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llvm-project/clang/lib/CodeGen/CGCall.cpp

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//===--- CGCall.cpp - Encapsulate calling convention details ----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// These classes wrap the information about a call or function
// definition used to handle ABI compliancy.
//
//===----------------------------------------------------------------------===//
#include "CGCall.h"
#include "CGCXXABI.h"
#include "ABIInfo.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "TargetInfo.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "llvm/Attributes.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Target/TargetData.h"
#include "llvm/InlineAsm.h"
#include "llvm/Transforms/Utils/Local.h"
using namespace clang;
using namespace CodeGen;
/***/
static unsigned ClangCallConvToLLVMCallConv(CallingConv CC) {
switch (CC) {
default: return llvm::CallingConv::C;
case CC_X86StdCall: return llvm::CallingConv::X86_StdCall;
case CC_X86FastCall: return llvm::CallingConv::X86_FastCall;
case CC_X86ThisCall: return llvm::CallingConv::X86_ThisCall;
case CC_AAPCS: return llvm::CallingConv::ARM_AAPCS;
case CC_AAPCS_VFP: return llvm::CallingConv::ARM_AAPCS_VFP;
// TODO: add support for CC_X86Pascal to llvm
}
}
/// Derives the 'this' type for codegen purposes, i.e. ignoring method
/// qualification.
/// FIXME: address space qualification?
static CanQualType GetThisType(ASTContext &Context, const CXXRecordDecl *RD) {
QualType RecTy = Context.getTagDeclType(RD)->getCanonicalTypeInternal();
return Context.getPointerType(CanQualType::CreateUnsafe(RecTy));
}
/// Returns the canonical formal type of the given C++ method.
static CanQual<FunctionProtoType> GetFormalType(const CXXMethodDecl *MD) {
return MD->getType()->getCanonicalTypeUnqualified()
.getAs<FunctionProtoType>();
}
/// Returns the "extra-canonicalized" return type, which discards
/// qualifiers on the return type. Codegen doesn't care about them,
/// and it makes ABI code a little easier to be able to assume that
/// all parameter and return types are top-level unqualified.
static CanQualType GetReturnType(QualType RetTy) {
return RetTy->getCanonicalTypeUnqualified().getUnqualifiedType();
}
/// Arrange the argument and result information for a value of the given
/// unprototyped freestanding function type.
const CGFunctionInfo &
CodeGenTypes::arrangeFreeFunctionType(CanQual<FunctionNoProtoType> FTNP) {
// When translating an unprototyped function type, always use a
// variadic type.
return arrangeLLVMFunctionInfo(FTNP->getResultType().getUnqualifiedType(),
ArrayRef<CanQualType>(),
FTNP->getExtInfo(),
RequiredArgs(0));
}
/// Arrange the LLVM function layout for a value of the given function
/// type, on top of any implicit parameters already stored. Use the
/// given ExtInfo instead of the ExtInfo from the function type.
static const CGFunctionInfo &arrangeLLVMFunctionInfo(CodeGenTypes &CGT,
SmallVectorImpl<CanQualType> &prefix,
CanQual<FunctionProtoType> FTP,
FunctionType::ExtInfo extInfo) {
RequiredArgs required = RequiredArgs::forPrototypePlus(FTP, prefix.size());
// FIXME: Kill copy.
for (unsigned i = 0, e = FTP->getNumArgs(); i != e; ++i)
prefix.push_back(FTP->getArgType(i));
CanQualType resultType = FTP->getResultType().getUnqualifiedType();
return CGT.arrangeLLVMFunctionInfo(resultType, prefix, extInfo, required);
}
/// Arrange the argument and result information for a free function (i.e.
/// not a C++ or ObjC instance method) of the given type.
static const CGFunctionInfo &arrangeFreeFunctionType(CodeGenTypes &CGT,
SmallVectorImpl<CanQualType> &prefix,
CanQual<FunctionProtoType> FTP) {
return arrangeLLVMFunctionInfo(CGT, prefix, FTP, FTP->getExtInfo());
}
/// Given the formal ext-info of a C++ instance method, adjust it
/// according to the C++ ABI in effect.
static void adjustCXXMethodInfo(CodeGenTypes &CGT,
FunctionType::ExtInfo &extInfo) {
// FIXME: thiscall on Microsoft
}
/// Arrange the argument and result information for a free function (i.e.
/// not a C++ or ObjC instance method) of the given type.
static const CGFunctionInfo &arrangeCXXMethodType(CodeGenTypes &CGT,
SmallVectorImpl<CanQualType> &prefix,
CanQual<FunctionProtoType> FTP) {
FunctionType::ExtInfo extInfo = FTP->getExtInfo();
adjustCXXMethodInfo(CGT, extInfo);
return arrangeLLVMFunctionInfo(CGT, prefix, FTP, extInfo);
}
/// Arrange the argument and result information for a value of the
/// given freestanding function type.
const CGFunctionInfo &
CodeGenTypes::arrangeFreeFunctionType(CanQual<FunctionProtoType> FTP) {
SmallVector<CanQualType, 16> argTypes;
return ::arrangeFreeFunctionType(*this, argTypes, FTP);
}
static CallingConv getCallingConventionForDecl(const Decl *D) {
// Set the appropriate calling convention for the Function.
if (D->hasAttr<StdCallAttr>())
return CC_X86StdCall;
if (D->hasAttr<FastCallAttr>())
return CC_X86FastCall;
if (D->hasAttr<ThisCallAttr>())
return CC_X86ThisCall;
if (D->hasAttr<PascalAttr>())
return CC_X86Pascal;
if (PcsAttr *PCS = D->getAttr<PcsAttr>())
return (PCS->getPCS() == PcsAttr::AAPCS ? CC_AAPCS : CC_AAPCS_VFP);
return CC_C;
}
/// Arrange the argument and result information for a call to an
/// unknown C++ non-static member function of the given abstract type.
/// The member function must be an ordinary function, i.e. not a
/// constructor or destructor.
const CGFunctionInfo &
CodeGenTypes::arrangeCXXMethodType(const CXXRecordDecl *RD,
const FunctionProtoType *FTP) {
SmallVector<CanQualType, 16> argTypes;
// Add the 'this' pointer.
argTypes.push_back(GetThisType(Context, RD));
return ::arrangeCXXMethodType(*this, argTypes,
FTP->getCanonicalTypeUnqualified().getAs<FunctionProtoType>());
}
/// Arrange the argument and result information for a declaration or
/// definition of the given C++ non-static member function. The
/// member function must be an ordinary function, i.e. not a
/// constructor or destructor.
const CGFunctionInfo &
CodeGenTypes::arrangeCXXMethodDeclaration(const CXXMethodDecl *MD) {
assert(!isa<CXXConstructorDecl>(MD) && "wrong method for contructors!");
assert(!isa<CXXDestructorDecl>(MD) && "wrong method for destructors!");
CanQual<FunctionProtoType> prototype = GetFormalType(MD);
if (MD->isInstance()) {
// The abstract case is perfectly fine.
return arrangeCXXMethodType(MD->getParent(), prototype.getTypePtr());
}
return arrangeFreeFunctionType(prototype);
}
/// Arrange the argument and result information for a declaration
/// or definition to the given constructor variant.
const CGFunctionInfo &
CodeGenTypes::arrangeCXXConstructorDeclaration(const CXXConstructorDecl *D,
CXXCtorType ctorKind) {
SmallVector<CanQualType, 16> argTypes;
argTypes.push_back(GetThisType(Context, D->getParent()));
CanQualType resultType = Context.VoidTy;
TheCXXABI.BuildConstructorSignature(D, ctorKind, resultType, argTypes);
CanQual<FunctionProtoType> FTP = GetFormalType(D);
RequiredArgs required = RequiredArgs::forPrototypePlus(FTP, argTypes.size());
// Add the formal parameters.
for (unsigned i = 0, e = FTP->getNumArgs(); i != e; ++i)
argTypes.push_back(FTP->getArgType(i));
FunctionType::ExtInfo extInfo = FTP->getExtInfo();
adjustCXXMethodInfo(*this, extInfo);
return arrangeLLVMFunctionInfo(resultType, argTypes, extInfo, required);
}
/// Arrange the argument and result information for a declaration,
/// definition, or call to the given destructor variant. It so
/// happens that all three cases produce the same information.
const CGFunctionInfo &
CodeGenTypes::arrangeCXXDestructor(const CXXDestructorDecl *D,
CXXDtorType dtorKind) {
SmallVector<CanQualType, 2> argTypes;
argTypes.push_back(GetThisType(Context, D->getParent()));
CanQualType resultType = Context.VoidTy;
TheCXXABI.BuildDestructorSignature(D, dtorKind, resultType, argTypes);
CanQual<FunctionProtoType> FTP = GetFormalType(D);
assert(FTP->getNumArgs() == 0 && "dtor with formal parameters");
FunctionType::ExtInfo extInfo = FTP->getExtInfo();
adjustCXXMethodInfo(*this, extInfo);
return arrangeLLVMFunctionInfo(resultType, argTypes, extInfo,
RequiredArgs::All);
}
/// Arrange the argument and result information for the declaration or
/// definition of the given function.
const CGFunctionInfo &
CodeGenTypes::arrangeFunctionDeclaration(const FunctionDecl *FD) {
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
if (MD->isInstance())
return arrangeCXXMethodDeclaration(MD);
CanQualType FTy = FD->getType()->getCanonicalTypeUnqualified();
assert(isa<FunctionType>(FTy));
// When declaring a function without a prototype, always use a
// non-variadic type.
if (isa<FunctionNoProtoType>(FTy)) {
CanQual<FunctionNoProtoType> noProto = FTy.getAs<FunctionNoProtoType>();
return arrangeLLVMFunctionInfo(noProto->getResultType(),
ArrayRef<CanQualType>(),
noProto->getExtInfo(),
RequiredArgs::All);
}
assert(isa<FunctionProtoType>(FTy));
return arrangeFreeFunctionType(FTy.getAs<FunctionProtoType>());
}
/// Arrange the argument and result information for the declaration or
/// definition of an Objective-C method.
const CGFunctionInfo &
CodeGenTypes::arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD) {
// It happens that this is the same as a call with no optional
// arguments, except also using the formal 'self' type.
return arrangeObjCMessageSendSignature(MD, MD->getSelfDecl()->getType());
}
/// Arrange the argument and result information for the function type
/// through which to perform a send to the given Objective-C method,
/// using the given receiver type. The receiver type is not always
/// the 'self' type of the method or even an Objective-C pointer type.
/// This is *not* the right method for actually performing such a
/// message send, due to the possibility of optional arguments.
const CGFunctionInfo &
CodeGenTypes::arrangeObjCMessageSendSignature(const ObjCMethodDecl *MD,
QualType receiverType) {
SmallVector<CanQualType, 16> argTys;
argTys.push_back(Context.getCanonicalParamType(receiverType));
argTys.push_back(Context.getCanonicalParamType(Context.getObjCSelType()));
// FIXME: Kill copy?
for (ObjCMethodDecl::param_const_iterator i = MD->param_begin(),
e = MD->param_end(); i != e; ++i) {
argTys.push_back(Context.getCanonicalParamType((*i)->getType()));
}
FunctionType::ExtInfo einfo;
einfo = einfo.withCallingConv(getCallingConventionForDecl(MD));
if (getContext().getLangOpts().ObjCAutoRefCount &&
MD->hasAttr<NSReturnsRetainedAttr>())
einfo = einfo.withProducesResult(true);
RequiredArgs required =
(MD->isVariadic() ? RequiredArgs(argTys.size()) : RequiredArgs::All);
return arrangeLLVMFunctionInfo(GetReturnType(MD->getResultType()), argTys,
einfo, required);
}
const CGFunctionInfo &
CodeGenTypes::arrangeGlobalDeclaration(GlobalDecl GD) {
// FIXME: Do we need to handle ObjCMethodDecl?
const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD))
return arrangeCXXConstructorDeclaration(CD, GD.getCtorType());
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(FD))
return arrangeCXXDestructor(DD, GD.getDtorType());
return arrangeFunctionDeclaration(FD);
}
/// Figure out the rules for calling a function with the given formal
/// type using the given arguments. The arguments are necessary
/// because the function might be unprototyped, in which case it's
/// target-dependent in crazy ways.
const CGFunctionInfo &
CodeGenTypes::arrangeFreeFunctionCall(const CallArgList &args,
const FunctionType *fnType) {
RequiredArgs required = RequiredArgs::All;
if (const FunctionProtoType *proto = dyn_cast<FunctionProtoType>(fnType)) {
if (proto->isVariadic())
required = RequiredArgs(proto->getNumArgs());
} else if (CGM.getTargetCodeGenInfo()
.isNoProtoCallVariadic(args, cast<FunctionNoProtoType>(fnType))) {
required = RequiredArgs(0);
}
return arrangeFreeFunctionCall(fnType->getResultType(), args,
fnType->getExtInfo(), required);
}
const CGFunctionInfo &
CodeGenTypes::arrangeFreeFunctionCall(QualType resultType,
const CallArgList &args,
FunctionType::ExtInfo info,
RequiredArgs required) {
// FIXME: Kill copy.
SmallVector<CanQualType, 16> argTypes;
for (CallArgList::const_iterator i = args.begin(), e = args.end();
i != e; ++i)
argTypes.push_back(Context.getCanonicalParamType(i->Ty));
return arrangeLLVMFunctionInfo(GetReturnType(resultType), argTypes, info,
required);
}
/// Arrange a call to a C++ method, passing the given arguments.
const CGFunctionInfo &
CodeGenTypes::arrangeCXXMethodCall(const CallArgList &args,
const FunctionProtoType *FPT,
RequiredArgs required) {
// FIXME: Kill copy.
SmallVector<CanQualType, 16> argTypes;
for (CallArgList::const_iterator i = args.begin(), e = args.end();
i != e; ++i)
argTypes.push_back(Context.getCanonicalParamType(i->Ty));
FunctionType::ExtInfo info = FPT->getExtInfo();
adjustCXXMethodInfo(*this, info);
return arrangeLLVMFunctionInfo(GetReturnType(FPT->getResultType()),
argTypes, info, required);
}
const CGFunctionInfo &
CodeGenTypes::arrangeFunctionDeclaration(QualType resultType,
const FunctionArgList &args,
const FunctionType::ExtInfo &info,
bool isVariadic) {
// FIXME: Kill copy.
SmallVector<CanQualType, 16> argTypes;
for (FunctionArgList::const_iterator i = args.begin(), e = args.end();
i != e; ++i)
argTypes.push_back(Context.getCanonicalParamType((*i)->getType()));
RequiredArgs required =
(isVariadic ? RequiredArgs(args.size()) : RequiredArgs::All);
return arrangeLLVMFunctionInfo(GetReturnType(resultType), argTypes, info,
required);
}
const CGFunctionInfo &CodeGenTypes::arrangeNullaryFunction() {
return arrangeLLVMFunctionInfo(getContext().VoidTy, ArrayRef<CanQualType>(),
FunctionType::ExtInfo(), RequiredArgs::All);
}
/// Arrange the argument and result information for an abstract value
/// of a given function type. This is the method which all of the
/// above functions ultimately defer to.
const CGFunctionInfo &
CodeGenTypes::arrangeLLVMFunctionInfo(CanQualType resultType,
ArrayRef<CanQualType> argTypes,
FunctionType::ExtInfo info,
RequiredArgs required) {
#ifndef NDEBUG
for (ArrayRef<CanQualType>::const_iterator
I = argTypes.begin(), E = argTypes.end(); I != E; ++I)
assert(I->isCanonicalAsParam());
#endif
unsigned CC = ClangCallConvToLLVMCallConv(info.getCC());
// Lookup or create unique function info.
llvm::FoldingSetNodeID ID;
CGFunctionInfo::Profile(ID, info, required, resultType, argTypes);
void *insertPos = 0;
CGFunctionInfo *FI = FunctionInfos.FindNodeOrInsertPos(ID, insertPos);
if (FI)
return *FI;
// Construct the function info. We co-allocate the ArgInfos.
FI = CGFunctionInfo::create(CC, info, resultType, argTypes, required);
FunctionInfos.InsertNode(FI, insertPos);
bool inserted = FunctionsBeingProcessed.insert(FI); (void)inserted;
assert(inserted && "Recursively being processed?");
// Compute ABI information.
getABIInfo().computeInfo(*FI);
// Loop over all of the computed argument and return value info. If any of
// them are direct or extend without a specified coerce type, specify the
// default now.
ABIArgInfo &retInfo = FI->getReturnInfo();
if (retInfo.canHaveCoerceToType() && retInfo.getCoerceToType() == 0)
retInfo.setCoerceToType(ConvertType(FI->getReturnType()));
for (CGFunctionInfo::arg_iterator I = FI->arg_begin(), E = FI->arg_end();
I != E; ++I)
if (I->info.canHaveCoerceToType() && I->info.getCoerceToType() == 0)
I->info.setCoerceToType(ConvertType(I->type));
bool erased = FunctionsBeingProcessed.erase(FI); (void)erased;
assert(erased && "Not in set?");
return *FI;
}
CGFunctionInfo *CGFunctionInfo::create(unsigned llvmCC,
const FunctionType::ExtInfo &info,
CanQualType resultType,
ArrayRef<CanQualType> argTypes,
RequiredArgs required) {
void *buffer = operator new(sizeof(CGFunctionInfo) +
sizeof(ArgInfo) * (argTypes.size() + 1));
CGFunctionInfo *FI = new(buffer) CGFunctionInfo();
FI->CallingConvention = llvmCC;
FI->EffectiveCallingConvention = llvmCC;
FI->ASTCallingConvention = info.getCC();
FI->NoReturn = info.getNoReturn();
FI->ReturnsRetained = info.getProducesResult();
FI->Required = required;
FI->HasRegParm = info.getHasRegParm();
FI->RegParm = info.getRegParm();
FI->NumArgs = argTypes.size();
FI->getArgsBuffer()[0].type = resultType;
for (unsigned i = 0, e = argTypes.size(); i != e; ++i)
FI->getArgsBuffer()[i + 1].type = argTypes[i];
return FI;
}
/***/
void CodeGenTypes::GetExpandedTypes(QualType type,
SmallVectorImpl<llvm::Type*> &expandedTypes) {
if (const ConstantArrayType *AT = Context.getAsConstantArrayType(type)) {
uint64_t NumElts = AT->getSize().getZExtValue();
for (uint64_t Elt = 0; Elt < NumElts; ++Elt)
GetExpandedTypes(AT->getElementType(), expandedTypes);
} else if (const RecordType *RT = type->getAs<RecordType>()) {
const RecordDecl *RD = RT->getDecl();
assert(!RD->hasFlexibleArrayMember() &&
"Cannot expand structure with flexible array.");
if (RD->isUnion()) {
// Unions can be here only in degenerative cases - all the fields are same
// after flattening. Thus we have to use the "largest" field.
const FieldDecl *LargestFD = 0;
CharUnits UnionSize = CharUnits::Zero();
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i) {
const FieldDecl *FD = *i;
assert(!FD->isBitField() &&
"Cannot expand structure with bit-field members.");
CharUnits FieldSize = getContext().getTypeSizeInChars(FD->getType());
if (UnionSize < FieldSize) {
UnionSize = FieldSize;
LargestFD = FD;
}
}
if (LargestFD)
GetExpandedTypes(LargestFD->getType(), expandedTypes);
} else {
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i) {
assert(!i->isBitField() &&
"Cannot expand structure with bit-field members.");
GetExpandedTypes(i->getType(), expandedTypes);
}
}
} else if (const ComplexType *CT = type->getAs<ComplexType>()) {
llvm::Type *EltTy = ConvertType(CT->getElementType());
expandedTypes.push_back(EltTy);
expandedTypes.push_back(EltTy);
} else
expandedTypes.push_back(ConvertType(type));
}
llvm::Function::arg_iterator
CodeGenFunction::ExpandTypeFromArgs(QualType Ty, LValue LV,
llvm::Function::arg_iterator AI) {
assert(LV.isSimple() &&
"Unexpected non-simple lvalue during struct expansion.");
if (const ConstantArrayType *AT = getContext().getAsConstantArrayType(Ty)) {
unsigned NumElts = AT->getSize().getZExtValue();
QualType EltTy = AT->getElementType();
for (unsigned Elt = 0; Elt < NumElts; ++Elt) {
llvm::Value *EltAddr = Builder.CreateConstGEP2_32(LV.getAddress(), 0, Elt);
LValue LV = MakeAddrLValue(EltAddr, EltTy);
AI = ExpandTypeFromArgs(EltTy, LV, AI);
}
} else if (const RecordType *RT = Ty->getAs<RecordType>()) {
RecordDecl *RD = RT->getDecl();
if (RD->isUnion()) {
// Unions can be here only in degenerative cases - all the fields are same
// after flattening. Thus we have to use the "largest" field.
const FieldDecl *LargestFD = 0;
CharUnits UnionSize = CharUnits::Zero();
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i) {
const FieldDecl *FD = *i;
assert(!FD->isBitField() &&
"Cannot expand structure with bit-field members.");
CharUnits FieldSize = getContext().getTypeSizeInChars(FD->getType());
if (UnionSize < FieldSize) {
UnionSize = FieldSize;
LargestFD = FD;
}
}
if (LargestFD) {
// FIXME: What are the right qualifiers here?
LValue SubLV = EmitLValueForField(LV, LargestFD);
AI = ExpandTypeFromArgs(LargestFD->getType(), SubLV, AI);
}
} else {
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i) {
FieldDecl *FD = *i;
QualType FT = FD->getType();
// FIXME: What are the right qualifiers here?
LValue SubLV = EmitLValueForField(LV, FD);
AI = ExpandTypeFromArgs(FT, SubLV, AI);
}
}
} else if (const ComplexType *CT = Ty->getAs<ComplexType>()) {
QualType EltTy = CT->getElementType();
llvm::Value *RealAddr = Builder.CreateStructGEP(LV.getAddress(), 0, "real");
EmitStoreThroughLValue(RValue::get(AI++), MakeAddrLValue(RealAddr, EltTy));
llvm::Value *ImagAddr = Builder.CreateStructGEP(LV.getAddress(), 1, "imag");
EmitStoreThroughLValue(RValue::get(AI++), MakeAddrLValue(ImagAddr, EltTy));
} else {
EmitStoreThroughLValue(RValue::get(AI), LV);
++AI;
}
return AI;
}
/// EnterStructPointerForCoercedAccess - Given a struct pointer that we are
/// accessing some number of bytes out of it, try to gep into the struct to get
/// at its inner goodness. Dive as deep as possible without entering an element
/// with an in-memory size smaller than DstSize.
static llvm::Value *
EnterStructPointerForCoercedAccess(llvm::Value *SrcPtr,
llvm::StructType *SrcSTy,
uint64_t DstSize, CodeGenFunction &CGF) {
// We can't dive into a zero-element struct.
if (SrcSTy->getNumElements() == 0) return SrcPtr;
llvm::Type *FirstElt = SrcSTy->getElementType(0);
// If the first elt is at least as large as what we're looking for, or if the
// first element is the same size as the whole struct, we can enter it.
uint64_t FirstEltSize =
CGF.CGM.getTargetData().getTypeAllocSize(FirstElt);
if (FirstEltSize < DstSize &&
FirstEltSize < CGF.CGM.getTargetData().getTypeAllocSize(SrcSTy))
return SrcPtr;
// GEP into the first element.
SrcPtr = CGF.Builder.CreateConstGEP2_32(SrcPtr, 0, 0, "coerce.dive");
// If the first element is a struct, recurse.
llvm::Type *SrcTy =
cast<llvm::PointerType>(SrcPtr->getType())->getElementType();
if (llvm::StructType *SrcSTy = dyn_cast<llvm::StructType>(SrcTy))
return EnterStructPointerForCoercedAccess(SrcPtr, SrcSTy, DstSize, CGF);
return SrcPtr;
}
/// CoerceIntOrPtrToIntOrPtr - Convert a value Val to the specific Ty where both
/// are either integers or pointers. This does a truncation of the value if it
/// is too large or a zero extension if it is too small.
static llvm::Value *CoerceIntOrPtrToIntOrPtr(llvm::Value *Val,
llvm::Type *Ty,
CodeGenFunction &CGF) {
if (Val->getType() == Ty)
return Val;
if (isa<llvm::PointerType>(Val->getType())) {
// If this is Pointer->Pointer avoid conversion to and from int.
if (isa<llvm::PointerType>(Ty))
return CGF.Builder.CreateBitCast(Val, Ty, "coerce.val");
// Convert the pointer to an integer so we can play with its width.
Val = CGF.Builder.CreatePtrToInt(Val, CGF.IntPtrTy, "coerce.val.pi");
}
llvm::Type *DestIntTy = Ty;
if (isa<llvm::PointerType>(DestIntTy))
DestIntTy = CGF.IntPtrTy;
if (Val->getType() != DestIntTy)
Val = CGF.Builder.CreateIntCast(Val, DestIntTy, false, "coerce.val.ii");
if (isa<llvm::PointerType>(Ty))
Val = CGF.Builder.CreateIntToPtr(Val, Ty, "coerce.val.ip");
return Val;
}
/// CreateCoercedLoad - Create a load from \arg SrcPtr interpreted as
/// a pointer to an object of type \arg Ty.
///
/// This safely handles the case when the src type is smaller than the
/// destination type; in this situation the values of bits which not
/// present in the src are undefined.
static llvm::Value *CreateCoercedLoad(llvm::Value *SrcPtr,
llvm::Type *Ty,
CodeGenFunction &CGF) {
llvm::Type *SrcTy =
cast<llvm::PointerType>(SrcPtr->getType())->getElementType();
// If SrcTy and Ty are the same, just do a load.
if (SrcTy == Ty)
return CGF.Builder.CreateLoad(SrcPtr);
uint64_t DstSize = CGF.CGM.getTargetData().getTypeAllocSize(Ty);
if (llvm::StructType *SrcSTy = dyn_cast<llvm::StructType>(SrcTy)) {
SrcPtr = EnterStructPointerForCoercedAccess(SrcPtr, SrcSTy, DstSize, CGF);
SrcTy = cast<llvm::PointerType>(SrcPtr->getType())->getElementType();
}
uint64_t SrcSize = CGF.CGM.getTargetData().getTypeAllocSize(SrcTy);
// If the source and destination are integer or pointer types, just do an
// extension or truncation to the desired type.
if ((isa<llvm::IntegerType>(Ty) || isa<llvm::PointerType>(Ty)) &&
(isa<llvm::IntegerType>(SrcTy) || isa<llvm::PointerType>(SrcTy))) {
llvm::LoadInst *Load = CGF.Builder.CreateLoad(SrcPtr);
return CoerceIntOrPtrToIntOrPtr(Load, Ty, CGF);
}
// If load is legal, just bitcast the src pointer.
if (SrcSize >= DstSize) {
// Generally SrcSize is never greater than DstSize, since this means we are
// losing bits. However, this can happen in cases where the structure has
// additional padding, for example due to a user specified alignment.
//
// FIXME: Assert that we aren't truncating non-padding bits when have access
// to that information.
llvm::Value *Casted =
CGF.Builder.CreateBitCast(SrcPtr, llvm::PointerType::getUnqual(Ty));
llvm::LoadInst *Load = CGF.Builder.CreateLoad(Casted);
// FIXME: Use better alignment / avoid requiring aligned load.
Load->setAlignment(1);
return Load;
}
// Otherwise do coercion through memory. This is stupid, but
// simple.
llvm::Value *Tmp = CGF.CreateTempAlloca(Ty);
llvm::Value *Casted =
CGF.Builder.CreateBitCast(Tmp, llvm::PointerType::getUnqual(SrcTy));
llvm::StoreInst *Store =
CGF.Builder.CreateStore(CGF.Builder.CreateLoad(SrcPtr), Casted);
// FIXME: Use better alignment / avoid requiring aligned store.
Store->setAlignment(1);
return CGF.Builder.CreateLoad(Tmp);
}
// Function to store a first-class aggregate into memory. We prefer to
// store the elements rather than the aggregate to be more friendly to
// fast-isel.
// FIXME: Do we need to recurse here?
static void BuildAggStore(CodeGenFunction &CGF, llvm::Value *Val,
llvm::Value *DestPtr, bool DestIsVolatile,
bool LowAlignment) {
// Prefer scalar stores to first-class aggregate stores.
if (llvm::StructType *STy =
dyn_cast<llvm::StructType>(Val->getType())) {
for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
llvm::Value *EltPtr = CGF.Builder.CreateConstGEP2_32(DestPtr, 0, i);
llvm::Value *Elt = CGF.Builder.CreateExtractValue(Val, i);
llvm::StoreInst *SI = CGF.Builder.CreateStore(Elt, EltPtr,
DestIsVolatile);
if (LowAlignment)
SI->setAlignment(1);
}
} else {
llvm::StoreInst *SI = CGF.Builder.CreateStore(Val, DestPtr, DestIsVolatile);
if (LowAlignment)
SI->setAlignment(1);
}
}
/// CreateCoercedStore - Create a store to \arg DstPtr from \arg Src,
/// where the source and destination may have different types.
///
/// This safely handles the case when the src type is larger than the
/// destination type; the upper bits of the src will be lost.
static void CreateCoercedStore(llvm::Value *Src,
llvm::Value *DstPtr,
bool DstIsVolatile,
CodeGenFunction &CGF) {
llvm::Type *SrcTy = Src->getType();
llvm::Type *DstTy =
cast<llvm::PointerType>(DstPtr->getType())->getElementType();
if (SrcTy == DstTy) {
CGF.Builder.CreateStore(Src, DstPtr, DstIsVolatile);
return;
}
uint64_t SrcSize = CGF.CGM.getTargetData().getTypeAllocSize(SrcTy);
if (llvm::StructType *DstSTy = dyn_cast<llvm::StructType>(DstTy)) {
DstPtr = EnterStructPointerForCoercedAccess(DstPtr, DstSTy, SrcSize, CGF);
DstTy = cast<llvm::PointerType>(DstPtr->getType())->getElementType();
}
// If the source and destination are integer or pointer types, just do an
// extension or truncation to the desired type.
if ((isa<llvm::IntegerType>(SrcTy) || isa<llvm::PointerType>(SrcTy)) &&
(isa<llvm::IntegerType>(DstTy) || isa<llvm::PointerType>(DstTy))) {
Src = CoerceIntOrPtrToIntOrPtr(Src, DstTy, CGF);
CGF.Builder.CreateStore(Src, DstPtr, DstIsVolatile);
return;
}
uint64_t DstSize = CGF.CGM.getTargetData().getTypeAllocSize(DstTy);
// If store is legal, just bitcast the src pointer.
if (SrcSize <= DstSize) {
llvm::Value *Casted =
CGF.Builder.CreateBitCast(DstPtr, llvm::PointerType::getUnqual(SrcTy));
// FIXME: Use better alignment / avoid requiring aligned store.
BuildAggStore(CGF, Src, Casted, DstIsVolatile, true);
} else {
// Otherwise do coercion through memory. This is stupid, but
// simple.
// Generally SrcSize is never greater than DstSize, since this means we are
// losing bits. However, this can happen in cases where the structure has
// additional padding, for example due to a user specified alignment.
//
// FIXME: Assert that we aren't truncating non-padding bits when have access
// to that information.
llvm::Value *Tmp = CGF.CreateTempAlloca(SrcTy);
CGF.Builder.CreateStore(Src, Tmp);
llvm::Value *Casted =
CGF.Builder.CreateBitCast(Tmp, llvm::PointerType::getUnqual(DstTy));
llvm::LoadInst *Load = CGF.Builder.CreateLoad(Casted);
// FIXME: Use better alignment / avoid requiring aligned load.
Load->setAlignment(1);
CGF.Builder.CreateStore(Load, DstPtr, DstIsVolatile);
}
}
/***/
bool CodeGenModule::ReturnTypeUsesSRet(const CGFunctionInfo &FI) {
return FI.getReturnInfo().isIndirect();
}
bool CodeGenModule::ReturnTypeUsesFPRet(QualType ResultType) {
if (const BuiltinType *BT = ResultType->getAs<BuiltinType>()) {
switch (BT->getKind()) {
default:
return false;
case BuiltinType::Float:
return getContext().getTargetInfo().useObjCFPRetForRealType(TargetInfo::Float);
case BuiltinType::Double:
return getContext().getTargetInfo().useObjCFPRetForRealType(TargetInfo::Double);
case BuiltinType::LongDouble:
return getContext().getTargetInfo().useObjCFPRetForRealType(
TargetInfo::LongDouble);
}
}
return false;
}
bool CodeGenModule::ReturnTypeUsesFP2Ret(QualType ResultType) {
if (const ComplexType *CT = ResultType->getAs<ComplexType>()) {
if (const BuiltinType *BT = CT->getElementType()->getAs<BuiltinType>()) {
if (BT->getKind() == BuiltinType::LongDouble)
return getContext().getTargetInfo().useObjCFP2RetForComplexLongDouble();
}
}
return false;
}
llvm::FunctionType *CodeGenTypes::GetFunctionType(GlobalDecl GD) {
const CGFunctionInfo &FI = arrangeGlobalDeclaration(GD);
return GetFunctionType(FI);
}
llvm::FunctionType *
CodeGenTypes::GetFunctionType(const CGFunctionInfo &FI) {
bool Inserted = FunctionsBeingProcessed.insert(&FI); (void)Inserted;
assert(Inserted && "Recursively being processed?");
SmallVector<llvm::Type*, 8> argTypes;
llvm::Type *resultType = 0;
const ABIArgInfo &retAI = FI.getReturnInfo();
switch (retAI.getKind()) {
case ABIArgInfo::Expand:
llvm_unreachable("Invalid ABI kind for return argument");
case ABIArgInfo::Extend:
case ABIArgInfo::Direct:
resultType = retAI.getCoerceToType();
break;
case ABIArgInfo::Indirect: {
assert(!retAI.getIndirectAlign() && "Align unused on indirect return.");
resultType = llvm::Type::getVoidTy(getLLVMContext());
QualType ret = FI.getReturnType();
llvm::Type *ty = ConvertType(ret);
unsigned addressSpace = Context.getTargetAddressSpace(ret);
argTypes.push_back(llvm::PointerType::get(ty, addressSpace));
break;
}
case ABIArgInfo::Ignore:
resultType = llvm::Type::getVoidTy(getLLVMContext());
break;
}
for (CGFunctionInfo::const_arg_iterator it = FI.arg_begin(),
ie = FI.arg_end(); it != ie; ++it) {
const ABIArgInfo &argAI = it->info;
switch (argAI.getKind()) {
case ABIArgInfo::Ignore:
break;
case ABIArgInfo::Indirect: {
// indirect arguments are always on the stack, which is addr space #0.
llvm::Type *LTy = ConvertTypeForMem(it->type);
argTypes.push_back(LTy->getPointerTo());
break;
}
case ABIArgInfo::Extend:
case ABIArgInfo::Direct: {
// Insert a padding type to ensure proper alignment.
if (llvm::Type *PaddingType = argAI.getPaddingType())
argTypes.push_back(PaddingType);
// If the coerce-to type is a first class aggregate, flatten it. Either
// way is semantically identical, but fast-isel and the optimizer
// generally likes scalar values better than FCAs.
llvm::Type *argType = argAI.getCoerceToType();
if (llvm::StructType *st = dyn_cast<llvm::StructType>(argType)) {
for (unsigned i = 0, e = st->getNumElements(); i != e; ++i)
argTypes.push_back(st->getElementType(i));
} else {
argTypes.push_back(argType);
}
break;
}
case ABIArgInfo::Expand:
GetExpandedTypes(it->type, argTypes);
break;
}
}
bool Erased = FunctionsBeingProcessed.erase(&FI); (void)Erased;
assert(Erased && "Not in set?");
return llvm::FunctionType::get(resultType, argTypes, FI.isVariadic());
}
llvm::Type *CodeGenTypes::GetFunctionTypeForVTable(GlobalDecl GD) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
if (!isFuncTypeConvertible(FPT))
return llvm::StructType::get(getLLVMContext());
const CGFunctionInfo *Info;
if (isa<CXXDestructorDecl>(MD))
Info = &arrangeCXXDestructor(cast<CXXDestructorDecl>(MD), GD.getDtorType());
else
Info = &arrangeCXXMethodDeclaration(MD);
return GetFunctionType(*Info);
}
void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI,
const Decl *TargetDecl,
AttributeListType &PAL,
unsigned &CallingConv) {
llvm::Attributes FuncAttrs;
llvm::Attributes RetAttrs;
CallingConv = FI.getEffectiveCallingConvention();
if (FI.isNoReturn())
FuncAttrs |= llvm::Attribute::NoReturn;
// FIXME: handle sseregparm someday...
if (TargetDecl) {
if (TargetDecl->hasAttr<ReturnsTwiceAttr>())
FuncAttrs |= llvm::Attribute::ReturnsTwice;
if (TargetDecl->hasAttr<NoThrowAttr>())
FuncAttrs |= llvm::Attribute::NoUnwind;
else if (const FunctionDecl *Fn = dyn_cast<FunctionDecl>(TargetDecl)) {
const FunctionProtoType *FPT = Fn->getType()->getAs<FunctionProtoType>();
if (FPT && FPT->isNothrow(getContext()))
FuncAttrs |= llvm::Attribute::NoUnwind;
}
if (TargetDecl->hasAttr<NoReturnAttr>())
FuncAttrs |= llvm::Attribute::NoReturn;
if (TargetDecl->hasAttr<ReturnsTwiceAttr>())
FuncAttrs |= llvm::Attribute::ReturnsTwice;
// 'const' and 'pure' attribute functions are also nounwind.
if (TargetDecl->hasAttr<ConstAttr>()) {
FuncAttrs |= llvm::Attribute::ReadNone;
FuncAttrs |= llvm::Attribute::NoUnwind;
} else if (TargetDecl->hasAttr<PureAttr>()) {
FuncAttrs |= llvm::Attribute::ReadOnly;
FuncAttrs |= llvm::Attribute::NoUnwind;
}
if (TargetDecl->hasAttr<MallocAttr>())
RetAttrs |= llvm::Attribute::NoAlias;
}
if (CodeGenOpts.OptimizeSize)
FuncAttrs |= llvm::Attribute::OptimizeForSize;
if (CodeGenOpts.DisableRedZone)
FuncAttrs |= llvm::Attribute::NoRedZone;
if (CodeGenOpts.NoImplicitFloat)
FuncAttrs |= llvm::Attribute::NoImplicitFloat;
QualType RetTy = FI.getReturnType();
unsigned Index = 1;
const ABIArgInfo &RetAI = FI.getReturnInfo();
switch (RetAI.getKind()) {
case ABIArgInfo::Extend:
if (RetTy->hasSignedIntegerRepresentation())
RetAttrs |= llvm::Attribute::SExt;
else if (RetTy->hasUnsignedIntegerRepresentation())
RetAttrs |= llvm::Attribute::ZExt;
break;
case ABIArgInfo::Direct:
case ABIArgInfo::Ignore:
break;
case ABIArgInfo::Indirect:
PAL.push_back(llvm::AttributeWithIndex::get(Index,
llvm::Attribute::StructRet));
++Index;
// sret disables readnone and readonly
FuncAttrs &= ~(llvm::Attribute::ReadOnly |
llvm::Attribute::ReadNone);
break;
case ABIArgInfo::Expand:
llvm_unreachable("Invalid ABI kind for return argument");
}
if (RetAttrs)
PAL.push_back(llvm::AttributeWithIndex::get(0, RetAttrs));
// FIXME: RegParm should be reduced in case of global register variable.
signed RegParm;
if (FI.getHasRegParm())
RegParm = FI.getRegParm();
else
RegParm = CodeGenOpts.NumRegisterParameters;
unsigned PointerWidth = getContext().getTargetInfo().getPointerWidth(0);
for (CGFunctionInfo::const_arg_iterator it = FI.arg_begin(),
ie = FI.arg_end(); it != ie; ++it) {
QualType ParamType = it->type;
const ABIArgInfo &AI = it->info;
llvm::Attributes Attrs;
// 'restrict' -> 'noalias' is done in EmitFunctionProlog when we
// have the corresponding parameter variable. It doesn't make
// sense to do it here because parameters are so messed up.
switch (AI.getKind()) {
case ABIArgInfo::Extend:
if (ParamType->isSignedIntegerOrEnumerationType())
Attrs |= llvm::Attribute::SExt;
else if (ParamType->isUnsignedIntegerOrEnumerationType())
Attrs |= llvm::Attribute::ZExt;
// FALL THROUGH
case ABIArgInfo::Direct:
if (RegParm > 0 &&
(ParamType->isIntegerType() || ParamType->isPointerType() ||
ParamType->isReferenceType())) {
RegParm -=
(Context.getTypeSize(ParamType) + PointerWidth - 1) / PointerWidth;
if (RegParm >= 0)
Attrs |= llvm::Attribute::InReg;
}
// FIXME: handle sseregparm someday...
// Increment Index if there is padding.
Index += (AI.getPaddingType() != 0);
if (llvm::StructType *STy =
dyn_cast<llvm::StructType>(AI.getCoerceToType()))
Index += STy->getNumElements()-1; // 1 will be added below.
break;
case ABIArgInfo::Indirect:
if (AI.getIndirectByVal())
Attrs |= llvm::Attribute::ByVal;
Attrs |=
llvm::Attribute::constructAlignmentFromInt(AI.getIndirectAlign());
// byval disables readnone and readonly.
FuncAttrs &= ~(llvm::Attribute::ReadOnly |
llvm::Attribute::ReadNone);
break;
case ABIArgInfo::Ignore:
// Skip increment, no matching LLVM parameter.
continue;
case ABIArgInfo::Expand: {
SmallVector<llvm::Type*, 8> types;
// FIXME: This is rather inefficient. Do we ever actually need to do
// anything here? The result should be just reconstructed on the other
// side, so extension should be a non-issue.
getTypes().GetExpandedTypes(ParamType, types);
Index += types.size();
continue;
}
}
if (Attrs)
PAL.push_back(llvm::AttributeWithIndex::get(Index, Attrs));
++Index;
}
if (FuncAttrs)
PAL.push_back(llvm::AttributeWithIndex::get(~0, FuncAttrs));
}
/// An argument came in as a promoted argument; demote it back to its
/// declared type.
static llvm::Value *emitArgumentDemotion(CodeGenFunction &CGF,
const VarDecl *var,
llvm::Value *value) {
llvm::Type *varType = CGF.ConvertType(var->getType());
// This can happen with promotions that actually don't change the
// underlying type, like the enum promotions.
if (value->getType() == varType) return value;
assert((varType->isIntegerTy() || varType->isFloatingPointTy())
&& "unexpected promotion type");
if (isa<llvm::IntegerType>(varType))
return CGF.Builder.CreateTrunc(value, varType, "arg.unpromote");
return CGF.Builder.CreateFPCast(value, varType, "arg.unpromote");
}
void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI,
llvm::Function *Fn,
const FunctionArgList &Args) {
// If this is an implicit-return-zero function, go ahead and
// initialize the return value. TODO: it might be nice to have
// a more general mechanism for this that didn't require synthesized
// return statements.
if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(CurFuncDecl)) {
if (FD->hasImplicitReturnZero()) {
QualType RetTy = FD->getResultType().getUnqualifiedType();
llvm::Type* LLVMTy = CGM.getTypes().ConvertType(RetTy);
llvm::Constant* Zero = llvm::Constant::getNullValue(LLVMTy);
Builder.CreateStore(Zero, ReturnValue);
}
}
// FIXME: We no longer need the types from FunctionArgList; lift up and
// simplify.
// Emit allocs for param decls. Give the LLVM Argument nodes names.
llvm::Function::arg_iterator AI = Fn->arg_begin();
// Name the struct return argument.
if (CGM.ReturnTypeUsesSRet(FI)) {
AI->setName("agg.result");
AI->addAttr(llvm::Attribute::NoAlias);
++AI;
}
assert(FI.arg_size() == Args.size() &&
"Mismatch between function signature & arguments.");
unsigned ArgNo = 1;
CGFunctionInfo::const_arg_iterator info_it = FI.arg_begin();
for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
i != e; ++i, ++info_it, ++ArgNo) {
const VarDecl *Arg = *i;
QualType Ty = info_it->type;
const ABIArgInfo &ArgI = info_it->info;
bool isPromoted =
isa<ParmVarDecl>(Arg) && cast<ParmVarDecl>(Arg)->isKNRPromoted();
switch (ArgI.getKind()) {
case ABIArgInfo::Indirect: {
llvm::Value *V = AI;
if (hasAggregateLLVMType(Ty)) {
// Aggregates and complex variables are accessed by reference. All we
// need to do is realign the value, if requested
if (ArgI.getIndirectRealign()) {
llvm::Value *AlignedTemp = CreateMemTemp(Ty, "coerce");
// Copy from the incoming argument pointer to the temporary with the
// appropriate alignment.
//
// FIXME: We should have a common utility for generating an aggregate
// copy.
llvm::Type *I8PtrTy = Builder.getInt8PtrTy();
CharUnits Size = getContext().getTypeSizeInChars(Ty);
llvm::Value *Dst = Builder.CreateBitCast(AlignedTemp, I8PtrTy);
llvm::Value *Src = Builder.CreateBitCast(V, I8PtrTy);
Builder.CreateMemCpy(Dst,
Src,
llvm::ConstantInt::get(IntPtrTy,
Size.getQuantity()),
ArgI.getIndirectAlign(),
false);
V = AlignedTemp;
}
} else {
// Load scalar value from indirect argument.
CharUnits Alignment = getContext().getTypeAlignInChars(Ty);
V = EmitLoadOfScalar(V, false, Alignment.getQuantity(), Ty);
if (isPromoted)
V = emitArgumentDemotion(*this, Arg, V);
}
EmitParmDecl(*Arg, V, ArgNo);
break;
}
case ABIArgInfo::Extend:
case ABIArgInfo::Direct: {
// Skip the dummy padding argument.
if (ArgI.getPaddingType())
++AI;
// If we have the trivial case, handle it with no muss and fuss.
if (!isa<llvm::StructType>(ArgI.getCoerceToType()) &&
ArgI.getCoerceToType() == ConvertType(Ty) &&
ArgI.getDirectOffset() == 0) {
assert(AI != Fn->arg_end() && "Argument mismatch!");
llvm::Value *V = AI;
if (Arg->getType().isRestrictQualified())
AI->addAttr(llvm::Attribute::NoAlias);
// Ensure the argument is the correct type.
if (V->getType() != ArgI.getCoerceToType())
V = Builder.CreateBitCast(V, ArgI.getCoerceToType());
if (isPromoted)
V = emitArgumentDemotion(*this, Arg, V);
EmitParmDecl(*Arg, V, ArgNo);
break;
}
llvm::AllocaInst *Alloca = CreateMemTemp(Ty, Arg->getName());
// The alignment we need to use is the max of the requested alignment for
// the argument plus the alignment required by our access code below.
unsigned AlignmentToUse =
CGM.getTargetData().getABITypeAlignment(ArgI.getCoerceToType());
AlignmentToUse = std::max(AlignmentToUse,
(unsigned)getContext().getDeclAlign(Arg).getQuantity());
Alloca->setAlignment(AlignmentToUse);
llvm::Value *V = Alloca;
llvm::Value *Ptr = V; // Pointer to store into.
// If the value is offset in memory, apply the offset now.
if (unsigned Offs = ArgI.getDirectOffset()) {
Ptr = Builder.CreateBitCast(Ptr, Builder.getInt8PtrTy());
Ptr = Builder.CreateConstGEP1_32(Ptr, Offs);
Ptr = Builder.CreateBitCast(Ptr,
llvm::PointerType::getUnqual(ArgI.getCoerceToType()));
}
// If the coerce-to type is a first class aggregate, we flatten it and
// pass the elements. Either way is semantically identical, but fast-isel
// and the optimizer generally likes scalar values better than FCAs.
llvm::StructType *STy = dyn_cast<llvm::StructType>(ArgI.getCoerceToType());
if (STy && STy->getNumElements() > 1) {
uint64_t SrcSize = CGM.getTargetData().getTypeAllocSize(STy);
llvm::Type *DstTy =
cast<llvm::PointerType>(Ptr->getType())->getElementType();
uint64_t DstSize = CGM.getTargetData().getTypeAllocSize(DstTy);
if (SrcSize <= DstSize) {
Ptr = Builder.CreateBitCast(Ptr, llvm::PointerType::getUnqual(STy));
for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
assert(AI != Fn->arg_end() && "Argument mismatch!");
AI->setName(Arg->getName() + ".coerce" + Twine(i));
llvm::Value *EltPtr = Builder.CreateConstGEP2_32(Ptr, 0, i);
Builder.CreateStore(AI++, EltPtr);
}
} else {
llvm::AllocaInst *TempAlloca =
CreateTempAlloca(ArgI.getCoerceToType(), "coerce");
TempAlloca->setAlignment(AlignmentToUse);
llvm::Value *TempV = TempAlloca;
for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
assert(AI != Fn->arg_end() && "Argument mismatch!");
AI->setName(Arg->getName() + ".coerce" + Twine(i));
llvm::Value *EltPtr = Builder.CreateConstGEP2_32(TempV, 0, i);
Builder.CreateStore(AI++, EltPtr);
}
Builder.CreateMemCpy(Ptr, TempV, DstSize, AlignmentToUse);
}
} else {
// Simple case, just do a coerced store of the argument into the alloca.
assert(AI != Fn->arg_end() && "Argument mismatch!");
AI->setName(Arg->getName() + ".coerce");
CreateCoercedStore(AI++, Ptr, /*DestIsVolatile=*/false, *this);
}
// Match to what EmitParmDecl is expecting for this type.
if (!CodeGenFunction::hasAggregateLLVMType(Ty)) {
V = EmitLoadOfScalar(V, false, AlignmentToUse, Ty);
if (isPromoted)
V = emitArgumentDemotion(*this, Arg, V);
}
EmitParmDecl(*Arg, V, ArgNo);
continue; // Skip ++AI increment, already done.
}
case ABIArgInfo::Expand: {
// If this structure was expanded into multiple arguments then
// we need to create a temporary and reconstruct it from the
// arguments.
llvm::AllocaInst *Alloca = CreateMemTemp(Ty);
CharUnits Align = getContext().getDeclAlign(Arg);
Alloca->setAlignment(Align.getQuantity());
LValue LV = MakeAddrLValue(Alloca, Ty, Align);
llvm::Function::arg_iterator End = ExpandTypeFromArgs(Ty, LV, AI);
EmitParmDecl(*Arg, Alloca, ArgNo);
// Name the arguments used in expansion and increment AI.
unsigned Index = 0;
for (; AI != End; ++AI, ++Index)
AI->setName(Arg->getName() + "." + Twine(Index));
continue;
}
case ABIArgInfo::Ignore:
// Initialize the local variable appropriately.
if (hasAggregateLLVMType(Ty))
EmitParmDecl(*Arg, CreateMemTemp(Ty), ArgNo);
else
EmitParmDecl(*Arg, llvm::UndefValue::get(ConvertType(Arg->getType())),
ArgNo);
// Skip increment, no matching LLVM parameter.
continue;
}
++AI;
}
assert(AI == Fn->arg_end() && "Argument mismatch!");
}
static void eraseUnusedBitCasts(llvm::Instruction *insn) {
while (insn->use_empty()) {
llvm::BitCastInst *bitcast = dyn_cast<llvm::BitCastInst>(insn);
if (!bitcast) return;
// This is "safe" because we would have used a ConstantExpr otherwise.
insn = cast<llvm::Instruction>(bitcast->getOperand(0));
bitcast->eraseFromParent();
}
}
/// Try to emit a fused autorelease of a return result.
static llvm::Value *tryEmitFusedAutoreleaseOfResult(CodeGenFunction &CGF,
llvm::Value *result) {
// We must be immediately followed the cast.
llvm::BasicBlock *BB = CGF.Builder.GetInsertBlock();
if (BB->empty()) return 0;
if (&BB->back() != result) return 0;
llvm::Type *resultType = result->getType();
// result is in a BasicBlock and is therefore an Instruction.
llvm::Instruction *generator = cast<llvm::Instruction>(result);
SmallVector<llvm::Instruction*,4> insnsToKill;
// Look for:
// %generator = bitcast %type1* %generator2 to %type2*
while (llvm::BitCastInst *bitcast = dyn_cast<llvm::BitCastInst>(generator)) {
// We would have emitted this as a constant if the operand weren't
// an Instruction.
generator = cast<llvm::Instruction>(bitcast->getOperand(0));
// Require the generator to be immediately followed by the cast.
if (generator->getNextNode() != bitcast)
return 0;
insnsToKill.push_back(bitcast);
}
// Look for:
// %generator = call i8* @objc_retain(i8* %originalResult)
// or
// %generator = call i8* @objc_retainAutoreleasedReturnValue(i8* %originalResult)
llvm::CallInst *call = dyn_cast<llvm::CallInst>(generator);
if (!call) return 0;
bool doRetainAutorelease;
if (call->getCalledValue() == CGF.CGM.getARCEntrypoints().objc_retain) {
doRetainAutorelease = true;
} else if (call->getCalledValue() == CGF.CGM.getARCEntrypoints()
.objc_retainAutoreleasedReturnValue) {
doRetainAutorelease = false;
// Look for an inline asm immediately preceding the call and kill it, too.
llvm::Instruction *prev = call->getPrevNode();
if (llvm::CallInst *asmCall = dyn_cast_or_null<llvm::CallInst>(prev))
if (asmCall->getCalledValue()
== CGF.CGM.getARCEntrypoints().retainAutoreleasedReturnValueMarker)
insnsToKill.push_back(prev);
} else {
return 0;
}
result = call->getArgOperand(0);
insnsToKill.push_back(call);
// Keep killing bitcasts, for sanity. Note that we no longer care
// about precise ordering as long as there's exactly one use.
while (llvm::BitCastInst *bitcast = dyn_cast<llvm::BitCastInst>(result)) {
if (!bitcast->hasOneUse()) break;
insnsToKill.push_back(bitcast);
result = bitcast->getOperand(0);
}
// Delete all the unnecessary instructions, from latest to earliest.
for (SmallVectorImpl<llvm::Instruction*>::iterator
i = insnsToKill.begin(), e = insnsToKill.end(); i != e; ++i)
(*i)->eraseFromParent();
// Do the fused retain/autorelease if we were asked to.
if (doRetainAutorelease)
result = CGF.EmitARCRetainAutoreleaseReturnValue(result);
// Cast back to the result type.
return CGF.Builder.CreateBitCast(result, resultType);
}
/// If this is a +1 of the value of an immutable 'self', remove it.
static llvm::Value *tryRemoveRetainOfSelf(CodeGenFunction &CGF,
llvm::Value *result) {
// This is only applicable to a method with an immutable 'self'.
const ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(CGF.CurCodeDecl);
if (!method) return 0;
const VarDecl *self = method->getSelfDecl();
if (!self->getType().isConstQualified()) return 0;
// Look for a retain call.
llvm::CallInst *retainCall =
dyn_cast<llvm::CallInst>(result->stripPointerCasts());
if (!retainCall ||
retainCall->getCalledValue() != CGF.CGM.getARCEntrypoints().objc_retain)
return 0;
// Look for an ordinary load of 'self'.
llvm::Value *retainedValue = retainCall->getArgOperand(0);
llvm::LoadInst *load =
dyn_cast<llvm::LoadInst>(retainedValue->stripPointerCasts());
if (!load || load->isAtomic() || load->isVolatile() ||
load->getPointerOperand() != CGF.GetAddrOfLocalVar(self))
return 0;
// Okay! Burn it all down. This relies for correctness on the
// assumption that the retain is emitted as part of the return and
// that thereafter everything is used "linearly".
llvm::Type *resultType = result->getType();
eraseUnusedBitCasts(cast<llvm::Instruction>(result));
assert(retainCall->use_empty());
retainCall->eraseFromParent();
eraseUnusedBitCasts(cast<llvm::Instruction>(retainedValue));
return CGF.Builder.CreateBitCast(load, resultType);
}
/// Emit an ARC autorelease of the result of a function.
///
/// \return the value to actually return from the function
static llvm::Value *emitAutoreleaseOfResult(CodeGenFunction &CGF,
llvm::Value *result) {
// If we're returning 'self', kill the initial retain. This is a
// heuristic attempt to "encourage correctness" in the really unfortunate
// case where we have a return of self during a dealloc and we desperately
// need to avoid the possible autorelease.
if (llvm::Value *self = tryRemoveRetainOfSelf(CGF, result))
return self;
// At -O0, try to emit a fused retain/autorelease.
if (CGF.shouldUseFusedARCCalls())
if (llvm::Value *fused = tryEmitFusedAutoreleaseOfResult(CGF, result))
return fused;
return CGF.EmitARCAutoreleaseReturnValue(result);
}
/// Heuristically search for a dominating store to the return-value slot.
static llvm::StoreInst *findDominatingStoreToReturnValue(CodeGenFunction &CGF) {
// If there are multiple uses of the return-value slot, just check
// for something immediately preceding the IP. Sometimes this can
// happen with how we generate implicit-returns; it can also happen
// with noreturn cleanups.
if (!CGF.ReturnValue->hasOneUse()) {
llvm::BasicBlock *IP = CGF.Builder.GetInsertBlock();
if (IP->empty()) return 0;
llvm::StoreInst *store = dyn_cast<llvm::StoreInst>(&IP->back());
if (!store) return 0;
if (store->getPointerOperand() != CGF.ReturnValue) return 0;
assert(!store->isAtomic() && !store->isVolatile()); // see below
return store;
}
llvm::StoreInst *store =
dyn_cast<llvm::StoreInst>(CGF.ReturnValue->use_back());
if (!store) return 0;
// These aren't actually possible for non-coerced returns, and we
// only care about non-coerced returns on this code path.
assert(!store->isAtomic() && !store->isVolatile());
// Now do a first-and-dirty dominance check: just walk up the
// single-predecessors chain from the current insertion point.
llvm::BasicBlock *StoreBB = store->getParent();
llvm::BasicBlock *IP = CGF.Builder.GetInsertBlock();
while (IP != StoreBB) {
if (!(IP = IP->getSinglePredecessor()))
return 0;
}
// Okay, the store's basic block dominates the insertion point; we
// can do our thing.
return store;
}
void CodeGenFunction::EmitFunctionEpilog(const CGFunctionInfo &FI) {
// Functions with no result always return void.
if (ReturnValue == 0) {
Builder.CreateRetVoid();
return;
}
llvm::DebugLoc RetDbgLoc;
llvm::Value *RV = 0;
QualType RetTy = FI.getReturnType();
const ABIArgInfo &RetAI = FI.getReturnInfo();
switch (RetAI.getKind()) {
case ABIArgInfo::Indirect: {
unsigned Alignment = getContext().getTypeAlignInChars(RetTy).getQuantity();
if (RetTy->isAnyComplexType()) {
ComplexPairTy RT = LoadComplexFromAddr(ReturnValue, false);
StoreComplexToAddr(RT, CurFn->arg_begin(), false);
} else if (CodeGenFunction::hasAggregateLLVMType(RetTy)) {
// Do nothing; aggregrates get evaluated directly into the destination.
} else {
EmitStoreOfScalar(Builder.CreateLoad(ReturnValue), CurFn->arg_begin(),
false, Alignment, RetTy);
}
break;
}
case ABIArgInfo::Extend:
case ABIArgInfo::Direct:
if (RetAI.getCoerceToType() == ConvertType(RetTy) &&
RetAI.getDirectOffset() == 0) {
// The internal return value temp always will have pointer-to-return-type
// type, just do a load.
// If there is a dominating store to ReturnValue, we can elide
// the load, zap the store, and usually zap the alloca.
if (llvm::StoreInst *SI = findDominatingStoreToReturnValue(*this)) {
// Get the stored value and nuke the now-dead store.
RetDbgLoc = SI->getDebugLoc();
RV = SI->getValueOperand();
SI->eraseFromParent();
// If that was the only use of the return value, nuke it as well now.
if (ReturnValue->use_empty() && isa<llvm::AllocaInst>(ReturnValue)) {
cast<llvm::AllocaInst>(ReturnValue)->eraseFromParent();
ReturnValue = 0;
}
// Otherwise, we have to do a simple load.
} else {
RV = Builder.CreateLoad(ReturnValue);
}
} else {
llvm::Value *V = ReturnValue;
// If the value is offset in memory, apply the offset now.
if (unsigned Offs = RetAI.getDirectOffset()) {
V = Builder.CreateBitCast(V, Builder.getInt8PtrTy());
V = Builder.CreateConstGEP1_32(V, Offs);
V = Builder.CreateBitCast(V,
llvm::PointerType::getUnqual(RetAI.getCoerceToType()));
}
RV = CreateCoercedLoad(V, RetAI.getCoerceToType(), *this);
}
// In ARC, end functions that return a retainable type with a call
// to objc_autoreleaseReturnValue.
if (AutoreleaseResult) {
assert(getLangOpts().ObjCAutoRefCount &&
!FI.isReturnsRetained() &&
RetTy->isObjCRetainableType());
RV = emitAutoreleaseOfResult(*this, RV);
}
break;
case ABIArgInfo::Ignore:
break;
case ABIArgInfo::Expand:
llvm_unreachable("Invalid ABI kind for return argument");
}
llvm::Instruction *Ret = RV ? Builder.CreateRet(RV) : Builder.CreateRetVoid();
if (!RetDbgLoc.isUnknown())
Ret->setDebugLoc(RetDbgLoc);
}
void CodeGenFunction::EmitDelegateCallArg(CallArgList &args,
const VarDecl *param) {
// StartFunction converted the ABI-lowered parameter(s) into a
// local alloca. We need to turn that into an r-value suitable
// for EmitCall.
llvm::Value *local = GetAddrOfLocalVar(param);
QualType type = param->getType();
// For the most part, we just need to load the alloca, except:
// 1) aggregate r-values are actually pointers to temporaries, and
// 2) references to aggregates are pointers directly to the aggregate.
// I don't know why references to non-aggregates are different here.
if (const ReferenceType *ref = type->getAs<ReferenceType>()) {
if (hasAggregateLLVMType(ref->getPointeeType()))
return args.add(RValue::getAggregate(local), type);
// Locals which are references to scalars are represented
// with allocas holding the pointer.
return args.add(RValue::get(Builder.CreateLoad(local)), type);
}
if (type->isAnyComplexType()) {
ComplexPairTy complex = LoadComplexFromAddr(local, /*volatile*/ false);
return args.add(RValue::getComplex(complex), type);
}
if (hasAggregateLLVMType(type))
return args.add(RValue::getAggregate(local), type);
unsigned alignment = getContext().getDeclAlign(param).getQuantity();
llvm::Value *value = EmitLoadOfScalar(local, false, alignment, type);
return args.add(RValue::get(value), type);
}
static bool isProvablyNull(llvm::Value *addr) {
return isa<llvm::ConstantPointerNull>(addr);
}
static bool isProvablyNonNull(llvm::Value *addr) {
return isa<llvm::AllocaInst>(addr);
}
/// Emit the actual writing-back of a writeback.
static void emitWriteback(CodeGenFunction &CGF,
const CallArgList::Writeback &writeback) {
llvm::Value *srcAddr = writeback.Address;
assert(!isProvablyNull(srcAddr) &&
"shouldn't have writeback for provably null argument");
llvm::BasicBlock *contBB = 0;
// If the argument wasn't provably non-null, we need to null check
// before doing the store.
bool provablyNonNull = isProvablyNonNull(srcAddr);
if (!provablyNonNull) {
llvm::BasicBlock *writebackBB = CGF.createBasicBlock("icr.writeback");
contBB = CGF.createBasicBlock("icr.done");
llvm::Value *isNull = CGF.Builder.CreateIsNull(srcAddr, "icr.isnull");
CGF.Builder.CreateCondBr(isNull, contBB, writebackBB);
CGF.EmitBlock(writebackBB);
}
// Load the value to writeback.
llvm::Value *value = CGF.Builder.CreateLoad(writeback.Temporary);
// Cast it back, in case we're writing an id to a Foo* or something.
value = CGF.Builder.CreateBitCast(value,
cast<llvm::PointerType>(srcAddr->getType())->getElementType(),
"icr.writeback-cast");
// Perform the writeback.
QualType srcAddrType = writeback.AddressType;
CGF.EmitStoreThroughLValue(RValue::get(value),
CGF.MakeAddrLValue(srcAddr, srcAddrType));
// Jump to the continuation block.
if (!provablyNonNull)
CGF.EmitBlock(contBB);
}
static void emitWritebacks(CodeGenFunction &CGF,
const CallArgList &args) {
for (CallArgList::writeback_iterator
i = args.writeback_begin(), e = args.writeback_end(); i != e; ++i)
emitWriteback(CGF, *i);
}
/// Emit an argument that's being passed call-by-writeback. That is,
/// we are passing the address of
static void emitWritebackArg(CodeGenFunction &CGF, CallArgList &args,
const ObjCIndirectCopyRestoreExpr *CRE) {
llvm::Value *srcAddr = CGF.EmitScalarExpr(CRE->getSubExpr());
// The dest and src types don't necessarily match in LLVM terms
// because of the crazy ObjC compatibility rules.
llvm::PointerType *destType =
cast<llvm::PointerType>(CGF.ConvertType(CRE->getType()));
// If the address is a constant null, just pass the appropriate null.
if (isProvablyNull(srcAddr)) {
args.add(RValue::get(llvm::ConstantPointerNull::get(destType)),
CRE->getType());
return;
}
QualType srcAddrType =
CRE->getSubExpr()->getType()->castAs<PointerType>()->getPointeeType();
// Create the temporary.
llvm::Value *temp = CGF.CreateTempAlloca(destType->getElementType(),
"icr.temp");
// Zero-initialize it if we're not doing a copy-initialization.
bool shouldCopy = CRE->shouldCopy();
if (!shouldCopy) {
llvm::Value *null =
llvm::ConstantPointerNull::get(
cast<llvm::PointerType>(destType->getElementType()));
CGF.Builder.CreateStore(null, temp);
}
llvm::BasicBlock *contBB = 0;
// If the address is *not* known to be non-null, we need to switch.
llvm::Value *finalArgument;
bool provablyNonNull = isProvablyNonNull(srcAddr);
if (provablyNonNull) {
finalArgument = temp;
} else {
llvm::Value *isNull = CGF.Builder.CreateIsNull(srcAddr, "icr.isnull");
finalArgument = CGF.Builder.CreateSelect(isNull,
llvm::ConstantPointerNull::get(destType),
temp, "icr.argument");
// If we need to copy, then the load has to be conditional, which
// means we need control flow.
if (shouldCopy) {
contBB = CGF.createBasicBlock("icr.cont");
llvm::BasicBlock *copyBB = CGF.createBasicBlock("icr.copy");
CGF.Builder.CreateCondBr(isNull, contBB, copyBB);
CGF.EmitBlock(copyBB);
}
}
// Perform a copy if necessary.
if (shouldCopy) {
LValue srcLV = CGF.MakeAddrLValue(srcAddr, srcAddrType);
RValue srcRV = CGF.EmitLoadOfLValue(srcLV);
assert(srcRV.isScalar());
llvm::Value *src = srcRV.getScalarVal();
src = CGF.Builder.CreateBitCast(src, destType->getElementType(),
"icr.cast");
// Use an ordinary store, not a store-to-lvalue.
CGF.Builder.CreateStore(src, temp);
}
// Finish the control flow if we needed it.
if (shouldCopy && !provablyNonNull)
CGF.EmitBlock(contBB);
args.addWriteback(srcAddr, srcAddrType, temp);
args.add(RValue::get(finalArgument), CRE->getType());
}
void CodeGenFunction::EmitCallArg(CallArgList &args, const Expr *E,
QualType type) {
if (const ObjCIndirectCopyRestoreExpr *CRE
= dyn_cast<ObjCIndirectCopyRestoreExpr>(E)) {
assert(getContext().getLangOpts().ObjCAutoRefCount);
assert(getContext().hasSameType(E->getType(), type));
return emitWritebackArg(*this, args, CRE);
}
assert(type->isReferenceType() == E->isGLValue() &&
"reference binding to unmaterialized r-value!");
if (E->isGLValue()) {
assert(E->getObjectKind() == OK_Ordinary);
return args.add(EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0),
type);
}
if (hasAggregateLLVMType(type) && !E->getType()->isAnyComplexType() &&
isa<ImplicitCastExpr>(E) &&
cast<CastExpr>(E)->getCastKind() == CK_LValueToRValue) {
LValue L = EmitLValue(cast<CastExpr>(E)->getSubExpr());
assert(L.isSimple());
args.add(L.asAggregateRValue(), type, /*NeedsCopy*/true);
return;
}
args.add(EmitAnyExprToTemp(E), type);
}
// In ObjC ARC mode with no ObjC ARC exception safety, tell the ARC
// optimizer it can aggressively ignore unwind edges.
void
CodeGenFunction::AddObjCARCExceptionMetadata(llvm::Instruction *Inst) {
if (CGM.getCodeGenOpts().OptimizationLevel != 0 &&
!CGM.getCodeGenOpts().ObjCAutoRefCountExceptions)
Inst->setMetadata("clang.arc.no_objc_arc_exceptions",
CGM.getNoObjCARCExceptionsMetadata());
}
/// Emits a call or invoke instruction to the given function, depending
/// on the current state of the EH stack.
llvm::CallSite
CodeGenFunction::EmitCallOrInvoke(llvm::Value *Callee,
ArrayRef<llvm::Value *> Args,
const Twine &Name) {
llvm::BasicBlock *InvokeDest = getInvokeDest();
llvm::Instruction *Inst;
if (!InvokeDest)
Inst = Builder.CreateCall(Callee, Args, Name);
else {
llvm::BasicBlock *ContBB = createBasicBlock("invoke.cont");
Inst = Builder.CreateInvoke(Callee, ContBB, InvokeDest, Args, Name);
EmitBlock(ContBB);
}
// In ObjC ARC mode with no ObjC ARC exception safety, tell the ARC
// optimizer it can aggressively ignore unwind edges.
if (CGM.getLangOpts().ObjCAutoRefCount)
AddObjCARCExceptionMetadata(Inst);
return Inst;
}
llvm::CallSite
CodeGenFunction::EmitCallOrInvoke(llvm::Value *Callee,
const Twine &Name) {
return EmitCallOrInvoke(Callee, ArrayRef<llvm::Value *>(), Name);
}
static void checkArgMatches(llvm::Value *Elt, unsigned &ArgNo,
llvm::FunctionType *FTy) {
if (ArgNo < FTy->getNumParams())
assert(Elt->getType() == FTy->getParamType(ArgNo));
else
assert(FTy->isVarArg());
++ArgNo;
}
void CodeGenFunction::ExpandTypeToArgs(QualType Ty, RValue RV,
SmallVector<llvm::Value*,16> &Args,
llvm::FunctionType *IRFuncTy) {
if (const ConstantArrayType *AT = getContext().getAsConstantArrayType(Ty)) {
unsigned NumElts = AT->getSize().getZExtValue();
QualType EltTy = AT->getElementType();
llvm::Value *Addr = RV.getAggregateAddr();
for (unsigned Elt = 0; Elt < NumElts; ++Elt) {
llvm::Value *EltAddr = Builder.CreateConstGEP2_32(Addr, 0, Elt);
LValue LV = MakeAddrLValue(EltAddr, EltTy);
RValue EltRV;
if (EltTy->isAnyComplexType())
// FIXME: Volatile?
EltRV = RValue::getComplex(LoadComplexFromAddr(LV.getAddress(), false));
else if (CodeGenFunction::hasAggregateLLVMType(EltTy))
EltRV = LV.asAggregateRValue();
else
EltRV = EmitLoadOfLValue(LV);
ExpandTypeToArgs(EltTy, EltRV, Args, IRFuncTy);
}
} else if (const RecordType *RT = Ty->getAs<RecordType>()) {
RecordDecl *RD = RT->getDecl();
assert(RV.isAggregate() && "Unexpected rvalue during struct expansion");
LValue LV = MakeAddrLValue(RV.getAggregateAddr(), Ty);
if (RD->isUnion()) {
const FieldDecl *LargestFD = 0;
CharUnits UnionSize = CharUnits::Zero();
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i) {
const FieldDecl *FD = *i;
assert(!FD->isBitField() &&
"Cannot expand structure with bit-field members.");
CharUnits FieldSize = getContext().getTypeSizeInChars(FD->getType());
if (UnionSize < FieldSize) {
UnionSize = FieldSize;
LargestFD = FD;
}
}
if (LargestFD) {
RValue FldRV = EmitRValueForField(LV, LargestFD);
ExpandTypeToArgs(LargestFD->getType(), FldRV, Args, IRFuncTy);
}
} else {
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i) {
FieldDecl *FD = *i;
RValue FldRV = EmitRValueForField(LV, FD);
ExpandTypeToArgs(FD->getType(), FldRV, Args, IRFuncTy);
}
}
} else if (Ty->isAnyComplexType()) {
ComplexPairTy CV = RV.getComplexVal();
Args.push_back(CV.first);
Args.push_back(CV.second);
} else {
assert(RV.isScalar() &&
"Unexpected non-scalar rvalue during struct expansion.");
// Insert a bitcast as needed.
llvm::Value *V = RV.getScalarVal();
if (Args.size() < IRFuncTy->getNumParams() &&
V->getType() != IRFuncTy->getParamType(Args.size()))
V = Builder.CreateBitCast(V, IRFuncTy->getParamType(Args.size()));
Args.push_back(V);
}
}
RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
llvm::Value *Callee,
ReturnValueSlot ReturnValue,
const CallArgList &CallArgs,
const Decl *TargetDecl,
llvm::Instruction **callOrInvoke) {
// FIXME: We no longer need the types from CallArgs; lift up and simplify.
SmallVector<llvm::Value*, 16> Args;
// Handle struct-return functions by passing a pointer to the
// location that we would like to return into.
QualType RetTy = CallInfo.getReturnType();
const ABIArgInfo &RetAI = CallInfo.getReturnInfo();
// IRArgNo - Keep track of the argument number in the callee we're looking at.
unsigned IRArgNo = 0;
llvm::FunctionType *IRFuncTy =
cast<llvm::FunctionType>(
cast<llvm::PointerType>(Callee->getType())->getElementType());
// If the call returns a temporary with struct return, create a temporary
// alloca to hold the result, unless one is given to us.
if (CGM.ReturnTypeUsesSRet(CallInfo)) {
llvm::Value *Value = ReturnValue.getValue();
if (!Value)
Value = CreateMemTemp(RetTy);
Args.push_back(Value);
checkArgMatches(Value, IRArgNo, IRFuncTy);
}
assert(CallInfo.arg_size() == CallArgs.size() &&
"Mismatch between function signature & arguments.");
CGFunctionInfo::const_arg_iterator info_it = CallInfo.arg_begin();
for (CallArgList::const_iterator I = CallArgs.begin(), E = CallArgs.end();
I != E; ++I, ++info_it) {
const ABIArgInfo &ArgInfo = info_it->info;
RValue RV = I->RV;
unsigned TypeAlign =
getContext().getTypeAlignInChars(I->Ty).getQuantity();
switch (ArgInfo.getKind()) {
case ABIArgInfo::Indirect: {
if (RV.isScalar() || RV.isComplex()) {
// Make a temporary alloca to pass the argument.
llvm::AllocaInst *AI = CreateMemTemp(I->Ty);
if (ArgInfo.getIndirectAlign() > AI->getAlignment())
AI->setAlignment(ArgInfo.getIndirectAlign());
Args.push_back(AI);
if (RV.isScalar())
EmitStoreOfScalar(RV.getScalarVal(), Args.back(), false,
TypeAlign, I->Ty);
else
StoreComplexToAddr(RV.getComplexVal(), Args.back(), false);
// Validate argument match.
checkArgMatches(AI, IRArgNo, IRFuncTy);
} else {
// We want to avoid creating an unnecessary temporary+copy here;
// however, we need one in two cases:
// 1. If the argument is not byval, and we are required to copy the
// source. (This case doesn't occur on any common architecture.)
// 2. If the argument is byval, RV is not sufficiently aligned, and
// we cannot force it to be sufficiently aligned.
llvm::Value *Addr = RV.getAggregateAddr();
unsigned Align = ArgInfo.getIndirectAlign();
const llvm::TargetData *TD = &CGM.getTargetData();
if ((!ArgInfo.getIndirectByVal() && I->NeedsCopy) ||
(ArgInfo.getIndirectByVal() && TypeAlign < Align &&
llvm::getOrEnforceKnownAlignment(Addr, Align, TD) < Align)) {
// Create an aligned temporary, and copy to it.
llvm::AllocaInst *AI = CreateMemTemp(I->Ty);
if (Align > AI->getAlignment())
AI->setAlignment(Align);
Args.push_back(AI);
EmitAggregateCopy(AI, Addr, I->Ty, RV.isVolatileQualified());
// Validate argument match.
checkArgMatches(AI, IRArgNo, IRFuncTy);
} else {
// Skip the extra memcpy call.
Args.push_back(Addr);
// Validate argument match.
checkArgMatches(Addr, IRArgNo, IRFuncTy);
}
}
break;
}
case ABIArgInfo::Ignore:
break;
case ABIArgInfo::Extend:
case ABIArgInfo::Direct: {
// Insert a padding argument to ensure proper alignment.
if (llvm::Type *PaddingType = ArgInfo.getPaddingType()) {
Args.push_back(llvm::UndefValue::get(PaddingType));
++IRArgNo;
}
if (!isa<llvm::StructType>(ArgInfo.getCoerceToType()) &&
ArgInfo.getCoerceToType() == ConvertType(info_it->type) &&
ArgInfo.getDirectOffset() == 0) {
llvm::Value *V;
if (RV.isScalar())
V = RV.getScalarVal();
else
V = Builder.CreateLoad(RV.getAggregateAddr());
// If the argument doesn't match, perform a bitcast to coerce it. This
// can happen due to trivial type mismatches.
if (IRArgNo < IRFuncTy->getNumParams() &&
V->getType() != IRFuncTy->getParamType(IRArgNo))
V = Builder.CreateBitCast(V, IRFuncTy->getParamType(IRArgNo));
Args.push_back(V);
checkArgMatches(V, IRArgNo, IRFuncTy);
break;
}
// FIXME: Avoid the conversion through memory if possible.
llvm::Value *SrcPtr;
if (RV.isScalar()) {
SrcPtr = CreateMemTemp(I->Ty, "coerce");
EmitStoreOfScalar(RV.getScalarVal(), SrcPtr, false, TypeAlign, I->Ty);
} else if (RV.isComplex()) {
SrcPtr = CreateMemTemp(I->Ty, "coerce");
StoreComplexToAddr(RV.getComplexVal(), SrcPtr, false);
} else
SrcPtr = RV.getAggregateAddr();
// If the value is offset in memory, apply the offset now.
if (unsigned Offs = ArgInfo.getDirectOffset()) {
SrcPtr = Builder.CreateBitCast(SrcPtr, Builder.getInt8PtrTy());
SrcPtr = Builder.CreateConstGEP1_32(SrcPtr, Offs);
SrcPtr = Builder.CreateBitCast(SrcPtr,
llvm::PointerType::getUnqual(ArgInfo.getCoerceToType()));
}
// If the coerce-to type is a first class aggregate, we flatten it and
// pass the elements. Either way is semantically identical, but fast-isel
// and the optimizer generally likes scalar values better than FCAs.
if (llvm::StructType *STy =
dyn_cast<llvm::StructType>(ArgInfo.getCoerceToType())) {
SrcPtr = Builder.CreateBitCast(SrcPtr,
llvm::PointerType::getUnqual(STy));
for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
llvm::Value *EltPtr = Builder.CreateConstGEP2_32(SrcPtr, 0, i);
llvm::LoadInst *LI = Builder.CreateLoad(EltPtr);
// We don't know what we're loading from.
LI->setAlignment(1);
Args.push_back(LI);
// Validate argument match.
checkArgMatches(LI, IRArgNo, IRFuncTy);
}
} else {
// In the simple case, just pass the coerced loaded value.
Args.push_back(CreateCoercedLoad(SrcPtr, ArgInfo.getCoerceToType(),
*this));
// Validate argument match.
checkArgMatches(Args.back(), IRArgNo, IRFuncTy);
}
break;
}
case ABIArgInfo::Expand:
ExpandTypeToArgs(I->Ty, RV, Args, IRFuncTy);
IRArgNo = Args.size();
break;
}
}
// If the callee is a bitcast of a function to a varargs pointer to function
// type, check to see if we can remove the bitcast. This handles some cases
// with unprototyped functions.
if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Callee))
if (llvm::Function *CalleeF = dyn_cast<llvm::Function>(CE->getOperand(0))) {
llvm::PointerType *CurPT=cast<llvm::PointerType>(Callee->getType());
llvm::FunctionType *CurFT =
cast<llvm::FunctionType>(CurPT->getElementType());
llvm::FunctionType *ActualFT = CalleeF->getFunctionType();
if (CE->getOpcode() == llvm::Instruction::BitCast &&
ActualFT->getReturnType() == CurFT->getReturnType() &&
ActualFT->getNumParams() == CurFT->getNumParams() &&
ActualFT->getNumParams() == Args.size() &&
(CurFT->isVarArg() || !ActualFT->isVarArg())) {
bool ArgsMatch = true;
for (unsigned i = 0, e = ActualFT->getNumParams(); i != e; ++i)
if (ActualFT->getParamType(i) != CurFT->getParamType(i)) {
ArgsMatch = false;
break;
}
// Strip the cast if we can get away with it. This is a nice cleanup,
// but also allows us to inline the function at -O0 if it is marked
// always_inline.
if (ArgsMatch)
Callee = CalleeF;
}
}
unsigned CallingConv;
CodeGen::AttributeListType AttributeList;
CGM.ConstructAttributeList(CallInfo, TargetDecl, AttributeList, CallingConv);
llvm::AttrListPtr Attrs = llvm::AttrListPtr::get(AttributeList);
llvm::BasicBlock *InvokeDest = 0;
if (!(Attrs.getFnAttributes() & llvm::Attribute::NoUnwind))
InvokeDest = getInvokeDest();
llvm::CallSite CS;
if (!InvokeDest) {
CS = Builder.CreateCall(Callee, Args);
} else {
llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
CS = Builder.CreateInvoke(Callee, Cont, InvokeDest, Args);
EmitBlock(Cont);
}
if (callOrInvoke)
*callOrInvoke = CS.getInstruction();
CS.setAttributes(Attrs);
CS.setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
// In ObjC ARC mode with no ObjC ARC exception safety, tell the ARC
// optimizer it can aggressively ignore unwind edges.
if (CGM.getLangOpts().ObjCAutoRefCount)
AddObjCARCExceptionMetadata(CS.getInstruction());
// If the call doesn't return, finish the basic block and clear the
// insertion point; this allows the rest of IRgen to discard
// unreachable code.
if (CS.doesNotReturn()) {
Builder.CreateUnreachable();
Builder.ClearInsertionPoint();
// FIXME: For now, emit a dummy basic block because expr emitters in
// generally are not ready to handle emitting expressions at unreachable
// points.
EnsureInsertPoint();
// Return a reasonable RValue.
return GetUndefRValue(RetTy);
}
llvm::Instruction *CI = CS.getInstruction();
if (Builder.isNamePreserving() && !CI->getType()->isVoidTy())
CI->setName("call");
// Emit any writebacks immediately. Arguably this should happen
// after any return-value munging.
if (CallArgs.hasWritebacks())
emitWritebacks(*this, CallArgs);
switch (RetAI.getKind()) {
case ABIArgInfo::Indirect: {
unsigned Alignment = getContext().getTypeAlignInChars(RetTy).getQuantity();
if (RetTy->isAnyComplexType())
return RValue::getComplex(LoadComplexFromAddr(Args[0], false));
if (CodeGenFunction::hasAggregateLLVMType(RetTy))
return RValue::getAggregate(Args[0]);
return RValue::get(EmitLoadOfScalar(Args[0], false, Alignment, RetTy));
}
case ABIArgInfo::Ignore:
// If we are ignoring an argument that had a result, make sure to
// construct the appropriate return value for our caller.
return GetUndefRValue(RetTy);
case ABIArgInfo::Extend:
case ABIArgInfo::Direct: {
llvm::Type *RetIRTy = ConvertType(RetTy);
if (RetAI.getCoerceToType() == RetIRTy && RetAI.getDirectOffset() == 0) {
if (RetTy->isAnyComplexType()) {
llvm::Value *Real = Builder.CreateExtractValue(CI, 0);
llvm::Value *Imag = Builder.CreateExtractValue(CI, 1);
return RValue::getComplex(std::make_pair(Real, Imag));
}
if (CodeGenFunction::hasAggregateLLVMType(RetTy)) {
llvm::Value *DestPtr = ReturnValue.getValue();
bool DestIsVolatile = ReturnValue.isVolatile();
if (!DestPtr) {
DestPtr = CreateMemTemp(RetTy, "agg.tmp");
DestIsVolatile = false;
}
BuildAggStore(*this, CI, DestPtr, DestIsVolatile, false);
return RValue::getAggregate(DestPtr);
}
// If the argument doesn't match, perform a bitcast to coerce it. This
// can happen due to trivial type mismatches.
llvm::Value *V = CI;
if (V->getType() != RetIRTy)
V = Builder.CreateBitCast(V, RetIRTy);
return RValue::get(V);
}
llvm::Value *DestPtr = ReturnValue.getValue();
bool DestIsVolatile = ReturnValue.isVolatile();
if (!DestPtr) {
DestPtr = CreateMemTemp(RetTy, "coerce");
DestIsVolatile = false;
}
// If the value is offset in memory, apply the offset now.
llvm::Value *StorePtr = DestPtr;
if (unsigned Offs = RetAI.getDirectOffset()) {
StorePtr = Builder.CreateBitCast(StorePtr, Builder.getInt8PtrTy());
StorePtr = Builder.CreateConstGEP1_32(StorePtr, Offs);
StorePtr = Builder.CreateBitCast(StorePtr,
llvm::PointerType::getUnqual(RetAI.getCoerceToType()));
}
CreateCoercedStore(CI, StorePtr, DestIsVolatile, *this);
unsigned Alignment = getContext().getTypeAlignInChars(RetTy).getQuantity();
if (RetTy->isAnyComplexType())
return RValue::getComplex(LoadComplexFromAddr(DestPtr, false));
if (CodeGenFunction::hasAggregateLLVMType(RetTy))
return RValue::getAggregate(DestPtr);
return RValue::get(EmitLoadOfScalar(DestPtr, false, Alignment, RetTy));
}
case ABIArgInfo::Expand:
llvm_unreachable("Invalid ABI kind for return argument");
}
llvm_unreachable("Unhandled ABIArgInfo::Kind");
}
/* VarArg handling */
llvm::Value *CodeGenFunction::EmitVAArg(llvm::Value *VAListAddr, QualType Ty) {
return CGM.getTypes().getABIInfo().EmitVAArg(VAListAddr, Ty, *this);
}
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