =
Method->getRefQualifier() == RefQualifierKind::RQ_RValue;
Diag(From->getBeginLoc(), diag::err_member_function_call_bad_ref)
<< Method->getDeclName() << FromClassification.isRValue()
<< IsRValueQualified;
Diag(Method->getLocation(), diag::note_previous_decl)
<< Method->getDeclName();
return ExprError();
}
case BadConversionSequence::no_conversion:
case BadConversionSequence::unrelated_class:
break;
case BadConversionSequence::too_few_initializers:
case BadConversionSequence::too_many_initializers:
llvm_unreachable("Lists are not objects");
}
return Diag(From->getBeginLoc(), diag::err_member_function_call_bad_type)
<< ImplicitParamRecordType << FromRecordType
<< From->getSourceRange();
}
if (ICS.Standard.Second == ICK_Derived_To_Base) {
ExprResult FromRes =
PerformObjectMemberConversion(From, Qualifier, FoundDecl, Method);
if (FromRes.isInvalid())
return ExprError();
From = FromRes.get();
}
if (!Context.hasSameType(From->getType(), DestType)) {
CastKind CK;
QualType PteeTy = DestType->getPointeeType();
LangAS DestAS =
PteeTy.isNull() ? DestType.getAddressSpace() : PteeTy.getAddressSpace();
if (FromRecordType.getAddressSpace() != DestAS)
CK = CK_AddressSpaceConversion;
else
CK = CK_NoOp;
From = ImpCastExprToType(From, DestType, CK, From->getValueKind()).get();
}
return From;
}
/// TryContextuallyConvertToBool - Attempt to contextually convert the
/// expression From to bool (C++0x [conv]p3).
static ImplicitConversionSequence
TryContextuallyConvertToBool(Sema &S, Expr *From) {
// C++ [dcl.init]/17.8:
// - Otherwise, if the initialization is direct-initialization, the source
// type is std::nullptr_t, and the destination type is bool, the initial
// value of the object being initialized is false.
if (From->getType()->isNullPtrType())
return ImplicitConversionSequence::getNullptrToBool(From->getType(),
S.Context.BoolTy,
From->isGLValue());
// All other direct-initialization of bool is equivalent to an implicit
// conversion to bool in which explicit conversions are permitted.
return TryImplicitConversion(S, From, S.Context.BoolTy,
/*SuppressUserConversions=*/false,
AllowedExplicit::Conversions,
/*InOverloadResolution=*/false,
/*CStyle=*/false,
/*AllowObjCWritebackConversion=*/false,
/*AllowObjCConversionOnExplicit=*/false);
}
/// PerformContextuallyConvertToBool - Perform a contextual conversion
/// of the expression From to bool (C++0x [conv]p3).
ExprResult Sema::PerformContextuallyConvertToBool(Expr *From) {
if (checkPlaceholderForOverload(*this, From))
return ExprError();
ImplicitConversionSequence ICS = TryContextuallyConvertToBool(*this, From);
if (!ICS.isBad())
return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting);
if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy))
return Diag(From->getBeginLoc(), diag::err_typecheck_bool_condition)
<< From->getType() << From->getSourceRange();
return ExprError();
}
/// Check that the specified conversion is permitted in a converted constant
/// expression, according to C++11 [expr.const]p3. Return true if the conversion
/// is acceptable.
static bool CheckConvertedConstantConversions(Sema &S,
StandardConversionSequence &SCS) {
// Since we know that the target type is an integral or unscoped enumeration
// type, most conversion kinds are impossible. All possible First and Third
// conversions are fine.
switch (SCS.Second) {
case ICK_Identity:
case ICK_Integral_Promotion:
case ICK_Integral_Conversion: // Narrowing conversions are checked elsewhere.
case ICK_Zero_Queue_Conversion:
return true;
case ICK_Boolean_Conversion:
// Conversion from an integral or unscoped enumeration type to bool is
// classified as ICK_Boolean_Conversion, but it's also arguably an integral
// conversion, so we allow it in a converted constant expression.
//
// FIXME: Per core issue 1407, we should not allow this, but that breaks
// a lot of popular code. We should at least add a warning for this
// (non-conforming) extension.
return SCS.getFromType()->isIntegralOrUnscopedEnumerationType() &&
SCS.getToType(2)->isBooleanType();
case ICK_Pointer_Conversion:
case ICK_Pointer_Member:
// C++1z: null pointer conversions and null member pointer conversions are
// only permitted if the source type is std::nullptr_t.
return SCS.getFromType()->isNullPtrType();
case ICK_Floating_Promotion:
case ICK_Complex_Promotion:
case ICK_Floating_Conversion:
case ICK_Complex_Conversion:
case ICK_Floating_Integral:
case ICK_Compatible_Conversion:
case ICK_Derived_To_Base:
case ICK_Vector_Conversion:
case ICK_SVE_Vector_Conversion:
case ICK_Vector_Splat:
case ICK_Complex_Real:
case ICK_Block_Pointer_Conversion:
case ICK_TransparentUnionConversion:
case ICK_Writeback_Conversion:
case ICK_Zero_Event_Conversion:
case ICK_C_Only_Conversion:
case ICK_Incompatible_Pointer_Conversion:
return false;
case ICK_Lvalue_To_Rvalue:
case ICK_Array_To_Pointer:
case ICK_Function_To_Pointer:
llvm_unreachable("found a first conversion kind in Second");
case ICK_Function_Conversion:
case ICK_Qualification:
llvm_unreachable("found a third conversion kind in Second");
case ICK_Num_Conversion_Kinds:
break;
}
llvm_unreachable("unknown conversion kind");
}
/// CheckConvertedConstantExpression - Check that the expression From is a
/// converted constant expression of type T, perform the conversion and produce
/// the converted expression, per C++11 [expr.const]p3.
static ExprResult CheckConvertedConstantExpression(Sema &S, Expr *From,
QualType T, APValue &Value,
Sema::CCEKind CCE,
bool RequireInt,
NamedDecl *Dest) {
assert(S.getLangOpts().CPlusPlus11 &&
"converted constant expression outside C++11");
if (checkPlaceholderForOverload(S, From))
return ExprError();
// C++1z [expr.const]p3:
// A converted constant expression of type T is an expression,
// implicitly converted to type T, where the converted
// expression is a constant expression and the implicit conversion
// sequence contains only [... list of conversions ...].
ImplicitConversionSequence ICS =
(CCE == Sema::CCEK_ExplicitBool || CCE == Sema::CCEK_Noexcept)
? TryContextuallyConvertToBool(S, From)
: TryCopyInitialization(S, From, T,
/*SuppressUserConversions=*/false,
/*InOverloadResolution=*/false,
/*AllowObjCWritebackConversion=*/false,
/*AllowExplicit=*/false);
StandardConversionSequence *SCS = nullptr;
switch (ICS.getKind()) {
case ImplicitConversionSequence::StandardConversion:
SCS = &ICS.Standard;
break;
case ImplicitConversionSequence::UserDefinedConversion:
if (T->isRecordType())
SCS = &ICS.UserDefined.Before;
else
SCS = &ICS.UserDefined.After;
break;
case ImplicitConversionSequence::AmbiguousConversion:
case ImplicitConversionSequence::BadConversion:
if (!S.DiagnoseMultipleUserDefinedConversion(From, T))
return S.Diag(From->getBeginLoc(),
diag::err_typecheck_converted_constant_expression)
<< From->getType() << From->getSourceRange() << T;
return ExprError();
case ImplicitConversionSequence::EllipsisConversion:
llvm_unreachable("ellipsis conversion in converted constant expression");
}
// Check that we would only use permitted conversions.
if (!CheckConvertedConstantConversions(S, *SCS)) {
return S.Diag(From->getBeginLoc(),
diag::err_typecheck_converted_constant_expression_disallowed)
<< From->getType() << From->getSourceRange() << T;
}
// [...] and where the reference binding (if any) binds directly.
if (SCS->ReferenceBinding && !SCS->DirectBinding) {
return S.Diag(From->getBeginLoc(),
diag::err_typecheck_converted_constant_expression_indirect)
<< From->getType() << From->getSourceRange() << T;
}
// Usually we can simply apply the ImplicitConversionSequence we formed
// earlier, but that's not guaranteed to work when initializing an object of
// class type.
ExprResult Result;
if (T->isRecordType()) {
assert(CCE == Sema::CCEK_TemplateArg &&
"unexpected class type converted constant expr");
Result = S.PerformCopyInitialization(
InitializedEntity::InitializeTemplateParameter(
T, cast<NonTypeTemplateParmDecl>(Dest)),
SourceLocation(), From);
} else {
Result = S.PerformImplicitConversion(From, T, ICS, Sema::AA_Converting);
}
if (Result.isInvalid())
return Result;
// C++2a [intro.execution]p5:
// A full-expression is [...] a constant-expression [...]
Result =
S.ActOnFinishFullExpr(Result.get(), From->getExprLoc(),
/*DiscardedValue=*/false, /*IsConstexpr=*/true);
if (Result.isInvalid())
return Result;
// Check for a narrowing implicit conversion.
bool ReturnPreNarrowingValue = false;
APValue PreNarrowingValue;
QualType PreNarrowingType;
switch (SCS->getNarrowingKind(S.Context, Result.get(), PreNarrowingValue,
PreNarrowingType)) {
case NK_Dependent_Narrowing:
// Implicit conversion to a narrower type, but the expression is
// value-dependent so we can't tell whether it's actually narrowing.
case NK_Variable_Narrowing:
// Implicit conversion to a narrower type, and the value is not a constant
// expression. We'll diagnose this in a moment.
case NK_Not_Narrowing:
break;
case NK_Constant_Narrowing:
if (CCE == Sema::CCEK_ArrayBound &&
PreNarrowingType->isIntegralOrEnumerationType() &&
PreNarrowingValue.isInt()) {
// Don't diagnose array bound narrowing here; we produce more precise
// errors by allowing the un-narrowed value through.
ReturnPreNarrowingValue = true;
break;
}
S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
<< CCE << /*Constant*/ 1
<< PreNarrowingValue.getAsString(S.Context, PreNarrowingType) << T;
break;
case NK_Type_Narrowing:
// FIXME: It would be better to diagnose that the expression is not a
// constant expression.
S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
<< CCE << /*Constant*/ 0 << From->getType() << T;
break;
}
if (Result.get()->isValueDependent()) {
Value = APValue();
return Result;
}
// Check the expression is a constant expression.
SmallVector<PartialDiagnosticAt, 8> Notes;
Expr::EvalResult Eval;
Eval.Diag = &Notes;
ConstantExprKind Kind;
if (CCE == Sema::CCEK_TemplateArg && T->isRecordType())
Kind = ConstantExprKind::ClassTemplateArgument;
else if (CCE == Sema::CCEK_TemplateArg)
Kind = ConstantExprKind::NonClassTemplateArgument;
else
Kind = ConstantExprKind::Normal;
if (!Result.get()->EvaluateAsConstantExpr(Eval, S.Context, Kind) ||
(RequireInt && !Eval.Val.isInt())) {
// The expression can't be folded, so we can't keep it at this position in
// the AST.
Result = ExprError();
} else {
Value = Eval.Val;
if (Notes.empty()) {
// It's a constant expression.
Expr *E = ConstantExpr::Create(S.Context, Result.get(), Value);
if (ReturnPreNarrowingValue)
Value = std::move(PreNarrowingValue);
return E;
}
}
// It's not a constant expression. Produce an appropriate diagnostic.
if (Notes.size() == 1 &&
Notes[0].second.getDiagID() == diag::note_invalid_subexpr_in_const_expr) {
S.Diag(Notes[0].first, diag::err_expr_not_cce) << CCE;
} else if (!Notes.empty() && Notes[0].second.getDiagID() ==
diag::note_constexpr_invalid_template_arg) {
Notes[0].second.setDiagID(diag::err_constexpr_invalid_template_arg);
for (unsigned I = 0; I < Notes.size(); ++I)
S.Diag(Notes[I].first, Notes[I].second);
} else {
S.Diag(From->getBeginLoc(), diag::err_expr_not_cce)
<< CCE << From->getSourceRange();
for (unsigned I = 0; I < Notes.size(); ++I)
S.Diag(Notes[I].first, Notes[I].second);
}
return ExprError();
}
ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
APValue &Value, CCEKind CCE,
NamedDecl *Dest) {
return ::CheckConvertedConstantExpression(*this, From, T, Value, CCE, false,
Dest);
}
ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
llvm::APSInt &Value,
CCEKind CCE) {
assert(T->isIntegralOrEnumerationType() && "unexpected converted const type");
APValue V;
auto R = ::CheckConvertedConstantExpression(*this, From, T, V, CCE, true,
/*Dest=*/nullptr);
if (!R.isInvalid() && !R.get()->isValueDependent())
Value = V.getInt();
return R;
}
/// dropPointerConversions - If the given standard conversion sequence
/// involves any pointer conversions, remove them. This may change
/// the result type of the conversion sequence.
static void dropPointerConversion(StandardConversionSequence &SCS) {
if (SCS.Second == ICK_Pointer_Conversion) {
SCS.Second = ICK_Identity;
SCS.Third = ICK_Identity;
SCS.ToTypePtrs[2] = SCS.ToTypePtrs[1] = SCS.ToTypePtrs[0];
}
}
/// TryContextuallyConvertToObjCPointer - Attempt to contextually
/// convert the expression From to an Objective-C pointer type.
static ImplicitConversionSequence
TryContextuallyConvertToObjCPointer(Sema &S, Expr *From) {
// Do an implicit conversion to 'id'.
QualType Ty = S.Context.getObjCIdType();
ImplicitConversionSequence ICS
= TryImplicitConversion(S, From, Ty,
// FIXME: Are these flags correct?
/*SuppressUserConversions=*/false,
AllowedExplicit::Conversions,
/*InOverloadResolution=*/false,
/*CStyle=*/false,
/*AllowObjCWritebackConversion=*/false,
/*AllowObjCConversionOnExplicit=*/true);
// Strip off any final conversions to 'id'.
switch (ICS.getKind()) {
case ImplicitConversionSequence::BadConversion:
case ImplicitConversionSequence::AmbiguousConversion:
case ImplicitConversionSequence::EllipsisConversion:
break;
case ImplicitConversionSequence::UserDefinedConversion:
dropPointerConversion(ICS.UserDefined.After);
break;
case ImplicitConversionSequence::StandardConversion:
dropPointerConversion(ICS.Standard);
break;
}
return ICS;
}
/// PerformContextuallyConvertToObjCPointer - Perform a contextual
/// conversion of the expression From to an Objective-C pointer type.
/// Returns a valid but null ExprResult if no conversion sequence exists.
ExprResult Sema::PerformContextuallyConvertToObjCPointer(Expr *From) {
if (checkPlaceholderForOverload(*this, From))
return ExprError();
QualType Ty = Context.getObjCIdType();
ImplicitConversionSequence ICS =
TryContextuallyConvertToObjCPointer(*this, From);
if (!ICS.isBad())
return PerformImplicitConversion(From, Ty, ICS, AA_Converting);
return ExprResult();
}
/// Determine whether the provided type is an integral type, or an enumeration
/// type of a permitted flavor.
bool Sema::ICEConvertDiagnoser::match(QualType T) {
return AllowScopedEnumerations ? T->isIntegralOrEnumerationType()
: T->isIntegralOrUnscopedEnumerationType();
}
static ExprResult
diagnoseAmbiguousConversion(Sema &SemaRef, SourceLocation Loc, Expr *From,
Sema::ContextualImplicitConverter &Converter,
QualType T, UnresolvedSetImpl &ViableConversions) {
if (Converter.Suppress)
return ExprError();
Converter.diagnoseAmbiguous(SemaRef, Loc, T) << From->getSourceRange();
for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
CXXConversionDecl *Conv =
cast<CXXConversionDecl>(ViableConversions[I]->getUnderlyingDecl());
QualType ConvTy = Conv->getConversionType().getNonReferenceType();
Converter.noteAmbiguous(SemaRef, Conv, ConvTy);
}
return From;
}
static bool
diagnoseNoViableConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From,
Sema::ContextualImplicitConverter &Converter,
QualType T, bool HadMultipleCandidates,
UnresolvedSetImpl &ExplicitConversions) {
if (ExplicitConversions.size() == 1 && !Converter.Suppress) {
DeclAccessPair Found = ExplicitConversions[0];
CXXConversionDecl *Conversion =
cast<CXXConversionDecl>(Found->getUnderlyingDecl());
// The user probably meant to invoke the given explicit
// conversion; use it.
QualType ConvTy = Conversion->getConversionType().getNonReferenceType();
std::string TypeStr;
ConvTy.getAsStringInternal(TypeStr, SemaRef.getPrintingPolicy());
Converter.diagnoseExplicitConv(SemaRef, Loc, T, ConvTy)
<< FixItHint::CreateInsertion(From->getBeginLoc(),
"static_cast<" + TypeStr + ">(")
<< FixItHint::CreateInsertion(
SemaRef.getLocForEndOfToken(From->getEndLoc()), ")");
Converter.noteExplicitConv(SemaRef, Conversion, ConvTy);
// If we aren't in a SFINAE context, build a call to the
// explicit conversion function.
if (SemaRef.isSFINAEContext())
return true;
SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found);
ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion,
HadMultipleCandidates);
if (Result.isInvalid())
return true;
// Record usage of conversion in an implicit cast.
From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(),
CK_UserDefinedConversion, Result.get(),
nullptr, Result.get()->getValueKind(),
SemaRef.CurFPFeatureOverrides());
}
return false;
}
static bool recordConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From,
Sema::ContextualImplicitConverter &Converter,
QualType T, bool HadMultipleCandidates,
DeclAccessPair &Found) {
CXXConversionDecl *Conversion =
cast<CXXConversionDecl>(Found->getUnderlyingDecl());
SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found);
QualType ToType = Conversion->getConversionType().getNonReferenceType();
if (!Converter.SuppressConversion) {
if (SemaRef.isSFINAEContext())
return true;
Converter.diagnoseConversion(SemaRef, Loc, T, ToType)
<< From->getSourceRange();
}
ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion,
HadMultipleCandidates);
if (Result.isInvalid())
return true;
// Record usage of conversion in an implicit cast.
From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(),
CK_UserDefinedConversion, Result.get(),
nullptr, Result.get()->getValueKind(),
SemaRef.CurFPFeatureOverrides());
return false;
}
static ExprResult finishContextualImplicitConversion(
Sema &SemaRef, SourceLocation Loc, Expr *From,
Sema::ContextualImplicitConverter &Converter) {
if (!Converter.match(From->getType()) && !Converter.Suppress)
Converter.diagnoseNoMatch(SemaRef, Loc, From->getType())
<< From->getSourceRange();
return SemaRef.DefaultLvalueConversion(From);
}
static void
collectViableConversionCandidates(Sema &SemaRef, Expr *From, QualType ToType,
UnresolvedSetImpl &ViableConversions,
OverloadCandidateSet &CandidateSet) {
for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
DeclAccessPair FoundDecl = ViableConversions[I];
NamedDecl *D = FoundDecl.getDecl();
CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
if (isa<UsingShadowDecl>(D))
D = cast<UsingShadowDecl>(D)->getTargetDecl();
CXXConversionDecl *Conv;
FunctionTemplateDecl *ConvTemplate;
if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D)))
Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
else
Conv = cast<CXXConversionDecl>(D);
if (ConvTemplate)
SemaRef.AddTemplateConversionCandidate(
ConvTemplate, FoundDecl, ActingContext, From, ToType, CandidateSet,
/*AllowObjCConversionOnExplicit=*/false, /*AllowExplicit*/ true);
else
SemaRef.AddConversionCandidate(Conv, FoundDecl, ActingContext, From,
ToType, CandidateSet,
/*AllowObjCConversionOnExplicit=*/false,
/*AllowExplicit*/ true);
}
}
/// Attempt to convert the given expression to a type which is accepted
/// by the given converter.
///
/// This routine will attempt to convert an expression of class type to a
/// type accepted by the specified converter. In C++11 and before, the class
/// must have a single non-explicit conversion function converting to a matching
/// type. In C++1y, there can be multiple such conversion functions, but only
/// one target type.
///
/// \param Loc The source location of the construct that requires the
/// conversion.
///
/// \param From The expression we're converting from.
///
/// \param Converter Used to control and diagnose the conversion process.
///
/// \returns The expression, converted to an integral or enumeration type if
/// successful.
ExprResult Sema::PerformContextualImplicitConversion(
SourceLocation Loc, Expr *From, ContextualImplicitConverter &Converter) {
// We can't perform any more checking for type-dependent expressions.
if (From->isTypeDependent())
return From;
// Process placeholders immediately.
if (From->hasPlaceholderType()) {
ExprResult result = CheckPlaceholderExpr(From);
if (result.isInvalid())
return result;
From = result.get();
}
// If the expression already has a matching type, we're golden.
QualType T = From->getType();
if (Converter.match(T))
return DefaultLvalueConversion(From);
// FIXME: Check for missing '()' if T is a function type?
// We can only perform contextual implicit conversions on objects of class
// type.
const RecordType *RecordTy = T->getAs<RecordType>();
if (!RecordTy || !getLangOpts().CPlusPlus) {
if (!Converter.Suppress)
Converter.diagnoseNoMatch(*this, Loc, T) << From->getSourceRange();
return From;
}
// We must have a complete class type.
struct TypeDiagnoserPartialDiag : TypeDiagnoser {
ContextualImplicitConverter &Converter;
Expr *From;
TypeDiagnoserPartialDiag(ContextualImplicitConverter &Converter, Expr *From)
: Converter(Converter), From(From) {}
void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
Converter.diagnoseIncomplete(S, Loc, T) << From->getSourceRange();
}
} IncompleteDiagnoser(Converter, From);
if (Converter.Suppress ? !isCompleteType(Loc, T)
: RequireCompleteType(Loc, T, IncompleteDiagnoser))
return From;
// Look for a conversion to an integral or enumeration type.
UnresolvedSet<4>
ViableConversions; // These are *potentially* viable in C++1y.
UnresolvedSet<4> ExplicitConversions;
const auto &Conversions =
cast<CXXRecordDecl>(RecordTy->getDecl())->getVisibleConversionFunctions();
bool HadMultipleCandidates =
(std::distance(Conversions.begin(), Conversions.end()) > 1);
// To check that there is only one target type, in C++1y:
QualType ToType;
bool HasUniqueTargetType = true;
// Collect explicit or viable (potentially in C++1y) conversions.
for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
NamedDecl *D = (*I)->getUnderlyingDecl();
CXXConversionDecl *Conversion;
FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
if (ConvTemplate) {
if (getLangOpts().CPlusPlus14)
Conversion = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
else
continue; // C++11 does not consider conversion operator templates(?).
} else
Conversion = cast<CXXConversionDecl>(D);
assert((!ConvTemplate || getLangOpts().CPlusPlus14) &&
"Conversion operator templates are considered potentially "
"viable in C++1y");
QualType CurToType = Conversion->getConversionType().getNonReferenceType();
if (Converter.match(CurToType) || ConvTemplate) {
if (Conversion->isExplicit()) {
// FIXME: For C++1y, do we need this restriction?
// cf. diagnoseNoViableConversion()
if (!ConvTemplate)
ExplicitConversions.addDecl(I.getDecl(), I.getAccess());
} else {
if (!ConvTemplate && getLangOpts().CPlusPlus14) {
if (ToType.isNull())
ToType = CurToType.getUnqualifiedType();
else if (HasUniqueTargetType &&
(CurToType.getUnqualifiedType() != ToType))
HasUniqueTargetType = false;
}
ViableConversions.addDecl(I.getDecl(), I.getAccess());
}
}
}
if (getLangOpts().CPlusPlus14) {
// C++1y [conv]p6:
// ... An expression e of class type E appearing in such a context
// is said to be contextually implicitly converted to a specified
// type T and is well-formed if and only if e can be implicitly
// converted to a type T that is determined as follows: E is searched
// for conversion functions whose return type is cv T or reference to
// cv T such that T is allowed by the context. There shall be
// exactly one such T.
// If no unique T is found:
if (ToType.isNull()) {
if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
HadMultipleCandidates,
ExplicitConversions))
return ExprError();
return finishContextualImplicitConversion(*this, Loc, From, Converter);
}
// If more than one unique Ts are found:
if (!HasUniqueTargetType)
return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
ViableConversions);
// If one unique T is found:
// First, build a candidate set from the previously recorded
// potentially viable conversions.
OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
collectViableConversionCandidates(*this, From, ToType, ViableConversions,
CandidateSet);
// Then, perform overload resolution over the candidate set.
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(*this, Loc, Best)) {
case OR_Success: {
// Apply this conversion.
DeclAccessPair Found =
DeclAccessPair::make(Best->Function, Best->FoundDecl.getAccess());
if (recordConversion(*this, Loc, From, Converter, T,
HadMultipleCandidates, Found))
return ExprError();
break;
}
case OR_Ambiguous:
return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
ViableConversions);
case OR_No_Viable_Function:
if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
HadMultipleCandidates,
ExplicitConversions))
return ExprError();
LLVM_FALLTHROUGH;
case OR_Deleted:
// We'll complain below about a non-integral condition type.
break;
}
} else {
switch (ViableConversions.size()) {
case 0: {
if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
HadMultipleCandidates,
ExplicitConversions))
return ExprError();
// We'll complain below about a non-integral condition type.
break;
}
case 1: {
// Apply this conversion.
DeclAccessPair Found = ViableConversions[0];
if (recordConversion(*this, Loc, From, Converter, T,
HadMultipleCandidates, Found))
return ExprError();
break;
}
default:
return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
ViableConversions);
}
}
return finishContextualImplicitConversion(*this, Loc, From, Converter);
}
/// IsAcceptableNonMemberOperatorCandidate - Determine whether Fn is
/// an acceptable non-member overloaded operator for a call whose
/// arguments have types T1 (and, if non-empty, T2). This routine
/// implements the check in C++ [over.match.oper]p3b2 concerning
/// enumeration types.
static bool IsAcceptableNonMemberOperatorCandidate(ASTContext &Context,
FunctionDecl *Fn,
ArrayRef<Expr *> Args) {
QualType T1 = Args[0]->getType();
QualType T2 = Args.size() > 1 ? Args[1]->getType() : QualType();
if (T1->isDependentType() || (!T2.isNull() && T2->isDependentType()))
return true;
if (T1->isRecordType() || (!T2.isNull() && T2->isRecordType()))
return true;
const auto *Proto = Fn->getType()->castAs<FunctionProtoType>();
if (Proto->getNumParams() < 1)
return false;
if (T1->isEnumeralType()) {
QualType ArgType = Proto->getParamType(0).getNonReferenceType();
if (Context.hasSameUnqualifiedType(T1, ArgType))
return true;
}
if (Proto->getNumParams() < 2)
return false;
if (!T2.isNull() && T2->isEnumeralType()) {
QualType ArgType = Proto->getParamType(1).getNonReferenceType();
if (Context.hasSameUnqualifiedType(T2, ArgType))
return true;
}
return false;
}
/// AddOverloadCandidate - Adds the given function to the set of
/// candidate functions, using the given function call arguments. If
/// @p SuppressUserConversions, then don't allow user-defined
/// conversions via constructors or conversion operators.
///
/// \param PartialOverloading true if we are performing "partial" overloading
/// based on an incomplete set of function arguments. This feature is used by
/// code completion.
void Sema::AddOverloadCandidate(
FunctionDecl *Function, DeclAccessPair FoundDecl, ArrayRef<Expr *> Args,
OverloadCandidateSet &CandidateSet, bool SuppressUserConversions,
bool PartialOverloading, bool AllowExplicit, bool AllowExplicitConversions,
ADLCallKind IsADLCandidate, ConversionSequenceList EarlyConversions,
OverloadCandidateParamOrder PO) {
const FunctionProtoType *Proto
= dyn_cast<FunctionProtoType>(Function->getType()->getAs<FunctionType>());
assert(Proto && "Functions without a prototype cannot be overloaded");
assert(!Function->getDescribedFunctionTemplate() &&
"Use AddTemplateOverloadCandidate for function templates");
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) {
if (!isa<CXXConstructorDecl>(Method)) {
// If we get here, it's because we're calling a member function
// that is named without a member access expression (e.g.,
// "this->f") that was either written explicitly or created
// implicitly. This can happen with a qualified call to a member
// function, e.g., X::f(). We use an empty type for the implied
// object argument (C++ [over.call.func]p3), and the acting context
// is irrelevant.
AddMethodCandidate(Method, FoundDecl, Method->getParent(), QualType(),
Expr::Classification::makeSimpleLValue(), Args,
CandidateSet, SuppressUserConversions,
PartialOverloading, EarlyConversions, PO);
return;
}
// We treat a constructor like a non-member function, since its object
// argument doesn't participate in overload resolution.
}
if (!CandidateSet.isNewCandidate(Function, PO))
return;
// C++11 [class.copy]p11: [DR1402]
// A defaulted move constructor that is defined as deleted is ignored by
// overload resolution.
CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Function);
if (Constructor && Constructor->isDefaulted() && Constructor->isDeleted() &&
Constructor->isMoveConstructor())
return;
// Overload resolution is always an unevaluated context.
EnterExpressionEvaluationContext Unevaluated(
*this, Sema::ExpressionEvaluationContext::Unevaluated);
// C++ [over.match.oper]p3:
// if no operand has a class type, only those non-member functions in the
// lookup set that have a first parameter of type T1 or "reference to
// (possibly cv-qualified) T1", when T1 is an enumeration type, or (if there
// is a right operand) a second parameter of type T2 or "reference to
// (possibly cv-qualified) T2", when T2 is an enumeration type, are
// candidate functions.
if (CandidateSet.getKind() == OverloadCandidateSet::CSK_Operator &&
!IsAcceptableNonMemberOperatorCandidate(Context, Function, Args))
return;
// Add this candidate
OverloadCandidate &Candidate =
CandidateSet.addCandidate(Args.size(), EarlyConversions);
Candidate.FoundDecl = FoundDecl;
Candidate.Function = Function;
Candidate.Viable = true;
Candidate.RewriteKind =
CandidateSet.getRewriteInfo().getRewriteKind(Function, PO);
Candidate.IsSurrogate = false;
Candidate.IsADLCandidate = IsADLCandidate;
Candidate.IgnoreObjectArgument = false;
Candidate.ExplicitCallArguments = Args.size();
// Explicit functions are not actually candidates at all if we're not
// allowing them in this context, but keep them around so we can point
// to them in diagnostics.
if (!AllowExplicit && ExplicitSpecifier::getFromDecl(Function).isExplicit()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_explicit;
return;
}
if (Function->isMultiVersion() && Function->hasAttr<TargetAttr>() &&
!Function->getAttr<TargetAttr>()->isDefaultVersion()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_non_default_multiversion_function;
return;
}
if (Constructor) {
// C++ [class.copy]p3:
// A member function template is never instantiated to perform the copy
// of a class object to an object of its class type.
QualType ClassType = Context.getTypeDeclType(Constructor->getParent());
if (Args.size() == 1 && Constructor->isSpecializationCopyingObject() &&
(Context.hasSameUnqualifiedType(ClassType, Args[0]->getType()) ||
IsDerivedFrom(Args[0]->getBeginLoc(), Args[0]->getType(),
ClassType))) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_illegal_constructor;
return;
}
// C++ [over.match.funcs]p8: (proposed DR resolution)
// A constructor inherited from class type C that has a first parameter
// of type "reference to P" (including such a constructor instantiated
// from a template) is excluded from the set of candidate functions when
// constructing an object of type cv D if the argument list has exactly
// one argument and D is reference-related to P and P is reference-related
// to C.
auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(FoundDecl.getDecl());
if (Shadow && Args.size() == 1 && Constructor->getNumParams() >= 1 &&
Constructor->getParamDecl(0)->getType()->isReferenceType()) {
QualType P = Constructor->getParamDecl(0)->getType()->getPointeeType();
QualType C = Context.getRecordType(Constructor->getParent());
QualType D = Context.getRecordType(Shadow->getParent());
SourceLocation Loc = Args.front()->getExprLoc();
if ((Context.hasSameUnqualifiedType(P, C) || IsDerivedFrom(Loc, P, C)) &&
(Context.hasSameUnqualifiedType(D, P) || IsDerivedFrom(Loc, D, P))) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_inhctor_slice;
return;
}
}
// Check that the constructor is capable of constructing an object in the
// destination address space.
if (!Qualifiers::isAddressSpaceSupersetOf(
Constructor->getMethodQualifiers().getAddressSpace(),
CandidateSet.getDestAS())) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_object_addrspace_mismatch;
}
}
unsigned NumParams = Proto->getNumParams();
// (C++ 13.3.2p2): A candidate function having fewer than m
// parameters is viable only if it has an ellipsis in its parameter
// list (8.3.5).
if (TooManyArguments(NumParams, Args.size(), PartialOverloading) &&
!Proto->isVariadic()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_too_many_arguments;
return;
}
// (C++ 13.3.2p2): A candidate function having more than m parameters
// is viable only if the (m+1)st parameter has a default argument
// (8.3.6). For the purposes of overload resolution, the
// parameter list is truncated on the right, so that there are
// exactly m parameters.
unsigned MinRequiredArgs = Function->getMinRequiredArguments();
if (Args.size() < MinRequiredArgs && !PartialOverloading) {
// Not enough arguments.
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_too_few_arguments;
return;
}
// (CUDA B.1): Check for invalid calls between targets.
if (getLangOpts().CUDA)
if (const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext))
// Skip the check for callers that are implicit members, because in this
// case we may not yet know what the member's target is; the target is
// inferred for the member automatically, based on the bases and fields of
// the class.
if (!Caller->isImplicit() && !IsAllowedCUDACall(Caller, Function)) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_bad_target;
return;
}
if (Function->getTrailingRequiresClause()) {
ConstraintSatisfaction Satisfaction;
if (CheckFunctionConstraints(Function, Satisfaction) ||
!Satisfaction.IsSatisfied) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_constraints_not_satisfied;
return;
}
}
// Determine the implicit conversion sequences for each of the
// arguments.
for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) {
unsigned ConvIdx =
PO == OverloadCandidateParamOrder::Reversed ? 1 - ArgIdx : ArgIdx;
if (Candidate.Conversions[ConvIdx].isInitialized()) {
// We already formed a conversion sequence for this parameter during
// template argument deduction.
} else if (ArgIdx < NumParams) {
// (C++ 13.3.2p3): for F to be a viable function, there shall
// exist for each argument an implicit conversion sequence
// (13.3.3.1) that converts that argument to the corresponding
// parameter of F.
QualType ParamType = Proto->getParamType(ArgIdx);
Candidate.Conversions[ConvIdx] = TryCopyInitialization(
*this, Args[ArgIdx], ParamType, SuppressUserConversions,
/*InOverloadResolution=*/true,
/*AllowObjCWritebackConversion=*/
getLangOpts().ObjCAutoRefCount, AllowExplicitConversions);
if (Candidate.Conversions[ConvIdx].isBad()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_bad_conversion;
return;
}
} else {
// (C++ 13.3.2p2): For the purposes of overload resolution, any
// argument for which there is no corresponding parameter is
// considered to ""match the ellipsis" (C+ 13.3.3.1.3).
Candidate.Conversions[ConvIdx].setEllipsis();
}
}
if (EnableIfAttr *FailedAttr =
CheckEnableIf(Function, CandidateSet.getLocation(), Args)) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_enable_if;
Candidate.DeductionFailure.Data = FailedAttr;
return;
}
}
ObjCMethodDecl *
Sema::SelectBestMethod(Selector Sel, MultiExprArg Args, bool IsInstance,
SmallVectorImpl<ObjCMethodDecl *> &Methods) {
if (Methods.size() <= 1)
return nullptr;
for (unsigned b = 0, e = Methods.size(); b < e; b++) {
bool Match = true;
ObjCMethodDecl *Method = Methods[b];
unsigned NumNamedArgs = Sel.getNumArgs();
// Method might have more arguments than selector indicates. This is due
// to addition of c-style arguments in method.
if (Method->param_size() > NumNamedArgs)
NumNamedArgs = Method->param_size();
if (Args.size() < NumNamedArgs)
continue;
for (unsigned i = 0; i < NumNamedArgs; i++) {
// We can't do any type-checking on a type-dependent argument.
if (Args[i]->isTypeDependent()) {
Match = false;
break;
}
ParmVarDecl *param = Method->parameters()[i];
Expr *argExpr = Args[i];
assert(argExpr && "SelectBestMethod(): missing expression");
// Strip the unbridged-cast placeholder expression off unless it's
// a consumed argument.
if (argExpr->hasPlaceholderType(BuiltinType::ARCUnbridgedCast) &&
!param->hasAttr<CFConsumedAttr>())
argExpr = stripARCUnbridgedCast(argExpr);
// If the parameter is __unknown_anytype, move on to the next method.
if (param->getType() == Context.UnknownAnyTy) {
Match = false;
break;
}
ImplicitConversionSequence ConversionState
= TryCopyInitialization(*this, argExpr, param->getType(),
/*SuppressUserConversions*/false,
/*InOverloadResolution=*/true,
/*AllowObjCWritebackConversion=*/
getLangOpts().ObjCAutoRefCount,
/*AllowExplicit*/false);
// This function looks for a reasonably-exact match, so we consider
// incompatible pointer conversions to be a failure here.
if (ConversionState.isBad() ||
(ConversionState.isStandard() &&
ConversionState.Standard.Second ==
ICK_Incompatible_Pointer_Conversion)) {
Match = false;
break;
}
}
// Promote additional arguments to variadic methods.
if (Match && Method->isVariadic()) {
for (unsigned i = NumNamedArgs, e = Args.size(); i < e; ++i) {
if (Args[i]->isTypeDependent()) {
Match = false;
break;
}
ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
nullptr);
if (Arg.isInvalid()) {
Match = false;
break;
}
}
} else {
// Check for extra arguments to non-variadic methods.
if (Args.size() != NumNamedArgs)
Match = false;
else if (Match && NumNamedArgs == 0 && Methods.size() > 1) {
// Special case when selectors have no argument. In this case, select
// one with the most general result type of 'id'.
for (unsigned b = 0, e = Methods.size(); b < e; b++) {
QualType ReturnT = Methods[b]->getReturnType();
if (ReturnT->isObjCIdType())
return Methods[b];
}
}
}
if (Match)
return Method;
}
return nullptr;
}
static bool convertArgsForAvailabilityChecks(
Sema &S, FunctionDecl *Function, Expr *ThisArg, SourceLocation CallLoc,
ArrayRef<Expr *> Args, Sema::SFINAETrap &Trap, bool MissingImplicitThis,
Expr *&ConvertedThis, SmallVectorImpl<Expr *> &ConvertedArgs) {
if (ThisArg) {
CXXMethodDecl *Method = cast<CXXMethodDecl>(Function);
assert(!isa<CXXConstructorDecl>(Method) &&
"Shouldn't have `this` for ctors!");
assert(!Method->isStatic() && "Shouldn't have `this` for static methods!");
ExprResult R = S.PerformObjectArgumentInitialization(
ThisArg, /*Qualifier=*/nullptr, Method, Method);
if (R.isInvalid())
return false;
ConvertedThis = R.get();
} else {
if (auto *MD = dyn_cast<CXXMethodDecl>(Function)) {
(void)MD;
assert((MissingImplicitThis || MD->isStatic() ||
isa<CXXConstructorDecl>(MD)) &&
"Expected `this` for non-ctor instance methods");
}
ConvertedThis = nullptr;
}
// Ignore any variadic arguments. Converting them is pointless, since the
// user can't refer to them in the function condition.
unsigned ArgSizeNoVarargs = std::min(Function->param_size(), Args.size());
// Convert the arguments.
for (unsigned I = 0; I != ArgSizeNoVarargs; ++I) {
ExprResult R;
R = S.PerformCopyInitialization(InitializedEntity::InitializeParameter(
S.Context, Function->getParamDecl(I)),
SourceLocation(), Args[I]);
if (R.isInvalid())
return false;
ConvertedArgs.push_back(R.get());
}
if (Trap.hasErrorOccurred())
return false;
// Push default arguments if needed.
if (!Function->isVariadic() && Args.size() < Function->getNumParams()) {
for (unsigned i = Args.size(), e = Function->getNumParams(); i != e; ++i) {
ParmVarDecl *P = Function->getParamDecl(i);
if (!P->hasDefaultArg())
return false;
ExprResult R = S.BuildCXXDefaultArgExpr(CallLoc, Function, P);
if (R.isInvalid())
return false;
ConvertedArgs.push_back(R.get());
}
if (Trap.hasErrorOccurred())
return false;
}
return true;
}
EnableIfAttr *Sema::CheckEnableIf(FunctionDecl *Function,
SourceLocation CallLoc,
ArrayRef<Expr *> Args,
bool MissingImplicitThis) {
auto EnableIfAttrs = Function->specific_attrs<EnableIfAttr>();
if (EnableIfAttrs.begin() == EnableIfAttrs.end())
return nullptr;
SFINAETrap Trap(*this);
SmallVector<Expr *, 16> ConvertedArgs;
// FIXME: We should look into making enable_if late-parsed.
Expr *DiscardedThis;
if (!convertArgsForAvailabilityChecks(
*this, Function, /*ThisArg=*/nullptr, CallLoc, Args, Trap,
/*MissingImplicitThis=*/true, DiscardedThis, ConvertedArgs))
return *EnableIfAttrs.begin();
for (auto *EIA : EnableIfAttrs) {
APValue Result;
// FIXME: This doesn't consider value-dependent cases, because doing so is
// very difficult. Ideally, we should handle them more gracefully.
if (EIA->getCond()->isValueDependent() ||
!EIA->getCond()->EvaluateWithSubstitution(
Result, Context, Function, llvm::makeArrayRef(ConvertedArgs)))
return EIA;
if (!Result.isInt() || !Result.getInt().getBoolValue())
return EIA;
}
return nullptr;
}
template <typename CheckFn>
static bool diagnoseDiagnoseIfAttrsWith(Sema &S, const NamedDecl *ND,
bool ArgDependent, SourceLocation Loc,
CheckFn &&IsSuccessful) {
SmallVector<const DiagnoseIfAttr *, 8> Attrs;
for (const auto *DIA : ND->specific_attrs<DiagnoseIfAttr>()) {
if (ArgDependent == DIA->getArgDependent())
Attrs.push_back(DIA);
}
// Common case: No diagnose_if attributes, so we can quit early.
if (Attrs.empty())
return false;
auto WarningBegin = std::stable_partition(
Attrs.begin(), Attrs.end(),
[](const DiagnoseIfAttr *DIA) { return DIA->isError(); });
// Note that diagnose_if attributes are late-parsed, so they appear in the
// correct order (unlike enable_if attributes).
auto ErrAttr = llvm::find_if(llvm::make_range(Attrs.begin(), WarningBegin),
IsSuccessful);
if (ErrAttr != WarningBegin) {
const DiagnoseIfAttr *DIA = *ErrAttr;
S.Diag(Loc, diag::err_diagnose_if_succeeded) << DIA->getMessage();
S.Diag(DIA->getLocation(), diag::note_from_diagnose_if)
<< DIA->getParent() << DIA->getCond()->getSourceRange();
return true;
}
for (const auto *DIA : llvm::make_range(WarningBegin, Attrs.end()))
if (IsSuccessful(DIA)) {
S.Diag(Loc, diag::warn_diagnose_if_succeeded) << DIA->getMessage();
S.Diag(DIA->getLocation(), diag::note_from_diagnose_if)
<< DIA->getParent() << DIA->getCond()->getSourceRange();
}
return false;
}
bool Sema::diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function,
const Expr *ThisArg,
ArrayRef<const Expr *> Args,
SourceLocation Loc) {
return diagnoseDiagnoseIfAttrsWith(
*this, Function, /*ArgDependent=*/true, Loc,
[&](const DiagnoseIfAttr *DIA) {
APValue Result;
// It's sane to use the same Args for any redecl of this function, since
// EvaluateWithSubstitution only cares about the position of each
// argument in the arg list, not the ParmVarDecl* it maps to.
if (!DIA->getCond()->EvaluateWithSubstitution(
Result, Context, cast<FunctionDecl>(DIA->getParent()), Args, ThisArg))
return false;
return Result.isInt() && Result.getInt().getBoolValue();
});
}
bool Sema::diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl *ND,
SourceLocation Loc) {
return diagnoseDiagnoseIfAttrsWith(
*this, ND, /*ArgDependent=*/false, Loc,
[&](const DiagnoseIfAttr *DIA) {
bool Result;
return DIA->getCond()->EvaluateAsBooleanCondition(Result, Context) &&
Result;
});
}
/// Add all of the function declarations in the given function set to
/// the overload candidate set.
void Sema::AddFunctionCandidates(const UnresolvedSetImpl &Fns,
ArrayRef<Expr *> Args,
OverloadCandidateSet &CandidateSet,
TemplateArgumentListInfo *ExplicitTemplateArgs,
bool SuppressUserConversions,
bool PartialOverloading,
bool FirstArgumentIsBase) {
for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) {
NamedDecl *D = F.getDecl()->getUnderlyingDecl();
ArrayRef<Expr *> FunctionArgs = Args;
FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D);
FunctionDecl *FD =
FunTmpl ? FunTmpl->getTemplatedDecl() : cast<FunctionDecl>(D);
if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic()) {
QualType ObjectType;
Expr::Classification ObjectClassification;
if (Args.size() > 0) {
if (Expr *E = Args[0]) {
// Use the explicit base to restrict the lookup:
ObjectType = E->getType();
// Pointers in the object arguments are implicitly dereferenced, so we
// always classify them as l-values.
if (!ObjectType.isNull() && ObjectType->isPointerType())
ObjectClassification = Expr::Classification::makeSimpleLValue();
else
ObjectClassification = E->Classify(Context);
} // .. else there is an implicit base.
FunctionArgs = Args.slice(1);
}
if (FunTmpl) {
AddMethodTemplateCandidate(
FunTmpl, F.getPair(),
cast<CXXRecordDecl>(FunTmpl->getDeclContext()),
ExplicitTemplateArgs, ObjectType, ObjectClassification,
FunctionArgs, CandidateSet, SuppressUserConversions,
PartialOverloading);
} else {
AddMethodCandidate(cast<CXXMethodDecl>(FD), F.getPair(),
cast<CXXMethodDecl>(FD)->getParent(), ObjectType,
ObjectClassification, FunctionArgs, CandidateSet,
SuppressUserConversions, PartialOverloading);
}
} else {
// This branch handles both standalone functions and static methods.
// Slice the first argument (which is the base) when we access
// static method as non-static.
if (Args.size() > 0 &&
(!Args[0] || (FirstArgumentIsBase && isa<CXXMethodDecl>(FD) &&
!isa<CXXConstructorDecl>(FD)))) {
assert(cast<CXXMethodDecl>(FD)->isStatic());
FunctionArgs = Args.slice(1);
}
if (FunTmpl) {
AddTemplateOverloadCandidate(FunTmpl, F.getPair(),
ExplicitTemplateArgs, FunctionArgs,
CandidateSet, SuppressUserConversions,
PartialOverloading);
} else {
AddOverloadCandidate(FD, F.getPair(), FunctionArgs, CandidateSet,
SuppressUserConversions, PartialOverloading);
}
}
}
}
/// AddMethodCandidate - Adds a named decl (which is some kind of
/// method) as a method candidate to the given overload set.
void Sema::AddMethodCandidate(DeclAccessPair FoundDecl, QualType ObjectType,
Expr::Classification ObjectClassification,
ArrayRef<Expr *> Args,
OverloadCandidateSet &CandidateSet,
bool SuppressUserConversions,
OverloadCandidateParamOrder PO) {
NamedDecl *Decl = FoundDecl.getDecl();
CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(Decl->getDeclContext());
if (isa<UsingShadowDecl>(Decl))
Decl = cast<UsingShadowDecl>(Decl)->getTargetDecl();
if (FunctionTemplateDecl *TD = dyn_cast<FunctionTemplateDecl>(Decl)) {
assert(isa<CXXMethodDecl>(TD->getTemplatedDecl()) &&
"Expected a member function template");
AddMethodTemplateCandidate(TD, FoundDecl, ActingContext,
/*ExplicitArgs*/ nullptr, ObjectType,
ObjectClassification, Args, CandidateSet,
SuppressUserConversions, false, PO);
} else {
AddMethodCandidate(cast<CXXMethodDecl>(Decl), FoundDecl, ActingContext,
ObjectType, ObjectClassification, Args, CandidateSet,
SuppressUserConversions, false, None, PO);
}
}
/// AddMethodCandidate - Adds the given C++ member function to the set
/// of candidate functions, using the given function call arguments
/// and the object argument (@c Object). For example, in a call
/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain
/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't
/// allow user-defined conversions via constructors or conversion
/// operators.
void
Sema::AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl,
CXXRecordDecl *ActingContext, QualType ObjectType,
Expr::Classification ObjectClassification,
ArrayRef<Expr *> Args,
OverloadCandidateSet &CandidateSet,
bool SuppressUserConversions,
bool PartialOverloading,
ConversionSequenceList EarlyConversions,
OverloadCandidateParamOrder PO) {
const FunctionProtoType *Proto
= dyn_cast<FunctionProtoType>(Method->getType()->getAs<FunctionType>());
assert(Proto && "Methods without a prototype cannot be overloaded");
assert(!isa<CXXConstructorDecl>(Method) &&
"Use AddOverloadCandidate for constructors");
if (!CandidateSet.isNewCandidate(Method, PO))
return;
// C++11 [class.copy]p23: [DR1402]
// A defaulted move assignment operator that is defined as deleted is
// ignored by overload resolution.
if (Method->isDefaulted() && Method->isDeleted() &&
Method->isMoveAssignmentOperator())
return;
// Overload resolution is always an unevaluated context.
EnterExpressionEvaluationContext Unevaluated(
*this, Sema::ExpressionEvaluationContext::Unevaluated);
// Add this candidate
OverloadCandidate &Candidate =
CandidateSet.addCandidate(Args.size() + 1, EarlyConversions);
Candidate.FoundDecl = FoundDecl;
Candidate.Function = Method;
Candidate.RewriteKind =
CandidateSet.getRewriteInfo().getRewriteKind(Method, PO);
Candidate.IsSurrogate = false;
Candidate.IgnoreObjectArgument = false;
Candidate.ExplicitCallArguments = Args.size();
unsigned NumParams = Proto->getNumParams();
// (C++ 13.3.2p2): A candidate function having fewer than m
// parameters is viable only if it has an ellipsis in its parameter
// list (8.3.5).
if (TooManyArguments(NumParams, Args.size(), PartialOverloading) &&
!Proto->isVariadic()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_too_many_arguments;
return;
}
// (C++ 13.3.2p2): A candidate function having more than m parameters
// is viable only if the (m+1)st parameter has a default argument
// (8.3.6). For the purposes of overload resolution, the
// parameter list is truncated on the right, so that there are
// exactly m parameters.
unsigned MinRequiredArgs = Method->getMinRequiredArguments();
if (Args.size() < MinRequiredArgs && !PartialOverloading) {
// Not enough arguments.
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_too_few_arguments;
return;
}
Candidate.Viable = true;
if (Method->isStatic() || ObjectType.isNull())
// The implicit object argument is ignored.
Candidate.IgnoreObjectArgument = true;
else {
unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed ? 1 : 0;
// Determine the implicit conversion sequence for the object
// parameter.
Candidate.Conversions[ConvIdx] = TryObjectArgumentInitialization(
*this, CandidateSet.getLocation(), ObjectType, ObjectClassification,
Method, ActingContext);
if (Candidate.Conversions[ConvIdx].isBad()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_bad_conversion;
return;
}
}
// (CUDA B.1): Check for invalid calls between targets.
if (getLangOpts().CUDA)
if (const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext))
if (!IsAllowedCUDACall(Caller, Method)) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_bad_target;
return;
}
if (Method->getTrailingRequiresClause()) {
ConstraintSatisfaction Satisfaction;
if (CheckFunctionConstraints(Method, Satisfaction) ||
!Satisfaction.IsSatisfied) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_constraints_not_satisfied;
return;
}
}
// Determine the implicit conversion sequences for each of the
// arguments.
for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) {
unsigned ConvIdx =
PO == OverloadCandidateParamOrder::Reversed ? 0 : (ArgIdx + 1);
if (Candidate.Conversions[ConvIdx].isInitialized()) {
// We already formed a conversion sequence for this parameter during
// template argument deduction.
} else if (ArgIdx < NumParams) {
// (C++ 13.3.2p3): for F to be a viable function, there shall
// exist for each argument an implicit conversion sequence
// (13.3.3.1) that converts that argument to the corresponding
// parameter of F.
QualType ParamType = Proto->getParamType(ArgIdx);
Candidate.Conversions[ConvIdx]
= TryCopyInitialization(*this, Args[ArgIdx], ParamType,
SuppressUserConversions,
/*InOverloadResolution=*/true,
/*AllowObjCWritebackConversion=*/
getLangOpts().ObjCAutoRefCount);
if (Candidate.Conversions[ConvIdx].isBad()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_bad_conversion;
return;
}
} else {
// (C++ 13.3.2p2): For the purposes of overload resolution, any
// argument for which there is no corresponding parameter is
// considered to "match the ellipsis" (C+ 13.3.3.1.3).
Candidate.Conversions[ConvIdx].setEllipsis();
}
}
if (EnableIfAttr *FailedAttr =
CheckEnableIf(Method, CandidateSet.getLocation(), Args, true)) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_enable_if;
Candidate.DeductionFailure.Data = FailedAttr;
return;
}
if (Method->isMultiVersion() && Method->hasAttr<TargetAttr>() &&
!Method->getAttr<TargetAttr>()->isDefaultVersion()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_non_default_multiversion_function;
}
}
/// Add a C++ member function template as a candidate to the candidate
/// set, using template argument deduction to produce an appropriate member
/// function template specialization.
void Sema::AddMethodTemplateCandidate(
FunctionTemplateDecl *MethodTmpl, DeclAccessPair FoundDecl,
CXXRecordDecl *ActingContext,
TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ObjectType,
Expr::Classification ObjectClassification, ArrayRef<Expr *> Args,
OverloadCandidateSet &CandidateSet, bool SuppressUserConversions,
bool PartialOverloading, OverloadCandidateParamOrder PO) {
if (!CandidateSet.isNewCandidate(MethodTmpl, PO))
return;
// C++ [over.match.funcs]p7:
// In each case where a candidate is a function template, candidate
// function template specializations are generated using template argument
// deduction (14.8.3, 14.8.2). Those candidates are then handled as
// candidate functions in the usual way.113) A given name can refer to one
// or more function templates and also to a set of overloaded non-template
// functions. In such a case, the candidate functions generated from each
// function template are combined with the set of non-template candidate
// functions.
TemplateDeductionInfo Info(CandidateSet.getLocation());
FunctionDecl *Specialization = nullptr;
ConversionSequenceList Conversions;
if (TemplateDeductionResult Result = DeduceTemplateArguments(
MethodTmpl, ExplicitTemplateArgs, Args, Specialization, Info,
PartialOverloading, [&](ArrayRef<QualType> ParamTypes) {
return CheckNonDependentConversions(
MethodTmpl, ParamTypes, Args, CandidateSet, Conversions,
SuppressUserConversions, ActingContext, ObjectType,
ObjectClassification, PO);
})) {
OverloadCandidate &Candidate =
CandidateSet.addCandidate(Conversions.size(), Conversions);
Candidate.FoundDecl = FoundDecl;
Candidate.Function = MethodTmpl->getTemplatedDecl();
Candidate.Viable = false;
Candidate.RewriteKind =
CandidateSet.getRewriteInfo().getRewriteKind(Candidate.Function, PO);
Candidate.IsSurrogate = false;
Candidate.IgnoreObjectArgument =
cast<CXXMethodDecl>(Candidate.Function)->isStatic() ||
ObjectType.isNull();
Candidate.ExplicitCallArguments = Args.size();
if (Result == TDK_NonDependentConversionFailure)
Candidate.FailureKind = ovl_fail_bad_conversion;
else {
Candidate.FailureKind = ovl_fail_bad_deduction;
Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
Info);
}
return;
}
// Add the function template specialization produced by template argument
// deduction as a candidate.
assert(Specialization && "Missing member function template specialization?");
assert(isa<CXXMethodDecl>(Specialization) &&
"Specialization is not a member function?");
AddMethodCandidate(cast<CXXMethodDecl>(Specialization), FoundDecl,
ActingContext, ObjectType, ObjectClassification, Args,
CandidateSet, SuppressUserConversions, PartialOverloading,
Conversions, PO);
}
/// Determine whether a given function template has a simple explicit specifier
/// or a non-value-dependent explicit-specification that evaluates to true.
static bool isNonDependentlyExplicit(FunctionTemplateDecl *FTD) {
return ExplicitSpecifier::getFromDecl(FTD->getTemplatedDecl()).isExplicit();
}
/// Add a C++ function template specialization as a candidate
/// in the candidate set, using template argument deduction to produce
/// an appropriate function template specialization.
void Sema::AddTemplateOverloadCandidate(
FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
OverloadCandidateSet &CandidateSet, bool SuppressUserConversions,
bool PartialOverloading, bool AllowExplicit, ADLCallKind IsADLCandidate,
OverloadCandidateParamOrder PO) {
if (!CandidateSet.isNewCandidate(FunctionTemplate, PO))
return;
// If the function template has a non-dependent explicit specification,
// exclude it now if appropriate; we are not permitted to perform deduction
// and substitution in this case.
if (!AllowExplicit && isNonDependentlyExplicit(FunctionTemplate)) {
OverloadCandidate &Candidate = CandidateSet.addCandidate();
Candidate.FoundDecl = FoundDecl;
Candidate.Function = FunctionTemplate->getTemplatedDecl();
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_explicit;
return;
}
// C++ [over.match.funcs]p7:
// In each case where a candidate is a function template, candidate
// function template specializations are generated using template argument
// deduction (14.8.3, 14.8.2). Those candidates are then handled as
// candidate functions in the usual way.113) A given name can refer to one
// or more function templates and also to a set of overloaded non-template
// functions. In such a case, the candidate functions generated from each
// function template are combined with the set of non-template candidate
// functions.
TemplateDeductionInfo Info(CandidateSet.getLocation());
FunctionDecl *Specialization = nullptr;
ConversionSequenceList Conversions;
if (TemplateDeductionResult Result = DeduceTemplateArguments(
FunctionTemplate, ExplicitTemplateArgs, Args, Specialization, Info,
PartialOverloading, [&](ArrayRef<QualType> ParamTypes) {
return CheckNonDependentConversions(
FunctionTemplate, ParamTypes, Args, CandidateSet, Conversions,
SuppressUserConversions, nullptr, QualType(), {}, PO);
})) {
OverloadCandidate &Candidate =
CandidateSet.addCandidate(Conversions.size(), Conversions);
Candidate.FoundDecl = FoundDecl;
Candidate.Function = FunctionTemplate->getTemplatedDecl();
Candidate.Viable = false;
Candidate.RewriteKind =
CandidateSet.getRewriteInfo().getRewriteKind(Candidate.Function, PO);
Candidate.IsSurrogate = false;
Candidate.IsADLCandidate = IsADLCandidate;
// Ignore the object argument if there is one, since we don't have an object
// type.
Candidate.IgnoreObjectArgument =
isa<CXXMethodDecl>(Candidate.Function) &&
!isa<CXXConstructorDecl>(Candidate.Function);
Candidate.ExplicitCallArguments = Args.size();
if (Result == TDK_NonDependentConversionFailure)
Candidate.FailureKind = ovl_fail_bad_conversion;
else {
Candidate.FailureKind = ovl_fail_bad_deduction;
Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
Info);
}
return;
}
// Add the function template specialization produced by template argument
// deduction as a candidate.
assert(Specialization && "Missing function template specialization?");
AddOverloadCandidate(
Specialization, FoundDecl, Args, CandidateSet, SuppressUserConversions,
PartialOverloading, AllowExplicit,
/*AllowExplicitConversions*/ false, IsADLCandidate, Conversions, PO);
}
/// Check that implicit conversion sequences can be formed for each argument
/// whose corresponding parameter has a non-dependent type, per DR1391's
/// [temp.deduct.call]p10.
bool Sema::CheckNonDependentConversions(
FunctionTemplateDecl *FunctionTemplate, ArrayRef<QualType> ParamTypes,
ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet,
ConversionSequenceList &Conversions, bool SuppressUserConversions,
CXXRecordDecl *ActingContext, QualType ObjectType,
Expr::Classification ObjectClassification, OverloadCandidateParamOrder PO) {
// FIXME: The cases in which we allow explicit conversions for constructor
// arguments never consider calling a constructor template. It's not clear
// that is correct.
const bool AllowExplicit = false;
auto *FD = FunctionTemplate->getTemplatedDecl();
auto *Method = dyn_cast<CXXMethodDecl>(FD);
bool HasThisConversion = Method && !isa<CXXConstructorDecl>(Method);
unsigned ThisConversions = HasThisConversion ? 1 : 0;
Conversions =
CandidateSet.allocateConversionSequences(ThisConversions + Args.size());
// Overload resolution is always an unevaluated context.
EnterExpressionEvaluationContext Unevaluated(
*this, Sema::ExpressionEvaluationContext::Unevaluated);
// For a method call, check the 'this' conversion here too. DR1391 doesn't
// require that, but this check should never result in a hard error, and
// overload resolution is permitted to sidestep instantiations.
if (HasThisConversion && !cast<CXXMethodDecl>(FD)->isStatic() &&
!ObjectType.isNull()) {
unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed ? 1 : 0;
Conversions[ConvIdx] = TryObjectArgumentInitialization(
*this, CandidateSet.getLocation(), ObjectType, ObjectClassification,
Method, ActingContext);
if (Conversions[ConvIdx].isBad())
return true;
}
for (unsigned I = 0, N = std::min(ParamTypes.size(), Args.size()); I != N;
++I) {
QualType ParamType = ParamTypes[I];
if (!ParamType->isDependentType()) {
unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed
? 0
: (ThisConversions + I);
Conversions[ConvIdx]
= TryCopyInitialization(*this, Args[I], ParamType,
SuppressUserConversions,
/*InOverloadResolution=*/true,
/*AllowObjCWritebackConversion=*/
getLangOpts().ObjCAutoRefCount,
AllowExplicit);
if (Conversions[ConvIdx].isBad())
return true;
}
}
return false;
}
/// Determine whether this is an allowable conversion from the result
/// of an explicit conversion operator to the expected type, per C++
/// [over.match.conv]p1 and [over.match.ref]p1.
///
/// \param ConvType The return type of the conversion function.
///
/// \param ToType The type we are converting to.
///
/// \param AllowObjCPointerConversion Allow a conversion from one
/// Objective-C pointer to another.
///
/// \returns true if the conversion is allowable, false otherwise.
static bool isAllowableExplicitConversion(Sema &S,
QualType ConvType, QualType ToType,
bool AllowObjCPointerConversion) {
QualType ToNonRefType = ToType.getNonReferenceType();
// Easy case: the types are the same.
if (S.Context.hasSameUnqualifiedType(ConvType, ToNonRefType))
return true;
// Allow qualification conversions.
bool ObjCLifetimeConversion;
if (S.IsQualificationConversion(ConvType, ToNonRefType, /*CStyle*/false,
ObjCLifetimeConversion))
return true;
// If we're not allowed to consider Objective-C pointer conversions,
// we're done.
if (!AllowObjCPointerConversion)
return false;
// Is this an Objective-C pointer conversion?
bool IncompatibleObjC = false;
QualType ConvertedType;
return S.isObjCPointerConversion(ConvType, ToNonRefType, ConvertedType,
IncompatibleObjC);
}
/// AddConversionCandidate - Add a C++ conversion function as a
/// candidate in the candidate set (C++ [over.match.conv],
/// C++ [over.match.copy]). From is the expression we're converting from,
/// and ToType is the type that we're eventually trying to convert to
/// (which may or may not be the same type as the type that the
/// conversion function produces).
void Sema::AddConversionCandidate(
CXXConversionDecl *Conversion, DeclAccessPair FoundDecl,
CXXRecordDecl *ActingContext, Expr *From, QualType ToType,
OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
bool AllowExplicit, bool AllowResultConversion) {
assert(!Conversion->getDescribedFunctionTemplate() &&
"Conversion function templates use AddTemplateConversionCandidate");
QualType ConvType = Conversion->getConversionType().getNonReferenceType();
if (!CandidateSet.isNewCandidate(Conversion))
return;
// If the conversion function has an undeduced return type, trigger its
// deduction now.
if (getLangOpts().CPlusPlus14 && ConvType->isUndeducedType()) {
if (DeduceReturnType(Conversion, From->getExprLoc()))
return;
ConvType = Conversion->getConversionType().getNonReferenceType();
}
// If we don't allow any conversion of the result type, ignore conversion
// functions that don't convert to exactly (possibly cv-qualified) T.
if (!AllowResultConversion &&
!Context.hasSameUnqualifiedType(Conversion->getConversionType(), ToType))
return;
// Per C++ [over.match.conv]p1, [over.match.ref]p1, an explicit conversion
// operator is only a candidate if its return type is the target type or
// can be converted to the target type with a qualification conversion.
//
// FIXME: Include such functions in the candidate list and explain why we
// can't select them.
if (Conversion->isExplicit() &&
!isAllowableExplicitConversion(*this, ConvType, ToType,
AllowObjCConversionOnExplicit))
return;
// Overload resolution is always an unevaluated context.
EnterExpressionEvaluationContext Unevaluated(
*this, Sema::ExpressionEvaluationContext::Unevaluated);
// Add this candidate
OverloadCandidate &Candidate = CandidateSet.addCandidate(1);
Candidate.FoundDecl = FoundDecl;
Candidate.Function = Conversion;
Candidate.IsSurrogate = false;
Candidate.IgnoreObjectArgument = false;
Candidate.FinalConversion.setAsIdentityConversion();
Candidate.FinalConversion.setFromType(ConvType);
Candidate.FinalConversion.setAllToTypes(ToType);
Candidate.Viable = true;
Candidate.ExplicitCallArguments = 1;
// Explicit functions are not actually candidates at all if we're not
// allowing them in this context, but keep them around so we can point
// to them in diagnostics.
if (!AllowExplicit && Conversion->isExplicit()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_explicit;
return;
}
// C++ [over.match.funcs]p4:
// For conversion functions, the function is considered to be a member of
// the class of the implicit implied object argument for the purpose of
// defining the type of the implicit object parameter.
//
// Determine the implicit conversion sequence for the implicit
// object parameter.
QualType ImplicitParamType = From->getType();
if (const PointerType *FromPtrType = ImplicitParamType->getAs<PointerType>())
ImplicitParamType = FromPtrType->getPointeeType();
CXXRecordDecl *ConversionContext
= cast<CXXRecordDecl>(ImplicitParamType->castAs<RecordType>()->getDecl());
Candidate.Conversions[0] = TryObjectArgumentInitialization(
*this, CandidateSet.getLocation(), From->getType(),
From->Classify(Context), Conversion, ConversionContext);
if (Candidate.Conversions[0].isBad()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_bad_conversion;
return;
}
if (Conversion->getTrailingRequiresClause()) {
ConstraintSatisfaction Satisfaction;
if (CheckFunctionConstraints(Conversion, Satisfaction) ||
!Satisfaction.IsSatisfied) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_constraints_not_satisfied;
return;
}
}
// We won't go through a user-defined type conversion function to convert a
// derived to base as such conversions are given Conversion Rank. They only
// go through a copy constructor. 13.3.3.1.2-p4 [over.ics.user]
QualType FromCanon
= Context.getCanonicalType(From->getType().getUnqualifiedType());
QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType();
if (FromCanon == ToCanon ||
IsDerivedFrom(CandidateSet.getLocation(), FromCanon, ToCanon)) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_trivial_conversion;
return;
}
// To determine what the conversion from the result of calling the
// conversion function to the type we're eventually trying to
// convert to (ToType), we need to synthesize a call to the
// conversion function and attempt copy initialization from it. This
// makes sure that we get the right semantics with respect to
// lvalues/rvalues and the type. Fortunately, we can allocate this
// call on the stack and we don't need its arguments to be
// well-formed.
DeclRefExpr ConversionRef(Context, Conversion, false, Conversion->getType(),
VK_LValue, From->getBeginLoc());
ImplicitCastExpr ConversionFn(ImplicitCastExpr::OnStack,
Context.getPointerType(Conversion->getType()),
CK_FunctionToPointerDecay, &ConversionRef,
VK_PRValue, FPOptionsOverride());
QualType ConversionType = Conversion->getConversionType();
if (!isCompleteType(From->getBeginLoc(), ConversionType)) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_bad_final_conversion;
return;
}
ExprValueKind VK = Expr::getValueKindForType(ConversionType);
// Note that it is safe to allocate CallExpr on the stack here because
// there are 0 arguments (i.e., nothing is allocated using ASTContext's
// allocator).
QualType CallResultType = ConversionType.getNonLValueExprType(Context);
alignas(CallExpr) char Buffer[sizeof(CallExpr) + sizeof(Stmt *)];
CallExpr *TheTemporaryCall = CallExpr::CreateTemporary(
Buffer, &ConversionFn, CallResultType, VK, From->getBeginLoc());
ImplicitConversionSequence ICS =
TryCopyInitialization(*this, TheTemporaryCall, ToType,
/*SuppressUserConversions=*/true,
/*InOverloadResolution=*/false,
/*AllowObjCWritebackConversion=*/false);
switch (ICS.getKind()) {
case ImplicitConversionSequence::StandardConversion:
Candidate.FinalConversion = ICS.Standard;
// C++ [over.ics.user]p3:
// If the user-defined conversion is specified by a specialization of a
// conversion function template, the second standard conversion sequence
// shall have exact match rank.
if (Conversion->getPrimaryTemplate() &&
GetConversionRank(ICS.Standard.Second) != ICR_Exact_Match) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_final_conversion_not_exact;
return;
}
// C++0x [dcl.init.ref]p5:
// In the second case, if the reference is an rvalue reference and
// the second standard conversion sequence of the user-defined
// conversion sequence includes an lvalue-to-rvalue conversion, the
// program is ill-formed.
if (ToType->isRValueReferenceType() &&
ICS.Standard.First == ICK_Lvalue_To_Rvalue) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_bad_final_conversion;
return;
}
break;
case ImplicitConversionSequence::BadConversion:
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_bad_final_conversion;
return;
default:
llvm_unreachable(
"Can only end up with a standard conversion sequence or failure");
}
if (EnableIfAttr *FailedAttr =
CheckEnableIf(Conversion, CandidateSet.getLocation(), None)) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_enable_if;
Candidate.DeductionFailure.Data = FailedAttr;
return;
}
if (Conversion->isMultiVersion() && Conversion->hasAttr<TargetAttr>() &&
!Conversion->getAttr<TargetAttr>()->isDefaultVersion()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_non_default_multiversion_function;
}
}
/// Adds a conversion function template specialization
/// candidate to the overload set, using template argument deduction
/// to deduce the template arguments of the conversion function
/// template from the type that we are converting to (C++
/// [temp.deduct.conv]).
void Sema::AddTemplateConversionCandidate(
FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
CXXRecordDecl *ActingDC, Expr *From, QualType ToType,
OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
bool AllowExplicit, bool AllowResultConversion) {
assert(isa<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()) &&
"Only conversion function templates permitted here");
if (!CandidateSet.isNewCandidate(FunctionTemplate))
return;
// If the function template has a non-dependent explicit specification,
// exclude it now if appropriate; we are not permitted to perform deduction
// and substitution in this case.
if (!AllowExplicit && isNonDependentlyExplicit(FunctionTemplate)) {
OverloadCandidate &Candidate = CandidateSet.addCandidate();
Candidate.FoundDecl = FoundDecl;
Candidate.Function = FunctionTemplate->getTemplatedDecl();
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_explicit;
return;
}
TemplateDeductionInfo Info(CandidateSet.getLocation());
CXXConversionDecl *Specialization = nullptr;
if (TemplateDeductionResult Result
= DeduceTemplateArguments(FunctionTemplate, ToType,
Specialization, Info)) {
OverloadCandidate &Candidate = CandidateSet.addCandidate();
Candidate.FoundDecl = FoundDecl;
Candidate.Function = FunctionTemplate->getTemplatedDecl();
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_bad_deduction;
Candidate.IsSurrogate = false;
Candidate.IgnoreObjectArgument = false;
Candidate.ExplicitCallArguments = 1;
Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
Info);
return;
}
// Add the conversion function template specialization produced by
// template argument deduction as a candidate.
assert(Specialization && "Missing function template specialization?");
AddConversionCandidate(Specialization, FoundDecl, ActingDC, From, ToType,
CandidateSet, AllowObjCConversionOnExplicit,
AllowExplicit, AllowResultConversion);
}
/// AddSurrogateCandidate - Adds a "surrogate" candidate function that
/// converts the given @c Object to a function pointer via the
/// conversion function @c Conversion, and then attempts to call it
/// with the given arguments (C++ [over.call.object]p2-4). Proto is
/// the type of function that we'll eventually be calling.
void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion,
DeclAccessPair FoundDecl,
CXXRecordDecl *ActingContext,
const FunctionProtoType *Proto,
Expr *Object,
ArrayRef<Expr *> Args,
OverloadCandidateSet& CandidateSet) {
if (!CandidateSet.isNewCandidate(Conversion))
return;
// Overload resolution is always an unevaluated context.
EnterExpressionEvaluationContext Unevaluated(
*this, Sema::ExpressionEvaluationContext::Unevaluated);
OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size() + 1);
Candidate.FoundDecl = FoundDecl;
Candidate.Function = nullptr;
Candidate.Surrogate = Conversion;
Candidate.Viable = true;
Candidate.IsSurrogate = true;
Candidate.IgnoreObjectArgument = false;
Candidate.ExplicitCallArguments = Args.size();
// Determine the implicit conversion sequence for the implicit
// object parameter.
ImplicitConversionSequence ObjectInit = TryObjectArgumentInitialization(
*this, CandidateSet.getLocation(), Object->getType(),
Object->Classify(Context), Conversion, ActingContext);
if (ObjectInit.isBad()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_bad_conversion;
Candidate.Conversions[0] = ObjectInit;
return;
}
// The first conversion is actually a user-defined conversion whose
// first conversion is ObjectInit's standard conversion (which is
// effectively a reference binding). Record it as such.
Candidate.Conversions[0].setUserDefined();
Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard;
Candidate.Conversions[0].UserDefined.EllipsisConversion = false;
Candidate.Conversions[0].UserDefined.HadMultipleCandidates = false;
Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion;
Candidate.Conversions[0].UserDefined.FoundConversionFunction = FoundDecl;
Candidate.Conversions[0].UserDefined.After
= Candidate.Conversions[0].UserDefined.Before;
Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion();
// Find the
unsigned NumParams = Proto->getNumParams();
// (C++ 13.3.2p2): A candidate function having fewer than m
// parameters is viable only if it has an ellipsis in its parameter
// list (8.3.5).
if (Args.size() > NumParams && !Proto->isVariadic()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_too_many_arguments;
return;
}
// Function types don't have any default arguments, so just check if
// we have enough arguments.
if (Args.size() < NumParams) {
// Not enough arguments.
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_too_few_arguments;
return;
}
// Determine the implicit conversion sequences for each of the
// arguments.
for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
if (ArgIdx < NumParams) {
// (C++ 13.3.2p3): for F to be a viable function, there shall
// exist for each argument an implicit conversion sequence
// (13.3.3.1) that converts that argument to the corresponding
// parameter of F.
QualType ParamType = Proto->getParamType(ArgIdx);
Candidate.Conversions[ArgIdx + 1]
= TryCopyInitialization(*this, Args[ArgIdx], ParamType,
/*SuppressUserConversions=*/false,
/*InOverloadResolution=*/false,
/*AllowObjCWritebackConversion=*/
getLangOpts().ObjCAutoRefCount);
if (Candidate.Conversions[ArgIdx + 1].isBad()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_bad_conversion;
return;
}
} else {
// (C++ 13.3.2p2): For the purposes of overload resolution, any
// argument for which there is no corresponding parameter is
// considered to ""match the ellipsis" (C+ 13.3.3.1.3).
Candidate.Conversions[ArgIdx + 1].setEllipsis();
}
}
if (EnableIfAttr *FailedAttr =
CheckEnableIf(Conversion, CandidateSet.getLocation(), None)) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_enable_if;
Candidate.DeductionFailure.Data = FailedAttr;
return;
}
}
/// Add all of the non-member operator function declarations in the given
/// function set to the overload candidate set.
void Sema::AddNonMemberOperatorCandidates(
const UnresolvedSetImpl &Fns, ArrayRef<Expr *> Args,
OverloadCandidateSet &CandidateSet,
TemplateArgumentListInfo *ExplicitTemplateArgs) {
for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) {
NamedDecl *D = F.getDecl()->getUnderlyingDecl();
ArrayRef<Expr *> FunctionArgs = Args;
FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D);
FunctionDecl *FD =
FunTmpl ? FunTmpl->getTemplatedDecl() : cast<FunctionDecl>(D);
// Don't consider rewritten functions if we're not rewriting.
if (!CandidateSet.getRewriteInfo().isAcceptableCandidate(FD))
continue;
assert(!isa<CXXMethodDecl>(FD) &&
"unqualified operator lookup found a member function");
if (FunTmpl) {
AddTemplateOverloadCandidate(FunTmpl, F.getPair(), ExplicitTemplateArgs,
FunctionArgs, CandidateSet);
if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD))
AddTemplateOverloadCandidate(
FunTmpl, F.getPair(), ExplicitTemplateArgs,
{FunctionArgs[1], FunctionArgs[0]}, CandidateSet, false, false,
true, ADLCallKind::NotADL, OverloadCandidateParamOrder::Reversed);
} else {
if (ExplicitTemplateArgs)
continue;
AddOverloadCandidate(FD, F.getPair(), FunctionArgs, CandidateSet);
if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD))
AddOverloadCandidate(FD, F.getPair(),
{FunctionArgs[1], FunctionArgs[0]}, CandidateSet,
false, false, true, false, ADLCallKind::NotADL,
None, OverloadCandidateParamOrder::Reversed);
}
}
}
/// Add overload candidates for overloaded operators that are
/// member functions.
///
/// Add the overloaded operator candidates that are member functions
/// for the operator Op that was used in an operator expression such
/// as "x Op y". , Args/NumArgs provides the operator arguments, and
/// CandidateSet will store the added overload candidates. (C++
/// [over.match.oper]).
void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op,
SourceLocation OpLoc,
ArrayRef<Expr *> Args,
OverloadCandidateSet &CandidateSet,
OverloadCandidateParamOrder PO) {
DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
// C++ [over.match.oper]p3:
// For a unary operator @ with an operand of a type whose
// cv-unqualified version is T1, and for a binary operator @ with
// a left operand of a type whose cv-unqualified version is T1 and
// a right operand of a type whose cv-unqualified version is T2,
// three sets of candidate functions, designated member
// candidates, non-member candidates and built-in candidates, are
// constructed as follows:
QualType T1 = Args[0]->getType();
// -- If T1 is a complete class type or a class currently being
// defined, the set of member candidates is the result of the
// qualified lookup of T1::operator@ (13.3.1.1.1); otherwise,
// the set of member candidates is empty.
if (const RecordType *T1Rec = T1->getAs<RecordType>()) {
// Complete the type if it can be completed.
if (!isCompleteType(OpLoc, T1) && !T1Rec->isBeingDefined())
return;
// If the type is neither complete nor being defined, bail out now.
if (!T1Rec->getDecl()->getDefinition())
return;
LookupResult Operators(*this, OpName, OpLoc, LookupOrdinaryName);
LookupQualifiedName(Operators, T1Rec->getDecl());
Operators.suppressDiagnostics();
for (LookupResult::iterator Oper = Operators.begin(),
OperEnd = Operators.end();
Oper != OperEnd;
++Oper)
AddMethodCandidate(Oper.getPair(), Args[0]->getType(),
Args[0]->Classify(Context), Args.slice(1),
CandidateSet, /*SuppressUserConversion=*/false, PO);
}
}
/// AddBuiltinCandidate - Add a candidate for a built-in
/// operator. ResultTy and ParamTys are the result and parameter types
/// of the built-in candidate, respectively. Args and NumArgs are the
/// arguments being passed to the candidate. IsAssignmentOperator
/// should be true when this built-in candidate is an assignment
/// operator. NumContextualBoolArguments is the number of arguments
/// (at the beginning of the argument list) that will be contextually
/// converted to bool.
void Sema::AddBuiltinCandidate(QualType *ParamTys, ArrayRef<Expr *> Args,
OverloadCandidateSet& CandidateSet,
bool IsAssignmentOperator,
unsigned NumContextualBoolArguments) {
// Overload resolution is always an unevaluated context.
EnterExpressionEvaluationContext Unevaluated(
*this, Sema::ExpressionEvaluationContext::Unevaluated);
// Add this candidate
OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size());
Candidate.FoundDecl = DeclAccessPair::make(nullptr, AS_none);
Candidate.Function = nullptr;
Candidate.IsSurrogate = false;
Candidate.IgnoreObjectArgument = false;
std::copy(ParamTys, ParamTys + Args.size(), Candidate.BuiltinParamTypes);
// Determine the implicit conversion sequences for each of the
// arguments.
Candidate.Viable = true;
Candidate.ExplicitCallArguments = Args.size();
for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
// C++ [over.match.oper]p4:
// For the built-in assignment operators, conversions of the
// left operand are restricted as follows:
// -- no temporaries are introduced to hold the left operand, and
// -- no user-defined conversions are applied to the left
// operand to achieve a type match with the left-most
// parameter of a built-in candidate.
//
// We block these conversions by turning off user-defined
// conversions, since that is the only way that initialization of
// a reference to a non-class type can occur from something that
// is not of the same type.
if (ArgIdx < NumContextualBoolArguments) {
assert(ParamTys[ArgIdx] == Context.BoolTy &&
"Contextual conversion to bool requires bool type");
Candidate.Conversions[ArgIdx]
= TryContextuallyConvertToBool(*this, Args[ArgIdx]);
} else {
Candidate.Conversions[ArgIdx]
= TryCopyInitialization(*this, Args[ArgIdx], ParamTys[ArgIdx],
ArgIdx == 0 && IsAssignmentOperator,
/*InOverloadResolution=*/false,
/*AllowObjCWritebackConversion=*/
getLangOpts().ObjCAutoRefCount);
}
if (Candidate.Conversions[ArgIdx].isBad()) {
Candidate.Viable = false;
Candidate.FailureKind = ovl_fail_bad_conversion;
break;
}
}
}
namespace {
/// BuiltinCandidateTypeSet - A set of types that will be used for the
/// candidate operator functions for built-in operators (C++
/// [over.built]). The types are separated into pointer types and
/// enumeration types.
class BuiltinCandidateTypeSet {
/// TypeSet - A set of types.
typedef llvm::SetVector<QualType, SmallVector<QualType, 8>,
llvm::SmallPtrSet<QualType, 8>> TypeSet;
/// PointerTypes - The set of pointer types that will be used in the
/// built-in candidates.
TypeSet PointerTypes;
/// MemberPointerTypes - The set of member pointer types that will be
/// used in the built-in candidates.
TypeSet MemberPointerTypes;
/// EnumerationTypes - The set of enumeration types that will be
/// used in the built-in candidates.
TypeSet EnumerationTypes;
/// The set of vector types that will be used in the built-in
/// candidates.
TypeSet VectorTypes;
/// The set of matrix types that will be used in the built-in
/// candidates.
TypeSet MatrixTypes;
/// A flag indicating non-record types are viable candidates
bool HasNonRecordTypes;
/// A flag indicating whether either arithmetic or enumeration types
/// were present in the candidate set.
bool HasArithmeticOrEnumeralTypes;
/// A flag indicating whether the nullptr type was present in the
/// candidate set.
bool HasNullPtrType;
/// Sema - The semantic analysis instance where we are building the
/// candidate type set.
Sema &SemaRef;
/// Context - The AST context in which we will build the type sets.
ASTContext &Context;
bool AddPointerWithMoreQualifiedTypeVariants(QualType Ty,
const Qualifiers &VisibleQuals);
bool AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty);
public:
/// iterator - Iterates through the types that are part of the set.
typedef TypeSet::iterator iterator;
BuiltinCandidateTypeSet(Sema &SemaRef)
: HasNonRecordTypes(false),
HasArithmeticOrEnumeralTypes(false),
HasNullPtrType(false),
SemaRef(SemaRef),
Context(SemaRef.Context) { }
void AddTypesConvertedFrom(QualType Ty,
SourceLocation Loc,
bool AllowUserConversions,
bool AllowExplicitConversions,
const Qualifiers &VisibleTypeConversionsQuals);
llvm::iterator_range<iterator> pointer_types() { return PointerTypes; }
llvm::iterator_range<iterator> member_pointer_types() {
return MemberPointerTypes;
}
llvm::iterator_range<iterator> enumeration_types() {
return EnumerationTypes;
}
llvm::iterator_range<iterator> vector_types() { return VectorTypes; }
llvm::iterator_range<iterator> matrix_types() { return MatrixTypes; }
bool containsMatrixType(QualType Ty) const { return MatrixTypes.count(Ty); }
bool hasNonRecordTypes() { return HasNonRecordTypes; }
bool hasArithmeticOrEnumeralTypes() { return HasArithmeticOrEnumeralTypes; }
bool hasNullPtrType() const { return HasNullPtrType; }
};
} // end anonymous namespace
/// AddPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to
/// the set of pointer types along with any more-qualified variants of
/// that type. For example, if @p Ty is "int const *", this routine
/// will add "int const *", "int const volatile *", "int const
/// restrict *", and "int const volatile restrict *" to the set of
/// pointer types. Returns true if the add of @p Ty itself succeeded,
/// false otherwise.
///
/// FIXME: what to do about extended qualifiers?
bool
BuiltinCandidateTypeSet::AddPointerWithMoreQualifiedTypeVariants(QualType Ty,
const Qualifiers &VisibleQuals) {
// Insert this type.
if (!PointerTypes.insert(Ty))
return false;
QualType PointeeTy;
const PointerType *PointerTy = Ty->getAs<PointerType>();
bool buildObjCPtr = false;
if (!PointerTy) {
const ObjCObjectPointerType *PTy = Ty->castAs<ObjCObjectPointerType>();
PointeeTy = PTy->getPointeeType();
buildObjCPtr = true;
} else {
PointeeTy = PointerTy->getPointeeType();
}
// Don't add qualified variants of arrays. For one, they're not allowed
// (the qualifier would sink to the element type), and for another, the
// only overload situation where it matters is subscript or pointer +- int,
// and those shouldn't have qualifier variants anyway.
if (PointeeTy->isArrayType())
return true;
unsigned BaseCVR = PointeeTy.getCVRQualifiers();
bool hasVolatile = VisibleQuals.hasVolatile();
bool hasRestrict = VisibleQuals.hasRestrict();
// Iterate through all strict supersets of BaseCVR.
for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) {
if ((CVR | BaseCVR) != CVR) continue;
// Skip over volatile if no volatile found anywhere in the types.
if ((CVR & Qualifiers::Volatile) && !hasVolatile) continue;
// Skip over restrict if no restrict found anywhere in the types, or if
// the type cannot be restrict-qualified.
if ((CVR & Qualifiers::Restrict) &&
(!hasRestrict ||
(!(PointeeTy->isAnyPointerType() || PointeeTy->isReferenceType()))))
continue;
// Build qualified pointee type.
QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR);
// Build qualified pointer type.
QualType QPointerTy;
if (!buildObjCPtr)
QPointerTy = Context.getPointerType(QPointeeTy);
else
QPointerTy = Context.getObjCObjectPointerType(QPointeeTy);
// Insert qualified pointer type.
PointerTypes.insert(QPointerTy);
}
return true;
}
/// AddMemberPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty
/// to the set of pointer types along with any more-qualified variants of
/// that type. For example, if @p Ty is "int const *", this routine
/// will add "int const *", "int const volatile *", "int const
/// restrict *", and "int const volatile restrict *" to the set of
/// pointer types. Returns true if the add of @p Ty itself succeeded,
/// false otherwise.
///
/// FIXME: what to do about extended qualifiers?
bool
BuiltinCandidateTypeSet::AddMemberPointerWithMoreQualifiedTypeVariants(
QualType Ty) {
// Insert this type.
if (!MemberPointerTypes.insert(Ty))
return false;
const MemberPointerType *PointerTy = Ty->getAs<MemberPointerType>();
assert(PointerTy && "type was not a member pointer type!");
QualType PointeeTy = PointerTy->getPointeeType();
// Don't add qualified variants of arrays. For one, they're not allowed
// (the qualifier would sink to the element type), and for another, the
// only overload situation where it matters is subscript or pointer +- int,
// and those shouldn't have qualifier variants anyway.
if (PointeeTy->isArrayType())
return true;
const Type *ClassTy = PointerTy->getClass();
// Iterate through all strict supersets of the pointee type's CVR
// qualifiers.
unsigned BaseCVR = PointeeTy.getCVRQualifiers();
for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) {
if ((CVR | BaseCVR) != CVR) continue;
QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR);
MemberPointerTypes.insert(
Context.getMemberPointerType(QPointeeTy, ClassTy));
}
return true;
}
/// AddTypesConvertedFrom - Add each of the types to which the type @p
/// Ty can be implicit converted to the given set of @p Types. We're
/// primarily interested in pointer types and enumeration types. We also
/// take member pointer types, for the conditional operator.
/// AllowUserConversions is true if we should look at the conversion
/// functions of a class type, and AllowExplicitConversions if we
/// should also include the explicit conversion functions of a class
/// type.
void
BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty,
SourceLocation Loc,
bool AllowUserConversions,
bool AllowExplicitConversions,
const Qualifiers &VisibleQuals) {
// Only deal with canonical types.
Ty = Context.getCanonicalType(Ty);
// Look through reference types; they aren't part of the type of an
// expression for the purposes of conversions.
if (const ReferenceType *RefTy = Ty->getAs<ReferenceType>())
Ty = RefTy->getPointeeType();
// If we're dealing with an array type, decay to the pointer.
if (Ty->isArrayType())
Ty = SemaRef.Context.getArrayDecayedType(Ty);
// Otherwise, we don't care about qualifiers on the type.
Ty = Ty.getLocalUnqualifiedType();
// Flag if we ever add a non-record type.
const RecordType *TyRec = Ty->getAs<RecordType>();
HasNonRecordTypes = HasNonRecordTypes || !TyRec;
// Flag if we encounter an arithmetic type.
HasArithmeticOrEnumeralTypes =
HasArithmeticOrEnumeralTypes || Ty->isArithmeticType();
if (Ty->isObjCIdType() || Ty->isObjCClassType())
PointerTypes.insert(Ty);
else if (Ty->getAs<PointerType>() || Ty->getAs<ObjCObjectPointerType>()) {
// Insert our type, and its more-qualified variants, into the set
// of types.
if (!AddPointerWithMoreQualifiedTypeVariants(Ty, VisibleQuals))
return;
} else if (Ty->isMemberPointerType()) {
// Member pointers are far easier, since the pointee can't be converted.
if (!AddMemberPointerWithMoreQualifiedTypeVariants(Ty))
return;
} else if (Ty->isEnumeralType()) {
HasArithmeticOrEnumeralTypes = true;
EnumerationTypes.insert(Ty);
} else if (Ty->isVectorType()) {
// We treat vector types as arithmetic types in many contexts as an
// extension.
HasArithmeticOrEnumeralTypes = true;
VectorTypes.insert(Ty);
} else if (Ty->isMatrixType()) {
// Similar to vector types, we treat vector types as arithmetic types in
// many contexts as an extension.
HasArithmeticOrEnumeralTypes = true;
MatrixTypes.insert(Ty);
} else if (Ty->isNullPtrType()) {
HasNullPtrType = true;
} else if (AllowUserConversions && TyRec) {
// No conversion functions in incomplete types.
if (!SemaRef.isCompleteType(Loc, Ty))
return;
CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl());
for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) {
if (isa<UsingShadowDecl>(D))
D = cast<UsingShadowDecl>(D)->getTargetDecl();
// Skip conversion function templates; they don't tell us anything
// about which builtin types we can convert to.
if (isa<FunctionTemplateDecl>(D))
continue;
CXXConversionDecl *Conv = cast<CXXConversionDecl>(D);
if (AllowExplicitConversions || !Conv->isExplicit()) {
AddTypesConvertedFrom(Conv->getConversionType(), Loc, false, false,
VisibleQuals);
}
}
}
}
/// Helper function for adjusting address spaces for the pointer or reference
/// operands of builtin operators depending on the argument.
static QualType AdjustAddressSpaceForBuiltinOperandType(Sema &S, QualType T,
Expr *Arg) {
return S.Context.getAddrSpaceQualType(T, Arg->getType().getAddressSpace());
}
/// Helper function for AddBuiltinOperatorCandidates() that adds
/// the volatile- and non-volatile-qualified assignment operators for the
/// given type to the candidate set.
static void AddBuiltinAssignmentOperatorCandidates(Sema &S,
QualType T,
ArrayRef<Expr *> Args,
OverloadCandidateSet &CandidateSet) {
QualType ParamTypes[2];
// T& operator=(T&, T)
ParamTypes[0] = S.Context.getLValueReferenceType(
AdjustAddressSpaceForBuiltinOperandType(S, T, Args[0]));
ParamTypes[1] = T;
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/true);
if (!S.Context.getCanonicalType(T).isVolatileQualified()) {
// volatile T& operator=(volatile T&, T)
ParamTypes[0] = S.Context.getLValueReferenceType(
AdjustAddressSpaceForBuiltinOperandType(S, S.Context.getVolatileType(T),
Args[0]));
ParamTypes[1] = T;
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/true);
}
}
/// CollectVRQualifiers - This routine returns Volatile/Restrict qualifiers,
/// if any, found in visible type conversion functions found in ArgExpr's type.
static Qualifiers CollectVRQualifiers(ASTContext &Context, Expr* ArgExpr) {
Qualifiers VRQuals;
const RecordType *TyRec;
if (const MemberPointerType *RHSMPType =
ArgExpr->getType()->getAs<MemberPointerType>())
TyRec = RHSMPType->getClass()->getAs<RecordType>();
else
TyRec = ArgExpr->getType()->getAs<RecordType>();
if (!TyRec) {
// Just to be safe, assume the worst case.
VRQuals.addVolatile();
VRQuals.addRestrict();
return VRQuals;
}
CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl());
if (!ClassDecl->hasDefinition())
return VRQuals;
for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) {
if (isa<UsingShadowDecl>(D))
D = cast<UsingShadowDecl>(D)->getTargetDecl();
if (CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(D)) {
QualType CanTy = Context.getCanonicalType(Conv->getConversionType());
if (const ReferenceType *ResTypeRef = CanTy->getAs<ReferenceType>())
CanTy = ResTypeRef->getPointeeType();
// Need to go down the pointer/mempointer chain and add qualifiers
// as see them.
bool done = false;
while (!done) {
if (CanTy.isRestrictQualified())
VRQuals.addRestrict();
if (const PointerType *ResTypePtr = CanTy->getAs<PointerType>())
CanTy = ResTypePtr->getPointeeType();
else if (const MemberPointerType *ResTypeMPtr =
CanTy->getAs<MemberPointerType>())
CanTy = ResTypeMPtr->getPointeeType();
else
done = true;
if (CanTy.isVolatileQualified())
VRQuals.addVolatile();
if (VRQuals.hasRestrict() && VRQuals.hasVolatile())
return VRQuals;
}
}
}
return VRQuals;
}
namespace {
/// Helper class to manage the addition of builtin operator overload
/// candidates. It provides shared state and utility methods used throughout
/// the process, as well as a helper method to add each group of builtin
/// operator overloads from the standard to a candidate set.
class BuiltinOperatorOverloadBuilder {
// Common instance state available to all overload candidate addition methods.
Sema &S;
ArrayRef<Expr *> Args;
Qualifiers VisibleTypeConversionsQuals;
bool HasArithmeticOrEnumeralCandidateType;
SmallVectorImpl<BuiltinCandidateTypeSet> &CandidateTypes;
OverloadCandidateSet &CandidateSet;
static constexpr int ArithmeticTypesCap = 24;
SmallVector<CanQualType, ArithmeticTypesCap> ArithmeticTypes;
// Define some indices used to iterate over the arithmetic types in
// ArithmeticTypes. The "promoted arithmetic types" are the arithmetic
// types are that preserved by promotion (C++ [over.built]p2).
unsigned FirstIntegralType,
LastIntegralType;
unsigned FirstPromotedIntegralType,
LastPromotedIntegralType;
unsigned FirstPromotedArithmeticType,
LastPromotedArithmeticType;
unsigned NumArithmeticTypes;
void InitArithmeticTypes() {
// Start of promoted types.
FirstPromotedArithmeticType = 0;
ArithmeticTypes.push_back(S.Context.FloatTy);
ArithmeticTypes.push_back(S.Context.DoubleTy);
ArithmeticTypes.push_back(S.Context.LongDoubleTy);
if (S.Context.getTargetInfo().hasFloat128Type())
ArithmeticTypes.push_back(S.Context.Float128Ty);
if (S.Context.getTargetInfo().hasIbm128Type())
ArithmeticTypes.push_back(S.Context.Ibm128Ty);
// Start of integral types.
FirstIntegralType = ArithmeticTypes.size();
FirstPromotedIntegralType = ArithmeticTypes.size();
ArithmeticTypes.push_back(S.Context.IntTy);
ArithmeticTypes.push_back(S.Context.LongTy);
ArithmeticTypes.push_back(S.Context.LongLongTy);
if (S.Context.getTargetInfo().hasInt128Type() ||
(S.Context.getAuxTargetInfo() &&
S.Context.getAuxTargetInfo()->hasInt128Type()))
ArithmeticTypes.push_back(S.Context.Int128Ty);
ArithmeticTypes.push_back(S.Context.UnsignedIntTy);
ArithmeticTypes.push_back(S.Context.UnsignedLongTy);
ArithmeticTypes.push_back(S.Context.UnsignedLongLongTy);
if (S.Context.getTargetInfo().hasInt128Type() ||
(S.Context.getAuxTargetInfo() &&
S.Context.getAuxTargetInfo()->hasInt128Type()))
ArithmeticTypes.push_back(S.Context.UnsignedInt128Ty);
LastPromotedIntegralType = ArithmeticTypes.size();
LastPromotedArithmeticType = ArithmeticTypes.size();
// End of promoted types.
ArithmeticTypes.push_back(S.Context.BoolTy);
ArithmeticTypes.push_back(S.Context.CharTy);
ArithmeticTypes.push_back(S.Context.WCharTy);
if (S.Context.getLangOpts().Char8)
ArithmeticTypes.push_back(S.Context.Char8Ty);
ArithmeticTypes.push_back(S.Context.Char16Ty);
ArithmeticTypes.push_back(S.Context.Char32Ty);
ArithmeticTypes.push_back(S.Context.SignedCharTy);
ArithmeticTypes.push_back(S.Context.ShortTy);
ArithmeticTypes.push_back(S.Context.UnsignedCharTy);
ArithmeticTypes.push_back(S.Context.UnsignedShortTy);
LastIntegralType = ArithmeticTypes.size();
NumArithmeticTypes = ArithmeticTypes.size();
// End of integral types.
// FIXME: What about complex? What about half?
assert(ArithmeticTypes.size() <= ArithmeticTypesCap &&
"Enough inline storage for all arithmetic types.");
}
/// Helper method to factor out the common pattern of adding overloads
/// for '++' and '--' builtin operators.
void addPlusPlusMinusMinusStyleOverloads(QualType CandidateTy,
bool HasVolatile,
bool HasRestrict) {
QualType ParamTypes[2] = {
S.Context.getLValueReferenceType(CandidateTy),
S.Context.IntTy
};
// Non-volatile version.
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
// Use a heuristic to reduce number of builtin candidates in the set:
// add volatile version only if there are conversions to a volatile type.
if (HasVolatile) {
ParamTypes[0] =
S.Context.getLValueReferenceType(
S.Context.getVolatileType(CandidateTy));
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
// Add restrict version only if there are conversions to a restrict type
// and our candidate type is a non-restrict-qualified pointer.
if (HasRestrict && CandidateTy->isAnyPointerType() &&
!CandidateTy.isRestrictQualified()) {
ParamTypes[0]
= S.Context.getLValueReferenceType(
S.Context.getCVRQualifiedType(CandidateTy, Qualifiers::Restrict));
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
if (HasVolatile) {
ParamTypes[0]
= S.Context.getLValueReferenceType(
S.Context.getCVRQualifiedType(CandidateTy,
(Qualifiers::Volatile |
Qualifiers::Restrict)));
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
}
}
/// Helper to add an overload candidate for a binary builtin with types \p L
/// and \p R.
void AddCandidate(QualType L, QualType R) {
QualType LandR[2] = {L, R};
S.AddBuiltinCandidate(LandR, Args, CandidateSet);
}
public:
BuiltinOperatorOverloadBuilder(
Sema &S, ArrayRef<Expr *> Args,
Qualifiers VisibleTypeConversionsQuals,
bool HasArithmeticOrEnumeralCandidateType,
SmallVectorImpl<BuiltinCandidateTypeSet> &CandidateTypes,
OverloadCandidateSet &CandidateSet)
: S(S), Args(Args),
VisibleTypeConversionsQuals(VisibleTypeConversionsQuals),
HasArithmeticOrEnumeralCandidateType(
HasArithmeticOrEnumeralCandidateType),
CandidateTypes(CandidateTypes),
CandidateSet(CandidateSet) {
InitArithmeticTypes();
}
// Increment is deprecated for bool since C++17.
//
// C++ [over.built]p3:
//
// For every pair (T, VQ), where T is an arithmetic type other
// than bool, and VQ is either volatile or empty, there exist
// candidate operator functions of the form
//
// VQ T& operator++(VQ T&);
// T operator++(VQ T&, int);
//
// C++ [over.built]p4:
//
// For every pair (T, VQ), where T is an arithmetic type other
// than bool, and VQ is either volatile or empty, there exist
// candidate operator functions of the form
//
// VQ T& operator--(VQ T&);
// T operator--(VQ T&, int);
void addPlusPlusMinusMinusArithmeticOverloads(OverloadedOperatorKind Op) {
if (!HasArithmeticOrEnumeralCandidateType)
return;
for (unsigned Arith = 0; Arith < NumArithmeticTypes; ++Arith) {
const auto TypeOfT = ArithmeticTypes[Arith];
if (TypeOfT == S.Context.BoolTy) {
if (Op == OO_MinusMinus)
continue;
if (Op == OO_PlusPlus && S.getLangOpts().CPlusPlus17)
continue;
}
addPlusPlusMinusMinusStyleOverloads(
TypeOfT,
VisibleTypeConversionsQuals.hasVolatile(),
VisibleTypeConversionsQuals.hasRestrict());
}
}
// C++ [over.built]p5:
//
// For every pair (T, VQ), where T is a cv-qualified or
// cv-unqualified object type, and VQ is either volatile or
// empty, there exist candidate operator functions of the form
//
// T*VQ& operator++(T*VQ&);
// T*VQ& operator--(T*VQ&);
// T* operator++(T*VQ&, int);
// T* operator--(T*VQ&, int);
void addPlusPlusMinusMinusPointerOverloads() {
for (QualType PtrTy : CandidateTypes[0].pointer_types()) {
// Skip pointer types that aren't pointers to object types.
if (!PtrTy->getPointeeType()->isObjectType())
continue;
addPlusPlusMinusMinusStyleOverloads(
PtrTy,
(!PtrTy.isVolatileQualified() &&
VisibleTypeConversionsQuals.hasVolatile()),
(!PtrTy.isRestrictQualified() &&
VisibleTypeConversionsQuals.hasRestrict()));
}
}
// C++ [over.built]p6:
// For every cv-qualified or cv-unqualified object type T, there
// exist candidate operator functions of the form
//
// T& operator*(T*);
//
// C++ [over.built]p7:
// For every function type T that does not have cv-qualifiers or a
// ref-qualifier, there exist candidate operator functions of the form
// T& operator*(T*);
void addUnaryStarPointerOverloads() {
for (QualType ParamTy : CandidateTypes[0].pointer_types()) {
QualType PointeeTy = ParamTy->getPointeeType();
if (!PointeeTy->isObjectType() && !PointeeTy->isFunctionType())
continue;
if (const FunctionProtoType *Proto =PointeeTy->getAs<FunctionProtoType>())
if (Proto->getMethodQuals() || Proto->getRefQualifier())
continue;
S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet);
}
}
// C++ [over.built]p9:
// For every promoted arithmetic type T, there exist candidate
// operator functions of the form
//
// T operator+(T);
// T operator-(T);
void addUnaryPlusOrMinusArithmeticOverloads() {
if (!HasArithmeticOrEnumeralCandidateType)
return;
for (unsigned Arith = FirstPromotedArithmeticType;
Arith < LastPromotedArithmeticType; ++Arith) {
QualType ArithTy = ArithmeticTypes[Arith];
S.AddBuiltinCandidate(&ArithTy, Args, CandidateSet);
}
// Extension: We also add these operators for vector types.
for (QualType VecTy : CandidateTypes[0].vector_types())
S.AddBuiltinCandidate(&VecTy, Args, CandidateSet);
}
// C++ [over.built]p8:
// For every type T, there exist candidate operator functions of
// the form
//
// T* operator+(T*);
void addUnaryPlusPointerOverloads() {
for (QualType ParamTy : CandidateTypes[0].pointer_types())
S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet);
}
// C++ [over.built]p10:
// For every promoted integral type T, there exist candidate
// operator functions of the form
//
// T operator~(T);
void addUnaryTildePromotedIntegralOverloads() {
if (!HasArithmeticOrEnumeralCandidateType)
return;
for (unsigned Int = FirstPromotedIntegralType;
Int < LastPromotedIntegralType; ++Int) {
QualType IntTy = ArithmeticTypes[Int];
S.AddBuiltinCandidate(&IntTy, Args, CandidateSet);
}
// Extension: We also add this operator for vector types.
for (QualType VecTy : CandidateTypes[0].vector_types())
S.AddBuiltinCandidate(&VecTy, Args, CandidateSet);
}
// C++ [over.match.oper]p16:
// For every pointer to member type T or type std::nullptr_t, there
// exist candidate operator functions of the form
//
// bool operator==(T,T);
// bool operator!=(T,T);
void addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads() {
/// Set of (canonical) types that we've already handled.
llvm::SmallPtrSet<QualType, 8> AddedTypes;
for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
for (QualType MemPtrTy : CandidateTypes[ArgIdx].member_pointer_types()) {
// Don't add the same builtin candidate twice.
if (!AddedTypes.insert(S.Context.getCanonicalType(MemPtrTy)).second)
continue;
QualType ParamTypes[2] = {MemPtrTy, MemPtrTy};
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
if (CandidateTypes[ArgIdx].hasNullPtrType()) {
CanQualType NullPtrTy = S.Context.getCanonicalType(S.Context.NullPtrTy);
if (AddedTypes.insert(NullPtrTy).second) {
QualType ParamTypes[2] = { NullPtrTy, NullPtrTy };
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
}
}
}
// C++ [over.built]p15:
//
// For every T, where T is an enumeration type or a pointer type,
// there exist candidate operator functions of the form
//
// bool operator<(T, T);
// bool operator>(T, T);
// bool operator<=(T, T);
// bool operator>=(T, T);
// bool operator==(T, T);
// bool operator!=(T, T);
// R operator<=>(T, T)
void addGenericBinaryPointerOrEnumeralOverloads(bool IsSpaceship) {
// C++ [over.match.oper]p3:
// [...]the built-in candidates include all of the candidate operator
// functions defined in 13.6 that, compared to the given operator, [...]
// do not have the same parameter-type-list as any non-template non-member
// candidate.
//
// Note that in practice, this only affects enumeration types because there
// aren't any built-in candidates of record type, and a user-defined operator
// must have an operand of record or enumeration type. Also, the only other
// overloaded operator with enumeration arguments, operator=,
// cannot be overloaded for enumeration types, so this is the only place
// where we must suppress candidates like this.
llvm::DenseSet<std::pair<CanQualType, CanQualType> >
UserDefinedBinaryOperators;
for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
if (!CandidateTypes[ArgIdx].enumeration_types().empty()) {
for (OverloadCandidateSet::iterator C = CandidateSet.begin(),
CEnd = CandidateSet.end();
C != CEnd; ++C) {
if (!C->Viable || !C->Function || C->Function->getNumParams() != 2)
continue;
if (C->Function->isFunctionTemplateSpecialization())
continue;
// We interpret "same parameter-type-list" as applying to the
// "synthesized candidate, with the order of the two parameters
// reversed", not to the original function.
bool Reversed = C->isReversed();
QualType FirstParamType = C->Function->getParamDecl(Reversed ? 1 : 0)
->getType()
.getUnqualifiedType();
QualType SecondParamType = C->Function->getParamDecl(Reversed ? 0 : 1)
->getType()
.getUnqualifiedType();
// Skip if either parameter isn't of enumeral type.
if (!FirstParamType->isEnumeralType() ||
!SecondParamType->isEnumeralType())
continue;
// Add this operator to the set of known user-defined operators.
UserDefinedBinaryOperators.insert(
std::make_pair(S.Context.getCanonicalType(FirstParamType),
S.Context.getCanonicalType(SecondParamType)));
}
}
}
/// Set of (canonical) types that we've already handled.
llvm::SmallPtrSet<QualType, 8> AddedTypes;
for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
for (QualType PtrTy : CandidateTypes[ArgIdx].pointer_types()) {
// Don't add the same builtin candidate twice.
if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second)
continue;
if (IsSpaceship && PtrTy->isFunctionPointerType())
continue;
QualType ParamTypes[2] = {PtrTy, PtrTy};
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
for (QualType EnumTy : CandidateTypes[ArgIdx].enumeration_types()) {
CanQualType CanonType = S.Context.getCanonicalType(EnumTy);
// Don't add the same builtin candidate twice, or if a user defined
// candidate exists.
if (!AddedTypes.insert(CanonType).second ||
UserDefinedBinaryOperators.count(std::make_pair(CanonType,
CanonType)))
continue;
QualType ParamTypes[2] = {EnumTy, EnumTy};
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
}
}
// C++ [over.built]p13:
//
// For every cv-qualified or cv-unqualified object type T
// there exist candidate operator functions of the form
//
// T* operator+(T*, ptrdiff_t);
// T& operator[](T*, ptrdiff_t); [BELOW]
// T* operator-(T*, ptrdiff_t);
// T* operator+(ptrdiff_t, T*);
// T& operator[](ptrdiff_t, T*); [BELOW]
//
// C++ [over.built]p14:
//
// For every T, where T is a pointer to object type, there
// exist candidate operator functions of the form
//
// ptrdiff_t operator-(T, T);
void addBinaryPlusOrMinusPointerOverloads(OverloadedOperatorKind Op) {
/// Set of (canonical) types that we've already handled.
llvm::SmallPtrSet<QualType, 8> AddedTypes;
for (int Arg = 0; Arg < 2; ++Arg) {
QualType AsymmetricParamTypes[2] = {
S.Context.getPointerDiffType(),
S.Context.getPointerDiffType(),
};
for (QualType PtrTy : CandidateTypes[Arg].pointer_types()) {
QualType PointeeTy = PtrTy->getPointeeType();
if (!PointeeTy->isObjectType())
continue;
AsymmetricParamTypes[Arg] = PtrTy;
if (Arg == 0 || Op == OO_Plus) {
// operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t)
// T* operator+(ptrdiff_t, T*);
S.AddBuiltinCandidate(AsymmetricParamTypes, Args, CandidateSet);
}
if (Op == OO_Minus) {
// ptrdiff_t operator-(T, T);
if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second)
continue;
QualType ParamTypes[2] = {PtrTy, PtrTy};
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
}
}
}
// C++ [over.built]p12:
//
// For every pair of promoted arithmetic types L and R, there
// exist candidate operator functions of the form
//
// LR operator*(L, R);
// LR operator/(L, R);
// LR operator+(L, R);
// LR operator-(L, R);
// bool operator<(L, R);
// bool operator>(L, R);
// bool operator<=(L, R);
// bool operator>=(L, R);
// bool operator==(L, R);
// bool operator!=(L, R);
//
// where LR is the result of the usual arithmetic conversions
// between types L and R.
//
// C++ [over.built]p24:
//
// For every pair of promoted arithmetic types L and R, there exist
// candidate operator functions of the form
//
// LR operator?(bool, L, R);
//
// where LR is the result of the usual arithmetic conversions
// between types L and R.
// Our candidates ignore the first parameter.
void addGenericBinaryArithmeticOverloads() {
if (!HasArithmeticOrEnumeralCandidateType)
return;
for (unsigned Left = FirstPromotedArithmeticType;
Left < LastPromotedArithmeticType; ++Left) {
for (unsigned Right = FirstPromotedArithmeticType;
Right < LastPromotedArithmeticType; ++Right) {
QualType LandR[2] = { ArithmeticTypes[Left],
ArithmeticTypes[Right] };
S.AddBuiltinCandidate(LandR, Args, CandidateSet);
}
}
// Extension: Add the binary operators ==, !=, <, <=, >=, >, *, /, and the
// conditional operator for vector types.
for (QualType Vec1Ty : CandidateTypes[0].vector_types())
for (QualType Vec2Ty : CandidateTypes[1].vector_types()) {
QualType LandR[2] = {Vec1Ty, Vec2Ty};
S.AddBuiltinCandidate(LandR, Args, CandidateSet);
}
}
/// Add binary operator overloads for each candidate matrix type M1, M2:
/// * (M1, M1) -> M1
/// * (M1, M1.getElementType()) -> M1
/// * (M2.getElementType(), M2) -> M2
/// * (M2, M2) -> M2 // Only if M2 is not part of CandidateTypes[0].
void addMatrixBinaryArithmeticOverloads() {
if (!HasArithmeticOrEnumeralCandidateType)
return;
for (QualType M1 : CandidateTypes[0].matrix_types()) {
AddCandidate(M1, cast<MatrixType>(M1)->getElementType());
AddCandidate(M1, M1);
}
for (QualType M2 : CandidateTypes[1].matrix_types()) {
AddCandidate(cast<MatrixType>(M2)->getElementType(), M2);
if (!CandidateTypes[0].containsMatrixType(M2))
AddCandidate(M2, M2);
}
}
// C++2a [over.built]p14:
//
// For every integral type T there exists a candidate operator function
// of the form
//
// std::strong_ordering operator<=>(T, T)
//
// C++2a [over.built]p15:
//
// For every pair of floating-point types L and R, there exists a candidate
// operator function of the form
//
// std::partial_ordering operator<=>(L, R);
//
// FIXME: The current specification for integral types doesn't play nice with
// the direction of p0946r0, which allows mixed integral and unscoped-enum
// comparisons. Under the current spec this can lead to ambiguity during
// overload resolution. For example:
//
// enum A : int {a};
// auto x = (a <=> (long)42);
//
// error: call is ambiguous for arguments 'A' and 'long'.
// note: candidate operator<=>(int, int)
// note: candidate operator<=>(long, long)
//
// To avoid this error, this function deviates from the specification and adds
// the mixed overloads `operator<=>(L, R)` where L and R are promoted
// arithmetic types (the same as the generic relational overloads).
//
// For now this function acts as a placeholder.
void addThreeWayArithmeticOverloads() {
addGenericBinaryArithmeticOverloads();
}
// C++ [over.built]p17:
//
// For every pair of promoted integral types L and R, there
// exist candidate operator functions of the form
//
// LR operator%(L, R);
// LR operator&(L, R);
// LR operator^(L, R);
// LR operator|(L, R);
// L operator<<(L, R);
// L operator>>(L, R);
//
// where LR is the result of the usual arithmetic conversions
// between types L and R.
void addBinaryBitwiseArithmeticOverloads() {
if (!HasArithmeticOrEnumeralCandidateType)
return;
for (unsigned Left = FirstPromotedIntegralType;
Left < LastPromotedIntegralType; ++Left) {
for (unsigned Right = FirstPromotedIntegralType;
Right < LastPromotedIntegralType; ++Right) {
QualType LandR[2] = { ArithmeticTypes[Left],
ArithmeticTypes[Right] };
S.AddBuiltinCandidate(LandR, Args, CandidateSet);
}
}
}
// C++ [over.built]p20:
//
// For every pair (T, VQ), where T is an enumeration or
// pointer to member type and VQ is either volatile or
// empty, there exist candidate operator functions of the form
//
// VQ T& operator=(VQ T&, T);
void addAssignmentMemberPointerOrEnumeralOverloads() {
/// Set of (canonical) types that we've already handled.
llvm::SmallPtrSet<QualType, 8> AddedTypes;
for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
for (QualType EnumTy : CandidateTypes[ArgIdx].enumeration_types()) {
if (!AddedTypes.insert(S.Context.getCanonicalType(EnumTy)).second)
continue;
AddBuiltinAssignmentOperatorCandidates(S, EnumTy, Args, CandidateSet);
}
for (QualType MemPtrTy : CandidateTypes[ArgIdx].member_pointer_types()) {
if (!AddedTypes.insert(S.Context.getCanonicalType(MemPtrTy)).second)
continue;
AddBuiltinAssignmentOperatorCandidates(S, MemPtrTy, Args, CandidateSet);
}
}
}
// C++ [over.built]p19:
//
// For every pair (T, VQ), where T is any type and VQ is either
// volatile or empty, there exist candidate operator functions
// of the form
//
// T*VQ& operator=(T*VQ&, T*);
//
// C++ [over.built]p21:
//
// For every pair (T, VQ), where T is a cv-qualified or
// cv-unqualified object type and VQ is either volatile or
// empty, there exist candidate operator functions of the form
//
// T*VQ& operator+=(T*VQ&, ptrdiff_t);
// T*VQ& operator-=(T*VQ&, ptrdiff_t);
void addAssignmentPointerOverloads(bool isEqualOp) {
/// Set of (canonical) types that we've already handled.
llvm::SmallPtrSet<QualType, 8> AddedTypes;
for (QualType PtrTy : CandidateTypes[0].pointer_types()) {
// If this is operator=, keep track of the builtin candidates we added.
if (isEqualOp)
AddedTypes.insert(S.Context.getCanonicalType(PtrTy));
else if (!PtrTy->getPointeeType()->isObjectType())
continue;
// non-volatile version
QualType ParamTypes[2] = {
S.Context.getLValueReferenceType(PtrTy),
isEqualOp ? PtrTy : S.Context.getPointerDiffType(),
};
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/ isEqualOp);
bool NeedVolatile = !PtrTy.isVolatileQualified() &&
VisibleTypeConversionsQuals.hasVolatile();
if (NeedVolatile) {
// volatile version
ParamTypes[0] =
S.Context.getLValueReferenceType(S.Context.getVolatileType(PtrTy));
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/isEqualOp);
}
if (!PtrTy.isRestrictQualified() &&
VisibleTypeConversionsQuals.hasRestrict()) {
// restrict version
ParamTypes[0] =
S.Context.getLValueReferenceType(S.Context.getRestrictType(PtrTy));
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/isEqualOp);
if (NeedVolatile) {
// volatile restrict version
ParamTypes[0] =
S.Context.getLValueReferenceType(S.Context.getCVRQualifiedType(
PtrTy, (Qualifiers::Volatile | Qualifiers::Restrict)));
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/isEqualOp);
}
}
}
if (isEqualOp) {
for (QualType PtrTy : CandidateTypes[1].pointer_types()) {
// Make sure we don't add the same candidate twice.
if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second)
continue;
QualType ParamTypes[2] = {
S.Context.getLValueReferenceType(PtrTy),
PtrTy,
};
// non-volatile version
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/true);
bool NeedVolatile = !PtrTy.isVolatileQualified() &&
VisibleTypeConversionsQuals.hasVolatile();
if (NeedVolatile) {
// volatile version
ParamTypes[0] = S.Context.getLValueReferenceType(
S.Context.getVolatileType(PtrTy));
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/true);
}
if (!PtrTy.isRestrictQualified() &&
VisibleTypeConversionsQuals.hasRestrict()) {
// restrict version
ParamTypes[0] = S.Context.getLValueReferenceType(
S.Context.getRestrictType(PtrTy));
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/true);
if (NeedVolatile) {
// volatile restrict version
ParamTypes[0] =
S.Context.getLValueReferenceType(S.Context.getCVRQualifiedType(
PtrTy, (Qualifiers::Volatile | Qualifiers::Restrict)));
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/true);
}
}
}
}
}
// C++ [over.built]p18:
//
// For every triple (L, VQ, R), where L is an arithmetic type,
// VQ is either volatile or empty, and R is a promoted
// arithmetic type, there exist candidate operator functions of
// the form
//
// VQ L& operator=(VQ L&, R);
// VQ L& operator*=(VQ L&, R);
// VQ L& operator/=(VQ L&, R);
// VQ L& operator+=(VQ L&, R);
// VQ L& operator-=(VQ L&, R);
void addAssignmentArithmeticOverloads(bool isEqualOp) {
if (!HasArithmeticOrEnumeralCandidateType)
return;
for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) {
for (unsigned Right = FirstPromotedArithmeticType;
Right < LastPromotedArithmeticType; ++Right) {
QualType ParamTypes[2];
ParamTypes[1] = ArithmeticTypes[Right];
auto LeftBaseTy = AdjustAddressSpaceForBuiltinOperandType(
S, ArithmeticTypes[Left], Args[0]);
// Add this built-in operator as a candidate (VQ is empty).
ParamTypes[0] = S.Context.getLValueReferenceType(LeftBaseTy);
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/isEqualOp);
// Add this built-in operator as a candidate (VQ is 'volatile').
if (VisibleTypeConversionsQuals.hasVolatile()) {
ParamTypes[0] = S.Context.getVolatileType(LeftBaseTy);
ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/isEqualOp);
}
}
}
// Extension: Add the binary operators =, +=, -=, *=, /= for vector types.
for (QualType Vec1Ty : CandidateTypes[0].vector_types())
for (QualType Vec2Ty : CandidateTypes[0].vector_types()) {
QualType ParamTypes[2];
ParamTypes[1] = Vec2Ty;
// Add this built-in operator as a candidate (VQ is empty).
ParamTypes[0] = S.Context.getLValueReferenceType(Vec1Ty);
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/isEqualOp);
// Add this built-in operator as a candidate (VQ is 'volatile').
if (VisibleTypeConversionsQuals.hasVolatile()) {
ParamTypes[0] = S.Context.getVolatileType(Vec1Ty);
ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/isEqualOp);
}
}
}
// C++ [over.built]p22:
//
// For every triple (L, VQ, R), where L is an integral type, VQ
// is either volatile or empty, and R is a promoted integral
// type, there exist candidate operator functions of the form
//
// VQ L& operator%=(VQ L&, R);
// VQ L& operator<<=(VQ L&, R);
// VQ L& operator>>=(VQ L&, R);
// VQ L& operator&=(VQ L&, R);
// VQ L& operator^=(VQ L&, R);
// VQ L& operator|=(VQ L&, R);
void addAssignmentIntegralOverloads() {
if (!HasArithmeticOrEnumeralCandidateType)
return;
for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) {
for (unsigned Right = FirstPromotedIntegralType;
Right < LastPromotedIntegralType; ++Right) {
QualType ParamTypes[2];
ParamTypes[1] = ArithmeticTypes[Right];
auto LeftBaseTy = AdjustAddressSpaceForBuiltinOperandType(
S, ArithmeticTypes[Left], Args[0]);
// Add this built-in operator as a candidate (VQ is empty).
ParamTypes[0] = S.Context.getLValueReferenceType(LeftBaseTy);
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
if (VisibleTypeConversionsQuals.hasVolatile()) {
// Add this built-in operator as a candidate (VQ is 'volatile').
ParamTypes[0] = LeftBaseTy;
ParamTypes[0] = S.Context.getVolatileType(ParamTypes[0]);
ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
}
}
}
// C++ [over.operator]p23:
//
// There also exist candidate operator functions of the form
//
// bool operator!(bool);
// bool operator&&(bool, bool);
// bool operator||(bool, bool);
void addExclaimOverload() {
QualType ParamTy = S.Context.BoolTy;
S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet,
/*IsAssignmentOperator=*/false,
/*NumContextualBoolArguments=*/1);
}
void addAmpAmpOrPipePipeOverload() {
QualType ParamTypes[2] = { S.Context.BoolTy, S.Context.BoolTy };
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
/*IsAssignmentOperator=*/false,
/*NumContextualBoolArguments=*/2);
}
// C++ [over.built]p13:
//
// For every cv-qualified or cv-unqualified object type T there
// exist candidate operator functions of the form
//
// T* operator+(T*, ptrdiff_t); [ABOVE]
// T& operator[](T*, ptrdiff_t);
// T* operator-(T*, ptrdiff_t); [ABOVE]
// T* operator+(ptrdiff_t, T*); [ABOVE]
// T& operator[](ptrdiff_t, T*);
void addSubscriptOverloads() {
for (QualType PtrTy : CandidateTypes[0].pointer_types()) {
QualType ParamTypes[2] = {PtrTy, S.Context.getPointerDiffType()};
QualType PointeeType = PtrTy->getPointeeType();
if (!PointeeType->isObjectType())
continue;
// T& operator[](T*, ptrdiff_t)
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
for (QualType PtrTy : CandidateTypes[1].pointer_types()) {
QualType ParamTypes[2] = {S.Context.getPointerDiffType(), PtrTy};
QualType PointeeType = PtrTy->getPointeeType();
if (!PointeeType->isObjectType())
continue;
// T& operator[](ptrdiff_t, T*)
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
}
// C++ [over.built]p11:
// For every quintuple (C1, C2, T, CV1, CV2), where C2 is a class type,
// C1 is the same type as C2 or is a derived class of C2, T is an object
// type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
// there exist candidate operator functions of the form
//
// CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
//
// where CV12 is the union of CV1 and CV2.
void addArrowStarOverloads() {
for (QualType PtrTy : CandidateTypes[0].pointer_types()) {
QualType C1Ty = PtrTy;
QualType C1;
QualifierCollector Q1;
C1 = QualType(Q1.strip(C1Ty->getPointeeType()), 0);
if (!isa<RecordType>(C1))
continue;
// heuristic to reduce number of builtin candidates in the set.
// Add volatile/restrict version only if there are conversions to a
// volatile/restrict type.
if (!VisibleTypeConversionsQuals.hasVolatile() && Q1.hasVolatile())
continue;
if (!VisibleTypeConversionsQuals.hasRestrict() && Q1.hasRestrict())
continue;
for (QualType MemPtrTy : CandidateTypes[1].member_pointer_types()) {
const MemberPointerType *mptr = cast<MemberPointerType>(MemPtrTy);
QualType C2 = QualType(mptr->getClass(), 0);
C2 = C2.getUnqualifiedType();
if (C1 != C2 && !S.IsDerivedFrom(CandidateSet.getLocation(), C1, C2))
break;
QualType ParamTypes[2] = {PtrTy, MemPtrTy};
// build CV12 T&
QualType T = mptr->getPointeeType();
if (!VisibleTypeConversionsQuals.hasVolatile() &&
T.isVolatileQualified())
continue;
if (!VisibleTypeConversionsQuals.hasRestrict() &&
T.isRestrictQualified())
continue;
T = Q1.apply(S.Context, T);
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
}
}
// Note that we don't consider the first argument, since it has been
// contextually converted to bool long ago. The candidates below are
// therefore added as binary.
//
// C++ [over.built]p25:
// For every type T, where T is a pointer, pointer-to-member, or scoped
// enumeration type, there exist candidate operator functions of the form
//
// T operator?(bool, T, T);
//
void addConditionalOperatorOverloads() {
/// Set of (canonical) types that we've already handled.
llvm::SmallPtrSet<QualType, 8> AddedTypes;
for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
for (QualType PtrTy : CandidateTypes[ArgIdx].pointer_types()) {
if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second)
continue;
QualType ParamTypes[2] = {PtrTy, PtrTy};
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
for (QualType MemPtrTy : CandidateTypes[ArgIdx].member_pointer_types()) {
if (!AddedTypes.insert(S.Context.getCanonicalType(MemPtrTy)).second)
continue;
QualType ParamTypes[2] = {MemPtrTy, MemPtrTy};
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
if (S.getLangOpts().CPlusPlus11) {
for (QualType EnumTy : CandidateTypes[ArgIdx].enumeration_types()) {
if (!EnumTy->castAs<EnumType>()->getDecl()->isScoped())
continue;
if (!AddedTypes.insert(S.Context.getCanonicalType(EnumTy)).second)
continue;
QualType ParamTypes[2] = {EnumTy, EnumTy};
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
}
}
}
}
};
} // end anonymous namespace
/// AddBuiltinOperatorCandidates - Add the appropriate built-in
/// operator overloads to the candidate set (C++ [over.built]), based
/// on the operator @p Op and the arguments given. For example, if the
/// operator is a binary '+', this routine might add "int
/// operator+(int, int)" to cover integer addition.
void Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,
SourceLocation OpLoc,
ArrayRef<Expr *> Args,
OverloadCandidateSet &CandidateSet) {
// Find all of the types that the arguments can convert to, but only
// if the operator we're looking at has built-in operator candidates
// that make use of these types. Also record whether we encounter non-record
// candidate types or either arithmetic or enumeral candidate types.
Qualifiers VisibleTypeConversionsQuals;
VisibleTypeConversionsQuals.addConst();
for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx)
VisibleTypeConversionsQuals += CollectVRQualifiers(Context, Args[ArgIdx]);
bool HasNonRecordCandidateType = false;
bool HasArithmeticOrEnumeralCandidateType = false;
SmallVector<BuiltinCandidateTypeSet, 2> CandidateTypes;
for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
CandidateTypes.emplace_back(*this);
CandidateTypes[ArgIdx].AddTypesConvertedFrom(Args[ArgIdx]->getType(),
OpLoc,
true,
(Op == OO_Exclaim ||
Op == OO_AmpAmp ||
Op == OO_PipePipe),
VisibleTypeConversionsQuals);
HasNonRecordCandidateType = HasNonRecordCandidateType ||
CandidateTypes[ArgIdx].hasNonRecordTypes();
HasArithmeticOrEnumeralCandidateType =
HasArithmeticOrEnumeralCandidateType ||
CandidateTypes[ArgIdx].hasArithmeticOrEnumeralTypes();
}
// Exit early when no non-record types have been added to the candidate set
// for any of the arguments to the operator.
//
// We can't exit early for !, ||, or &&, since there we have always have
// 'bool' overloads.
if (!HasNonRecordCandidateType &&
!(Op == OO_Exclaim || Op == OO_AmpAmp || Op == OO_PipePipe))
return;
// Setup an object to manage the common state for building overloads.
BuiltinOperatorOverloadBuilder OpBuilder(*this, Args,
VisibleTypeConversionsQuals,
HasArithmeticOrEnumeralCandidateType,
CandidateTypes, CandidateSet);
// Dispatch over the operation to add in only those overloads which apply.
switch (Op) {
case OO_None:
case NUM_OVERLOADED_OPERATORS:
llvm_unreachable("Expected an overloaded operator");
case OO_New:
case OO_Delete:
case OO_Array_New:
case OO_Array_Delete:
case OO_Call:
llvm_unreachable(
"Special operators don't use AddBuiltinOperatorCandidates");
case OO_Comma:
case OO_Arrow:
case OO_Coawait:
// C++ [over.match.oper]p3:
// -- For the operator ',', the unary operator '&', the
// operator '->', or the operator 'co_await', the
// built-in candidates set is empty.
break;
case OO_Plus: // '+' is either unary or binary
if (Args.size() == 1)
OpBuilder.addUnaryPlusPointerOverloads();
LLVM_FALLTHROUGH;
case OO_Minus: // '-' is either unary or binary
if (Args.size() == 1) {
OpBuilder.addUnaryPlusOrMinusArithmeticOverloads();
} else {
OpBuilder.addBinaryPlusOrMinusPointerOverloads(Op);
OpBuilder.addGenericBinaryArithmeticOverloads();
OpBuilder.addMatrixBinaryArithmeticOverloads();
}
break;
case OO_Star: // '*' is either unary or binary
if (Args.size() == 1)
OpBuilder.addUnaryStarPointerOverloads();
else {
OpBuilder.addGenericBinaryArithmeticOverloads();
OpBuilder.addMatrixBinaryArithmeticOverloads();
}
break;
case OO_Slash:
OpBuilder.addGenericBinaryArithmeticOverloads();
break;
case OO_PlusPlus:
case OO_MinusMinus:
OpBuilder.addPlusPlusMinusMinusArithmeticOverloads(Op);
OpBuilder.addPlusPlusMinusMinusPointerOverloads();
break;
case OO_EqualEqual:
case OO_ExclaimEqual:
OpBuilder.addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads();
OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(/*IsSpaceship=*/false);
OpBuilder.addGenericBinaryArithmeticOverloads();
break;
case OO_Less:
case OO_Greater:
case OO_LessEqual:
case OO_GreaterEqual:
OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(/*IsSpaceship=*/false);
OpBuilder.addGenericBinaryArithmeticOverloads();
break;
case OO_Spaceship:
OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(/*IsSpaceship=*/true);
OpBuilder.addThreeWayArithmeticOverloads();
break;
case OO_Percent:
case OO_Caret:
case OO_Pipe:
case OO_LessLess:
case OO_GreaterGreater:
OpBuilder.addBinaryBitwiseArithmeticOverloads();
break;
case OO_Amp: // '&' is either unary or binary
if (Args.size() == 1)
// C++ [over.match.oper]p3:
// -- For the operator ',', the unary operator '&', or the
// operator '->', the built-in candidates set is empty.
break;
OpBuilder.addBinaryBitwiseArithmeticOverloads();
break;
case OO_Tilde:
OpBuilder.addUnaryTildePromotedIntegralOverloads();
break;
case OO_Equal:
OpBuilder.addAssignmentMemberPointerOrEnumeralOverloads();
LLVM_FALLTHROUGH;
case OO_PlusEqual:
case OO_MinusEqual:
OpBuilder.addAssignmentPointerOverloads(Op == OO_Equal);
LLVM_FALLTHROUGH;
case OO_StarEqual:
case OO_SlashEqual:
OpBuilder.addAssignmentArithmeticOverloads(Op == OO_Equal);
break;
case OO_PercentEqual:
case OO_LessLessEqual:
case OO_GreaterGreaterEqual:
case OO_AmpEqual:
case OO_CaretEqual:
case OO_PipeEqual:
OpBuilder.addAssignmentIntegralOverloads();
break;
case OO_Exclaim:
OpBuilder.addExclaimOverload();
break;
case OO_AmpAmp:
case OO_PipePipe:
OpBuilder.addAmpAmpOrPipePipeOverload();
break;
case OO_Subscript:
OpBuilder.addSubscriptOverloads();
break;
case OO_ArrowStar:
OpBuilder.addArrowStarOverloads();
break;
case OO_Conditional:
OpBuilder.addConditionalOperatorOverloads();
OpBuilder.addGenericBinaryArithmeticOverloads();
break;
}
}
/// Add function candidates found via argument-dependent lookup
/// to the set of overloading candidates.
///
/// This routine performs argument-dependent name lookup based on the
/// given function name (which may also be an operator name) and adds
/// all of the overload candidates found by ADL to the overload
/// candidate set (C++ [basic.lookup.argdep]).
void
Sema::AddArgumentDependentLookupCandidates(DeclarationName Name,
SourceLocation Loc,
ArrayRef<Expr *> Args,
TemplateArgumentListInfo *ExplicitTemplateArgs,
OverloadCandidateSet& CandidateSet,
bool PartialOverloading) {
ADLResult Fns;
// FIXME: This approach for uniquing ADL results (and removing
// redundant candidates from the set) relies on pointer-equality,
// which means we need to key off the canonical decl. However,
// always going back to the canonical decl might not get us the
// right set of default arguments. What default arguments are
// we supposed to consider on ADL candidates, anyway?
// FIXME: Pass in the explicit template arguments?
ArgumentDependentLookup(Name, Loc, Args, Fns);
// Erase all of the candidates we already knew about.
for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(),
CandEnd = CandidateSet.end();
Cand != CandEnd; ++Cand)
if (Cand->Function) {
Fns.erase(Cand->Function);
if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate())
Fns.erase(FunTmpl);
}
// For each of the ADL candidates we found, add it to the overload
// set.
for (ADLResult::iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) {
DeclAccessPair FoundDecl = DeclAccessPair::make(*I, AS_none);
if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
if (ExplicitTemplateArgs)
continue;
AddOverloadCandidate(
FD, FoundDecl, Args, CandidateSet, /*SuppressUserConversions=*/false,
PartialOverloading, /*AllowExplicit=*/true,
/*AllowExplicitConversions=*/false, ADLCallKind::UsesADL);
if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD)) {
AddOverloadCandidate(
FD, FoundDecl, {Args[1], Args[0]}, CandidateSet,
/*SuppressUserConversions=*/false, PartialOverloading,
/*AllowExplicit=*/true, /*AllowExplicitConversions=*/false,
ADLCallKind::UsesADL, None, OverloadCandidateParamOrder::Reversed);
}
} else {
auto *FTD = cast<FunctionTemplateDecl>(*I);
AddTemplateOverloadCandidate(
FTD, FoundDecl, ExplicitTemplateArgs, Args, CandidateSet,
/*SuppressUserConversions=*/false, PartialOverloading,
/*AllowExplicit=*/true, ADLCallKind::UsesADL);
if (CandidateSet.getRewriteInfo().shouldAddReversed(
Context, FTD->getTemplatedDecl())) {
AddTemplateOverloadCandidate(
FTD, FoundDecl, ExplicitTemplateArgs, {Args[1], Args[0]},
CandidateSet, /*SuppressUserConversions=*/false, PartialOverloading,
/*AllowExplicit=*/true, ADLCallKind::UsesADL,
OverloadCandidateParamOrder::Reversed);
}
}
}
}
namespace {
enum class Comparison { Equal, Better, Worse };
}
/// Compares the enable_if attributes of two FunctionDecls, for the purposes of
/// overload resolution.
///
/// Cand1's set of enable_if attributes are said to be "better" than Cand2's iff
/// Cand1's first N enable_if attributes have precisely the same conditions as
/// Cand2's first N enable_if attributes (where N = the number of enable_if
/// attributes on Cand2), and Cand1 has more than N enable_if attributes.
///
/// Note that you can have a pair of candidates such that Cand1's enable_if
/// attributes are worse than Cand2's, and Cand2's enable_if attributes are
/// worse than Cand1's.
static Comparison compareEnableIfAttrs(const Sema &S, const FunctionDecl *Cand1,
const FunctionDecl *Cand2) {
// Common case: One (or both) decls don't have enable_if attrs.
bool Cand1Attr = Cand1->hasAttr<EnableIfAttr>();
bool Cand2Attr = Cand2->hasAttr<EnableIfAttr>();
if (!Cand1Attr || !Cand2Attr) {
if (Cand1Attr == Cand2Attr)
return Comparison::Equal;
return Cand1Attr ? Comparison::Better : Comparison::Worse;
}
auto Cand1Attrs = Cand1->specific_attrs<EnableIfAttr>();
auto Cand2Attrs = Cand2->specific_attrs<EnableIfAttr>();
llvm::FoldingSetNodeID Cand1ID, Cand2ID;
for (auto Pair : zip_longest(Cand1Attrs, Cand2Attrs)) {
Optional<EnableIfAttr *> Cand1A = std::get<0>(Pair);
Optional<EnableIfAttr *> Cand2A = std::get<1>(Pair);
// It's impossible for Cand1 to be better than (or equal to) Cand2 if Cand1
// has fewer enable_if attributes than Cand2, and vice versa.
if (!Cand1A)
return Comparison::Worse;
if (!Cand2A)
return Comparison::Better;
Cand1ID.clear();
Cand2ID.clear();
(*Cand1A)->getCond()->Profile(Cand1ID, S.getASTContext(), true);
(*Cand2A)->getCond()->Profile(Cand2ID, S.getASTContext(), true);
if (Cand1ID != Cand2ID)
return Comparison::Worse;
}
return Comparison::Equal;
}
static Comparison
isBetterMultiversionCandidate(const OverloadCandidate &Cand1,
const OverloadCandidate &Cand2) {
if (!Cand1.Function || !Cand1.Function->isMultiVersion() || !Cand2.Function ||
!Cand2.Function->isMultiVersion())
return Comparison::Equal;
// If both are invalid, they are equal. If one of them is invalid, the other
// is better.
if (Cand1.Function->isInvalidDecl()) {
if (Cand2.Function->isInvalidDecl())
return Comparison::Equal;
return Comparison::Worse;
}
if (Cand2.Function->isInvalidDecl())
return Comparison::Better;
// If this is a cpu_dispatch/cpu_specific multiversion situation, prefer
// cpu_dispatch, else arbitrarily based on the identifiers.
bool Cand1CPUDisp = Cand1.Function->hasAttr<CPUDispatchAttr>();
bool Cand2CPUDisp = Cand2.Function->hasAttr<CPUDispatchAttr>();
const auto *Cand1CPUSpec = Cand1.Function->getAttr<CPUSpecificAttr>();
const auto *Cand2CPUSpec = Cand2.Function->getAttr<CPUSpecificAttr>();
if (!Cand1CPUDisp && !Cand2CPUDisp && !Cand1CPUSpec && !Cand2CPUSpec)
return Comparison::Equal;
if (Cand1CPUDisp && !Cand2CPUDisp)
return Comparison::Better;
if (Cand2CPUDisp && !Cand1CPUDisp)
return Comparison::Worse;
if (Cand1CPUSpec && Cand2CPUSpec) {
if (Cand1CPUSpec->cpus_size() != Cand2CPUSpec->cpus_size())
return Cand1CPUSpec->cpus_size() < Cand2CPUSpec->cpus_size()
? Comparison::Better
: Comparison::Worse;
std::pair<CPUSpecificAttr::cpus_iterator, CPUSpecificAttr::cpus_iterator>
FirstDiff = std::mismatch(
Cand1CPUSpec->cpus_begin(), Cand1CPUSpec->cpus_end(),
Cand2CPUSpec->cpus_begin(),
[](const IdentifierInfo *LHS, const IdentifierInfo *RHS) {
return LHS->getName() == RHS->getName();
});
assert(FirstDiff.first != Cand1CPUSpec->cpus_end() &&
"Two different cpu-specific versions should not have the same "
"identifier list, otherwise they'd be the same decl!");
return (*FirstDiff.first)->getName() < (*FirstDiff.second)->getName()
? Comparison::Better
: Comparison::Worse;
}
llvm_unreachable("No way to get here unless both had cpu_dispatch");
}
/// Compute the type of the implicit object parameter for the given function,
/// if any. Returns None if there is no implicit object parameter, and a null
/// QualType if there is a 'matches anything' implicit object parameter.
static Optional<QualType> getImplicitObjectParamType(ASTContext &Context,
const FunctionDecl *F) {
if (!isa<CXXMethodDecl>(F) || isa<CXXConstructorDecl>(F))
return llvm::None;
auto *M = cast<CXXMethodDecl>(F);
// Static member functions' object parameters match all types.
if (M->isStatic())
return QualType();
QualType T = M->getThisObjectType();
if (M->getRefQualifier() == RQ_RValue)
return Context.getRValueReferenceType(T);
return Context.getLValueReferenceType(T);
}
static bool haveSameParameterTypes(ASTContext &Context, const FunctionDecl *F1,
const FunctionDecl *F2, unsigned NumParams) {
if (declaresSameEntity(F1, F2))
return true;
auto NextParam = [&](const FunctionDecl *F, unsigned &I, bool First) {
if (First) {
if (Optional<QualType> T = getImplicitObjectParamType(Context, F))
return *T;
}
assert(I < F->getNumParams());
return F->getParamDecl(I++)->getType();
};
unsigned I1 = 0, I2 = 0;
for (unsigned I = 0; I != NumParams; ++I) {
QualType T1 = NextParam(F1, I1, I == 0);
QualType T2 = NextParam(F2, I2, I == 0);
assert(!T1.isNull() && !T2.isNull() && "Unexpected null param types");
if (!Context.hasSameUnqualifiedType(T1, T2))
return false;
}
return true;
}
/// isBetterOverloadCandidate - Determines whether the first overload
/// candidate is a better candidate than the second (C++ 13.3.3p1).
bool clang::isBetterOverloadCandidate(
Sema &S, const OverloadCandidate &Cand1, const OverloadCandidate &Cand2,
SourceLocation Loc, OverloadCandidateSet::CandidateSetKind Kind) {
// Define viable functions to be better candidates than non-viable
// functions.
if (!Cand2.Viable)
return Cand1.Viable;
else if (!Cand1.Viable)
return false;
// [CUDA] A function with 'never' preference is marked not viable, therefore
// is never shown up here. The worst preference shown up here is 'wrong side',
// e.g. an H function called by a HD function in device compilation. This is
// valid AST as long as the HD function is not emitted, e.g. it is an inline
// function which is called only by an H function. A deferred diagnostic will
// be triggered if it is emitted. However a wrong-sided function is still
// a viable candidate here.
//
// If Cand1 can be emitted and Cand2 cannot be emitted in the current
// context, Cand1 is better than Cand2. If Cand1 can not be emitted and Cand2
// can be emitted, Cand1 is not better than Cand2. This rule should have
// precedence over other rules.
//
// If both Cand1 and Cand2 can be emitted, or neither can be emitted, then
// other rules should be used to determine which is better. This is because
// host/device based overloading resolution is mostly for determining
// viability of a function. If two functions are both viable, other factors
// should take precedence in preference, e.g. the standard-defined preferences
// like argument conversion ranks or enable_if partial-ordering. The
// preference for pass-object-size parameters is probably most similar to a
// type-based-overloading decision and so should take priority.
//
// If other rules cannot determine which is better, CUDA preference will be
// used again to determine which is better.
//
// TODO: Currently IdentifyCUDAPreference does not return correct values
// for functions called in global variable initializers due to missing
// correct context about device/host. Therefore we can only enforce this
// rule when there is a caller. We should enforce this rule for functions
// in global variable initializers once proper context is added.
//
// TODO: We can only enable the hostness based overloading resolution when
// -fgpu-exclude-wrong-side-overloads is on since this requires deferring
// overloading resolution diagnostics.
if (S.getLangOpts().CUDA && Cand1.Function && Cand2.Function &&
S.getLangOpts().GPUExcludeWrongSideOverloads) {
if (FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext)) {
bool IsCallerImplicitHD = Sema::isCUDAImplicitHostDeviceFunction(Caller);
bool IsCand1ImplicitHD =
Sema::isCUDAImplicitHostDeviceFunction(Cand1.Function);
bool IsCand2ImplicitHD =
Sema::isCUDAImplicitHostDeviceFunction(Cand2.Function);
auto P1 = S.IdentifyCUDAPreference(Caller, Cand1.Function);
auto P2 = S.IdentifyCUDAPreference(Caller, Cand2.Function);
assert(P1 != Sema::CFP_Never && P2 != Sema::CFP_Never);
// The implicit HD function may be a function in a system header which
// is forced by pragma. In device compilation, if we prefer HD candidates
// over wrong-sided candidates, overloading resolution may change, which
// may result in non-deferrable diagnostics. As a workaround, we let
// implicit HD candidates take equal preference as wrong-sided candidates.
// This will preserve the overloading resolution.
// TODO: We still need special handling of implicit HD functions since
// they may incur other diagnostics to be deferred. We should make all
// host/device related diagnostics deferrable and remove special handling
// of implicit HD functions.
auto EmitThreshold =
(S.getLangOpts().CUDAIsDevice && IsCallerImplicitHD &&
(IsCand1ImplicitHD || IsCand2ImplicitHD))
? Sema::CFP_Never
: Sema::CFP_WrongSide;
auto Cand1Emittable = P1 > EmitThreshold;
auto Cand2Emittable = P2 > EmitThreshold;
if (Cand1Emittable && !Cand2Emittable)
return true;
if (!Cand1Emittable && Cand2Emittable)
return false;
}
}
// C++ [over.match.best]p1:
//
// -- if F is a static member function, ICS1(F) is defined such
// that ICS1(F) is neither better nor worse than ICS1(G) for
// any function G, and, symmetrically, ICS1(G) is neither
// better nor worse than ICS1(F).
unsigned StartArg = 0;
if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument)
StartArg = 1;
auto IsIllFormedConversion = [&](const ImplicitConversionSequence &ICS) {
// We don't allow incompatible pointer conversions in C++.
if (!S.getLangOpts().CPlusPlus)
return ICS.isStandard() &&
ICS.Standard.Second == ICK_Incompatible_Pointer_Conversion;
// The only ill-formed conversion we allow in C++ is the string literal to
// char* conversion, which is only considered ill-formed after C++11.
return S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings &&
hasDeprecatedStringLiteralToCharPtrConversion(ICS);
};
// Define functions that don't require ill-formed conversions for a given
// argument to be better candidates than functions that do.
unsigned NumArgs = Cand1.Conversions.size();
assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch");
bool HasBetterConversion = false;
for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) {
bool Cand1Bad = IsIllFormedConversion(Cand1.Conversions[ArgIdx]);
bool Cand2Bad = IsIllFormedConversion(Cand2.Conversions[ArgIdx]);
if (Cand1Bad != Cand2Bad) {
if (Cand1Bad)
return false;
HasBetterConversion = true;
}
}
if (HasBetterConversion)
return true;
// C++ [over.match.best]p1:
// A viable function F1 is defined to be a better function than another
// viable function F2 if for all arguments i, ICSi(F1) is not a worse
// conversion sequence than ICSi(F2), and then...
bool HasWorseConversion = false;
for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) {
switch (CompareImplicitConversionSequences(S, Loc,
Cand1.Conversions[ArgIdx],
Cand2.Conversions[ArgIdx])) {
case ImplicitConversionSequence::Better:
// Cand1 has a better conversion sequence.
HasBetterConversion = true;
break;
case ImplicitConversionSequence::Worse:
if (Cand1.Function && Cand2.Function &&
Cand1.isReversed() != Cand2.isReversed() &&
haveSameParameterTypes(S.Context, Cand1.Function, Cand2.Function,
NumArgs)) {
// Work around large-scale breakage caused by considering reversed
// forms of operator== in C++20:
//
// When comparing a function against a reversed function with the same
// parameter types, if we have a better conversion for one argument and
// a worse conversion for the other, the implicit conversion sequences
// are treated as being equally good.
//
// This prevents a comparison function from being considered ambiguous
// with a reversed form that is written in the same way.
//
// We diagnose this as an extension from CreateOverloadedBinOp.
HasWorseConversion = true;
break;
}
// Cand1 can't be better than Cand2.
return false;
case ImplicitConversionSequence::Indistinguishable:
// Do nothing.
break;
}
}
// -- for some argument j, ICSj(F1) is a better conversion sequence than
// ICSj(F2), or, if not that,
if (HasBetterConversion && !HasWorseConversion)
return true;
// -- the context is an initialization by user-defined conversion
// (see 8.5, 13.3.1.5) and the standard conversion sequence
// from the return type of F1 to the destination type (i.e.,
// the type of the entity being initialized) is a better
// conversion sequence than the standard conversion sequence
// from the return type of F2 to the destination type.
if (Kind == OverloadCandidateSet::CSK_InitByUserDefinedConversion &&
Cand1.Function && Cand2.Function &&
isa<CXXConversionDecl>(Cand1.Function) &&
isa<CXXConversionDecl>(Cand2.Function)) {
// First check whether we prefer one of the conversion functions over the
// other. This only distinguishes the results in non-standard, extension
// cases such as the conversion from a lambda closure type to a function
// pointer or block.
ImplicitConversionSequence::CompareKind Result =
compareConversionFunctions(S, Cand1.Function, Cand2.Function);
if (Result == ImplicitConversionSequence::Indistinguishable)
Result = CompareStandardConversionSequences(S, Loc,
Cand1.FinalConversion,
Cand2.FinalConversion);
if (Result != ImplicitConversionSequence::Indistinguishable)
return Result == ImplicitConversionSequence::Better;
// FIXME: Compare kind of reference binding if conversion functions
// convert to a reference type used in direct reference binding, per
// C++14 [over.match.best]p1 section 2 bullet 3.
}
// FIXME: Work around a defect in the C++17 guaranteed copy elision wording,
// as combined with the resolution to CWG issue 243.
//
// When the context is initialization by constructor ([over.match.ctor] or
// either phase of [over.match.list]), a constructor is preferred over
// a conversion function.
if (Kind == OverloadCandidateSet::CSK_InitByConstructor && NumArgs == 1 &&
Cand1.Function && Cand2.Function &&
isa<CXXConstructorDecl>(Cand1.Function) !=
isa<CXXConstructorDecl>(Cand2.Function))
return isa<CXXConstructorDecl>(Cand1.Function);
// -- F1 is a non-template function and F2 is a function template
// specialization, or, if not that,
bool Cand1IsSpecialization = Cand1.Function &&
Cand1.Function->getPrimaryTemplate();
bool Cand2IsSpecialization = Cand2.Function &&
Cand2.Function->getPrimaryTemplate();
if (Cand1IsSpecialization != Cand2IsSpecialization)
return Cand2IsSpecialization;
// -- F1 and F2 are function template specializations, and the function
// template for F1 is more specialized than the template for F2
// according to the partial ordering rules described in 14.5.5.2, or,
// if not that,
if (Cand1IsSpecialization && Cand2IsSpecialization) {
if (FunctionTemplateDecl *BetterTemplate = S.getMoreSpecializedTemplate(
Cand1.Function->getPrimaryTemplate(),
Cand2.Function->getPrimaryTemplate(), Loc,
isa<CXXConversionDecl>(Cand1.Function) ? TPOC_Conversion
: TPOC_Call,
Cand1.ExplicitCallArguments, Cand2.ExplicitCallArguments,
Cand1.isReversed() ^ Cand2.isReversed()))
return BetterTemplate == Cand1.Function->getPrimaryTemplate();
}
// -— F1 and F2 are non-template functions with the same
// parameter-type-lists, and F1 is more constrained than F2 [...],
if (Cand1.Function && Cand2.Function && !Cand1IsSpecialization &&
!Cand2IsSpecialization && Cand1.Function->hasPrototype() &&
Cand2.Function->hasPrototype()) {
auto *PT1 = cast<FunctionProtoType>(Cand1.Function->getFunctionType());
auto *PT2 = cast<FunctionProtoType>(Cand2.Function->getFunctionType());
if (PT1->getNumParams() == PT2->getNumParams() &&
PT1->isVariadic() == PT2->isVariadic() &&
S.FunctionParamTypesAreEqual(PT1, PT2)) {
Expr *RC1 = Cand1.Function->getTrailingRequiresClause();
Expr *RC2 = Cand2.Function->getTrailingRequiresClause();
if (RC1 && RC2) {
bool AtLeastAsConstrained1, AtLeastAsConstrained2;
if (S.IsAtLeastAsConstrained(Cand1.Function, {RC1}, Cand2.Function,
{RC2}, AtLeastAsConstrained1) ||
S.IsAtLeastAsConstrained(Cand2.Function, {RC2}, Cand1.Function,
{RC1}, AtLeastAsConstrained2))
return false;
if (AtLeastAsConstrained1 != AtLeastAsConstrained2)
return AtLeastAsConstrained1;
} else if (RC1 || RC2) {
return RC1 != nullptr;
}
}
}
// -- F1 is a constructor for a class D, F2 is a constructor for a base
// class B of D, and for all arguments the corresponding parameters of
// F1 and F2 have the same type.
// FIXME: Implement the "all parameters have the same type" check.
bool Cand1IsInherited =
dyn_cast_or_null<ConstructorUsingShadowDecl>(Cand1.FoundDecl.getDecl());
bool Cand2IsInherited =
dyn_cast_or_null<ConstructorUsingShadowDecl>(Cand2.FoundDecl.getDecl());
if (Cand1IsInherited != Cand2IsInherited)
return Cand2IsInherited;
else if (Cand1IsInherited) {
assert(Cand2IsInherited);
auto *Cand1Class = cast<CXXRecordDecl>(Cand1.Function->getDeclContext());
auto *Cand2Class = cast<CXXRecordDecl>(Cand2.Function->getDeclContext());
if (Cand1Class->isDerivedFrom(Cand2Class))
return true;
if (Cand2Class->isDerivedFrom(Cand1Class))
return false;
// Inherited from sibling base classes: still ambiguous.
}
// -- F2 is a rewritten candidate (12.4.1.2) and F1 is not
// -- F1 and F2 are rewritten candidates, and F2 is a synthesized candidate
// with reversed order of parameters and F1 is not
//
// We rank reversed + different operator as worse than just reversed, but
// that comparison can never happen, because we only consider reversing for
// the maximally-rewritten operator (== or <=>).
if (Cand1.RewriteKind != Cand2.RewriteKind)
return Cand1.RewriteKind < Cand2.RewriteKind;
// Check C++17 tie-breakers for deduction guides.
{
auto *Guide1 = dyn_cast_or_null<CXXDeductionGuideDecl>(Cand1.Function);
auto *Guide2 = dyn_cast_or_null<CXXDeductionGuideDecl>(Cand2.Function);
if (Guide1 && Guide2) {
// -- F1 is generated from a deduction-guide and F2 is not
if (Guide1->isImplicit() != Guide2->isImplicit())
return Guide2->isImplicit();
// -- F1 is the copy deduction candidate(16.3.1.8) and F2 is not
if (Guide1->isCopyDeductionCandidate())
return true;
}
}
// Check for enable_if value-based overload resolution.
if (Cand1.Function && Cand2.Function) {
Comparison Cmp = compareEnableIfAttrs(S, Cand1.Function, Cand2.Function);
if (Cmp != Comparison::Equal)
return Cmp == Comparison::Better;
}
bool HasPS1 = Cand1.Function != nullptr &&
functionHasPassObjectSizeParams(Cand1.Function);
bool HasPS2 = Cand2.Function != nullptr &&
functionHasPassObjectSizeParams(Cand2.Function);
if (HasPS1 != HasPS2 && HasPS1)
return true;
auto MV = isBetterMultiversionCandidate(Cand1, Cand2);
if (MV == Comparison::Better)
return true;
if (MV == Comparison::Worse)
return false;
// If other rules cannot determine which is better, CUDA preference is used
// to determine which is better.
if (S.getLangOpts().CUDA && Cand1.Function && Cand2.Function) {
FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext);
return S.IdentifyCUDAPreference(Caller, Cand1.Function) >
S.IdentifyCUDAPreference(Caller, Cand2.Function);
}
// General member function overloading is handled above, so this only handles
// constructors with address spaces.
// This only handles address spaces since C++ has no other
// qualifier that can be used with constructors.
const auto *CD1 = dyn_cast_or_null<CXXConstructorDecl>(Cand1.Function);
const auto *CD2 = dyn_cast_or_null<CXXConstructorDecl>(Cand2.Function);
if (CD1 && CD2) {
LangAS AS1 = CD1->getMethodQualifiers().getAddressSpace();
LangAS AS2 = CD2->getMethodQualifiers().getAddressSpace();
if (AS1 != AS2) {
if (Qualifiers::isAddressSpaceSupersetOf(AS2, AS1))
return true;
if (Qualifiers::isAddressSpaceSupersetOf(AS2, AS1))
return false;
}
}
return false;
}
/// Determine whether two declarations are "equivalent" for the purposes of
/// name lookup and overload resolution. This applies when the same internal/no
/// linkage entity is defined by two modules (probably by textually including
/// the same header). In such a case, we don't consider the declarations to
/// declare the same entity, but we also don't want lookups with both
/// declarations visible to be ambiguous in some cases (this happens when using
/// a modularized libstdc++).
bool Sema::isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
const NamedDecl *B) {
auto *VA = dyn_cast_or_null<ValueDecl>(A);
auto *VB = dyn_cast_or_null<ValueDecl>(B);
if (!VA || !VB)
return false;
// The declarations must be declaring the same name as an internal linkage
// entity in different modules.
if (!VA->getDeclContext()->getRedeclContext()->Equals(
VB->getDeclContext()->getRedeclContext()) ||
getOwningModule(VA) == getOwningModule(VB) ||
VA->isExternallyVisible() || VB->isExternallyVisible())
return false;
// Check that the declarations appear to be equivalent.
//
// FIXME: Checking the type isn't really enough to resolve the ambiguity.
// For constants and functions, we should check the initializer or body is
// the same. For non-constant variables, we shouldn't allow it at all.
if (Context.hasSameType(VA->getType(), VB->getType()))
return true;
// Enum constants within unnamed enumerations will have different types, but
// may still be similar enough to be interchangeable for our purposes.
if (auto *EA = dyn_cast<EnumConstantDecl>(VA)) {
if (auto *EB = dyn_cast<EnumConstantDecl>(VB)) {
// Only handle anonymous enums. If the enumerations were named and
// equivalent, they would have been merged to the same type.
auto *EnumA = cast<EnumDecl>(EA->getDeclContext());
auto *EnumB = cast<EnumDecl>(EB->getDeclContext());
if (EnumA->hasNameForLinkage() || EnumB->hasNameForLinkage() ||
!Context.hasSameType(EnumA->getIntegerType(),
EnumB->getIntegerType()))
return false;
// Allow this only if the value is the same for both enumerators.
return llvm::APSInt::isSameValue(EA->getInitVal(), EB->getInitVal());
}
}
// Nothing else is sufficiently similar.
return false;
}
void Sema::diagnoseEquivalentInternalLinkageDeclarations(
SourceLocation Loc, const NamedDecl *D, ArrayRef<const NamedDecl *> Equiv) {
assert(D && "Unknown declaration");
Diag(Loc, diag::ext_equivalent_internal_linkage_decl_in_modules) << D;
Module *M = getOwningModule(D);
Diag(D->getLocation(), diag::note_equivalent_internal_linkage_decl)
<< !M << (M ? M->getFullModuleName() : "");
for (auto *E : Equiv) {
Module *M = getOwningModule(E);
Diag(E->getLocation(), diag::note_equivalent_internal_linkage_decl)
<< !M << (M ? M->getFullModuleName() : "");
}
}
/// Computes the best viable function (C++ 13.3.3)
/// within an overload candidate set.
///
/// \param Loc The location of the function name (or operator symbol) for
/// which overload resolution occurs.
///
/// \param Best If overload resolution was successful or found a deleted
/// function, \p Best points to the candidate function found.
///
/// \returns The result of overload resolution.
OverloadingResult
OverloadCandidateSet::BestViableFunction(Sema &S, SourceLocation Loc,
iterator &Best) {
llvm::SmallVector<OverloadCandidate *, 16> Candidates;
std::transform(begin(), end(), std::back_inserter(Candidates),
[](OverloadCandidate &Cand) { return &Cand; });
// [CUDA] HD->H or HD->D calls are technically not allowed by CUDA but
// are accepted by both clang and NVCC. However, during a particular
// compilation mode only one call variant is viable. We need to
// exclude non-viable overload candidates from consideration based
// only on their host/device attributes. Specifically, if one
// candidate call is WrongSide and the other is SameSide, we ignore
// the WrongSide candidate.
// We only need to remove wrong-sided candidates here if
// -fgpu-exclude-wrong-side-overloads is off. When
// -fgpu-exclude-wrong-side-overloads is on, all candidates are compared
// uniformly in isBetterOverloadCandidate.
if (S.getLangOpts().CUDA && !S.getLangOpts().GPUExcludeWrongSideOverloads) {
const FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext);
bool ContainsSameSideCandidate =
llvm::any_of(Candidates, [&](OverloadCandidate *Cand) {
// Check viable function only.
return Cand->Viable && Cand->Function &&
S.IdentifyCUDAPreference(Caller, Cand->Function) ==
Sema::CFP_SameSide;
});
if (ContainsSameSideCandidate) {
auto IsWrongSideCandidate = [&](OverloadCandidate *Cand) {
// Check viable function only to avoid unnecessary data copying/moving.
return Cand->Viable && Cand->Function &&
S.IdentifyCUDAPreference(Caller, Cand->Function) ==
Sema::CFP_WrongSide;
};
llvm::erase_if(Candidates, IsWrongSideCandidate);
}
}
// Find the best viable function.
Best = end();
for (auto *Cand : Candidates) {
Cand->Best = false;
if (Cand->Viable)
if (Best == end() ||
isBetterOverloadCandidate(S, *Cand, *Best, Loc, Kind))
Best = Cand;
}
// If we didn't find any viable functions, abort.
if (Best == end())
return OR_No_Viable_Function;
llvm::SmallVector<const NamedDecl *, 4> EquivalentCands;
llvm::SmallVector<OverloadCandidate*, 4> PendingBest;
PendingBest.push_back(&*Best);
Best->Best = true;
// Make sure that this function is better than every other viable
// function. If not, we have an ambiguity.
while (!PendingBest.empty()) {
auto *Curr = PendingBest.pop_back_val();
for (auto *Cand : Candidates) {
if (Cand->Viable && !Cand->Best &&
!isBetterOverloadCandidate(S, *Curr, *Cand, Loc, Kind)) {
PendingBest.push_back(Cand);
Cand->Best = true;
if (S.isEquivalentInternalLinkageDeclaration(Cand->Function,
Curr->Function))
EquivalentCands.push_back(Cand->Function);
else
Best = end();
}
}
}
// If we found more than one best candidate, this is ambiguous.
if (Best == end())
return OR_Ambiguous;
// Best is the best viable function.
if (Best->Function && Best->Function->isDeleted())
return OR_Deleted;
if (!EquivalentCands.empty())
S.diagnoseEquivalentInternalLinkageDeclarations(Loc, Best->Function,
EquivalentCands);
return OR_Success;
}
namespace {
enum OverloadCandidateKind {
oc_function,
oc_method,
oc_reversed_binary_operator,
oc_constructor,
oc_implicit_default_constructor,
oc_implicit_copy_constructor,
oc_implicit_move_constructor,
oc_implicit_copy_assignment,
oc_implicit_move_assignment,
oc_implicit_equality_comparison,
oc_inherited_constructor
};
enum OverloadCandidateSelect {
ocs_non_template,
ocs_template,
ocs_described_template,
};
static std::pair<OverloadCandidateKind, OverloadCandidateSelect>
ClassifyOverloadCandidate(Sema &S, NamedDecl *Found, FunctionDecl *Fn,
OverloadCandidateRewriteKind CRK,
std::string &Description) {
bool isTemplate = Fn->isTemplateDecl() || Found->isTemplateDecl();
if (FunctionTemplateDecl *FunTmpl = Fn->getPrimaryTemplate()) {
isTemplate = true;
Description = S.getTemplateArgumentBindingsText(
FunTmpl->getTemplateParameters(), *Fn->getTemplateSpecializationArgs());
}
OverloadCandidateSelect Select = [&]() {
if (!Description.empty())
return ocs_described_template;
return isTemplate ? ocs_template : ocs_non_template;
}();
OverloadCandidateKind Kind = [&]() {
if (Fn->isImplicit() && Fn->getOverloadedOperator() == OO_EqualEqual)
return oc_implicit_equality_comparison;
if (CRK & CRK_Reversed)
return oc_reversed_binary_operator;
if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Fn)) {
if (!Ctor->isImplicit()) {
if (isa<ConstructorUsingShadowDecl>(Found))
return oc_inherited_constructor;
else
return oc_constructor;
}
if (Ctor->isDefaultConstructor())
return oc_implicit_default_constructor;
if (Ctor->isMoveConstructor())
return oc_implicit_move_constructor;
assert(Ctor->isCopyConstructor() &&
"unexpected sort of implicit constructor");
return oc_implicit_copy_constructor;
}
if (CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Fn)) {
// This actually gets spelled 'candidate function' for now, but
// it doesn't hurt to split it out.
if (!Meth->isImplicit())
return oc_method;
if (Meth->isMoveAssignmentOperator())
return oc_implicit_move_assignment;
if (Meth->isCopyAssignmentOperator())
return oc_implicit_copy_assignment;
assert(isa<CXXConversionDecl>(Meth) && "expected conversion");
return oc_method;
}
return oc_function;
}();
return std::make_pair(Kind, Select);
}
void MaybeEmitInheritedConstructorNote(Sema &S, Decl *FoundDecl) {
// FIXME: It'd be nice to only emit a note once per using-decl per overload
// set.
if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(FoundDecl))
S.Diag(FoundDecl->getLocation(),
diag::note_ovl_candidate_inherited_constructor)
<< Shadow->getNominatedBaseClass();
}
} // end anonymous namespace
static bool isFunctionAlwaysEnabled(const ASTContext &Ctx,
const FunctionDecl *FD) {
for (auto *EnableIf : FD->specific_attrs<EnableIfAttr>()) {
bool AlwaysTrue;
if (EnableIf->getCond()->isValueDependent() ||
!EnableIf->getCond()->EvaluateAsBooleanCondition(AlwaysTrue, Ctx))
return false;
if (!AlwaysTrue)
return false;
}
return true;
}
/// Returns true if we can take the address of the function.
///
/// \param Complain - If true, we'll emit a diagnostic
/// \param InOverloadResolution - For the purposes of emitting a diagnostic, are
/// we in overload resolution?
/// \param Loc - The location of the statement we're complaining about. Ignored
/// if we're not complaining, or if we're in overload resolution.
static bool checkAddressOfFunctionIsAvailable(Sema &S, const FunctionDecl *FD,
bool Complain,
bool InOverloadResolution,
SourceLocation Loc) {
if (!isFunctionAlwaysEnabled(S.Context, FD)) {
if (Complain) {
if (InOverloadResolution)
S.Diag(FD->getBeginLoc(),
diag::note_addrof_ovl_candidate_disabled_by_enable_if_attr);
else
S.Diag(Loc, diag::err_addrof_function_disabled_by_enable_if_attr) << FD;
}
return false;
}
if (FD->getTrailingRequiresClause()) {
ConstraintSatisfaction Satisfaction;
if (S.CheckFunctionConstraints(FD, Satisfaction, Loc))
return false;
if (!Satisfaction.IsSatisfied) {
if (Complain) {
if (InOverloadResolution)
S.Diag(FD->getBeginLoc(),
diag::note_ovl_candidate_unsatisfied_constraints);
else
S.Diag(Loc, diag::err_addrof_function_constraints_not_satisfied)
<< FD;
S.DiagnoseUnsatisfiedConstraint(Satisfaction);
}
return false;
}
}
auto I = llvm::find_if(FD->parameters(), [](const ParmVarDecl *P) {
return P->hasAttr<PassObjectSizeAttr>();
});
if (I == FD->param_end())
return true;
if (Complain) {
// Add one to ParamNo because it's user-facing
unsigned ParamNo = std::distance(FD->param_begin(), I) + 1;
if (InOverloadResolution)
S.Diag(FD->getLocation(),
diag::note_ovl_candidate_has_pass_object_size_params)
<< ParamNo;
else
S.Diag(Loc, diag::err_address_of_function_with_pass_object_size_params)
<< FD << ParamNo;
}
return false;
}
static bool checkAddressOfCandidateIsAvailable(Sema &S,
const FunctionDecl *FD) {
return checkAddressOfFunctionIsAvailable(S, FD, /*Complain=*/true,
/*InOverloadResolution=*/true,
/*Loc=*/SourceLocation());
}
bool Sema::checkAddressOfFunctionIsAvailable(const FunctionDecl *Function,
bool Complain,
SourceLocation Loc) {
return ::checkAddressOfFunctionIsAvailable(*this, Function, Complain,
/*InOverloadResolution=*/false,
Loc);
}
// Don't print candidates other than the one that matches the calling
// convention of the call operator, since that is guaranteed to exist.
static bool shouldSkipNotingLambdaConversionDecl(FunctionDecl *Fn) {
const auto *ConvD = dyn_cast<CXXConversionDecl>(Fn);
if (!ConvD)
return false;
const auto *RD = cast<CXXRecordDecl>(Fn->getParent());
if (!RD->isLambda())
return false;
CXXMethodDecl *CallOp = RD->getLambdaCallOperator();
CallingConv CallOpCC =
CallOp->getType()->castAs<FunctionType>()->getCallConv();
QualType ConvRTy = ConvD->getType()->castAs<FunctionType>()->getReturnType();
CallingConv ConvToCC =
ConvRTy->getPointeeType()->castAs<FunctionType>()->getCallConv();
return ConvToCC != CallOpCC;
}
// Notes the location of an overload candidate.
void Sema::NoteOverloadCandidate(NamedDecl *Found, FunctionDecl *Fn,
OverloadCandidateRewriteKind RewriteKind,
QualType DestType, bool TakingAddress) {
if (TakingAddress && !checkAddressOfCandidateIsAvailable(*this, Fn))
return;
if (Fn->isMultiVersion() && Fn->hasAttr<TargetAttr>() &&
!Fn->getAttr<TargetAttr>()->isDefaultVersion())
return;
if (shouldSkipNotingLambdaConversionDecl(Fn))
return;
std::string FnDesc;
std::pair<OverloadCandidateKind, OverloadCandidateSelect> KSPair =
ClassifyOverloadCandidate(*this, Found, Fn, RewriteKind, FnDesc);
PartialDiagnostic PD = PDiag(diag::note_ovl_candidate)
<< (unsigned)KSPair.first << (unsigned)KSPair.second
<< Fn << FnDesc;
HandleFunctionTypeMismatch(PD, Fn->getType(), DestType);
Diag(Fn->getLocation(), PD);
MaybeEmitInheritedConstructorNote(*this, Found);
}
static void
MaybeDiagnoseAmbiguousConstraints(Sema &S, ArrayRef<OverloadCandidate> Cands) {
// Perhaps the ambiguity was caused by two atomic constraints that are
// 'identical' but not equivalent:
//
// void foo() requires (sizeof(T) > 4) { } // #1
// void foo() requires (sizeof(T) > 4) && T::value { } // #2
//
// The 'sizeof(T) > 4' constraints are seemingly equivalent and should cause
// #2 to subsume #1, but these constraint are not considered equivalent
// according to the subsumption rules because they are not the same
// source-level construct. This behavior is quite confusing and we should try
// to help the user figure out what happened.
SmallVector<const Expr *, 3> FirstAC, SecondAC;
FunctionDecl *FirstCand = nullptr, *SecondCand = nullptr;
for (auto I = Cands.begin(), E = Cands.end(); I != E; ++I) {
if (!I->Function)
continue;
SmallVector<const Expr *, 3> AC;
if (auto *Template = I->Function->getPrimaryTemplate())
Template->getAssociatedConstraints(AC);
else
I->Function->getAssociatedConstraints(AC);
if (AC.empty())
continue;
if (FirstCand == nullptr) {
FirstCand = I->Function;
FirstAC = AC;
} else if (SecondCand == nullptr) {
SecondCand = I->Function;
SecondAC = AC;
} else {
// We have more than one pair of constrained functions - this check is
// expensive and we'd rather not try to diagnose it.
return;
}
}
if (!SecondCand)
return;
// The diagnostic can only happen if there are associated constraints on
// both sides (there needs to be some identical atomic constraint).
if (S.MaybeEmitAmbiguousAtomicConstraintsDiagnostic(FirstCand, FirstAC,
SecondCand, SecondAC))
// Just show the user one diagnostic, they'll probably figure it out
// from here.
return;
}
// Notes the location of all overload candidates designated through
// OverloadedExpr
void Sema::NoteAllOverloadCandidates(Expr *OverloadedExpr, QualType DestType,
bool TakingAddress) {
assert(OverloadedExpr->getType() == Context.OverloadTy);
OverloadExpr::FindResult Ovl = OverloadExpr::find(OverloadedExpr);
OverloadExpr *OvlExpr = Ovl.Expression;
for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
IEnd = OvlExpr->decls_end();
I != IEnd; ++I) {
if (FunctionTemplateDecl *FunTmpl =
dyn_cast<FunctionTemplateDecl>((*I)->getUnderlyingDecl()) ) {
NoteOverloadCandidate(*I, FunTmpl->getTemplatedDecl(), CRK_None, DestType,
TakingAddress);
} else if (FunctionDecl *Fun
= dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl()) ) {
NoteOverloadCandidate(*I, Fun, CRK_None, DestType, TakingAddress);
}
}
}
/// Diagnoses an ambiguous conversion. The partial diagnostic is the
/// "lead" diagnostic; it will be given two arguments, the source and
/// target types of the conversion.
void ImplicitConversionSequence::DiagnoseAmbiguousConversion(
Sema &S,
SourceLocation CaretLoc,
const PartialDiagnostic &PDiag) const {
S.Diag(CaretLoc, PDiag)
<< Ambiguous.getFromType() << Ambiguous.getToType();
unsigned CandsShown = 0;
AmbiguousConversionSequence::const_iterator I, E;
for (I = Ambiguous.begin(), E = Ambiguous.end(); I != E; ++I) {
if (CandsShown >= S.Diags.getNumOverloadCandidatesToShow())
break;
++CandsShown;
S.NoteOverloadCandidate(I->first, I->second);
}
S.Diags.overloadCandidatesShown(CandsShown);
if (I != E)
S.Diag(SourceLocation(), diag::note_ovl_too_many_candidates) << int(E - I);
}
static void DiagnoseBadConversion(Sema &S, OverloadCandidate *Cand,
unsigned I, bool TakingCandidateAddress) {
const ImplicitConversionSequence &Conv = Cand->Conversions[I];
assert(Conv.isBad());
assert(Cand->Function && "for now, candidate must be a function");
FunctionDecl *Fn = Cand->Function;
// There's a conversion slot for the object argument if this is a
// non-constructor method. Note that 'I' corresponds the
// conversion-slot index.
bool isObjectArgument = false;
if (isa<CXXMethodDecl>(Fn) && !isa<CXXConstructorDecl>(Fn)) {
if (I == 0)
isObjectArgument = true;
else
I--;
}
std::string FnDesc;
std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn, Cand->getRewriteKind(),
FnDesc);
Expr *FromExpr = Conv.Bad.FromExpr;
QualType FromTy = Conv.Bad.getFromType();
QualType ToTy = Conv.Bad.getToType();
if (FromTy == S.Context.OverloadTy) {
assert(FromExpr && "overload set argument came from implicit argument?");
Expr *E = FromExpr->IgnoreParens();
if (isa<UnaryOperator>(E))
E = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens();
DeclarationName Name = cast<OverloadExpr>(E)->getName();
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_overload)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
<< (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << ToTy
<< Name << I + 1;
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
// Do some hand-waving analysis to see if the non-viability is due
// to a qualifier mismatch.
CanQualType CFromTy = S.Context.getCanonicalType(FromTy);
CanQualType CToTy = S.Context.getCanonicalType(ToTy);
if (CanQual<ReferenceType> RT = CToTy->getAs<ReferenceType>())
CToTy = RT->getPointeeType();
else {
// TODO: detect and diagnose the full richness of const mismatches.
if (CanQual<PointerType> FromPT = CFromTy->getAs<PointerType>())
if (CanQual<PointerType> ToPT = CToTy->getAs<PointerType>()) {
CFromTy = FromPT->getPointeeType();
CToTy = ToPT->getPointeeType();
}
}
if (CToTy.getUnqualifiedType() == CFromTy.getUnqualifiedType() &&
!CToTy.isAtLeastAsQualifiedAs(CFromTy)) {
Qualifiers FromQs = CFromTy.getQualifiers();
Qualifiers ToQs = CToTy.getQualifiers();
if (FromQs.getAddressSpace() != ToQs.getAddressSpace()) {
if (isObjectArgument)
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace_this)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
<< FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
<< FromQs.getAddressSpace() << ToQs.getAddressSpace();
else
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
<< FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
<< FromQs.getAddressSpace() << ToQs.getAddressSpace()
<< ToTy->isReferenceType() << I + 1;
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) {
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_ownership)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
<< (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
<< FromQs.getObjCLifetime() << ToQs.getObjCLifetime()
<< (unsigned)isObjectArgument << I + 1;
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
if (FromQs.getObjCGCAttr() != ToQs.getObjCGCAttr()) {
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_gc)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
<< (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
<< FromQs.getObjCGCAttr() << ToQs.getObjCGCAttr()
<< (unsigned)isObjectArgument << I + 1;
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
if (FromQs.hasUnaligned() != ToQs.hasUnaligned()) {
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_unaligned)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
<< (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
<< FromQs.hasUnaligned() << I + 1;
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
assert(CVR && "expected qualifiers mismatch");
if (isObjectArgument) {
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr_this)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
<< (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
<< (CVR - 1);
} else {
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
<< (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
<< (CVR - 1) << I + 1;
}
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
if (Conv.Bad.Kind == BadConversionSequence::lvalue_ref_to_rvalue ||
Conv.Bad.Kind == BadConversionSequence::rvalue_ref_to_lvalue) {
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_value_category)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
<< (unsigned)isObjectArgument << I + 1
<< (Conv.Bad.Kind == BadConversionSequence::rvalue_ref_to_lvalue)
<< (FromExpr ? FromExpr->getSourceRange() : SourceRange());
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
// Special diagnostic for failure to convert an initializer list, since
// telling the user that it has type void is not useful.
if (FromExpr && isa<InitListExpr>(FromExpr)) {
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_list_argument)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
<< (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
<< ToTy << (unsigned)isObjectArgument << I + 1
<< (Conv.Bad.Kind == BadConversionSequence::too_few_initializers ? 1
: Conv.Bad.Kind == BadConversionSequence::too_many_initializers
? 2
: 0);
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
// Diagnose references or pointers to incomplete types differently,
// since it's far from impossible that the incompleteness triggered
// the failure.
QualType TempFromTy = FromTy.getNonReferenceType();
if (const PointerType *PTy = TempFromTy->getAs<PointerType>())
TempFromTy = PTy->getPointeeType();
if (TempFromTy->isIncompleteType()) {
// Emit the generic diagnostic and, optionally, add the hints to it.
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv_incomplete)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
<< (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
<< ToTy << (unsigned)isObjectArgument << I + 1
<< (unsigned)(Cand->Fix.Kind);
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
// Diagnose base -> derived pointer conversions.
unsigned BaseToDerivedConversion = 0;
if (const PointerType *FromPtrTy = FromTy->getAs<PointerType>()) {
if (const PointerType *ToPtrTy = ToTy->getAs<PointerType>()) {
if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs(
FromPtrTy->getPointeeType()) &&
!FromPtrTy->getPointeeType()->isIncompleteType() &&
!ToPtrTy->getPointeeType()->isIncompleteType() &&
S.IsDerivedFrom(SourceLocation(), ToPtrTy->getPointeeType(),
FromPtrTy->getPointeeType()))
BaseToDerivedConversion = 1;
}
} else if (const ObjCObjectPointerType *FromPtrTy
= FromTy->getAs<ObjCObjectPointerType>()) {
if (const ObjCObjectPointerType *ToPtrTy
= ToTy->getAs<ObjCObjectPointerType>())
if (const ObjCInterfaceDecl *FromIface = FromPtrTy->getInterfaceDecl())
if (const ObjCInterfaceDecl *ToIface = ToPtrTy->getInterfaceDecl())
if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs(
FromPtrTy->getPointeeType()) &&
FromIface->isSuperClassOf(ToIface))
BaseToDerivedConversion = 2;
} else if (const ReferenceType *ToRefTy = ToTy->getAs<ReferenceType>()) {
if (ToRefTy->getPointeeType().isAtLeastAsQualifiedAs(FromTy) &&
!FromTy->isIncompleteType() &&
!ToRefTy->getPointeeType()->isIncompleteType() &&
S.IsDerivedFrom(SourceLocation(), ToRefTy->getPointeeType(), FromTy)) {
BaseToDerivedConversion = 3;
}
}
if (BaseToDerivedConversion) {
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_base_to_derived_conv)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
<< (FromExpr ? FromExpr->getSourceRange() : SourceRange())
<< (BaseToDerivedConversion - 1) << FromTy << ToTy << I + 1;
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
if (isa<ObjCObjectPointerType>(CFromTy) &&
isa<PointerType>(CToTy)) {
Qualifiers FromQs = CFromTy.getQualifiers();
Qualifiers ToQs = CToTy.getQualifiers();
if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) {
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_arc_conv)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
<< FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
<< FromTy << ToTy << (unsigned)isObjectArgument << I + 1;
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
}
if (TakingCandidateAddress &&
!checkAddressOfCandidateIsAvailable(S, Cand->Function))
return;
// Emit the generic diagnostic and, optionally, add the hints to it.
PartialDiagnostic FDiag = S.PDiag(diag::note_ovl_candidate_bad_conv);
FDiag << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
<< (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
<< ToTy << (unsigned)isObjectArgument << I + 1
<< (unsigned)(Cand->Fix.Kind);
// If we can fix the conversion, suggest the FixIts.
for (std::vector<FixItHint>::iterator HI = Cand->Fix.Hints.begin(),
HE = Cand->Fix.Hints.end(); HI != HE; ++HI)
FDiag << *HI;
S.Diag(Fn->getLocation(), FDiag);
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
}
/// Additional arity mismatch diagnosis specific to a function overload
/// candidates. This is not covered by the more general DiagnoseArityMismatch()
/// over a candidate in any candidate set.
static bool CheckArityMismatch(Sema &S, OverloadCandidate *Cand,
unsigned NumArgs) {
FunctionDecl *Fn = Cand->Function;
unsigned MinParams = Fn->getMinRequiredArguments();
// With invalid overloaded operators, it's possible that we think we
// have an arity mismatch when in fact it looks like we have the
// right number of arguments, because only overloaded operators have
// the weird behavior of overloading member and non-member functions.
// Just don't report anything.
if (Fn->isInvalidDecl() &&
Fn->getDeclName().getNameKind() == DeclarationName::CXXOperatorName)
return true;
if (NumArgs < MinParams) {
assert((Cand->FailureKind == ovl_fail_too_few_arguments) ||
(Cand->FailureKind == ovl_fail_bad_deduction &&
Cand->DeductionFailure.Result == Sema::TDK_TooFewArguments));
} else {
assert((Cand->FailureKind == ovl_fail_too_many_arguments) ||
(Cand->FailureKind == ovl_fail_bad_deduction &&
Cand->DeductionFailure.Result == Sema::TDK_TooManyArguments));
}
return false;
}
/// General arity mismatch diagnosis over a candidate in a candidate set.
static void DiagnoseArityMismatch(Sema &S, NamedDecl *Found, Decl *D,
unsigned NumFormalArgs) {
assert(isa<FunctionDecl>(D) &&
"The templated declaration should at least be a function"
" when diagnosing bad template argument deduction due to too many"
" or too few arguments");
FunctionDecl *Fn = cast<FunctionDecl>(D);
// TODO: treat calls to a missing default constructor as a special case
const auto *FnTy = Fn->getType()->castAs<FunctionProtoType>();
unsigned MinParams = Fn->getMinRequiredArguments();
// at least / at most / exactly
unsigned mode, modeCount;
if (NumFormalArgs < MinParams) {
if (MinParams != FnTy->getNumParams() || FnTy->isVariadic() ||
FnTy->isTemplateVariadic())
mode = 0; // "at least"
else
mode = 2; // "exactly"
modeCount = MinParams;
} else {
if (MinParams != FnTy->getNumParams())
mode = 1; // "at most"
else
mode = 2; // "exactly"
modeCount = FnTy->getNumParams();
}
std::string Description;
std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
ClassifyOverloadCandidate(S, Found, Fn, CRK_None, Description);
if (modeCount == 1 && Fn->getParamDecl(0)->getDeclName())
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity_one)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
<< Description << mode << Fn->getParamDecl(0) << NumFormalArgs;
else
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
<< Description << mode << modeCount << NumFormalArgs;
MaybeEmitInheritedConstructorNote(S, Found);
}
/// Arity mismatch diagnosis specific to a function overload candidate.
static void DiagnoseArityMismatch(Sema &S, OverloadCandidate *Cand,
unsigned NumFormalArgs) {
if (!CheckArityMismatch(S, Cand, NumFormalArgs))
DiagnoseArityMismatch(S, Cand->FoundDecl, Cand->Function, NumFormalArgs);
}
static TemplateDecl *getDescribedTemplate(Decl *Templated) {
if (TemplateDecl *TD = Templated->getDescribedTemplate())
return TD;
llvm_unreachable("Unsupported: Getting the described template declaration"
" for bad deduction diagnosis");
}
/// Diagnose a failed template-argument deduction.
static void DiagnoseBadDeduction(Sema &S, NamedDecl *Found, Decl *Templated,
DeductionFailureInfo &DeductionFailure,
unsigned NumArgs,
bool TakingCandidateAddress) {
TemplateParameter Param = DeductionFailure.getTemplateParameter();
NamedDecl *ParamD;
(ParamD = Param.dyn_cast<TemplateTypeParmDecl*>()) ||
(ParamD = Param.dyn_cast<NonTypeTemplateParmDecl*>()) ||
(ParamD = Param.dyn_cast<TemplateTemplateParmDecl*>());
switch (DeductionFailure.Result) {
case Sema::TDK_Success:
llvm_unreachable("TDK_success while diagnosing bad deduction");
case Sema::TDK_Incomplete: {
assert(ParamD && "no parameter found for incomplete deduction result");
S.Diag(Templated->getLocation(),
diag::note_ovl_candidate_incomplete_deduction)
<< ParamD->getDeclName();
MaybeEmitInheritedConstructorNote(S, Found);
return;
}
case Sema::TDK_IncompletePack: {
assert(ParamD && "no parameter found for incomplete deduction result");
S.Diag(Templated->getLocation(),
diag::note_ovl_candidate_incomplete_deduction_pack)
<< ParamD->getDeclName()
<< (DeductionFailure.getFirstArg()->pack_size() + 1)
<< *DeductionFailure.getFirstArg();
MaybeEmitInheritedConstructorNote(S, Found);
return;
}
case Sema::TDK_Underqualified: {
assert(ParamD && "no parameter found for bad qualifiers deduction result");
TemplateTypeParmDecl *TParam = cast<TemplateTypeParmDecl>(ParamD);
QualType Param = DeductionFailure.getFirstArg()->getAsType();
// Param will have been canonicalized, but it should just be a
// qualified version of ParamD, so move the qualifiers to that.
QualifierCollector Qs;
Qs.strip(Param);
QualType NonCanonParam = Qs.apply(S.Context, TParam->getTypeForDecl());
assert(S.Context.hasSameType(Param, NonCanonParam));
// Arg has also been canonicalized, but there's nothing we can do
// about that. It also doesn't matter as much, because it won't
// have any template parameters in it (because deduction isn't
// done on dependent types).
QualType Arg = DeductionFailure.getSecondArg()->getAsType();
S.Diag(Templated->getLocation(), diag::note_ovl_candidate_underqualified)
<< ParamD->getDeclName() << Arg << NonCanonParam;
MaybeEmitInheritedConstructorNote(S, Found);
return;
}
case Sema::TDK_Inconsistent: {
assert(ParamD && "no parameter found for inconsistent deduction result");
int which = 0;
if (isa<TemplateTypeParmDecl>(ParamD))
which = 0;
else if (isa<NonTypeTemplateParmDecl>(ParamD)) {
// Deduction might have failed because we deduced arguments of two
// different types for a non-type template parameter.
// FIXME: Use a different TDK value for this.
QualType T1 =
DeductionFailure.getFirstArg()->getNonTypeTemplateArgumentType();
QualType T2 =
DeductionFailure.getSecondArg()->getNonTypeTemplateArgumentType();
if (!T1.isNull() && !T2.isNull() && !S.Context.hasSameType(T1, T2)) {
S.Diag(Templated->getLocation(),
diag::note_ovl_candidate_inconsistent_deduction_types)
<< ParamD->getDeclName() << *DeductionFailure.getFirstArg() << T1
<< *DeductionFailure.getSecondArg() << T2;
MaybeEmitInheritedConstructorNote(S, Found);
return;
}
which = 1;
} else {
which = 2;
}
// Tweak the diagnostic if the problem is that we deduced packs of
// different arities. We'll print the actual packs anyway in case that
// includes additional useful information.
if (DeductionFailure.getFirstArg()->getKind() == TemplateArgument::Pack &&
DeductionFailure.getSecondArg()->getKind() == TemplateArgument::Pack &&
DeductionFailure.getFirstArg()->pack_size() !=
DeductionFailure.getSecondArg()->pack_size()) {
which = 3;
}
S.Diag(Templated->getLocation(),
diag::note_ovl_candidate_inconsistent_deduction)
<< which << ParamD->getDeclName() << *DeductionFailure.getFirstArg()
<< *DeductionFailure.getSecondArg();
MaybeEmitInheritedConstructorNote(S, Found);
return;
}
case Sema::TDK_InvalidExplicitArguments:
assert(ParamD && "no parameter found for invalid explicit arguments");
if (ParamD->getDeclName())
S.Diag(Templated->getLocation(),
diag::note_ovl_candidate_explicit_arg_mismatch_named)
<< ParamD->getDeclName();
else {
int index = 0;
if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(ParamD))
index = TTP->getIndex();
else if (NonTypeTemplateParmDecl *NTTP
= dyn_cast<NonTypeTemplateParmDecl>(ParamD))
index = NTTP->getIndex();
else
index = cast<TemplateTemplateParmDecl>(ParamD)->getIndex();
S.Diag(Templated->getLocation(),
diag::note_ovl_candidate_explicit_arg_mismatch_unnamed)
<< (index + 1);
}
MaybeEmitInheritedConstructorNote(S, Found);
return;
case Sema::TDK_ConstraintsNotSatisfied: {
// Format the template argument list into the argument string.
SmallString<128> TemplateArgString;
TemplateArgumentList *Args = DeductionFailure.getTemplateArgumentList();
TemplateArgString = " ";
TemplateArgString += S.getTemplateArgumentBindingsText(
getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
if (TemplateArgString.size() == 1)
TemplateArgString.clear();
S.Diag(Templated->getLocation(),
diag::note_ovl_candidate_unsatisfied_constraints)
<< TemplateArgString;
S.DiagnoseUnsatisfiedConstraint(
static_cast<CNSInfo*>(DeductionFailure.Data)->Satisfaction);
return;
}
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
DiagnoseArityMismatch(S, Found, Templated, NumArgs);
return;
case Sema::TDK_InstantiationDepth:
S.Diag(Templated->getLocation(),
diag::note_ovl_candidate_instantiation_depth);
MaybeEmitInheritedConstructorNote(S, Found);
return;
case Sema::TDK_SubstitutionFailure: {
// Format the template argument list into the argument string.
SmallString<128> TemplateArgString;
if (TemplateArgumentList *Args =
DeductionFailure.getTemplateArgumentList()) {
TemplateArgString = " ";
TemplateArgString += S.getTemplateArgumentBindingsText(
getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
if (TemplateArgString.size() == 1)
TemplateArgString.clear();
}
// If this candidate was disabled by enable_if, say so.
PartialDiagnosticAt *PDiag = DeductionFailure.getSFINAEDiagnostic();
if (PDiag && PDiag->second.getDiagID() ==
diag::err_typename_nested_not_found_enable_if) {
// FIXME: Use the source range of the condition, and the fully-qualified
// name of the enable_if template. These are both present in PDiag.
S.Diag(PDiag->first, diag::note_ovl_candidate_disabled_by_enable_if)
<< "'enable_if'" << TemplateArgString;
return;
}
// We found a specific requirement that disabled the enable_if.
if (PDiag && PDiag->second.getDiagID() ==
diag::err_typename_nested_not_found_requirement) {
S.Diag(Templated->getLocation(),
diag::note_ovl_candidate_disabled_by_requirement)
<< PDiag->second.getStringArg(0) << TemplateArgString;
return;
}
// Format the SFINAE diagnostic into the argument string.
// FIXME: Add a general mechanism to include a PartialDiagnostic *'s
// formatted message in another diagnostic.
SmallString<128> SFINAEArgString;
SourceRange R;
if (PDiag) {
SFINAEArgString = ": ";
R = SourceRange(PDiag->first, PDiag->first);
PDiag->second.EmitToString(S.getDiagnostics(), SFINAEArgString);
}
S.Diag(Templated->getLocation(),
diag::note_ovl_candidate_substitution_failure)
<< TemplateArgString << SFINAEArgString << R;
MaybeEmitInheritedConstructorNote(S, Found);
return;
}
case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested: {
// Format the template argument list into the argument string.
SmallString<128> TemplateArgString;
if (TemplateArgumentList *Args =
DeductionFailure.getTemplateArgumentList()) {
TemplateArgString = " ";
TemplateArgString += S.getTemplateArgumentBindingsText(
getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
if (TemplateArgString.size() == 1)
TemplateArgString.clear();
}
S.Diag(Templated->getLocation(), diag::note_ovl_candidate_deduced_mismatch)
<< (*DeductionFailure.getCallArgIndex() + 1)
<< *DeductionFailure.getFirstArg() << *DeductionFailure.getSecondArg()
<< TemplateArgString
<< (DeductionFailure.Result == Sema::TDK_DeducedMismatchNested);
break;
}
case Sema::TDK_NonDeducedMismatch: {
// FIXME: Provide a source location to indicate what we couldn't match.
TemplateArgument FirstTA = *DeductionFailure.getFirstArg();
TemplateArgument SecondTA = *DeductionFailure.getSecondArg();
if (FirstTA.getKind() == TemplateArgument::Template &&
SecondTA.getKind() == TemplateArgument::Template) {
TemplateName FirstTN = FirstTA.getAsTemplate();
TemplateName SecondTN = SecondTA.getAsTemplate();
if (FirstTN.getKind() == TemplateName::Template &&
SecondTN.getKind() == TemplateName::Template) {
if (FirstTN.getAsTemplateDecl()->getName() ==
SecondTN.getAsTemplateDecl()->getName()) {
// FIXME: This fixes a bad diagnostic where both templates are named
// the same. This particular case is a bit difficult since:
// 1) It is passed as a string to the diagnostic printer.
// 2) The diagnostic printer only attempts to find a better
// name for types, not decls.
// Ideally, this should folded into the diagnostic printer.
S.Diag(Templated->getLocation(),
diag::note_ovl_candidate_non_deduced_mismatch_qualified)
<< FirstTN.getAsTemplateDecl() << SecondTN.getAsTemplateDecl();
return;
}
}
}
if (TakingCandidateAddress && isa<FunctionDecl>(Templated) &&
!checkAddressOfCandidateIsAvailable(S, cast<FunctionDecl>(Templated)))
return;
// FIXME: For generic lambda parameters, check if the function is a lambda
// call operator, and if so, emit a prettier and more informative
// diagnostic that mentions 'auto' and lambda in addition to
// (or instead of?) the canonical template type parameters.
S.Diag(Templated->getLocation(),
diag::note_ovl_candidate_non_deduced_mismatch)
<< FirstTA << SecondTA;
return;
}
// TODO: diagnose these individually, then kill off
// note_ovl_candidate_bad_deduction, which is uselessly vague.
case Sema::TDK_MiscellaneousDeductionFailure:
S.Diag(Templated->getLocation(), diag::note_ovl_candidate_bad_deduction);
MaybeEmitInheritedConstructorNote(S, Found);
return;
case Sema::TDK_CUDATargetMismatch:
S.Diag(Templated->getLocation(),
diag::note_cuda_ovl_candidate_target_mismatch);
return;
}
}
/// Diagnose a failed template-argument deduction, for function calls.
static void DiagnoseBadDeduction(Sema &S, OverloadCandidate *Cand,
unsigned NumArgs,
bool TakingCandidateAddress) {
unsigned TDK = Cand->DeductionFailure.Result;
if (TDK == Sema::TDK_TooFewArguments || TDK == Sema::TDK_TooManyArguments) {
if (CheckArityMismatch(S, Cand, NumArgs))
return;
}
DiagnoseBadDeduction(S, Cand->FoundDecl, Cand->Function, // pattern
Cand->DeductionFailure, NumArgs, TakingCandidateAddress);
}
/// CUDA: diagnose an invalid call across targets.
static void DiagnoseBadTarget(Sema &S, OverloadCandidate *Cand) {
FunctionDecl *Caller = cast<FunctionDecl>(S.CurContext);
FunctionDecl *Callee = Cand->Function;
Sema::CUDAFunctionTarget CallerTarget = S.IdentifyCUDATarget(Caller),
CalleeTarget = S.IdentifyCUDATarget(Callee);
std::string FnDesc;
std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
ClassifyOverloadCandidate(S, Cand->FoundDecl, Callee,
Cand->getRewriteKind(), FnDesc);
S.Diag(Callee->getLocation(), diag::note_ovl_candidate_bad_target)
<< (unsigned)FnKindPair.first << (unsigned)ocs_non_template
<< FnDesc /* Ignored */
<< CalleeTarget << CallerTarget;
// This could be an implicit constructor for which we could not infer the
// target due to a collsion. Diagnose that case.
CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Callee);
if (Meth != nullptr && Meth->isImplicit()) {
CXXRecordDecl *ParentClass = Meth->getParent();
Sema::CXXSpecialMember CSM;
switch (FnKindPair.first) {
default:
return;
case oc_implicit_default_constructor:
CSM = Sema::CXXDefaultConstructor;
break;
case oc_implicit_copy_constructor:
CSM = Sema::CXXCopyConstructor;
break;
case oc_implicit_move_constructor:
CSM = Sema::CXXMoveConstructor;
break;
case oc_implicit_copy_assignment:
CSM = Sema::CXXCopyAssignment;
break;
case oc_implicit_move_assignment:
CSM = Sema::CXXMoveAssignment;
break;
};
bool ConstRHS = false;
if (Meth->getNumParams()) {
if (const ReferenceType *RT =
Meth->getParamDecl(0)->getType()->getAs<ReferenceType>()) {
ConstRHS = RT->getPointeeType().isConstQualified();
}
}
S.inferCUDATargetForImplicitSpecialMember(ParentClass, CSM, Meth,
/* ConstRHS */ ConstRHS,
/* Diagnose */ true);
}
}
static void DiagnoseFailedEnableIfAttr(Sema &S, OverloadCandidate *Cand) {
FunctionDecl *Callee = Cand->Function;
EnableIfAttr *Attr = static_cast<EnableIfAttr*>(Cand->DeductionFailure.Data);
S.Diag(Callee->getLocation(),
diag::note_ovl_candidate_disabled_by_function_cond_attr)
<< Attr->getCond()->getSourceRange() << Attr->getMessage();
}
static void DiagnoseFailedExplicitSpec(Sema &S, OverloadCandidate *Cand) {
ExplicitSpecifier ES = ExplicitSpecifier::getFromDecl(Cand->Function);
assert(ES.isExplicit() && "not an explicit candidate");
unsigned Kind;
switch (Cand->Function->getDeclKind()) {
case Decl::Kind::CXXConstructor:
Kind = 0;
break;
case Decl::Kind::CXXConversion:
Kind = 1;
break;
case Decl::Kind::CXXDeductionGuide:
Kind = Cand->Function->isImplicit() ? 0 : 2;
break;
default:
llvm_unreachable("invalid Decl");
}
// Note the location of the first (in-class) declaration; a redeclaration
// (particularly an out-of-class definition) will typically lack the
// 'explicit' specifier.
// FIXME: This is probably a good thing to do for all 'candidate' notes.
FunctionDecl *First = Cand->Function->getFirstDecl();
if (FunctionDecl *Pattern = First->getTemplateInstantiationPattern())
First = Pattern->getFirstDecl();
S.Diag(First->getLocation(),
diag::note_ovl_candidate_explicit)
<< Kind << (ES.getExpr() ? 1 : 0)
<< (ES.getExpr() ? ES.getExpr()->getSourceRange() : SourceRange());
}
/// Generates a 'note' diagnostic for an overload candidate. We've
/// already generated a primary error at the call site.
///
/// It really does need to be a single diagnostic with its caret
/// pointed at the candidate declaration. Yes, this creates some
/// major challenges of technical writing. Yes, this makes pointing
/// out problems with specific arguments quite awkward. It's still
/// better than generating twenty screens of text for every failed
/// overload.
///
/// It would be great to be able to express per-candidate problems
/// more richly for those diagnostic clients that cared, but we'd
/// still have to be just as careful with the default diagnostics.
/// \param CtorDestAS Addr space of object being constructed (for ctor
/// candidates only).
static void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand,
unsigned NumArgs,
bool TakingCandidateAddress,
LangAS CtorDestAS = LangAS::Default) {
FunctionDecl *Fn = Cand->Function;
if (shouldSkipNotingLambdaConversionDecl(Fn))
return;
// Note deleted candidates, but only if they're viable.
if (Cand->Viable) {
if (Fn->isDeleted()) {
std::string FnDesc;
std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn,
Cand->getRewriteKind(), FnDesc);
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_deleted)
<< (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
<< (Fn->isDeleted() ? (Fn->isDeletedAsWritten() ? 1 : 2) : 0);
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
// We don't really have anything else to say about viable candidates.
S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind());
return;
}
switch (Cand->FailureKind) {
case ovl_fail_too_many_arguments:
case ovl_fail_too_few_arguments:
return DiagnoseArityMismatch(S, Cand, NumArgs);
case ovl_fail_bad_deduction:
return DiagnoseBadDeduction(S, Cand, NumArgs,
TakingCandidateAddress);
case ovl_fail_illegal_constructor: {
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_illegal_constructor)
<< (Fn->getPrimaryTemplate() ? 1 : 0);
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
case ovl_fail_object_addrspace_mismatch: {
Qualifiers QualsForPrinting;
QualsForPrinting.setAddressSpace(CtorDestAS);
S.Diag(Fn->getLocation(),
diag::note_ovl_candidate_illegal_constructor_adrspace_mismatch)
<< QualsForPrinting;
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
}
case ovl_fail_trivial_conversion:
case ovl_fail_bad_final_conversion:
case ovl_fail_final_conversion_not_exact:
return S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind());
case ovl_fail_bad_conversion: {
unsigned I = (Cand->IgnoreObjectArgument ? 1 : 0);
for (unsigned N = Cand->Conversions.size(); I != N; ++I)
if (Cand->Conversions[I].isBad())
return DiagnoseBadConversion(S, Cand, I, TakingCandidateAddress);
// FIXME: this currently happens when we're called from SemaInit
// when user-conversion overload fails. Figure out how to handle
// those conditions and diagnose them well.
return S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind());
}
case ovl_fail_bad_target:
return DiagnoseBadTarget(S, Cand);
case ovl_fail_enable_if:
return DiagnoseFailedEnableIfAttr(S, Cand);
case ovl_fail_explicit:
return DiagnoseFailedExplicitSpec(S, Cand);
case ovl_fail_inhctor_slice:
// It's generally not interesting to note copy/move constructors here.
if (cast<CXXConstructorDecl>(Fn)->isCopyOrMoveConstructor())
return;
S.Diag(Fn->getLocation(),
diag::note_ovl_candidate_inherited_constructor_slice)
<< (Fn->getPrimaryTemplate() ? 1 : 0)
<< Fn->getParamDecl(0)->getType()->isRValueReferenceType();
MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
return;
case ovl_fail_addr_not_available: {
bool Available = checkAddressOfCandidateIsAvailable(S, Cand->Function);
(void)Available;
assert(!Available);
break;
}
case ovl_non_default_multiversion_function:
// Do nothing, these should simply be ignored.
break;
case ovl_fail_constraints_not_satisfied: {
std::string FnDesc;
std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn,
Cand->getRewriteKind(), FnDesc);
S.Diag(Fn->getLocation(),
diag::note_ovl_candidate_constraints_not_satisfied)
<< (unsigned)FnKindPair.first << (unsigned)ocs_non_template
<< FnDesc /* Ignored */;
ConstraintSatisfaction Satisfaction;
if (S.CheckFunctionConstraints(Fn, Satisfaction))
break;
S.DiagnoseUnsatisfiedConstraint(Satisfaction);
}
}
}
static void NoteSurrogateCandidate(Sema &S, OverloadCandidate *Cand) {
if (shouldSkipNotingLambdaConversionDecl(Cand->Surrogate))
return;
// Desugar the type of the surrogate down to a function type,
// retaining as many typedefs as possible while still showing
// the function type (and, therefore, its parameter types).
QualType FnType = Cand->Surrogate->getConversionType();
bool isLValueReference = false;
bool isRValueReference = false;
bool isPointer = false;
if (const LValueReferenceType *FnTypeRef =
FnType->getAs<LValueReferenceType>()) {
FnType = FnTypeRef->getPointeeType();
isLValueReference = true;
} else if (const RValueReferenceType *FnTypeRef =
FnType->getAs<RValueReferenceType>()) {
FnType = FnTypeRef->getPointeeType();
isRValueReference = true;
}
if (const PointerType *FnTypePtr = FnType->getAs<PointerType>()) {
FnType = FnTypePtr->getPointeeType();
isPointer = true;
}
// Desugar down to a function type.
FnType = QualType(FnType->getAs<FunctionType>(), 0);
// Reconstruct the pointer/reference as appropriate.
if (isPointer) FnType = S.Context.getPointerType(FnType);
if (isRValueReference) FnType = S.Context.getRValueReferenceType(FnType);
if (isLValueReference) FnType = S.Context.getLValueReferenceType(FnType);
S.Diag(Cand->Surrogate->getLocation(), diag::note_ovl_surrogate_cand)
<< FnType;
}
static void NoteBuiltinOperatorCandidate(Sema &S, StringRef Opc,
SourceLocation OpLoc,
OverloadCandidate *Cand) {
assert(Cand->Conversions.size() <= 2 && "builtin operator is not binary");
std::string TypeStr("operator");
TypeStr += Opc;
TypeStr += "(";
TypeStr += Cand->BuiltinParamTypes[0].getAsString();
if (Cand->Conversions.size() == 1) {
TypeStr += ")";
S.Diag(OpLoc, diag::note_ovl_builtin_candidate) << TypeStr;
} else {
TypeStr += ", ";
TypeStr += Cand->BuiltinParamTypes[1].getAsString();
TypeStr += ")";
S.Diag(OpLoc, diag::note_ovl_builtin_candidate) << TypeStr;
}
}
static void NoteAmbiguousUserConversions(Sema &S, SourceLocation OpLoc,
OverloadCandidate *Cand) {
for (const ImplicitConversionSequence &ICS : Cand->Conversions) {
if (ICS.isBad()) break; // all meaningless after first invalid
if (!ICS.isAmbiguous()) continue;
ICS.DiagnoseAmbiguousConversion(
S, OpLoc, S.PDiag(diag::note_ambiguous_type_conversion));
}
}
static SourceLocation GetLocationForCandidate(const OverloadCandidate *Cand) {
if (Cand->Function)
return Cand->Function->getLocation();
if (Cand->IsSurrogate)
return Cand->Surrogate->getLocation();
return SourceLocation();
}
static unsigned RankDeductionFailure(const DeductionFailureInfo &DFI) {
switch ((Sema::TemplateDeductionResult)DFI.Result) {
case Sema::TDK_Success:
case Sema::TDK_NonDependentConversionFailure:
llvm_unreachable("non-deduction failure while diagnosing bad deduction");
case Sema::TDK_Invalid:
case Sema::TDK_Incomplete:
case Sema::TDK_IncompletePack:
return 1;
case Sema::TDK_Underqualified:
case Sema::TDK_Inconsistent:
return 2;
case Sema::TDK_SubstitutionFailure:
case Sema::TDK_DeducedMismatch:
case Sema::TDK_ConstraintsNotSatisfied:
case Sema::TDK_DeducedMismatchNested:
case Sema::TDK_NonDeducedMismatch:
case Sema::TDK_MiscellaneousDeductionFailure:
case Sema::TDK_CUDATargetMismatch:
return 3;
case Sema::TDK_InstantiationDepth:
return 4;
case Sema::TDK_InvalidExplicitArguments:
return 5;
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
return 6;
}
llvm_unreachable("Unhandled deduction result");
}
namespace {
struct CompareOverloadCandidatesForDisplay {
Sema &S;
SourceLocation Loc;
size_t NumArgs;
OverloadCandidateSet::CandidateSetKind CSK;
CompareOverloadCandidatesForDisplay(
Sema &S, SourceLocation Loc, size_t NArgs,
OverloadCandidateSet::CandidateSetKind CSK)
: S(S), NumArgs(NArgs), CSK(CSK) {}
OverloadFailureKind EffectiveFailureKind(const OverloadCandidate *C) const {
// If there are too many or too few arguments, that's the high-order bit we
// want to sort by, even if the immediate failure kind was something else.
if (C->FailureKind == ovl_fail_too_many_arguments ||
C->FailureKind == ovl_fail_too_few_arguments)
return static_cast<OverloadFailureKind>(C->FailureKind);
if (C->Function) {
if (NumArgs > C->Function->getNumParams() && !C->Function->isVariadic())
return ovl_fail_too_many_arguments;
if (NumArgs < C->Function->getMinRequiredArguments())
return ovl_fail_too_few_arguments;
}
return static_cast<OverloadFailureKind>(C->FailureKind);
}
bool operator()(const OverloadCandidate *L,
const OverloadCandidate *R) {
// Fast-path this check.
if (L == R) return false;
// Order first by viability.
if (L->Viable) {
if (!R->Viable) return true;
// TODO: introduce a tri-valued comparison for overload
// candidates. Would be more worthwhile if we had a sort
// that could exploit it.
if (isBetterOverloadCandidate(S, *L, *R, SourceLocation(), CSK))
return true;
if (isBetterOverloadCandidate(S, *R, *L, SourceLocation(), CSK))
return false;
} else if (R->Viable)
return false;
assert(L->Viable == R->Viable);
// Criteria by which we can sort non-viable candidates:
if (!L->Viable) {
OverloadFailureKind LFailureKind = EffectiveFailureKind(L);
OverloadFailureKind RFailureKind = EffectiveFailureKind(R);
// 1. Arity mismatches come after other candidates.
if (LFailureKind == ovl_fail_too_many_arguments ||
LFailureKind == ovl_fail_too_few_arguments) {
if (RFailureKind == ovl_fail_too_many_arguments ||
RFailureKind == ovl_fail_too_few_arguments) {
int LDist = std::abs((int)L->getNumParams() - (int)NumArgs);
int RDist = std::abs((int)R->getNumParams() - (int)NumArgs);
if (LDist == RDist) {
if (LFailureKind == RFailureKind)
// Sort non-surrogates before surrogates.
return !L->IsSurrogate && R->IsSurrogate;
// Sort candidates requiring fewer parameters than there were
// arguments given after candidates requiring more parameters
// than there were arguments given.
return LFailureKind == ovl_fail_too_many_arguments;
}
return LDist < RDist;
}
return false;
}
if (RFailureKind == ovl_fail_too_many_arguments ||
RFailureKind == ovl_fail_too_few_arguments)
return true;
// 2. Bad conversions come first and are ordered by the number
// of bad conversions and quality of good conversions.
if (LFailureKind == ovl_fail_bad_conversion) {
if (RFailureKind != ovl_fail_bad_conversion)
return true;
// The conversion that can be fixed with a smaller number of changes,
// comes first.
unsigned numLFixes = L->Fix.NumConversionsFixed;
unsigned numRFixes = R->Fix.NumConversionsFixed;
numLFixes = (numLFixes == 0) ? UINT_MAX : numLFixes;
numRFixes = (numRFixes == 0) ? UINT_MAX : numRFixes;
if (numLFixes != numRFixes) {
return numLFixes < numRFixes;
}
// If there's any ordering between the defined conversions...
// FIXME: this might not be transitive.
assert(L->Conversions.size() == R->Conversions.size());
int leftBetter = 0;
unsigned I = (L->IgnoreObjectArgument || R->IgnoreObjectArgument);
for (unsigned E = L->Conversions.size(); I != E; ++I) {
switch (CompareImplicitConversionSequences(S, Loc,
L->Conversions[I],
R->Conversions[I])) {
case ImplicitConversionSequence::Better:
leftBetter++;
break;
case ImplicitConversionSequence::Worse:
leftBetter--;
break;
case ImplicitConversionSequence::Indistinguishable:
break;
}
}
if (leftBetter > 0) return true;
if (leftBetter < 0) return false;
} else if (RFailureKind == ovl_fail_bad_conversion)
return false;
if (LFailureKind == ovl_fail_bad_deduction) {
if (RFailureKind != ovl_fail_bad_deduction)
return true;
if (L->DeductionFailure.Result != R->DeductionFailure.Result)
return RankDeductionFailure(L->DeductionFailure)
< RankDeductionFailure(R->DeductionFailure);
} else if (RFailureKind == ovl_fail_bad_deduction)
return false;
// TODO: others?
}
// Sort everything else by location.
SourceLocation LLoc = GetLocationForCandidate(L);
SourceLocation RLoc = GetLocationForCandidate(R);
// Put candidates without locations (e.g. builtins) at the end.
if (LLoc.isInvalid()) return false;
if (RLoc.isInvalid()) return true;
return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc);
}
};
}
/// CompleteNonViableCandidate - Normally, overload resolution only
/// computes up to the first bad conversion. Produces the FixIt set if
/// possible.
static void
CompleteNonViableCandidate(Sema &S, OverloadCandidate *Cand,
ArrayRef<Expr *> Args,
OverloadCandidateSet::CandidateSetKind CSK) {
assert(!Cand->Viable);
// Don't do anything on failures other than bad conversion.
if (Cand->FailureKind != ovl_fail_bad_conversion)
return;
// We only want the FixIts if all the arguments can be corrected.
bool Unfixable = false;
// Use a implicit copy initialization to check conversion fixes.
Cand->Fix.setConversionChecker(TryCopyInitialization);
// Attempt to fix the bad conversion.
unsigned ConvCount = Cand->Conversions.size();
for (unsigned ConvIdx = (Cand->IgnoreObjectArgument ? 1 : 0); /**/;
++ConvIdx) {
assert(ConvIdx != ConvCount && "no bad conversion in candidate");
if (Cand->Conversions[ConvIdx].isInitialized() &&
Cand->Conversions[ConvIdx].isBad()) {
Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S);
break;
}
}
// FIXME: this should probably be preserved from the overload
// operation somehow.
bool SuppressUserConversions = false;
unsigned ConvIdx = 0;
unsigned ArgIdx = 0;
ArrayRef<QualType> ParamTypes;
bool Reversed = Cand->isReversed();
if (Cand->IsSurrogate) {
QualType ConvType
= Cand->Surrogate->getConversionType().getNonReferenceType();
if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>())
ConvType = ConvPtrType->getPointeeType();
ParamTypes = ConvType->castAs<FunctionProtoType>()->getParamTypes();
// Conversion 0 is 'this', which doesn't have a corresponding parameter.
ConvIdx = 1;
} else if (Cand->Function) {
ParamTypes =
Cand->Function->getType()->castAs<FunctionProtoType>()->getParamTypes();
if (isa<CXXMethodDecl>(Cand->Function) &&
!isa<CXXConstructorDecl>(Cand->Function) && !Reversed) {
// Conversion 0 is 'this', which doesn't have a corresponding parameter.
ConvIdx = 1;
if (CSK == OverloadCandidateSet::CSK_Operator &&
Cand->Function->getDeclName().getCXXOverloadedOperator() != OO_Call)
// Argument 0 is 'this', which doesn't have a corresponding parameter.
ArgIdx = 1;
}
} else {
// Builtin operator.
assert(ConvCount <= 3);
ParamTypes = Cand->BuiltinParamTypes;
}
// Fill in the rest of the conversions.
for (unsigned ParamIdx = Reversed ? ParamTypes.size() - 1 : 0;
ConvIdx != ConvCount;
++ConvIdx, ++ArgIdx, ParamIdx += (Reversed ? -1 : 1)) {
assert(ArgIdx < Args.size() && "no argument for this arg conversion");
if (Cand->Conversions[ConvIdx].isInitialized()) {
// We've already checked this conversion.
} else if (ParamIdx < ParamTypes.size()) {
if (ParamTypes[ParamIdx]->isDependentType())
Cand->Conversions[ConvIdx].setAsIdentityConversion(
Args[ArgIdx]->getType());
else {
Cand->Conversions[ConvIdx] =
TryCopyInitialization(S, Args[ArgIdx], ParamTypes[ParamIdx],
SuppressUserConversions,
/*InOverloadResolution=*/true,
/*AllowObjCWritebackConversion=*/
S.getLangOpts().ObjCAutoRefCount);
// Store the FixIt in the candidate if it exists.
if (!Unfixable && Cand->Conversions[ConvIdx].isBad())
Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S);
}
} else
Cand->Conversions[ConvIdx].setEllipsis();
}
}
SmallVector<OverloadCandidate *, 32> OverloadCandidateSet::CompleteCandidates(
Sema &S, OverloadCandidateDisplayKind OCD, ArrayRef<Expr *> Args,
SourceLocation OpLoc,
llvm::function_ref<bool(OverloadCandidate &)> Filter) {
// Sort the candidates by viability and position. Sorting directly would
// be prohibitive, so we make a set of pointers and sort those.
SmallVector<OverloadCandidate*, 32> Cands;
if (OCD == OCD_AllCandidates) Cands.reserve(size());
for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) {
if (!Filter(*Cand))
continue;
switch (OCD) {
case OCD_AllCandidates:
if (!Cand->Viable) {
if (!Cand->Function && !Cand->IsSurrogate) {
// This a non-viable builtin candidate. We do not, in general,
// want to list every possible builtin candidate.
continue;
}
CompleteNonViableCandidate(S, Cand, Args, Kind);
}
break;
case OCD_ViableCandidates:
if (!Cand->Viable)
continue;
break;
case OCD_AmbiguousCandidates:
if (!Cand->Best)
continue;
break;
}
Cands.push_back(Cand);
}
llvm::stable_sort(
Cands, CompareOverloadCandidatesForDisplay(S, OpLoc, Args.size(), Kind));
return Cands;
}
bool OverloadCandidateSet::shouldDeferDiags(Sema &S, ArrayRef<Expr *> Args,
SourceLocation OpLoc) {
bool DeferHint = false;
if (S.getLangOpts().CUDA && S.getLangOpts().GPUDeferDiag) {
// Defer diagnostic for CUDA/HIP if there are wrong-sided candidates or
// host device candidates.
auto WrongSidedCands =
CompleteCandidates(S, OCD_AllCandidates, Args, OpLoc, [](auto &Cand) {
return (Cand.Viable == false &&
Cand.FailureKind == ovl_fail_bad_target) ||
(Cand.Function &&
Cand.Function->template hasAttr<CUDAHostAttr>() &&
Cand.Function->template hasAttr<CUDADeviceAttr>());
});
DeferHint = !WrongSidedCands.empty();
}
return DeferHint;
}
/// When overload resolution fails, prints diagnostic messages containing the
/// candidates in the candidate set.
void OverloadCandidateSet::NoteCandidates(
PartialDiagnosticAt PD, Sema &S, OverloadCandidateDisplayKind OCD,
ArrayRef<Expr *> Args, StringRef Opc, SourceLocation OpLoc,
llvm::function_ref<bool(OverloadCandidate &)> Filter) {
auto Cands = CompleteCandidates(S, OCD, Args, OpLoc, Filter);
S.Diag(PD.first, PD.second, shouldDeferDiags(S, Args, OpLoc));
NoteCandidates(S, Args, Cands, Opc, OpLoc);
if (OCD == OCD_AmbiguousCandidates)
MaybeDiagnoseAmbiguousConstraints(S, {begin(), end()});
}
void OverloadCandidateSet::NoteCandidates(Sema &S, ArrayRef<Expr *> Args,
ArrayRef<OverloadCandidate *> Cands,
StringRef Opc, SourceLocation OpLoc) {
bool ReportedAmbiguousConversions = false;
const OverloadsShown ShowOverloads = S.Diags.getShowOverloads();
unsigned CandsShown = 0;
auto I = Cands.begin(), E = Cands.end();
for (; I != E; ++I) {
OverloadCandidate *Cand = *I;
if (CandsShown >= S.Diags.getNumOverloadCandidatesToShow() &&
ShowOverloads == Ovl_Best) {
break;
}
++CandsShown;
if (Cand->Function)
NoteFunctionCandidate(S, Cand, Args.size(),
/*TakingCandidateAddress=*/false, DestAS);
else if (Cand->IsSurrogate)
NoteSurrogateCandidate(S, Cand);
else {
assert(Cand->Viable &&
"Non-viable built-in candidates are not added to Cands.");
// Generally we only see ambiguities including viable builtin
// operators if overload resolution got screwed up by an
// ambiguous user-defined conversion.
//
// FIXME: It's quite possible for different conversions to see
// different ambiguities, though.
if (!ReportedAmbiguousConversions) {
NoteAmbiguousUserConversions(S, OpLoc, Cand);
ReportedAmbiguousConversions = true;
}
// If this is a viable builtin, print it.
NoteBuiltinOperatorCandidate(S, Opc, OpLoc, Cand);
}
}
// Inform S.Diags that we've shown an overload set with N elements. This may
// inform the future value of S.Diags.getNumOverloadCandidatesToShow().
S.Diags.overloadCandidatesShown(CandsShown);
if (I != E)
S.Diag(OpLoc, diag::note_ovl_too_many_candidates,
shouldDeferDiags(S, Args, OpLoc))
<< int(E - I);
}
static SourceLocation
GetLocationForCandidate(const TemplateSpecCandidate *Cand) {
return Cand->Specialization ? Cand->Specialization->getLocation()
: SourceLocation();
}
namespace {
struct CompareTemplateSpecCandidatesForDisplay {
Sema &S;
CompareTemplateSpecCandidatesForDisplay(Sema &S) : S(S) {}
bool operator()(const TemplateSpecCandidate *L,
const TemplateSpecCandidate *R) {
// Fast-path this check.
if (L == R)
return false;
// Assuming that both candidates are not matches...
// Sort by the ranking of deduction failures.
if (L->DeductionFailure.Result != R->DeductionFailure.Result)
return RankDeductionFailure(L->DeductionFailure) <
RankDeductionFailure(R->DeductionFailure);
// Sort everything else by location.
SourceLocation LLoc = GetLocationForCandidate(L);
SourceLocation RLoc = GetLocationForCandidate(R);
// Put candidates without locations (e.g. builtins) at the end.
if (LLoc.isInvalid())
return false;
if (RLoc.isInvalid())
return true;
return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc);
}
};
}
/// Diagnose a template argument deduction failure.
/// We are treating these failures as overload failures due to bad
/// deductions.
void TemplateSpecCandidate::NoteDeductionFailure(Sema &S,
bool ForTakingAddress) {
DiagnoseBadDeduction(S, FoundDecl, Specialization, // pattern
DeductionFailure, /*NumArgs=*/0, ForTakingAddress);
}
void TemplateSpecCandidateSet::destroyCandidates() {
for (iterator i = begin(), e = end(); i != e; ++i) {
i->DeductionFailure.Destroy();
}
}
void TemplateSpecCandidateSet::clear() {
destroyCandidates();
Candidates.clear();
}
/// NoteCandidates - When no template specialization match is found, prints
/// diagnostic messages containing the non-matching specializations that form
/// the candidate set.
/// This is analoguous to OverloadCandidateSet::NoteCandidates() with
/// OCD == OCD_AllCandidates and Cand->Viable == false.
void TemplateSpecCandidateSet::NoteCandidates(Sema &S, SourceLocation Loc) {
// Sort the candidates by position (assuming no candidate is a match).
// Sorting directly would be prohibitive, so we make a set of pointers
// and sort those.
SmallVector<TemplateSpecCandidate *, 32> Cands;
Cands.reserve(size());
for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) {
if (Cand->Specialization)
Cands.push_back(Cand);
// Otherwise, this is a non-matching builtin candidate. We do not,
// in general, want to list every possible builtin candidate.
}
llvm::sort(Cands, CompareTemplateSpecCandidatesForDisplay(S));
// FIXME: Perhaps rename OverloadsShown and getShowOverloads()
// for generalization purposes (?).
const OverloadsShown ShowOverloads = S.Diags.getShowOverloads();
SmallVectorImpl<TemplateSpecCandidate *>::iterator I, E;
unsigned CandsShown = 0;
for (I = Cands.begin(), E = Cands.end(); I != E; ++I) {
TemplateSpecCandidate *Cand = *I;
// Set an arbitrary limit on the number of candidates we'll spam
// the user with. FIXME: This limit should depend on details of the
// candidate list.
if (CandsShown >= 4 && ShowOverloads == Ovl_Best)
break;
++CandsShown;
assert(Cand->Specialization &&
"Non-matching built-in candidates are not added to Cands.");
Cand->NoteDeductionFailure(S, ForTakingAddress);
}
if (I != E)
S.Diag(Loc, diag::note_ovl_too_many_candidates) << int(E - I);
}
// [PossiblyAFunctionType] --> [Return]
// NonFunctionType --> NonFunctionType
// R (A) --> R(A)
// R (*)(A) --> R (A)
// R (&)(A) --> R (A)
// R (S::*)(A) --> R (A)
QualType Sema::ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType) {
QualType Ret = PossiblyAFunctionType;
if (const PointerType *ToTypePtr =
PossiblyAFunctionType->getAs<PointerType>())
Ret = ToTypePtr->getPointeeType();
else if (const ReferenceType *ToTypeRef =
PossiblyAFunctionType->getAs<ReferenceType>())
Ret = ToTypeRef->getPointeeType();
else if (const MemberPointerType *MemTypePtr =
PossiblyAFunctionType->getAs<MemberPointerType>())
Ret = MemTypePtr->getPointeeType();
Ret =
Context.getCanonicalType(Ret).getUnqualifiedType();
return Ret;
}
static bool completeFunctionType(Sema &S, FunctionDecl *FD, SourceLocation Loc,
bool Complain = true) {
if (S.getLangOpts().CPlusPlus14 && FD->getReturnType()->isUndeducedType() &&
S.DeduceReturnType(FD, Loc, Complain))
return true;
auto *FPT = FD->getType()->castAs<FunctionProtoType>();
if (S.getLangOpts().CPlusPlus17 &&
isUnresolvedExceptionSpec(FPT->getExceptionSpecType()) &&
!S.ResolveExceptionSpec(Loc, FPT))
return true;
return false;
}
namespace {
// A helper class to help with address of function resolution
// - allows us to avoid passing around all those ugly parameters
class AddressOfFunctionResolver {
Sema& S;
Expr* SourceExpr;
const QualType& TargetType;
QualType TargetFunctionType; // Extracted function type from target type
bool Complain;
//DeclAccessPair& ResultFunctionAccessPair;
ASTContext& Context;
bool TargetTypeIsNonStaticMemberFunction;
bool FoundNonTemplateFunction;
bool StaticMemberFunctionFromBoundPointer;
bool HasComplained;
OverloadExpr::FindResult OvlExprInfo;
OverloadExpr *OvlExpr;
TemplateArgumentListInfo OvlExplicitTemplateArgs;
SmallVector<std::pair<DeclAccessPair, FunctionDecl*>, 4> Matches;
TemplateSpecCandidateSet FailedCandidates;
public:
AddressOfFunctionResolver(Sema &S, Expr *SourceExpr,
const QualType &TargetType, bool Complain)
: S(S), SourceExpr(SourceExpr), TargetType(TargetType),
Complain(Complain), Context(S.getASTContext()),
TargetTypeIsNonStaticMemberFunction(
!!TargetType->getAs<MemberPointerType>()),
FoundNonTemplateFunction(false),
StaticMemberFunctionFromBoundPointer(false),
HasComplained(false),
OvlExprInfo(OverloadExpr::find(SourceExpr)),
OvlExpr(OvlExprInfo.Expression),
FailedCandidates(OvlExpr->getNameLoc(), /*ForTakingAddress=*/true) {
ExtractUnqualifiedFunctionTypeFromTargetType();
if (TargetFunctionType->isFunctionType()) {
if (UnresolvedMemberExpr *UME = dyn_cast<UnresolvedMemberExpr>(OvlExpr))
if (!UME->isImplicitAccess() &&
!S.ResolveSingleFunctionTemplateSpecialization(UME))
StaticMemberFunctionFromBoundPointer = true;
} else if (OvlExpr->hasExplicitTemplateArgs()) {
DeclAccessPair dap;
if (FunctionDecl *Fn = S.ResolveSingleFunctionTemplateSpecialization(
OvlExpr, false, &dap)) {
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn))
if (!Method->isStatic()) {
// If the target type is a non-function type and the function found
// is a non-static member function, pretend as if that was the
// target, it's the only possible type to end up with.
TargetTypeIsNonStaticMemberFunction = true;
// And skip adding the function if its not in the proper form.
// We'll diagnose this due to an empty set of functions.
if (!OvlExprInfo.HasFormOfMemberPointer)
return;
}
Matches.push_back(std::make_pair(dap, Fn));
}
return;
}
if (OvlExpr->hasExplicitTemplateArgs())
OvlExpr->copyTemplateArgumentsInto(OvlExplicitTemplateArgs);
if (FindAllFunctionsThatMatchTargetTypeExactly()) {
// C++ [over.over]p4:
// If more than one function is selected, [...]
if (Matches.size() > 1 && !eliminiateSuboptimalOverloadCandidates()) {
if (FoundNonTemplateFunction)
EliminateAllTemplateMatches();
else
EliminateAllExceptMostSpecializedTemplate();
}
}
if (S.getLangOpts().CUDA && Matches.size() > 1)
EliminateSuboptimalCudaMatches();
}
bool hasComplained() const { return HasComplained; }
private:
bool candidateHasExactlyCorrectType(const FunctionDecl *FD) {
QualType Discard;
return Context.hasSameUnqualifiedType(TargetFunctionType, FD->getType()) ||
S.IsFunctionConversion(FD->getType(), TargetFunctionType, Discard);
}
/// \return true if A is considered a better overload candidate for the
/// desired type than B.
bool isBetterCandidate(const FunctionDecl *A, const FunctionDecl *B) {
// If A doesn't have exactly the correct type, we don't want to classify it
// as "better" than anything else. This way, the user is required to
// disambiguate for us if there are multiple candidates and no exact match.
return candidateHasExactlyCorrectType(A) &&
(!candidateHasExactlyCorrectType(B) ||
compareEnableIfAttrs(S, A, B) == Comparison::Better);
}
/// \return true if we were able to eliminate all but one overload candidate,
/// false otherwise.
bool eliminiateSuboptimalOverloadCandidates() {
// Same algorithm as overload resolution -- one pass to pick the "best",
// another pass to be sure that nothing is better than the best.
auto Best = Matches.begin();
for (auto I = Matches.begin()+1, E = Matches.end(); I != E; ++I)
if (isBetterCandidate(I->second, Best->second))
Best = I;
const FunctionDecl *BestFn = Best->second;
auto IsBestOrInferiorToBest = [this, BestFn](
const std::pair<DeclAccessPair, FunctionDecl *> &Pair) {
return BestFn == Pair.second || isBetterCandidate(BestFn, Pair.second);
};
// Note: We explicitly leave Matches unmodified if there isn't a clear best
// option, so we can potentially give the user a better error
if (!llvm::all_of(Matches, IsBestOrInferiorToBest))
return false;
Matches[0] = *Best;
Matches.resize(1);
return true;
}
bool isTargetTypeAFunction() const {
return TargetFunctionType->isFunctionType();
}
// [ToType] [Return]
// R (*)(A) --> R (A), IsNonStaticMemberFunction = false
// R (&)(A) --> R (A), IsNonStaticMemberFunction = false
// R (S::*)(A) --> R (A), IsNonStaticMemberFunction = true
void inline ExtractUnqualifiedFunctionTypeFromTargetType() {
TargetFunctionType = S.ExtractUnqualifiedFunctionType(TargetType);
}
// return true if any matching specializations were found
bool AddMatchingTemplateFunction(FunctionTemplateDecl* FunctionTemplate,
const DeclAccessPair& CurAccessFunPair) {
if (CXXMethodDecl *Method
= dyn_cast<CXXMethodDecl>(FunctionTemplate->getTemplatedDecl())) {
// Skip non-static function templates when converting to pointer, and
// static when converting to member pointer.
if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction)
return false;
}
else if (TargetTypeIsNonStaticMemberFunction)
return false;
// C++ [over.over]p2:
// If the name is a function template, template argument deduction is
// done (14.8.2.2), and if the argument deduction succeeds, the
// resulting template argument list is used to generate a single
// function template specialization, which is added to the set of
// overloaded functions considered.
FunctionDecl *Specialization = nullptr;
TemplateDeductionInfo Info(FailedCandidates.getLocation());
if (Sema::TemplateDeductionResult Result
= S.DeduceTemplateArguments(FunctionTemplate,
&OvlExplicitTemplateArgs,
TargetFunctionType, Specialization,
Info, /*IsAddressOfFunction*/true)) {
// Make a note of the failed deduction for diagnostics.
FailedCandidates.addCandidate()
.set(CurAccessFunPair, FunctionTemplate->getTemplatedDecl(),
MakeDeductionFailureInfo(Context, Result, Info));
return false;
}
// Template argument deduction ensures that we have an exact match or
// compatible pointer-to-function arguments that would be adjusted by ICS.
// This function template specicalization works.
assert(S.isSameOrCompatibleFunctionType(
Context.getCanonicalType(Specialization->getType()),
Context.getCanonicalType(TargetFunctionType)));
if (!S.checkAddressOfFunctionIsAvailable(Specialization))
return false;
Matches.push_back(std::make_pair(CurAccessFunPair, Specialization));
return true;
}
bool AddMatchingNonTemplateFunction(NamedDecl* Fn,
const DeclAccessPair& CurAccessFunPair) {
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) {
// Skip non-static functions when converting to pointer, and static
// when converting to member pointer.
if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction)
return false;
}
else if (TargetTypeIsNonStaticMemberFunction)
return false;
if (FunctionDecl *FunDecl = dyn_cast<FunctionDecl>(Fn)) {
if (S.getLangOpts().CUDA)
if (FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext))
if (!Caller->isImplicit() && !S.IsAllowedCUDACall(Caller, FunDecl))
return false;
if (FunDecl->isMultiVersion()) {
const auto *TA = FunDecl->getAttr<TargetAttr>();
if (TA && !TA->isDefaultVersion())
return false;
}
// If any candidate has a placeholder return type, trigger its deduction
// now.
if (completeFunctionType(S, FunDecl, SourceExpr->getBeginLoc(),
Complain)) {
HasComplained |= Complain;
return false;
}
if (!S.checkAddressOfFunctionIsAvailable(FunDecl))
return false;
// If we're in C, we need to support types that aren't exactly identical.
if (!S.getLangOpts().CPlusPlus ||
candidateHasExactlyCorrectType(FunDecl)) {
Matches.push_back(std::make_pair(
CurAccessFunPair, cast<FunctionDecl>(FunDecl->getCanonicalDecl())));
FoundNonTemplateFunction = true;
return true;
}
}
return false;
}
bool FindAllFunctionsThatMatchTargetTypeExactly() {
bool Ret = false;
// If the overload expression doesn't have the form of a pointer to
// member, don't try to convert it to a pointer-to-member type.
if (IsInvalidFormOfPointerToMemberFunction())
return false;
for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
E = OvlExpr->decls_end();
I != E; ++I) {
// Look through any using declarations to find the underlying function.
NamedDecl *Fn = (*I)->getUnderlyingDecl();
// C++ [over.over]p3:
// Non-member functions and static member functions match
// targets of type "pointer-to-function" or "reference-to-function."
// Nonstatic member functions match targets of
// type "pointer-to-member-function."
// Note that according to DR 247, the containing class does not matter.
if (FunctionTemplateDecl *FunctionTemplate
= dyn_cast<FunctionTemplateDecl>(Fn)) {
if (AddMatchingTemplateFunction(FunctionTemplate, I.getPair()))
Ret = true;
}
// If we have explicit template arguments supplied, skip non-templates.
else if (!OvlExpr->hasExplicitTemplateArgs() &&
AddMatchingNonTemplateFunction(Fn, I.getPair()))
Ret = true;
}
assert(Ret || Matches.empty());
return Ret;
}
void EliminateAllExceptMostSpecializedTemplate() {
// [...] and any given function template specialization F1 is
// eliminated if the set contains a second function template
// specialization whose function template is more specialized
// than the function template of F1 according to the partial
// ordering rules of 14.5.5.2.
// The algorithm specified above is quadratic. We instead use a
// two-pass algorithm (similar to the one used to identify the
// best viable function in an overload set) that identifies the
// best function template (if it exists).
UnresolvedSet<4> MatchesCopy; // TODO: avoid!
for (unsigned I = 0, E = Matches.size(); I != E; ++I)
MatchesCopy.addDecl(Matches[I].second, Matches[I].first.getAccess());
// TODO: It looks like FailedCandidates does not serve much purpose
// here, since the no_viable diagnostic has index 0.
UnresolvedSetIterator Result = S.getMostSpecialized(
MatchesCopy.begin(), MatchesCopy.end(), FailedCandidates,
SourceExpr->getBeginLoc(), S.PDiag(),
S.PDiag(diag::err_addr_ovl_ambiguous)
<< Matches[0].second->getDeclName(),
S.PDiag(diag::note_ovl_candidate)
<< (unsigned)oc_function << (unsigned)ocs_described_template,
Complain, TargetFunctionType);
if (Result != MatchesCopy.end()) {
// Make it the first and only element
Matches[0].first = Matches[Result - MatchesCopy.begin()].first;
Matches[0].second = cast<FunctionDecl>(*Result);
Matches.resize(1);
} else
HasComplained |= Complain;
}
void EliminateAllTemplateMatches() {
// [...] any function template specializations in the set are
// eliminated if the set also contains a non-template function, [...]
for (unsigned I = 0, N = Matches.size(); I != N; ) {
if (Matches[I].second->getPrimaryTemplate() == nullptr)
++I;
else {
Matches[I] = Matches[--N];
Matches.resize(N);
}
}
}
void EliminateSuboptimalCudaMatches() {
S.EraseUnwantedCUDAMatches(dyn_cast<FunctionDecl>(S.CurContext), Matches);
}
public:
void ComplainNoMatchesFound() const {
assert(Matches.empty());
S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_no_viable)
<< OvlExpr->getName() << TargetFunctionType
<< OvlExpr->getSourceRange();
if (FailedCandidates.empty())
S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType,
/*TakingAddress=*/true);
else {
// We have some deduction failure messages. Use them to diagnose
// the function templates, and diagnose the non-template candidates
// normally.
for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
IEnd = OvlExpr->decls_end();
I != IEnd; ++I)
if (FunctionDecl *Fun =
dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl()))
if (!functionHasPassObjectSizeParams(Fun))
S.NoteOverloadCandidate(*I, Fun, CRK_None, TargetFunctionType,
/*TakingAddress=*/true);
FailedCandidates.NoteCandidates(S, OvlExpr->getBeginLoc());
}
}
bool IsInvalidFormOfPointerToMemberFunction() const {
return TargetTypeIsNonStaticMemberFunction &&
!OvlExprInfo.HasFormOfMemberPointer;
}
void ComplainIsInvalidFormOfPointerToMemberFunction() const {
// TODO: Should we condition this on whether any functions might
// have matched, or is it more appropriate to do that in callers?
// TODO: a fixit wouldn't hurt.
S.Diag(OvlExpr->getNameLoc(), diag::err_addr_ovl_no_qualifier)
<< TargetType << OvlExpr->getSourceRange();
}
bool IsStaticMemberFunctionFromBoundPointer() const {
return StaticMemberFunctionFromBoundPointer;
}
void ComplainIsStaticMemberFunctionFromBoundPointer() const {
S.Diag(OvlExpr->getBeginLoc(),
diag::err_invalid_form_pointer_member_function)
<< OvlExpr->getSourceRange();
}
void ComplainOfInvalidConversion() const {
S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_not_func_ptrref)
<< OvlExpr->getName() << TargetType;
}
void ComplainMultipleMatchesFound() const {
assert(Matches.size() > 1);
S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_ambiguous)
<< OvlExpr->getName() << OvlExpr->getSourceRange();
S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType,
/*TakingAddress=*/true);
}
bool hadMultipleCandidates() const { return (OvlExpr->getNumDecls() > 1); }
int getNumMatches() const { return Matches.size(); }
FunctionDecl* getMatchingFunctionDecl() const {
if (Matches.size() != 1) return nullptr;
return Matches[0].second;
}
const DeclAccessPair* getMatchingFunctionAccessPair() const {
if (Matches.size() != 1) return nullptr;
return &Matches[0].first;
}
};
}
/// ResolveAddressOfOverloadedFunction - Try to resolve the address of
/// an overloaded function (C++ [over.over]), where @p From is an
/// expression with overloaded function type and @p ToType is the type
/// we're trying to resolve to. For example:
///
/// @code
/// int f(double);
/// int f(int);
///
/// int (*pfd)(double) = f; // selects f(double)
/// @endcode
///
/// This routine returns the resulting FunctionDecl if it could be
/// resolved, and NULL otherwise. When @p Complain is true, this
/// routine will emit diagnostics if there is an error.
FunctionDecl *
Sema::ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr,
QualType TargetType,
bool Complain,
DeclAccessPair &FoundResult,
bool *pHadMultipleCandidates) {
assert(AddressOfExpr->getType() == Context.OverloadTy);
AddressOfFunctionResolver Resolver(*this, AddressOfExpr, TargetType,
Complain);
int NumMatches = Resolver.getNumMatches();
FunctionDecl *Fn = nullptr;
bool ShouldComplain = Complain && !Resolver.hasComplained();
if (NumMatches == 0 && ShouldComplain) {
if (Resolver.IsInvalidFormOfPointerToMemberFunction())
Resolver.ComplainIsInvalidFormOfPointerToMemberFunction();
else
Resolver.ComplainNoMatchesFound();
}
else if (NumMatches > 1 && ShouldComplain)
Resolver.ComplainMultipleMatchesFound();
else if (NumMatches == 1) {
Fn = Resolver.getMatchingFunctionDecl();
assert(Fn);
if (auto *FPT = Fn->getType()->getAs<FunctionProtoType>())
ResolveExceptionSpec(AddressOfExpr->getExprLoc(), FPT);
FoundResult = *Resolver.getMatchingFunctionAccessPair();
if (Complain) {
if (Resolver.IsStaticMemberFunctionFromBoundPointer())
Resolver.ComplainIsStaticMemberFunctionFromBoundPointer();
else
CheckAddressOfMemberAccess(AddressOfExpr, FoundResult);
}
}
if (pHadMultipleCandidates)
*pHadMultipleCandidates = Resolver.hadMultipleCandidates();
return Fn;
}
/// Given an expression that refers to an overloaded function, try to
/// resolve that function to a single function that can have its address taken.
/// This will modify `Pair` iff it returns non-null.
///
/// This routine can only succeed if from all of the candidates in the overload
/// set for SrcExpr that can have their addresses taken, there is one candidate
/// that is more constrained than the rest.
FunctionDecl *
Sema::resolveAddressOfSingleOverloadCandidate(Expr *E, DeclAccessPair &Pair) {
OverloadExpr::FindResult R = OverloadExpr::find(E);
OverloadExpr *Ovl = R.Expression;
bool IsResultAmbiguous = false;
FunctionDecl *Result = nullptr;
DeclAccessPair DAP;
SmallVector<FunctionDecl *, 2> AmbiguousDecls;
auto CheckMoreConstrained =
[&] (FunctionDecl *FD1, FunctionDecl *FD2) -> Optional<bool> {
SmallVector<const Expr *, 1> AC1, AC2;
FD1->getAssociatedConstraints(AC1);
FD2->getAssociatedConstraints(AC2);
bool AtLeastAsConstrained1, AtLeastAsConstrained2;
if (IsAtLeastAsConstrained(FD1, AC1, FD2, AC2, AtLeastAsConstrained1))
return None;
if (IsAtLeastAsConstrained(FD2, AC2, FD1, AC1, AtLeastAsConstrained2))
return None;
if (AtLeastAsConstrained1 == AtLeastAsConstrained2)
return None;
return AtLeastAsConstrained1;
};
// Don't use the AddressOfResolver because we're specifically looking for
// cases where we have one overload candidate that lacks
// enable_if/pass_object_size/...
for (auto I = Ovl->decls_begin(), E = Ovl->decls_end(); I != E; ++I) {
auto *FD = dyn_cast<FunctionDecl>(I->getUnderlyingDecl());
if (!FD)
return nullptr;
if (!checkAddressOfFunctionIsAvailable(FD))
continue;
// We have more than one result - see if it is more constrained than the
// previous one.
if (Result) {
Optional<bool> MoreConstrainedThanPrevious = CheckMoreConstrained(FD,
Result);
if (!MoreConstrainedThanPrevious) {
IsResultAmbiguous = true;
AmbiguousDecls.push_back(FD);
continue;
}
if (!*MoreConstrainedThanPrevious)
continue;
// FD is more constrained - replace Result with it.
}
IsResultAmbiguous = false;
DAP = I.getPair();
Result = FD;
}
if (IsResultAmbiguous)
return nullptr;
if (Result) {
SmallVector<const Expr *, 1> ResultAC;
// We skipped over some ambiguous declarations which might be ambiguous with
// the selected result.
for (FunctionDecl *Skipped : AmbiguousDecls)
if (!CheckMoreConstrained(Skipped, Result).hasValue())
return nullptr;
Pair = DAP;
}
return Result;
}
/// Given an overloaded function, tries to turn it into a non-overloaded
/// function reference using resolveAddressOfSingleOverloadCandidate. This
/// will perform access checks, diagnose the use of the resultant decl, and, if
/// requested, potentially perform a function-to-pointer decay.
///
/// Returns false if resolveAddressOfSingleOverloadCandidate fails.
/// Otherwise, returns true. This may emit diagnostics and return true.
bool Sema::resolveAndFixAddressOfSingleOverloadCandidate(
ExprResult &SrcExpr, bool DoFunctionPointerConverion) {
Expr *E = SrcExpr.get();
assert(E->getType() == Context.OverloadTy && "SrcExpr must be an overload");
DeclAccessPair DAP;
FunctionDecl *Found = resolveAddressOfSingleOverloadCandidate(E, DAP);
if (!Found || Found->isCPUDispatchMultiVersion() ||
Found->isCPUSpecificMultiVersion())
return false;
// Emitting multiple diagnostics for a function that is both inaccessible and
// unavailable is consistent with our behavior elsewhere. So, always check
// for both.
DiagnoseUseOfDecl(Found, E->getExprLoc());
CheckAddressOfMemberAccess(E, DAP);
Expr *Fixed = FixOverloadedFunctionReference(E, DAP, Found);
if (DoFunctionPointerConverion && Fixed->getType()->isFunctionType())
SrcExpr = DefaultFunctionArrayConversion(Fixed, /*Diagnose=*/false);
else
SrcExpr = Fixed;
return true;
}
/// Given an expression that refers to an overloaded function, try to
/// resolve that overloaded function expression down to a single function.
///
/// This routine can only resolve template-ids that refer to a single function
/// template, where that template-id refers to a single template whose template
/// arguments are either provided by the template-id or have defaults,
/// as described in C++0x [temp.arg.explicit]p3.
///
/// If no template-ids are found, no diagnostics are emitted and NULL is
/// returned.
FunctionDecl *
Sema::ResolveSingleFunctionTemplateSpecialization(OverloadExpr *ovl,
bool Complain,
DeclAccessPair *FoundResult) {
// C++ [over.over]p1:
// [...] [Note: any redundant set of parentheses surrounding the
// overloaded function name is ignored (5.1). ]
// C++ [over.over]p1:
// [...] The overloaded function name can be preceded by the &
// operator.
// If we didn't actually find any template-ids, we're done.
if (!ovl->hasExplicitTemplateArgs())
return nullptr;
TemplateArgumentListInfo ExplicitTemplateArgs;
ovl->copyTemplateArgumentsInto(ExplicitTemplateArgs);
TemplateSpecCandidateSet FailedCandidates(ovl->getNameLoc());
// Look through all of the overloaded functions, searching for one
// whose type matches exactly.
FunctionDecl *Matched = nullptr;
for (UnresolvedSetIterator I = ovl->decls_begin(),
E = ovl->decls_end(); I != E; ++I) {
// C++0x [temp.arg.explicit]p3:
// [...] In contexts where deduction is done and fails, or in contexts
// where deduction is not done, if a template argument list is
// specified and it, along with any default template arguments,
// identifies a single function template specialization, then the
// template-id is an lvalue for the function template specialization.
FunctionTemplateDecl *FunctionTemplate
= cast<FunctionTemplateDecl>((*I)->getUnderlyingDecl());
// C++ [over.over]p2:
// If the name is a function template, template argument deduction is
// done (14.8.2.2), and if the argument deduction succeeds, the
// resulting template argument list is used to generate a single
// function template specialization, which is added to the set of
// overloaded functions considered.
FunctionDecl *Specialization = nullptr;
TemplateDeductionInfo Info(FailedCandidates.getLocation());
if (TemplateDeductionResult Result
= DeduceTemplateArguments(FunctionTemplate, &ExplicitTemplateArgs,
Specialization, Info,
/*IsAddressOfFunction*/true)) {
// Make a note of the failed deduction for diagnostics.
// TODO: Actually use the failed-deduction info?
FailedCandidates.addCandidate()
.set(I.getPair(), FunctionTemplate->getTemplatedDecl(),
MakeDeductionFailureInfo(Context, Result, Info));
continue;
}
assert(Specialization && "no specialization and no error?");
// Multiple matches; we can't resolve to a single declaration.
if (Matched) {
if (Complain) {
Diag(ovl->getExprLoc(), diag::err_addr_ovl_ambiguous)
<< ovl->getName();
NoteAllOverloadCandidates(ovl);
}
return nullptr;
}
Matched = Specialization;
if (FoundResult) *FoundResult = I.getPair();
}
if (Matched &&
completeFunctionType(*this, Matched, ovl->getExprLoc(), Complain))
return nullptr;
return Matched;
}
// Resolve and fix an overloaded expression that can be resolved
// because it identifies a single function template specialization.
//
// Last three arguments should only be supplied if Complain = true
//
// Return true if it was logically possible to so resolve the
// expression, regardless of whether or not it succeeded. Always
// returns true if 'complain' is set.
bool Sema::ResolveAndFixSingleFunctionTemplateSpecialization(
ExprResult &SrcExpr, bool doFunctionPointerConverion,
bool complain, SourceRange OpRangeForComplaining,
QualType DestTypeForComplaining,
unsigned DiagIDForComplaining) {
assert(SrcExpr.get()->getType() == Context.OverloadTy);
OverloadExpr::FindResult ovl = OverloadExpr::find(SrcExpr.get());
DeclAccessPair found;
ExprResult SingleFunctionExpression;
if (FunctionDecl *fn = ResolveSingleFunctionTemplateSpecialization(
ovl.Expression, /*complain*/ false, &found)) {
if (DiagnoseUseOfDecl(fn, SrcExpr.get()->getBeginLoc())) {
SrcExpr = ExprError();
return true;
}
// It is only correct to resolve to an instance method if we're
// resolving a form that's permitted to be a pointer to member.
// Otherwise we'll end up making a bound member expression, which
// is illegal in all the contexts we resolve like this.
if (!ovl.HasFormOfMemberPointer &&
isa<CXXMethodDecl>(fn) &&
cast<CXXMethodDecl>(fn)->isInstance()) {
if (!complain) return false;
Diag(ovl.Expression->getExprLoc(),
diag::err_bound_member_function)
<< 0 << ovl.Expression->getSourceRange();
// TODO: I believe we only end up here if there's a mix of
// static and non-static candidates (otherwise the expression
// would have 'bound member' type, not 'overload' type).
// Ideally we would note which candidate was chosen and why
// the static candidates were rejected.
SrcExpr = ExprError();
return true;
}
// Fix the expression to refer to 'fn'.
SingleFunctionExpression =
FixOverloadedFunctionReference(SrcExpr.get(), found, fn);
// If desired, do function-to-pointer decay.
if (doFunctionPointerConverion) {
SingleFunctionExpression =
DefaultFunctionArrayLvalueConversion(SingleFunctionExpression.get());
if (SingleFunctionExpression.isInvalid()) {
SrcExpr = ExprError();
return true;
}
}
}
if (!SingleFunctionExpression.isUsable()) {
if (complain) {
Diag(OpRangeForComplaining.getBegin(), DiagIDForComplaining)
<< ovl.Expression->getName()
<< DestTypeForComplaining
<< OpRangeForComplaining
<< ovl.Expression->getQualifierLoc().getSourceRange();
NoteAllOverloadCandidates(SrcExpr.get());
SrcExpr = ExprError();
return true;
}
return false;
}
SrcExpr = SingleFunctionExpression;
return true;
}
/// Add a single candidate to the overload set.
static void AddOverloadedCallCandidate(Sema &S,
DeclAccessPair FoundDecl,
TemplateArgumentListInfo *ExplicitTemplateArgs,
ArrayRef<Expr *> Args,
OverloadCandidateSet &CandidateSet,
bool PartialOverloading,
bool KnownValid) {
NamedDecl *Callee = FoundDecl.getDecl();
if (isa<UsingShadowDecl>(Callee))
Callee = cast<UsingShadowDecl>(Callee)->getTargetDecl();
if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Callee)) {
if (ExplicitTemplateArgs) {
assert(!KnownValid && "Explicit template arguments?");
return;
}
// Prevent ill-formed function decls to be added as overload candidates.
if (!dyn_cast<FunctionProtoType>(Func->getType()->getAs<FunctionType>()))
return;
S.AddOverloadCandidate(Func, FoundDecl, Args, CandidateSet,
/*SuppressUserConversions=*/false,
PartialOverloading);
return;
}
if (FunctionTemplateDecl *FuncTemplate
= dyn_cast<FunctionTemplateDecl>(Callee)) {
S.AddTemplateOverloadCandidate(FuncTemplate, FoundDecl,
ExplicitTemplateArgs, Args, CandidateSet,
/*SuppressUserConversions=*/false,
PartialOverloading);
return;
}
assert(!KnownValid && "unhandled case in overloaded call candidate");
}
/// Add the overload candidates named by callee and/or found by argument
/// dependent lookup to the given overload set.
void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE,
ArrayRef<Expr *> Args,
OverloadCandidateSet &CandidateSet,
bool PartialOverloading) {
#ifndef NDEBUG
// Verify that ArgumentDependentLookup is consistent with the rules
// in C++0x [basic.lookup.argdep]p3:
//
// Let X be the lookup set produced by unqualified lookup (3.4.1)
// and let Y be the lookup set produced by argument dependent
// lookup (defined as follows). If X contains
//
// -- a declaration of a class member, or
//
// -- a block-scope function declaration that is not a
// using-declaration, or
//
// -- a declaration that is neither a function or a function
// template
//
// then Y is empty.
if (ULE->requiresADL()) {
for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(),
E = ULE->decls_end(); I != E; ++I) {
assert(!(*I)->getDeclContext()->isRecord());
assert(isa<UsingShadowDecl>(*I) ||
!(*I)->getDeclContext()->isFunctionOrMethod());
assert((*I)->getUnderlyingDecl()->isFunctionOrFunctionTemplate());
}
}
#endif
// It would be nice to avoid this copy.
TemplateArgumentListInfo TABuffer;
TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr;
if (ULE->hasExplicitTemplateArgs()) {
ULE->copyTemplateArgumentsInto(TABuffer);
ExplicitTemplateArgs = &TABuffer;
}
for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(),
E = ULE->decls_end(); I != E; ++I)
AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, Args,
CandidateSet, PartialOverloading,
/*KnownValid*/ true);
if (ULE->requiresADL())
AddArgumentDependentLookupCandidates(ULE->getName(), ULE->getExprLoc(),
Args, ExplicitTemplateArgs,
CandidateSet, PartialOverloading);
}
/// Add the call candidates from the given set of lookup results to the given
/// overload set. Non-function lookup results are ignored.
void Sema::AddOverloadedCallCandidates(
LookupResult &R, TemplateArgumentListInfo *ExplicitTemplateArgs,
ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet) {
for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I)
AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, Args,
CandidateSet, false, /*KnownValid*/ false);
}
/// Determine whether a declaration with the specified name could be moved into
/// a different namespace.
static bool canBeDeclaredInNamespace(const DeclarationName &Name) {
switch (Name.getCXXOverloadedOperator()) {
case OO_New: case OO_Array_New:
case OO_Delete: case OO_Array_Delete:
return false;
default:
return true;
}
}
/// Attempt to recover from an ill-formed use of a non-dependent name in a
/// template, where the non-dependent name was declared after the template
/// was defined. This is common in code written for a compilers which do not
/// correctly implement two-stage name lookup.
///
/// Returns true if a viable candidate was found and a diagnostic was issued.
static bool DiagnoseTwoPhaseLookup(
Sema &SemaRef, SourceLocation FnLoc, const CXXScopeSpec &SS,
LookupResult &R, OverloadCandidateSet::CandidateSetKind CSK,
TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
CXXRecordDecl **FoundInClass = nullptr) {
if (!SemaRef.inTemplateInstantiation() || !SS.isEmpty())
return false;
for (DeclContext *DC = SemaRef.CurContext; DC; DC = DC->getParent()) {
if (DC->isTransparentContext())
continue;
SemaRef.LookupQualifiedName(R, DC);
if (!R.empty()) {
R.suppressDiagnostics();
OverloadCandidateSet Candidates(FnLoc, CSK);
SemaRef.AddOverloadedCallCandidates(R, ExplicitTemplateArgs, Args,
Candidates);
OverloadCandidateSet::iterator Best;
OverloadingResult OR =
Candidates.BestViableFunction(SemaRef, FnLoc, Best);
if (auto *RD = dyn_cast<CXXRecordDecl>(DC)) {
// We either found non-function declarations or a best viable function
// at class scope. A class-scope lookup result disables ADL. Don't
// look past this, but let the caller know that we found something that
// either is, or might be, usable in this class.
if (FoundInClass) {
*FoundInClass = RD;
if (OR == OR_Success) {
R.clear();
R.addDecl(Best->FoundDecl.getDecl(), Best->FoundDecl.getAccess());
R.resolveKind();
}
}
return false;
}
if (OR != OR_Success) {
// There wasn't a unique best function or function template.
return false;
}
// Find the namespaces where ADL would have looked, and suggest
// declaring the function there instead.
Sema::AssociatedNamespaceSet AssociatedNamespaces;
Sema::AssociatedClassSet AssociatedClasses;
SemaRef.FindAssociatedClassesAndNamespaces(FnLoc, Args,
AssociatedNamespaces,
AssociatedClasses);
Sema::AssociatedNamespaceSet SuggestedNamespaces;
if (canBeDeclaredInNamespace(R.getLookupName())) {
DeclContext *Std = SemaRef.getStdNamespace();
for (Sema::AssociatedNamespaceSet::iterator
it = AssociatedNamespaces.begin(),
end = AssociatedNamespaces.end(); it != end; ++it) {
// Never suggest declaring a function within namespace 'std'.
if (Std && Std->Encloses(*it))
continue;
// Never suggest declaring a function within a namespace with a
// reserved name, like __gnu_cxx.
NamespaceDecl *NS = dyn_cast<NamespaceDecl>(*it);
if (NS &&
NS->getQualifiedNameAsString().find("__") != std::string::npos)
continue;
SuggestedNamespaces.insert(*it);
}
}
SemaRef.Diag(R.getNameLoc(), diag::err_not_found_by_two_phase_lookup)
<< R.getLookupName();
if (SuggestedNamespaces.empty()) {
SemaRef.Diag(Best->Function->getLocation(),
diag::note_not_found_by_two_phase_lookup)
<< R.getLookupName() << 0;
} else if (SuggestedNamespaces.size() == 1) {
SemaRef.Diag(Best->Function->getLocation(),
diag::note_not_found_by_two_phase_lookup)
<< R.getLookupName() << 1 << *SuggestedNamespaces.begin();
} else {
// FIXME: It would be useful to list the associated namespaces here,
// but the diagnostics infrastructure doesn't provide a way to produce
// a localized representation of a list of items.
SemaRef.Diag(Best->Function->getLocation(),
diag::note_not_found_by_two_phase_lookup)
<< R.getLookupName() << 2;
}
// Try to recover by calling this function.
return true;
}
R.clear();
}
return false;
}
/// Attempt to recover from ill-formed use of a non-dependent operator in a
/// template, where the non-dependent operator was declared after the template
/// was defined.
///
/// Returns true if a viable candidate was found and a diagnostic was issued.
static bool
DiagnoseTwoPhaseOperatorLookup(Sema &SemaRef, OverloadedOperatorKind Op,
SourceLocation OpLoc,
ArrayRef<Expr *> Args) {
DeclarationName OpName =
SemaRef.Context.DeclarationNames.getCXXOperatorName(Op);
LookupResult R(SemaRef, OpName, OpLoc, Sema::LookupOperatorName);
return DiagnoseTwoPhaseLookup(SemaRef, OpLoc, CXXScopeSpec(), R,
OverloadCandidateSet::CSK_Operator,
/*ExplicitTemplateArgs=*/nullptr, Args);
}
namespace {
class BuildRecoveryCallExprRAII {
Sema &SemaRef;
public:
BuildRecoveryCallExprRAII(Sema &S) : SemaRef(S) {
assert(SemaRef.IsBuildingRecoveryCallExpr == false);
SemaRef.IsBuildingRecoveryCallExpr = true;
}
~BuildRecoveryCallExprRAII() {
SemaRef.IsBuildingRecoveryCallExpr = false;
}
};
}
/// Attempts to recover from a call where no functions were found.
///
/// This function will do one of three things:
/// * Diagnose, recover, and return a recovery expression.
/// * Diagnose, fail to recover, and return ExprError().
/// * Do not diagnose, do not recover, and return ExprResult(). The caller is
/// expected to diagnose as appropriate.
static ExprResult
BuildRecoveryCallExpr(Sema &SemaRef, Scope *S, Expr *Fn,
UnresolvedLookupExpr *ULE,
SourceLocation LParenLoc,
MutableArrayRef<Expr *> Args,
SourceLocation RParenLoc,
bool EmptyLookup, bool AllowTypoCorrection) {
// Do not try to recover if it is already building a recovery call.
// This stops infinite loops for template instantiations like
//
// template <typename T> auto foo(T t) -> decltype(foo(t)) {}
// template <typename T> auto foo(T t) -> decltype(foo(&t)) {}
if (SemaRef.IsBuildingRecoveryCallExpr)
return ExprResult();
BuildRecoveryCallExprRAII RCE(SemaRef);
CXXScopeSpec SS;
SS.Adopt(ULE->getQualifierLoc());
SourceLocation TemplateKWLoc = ULE->getTemplateKeywordLoc();
TemplateArgumentListInfo TABuffer;
TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr;
if (ULE->hasExplicitTemplateArgs()) {
ULE->copyTemplateArgumentsInto(TABuffer);
ExplicitTemplateArgs = &TABuffer;
}
LookupResult R(SemaRef, ULE->getName(), ULE->getNameLoc(),
Sema::LookupOrdinaryName);
CXXRecordDecl *FoundInClass = nullptr;
if (DiagnoseTwoPhaseLookup(SemaRef, Fn->getExprLoc(), SS, R,
OverloadCandidateSet::CSK_Normal,
ExplicitTemplateArgs, Args, &FoundInClass)) {
// OK, diagnosed a two-phase lookup issue.
} else if (EmptyLookup) {
// Try to recover from an empty lookup with typo correction.
R.clear();
NoTypoCorrectionCCC NoTypoValidator{};
FunctionCallFilterCCC FunctionCallValidator(SemaRef, Args.size(),
ExplicitTemplateArgs != nullptr,
dyn_cast<MemberExpr>(Fn));
CorrectionCandidateCallback &Validator =
AllowTypoCorrection
? static_cast<CorrectionCandidateCallback &>(FunctionCallValidator)
: static_cast<CorrectionCandidateCallback &>(NoTypoValidator);
if (SemaRef.DiagnoseEmptyLookup(S, SS, R, Validator, ExplicitTemplateArgs,
Args))
return ExprError();
} else if (FoundInClass && SemaRef.getLangOpts().MSVCCompat) {
// We found a usable declaration of the name in a dependent base of some
// enclosing class.
// FIXME: We should also explain why the candidates found by name lookup
// were not viable.
if (SemaRef.DiagnoseDependentMemberLookup(R))
return ExprError();
} else {
// We had viable candidates and couldn't recover; let the caller diagnose
// this.
return ExprResult();
}
// If we get here, we should have issued a diagnostic and formed a recovery
// lookup result.
assert(!R.empty() && "lookup results empty despite recovery");
// If recovery created an ambiguity, just bail out.
if (R.isAmbiguous()) {
R.suppressDiagnostics();
return ExprError();
}
// Build an implicit member call if appropriate. Just drop the
// casts and such from the call, we don't really care.
ExprResult NewFn = ExprError();
if ((*R.begin())->isCXXClassMember())
NewFn = SemaRef.BuildPossibleImplicitMemberExpr(SS, TemplateKWLoc, R,
ExplicitTemplateArgs, S);
else if (ExplicitTemplateArgs || TemplateKWLoc.isValid())
NewFn = SemaRef.BuildTemplateIdExpr(SS, TemplateKWLoc, R, false,
ExplicitTemplateArgs);
else
NewFn = SemaRef.BuildDeclarationNameExpr(SS, R, false);
if (NewFn.isInvalid())
return ExprError();
// This shouldn't cause an infinite loop because we're giving it
// an expression with viable lookup results, which should never
// end up here.
return SemaRef.BuildCallExpr(/*Scope*/ nullptr, NewFn.get(), LParenLoc,
MultiExprArg(Args.data(), Args.size()),
RParenLoc);
}
/// Constructs and populates an OverloadedCandidateSet from
/// the given function.
/// \returns true when an the ExprResult output parameter has been set.
bool Sema::buildOverloadedCallSet(Scope *S, Expr *Fn,
UnresolvedLookupExpr *ULE,
MultiExprArg Args,
SourceLocation RParenLoc,
OverloadCandidateSet *CandidateSet,
ExprResult *Result) {
#ifndef NDEBUG
if (ULE->requiresADL()) {
// To do ADL, we must have found an unqualified name.
assert(!ULE->getQualifier() && "qualified name with ADL");
// We don't perform ADL for implicit declarations of builtins.
// Verify that this was correctly set up.
FunctionDecl *F;
if (ULE->decls_begin() != ULE->decls_end() &&
ULE->decls_begin() + 1 == ULE->decls_end() &&
(F = dyn_cast<FunctionDecl>(*ULE->decls_begin())) &&
F->getBuiltinID() && F->isImplicit())
llvm_unreachable("performing ADL for builtin");
// We don't perform ADL in C.
assert(getLangOpts().CPlusPlus && "ADL enabled in C");
}
#endif
UnbridgedCastsSet UnbridgedCasts;
if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts)) {
*Result = ExprError();
return true;
}
// Add the functions denoted by the callee to the set of candidate
// functions, including those from argument-dependent lookup.
AddOverloadedCallCandidates(ULE, Args, *CandidateSet);
if (getLangOpts().MSVCCompat &&
CurContext->isDependentContext() && !isSFINAEContext() &&
(isa<FunctionDecl>(CurContext) || isa<CXXRecordDecl>(CurContext))) {
OverloadCandidateSet::iterator Best;
if (CandidateSet->empty() ||
CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best) ==
OR_No_Viable_Function) {
// In Microsoft mode, if we are inside a template class member function
// then create a type dependent CallExpr. The goal is to postpone name
// lookup to instantiation time to be able to search into type dependent
// base classes.
CallExpr *CE =
CallExpr::Create(Context, Fn, Args, Context.DependentTy, VK_PRValue,
RParenLoc, CurFPFeatureOverrides());
CE->markDependentForPostponedNameLookup();
*Result = CE;
return true;
}
}
if (CandidateSet->empty())
return false;
UnbridgedCasts.restore();
return false;
}
// Guess at what the return type for an unresolvable overload should be.
static QualType chooseRecoveryType(OverloadCandidateSet &CS,
OverloadCandidateSet::iterator *Best) {
llvm::Optional<QualType> Result;
// Adjust Type after seeing a candidate.
auto ConsiderCandidate = [&](const OverloadCandidate &Candidate) {
if (!Candidate.Function)
return;
if (Candidate.Function->isInvalidDecl())
return;
QualType T = Candidate.Function->getReturnType();
if (T.isNull())
return;
if (!Result)
Result = T;
else if (Result != T)
Result = QualType();
};
// Look for an unambiguous type from a progressively larger subset.
// e.g. if types disagree, but all *viable* overloads return int, choose int.
//
// First, consider only the best candidate.
if (Best && *Best != CS.end())
ConsiderCandidate(**Best);
// Next, consider only viable candidates.
if (!Result)
for (const auto &C : CS)
if (C.Viable)
ConsiderCandidate(C);
// Finally, consider all candidates.
if (!Result)
for (const auto &C : CS)
ConsiderCandidate(C);
if (!Result)
return QualType();
auto Value = Result.getValue();
if (Value.isNull() || Value->isUndeducedType())
return QualType();
return Value;
}
/// FinishOverloadedCallExpr - given an OverloadCandidateSet, builds and returns
/// the completed call expression. If overload resolution fails, emits
/// diagnostics and returns ExprError()
static ExprResult FinishOverloadedCallExpr(Sema &SemaRef, Scope *S, Expr *Fn,
UnresolvedLookupExpr *ULE,
SourceLocation LParenLoc,
MultiExprArg Args,
SourceLocation RParenLoc,
Expr *ExecConfig,
OverloadCandidateSet *CandidateSet,
OverloadCandidateSet::iterator *Best,
OverloadingResult OverloadResult,
bool AllowTypoCorrection) {
switch (OverloadResult) {
case OR_Success: {
FunctionDecl *FDecl = (*Best)->Function;
SemaRef.CheckUnresolvedLookupAccess(ULE, (*Best)->FoundDecl);
if (SemaRef.DiagnoseUseOfDecl(FDecl, ULE->getNameLoc()))
return ExprError();
Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl);
return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc,
ExecConfig, /*IsExecConfig=*/false,
(*Best)->IsADLCandidate);
}
case OR_No_Viable_Function: {
// Try to recover by looking for viable functions which the user might
// have meant to call.
ExprResult Recovery = BuildRecoveryCallExpr(SemaRef, S, Fn, ULE, LParenLoc,
Args, RParenLoc,
CandidateSet->empty(),
AllowTypoCorrection);
if (Recovery.isInvalid() || Recovery.isUsable())
return Recovery;
// If the user passes in a function that we can't take the address of, we
// generally end up emitting really bad error messages. Here, we attempt to
// emit better ones.
for (const Expr *Arg : Args) {
if (!Arg->getType()->isFunctionType())
continue;
if (auto *DRE = dyn_cast<DeclRefExpr>(Arg->IgnoreParenImpCasts())) {
auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl());
if (FD &&
!SemaRef.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
Arg->getExprLoc()))
return ExprError();
}
}
CandidateSet->NoteCandidates(
PartialDiagnosticAt(
Fn->getBeginLoc(),
SemaRef.PDiag(diag::err_ovl_no_viable_function_in_call)
<< ULE->getName() << Fn->getSourceRange()),
SemaRef, OCD_AllCandidates, Args);
break;
}
case OR_Ambiguous:
CandidateSet->NoteCandidates(
PartialDiagnosticAt(Fn->getBeginLoc(),
SemaRef.PDiag(diag::err_ovl_ambiguous_call)
<< ULE->getName() << Fn->getSourceRange()),
SemaRef, OCD_AmbiguousCandidates, Args);
break;
case OR_Deleted: {
CandidateSet->NoteCandidates(
PartialDiagnosticAt(Fn->getBeginLoc(),
SemaRef.PDiag(diag::err_ovl_deleted_call)
<< ULE->getName() << Fn->getSourceRange()),
SemaRef, OCD_AllCandidates, Args);
// We emitted an error for the unavailable/deleted function call but keep
// the call in the AST.
FunctionDecl *FDecl = (*Best)->Function;
Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl);
return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc,
ExecConfig, /*IsExecConfig=*/false,
(*Best)->IsADLCandidate);
}
}
// Overload resolution failed, try to recover.
SmallVector<Expr *, 8> SubExprs = {Fn};
SubExprs.append(Args.begin(), Args.end());
return SemaRef.CreateRecoveryExpr(Fn->getBeginLoc(), RParenLoc, SubExprs,
chooseRecoveryType(*CandidateSet, Best));
}
static void markUnaddressableCandidatesUnviable(Sema &S,
OverloadCandidateSet &CS) {
for (auto I = CS.begin(), E = CS.end(); I != E; ++I) {
if (I->Viable &&
!S.checkAddressOfFunctionIsAvailable(I->Function, /*Complain=*/false)) {
I->Viable = false;
I->FailureKind = ovl_fail_addr_not_available;
}
}
}
/// BuildOverloadedCallExpr - Given the call expression that calls Fn
/// (which eventually refers to the declaration Func) and the call
/// arguments Args/NumArgs, attempt to resolve the function call down
/// to a specific function. If overload resolution succeeds, returns
/// the call expression produced by overload resolution.
/// Otherwise, emits diagnostics and returns ExprError.
ExprResult Sema::BuildOverloadedCallExpr(Scope *S, Expr *Fn,
UnresolvedLookupExpr *ULE,
SourceLocation LParenLoc,
MultiExprArg Args,
SourceLocation RParenLoc,
Expr *ExecConfig,
bool AllowTypoCorrection,
bool CalleesAddressIsTaken) {
OverloadCandidateSet CandidateSet(Fn->getExprLoc(),
OverloadCandidateSet::CSK_Normal);
ExprResult result;
if (buildOverloadedCallSet(S, Fn, ULE, Args, LParenLoc, &CandidateSet,
&result))
return result;
// If the user handed us something like `(&Foo)(Bar)`, we need to ensure that
// functions that aren't addressible are considered unviable.
if (CalleesAddressIsTaken)
markUnaddressableCandidatesUnviable(*this, CandidateSet);
OverloadCandidateSet::iterator Best;
OverloadingResult OverloadResult =
CandidateSet.BestViableFunction(*this, Fn->getBeginLoc(), Best);
return FinishOverloadedCallExpr(*this, S, Fn, ULE, LParenLoc, Args, RParenLoc,
ExecConfig, &CandidateSet, &Best,
OverloadResult, AllowTypoCorrection);
}
static bool IsOverloaded(const UnresolvedSetImpl &Functions) {
return Functions.size() > 1 ||
(Functions.size() == 1 &&
isa<FunctionTemplateDecl>((*Functions.begin())->getUnderlyingDecl()));
}
ExprResult Sema::CreateUnresolvedLookupExpr(CXXRecordDecl *NamingClass,
NestedNameSpecifierLoc NNSLoc,
DeclarationNameInfo DNI,
const UnresolvedSetImpl &Fns,
bool PerformADL) {
return UnresolvedLookupExpr::Create(Context, NamingClass, NNSLoc, DNI,
PerformADL, IsOverloaded(Fns),
Fns.begin(), Fns.end());
}
/// Create a unary operation that may resolve to an overloaded
/// operator.
///
/// \param OpLoc The location of the operator itself (e.g., '*').
///
/// \param Opc The UnaryOperatorKind that describes this operator.
///
/// \param Fns The set of non-member functions that will be
/// considered by overload resolution. The caller needs to build this
/// set based on the context using, e.g.,
/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
/// set should not contain any member functions; those will be added
/// by CreateOverloadedUnaryOp().
///
/// \param Input The input argument.
ExprResult
Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc,
const UnresolvedSetImpl &Fns,
Expr *Input, bool PerformADL) {
OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc);
assert(Op != OO_None && "Invalid opcode for overloaded unary operator");
DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
// TODO: provide better source location info.
DeclarationNameInfo OpNameInfo(OpName, OpLoc);
if (checkPlaceholderForOverload(*this, Input))
return ExprError();
Expr *Args[2] = { Input, nullptr };
unsigned NumArgs = 1;
// For post-increment and post-decrement, add the implicit '0' as
// the second argument, so that we know this is a post-increment or
// post-decrement.
if (Opc == UO_PostInc || Opc == UO_PostDec) {
llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false);
Args[1] = IntegerLiteral::Create(Context, Zero, Context.IntTy,
SourceLocation());
NumArgs = 2;
}
ArrayRef<Expr *> ArgsArray(Args, NumArgs);
if (Input->isTypeDependent()) {
if (Fns.empty())
return UnaryOperator::Create(Context, Input, Opc, Context.DependentTy,
VK_PRValue, OK_Ordinary, OpLoc, false,
CurFPFeatureOverrides());
CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
ExprResult Fn = CreateUnresolvedLookupExpr(
NamingClass, NestedNameSpecifierLoc(), OpNameInfo, Fns);
if (Fn.isInvalid())
return ExprError();
return CXXOperatorCallExpr::Create(Context, Op, Fn.get(), ArgsArray,
Context.DependentTy, VK_PRValue, OpLoc,
CurFPFeatureOverrides());
}
// Build an empty overload set.
OverloadCandidateSet CandidateSet(OpLoc, OverloadCandidateSet::CSK_Operator);
// Add the candidates from the given function set.
AddNonMemberOperatorCandidates(Fns, ArgsArray, CandidateSet);
// Add operator candidates that are member functions.
AddMemberOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet);
// Add candidates from ADL.
if (PerformADL) {
AddArgumentDependentLookupCandidates(OpName, OpLoc, ArgsArray,
/*ExplicitTemplateArgs*/nullptr,
CandidateSet);
}
// Add builtin operator candidates.
AddBuiltinOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet);
bool HadMultipleCandidates = (CandidateSet.size() > 1);
// Perform overload resolution.
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
case OR_Success: {
// We found a built-in operator or an overloaded operator.
FunctionDecl *FnDecl = Best->Function;
if (FnDecl) {
Expr *Base = nullptr;
// We matched an overloaded operator. Build a call to that
// operator.
// Convert the arguments.
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) {
CheckMemberOperatorAccess(OpLoc, Args[0], nullptr, Best->FoundDecl);
ExprResult InputRes =
PerformObjectArgumentInitialization(Input, /*Qualifier=*/nullptr,
Best->FoundDecl, Method);
if (InputRes.isInvalid())
return ExprError();
Base = Input = InputRes.get();
} else {
// Convert the arguments.
ExprResult InputInit
= PerformCopyInitialization(InitializedEntity::InitializeParameter(
Context,
FnDecl->getParamDecl(0)),
SourceLocation(),
Input);
if (InputInit.isInvalid())
return ExprError();
Input = InputInit.get();
}
// Build the actual expression node.
ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl, Best->FoundDecl,
Base, HadMultipleCandidates,
OpLoc);
if (FnExpr.isInvalid())
return ExprError();
// Determine the result type.
QualType ResultTy = FnDecl->getReturnType();
ExprValueKind VK = Expr::getValueKindForType(ResultTy);
ResultTy = ResultTy.getNonLValueExprType(Context);
Args[0] = Input;
CallExpr *TheCall = CXXOperatorCallExpr::Create(
Context, Op, FnExpr.get(), ArgsArray, ResultTy, VK, OpLoc,
CurFPFeatureOverrides(), Best->IsADLCandidate);
if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall, FnDecl))
return ExprError();
if (CheckFunctionCall(FnDecl, TheCall,
FnDecl->getType()->castAs<FunctionProtoType>()))
return ExprError();
return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall), FnDecl);
} else {
// We matched a built-in operator. Convert the arguments, then
// break out so that we will build the appropriate built-in
// operator node.
ExprResult InputRes = PerformImplicitConversion(
Input, Best->BuiltinParamTypes[0], Best->Conversions[0], AA_Passing,
CCK_ForBuiltinOverloadedOp);
if (InputRes.isInvalid())
return ExprError();
Input = InputRes.get();
break;
}
}
case OR_No_Viable_Function:
// This is an erroneous use of an operator which can be overloaded by
// a non-member function. Check for non-member operators which were
// defined too late to be candidates.
if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, ArgsArray))
// FIXME: Recover by calling the found function.
return ExprError();
// No viable function; fall through to handling this as a
// built-in operator, which will produce an error message for us.
break;
case OR_Ambiguous:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(OpLoc,
PDiag(diag::err_ovl_ambiguous_oper_unary)
<< UnaryOperator::getOpcodeStr(Opc)
<< Input->getType() << Input->getSourceRange()),
*this, OCD_AmbiguousCandidates, ArgsArray,
UnaryOperator::getOpcodeStr(Opc), OpLoc);
return ExprError();
case OR_Deleted:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_deleted_oper)
<< UnaryOperator::getOpcodeStr(Opc)
<< Input->getSourceRange()),
*this, OCD_AllCandidates, ArgsArray, UnaryOperator::getOpcodeStr(Opc),
OpLoc);
return ExprError();
}
// Either we found no viable overloaded operator or we matched a
// built-in operator. In either case, fall through to trying to
// build a built-in operation.
return CreateBuiltinUnaryOp(OpLoc, Opc, Input);
}
/// Perform lookup for an overloaded binary operator.
void Sema::LookupOverloadedBinOp(OverloadCandidateSet &CandidateSet,
OverloadedOperatorKind Op,
const UnresolvedSetImpl &Fns,
ArrayRef<Expr *> Args, bool PerformADL) {
SourceLocation OpLoc = CandidateSet.getLocation();
OverloadedOperatorKind ExtraOp =
CandidateSet.getRewriteInfo().AllowRewrittenCandidates
? getRewrittenOverloadedOperator(Op)
: OO_None;
// Add the candidates from the given function set. This also adds the
// rewritten candidates using these functions if necessary.
AddNonMemberOperatorCandidates(Fns, Args, CandidateSet);
// Add operator candidates that are member functions.
AddMemberOperatorCandidates(Op, OpLoc, Args, CandidateSet);
if (CandidateSet.getRewriteInfo().shouldAddReversed(Op))
AddMemberOperatorCandidates(Op, OpLoc, {Args[1], Args[0]}, CandidateSet,
OverloadCandidateParamOrder::Reversed);
// In C++20, also add any rewritten member candidates.
if (ExtraOp) {
AddMemberOperatorCandidates(ExtraOp, OpLoc, Args, CandidateSet);
if (CandidateSet.getRewriteInfo().shouldAddReversed(ExtraOp))
AddMemberOperatorCandidates(ExtraOp, OpLoc, {Args[1], Args[0]},
CandidateSet,
OverloadCandidateParamOrder::Reversed);
}
// Add candidates from ADL. Per [over.match.oper]p2, this lookup is not
// performed for an assignment operator (nor for operator[] nor operator->,
// which don't get here).
if (Op != OO_Equal && PerformADL) {
DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
AddArgumentDependentLookupCandidates(OpName, OpLoc, Args,
/*ExplicitTemplateArgs*/ nullptr,
CandidateSet);
if (ExtraOp) {
DeclarationName ExtraOpName =
Context.DeclarationNames.getCXXOperatorName(ExtraOp);
AddArgumentDependentLookupCandidates(ExtraOpName, OpLoc, Args,
/*ExplicitTemplateArgs*/ nullptr,
CandidateSet);
}
}
// Add builtin operator candidates.
//
// FIXME: We don't add any rewritten candidates here. This is strictly
// incorrect; a builtin candidate could be hidden by a non-viable candidate,
// resulting in our selecting a rewritten builtin candidate. For example:
//
// enum class E { e };
// bool operator!=(E, E) requires false;
// bool k = E::e != E::e;
//
// ... should select the rewritten builtin candidate 'operator==(E, E)'. But
// it seems unreasonable to consider rewritten builtin candidates. A core
// issue has been filed proposing to removed this requirement.
AddBuiltinOperatorCandidates(Op, OpLoc, Args, CandidateSet);
}
/// Create a binary operation that may resolve to an overloaded
/// operator.
///
/// \param OpLoc The location of the operator itself (e.g., '+').
///
/// \param Opc The BinaryOperatorKind that describes this operator.
///
/// \param Fns The set of non-member functions that will be
/// considered by overload resolution. The caller needs to build this
/// set based on the context using, e.g.,
/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
/// set should not contain any member functions; those will be added
/// by CreateOverloadedBinOp().
///
/// \param LHS Left-hand argument.
/// \param RHS Right-hand argument.
/// \param PerformADL Whether to consider operator candidates found by ADL.
/// \param AllowRewrittenCandidates Whether to consider candidates found by
/// C++20 operator rewrites.
/// \param DefaultedFn If we are synthesizing a defaulted operator function,
/// the function in question. Such a function is never a candidate in
/// our overload resolution. This also enables synthesizing a three-way
/// comparison from < and == as described in C++20 [class.spaceship]p1.
ExprResult Sema::CreateOverloadedBinOp(SourceLocation OpLoc,
BinaryOperatorKind Opc,
const UnresolvedSetImpl &Fns, Expr *LHS,
Expr *RHS, bool PerformADL,
bool AllowRewrittenCandidates,
FunctionDecl *DefaultedFn) {
Expr *Args[2] = { LHS, RHS };
LHS=RHS=nullptr; // Please use only Args instead of LHS/RHS couple
if (!getLangOpts().CPlusPlus20)
AllowRewrittenCandidates = false;
OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc);
// If either side is type-dependent, create an appropriate dependent
// expression.
if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) {
if (Fns.empty()) {
// If there are no functions to store, just build a dependent
// BinaryOperator or CompoundAssignment.
if (BinaryOperator::isCompoundAssignmentOp(Opc))
return CompoundAssignOperator::Create(
Context, Args[0], Args[1], Opc, Context.DependentTy, VK_LValue,
OK_Ordinary, OpLoc, CurFPFeatureOverrides(), Context.DependentTy,
Context.DependentTy);
return BinaryOperator::Create(
Context, Args[0], Args[1], Opc, Context.DependentTy, VK_PRValue,
OK_Ordinary, OpLoc, CurFPFeatureOverrides());
}
// FIXME: save results of ADL from here?
CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
// TODO: provide better source location info in DNLoc component.
DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
DeclarationNameInfo OpNameInfo(OpName, OpLoc);
ExprResult Fn = CreateUnresolvedLookupExpr(
NamingClass, NestedNameSpecifierLoc(), OpNameInfo, Fns, PerformADL);
if (Fn.isInvalid())
return ExprError();
return CXXOperatorCallExpr::Create(Context, Op, Fn.get(), Args,
Context.DependentTy, VK_PRValue, OpLoc,
CurFPFeatureOverrides());
}
// Always do placeholder-like conversions on the RHS.
if (checkPlaceholderForOverload(*this, Args[1]))
return ExprError();
// Do placeholder-like conversion on the LHS; note that we should
// not get here with a PseudoObject LHS.
assert(Args[0]->getObjectKind() != OK_ObjCProperty);
if (checkPlaceholderForOverload(*this, Args[0]))
return ExprError();
// If this is the assignment operator, we only perform overload resolution
// if the left-hand side is a class or enumeration type. This is actually
// a hack. The standard requires that we do overload resolution between the
// various built-in candidates, but as DR507 points out, this can lead to
// problems. So we do it this way, which pretty much follows what GCC does.
// Note that we go the traditional code path for compound assignment forms.
if (Opc == BO_Assign && !Args[0]->getType()->isOverloadableType())
return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
// If this is the .* operator, which is not overloadable, just
// create a built-in binary operator.
if (Opc == BO_PtrMemD)
return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
// Build the overload set.
OverloadCandidateSet CandidateSet(
OpLoc, OverloadCandidateSet::CSK_Operator,
OverloadCandidateSet::OperatorRewriteInfo(Op, AllowRewrittenCandidates));
if (DefaultedFn)
CandidateSet.exclude(DefaultedFn);
LookupOverloadedBinOp(CandidateSet, Op, Fns, Args, PerformADL);
bool HadMultipleCandidates = (CandidateSet.size() > 1);
// Perform overload resolution.
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
case OR_Success: {
// We found a built-in operator or an overloaded operator.
FunctionDecl *FnDecl = Best->Function;
bool IsReversed = Best->isReversed();
if (IsReversed)
std::swap(Args[0], Args[1]);
if (FnDecl) {
Expr *Base = nullptr;
// We matched an overloaded operator. Build a call to that
// operator.
OverloadedOperatorKind ChosenOp =
FnDecl->getDeclName().getCXXOverloadedOperator();
// C++2a [over.match.oper]p9:
// If a rewritten operator== candidate is selected by overload
// resolution for an operator@, its return type shall be cv bool
if (Best->RewriteKind && ChosenOp == OO_EqualEqual &&
!FnDecl->getReturnType()->isBooleanType()) {
bool IsExtension =
FnDecl->getReturnType()->isIntegralOrUnscopedEnumerationType();
Diag(OpLoc, IsExtension ? diag::ext_ovl_rewrite_equalequal_not_bool
: diag::err_ovl_rewrite_equalequal_not_bool)
<< FnDecl->getReturnType() << BinaryOperator::getOpcodeStr(Opc)
<< Args[0]->getSourceRange() << Args[1]->getSourceRange();
Diag(FnDecl->getLocation(), diag::note_declared_at);
if (!IsExtension)
return ExprError();
}
if (AllowRewrittenCandidates && !IsReversed &&
CandidateSet.getRewriteInfo().isReversible()) {
// We could have reversed this operator, but didn't. Check if some
// reversed form was a viable candidate, and if so, if it had a
// better conversion for either parameter. If so, this call is
// formally ambiguous, and allowing it is an extension.
llvm::SmallVector<FunctionDecl*, 4> AmbiguousWith;
for (OverloadCandidate &Cand : CandidateSet) {
if (Cand.Viable && Cand.Function && Cand.isReversed() &&
haveSameParameterTypes(Context, Cand.Function, FnDecl, 2)) {
for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
if (CompareImplicitConversionSequences(
*this, OpLoc, Cand.Conversions[ArgIdx],
Best->Conversions[ArgIdx]) ==
ImplicitConversionSequence::Better) {
AmbiguousWith.push_back(Cand.Function);
break;
}
}
}
}
if (!AmbiguousWith.empty()) {
bool AmbiguousWithSelf =
AmbiguousWith.size() == 1 &&
declaresSameEntity(AmbiguousWith.front(), FnDecl);
Diag(OpLoc, diag::ext_ovl_ambiguous_oper_binary_reversed)
<< BinaryOperator::getOpcodeStr(Opc)
<< Args[0]->getType() << Args[1]->getType() << AmbiguousWithSelf
<< Args[0]->getSourceRange() << Args[1]->getSourceRange();
if (AmbiguousWithSelf) {
Diag(FnDecl->getLocation(),
diag::note_ovl_ambiguous_oper_binary_reversed_self);
} else {
Diag(FnDecl->getLocation(),
diag::note_ovl_ambiguous_oper_binary_selected_candidate);
for (auto *F : AmbiguousWith)
Diag(F->getLocation(),
diag::note_ovl_ambiguous_oper_binary_reversed_candidate);
}
}
}
// Convert the arguments.
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) {
// Best->Access is only meaningful for class members.
CheckMemberOperatorAccess(OpLoc, Args[0], Args[1], Best->FoundDecl);
ExprResult Arg1 =
PerformCopyInitialization(
InitializedEntity::InitializeParameter(Context,
FnDecl->getParamDecl(0)),
SourceLocation(), Args[1]);
if (Arg1.isInvalid())
return ExprError();
ExprResult Arg0 =
PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr,
Best->FoundDecl, Method);
if (Arg0.isInvalid())
return ExprError();
Base = Args[0] = Arg0.getAs<Expr>();
Args[1] = RHS = Arg1.getAs<Expr>();
} else {
// Convert the arguments.
ExprResult Arg0 = PerformCopyInitialization(
InitializedEntity::InitializeParameter(Context,
FnDecl->getParamDecl(0)),
SourceLocation(), Args[0]);
if (Arg0.isInvalid())
return ExprError();
ExprResult Arg1 =
PerformCopyInitialization(
InitializedEntity::InitializeParameter(Context,
FnDecl->getParamDecl(1)),
SourceLocation(), Args[1]);
if (Arg1.isInvalid())
return ExprError();
Args[0] = LHS = Arg0.getAs<Expr>();
Args[1] = RHS = Arg1.getAs<Expr>();
}
// Build the actual expression node.
ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl,
Best->FoundDecl, Base,
HadMultipleCandidates, OpLoc);
if (FnExpr.isInvalid())
return ExprError();
// Determine the result type.
QualType ResultTy = FnDecl->getReturnType();
ExprValueKind VK = Expr::getValueKindForType(ResultTy);
ResultTy = ResultTy.getNonLValueExprType(Context);
CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
Context, ChosenOp, FnExpr.get(), Args, ResultTy, VK, OpLoc,
CurFPFeatureOverrides(), Best->IsADLCandidate);
if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall,
FnDecl))
return ExprError();
ArrayRef<const Expr *> ArgsArray(Args, 2);
const Expr *ImplicitThis = nullptr;
// Cut off the implicit 'this'.
if (isa<CXXMethodDecl>(FnDecl)) {
ImplicitThis = ArgsArray[0];
ArgsArray = ArgsArray.slice(1);
}
// Check for a self move.
if (Op == OO_Equal)
DiagnoseSelfMove(Args[0], Args[1], OpLoc);
if (ImplicitThis) {
QualType ThisType = Context.getPointerType(ImplicitThis->getType());
QualType ThisTypeFromDecl = Context.getPointerType(
cast<CXXMethodDecl>(FnDecl)->getThisObjectType());
CheckArgAlignment(OpLoc, FnDecl, "'this'", ThisType,
ThisTypeFromDecl);
}
checkCall(FnDecl, nullptr, ImplicitThis, ArgsArray,
isa<CXXMethodDecl>(FnDecl), OpLoc, TheCall->getSourceRange(),
VariadicDoesNotApply);
ExprResult R = MaybeBindToTemporary(TheCall);
if (R.isInvalid())
return ExprError();
R = CheckForImmediateInvocation(R, FnDecl);
if (R.isInvalid())
return ExprError();
// For a rewritten candidate, we've already reversed the arguments
// if needed. Perform the rest of the rewrite now.
if ((Best->RewriteKind & CRK_DifferentOperator) ||
(Op == OO_Spaceship && IsReversed)) {
if (Op == OO_ExclaimEqual) {
assert(ChosenOp == OO_EqualEqual && "unexpected operator name");
R = CreateBuiltinUnaryOp(OpLoc, UO_LNot, R.get());
} else {
assert(ChosenOp == OO_Spaceship && "unexpected operator name");
llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false);
Expr *ZeroLiteral =
IntegerLiteral::Create(Context, Zero, Context.IntTy, OpLoc);
Sema::CodeSynthesisContext Ctx;
Ctx.Kind = Sema::CodeSynthesisContext::RewritingOperatorAsSpaceship;
Ctx.Entity = FnDecl;
pushCodeSynthesisContext(Ctx);
R = CreateOverloadedBinOp(
OpLoc, Opc, Fns, IsReversed ? ZeroLiteral : R.get(),
IsReversed ? R.get() : ZeroLiteral, PerformADL,
/*AllowRewrittenCandidates=*/false);
popCodeSynthesisContext();
}
if (R.isInvalid())
return ExprError();
} else {
assert(ChosenOp == Op && "unexpected operator name");
}
// Make a note in the AST if we did any rewriting.
if (Best->RewriteKind != CRK_None)
R = new (Context) CXXRewrittenBinaryOperator(R.get(), IsReversed);
return R;
} else {
// We matched a built-in operator. Convert the arguments, then
// break out so that we will build the appropriate built-in
// operator node.
ExprResult ArgsRes0 = PerformImplicitConversion(
Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0],
AA_Passing, CCK_ForBuiltinOverloadedOp);
if (ArgsRes0.isInvalid())
return ExprError();
Args[0] = ArgsRes0.get();
ExprResult ArgsRes1 = PerformImplicitConversion(
Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1],
AA_Passing, CCK_ForBuiltinOverloadedOp);
if (ArgsRes1.isInvalid())
return ExprError();
Args[1] = ArgsRes1.get();
break;
}
}
case OR_No_Viable_Function: {
// C++ [over.match.oper]p9:
// If the operator is the operator , [...] and there are no
// viable functions, then the operator is assumed to be the
// built-in operator and interpreted according to clause 5.
if (Opc == BO_Comma)
break;
// When defaulting an 'operator<=>', we can try to synthesize a three-way
// compare result using '==' and '<'.
if (DefaultedFn && Opc == BO_Cmp) {
ExprResult E = BuildSynthesizedThreeWayComparison(OpLoc, Fns, Args[0],
Args[1], DefaultedFn);
if (E.isInvalid() || E.isUsable())
return E;
}
// For class as left operand for assignment or compound assignment
// operator do not fall through to handling in built-in, but report that
// no overloaded assignment operator found
ExprResult Result = ExprError();
StringRef OpcStr = BinaryOperator::getOpcodeStr(Opc);
auto Cands = CandidateSet.CompleteCandidates(*this, OCD_AllCandidates,
Args, OpLoc);
DeferDiagsRAII DDR(*this,
CandidateSet.shouldDeferDiags(*this, Args, OpLoc));
if (Args[0]->getType()->isRecordType() &&
Opc >= BO_Assign && Opc <= BO_OrAssign) {
Diag(OpLoc, diag::err_ovl_no_viable_oper)
<< BinaryOperator::getOpcodeStr(Opc)
<< Args[0]->getSourceRange() << Args[1]->getSourceRange();
if (Args[0]->getType()->isIncompleteType()) {
Diag(OpLoc, diag::note_assign_lhs_incomplete)
<< Args[0]->getType()
<< Args[0]->getSourceRange() << Args[1]->getSourceRange();
}
} else {
// This is an erroneous use of an operator which can be overloaded by
// a non-member function. Check for non-member operators which were
// defined too late to be candidates.
if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, Args))
// FIXME: Recover by calling the found function.
return ExprError();
// No viable function; try to create a built-in operation, which will
// produce an error. Then, show the non-viable candidates.
Result = CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
}
assert(Result.isInvalid() &&
"C++ binary operator overloading is missing candidates!");
CandidateSet.NoteCandidates(*this, Args, Cands, OpcStr, OpLoc);
return Result;
}
case OR_Ambiguous:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_ambiguous_oper_binary)
<< BinaryOperator::getOpcodeStr(Opc)
<< Args[0]->getType()
<< Args[1]->getType()
<< Args[0]->getSourceRange()
<< Args[1]->getSourceRange()),
*this, OCD_AmbiguousCandidates, Args, BinaryOperator::getOpcodeStr(Opc),
OpLoc);
return ExprError();
case OR_Deleted:
if (isImplicitlyDeleted(Best->Function)) {
FunctionDecl *DeletedFD = Best->Function;
DefaultedFunctionKind DFK = getDefaultedFunctionKind(DeletedFD);
if (DFK.isSpecialMember()) {
Diag(OpLoc, diag::err_ovl_deleted_special_oper)
<< Args[0]->getType() << DFK.asSpecialMember();
} else {
assert(DFK.isComparison());
Diag(OpLoc, diag::err_ovl_deleted_comparison)
<< Args[0]->getType() << DeletedFD;
}
// The user probably meant to call this special member. Just
// explain why it's deleted.
NoteDeletedFunction(DeletedFD);
return ExprError();
}
CandidateSet.NoteCandidates(
PartialDiagnosticAt(
OpLoc, PDiag(diag::err_ovl_deleted_oper)
<< getOperatorSpelling(Best->Function->getDeclName()
.getCXXOverloadedOperator())
<< Args[0]->getSourceRange()
<< Args[1]->getSourceRange()),
*this, OCD_AllCandidates, Args, BinaryOperator::getOpcodeStr(Opc),
OpLoc);
return ExprError();
}
// We matched a built-in operator; build it.
return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
}
ExprResult Sema::BuildSynthesizedThreeWayComparison(
SourceLocation OpLoc, const UnresolvedSetImpl &Fns, Expr *LHS, Expr *RHS,
FunctionDecl *DefaultedFn) {
const ComparisonCategoryInfo *Info =
Context.CompCategories.lookupInfoForType(DefaultedFn->getReturnType());
// If we're not producing a known comparison category type, we can't
// synthesize a three-way comparison. Let the caller diagnose this.
if (!Info)
return ExprResult((Expr*)nullptr);
// If we ever want to perform this synthesis more generally, we will need to
// apply the temporary materialization conversion to the operands.
assert(LHS->isGLValue() && RHS->isGLValue() &&
"cannot use prvalue expressions more than once");
Expr *OrigLHS = LHS;
Expr *OrigRHS = RHS;
// Replace the LHS and RHS with OpaqueValueExprs; we're going to refer to
// each of them multiple times below.
LHS = new (Context)
OpaqueValueExpr(LHS->getExprLoc(), LHS->getType(), LHS->getValueKind(),
LHS->getObjectKind(), LHS);
RHS = new (Context)
OpaqueValueExpr(RHS->getExprLoc(), RHS->getType(), RHS->getValueKind(),
RHS->getObjectKind(), RHS);
ExprResult Eq = CreateOverloadedBinOp(OpLoc, BO_EQ, Fns, LHS, RHS, true, true,
DefaultedFn);
if (Eq.isInvalid())
return ExprError();
ExprResult Less = CreateOverloadedBinOp(OpLoc, BO_LT, Fns, LHS, RHS, true,
true, DefaultedFn);
if (Less.isInvalid())
return ExprError();
ExprResult Greater;
if (Info->isPartial()) {
Greater = CreateOverloadedBinOp(OpLoc, BO_LT, Fns, RHS, LHS, true, true,
DefaultedFn);
if (Greater.isInvalid())
return ExprError();
}
// Form the list of comparisons we're going to perform.
struct Comparison {
ExprResult Cmp;
ComparisonCategoryResult Result;
} Comparisons[4] =
{ {Eq, Info->isStrong() ? ComparisonCategoryResult::Equal
: ComparisonCategoryResult::Equivalent},
{Less, ComparisonCategoryResult::Less},
{Greater, ComparisonCategoryResult::Greater},
{ExprResult(), ComparisonCategoryResult::Unordered},
};
int I = Info->isPartial() ? 3 : 2;
// Combine the comparisons with suitable conditional expressions.
ExprResult Result;
for (; I >= 0; --I) {
// Build a reference to the comparison category constant.
auto *VI = Info->lookupValueInfo(Comparisons[I].Result);
// FIXME: Missing a constant for a comparison category. Diagnose this?
if (!VI)
return ExprResult((Expr*)nullptr);
ExprResult ThisResult =
BuildDeclarationNameExpr(CXXScopeSpec(), DeclarationNameInfo(), VI->VD);
if (ThisResult.isInvalid())
return ExprError();
// Build a conditional unless this is the final case.
if (Result.get()) {
Result = ActOnConditionalOp(OpLoc, OpLoc, Comparisons[I].Cmp.get(),
ThisResult.get(), Result.get());
if (Result.isInvalid())
return ExprError();
} else {
Result = ThisResult;
}
}
// Build a PseudoObjectExpr to model the rewriting of an <=> operator, and to
// bind the OpaqueValueExprs before they're (repeatedly) used.
Expr *SyntacticForm = BinaryOperator::Create(
Context, OrigLHS, OrigRHS, BO_Cmp, Result.get()->getType(),
Result.get()->getValueKind(), Result.get()->getObjectKind(), OpLoc,
CurFPFeatureOverrides());
Expr *SemanticForm[] = {LHS, RHS, Result.get()};
return PseudoObjectExpr::Create(Context, SyntacticForm, SemanticForm, 2);
}
ExprResult
Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
SourceLocation RLoc,
Expr *Base, Expr *Idx) {
Expr *Args[2] = { Base, Idx };
DeclarationName OpName =
Context.DeclarationNames.getCXXOperatorName(OO_Subscript);
// If either side is type-dependent, create an appropriate dependent
// expression.
if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) {
CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
// CHECKME: no 'operator' keyword?
DeclarationNameInfo OpNameInfo(OpName, LLoc);
OpNameInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc));
ExprResult Fn = CreateUnresolvedLookupExpr(
NamingClass, NestedNameSpecifierLoc(), OpNameInfo, UnresolvedSet<0>());
if (Fn.isInvalid())
return ExprError();
// Can't add any actual overloads yet
return CXXOperatorCallExpr::Create(Context, OO_Subscript, Fn.get(), Args,
Context.DependentTy, VK_PRValue, RLoc,
CurFPFeatureOverrides());
}
// Handle placeholders on both operands.
if (checkPlaceholderForOverload(*this, Args[0]))
return ExprError();
if (checkPlaceholderForOverload(*this, Args[1]))
return ExprError();
// Build an empty overload set.
OverloadCandidateSet CandidateSet(LLoc, OverloadCandidateSet::CSK_Operator);
// Subscript can only be overloaded as a member function.
// Add operator candidates that are member functions.
AddMemberOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet);
// Add builtin operator candidates.
AddBuiltinOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet);
bool HadMultipleCandidates = (CandidateSet.size() > 1);
// Perform overload resolution.
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(*this, LLoc, Best)) {
case OR_Success: {
// We found a built-in operator or an overloaded operator.
FunctionDecl *FnDecl = Best->Function;
if (FnDecl) {
// We matched an overloaded operator. Build a call to that
// operator.
CheckMemberOperatorAccess(LLoc, Args[0], Args[1], Best->FoundDecl);
// Convert the arguments.
CXXMethodDecl *Method = cast<CXXMethodDecl>(FnDecl);
ExprResult Arg0 =
PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr,
Best->FoundDecl, Method);
if (Arg0.isInvalid())
return ExprError();
Args[0] = Arg0.get();
// Convert the arguments.
ExprResult InputInit
= PerformCopyInitialization(InitializedEntity::InitializeParameter(
Context,
FnDecl->getParamDecl(0)),
SourceLocation(),
Args[1]);
if (InputInit.isInvalid())
return ExprError();
Args[1] = InputInit.getAs<Expr>();
// Build the actual expression node.
DeclarationNameInfo OpLocInfo(OpName, LLoc);
OpLocInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc));
ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl,
Best->FoundDecl,
Base,
HadMultipleCandidates,
OpLocInfo.getLoc(),
OpLocInfo.getInfo());
if (FnExpr.isInvalid())
return ExprError();
// Determine the result type
QualType ResultTy = FnDecl->getReturnType();
ExprValueKind VK = Expr::getValueKindForType(ResultTy);
ResultTy = ResultTy.getNonLValueExprType(Context);
CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
Context, OO_Subscript, FnExpr.get(), Args, ResultTy, VK, RLoc,
CurFPFeatureOverrides());
if (CheckCallReturnType(FnDecl->getReturnType(), LLoc, TheCall, FnDecl))
return ExprError();
if (CheckFunctionCall(Method, TheCall,
Method->getType()->castAs<FunctionProtoType>()))
return ExprError();
return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall),
FnDecl);
} else {
// We matched a built-in operator. Convert the arguments, then
// break out so that we will build the appropriate built-in
// operator node.
ExprResult ArgsRes0 = PerformImplicitConversion(
Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0],
AA_Passing, CCK_ForBuiltinOverloadedOp);
if (ArgsRes0.isInvalid())
return ExprError();
Args[0] = ArgsRes0.get();
ExprResult ArgsRes1 = PerformImplicitConversion(
Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1],
AA_Passing, CCK_ForBuiltinOverloadedOp);
if (ArgsRes1.isInvalid())
return ExprError();
Args[1] = ArgsRes1.get();
break;
}
}
case OR_No_Viable_Function: {
PartialDiagnostic PD = CandidateSet.empty()
? (PDiag(diag::err_ovl_no_oper)
<< Args[0]->getType() << /*subscript*/ 0
<< Args[0]->getSourceRange() << Args[1]->getSourceRange())
: (PDiag(diag::err_ovl_no_viable_subscript)
<< Args[0]->getType() << Args[0]->getSourceRange()
<< Args[1]->getSourceRange());
CandidateSet.NoteCandidates(PartialDiagnosticAt(LLoc, PD), *this,
OCD_AllCandidates, Args, "[]", LLoc);
return ExprError();
}
case OR_Ambiguous:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(LLoc, PDiag(diag::err_ovl_ambiguous_oper_binary)
<< "[]" << Args[0]->getType()
<< Args[1]->getType()
<< Args[0]->getSourceRange()
<< Args[1]->getSourceRange()),
*this, OCD_AmbiguousCandidates, Args, "[]", LLoc);
return ExprError();
case OR_Deleted:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(LLoc, PDiag(diag::err_ovl_deleted_oper)
<< "[]" << Args[0]->getSourceRange()
<< Args[1]->getSourceRange()),
*this, OCD_AllCandidates, Args, "[]", LLoc);
return ExprError();
}
// We matched a built-in operator; build it.
return CreateBuiltinArraySubscriptExpr(Args[0], LLoc, Args[1], RLoc);
}
/// BuildCallToMemberFunction - Build a call to a member
/// function. MemExpr is the expression that refers to the member
/// function (and includes the object parameter), Args/NumArgs are the
/// arguments to the function call (not including the object
/// parameter). The caller needs to validate that the member
/// expression refers to a non-static member function or an overloaded
/// member function.
ExprResult Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE,
SourceLocation LParenLoc,
MultiExprArg Args,
SourceLocation RParenLoc,
Expr *ExecConfig, bool IsExecConfig,
bool AllowRecovery) {
assert(MemExprE->getType() == Context.BoundMemberTy ||
MemExprE->getType() == Context.OverloadTy);
// Dig out the member expression. This holds both the object
// argument and the member function we're referring to.
Expr *NakedMemExpr = MemExprE->IgnoreParens();
// Determine whether this is a call to a pointer-to-member function.
if (BinaryOperator *op = dyn_cast<BinaryOperator>(NakedMemExpr)) {
assert(op->getType() == Context.BoundMemberTy);
assert(op->getOpcode() == BO_PtrMemD || op->getOpcode() == BO_PtrMemI);
QualType fnType =
op->getRHS()->getType()->castAs<MemberPointerType>()->getPointeeType();
const FunctionProtoType *proto = fnType->castAs<FunctionProtoType>();
QualType resultType = proto->getCallResultType(Context);
ExprValueKind valueKind = Expr::getValueKindForType(proto->getReturnType());
// Check that the object type isn't more qualified than the
// member function we're calling.
Qualifiers funcQuals = proto->getMethodQuals();
QualType objectType = op->getLHS()->getType();
if (op->getOpcode() == BO_PtrMemI)
objectType = objectType->castAs<PointerType>()->getPointeeType();
Qualifiers objectQuals = objectType.getQualifiers();
Qualifiers difference = objectQuals - funcQuals;
difference.removeObjCGCAttr();
difference.removeAddressSpace();
if (difference) {
std::string qualsString = difference.getAsString();
Diag(LParenLoc, diag::err_pointer_to_member_call_drops_quals)
<< fnType.getUnqualifiedType()
<< qualsString
<< (qualsString.find(' ') == std::string::npos ? 1 : 2);
}
CXXMemberCallExpr *call = CXXMemberCallExpr::Create(
Context, MemExprE, Args, resultType, valueKind, RParenLoc,
CurFPFeatureOverrides(), proto->getNumParams());
if (CheckCallReturnType(proto->getReturnType(), op->getRHS()->getBeginLoc(),
call, nullptr))
return ExprError();
if (ConvertArgumentsForCall(call, op, nullptr, proto, Args, RParenLoc))
return ExprError();
if (CheckOtherCall(call, proto))
return ExprError();
return MaybeBindToTemporary(call);
}
// We only try to build a recovery expr at this level if we can preserve
// the return type, otherwise we return ExprError() and let the caller
// recover.
auto BuildRecoveryExpr = [&](QualType Type) {
if (!AllowRecovery)
return ExprError();
std::vector<Expr *> SubExprs = {MemExprE};
llvm::for_each(Args, [&SubExprs](Expr *E) { SubExprs.push_back(E); });
return CreateRecoveryExpr(MemExprE->getBeginLoc(), RParenLoc, SubExprs,
Type);
};
if (isa<CXXPseudoDestructorExpr>(NakedMemExpr))
return CallExpr::Create(Context, MemExprE, Args, Context.VoidTy, VK_PRValue,
RParenLoc, CurFPFeatureOverrides());
UnbridgedCastsSet UnbridgedCasts;
if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts))
return ExprError();
MemberExpr *MemExpr;
CXXMethodDecl *Method = nullptr;
DeclAccessPair FoundDecl = DeclAccessPair::make(nullptr, AS_public);
NestedNameSpecifier *Qualifier = nullptr;
if (isa<MemberExpr>(NakedMemExpr)) {
MemExpr = cast<MemberExpr>(NakedMemExpr);
Method = cast<CXXMethodDecl>(MemExpr->getMemberDecl());
FoundDecl = MemExpr->getFoundDecl();
Qualifier = MemExpr->getQualifier();
UnbridgedCasts.restore();
} else {
UnresolvedMemberExpr *UnresExpr = cast<UnresolvedMemberExpr>(NakedMemExpr);
Qualifier = UnresExpr->getQualifier();
QualType ObjectType = UnresExpr->getBaseType();
Expr::Classification ObjectClassification
= UnresExpr->isArrow()? Expr::Classification::makeSimpleLValue()
: UnresExpr->getBase()->Classify(Context);
// Add overload candidates
OverloadCandidateSet CandidateSet(UnresExpr->getMemberLoc(),
OverloadCandidateSet::CSK_Normal);
// FIXME: avoid copy.
TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
if (UnresExpr->hasExplicitTemplateArgs()) {
UnresExpr->copyTemplateArgumentsInto(TemplateArgsBuffer);
TemplateArgs = &TemplateArgsBuffer;
}
for (UnresolvedMemberExpr::decls_iterator I = UnresExpr->decls_begin(),
E = UnresExpr->decls_end(); I != E; ++I) {
NamedDecl *Func = *I;
CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(Func->getDeclContext());
if (isa<UsingShadowDecl>(Func))
Func = cast<UsingShadowDecl>(Func)->getTargetDecl();
// Microsoft supports direct constructor calls.
if (getLangOpts().MicrosoftExt && isa<CXXConstructorDecl>(Func)) {
AddOverloadCandidate(cast<CXXConstructorDecl>(Func), I.getPair(), Args,
CandidateSet,
/*SuppressUserConversions*/ false);
} else if ((Method = dyn_cast<CXXMethodDecl>(Func))) {
// If explicit template arguments were provided, we can't call a
// non-template member function.
if (TemplateArgs)
continue;
AddMethodCandidate(Method, I.getPair(), ActingDC, ObjectType,
ObjectClassification, Args, CandidateSet,
/*SuppressUserConversions=*/false);
} else {
AddMethodTemplateCandidate(
cast<FunctionTemplateDecl>(Func), I.getPair(), ActingDC,
TemplateArgs, ObjectType, ObjectClassification, Args, CandidateSet,
/*SuppressUserConversions=*/false);
}
}
DeclarationName DeclName = UnresExpr->getMemberName();
UnbridgedCasts.restore();
OverloadCandidateSet::iterator Best;
bool Succeeded = false;
switch (CandidateSet.BestViableFunction(*this, UnresExpr->getBeginLoc(),
Best)) {
case OR_Success:
Method = cast<CXXMethodDecl>(Best->Function);
FoundDecl = Best->FoundDecl;
CheckUnresolvedMemberAccess(UnresExpr, Best->FoundDecl);
if (DiagnoseUseOfDecl(Best->FoundDecl, UnresExpr->getNameLoc()))
break;
// If FoundDecl is different from Method (such as if one is a template
// and the other a specialization), make sure DiagnoseUseOfDecl is
// called on both.
// FIXME: This would be more comprehensively addressed by modifying
// DiagnoseUseOfDecl to accept both the FoundDecl and the decl
// being used.
if (Method != FoundDecl.getDecl() &&
DiagnoseUseOfDecl(Method, UnresExpr->getNameLoc()))
break;
Succeeded = true;
break;
case OR_No_Viable_Function:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(
UnresExpr->getMemberLoc(),
PDiag(diag::err_ovl_no_viable_member_function_in_call)
<< DeclName << MemExprE->getSourceRange()),
*this, OCD_AllCandidates, Args);
break;
case OR_Ambiguous:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(UnresExpr->getMemberLoc(),
PDiag(diag::err_ovl_ambiguous_member_call)
<< DeclName << MemExprE->getSourceRange()),
*this, OCD_AmbiguousCandidates, Args);
break;
case OR_Deleted:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(UnresExpr->getMemberLoc(),
PDiag(diag::err_ovl_deleted_member_call)
<< DeclName << MemExprE->getSourceRange()),
*this, OCD_AllCandidates, Args);
break;
}
// Overload resolution fails, try to recover.
if (!Succeeded)
return BuildRecoveryExpr(chooseRecoveryType(CandidateSet, &Best));
MemExprE = FixOverloadedFunctionReference(MemExprE, FoundDecl, Method);
// If overload resolution picked a static member, build a
// non-member call based on that function.
if (Method->isStatic()) {
return BuildResolvedCallExpr(MemExprE, Method, LParenLoc, Args, RParenLoc,
ExecConfig, IsExecConfig);
}
MemExpr = cast<MemberExpr>(MemExprE->IgnoreParens());
}
QualType ResultType = Method->getReturnType();
ExprValueKind VK = Expr::getValueKindForType(ResultType);
ResultType = ResultType.getNonLValueExprType(Context);
assert(Method && "Member call to something that isn't a method?");
const auto *Proto = Method->getType()->castAs<FunctionProtoType>();
CXXMemberCallExpr *TheCall = CXXMemberCallExpr::Create(
Context, MemExprE, Args, ResultType, VK, RParenLoc,
CurFPFeatureOverrides(), Proto->getNumParams());
// Check for a valid return type.
if (CheckCallReturnType(Method->getReturnType(), MemExpr->getMemberLoc(),
TheCall, Method))
return BuildRecoveryExpr(ResultType);
// Convert the object argument (for a non-static member function call).
// We only need to do this if there was actually an overload; otherwise
// it was done at lookup.
if (!Method->isStatic()) {
ExprResult ObjectArg =
PerformObjectArgumentInitialization(MemExpr->getBase(), Qualifier,
FoundDecl, Method);
if (ObjectArg.isInvalid())
return ExprError();
MemExpr->setBase(ObjectArg.get());
}
// Convert the rest of the arguments
if (ConvertArgumentsForCall(TheCall, MemExpr, Method, Proto, Args,
RParenLoc))
return BuildRecoveryExpr(ResultType);
DiagnoseSentinelCalls(Method, LParenLoc, Args);
if (CheckFunctionCall(Method, TheCall, Proto))
return ExprError();
// In the case the method to call was not selected by the overloading
// resolution process, we still need to handle the enable_if attribute. Do
// that here, so it will not hide previous -- and more relevant -- errors.
if (auto *MemE = dyn_cast<MemberExpr>(NakedMemExpr)) {
if (const EnableIfAttr *Attr =
CheckEnableIf(Method, LParenLoc, Args, true)) {
Diag(MemE->getMemberLoc(),
diag::err_ovl_no_viable_member_function_in_call)
<< Method << Method->getSourceRange();
Diag(Method->getLocation(),
diag::note_ovl_candidate_disabled_by_function_cond_attr)
<< Attr->getCond()->getSourceRange() << Attr->getMessage();
return ExprError();
}
}
if ((isa<CXXConstructorDecl>(CurContext) ||
isa<CXXDestructorDecl>(CurContext)) &&
TheCall->getMethodDecl()->isPure()) {
const CXXMethodDecl *MD = TheCall->getMethodDecl();
if (isa<CXXThisExpr>(MemExpr->getBase()->IgnoreParenCasts()) &&
MemExpr->performsVirtualDispatch(getLangOpts())) {
Diag(MemExpr->getBeginLoc(),
diag::warn_call_to_pure_virtual_member_function_from_ctor_dtor)
<< MD->getDeclName() << isa<CXXDestructorDecl>(CurContext)
<< MD->getParent();
Diag(MD->getBeginLoc(), diag::note_previous_decl) << MD->getDeclName();
if (getLangOpts().AppleKext)
Diag(MemExpr->getBeginLoc(), diag::note_pure_qualified_call_kext)
<< MD->getParent() << MD->getDeclName();
}
}
if (CXXDestructorDecl *DD =
dyn_cast<CXXDestructorDecl>(TheCall->getMethodDecl())) {
// a->A::f() doesn't go through the vtable, except in AppleKext mode.
bool CallCanBeVirtual = !MemExpr->hasQualifier() || getLangOpts().AppleKext;
CheckVirtualDtorCall(DD, MemExpr->getBeginLoc(), /*IsDelete=*/false,
CallCanBeVirtual, /*WarnOnNonAbstractTypes=*/true,
MemExpr->getMemberLoc());
}
return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall),
TheCall->getMethodDecl());
}
/// BuildCallToObjectOfClassType - Build a call to an object of class
/// type (C++ [over.call.object]), which can end up invoking an
/// overloaded function call operator (@c operator()) or performing a
/// user-defined conversion on the object argument.
ExprResult
Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Obj,
SourceLocation LParenLoc,
MultiExprArg Args,
SourceLocation RParenLoc) {
if (checkPlaceholderForOverload(*this, Obj))
return ExprError();
ExprResult Object = Obj;
UnbridgedCastsSet UnbridgedCasts;
if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts))
return ExprError();
assert(Object.get()->getType()->isRecordType() &&
"Requires object type argument");
// C++ [over.call.object]p1:
// If the primary-expression E in the function call syntax
// evaluates to a class object of type "cv T", then the set of
// candidate functions includes at least the function call
// operators of T. The function call operators of T are obtained by
// ordinary lookup of the name operator() in the context of
// (E).operator().
OverloadCandidateSet CandidateSet(LParenLoc,
OverloadCandidateSet::CSK_Operator);
DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call);
if (RequireCompleteType(LParenLoc, Object.get()->getType(),
diag::err_incomplete_object_call, Object.get()))
return true;
const auto *Record = Object.get()->getType()->castAs<RecordType>();
LookupResult R(*this, OpName, LParenLoc, LookupOrdinaryName);
LookupQualifiedName(R, Record->getDecl());
R.suppressDiagnostics();
for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end();
Oper != OperEnd; ++Oper) {
AddMethodCandidate(Oper.getPair(), Object.get()->getType(),
Object.get()->Classify(Context), Args, CandidateSet,
/*SuppressUserConversion=*/false);
}
// C++ [over.call.object]p2:
// In addition, for each (non-explicit in C++0x) conversion function
// declared in T of the form
//
// operator conversion-type-id () cv-qualifier;
//
// where cv-qualifier is the same cv-qualification as, or a
// greater cv-qualification than, cv, and where conversion-type-id
// denotes the type "pointer to function of (P1,...,Pn) returning
// R", or the type "reference to pointer to function of
// (P1,...,Pn) returning R", or the type "reference to function
// of (P1,...,Pn) returning R", a surrogate call function [...]
// is also considered as a candidate function. Similarly,
// surrogate call functions are added to the set of candidate
// functions for each conversion function declared in an
// accessible base class provided the function is not hidden
// within T by another intervening declaration.
const auto &Conversions =
cast<CXXRecordDecl>(Record->getDecl())->getVisibleConversionFunctions();
for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
NamedDecl *D = *I;
CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
if (isa<UsingShadowDecl>(D))
D = cast<UsingShadowDecl>(D)->getTargetDecl();
// Skip over templated conversion functions; they aren't
// surrogates.
if (isa<FunctionTemplateDecl>(D))
continue;
CXXConversionDecl *Conv = cast<CXXConversionDecl>(D);
if (!Conv->isExplicit()) {
// Strip the reference type (if any) and then the pointer type (if
// any) to get down to what might be a function type.
QualType ConvType = Conv->getConversionType().getNonReferenceType();
if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>())
ConvType = ConvPtrType->getPointeeType();
if (const FunctionProtoType *Proto = ConvType->getAs<FunctionProtoType>())
{
AddSurrogateCandidate(Conv, I.getPair(), ActingContext, Proto,
Object.get(), Args, CandidateSet);
}
}
}
bool HadMultipleCandidates = (CandidateSet.size() > 1);
// Perform overload resolution.
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(*this, Object.get()->getBeginLoc(),
Best)) {
case OR_Success:
// Overload resolution succeeded; we'll build the appropriate call
// below.
break;
case OR_No_Viable_Function: {
PartialDiagnostic PD =
CandidateSet.empty()
? (PDiag(diag::err_ovl_no_oper)
<< Object.get()->getType() << /*call*/ 1
<< Object.get()->getSourceRange())
: (PDiag(diag::err_ovl_no_viable_object_call)
<< Object.get()->getType() << Object.get()->getSourceRange());
CandidateSet.NoteCandidates(
PartialDiagnosticAt(Object.get()->getBeginLoc(), PD), *this,
OCD_AllCandidates, Args);
break;
}
case OR_Ambiguous:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(Object.get()->getBeginLoc(),
PDiag(diag::err_ovl_ambiguous_object_call)
<< Object.get()->getType()
<< Object.get()->getSourceRange()),
*this, OCD_AmbiguousCandidates, Args);
break;
case OR_Deleted:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(Object.get()->getBeginLoc(),
PDiag(diag::err_ovl_deleted_object_call)
<< Object.get()->getType()
<< Object.get()->getSourceRange()),
*this, OCD_AllCandidates, Args);
break;
}
if (Best == CandidateSet.end())
return true;
UnbridgedCasts.restore();
if (Best->Function == nullptr) {
// Since there is no function declaration, this is one of the
// surrogate candidates. Dig out the conversion function.
CXXConversionDecl *Conv
= cast<CXXConversionDecl>(
Best->Conversions[0].UserDefined.ConversionFunction);
CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr,
Best->FoundDecl);
if (DiagnoseUseOfDecl(Best->FoundDecl, LParenLoc))
return ExprError();
assert(Conv == Best->FoundDecl.getDecl() &&
"Found Decl & conversion-to-functionptr should be same, right?!");
// We selected one of the surrogate functions that converts the
// object parameter to a function pointer. Perform the conversion
// on the object argument, then let BuildCallExpr finish the job.
// Create an implicit member expr to refer to the conversion operator.
// and then call it.
ExprResult Call = BuildCXXMemberCallExpr(Object.get(), Best->FoundDecl,
Conv, HadMultipleCandidates);
if (Call.isInvalid())
return ExprError();
// Record usage of conversion in an implicit cast.
Call = ImplicitCastExpr::Create(
Context, Call.get()->getType(), CK_UserDefinedConversion, Call.get(),
nullptr, VK_PRValue, CurFPFeatureOverrides());
return BuildCallExpr(S, Call.get(), LParenLoc, Args, RParenLoc);
}
CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr, Best->FoundDecl);
// We found an overloaded operator(). Build a CXXOperatorCallExpr
// that calls this method, using Object for the implicit object
// parameter and passing along the remaining arguments.
CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function);
// An error diagnostic has already been printed when parsing the declaration.
if (Method->isInvalidDecl())
return ExprError();
const auto *Proto = Method->getType()->castAs<FunctionProtoType>();
unsigned NumParams = Proto->getNumParams();
DeclarationNameInfo OpLocInfo(
Context.DeclarationNames.getCXXOperatorName(OO_Call), LParenLoc);
OpLocInfo.setCXXOperatorNameRange(SourceRange(LParenLoc, RParenLoc));
ExprResult NewFn = CreateFunctionRefExpr(*this, Method, Best->FoundDecl,
Obj, HadMultipleCandidates,
OpLocInfo.getLoc(),
OpLocInfo.getInfo());
if (NewFn.isInvalid())
return true;
// The number of argument slots to allocate in the call. If we have default
// arguments we need to allocate space for them as well. We additionally
// need one more slot for the object parameter.
unsigned NumArgsSlots = 1 + std::max<unsigned>(Args.size(), NumParams);
// Build the full argument list for the method call (the implicit object
// parameter is placed at the beginning of the list).
SmallVector<Expr *, 8> MethodArgs(NumArgsSlots);
bool IsError = false;
// Initialize the implicit object parameter.
ExprResult ObjRes =
PerformObjectArgumentInitialization(Object.get(), /*Qualifier=*/nullptr,
Best->FoundDecl, Method);
if (ObjRes.isInvalid())
IsError = true;
else
Object = ObjRes;
MethodArgs[0] = Object.get();
// Check the argument types.
for (unsigned i = 0; i != NumParams; i++) {
Expr *Arg;
if (i < Args.size()) {
Arg = Args[i];
// Pass the argument.
ExprResult InputInit
= PerformCopyInitialization(InitializedEntity::InitializeParameter(
Context,
Method->getParamDecl(i)),
SourceLocation(), Arg);
IsError |= InputInit.isInvalid();
Arg = InputInit.getAs<Expr>();
} else {
ExprResult DefArg
= BuildCXXDefaultArgExpr(LParenLoc, Method, Method->getParamDecl(i));
if (DefArg.isInvalid()) {
IsError = true;
break;
}
Arg = DefArg.getAs<Expr>();
}
MethodArgs[i + 1] = Arg;
}
// If this is a variadic call, handle args passed through "...".
if (Proto->isVariadic()) {
// Promote the arguments (C99 6.5.2.2p7).
for (unsigned i = NumParams, e = Args.size(); i < e; i++) {
ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
nullptr);
IsError |= Arg.isInvalid();
MethodArgs[i + 1] = Arg.get();
}
}
if (IsError)
return true;
DiagnoseSentinelCalls(Method, LParenLoc, Args);
// Once we've built TheCall, all of the expressions are properly owned.
QualType ResultTy = Method->getReturnType();
ExprValueKind VK = Expr::getValueKindForType(ResultTy);
ResultTy = ResultTy.getNonLValueExprType(Context);
CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
Context, OO_Call, NewFn.get(), MethodArgs, ResultTy, VK, RParenLoc,
CurFPFeatureOverrides());
if (CheckCallReturnType(Method->getReturnType(), LParenLoc, TheCall, Method))
return true;
if (CheckFunctionCall(Method, TheCall, Proto))
return true;
return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall), Method);
}
/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator->
/// (if one exists), where @c Base is an expression of class type and
/// @c Member is the name of the member we're trying to find.
ExprResult
Sema::BuildOverloadedArrowExpr(Scope *S, Expr *Base, SourceLocation OpLoc,
bool *NoArrowOperatorFound) {
assert(Base->getType()->isRecordType() &&
"left-hand side must have class type");
if (checkPlaceholderForOverload(*this, Base))
return ExprError();
SourceLocation Loc = Base->getExprLoc();
// C++ [over.ref]p1:
//
// [...] An expression x->m is interpreted as (x.operator->())->m
// for a class object x of type T if T::operator->() exists and if
// the operator is selected as the best match function by the
// overload resolution mechanism (13.3).
DeclarationName OpName =
Context.DeclarationNames.getCXXOperatorName(OO_Arrow);
OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Operator);
if (RequireCompleteType(Loc, Base->getType(),
diag::err_typecheck_incomplete_tag, Base))
return ExprError();
LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName);
LookupQualifiedName(R, Base->getType()->castAs<RecordType>()->getDecl());
R.suppressDiagnostics();
for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end();
Oper != OperEnd; ++Oper) {
AddMethodCandidate(Oper.getPair(), Base->getType(), Base->Classify(Context),
None, CandidateSet, /*SuppressUserConversion=*/false);
}
bool HadMultipleCandidates = (CandidateSet.size() > 1);
// Perform overload resolution.
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
case OR_Success:
// Overload resolution succeeded; we'll build the call below.
break;
case OR_No_Viable_Function: {
auto Cands = CandidateSet.CompleteCandidates(*this, OCD_AllCandidates, Base);
if (CandidateSet.empty()) {
QualType BaseType = Base->getType();
if (NoArrowOperatorFound) {
// Report this specific error to the caller instead of emitting a
// diagnostic, as requested.
*NoArrowOperatorFound = true;
return ExprError();
}
Diag(OpLoc, diag::err_typecheck_member_reference_arrow)
<< BaseType << Base->getSourceRange();
if (BaseType->isRecordType() && !BaseType->isPointerType()) {
Diag(OpLoc, diag::note_typecheck_member_reference_suggestion)
<< FixItHint::CreateReplacement(OpLoc, ".");
}
} else
Diag(OpLoc, diag::err_ovl_no_viable_oper)
<< "operator->" << Base->getSourceRange();
CandidateSet.NoteCandidates(*this, Base, Cands);
return ExprError();
}
case OR_Ambiguous:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_ambiguous_oper_unary)
<< "->" << Base->getType()
<< Base->getSourceRange()),
*this, OCD_AmbiguousCandidates, Base);
return ExprError();
case OR_Deleted:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_deleted_oper)
<< "->" << Base->getSourceRange()),
*this, OCD_AllCandidates, Base);
return ExprError();
}
CheckMemberOperatorAccess(OpLoc, Base, nullptr, Best->FoundDecl);
// Convert the object parameter.
CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function);
ExprResult BaseResult =
PerformObjectArgumentInitialization(Base, /*Qualifier=*/nullptr,
Best->FoundDecl, Method);
if (BaseResult.isInvalid())
return ExprError();
Base = BaseResult.get();
// Build the operator call.
ExprResult FnExpr = CreateFunctionRefExpr(*this, Method, Best->FoundDecl,
Base, HadMultipleCandidates, OpLoc);
if (FnExpr.isInvalid())
return ExprError();
QualType ResultTy = Method->getReturnType();
ExprValueKind VK = Expr::getValueKindForType(ResultTy);
ResultTy = ResultTy.getNonLValueExprType(Context);
CXXOperatorCallExpr *TheCall =
CXXOperatorCallExpr::Create(Context, OO_Arrow, FnExpr.get(), Base,
ResultTy, VK, OpLoc, CurFPFeatureOverrides());
if (CheckCallReturnType(Method->getReturnType(), OpLoc, TheCall, Method))
return ExprError();
if (CheckFunctionCall(Method, TheCall,
Method->getType()->castAs<FunctionProtoType>()))
return ExprError();
return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall), Method);
}
/// BuildLiteralOperatorCall - Build a UserDefinedLiteral by creating a call to
/// a literal operator described by the provided lookup results.
ExprResult Sema::BuildLiteralOperatorCall(LookupResult &R,
DeclarationNameInfo &SuffixInfo,
ArrayRef<Expr*> Args,
SourceLocation LitEndLoc,
TemplateArgumentListInfo *TemplateArgs) {
SourceLocation UDSuffixLoc = SuffixInfo.getCXXLiteralOperatorNameLoc();
OverloadCandidateSet CandidateSet(UDSuffixLoc,
OverloadCandidateSet::CSK_Normal);
AddNonMemberOperatorCandidates(R.asUnresolvedSet(), Args, CandidateSet,
TemplateArgs);
bool HadMultipleCandidates = (CandidateSet.size() > 1);
// Perform overload resolution. This will usually be trivial, but might need
// to perform substitutions for a literal operator template.
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(*this, UDSuffixLoc, Best)) {
case OR_Success:
case OR_Deleted:
break;
case OR_No_Viable_Function:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(UDSuffixLoc,
PDiag(diag::err_ovl_no_viable_function_in_call)
<< R.getLookupName()),
*this, OCD_AllCandidates, Args);
return ExprError();
case OR_Ambiguous:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(R.getNameLoc(), PDiag(diag::err_ovl_ambiguous_call)
<< R.getLookupName()),
*this, OCD_AmbiguousCandidates, Args);
return ExprError();
}
FunctionDecl *FD = Best->Function;
ExprResult Fn = CreateFunctionRefExpr(*this, FD, Best->FoundDecl,
nullptr, HadMultipleCandidates,
SuffixInfo.getLoc(),
SuffixInfo.getInfo());
if (Fn.isInvalid())
return true;
// Check the argument types. This should almost always be a no-op, except
// that array-to-pointer decay is applied to string literals.
Expr *ConvArgs[2];
for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
ExprResult InputInit = PerformCopyInitialization(
InitializedEntity::InitializeParameter(Context, FD->getParamDecl(ArgIdx)),
SourceLocation(), Args[ArgIdx]);
if (InputInit.isInvalid())
return true;
ConvArgs[ArgIdx] = InputInit.get();
}
QualType ResultTy = FD->getReturnType();
ExprValueKind VK = Expr::getValueKindForType(ResultTy);
ResultTy = ResultTy.getNonLValueExprType(Context);
UserDefinedLiteral *UDL = UserDefinedLiteral::Create(
Context, Fn.get(), llvm::makeArrayRef(ConvArgs, Args.size()), ResultTy,
VK, LitEndLoc, UDSuffixLoc, CurFPFeatureOverrides());
if (CheckCallReturnType(FD->getReturnType(), UDSuffixLoc, UDL, FD))
return ExprError();
if (CheckFunctionCall(FD, UDL, nullptr))
return ExprError();
return CheckForImmediateInvocation(MaybeBindToTemporary(UDL), FD);
}
/// Build a call to 'begin' or 'end' for a C++11 for-range statement. If the
/// given LookupResult is non-empty, it is assumed to describe a member which
/// will be invoked. Otherwise, the function will be found via argument
/// dependent lookup.
/// CallExpr is set to a valid expression and FRS_Success returned on success,
/// otherwise CallExpr is set to ExprError() and some non-success value
/// is returned.
Sema::ForRangeStatus
Sema::BuildForRangeBeginEndCall(SourceLocation Loc,
SourceLocation RangeLoc,
const DeclarationNameInfo &NameInfo,
LookupResult &MemberLookup,
OverloadCandidateSet *CandidateSet,
Expr *Range, ExprResult *CallExpr) {
Scope *S = nullptr;
CandidateSet->clear(OverloadCandidateSet::CSK_Normal);
if (!MemberLookup.empty()) {
ExprResult MemberRef =
BuildMemberReferenceExpr(Range, Range->getType(), Loc,
/*IsPtr=*/false, CXXScopeSpec(),
/*TemplateKWLoc=*/SourceLocation(),
/*FirstQualifierInScope=*/nullptr,
MemberLookup,
/*TemplateArgs=*/nullptr, S);
if (MemberRef.isInvalid()) {
*CallExpr = ExprError();
return FRS_DiagnosticIssued;
}
*CallExpr = BuildCallExpr(S, MemberRef.get(), Loc, None, Loc, nullptr);
if (CallExpr->isInvalid()) {
*CallExpr = ExprError();
return FRS_DiagnosticIssued;
}
} else {
ExprResult FnR = CreateUnresolvedLookupExpr(/*NamingClass=*/nullptr,
NestedNameSpecifierLoc(),
NameInfo, UnresolvedSet<0>());
if (FnR.isInvalid())
return FRS_DiagnosticIssued;
UnresolvedLookupExpr *Fn = cast<UnresolvedLookupExpr>(FnR.get());
bool CandidateSetError = buildOverloadedCallSet(S, Fn, Fn, Range, Loc,
CandidateSet, CallExpr);
if (CandidateSet->empty() || CandidateSetError) {
*CallExpr = ExprError();
return FRS_NoViableFunction;
}
OverloadCandidateSet::iterator Best;
OverloadingResult OverloadResult =
CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best);
if (OverloadResult == OR_No_Viable_Function) {
*CallExpr = ExprError();
return FRS_NoViableFunction;
}
*CallExpr = FinishOverloadedCallExpr(*this, S, Fn, Fn, Loc, Range,
Loc, nullptr, CandidateSet, &Best,
OverloadResult,
/*AllowTypoCorrection=*/false);
if (CallExpr->isInvalid() || OverloadResult != OR_Success) {
*CallExpr = ExprError();
return FRS_DiagnosticIssued;
}
}
return FRS_Success;
}
/// FixOverloadedFunctionReference - E is an expression that refers to
/// a C++ overloaded function (possibly with some parentheses and
/// perhaps a '&' around it). We have resolved the overloaded function
/// to the function declaration Fn, so patch up the expression E to
/// refer (possibly indirectly) to Fn. Returns the new expr.
Expr *Sema::FixOverloadedFunctionReference(Expr *E, DeclAccessPair Found,
FunctionDecl *Fn) {
if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
Expr *SubExpr = FixOverloadedFunctionReference(PE->getSubExpr(),
Found, Fn);
if (SubExpr == PE->getSubExpr())
return PE;
return new (Context) ParenExpr(PE->getLParen(), PE->getRParen(), SubExpr);
}
if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
Expr *SubExpr = FixOverloadedFunctionReference(ICE->getSubExpr(),
Found, Fn);
assert(Context.hasSameType(ICE->getSubExpr()->getType(),
SubExpr->getType()) &&
"Implicit cast type cannot be determined from overload");
assert(ICE->path_empty() && "fixing up hierarchy conversion?");
if (SubExpr == ICE->getSubExpr())
return ICE;
return ImplicitCastExpr::Create(Context, ICE->getType(), ICE->getCastKind(),
SubExpr, nullptr, ICE->getValueKind(),
CurFPFeatureOverrides());
}
if (auto *GSE = dyn_cast<GenericSelectionExpr>(E)) {
if (!GSE->isResultDependent()) {
Expr *SubExpr =
FixOverloadedFunctionReference(GSE->getResultExpr(), Found, Fn);
if (SubExpr == GSE->getResultExpr())
return GSE;
// Replace the resulting type information before rebuilding the generic
// selection expression.
ArrayRef<Expr *> A = GSE->getAssocExprs();
SmallVector<Expr *, 4> AssocExprs(A.begin(), A.end());
unsigned ResultIdx = GSE->getResultIndex();
AssocExprs[ResultIdx] = SubExpr;
return GenericSelectionExpr::Create(
Context, GSE->getGenericLoc(), GSE->getControllingExpr(),
GSE->getAssocTypeSourceInfos(), AssocExprs, GSE->getDefaultLoc(),
GSE->getRParenLoc(), GSE->containsUnexpandedParameterPack(),
ResultIdx);
}
// Rather than fall through to the unreachable, return the original generic
// selection expression.
return GSE;
}
if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) {
assert(UnOp->getOpcode() == UO_AddrOf &&
"Can only take the address of an overloaded function");
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) {
if (Method->isStatic()) {
// Do nothing: static member functions aren't any different
// from non-member functions.
} else {
// Fix the subexpression, which really has to be an
// UnresolvedLookupExpr holding an overloaded member function
// or template.
Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(),
Found, Fn);
if (SubExpr == UnOp->getSubExpr())
return UnOp;
assert(isa<DeclRefExpr>(SubExpr)
&& "fixed to something other than a decl ref");
assert(cast<DeclRefExpr>(SubExpr)->getQualifier()
&& "fixed to a member ref with no nested name qualifier");
// We have taken the address of a pointer to member
// function. Perform the computation here so that we get the
// appropriate pointer to member type.
QualType ClassType
= Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext()));
QualType MemPtrType
= Context.getMemberPointerType(Fn->getType(), ClassType.getTypePtr());
// Under the MS ABI, lock down the inheritance model now.
if (Context.getTargetInfo().getCXXABI().isMicrosoft())
(void)isCompleteType(UnOp->getOperatorLoc(), MemPtrType);
return UnaryOperator::Create(
Context, SubExpr, UO_AddrOf, MemPtrType, VK_PRValue, OK_Ordinary,
UnOp->getOperatorLoc(), false, CurFPFeatureOverrides());
}
}
Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(),
Found, Fn);
if (SubExpr == UnOp->getSubExpr())
return UnOp;
return UnaryOperator::Create(
Context, SubExpr, UO_AddrOf, Context.getPointerType(SubExpr->getType()),
VK_PRValue, OK_Ordinary, UnOp->getOperatorLoc(), false,
CurFPFeatureOverrides());
}
if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) {
// FIXME: avoid copy.
TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
if (ULE->hasExplicitTemplateArgs()) {
ULE->copyTemplateArgumentsInto(TemplateArgsBuffer);
TemplateArgs = &TemplateArgsBuffer;
}
DeclRefExpr *DRE =
BuildDeclRefExpr(Fn, Fn->getType(), VK_LValue, ULE->getNameInfo(),
ULE->getQualifierLoc(), Found.getDecl(),
ULE->getTemplateKeywordLoc(), TemplateArgs);
DRE->setHadMultipleCandidates(ULE->getNumDecls() > 1);
return DRE;
}
if (UnresolvedMemberExpr *MemExpr = dyn_cast<UnresolvedMemberExpr>(E)) {
// FIXME: avoid copy.
TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
if (MemExpr->hasExplicitTemplateArgs()) {
MemExpr->copyTemplateArgumentsInto(TemplateArgsBuffer);
TemplateArgs = &TemplateArgsBuffer;
}
Expr *Base;
// If we're filling in a static method where we used to have an
// implicit member access, rewrite to a simple decl ref.
if (MemExpr->isImplicitAccess()) {
if (cast<CXXMethodDecl>(Fn)->isStatic()) {
DeclRefExpr *DRE = BuildDeclRefExpr(
Fn, Fn->getType(), VK_LValue, MemExpr->getNameInfo(),
MemExpr->getQualifierLoc(), Found.getDecl(),
MemExpr->getTemplateKeywordLoc(), TemplateArgs);
DRE->setHadMultipleCandidates(MemExpr->getNumDecls() > 1);
return DRE;
} else {
SourceLocation Loc = MemExpr->getMemberLoc();
if (MemExpr->getQualifier())
Loc = MemExpr->getQualifierLoc().getBeginLoc();
Base =
BuildCXXThisExpr(Loc, MemExpr->getBaseType(), /*IsImplicit=*/true);
}
} else
Base = MemExpr->getBase();
ExprValueKind valueKind;
QualType type;
if (cast<CXXMethodDecl>(Fn)->isStatic()) {
valueKind = VK_LValue;
type = Fn->getType();
} else {
valueKind = VK_PRValue;
type = Context.BoundMemberTy;
}
return BuildMemberExpr(
Base, MemExpr->isArrow(), MemExpr->getOperatorLoc(),
MemExpr->getQualifierLoc(), MemExpr->getTemplateKeywordLoc(), Fn, Found,
/*HadMultipleCandidates=*/true, MemExpr->getMemberNameInfo(),
type, valueKind, OK_Ordinary, TemplateArgs);
}
llvm_unreachable("Invalid reference to overloaded function");
}
ExprResult Sema::FixOverloadedFunctionReference(ExprResult E,
DeclAccessPair Found,
FunctionDecl *Fn) {
return FixOverloadedFunctionReference(E.get(), Found, Fn);
}
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