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

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//===--- CGVtable.cpp - Emit LLVM Code for C++ vtables --------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code dealing with C++ code generation of virtual tables.
//
//===----------------------------------------------------------------------===//
#include "CodeGenModule.h"
#include "CodeGenFunction.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/RecordLayout.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Format.h"
#include <cstdio>
using namespace clang;
using namespace CodeGen;
namespace {
/// BaseOffset - Represents an offset from a derived class to a direct or
/// indirect base class.
struct BaseOffset {
/// DerivedClass - The derived class.
const CXXRecordDecl *DerivedClass;
/// VirtualBase - If the path from the derived class to the base class
/// involves a virtual base class, this holds its declaration.
const CXXRecordDecl *VirtualBase;
/// NonVirtualOffset - The offset from the derived class to the base class.
/// (Or the offset from the virtual base class to the base class, if the
/// path from the derived class to the base class involves a virtual base
/// class.
int64_t NonVirtualOffset;
BaseOffset() : DerivedClass(0), VirtualBase(0), NonVirtualOffset(0) { }
BaseOffset(const CXXRecordDecl *DerivedClass,
const CXXRecordDecl *VirtualBase, int64_t NonVirtualOffset)
: DerivedClass(DerivedClass), VirtualBase(VirtualBase),
NonVirtualOffset(NonVirtualOffset) { }
bool isEmpty() const { return !NonVirtualOffset && !VirtualBase; }
};
/// FinalOverriders - Contains the final overrider member functions for all
/// member functions in the base subobjects of a class.
class FinalOverriders {
public:
/// OverriderInfo - Information about a final overrider.
struct OverriderInfo {
/// Method - The method decl of the overrider.
const CXXMethodDecl *Method;
/// BaseOffset - the base offset of the overrider.
uint64_t BaseOffset;
OverriderInfo() : Method(0), BaseOffset(0) { }
};
private:
/// MostDerivedClass - The most derived class for which the final overriders
/// are stored.
const CXXRecordDecl *MostDerivedClass;
ASTContext &Context;
/// MostDerivedClassLayout - the AST record layout of the most derived class.
const ASTRecordLayout &MostDerivedClassLayout;
/// BaseSubobjectMethodPairTy - Uniquely identifies a member function
/// in a base subobject.
typedef std::pair<BaseSubobject, const CXXMethodDecl *>
BaseSubobjectMethodPairTy;
typedef llvm::DenseMap<BaseSubobjectMethodPairTy,
OverriderInfo> OverridersMapTy;
/// OverridersMap - The final overriders for all virtual member functions of
/// all the base subobjects of the most derived class.
OverridersMapTy OverridersMap;
/// VisitedVirtualBases - A set of all the visited virtual bases, used to
/// avoid visiting virtual bases more than once.
llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBases;
typedef llvm::DenseMap<BaseSubobjectMethodPairTy, BaseOffset>
AdjustmentOffsetsMapTy;
/// ReturnAdjustments - Holds return adjustments for all the overriders that
/// need to perform return value adjustments.
AdjustmentOffsetsMapTy ReturnAdjustments;
/// ThisAdjustments - Holds 'this' adjustments for all the overriders that
/// need them.
AdjustmentOffsetsMapTy ThisAdjustments;
typedef llvm::SmallVector<uint64_t, 1> OffsetVectorTy;
/// SubobjectOffsetsMapTy - This map is used for keeping track of all the
/// base subobject offsets that a single class declaration might refer to.
///
/// For example, in:
///
/// struct A { virtual void f(); };
/// struct B1 : A { };
/// struct B2 : A { };
/// struct C : B1, B2 { virtual void f(); };
///
/// when we determine that C::f() overrides A::f(), we need to update the
/// overriders map for both A-in-B1 and A-in-B2 and the subobject offsets map
/// will have the subobject offsets for both A copies.
typedef llvm::DenseMap<const CXXRecordDecl *, OffsetVectorTy>
SubobjectOffsetsMapTy;
/// ComputeFinalOverriders - Compute the final overriders for a given base
/// subobject (and all its direct and indirect bases).
void ComputeFinalOverriders(BaseSubobject Base,
bool BaseSubobjectIsVisitedVBase,
SubobjectOffsetsMapTy &Offsets);
/// AddOverriders - Add the final overriders for this base subobject to the
/// map of final overriders.
void AddOverriders(BaseSubobject Base, SubobjectOffsetsMapTy &Offsets);
/// PropagateOverrider - Propagate the NewMD overrider to all the functions
/// that OldMD overrides. For example, if we have:
///
/// struct A { virtual void f(); };
/// struct B : A { virtual void f(); };
/// struct C : B { virtual void f(); };
///
/// and we want to override B::f with C::f, we also need to override A::f with
/// C::f.
void PropagateOverrider(const CXXMethodDecl *OldMD,
BaseSubobject NewBase,
const CXXMethodDecl *NewMD,
SubobjectOffsetsMapTy &Offsets);
/// ComputeThisAdjustmentBaseOffset - Compute the base offset for adjusting
/// the 'this' pointer from the base subobject to the derived subobject.
BaseOffset ComputeThisAdjustmentBaseOffset(BaseSubobject Base,
BaseSubobject Derived);
static void MergeSubobjectOffsets(const SubobjectOffsetsMapTy &NewOffsets,
SubobjectOffsetsMapTy &Offsets);
public:
explicit FinalOverriders(const CXXRecordDecl *MostDerivedClass);
/// getOverrider - Get the final overrider for the given method declaration in
/// the given base subobject.
OverriderInfo getOverrider(BaseSubobject Base,
const CXXMethodDecl *MD) const {
assert(OverridersMap.count(std::make_pair(Base, MD)) &&
"Did not find overrider!");
return OverridersMap.lookup(std::make_pair(Base, MD));
}
/// getReturnAdjustmentOffset - Get the return adjustment offset for the
/// method decl in the given base subobject. Returns an empty base offset if
/// no adjustment is needed.
BaseOffset getReturnAdjustmentOffset(BaseSubobject Base,
const CXXMethodDecl *MD) const {
return ReturnAdjustments.lookup(std::make_pair(Base, MD));
}
/// getThisAdjustmentOffset - Get the 'this' pointer adjustment offset for the
/// method decl in the given base subobject. Returns an empty base offset if
/// no adjustment is needed.
BaseOffset getThisAdjustmentOffset(BaseSubobject Base,
const CXXMethodDecl *MD) const {
return ThisAdjustments.lookup(std::make_pair(Base, MD));
}
/// dump - dump the final overriders.
void dump() {
assert(VisitedVirtualBases.empty() &&
"Visited virtual bases aren't empty!");
dump(llvm::errs(), BaseSubobject(MostDerivedClass, 0));
VisitedVirtualBases.clear();
}
/// dump - dump the final overriders for a base subobject, and all its direct
/// and indirect base subobjects.
void dump(llvm::raw_ostream &Out, BaseSubobject Base);
};
FinalOverriders::FinalOverriders(const CXXRecordDecl *MostDerivedClass)
: MostDerivedClass(MostDerivedClass),
Context(MostDerivedClass->getASTContext()),
MostDerivedClassLayout(Context.getASTRecordLayout(MostDerivedClass)) {
// Compute the final overriders.
SubobjectOffsetsMapTy Offsets;
ComputeFinalOverriders(BaseSubobject(MostDerivedClass, 0),
/*BaseSubobjectIsVisitedVBase=*/false, Offsets);
VisitedVirtualBases.clear();
// And dump them (for now).
dump();
// Also dump the base offsets (for now).
for (SubobjectOffsetsMapTy::const_iterator I = Offsets.begin(),
E = Offsets.end(); I != E; ++I) {
const OffsetVectorTy& OffsetVector = I->second;
llvm::errs() << "Base offsets for ";
llvm::errs() << I->first->getQualifiedNameAsString() << '\n';
for (unsigned I = 0, E = OffsetVector.size(); I != E; ++I)
llvm::errs() << " " << I << " - " << OffsetVector[I] << '\n';
}
}
void FinalOverriders::AddOverriders(BaseSubobject Base,
SubobjectOffsetsMapTy &Offsets) {
const CXXRecordDecl *RD = Base.getBase();
for (CXXRecordDecl::method_iterator I = RD->method_begin(),
E = RD->method_end(); I != E; ++I) {
const CXXMethodDecl *MD = *I;
if (!MD->isVirtual())
continue;
// First, propagate the overrider.
PropagateOverrider(MD, Base, MD, Offsets);
// Add the overrider as the final overrider of itself.
OverriderInfo& Overrider = OverridersMap[std::make_pair(Base, MD)];
assert(!Overrider.Method && "Overrider should not exist yet!");
Overrider.BaseOffset = Base.getBaseOffset();
Overrider.Method = MD;
}
}
static BaseOffset ComputeBaseOffset(ASTContext &Context,
const CXXRecordDecl *DerivedRD,
const CXXBasePath &Path) {
int64_t NonVirtualOffset = 0;
unsigned NonVirtualStart = 0;
const CXXRecordDecl *VirtualBase = 0;
// First, look for the virtual base class.
for (unsigned I = 0, E = Path.size(); I != E; ++I) {
const CXXBasePathElement &Element = Path[I];
if (Element.Base->isVirtual()) {
// FIXME: Can we break when we find the first virtual base?
// (If we can't, can't we just iterate over the path in reverse order?)
NonVirtualStart = I + 1;
QualType VBaseType = Element.Base->getType();
VirtualBase =
cast<CXXRecordDecl>(VBaseType->getAs<RecordType>()->getDecl());
}
}
// Now compute the non-virtual offset.
for (unsigned I = NonVirtualStart, E = Path.size(); I != E; ++I) {
const CXXBasePathElement &Element = Path[I];
// Check the base class offset.
const ASTRecordLayout &Layout = Context.getASTRecordLayout(Element.Class);
const RecordType *BaseType = Element.Base->getType()->getAs<RecordType>();
const CXXRecordDecl *Base = cast<CXXRecordDecl>(BaseType->getDecl());
NonVirtualOffset += Layout.getBaseClassOffset(Base);
}
// FIXME: This should probably use CharUnits or something. Maybe we should
// even change the base offsets in ASTRecordLayout to be specified in
// CharUnits.
return BaseOffset(DerivedRD, VirtualBase, NonVirtualOffset / 8);
}
static BaseOffset ComputeBaseOffset(ASTContext &Context,
const CXXRecordDecl *BaseRD,
const CXXRecordDecl *DerivedRD) {
CXXBasePaths Paths(/*FindAmbiguities=*/false,
/*RecordPaths=*/true, /*DetectVirtual=*/false);
if (!const_cast<CXXRecordDecl *>(DerivedRD)->
isDerivedFrom(const_cast<CXXRecordDecl *>(BaseRD), Paths)) {
assert(false && "Class must be derived from the passed in base class!");
return BaseOffset();
}
return ComputeBaseOffset(Context, DerivedRD, Paths.front());
}
static BaseOffset
ComputeReturnAdjustmentBaseOffset(ASTContext &Context,
const CXXMethodDecl *DerivedMD,
const CXXMethodDecl *BaseMD) {
const FunctionType *BaseFT = BaseMD->getType()->getAs<FunctionType>();
const FunctionType *DerivedFT = DerivedMD->getType()->getAs<FunctionType>();
// Canonicalize the return types.
CanQualType CanDerivedReturnType =
Context.getCanonicalType(DerivedFT->getResultType());
CanQualType CanBaseReturnType =
Context.getCanonicalType(BaseFT->getResultType());
assert(CanDerivedReturnType->getTypeClass() ==
CanBaseReturnType->getTypeClass() &&
"Types must have same type class!");
if (CanDerivedReturnType == CanBaseReturnType) {
// No adjustment needed.
return BaseOffset();
}
if (isa<ReferenceType>(CanDerivedReturnType)) {
CanDerivedReturnType =
CanDerivedReturnType->getAs<ReferenceType>()->getPointeeType();
CanBaseReturnType =
CanBaseReturnType->getAs<ReferenceType>()->getPointeeType();
} else if (isa<PointerType>(CanDerivedReturnType)) {
CanDerivedReturnType =
CanDerivedReturnType->getAs<PointerType>()->getPointeeType();
CanBaseReturnType =
CanBaseReturnType->getAs<PointerType>()->getPointeeType();
} else {
assert(false && "Unexpected return type!");
}
// We need to compare unqualified types here; consider
// const T *Base::foo();
// T *Derived::foo();
if (CanDerivedReturnType.getUnqualifiedType() ==
CanBaseReturnType.getUnqualifiedType()) {
// No adjustment needed.
return BaseOffset();
}
const CXXRecordDecl *DerivedRD =
cast<CXXRecordDecl>(cast<RecordType>(CanDerivedReturnType)->getDecl());
const CXXRecordDecl *BaseRD =
cast<CXXRecordDecl>(cast<RecordType>(CanBaseReturnType)->getDecl());
return ComputeBaseOffset(Context, BaseRD, DerivedRD);
}
BaseOffset
FinalOverriders::ComputeThisAdjustmentBaseOffset(BaseSubobject Base,
BaseSubobject Derived) {
const CXXRecordDecl *BaseRD = Base.getBase();
const CXXRecordDecl *DerivedRD = Derived.getBase();
CXXBasePaths Paths(/*FindAmbiguities=*/true,
/*RecordPaths=*/true, /*DetectVirtual=*/true);
if (!const_cast<CXXRecordDecl *>(DerivedRD)->
isDerivedFrom(const_cast<CXXRecordDecl *>(BaseRD), Paths)) {
assert(false && "Class must be derived from the passed in base class!");
return BaseOffset();
}
// We have to go through all the paths, and see which one leads us to the
// right base subobject.
for (CXXBasePaths::const_paths_iterator I = Paths.begin(), E = Paths.end();
I != E; ++I) {
BaseOffset Offset = ComputeBaseOffset(Context, DerivedRD, *I);
// FIXME: Should not use * 8 here.
uint64_t OffsetToBaseSubobject = Offset.NonVirtualOffset * 8;
if (Offset.VirtualBase) {
// If we have a virtual base class, the non-virtual offset is relative
// to the virtual base class offset.
const ASTRecordLayout &MostDerivedClassLayout =
Context.getASTRecordLayout(MostDerivedClass);
/// Get the virtual base offset, relative to the most derived class
/// layout.
OffsetToBaseSubobject +=
MostDerivedClassLayout.getVBaseClassOffset(Offset.VirtualBase);
} else {
// Otherwise, the non-virtual offset is relative to the derived class
// offset.
OffsetToBaseSubobject += Derived.getBaseOffset();
}
// Check if this path gives us the right base subobject.
if (OffsetToBaseSubobject == Base.getBaseOffset()) {
// Since we're going from the base class _to_ the derived class, we'll
// invert the non-virtual offset here.
Offset.NonVirtualOffset = -Offset.NonVirtualOffset;
return Offset;
}
}
return BaseOffset();
}
void FinalOverriders::PropagateOverrider(const CXXMethodDecl *OldMD,
BaseSubobject NewBase,
const CXXMethodDecl *NewMD,
SubobjectOffsetsMapTy &Offsets) {
for (CXXMethodDecl::method_iterator I = OldMD->begin_overridden_methods(),
E = OldMD->end_overridden_methods(); I != E; ++I) {
const CXXMethodDecl *OverriddenMD = *I;
const CXXRecordDecl *OverriddenRD = OverriddenMD->getParent();
// We want to override OverriddenMD in all subobjects, for example:
//
/// struct A { virtual void f(); };
/// struct B1 : A { };
/// struct B2 : A { };
/// struct C : B1, B2 { virtual void f(); };
///
/// When overriding A::f with C::f we need to do so in both A subobjects.
const OffsetVectorTy &OffsetVector = Offsets[OverriddenRD];
// Go through all the subobjects.
for (unsigned I = 0, E = OffsetVector.size(); I != E; ++I) {
uint64_t Offset = OffsetVector[I];
BaseSubobject OverriddenSubobject = BaseSubobject(OverriddenRD, Offset);
BaseSubobjectMethodPairTy SubobjectAndMethod =
std::make_pair(OverriddenSubobject, OverriddenMD);
OverriderInfo &Overrider = OverridersMap[SubobjectAndMethod];
assert(Overrider.Method && "Did not find existing overrider!");
// Check if we need return adjustments or base adjustments.
// (We don't want to do this for pure virtual member functions).
if (!NewMD->isPure()) {
// Get the return adjustment base offset.
BaseOffset ReturnBaseOffset =
ComputeReturnAdjustmentBaseOffset(Context, NewMD, OverriddenMD);
if (!ReturnBaseOffset.isEmpty()) {
// Store the return adjustment base offset.
ReturnAdjustments[SubobjectAndMethod] = ReturnBaseOffset;
}
// Check if we need a 'this' adjustment base offset as well.
if (Offset != NewBase.getBaseOffset()) {
BaseOffset ThisBaseOffset =
ComputeThisAdjustmentBaseOffset(OverriddenSubobject,
NewBase);
assert(!ThisBaseOffset.isEmpty() &&
"Should not get an empty 'this' adjustment!");
ThisAdjustments[SubobjectAndMethod] = ThisBaseOffset;
}
}
// Set the new overrider.
Overrider.BaseOffset = NewBase.getBaseOffset();
Overrider.Method = NewMD;
// And propagate it further.
PropagateOverrider(OverriddenMD, NewBase, NewMD, Offsets);
}
}
}
void
FinalOverriders::MergeSubobjectOffsets(const SubobjectOffsetsMapTy &NewOffsets,
SubobjectOffsetsMapTy &Offsets) {
// Iterate over the new offsets.
for (SubobjectOffsetsMapTy::const_iterator I = NewOffsets.begin(),
E = NewOffsets.end(); I != E; ++I) {
const CXXRecordDecl *NewRD = I->first;
const OffsetVectorTy& NewOffsetVector = I->second;
OffsetVectorTy &OffsetVector = Offsets[NewRD];
if (OffsetVector.empty()) {
// There were no previous offsets in this vector, just insert all entries
// from the new offset vector.
OffsetVector.append(NewOffsetVector.begin(), NewOffsetVector.end());
continue;
}
// We need to merge the new offsets vector into the old, but we don't want
// to have duplicate entries. Do this by inserting the old offsets in a set
// so they'll be unique. After this, we iterate over the new offset vector
// and only append elements that aren't in the set.
// First, add the existing offsets to the set.
llvm::SmallSet<uint64_t, 4> OffsetSet;
for (unsigned I = 0, E = OffsetVector.size(); I != E; ++I) {
bool Inserted = OffsetSet.insert(OffsetVector[I]);
if (!Inserted)
assert(false && "Set of offsets should be unique!");
}
// Next, only add the new offsets if they are not already in the set.
for (unsigned I = 0, E = NewOffsetVector.size(); I != E; ++I) {
uint64_t Offset = NewOffsetVector[I];
if (OffsetSet.count(Offset)) {
// Ignore the offset.
continue;
}
// Otherwise, add it to the offsets vector.
OffsetVector.push_back(Offset);
}
}
}
void FinalOverriders::ComputeFinalOverriders(BaseSubobject Base,
bool BaseSubobjectIsVisitedVBase,
SubobjectOffsetsMapTy &Offsets) {
const CXXRecordDecl *RD = Base.getBase();
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
SubobjectOffsetsMapTy NewOffsets;
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// Ignore bases that don't have any virtual member functions.
if (!BaseDecl->isPolymorphic())
continue;
bool IsVisitedVirtualBase = false;
uint64_t BaseOffset;
if (I->isVirtual()) {
if (!VisitedVirtualBases.insert(BaseDecl))
IsVisitedVirtualBase = true;
BaseOffset = MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
} else {
BaseOffset = Layout.getBaseClassOffset(BaseDecl) + Base.getBaseOffset();
}
// Compute the final overriders for this base.
// We always want to compute the final overriders, even if the base is a
// visited virtual base. Consider:
//
// struct A {
// virtual void f();
// virtual void g();
// };
//
// struct B : virtual A {
// void f();
// };
//
// struct C : virtual A {
// void g ();
// };
//
// struct D : B, C { };
//
// Here, we still want to compute the overriders for A as a base of C,
// because otherwise we'll miss that C::g overrides A::f.
ComputeFinalOverriders(BaseSubobject(BaseDecl, BaseOffset),
IsVisitedVirtualBase, NewOffsets);
}
/// Now add the overriders for this particular subobject.
/// (We don't want to do this more than once for a virtual base).
if (!BaseSubobjectIsVisitedVBase)
AddOverriders(Base, NewOffsets);
// And merge the newly discovered subobject offsets.
MergeSubobjectOffsets(NewOffsets, Offsets);
/// Finally, add the offset for our own subobject.
Offsets[RD].push_back(Base.getBaseOffset());
}
void FinalOverriders::dump(llvm::raw_ostream &Out, BaseSubobject Base) {
const CXXRecordDecl *RD = Base.getBase();
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// Ignore bases that don't have any virtual member functions.
if (!BaseDecl->isPolymorphic())
continue;
uint64_t BaseOffset;
if (I->isVirtual()) {
if (!VisitedVirtualBases.insert(BaseDecl)) {
// We've visited this base before.
continue;
}
BaseOffset = MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
} else {
BaseOffset = Layout.getBaseClassOffset(BaseDecl) +
Base.getBaseOffset();
}
dump(Out, BaseSubobject(BaseDecl, BaseOffset));
}
Out << "Final overriders for (" << RD->getQualifiedNameAsString() << ", ";
Out << Base.getBaseOffset() << ")\n";
// Now dump the overriders for this base subobject.
for (CXXRecordDecl::method_iterator I = RD->method_begin(),
E = RD->method_end(); I != E; ++I) {
const CXXMethodDecl *MD = *I;
if (!MD->isVirtual())
continue;
OverriderInfo Overrider = getOverrider(Base, MD);
Out << " " << MD->getQualifiedNameAsString() << " - ";
Out << Overrider.Method->getQualifiedNameAsString();
AdjustmentOffsetsMapTy::const_iterator AI =
ReturnAdjustments.find(std::make_pair(Base, MD));
if (AI != ReturnAdjustments.end()) {
const BaseOffset &Offset = AI->second;
Out << " [ret-adj: ";
if (Offset.VirtualBase)
Out << Offset.VirtualBase->getQualifiedNameAsString() << " vbase, ";
Out << Offset.NonVirtualOffset << " nv]";
}
AI = ThisAdjustments.find(std::make_pair(Base, MD));
if (AI != ThisAdjustments.end()) {
const BaseOffset &Offset = AI->second;
Out << " [this-adj: ";
if (Offset.VirtualBase)
Out << Offset.VirtualBase->getQualifiedNameAsString() << " vbase, ";
Out << Offset.NonVirtualOffset << " nv]";
}
Out << "\n";
}
}
/// VtableComponent - Represents a single component in a vtable.
class VtableComponent {
public:
enum Kind {
CK_VCallOffset,
CK_VBaseOffset,
CK_OffsetToTop,
CK_RTTI,
CK_FunctionPointer,
/// CK_CompleteDtorPointer - A pointer to the complete destructor.
CK_CompleteDtorPointer,
/// CK_DeletingDtorPointer - A pointer to the deleting destructor.
CK_DeletingDtorPointer,
/// CK_UnusedFunctionPointer - In some cases, a vtable function pointer
/// will end up never being called. Such vtable function pointers are
/// represented as a CK_UnusedFunctionPointer.
CK_UnusedFunctionPointer
};
static VtableComponent MakeVCallOffset(int64_t Offset) {
return VtableComponent(CK_VCallOffset, Offset);
}
static VtableComponent MakeVBaseOffset(int64_t Offset) {
return VtableComponent(CK_VBaseOffset, Offset);
}
static VtableComponent MakeOffsetToTop(int64_t Offset) {
return VtableComponent(CK_OffsetToTop, Offset);
}
static VtableComponent MakeRTTI(const CXXRecordDecl *RD) {
return VtableComponent(CK_RTTI, reinterpret_cast<uintptr_t>(RD));
}
static VtableComponent MakeFunction(const CXXMethodDecl *MD) {
assert(!isa<CXXDestructorDecl>(MD) &&
"Don't use MakeFunction with destructors!");
return VtableComponent(CK_FunctionPointer,
reinterpret_cast<uintptr_t>(MD));
}
static VtableComponent MakeCompleteDtor(const CXXDestructorDecl *DD) {
return VtableComponent(CK_CompleteDtorPointer,
reinterpret_cast<uintptr_t>(DD));
}
static VtableComponent MakeDeletingDtor(const CXXDestructorDecl *DD) {
return VtableComponent(CK_DeletingDtorPointer,
reinterpret_cast<uintptr_t>(DD));
}
static VtableComponent MakeUnusedFunction(const CXXMethodDecl *MD) {
assert(!isa<CXXDestructorDecl>(MD) &&
"Don't use MakeUnusedFunction with destructors!");
return VtableComponent(CK_UnusedFunctionPointer,
reinterpret_cast<uintptr_t>(MD));
}
/// getKind - Get the kind of this vtable component.
Kind getKind() const {
return (Kind)(Value & 0x7);
}
int64_t getVCallOffset() const {
assert(getKind() == CK_VCallOffset && "Invalid component kind!");
return getOffset();
}
int64_t getVBaseOffset() const {
assert(getKind() == CK_VBaseOffset && "Invalid component kind!");
return getOffset();
}
int64_t getOffsetToTop() const {
assert(getKind() == CK_OffsetToTop && "Invalid component kind!");
return getOffset();
}
const CXXRecordDecl *getRTTIDecl() const {
assert(getKind() == CK_RTTI && "Invalid component kind!");
return reinterpret_cast<CXXRecordDecl *>(getPointer());
}
const CXXMethodDecl *getFunctionDecl() const {
assert(getKind() == CK_FunctionPointer);
return reinterpret_cast<CXXMethodDecl *>(getPointer());
}
const CXXDestructorDecl *getDestructorDecl() const {
assert((getKind() == CK_CompleteDtorPointer ||
getKind() == CK_DeletingDtorPointer) && "Invalid component kind!");
return reinterpret_cast<CXXDestructorDecl *>(getPointer());
}
const CXXMethodDecl *getUnusedFunctionDecl() const {
assert(getKind() == CK_UnusedFunctionPointer);
return reinterpret_cast<CXXMethodDecl *>(getPointer());
}
private:
VtableComponent(Kind ComponentKind, int64_t Offset) {
assert((ComponentKind == CK_VCallOffset ||
ComponentKind == CK_VBaseOffset ||
ComponentKind == CK_OffsetToTop) && "Invalid component kind!");
assert(Offset <= ((1LL << 56) - 1) && "Offset is too big!");
Value = ((Offset << 3) | ComponentKind);
}
VtableComponent(Kind ComponentKind, uintptr_t Ptr) {
assert((ComponentKind == CK_RTTI ||
ComponentKind == CK_FunctionPointer ||
ComponentKind == CK_CompleteDtorPointer ||
ComponentKind == CK_DeletingDtorPointer ||
ComponentKind == CK_UnusedFunctionPointer) &&
"Invalid component kind!");
assert((Ptr & 7) == 0 && "Pointer not sufficiently aligned!");
Value = Ptr | ComponentKind;
}
int64_t getOffset() const {
assert((getKind() == CK_VCallOffset || getKind() == CK_VBaseOffset ||
getKind() == CK_OffsetToTop) && "Invalid component kind!");
return Value >> 3;
}
uintptr_t getPointer() const {
assert((getKind() == CK_RTTI ||
getKind() == CK_FunctionPointer ||
getKind() == CK_CompleteDtorPointer ||
getKind() == CK_DeletingDtorPointer ||
getKind() == CK_UnusedFunctionPointer) &&
"Invalid component kind!");
return static_cast<uintptr_t>(Value & ~7ULL);
}
/// The kind is stored in the lower 3 bits of the value. For offsets, we
/// make use of the facts that classes can't be larger than 2^55 bytes,
/// so we store the offset in the lower part of the 61 bytes that remain.
/// (The reason that we're not simply using a PointerIntPair here is that we
/// need the offsets to be 64-bit, even when on a 32-bit machine).
int64_t Value;
};
/// VCallOffsetMap - Keeps track of vcall offsets when building a vtable.
struct VCallOffsetMap {
typedef std::pair<const CXXMethodDecl *, int64_t> MethodAndOffsetPairTy;
/// Offsets - Keeps track of methods and their offsets.
// FIXME: This should be a real map and not a vector.
llvm::SmallVector<MethodAndOffsetPairTy, 16> Offsets;
/// MethodsCanShareVCallOffset - Returns whether two virtual member functions
/// can share the same vcall offset.
static bool MethodsCanShareVCallOffset(const CXXMethodDecl *LHS,
const CXXMethodDecl *RHS);
public:
/// AddVCallOffset - Adds a vcall offset to the map. Returns true if the
/// add was successful, or false if there was already a member function with
/// the same signature in the map.
bool AddVCallOffset(const CXXMethodDecl *MD, int64_t OffsetOffset);
/// getVCallOffsetOffset - Returns the vcall offset offset (relative to the
/// vtable address point) for the given virtual member function.
int64_t getVCallOffsetOffset(const CXXMethodDecl *MD);
/// clear - Clear the offset map.
void clear() { Offsets.clear(); }
};
bool VCallOffsetMap::MethodsCanShareVCallOffset(const CXXMethodDecl *LHS,
const CXXMethodDecl *RHS) {
assert(LHS->isVirtual() && "LHS must be virtual!");
assert(RHS->isVirtual() && "LHS must be virtual!");
// FIXME: We need to check more things here.
DeclarationName LHSName = LHS->getDeclName();
DeclarationName RHSName = RHS->getDeclName();
if (LHSName.getNameKind() != LHSName.getNameKind())
return false;
switch (LHSName.getNameKind()) {
default:
assert(false && "Unhandled name kind!");
case DeclarationName::Identifier:
if (LHSName.getAsIdentifierInfo() != RHSName.getAsIdentifierInfo())
return false;
}
return true;
}
bool VCallOffsetMap::AddVCallOffset(const CXXMethodDecl *MD,
int64_t OffsetOffset) {
// Check if we can reuse an offset.
for (unsigned I = 0, E = Offsets.size(); I != E; ++I) {
if (MethodsCanShareVCallOffset(Offsets[I].first, MD))
return false;
}
// Add the offset.
Offsets.push_back(MethodAndOffsetPairTy(MD, OffsetOffset));
return true;
}
int64_t VCallOffsetMap::getVCallOffsetOffset(const CXXMethodDecl *MD) {
// Look for an offset.
for (unsigned I = 0, E = Offsets.size(); I != E; ++I) {
if (MethodsCanShareVCallOffset(Offsets[I].first, MD))
return Offsets[I].second;
}
assert(false && "Should always find a vcall offset offset!");
return 0;
}
/// VtableBuilder - Class for building vtable layout information.
class VtableBuilder {
public:
/// PrimaryBasesSetTy - A set of direct and indirect primary bases.
typedef llvm::SmallPtrSet<const CXXRecordDecl *, 8> PrimaryBasesSetTy;
private:
/// VtableInfo - Global vtable information.
CGVtableInfo &VtableInfo;
/// MostDerivedClass - The most derived class for which we're building this
/// vtable.
const CXXRecordDecl *MostDerivedClass;
/// Context - The ASTContext which we will use for layout information.
ASTContext &Context;
/// FinalOverriders - The final overriders of the most derived class.
FinalOverriders Overriders;
/// VCallAndVBaseOffsets - The vcall and vbase offset, of the vtable we're
// building (in reverse order).
llvm::SmallVector<VtableComponent, 64> VCallAndVBaseOffsets;
/// VCallOffsets - Keeps track of vcall offsets for the current vtable.
VCallOffsetMap VCallOffsets;
/// Components - The components of the vtable being built.
llvm::SmallVector<VtableComponent, 64> Components;
/// AddressPoints - Address points for the vtable being built.
CGVtableInfo::AddressPointsMapTy AddressPoints;
/// ReturnAdjustment - A return adjustment.
struct ReturnAdjustment {
/// NonVirtual - The non-virtual adjustment from the derived object to its
/// nearest virtual base.
int64_t NonVirtual;
/// VBaseOffsetOffset - The offset (in bytes), relative to the address point
/// of the virtual base class offset.
int64_t VBaseOffsetOffset;
ReturnAdjustment() : NonVirtual(0), VBaseOffsetOffset(0) { }
bool isEmpty() const { return !NonVirtual && !VBaseOffsetOffset; }
};
/// ReturnAdjustments - The return adjustments needed in this vtable.
llvm::SmallVector<std::pair<uint64_t, ReturnAdjustment>, 16>
ReturnAdjustments;
/// ThisAdjustment - A 'this' pointer adjustment thunk.
struct ThisAdjustment {
/// NonVirtual - The non-virtual adjustment from the derived object to its
/// nearest virtual base.
int64_t NonVirtual;
/// VCallOffsetOffset - The offset (in bytes), relative to the address point
/// of the virtual call offset.
int64_t VCallOffsetOffset;
ThisAdjustment() : NonVirtual(0), VCallOffsetOffset(0) { }
bool isEmpty() const { return !NonVirtual && !VCallOffsetOffset; }
};
/// ThisAdjustments - The 'this' pointer adjustments needed in this vtable.
llvm::SmallVector<std::pair<uint64_t, ThisAdjustment>, 16>
ThisAdjustments;
typedef llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBasesSetTy;
/// AddVCallAndVBaseOffsets - Add vcall offsets and vbase offsets for the
/// given base subobject.
void AddVCallAndVBaseOffsets(BaseSubobject Base, bool BaseIsVirtual,
VisitedVirtualBasesSetTy &VBases);
/// AddVCallOffsets - Add vcall offsets for the given base subobject.
void AddVCallOffsets(BaseSubobject Base, uint64_t VBaseOffset);
/// AddVBaseOffsets - Add vbase offsets for the given class.
void AddVBaseOffsets(const CXXRecordDecl *Base, int64_t OffsetToTop,
VisitedVirtualBasesSetTy &VBases);
/// ComputeReturnAdjustment - Compute the return adjustment given a return
/// adjustment base offset.
ReturnAdjustment ComputeReturnAdjustment(BaseOffset Offset);
/// ComputeThisAdjustment - Compute the 'this' pointer adjustment for the
/// given virtual member function and the 'this' pointer adjustment base
/// offset.
ThisAdjustment ComputeThisAdjustment(const CXXMethodDecl *MD,
BaseOffset Offset);
/// AddMethod - Add a single virtual member function to the vtable
/// components vector.
void AddMethod(const CXXMethodDecl *MD, ReturnAdjustment ReturnAdjustment,
ThisAdjustment ThisAdjustment);
/// AddMethods - Add the methods of this base subobject and all its
/// primary bases to the vtable components vector.
void AddMethods(BaseSubobject Base, PrimaryBasesSetTy &PrimaryBases);
// LayoutVtable - Layout the vtable for the most derived class, including its
// secondary vtables and any vtables for virtual bases.
void LayoutVtable();
/// LayoutPrimaryAndAndSecondaryVtables - Layout the primary vtable for the
/// given base subobject, as well as all its secondary vtables.
void LayoutPrimaryAndAndSecondaryVtables(BaseSubobject Base,
bool BaseIsVirtual);
/// LayoutSecondaryVtables - Layout the secondary vtables for the given base
/// subobject.
void LayoutSecondaryVtables(BaseSubobject Base);
/// LayoutVtablesForVirtualBases - Layout vtables for all virtual bases of the
/// given base (excluding any primary bases).
void LayoutVtablesForVirtualBases(const CXXRecordDecl *RD,
VisitedVirtualBasesSetTy &VBases);
public:
VtableBuilder(CGVtableInfo &VtableInfo, const CXXRecordDecl *MostDerivedClass)
: VtableInfo(VtableInfo), MostDerivedClass(MostDerivedClass),
Context(MostDerivedClass->getASTContext()), Overriders(MostDerivedClass) {
LayoutVtable();
}
/// dumpLayout - Dump the vtable layout.
void dumpLayout(llvm::raw_ostream&);
};
/// OverridesMethodInPrimaryBase - Checks whether whether this virtual member
/// function overrides a member function in a direct or indirect primary base.
/// Returns the overridden member function, or null if none was found.
static const CXXMethodDecl *
OverridesMethodInPrimaryBase(const CXXMethodDecl *MD,
VtableBuilder::PrimaryBasesSetTy &PrimaryBases) {
for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(),
E = MD->end_overridden_methods(); I != E; ++I) {
const CXXMethodDecl *OverriddenMD = *I;
const CXXRecordDecl *OverriddenRD = OverriddenMD->getParent();
assert(OverriddenMD->isCanonicalDecl() &&
"Should have the canonical decl of the overridden RD!");
if (PrimaryBases.count(OverriddenRD))
return OverriddenMD;
}
return 0;
}
VtableBuilder::ReturnAdjustment
VtableBuilder::ComputeReturnAdjustment(BaseOffset Offset) {
ReturnAdjustment Adjustment;
if (!Offset.isEmpty()) {
if (Offset.VirtualBase) {
// Get the virtual base offset offset.
Adjustment.VBaseOffsetOffset =
VtableInfo.getVirtualBaseOffsetIndex(Offset.DerivedClass,
Offset.VirtualBase);
// FIXME: Once the assert in getVirtualBaseOffsetIndex is back again,
// we can get rid of this assert.
assert(Adjustment.VBaseOffsetOffset != 0 &&
"Invalid base offset offset!");
}
Adjustment.NonVirtual = Offset.NonVirtualOffset;
}
return Adjustment;
}
VtableBuilder::ThisAdjustment
VtableBuilder::ComputeThisAdjustment(const CXXMethodDecl *MD,
BaseOffset Offset) {
ThisAdjustment Adjustment;
if (!Offset.isEmpty()) {
if (Offset.VirtualBase) {
// Get the vcall offset offset.
Adjustment.VCallOffsetOffset = VCallOffsets.getVCallOffsetOffset(MD);
}
Adjustment.NonVirtual = Offset.NonVirtualOffset;
}
return Adjustment;
}
void
VtableBuilder::AddVCallAndVBaseOffsets(BaseSubobject Base,
bool BaseIsVirtual,
VisitedVirtualBasesSetTy &VBases) {
const ASTRecordLayout &Layout = Context.getASTRecordLayout(Base.getBase());
// Itanium C++ ABI 2.5.2:
// ..in classes sharing a virtual table with a primary base class, the vcall
// and vbase offsets added by the derived class all come before the vcall
// and vbase offsets required by the base class, so that the latter may be
// laid out as required by the base class without regard to additions from
// the derived class(es).
// (Since we're emitting the vcall and vbase offsets in reverse order, we'll
// emit them for the primary base first).
if (const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase()) {
bool PrimaryBaseIsVirtual = Layout.getPrimaryBaseWasVirtual();
AddVCallAndVBaseOffsets(BaseSubobject(PrimaryBase, Base.getBaseOffset()),
PrimaryBaseIsVirtual, VBases);
}
// FIXME: Don't use /8 here.
int64_t OffsetToTop = -(int64_t)Base.getBaseOffset() / 8;
AddVBaseOffsets(Base.getBase(), OffsetToTop, VBases);
// We only want to add vcall offsets for virtual bases.
if (BaseIsVirtual && OffsetToTop != 0)
AddVCallOffsets(Base, Base.getBaseOffset());
}
void VtableBuilder::AddVCallOffsets(BaseSubobject Base, uint64_t VBaseOffset) {
printf("adding call offsets for (%s, %llu) vbase offset %llu\n",
Base.getBase()->getQualifiedNameAsString().c_str(),
Base.getBaseOffset(), VBaseOffset);
const CXXRecordDecl *RD = Base.getBase();
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
// Handle the primary base first.
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
if (PrimaryBase && Layout.getPrimaryBaseWasVirtual()) {
// Get the base offset of the primary base.
uint64_t PrimaryBaseOffset = Base.getBaseOffset() +
Layout.getBaseClassOffset(PrimaryBase);
AddVCallOffsets(BaseSubobject(PrimaryBase, PrimaryBaseOffset),
VBaseOffset);
}
// Add the vcall offsets.
for (CXXRecordDecl::method_iterator I = RD->method_begin(),
E = RD->method_end(); I != E; ++I) {
const CXXMethodDecl *MD = *I;
if (!MD->isVirtual())
continue;
// OffsetIndex is the index of this vcall offset, relative to the vtable
// address point. (We subtract 3 to account for the information just
// above the address point, the RTTI info, the offset to top, and the
// vcall offset itself).
int64_t OffsetIndex = -(int64_t)(3 + VCallAndVBaseOffsets.size());
// FIXME: We shouldn't use / 8 here.
int64_t OffsetOffset = OffsetIndex *
(int64_t)Context.Target.getPointerWidth(0) / 8;
// Don't add a vcall offset if we already have one for this member function
// signature.
if (!VCallOffsets.AddVCallOffset(MD, OffsetOffset))
continue;
// Get the final overrider.
FinalOverriders::OverriderInfo Overrider =
Overriders.getOverrider(Base, MD);
/// The vcall offset is the offset from the virtual base to the object where
/// the function was overridden.
// FIXME: We should not use / 8 here.
int64_t Offset = (int64_t)(Overrider.BaseOffset - VBaseOffset) / 8;
VCallAndVBaseOffsets.push_back(VtableComponent::MakeVCallOffset(Offset));
}
// And iterate over all non-virtual bases (ignoring the primary base).
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
if (I->isVirtual())
continue;
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// Get the base offset of this base.
uint64_t BaseOffset = Base.getBaseOffset() +
Layout.getBaseClassOffset(BaseDecl);
AddVCallOffsets(BaseSubobject(BaseDecl, BaseOffset), VBaseOffset);
}
}
void VtableBuilder::AddVBaseOffsets(const CXXRecordDecl *RD,
int64_t OffsetToTop,
VisitedVirtualBasesSetTy &VBases) {
const ASTRecordLayout &MostDerivedClassLayout =
Context.getASTRecordLayout(MostDerivedClass);
// Add vbase offsets.
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// Check if this is a virtual base that we haven't visited before.
if (I->isVirtual() && VBases.insert(BaseDecl)) {
// FIXME: We shouldn't use / 8 here.
uint64_t Offset =
OffsetToTop + MostDerivedClassLayout.getVBaseClassOffset(BaseDecl) / 8;
VCallAndVBaseOffsets.push_back(VtableComponent::MakeVBaseOffset(Offset));
}
// Check the base class looking for more vbase offsets.
AddVBaseOffsets(BaseDecl, OffsetToTop, VBases);
}
}
void
VtableBuilder::AddMethod(const CXXMethodDecl *MD,
ReturnAdjustment ReturnAdjustment,
ThisAdjustment ThisAdjustment) {
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
assert(ReturnAdjustment.isEmpty() &&
"Destructor can't have return adjustment!");
// Add the 'this' pointer adjustments if necessary.
if (!ThisAdjustment.isEmpty()) {
ThisAdjustments.push_back(std::make_pair(Components.size(),
ThisAdjustment));
ThisAdjustments.push_back(std::make_pair(Components.size() + 1,
ThisAdjustment));
}
// Add both the complete destructor and the deleting destructor.
Components.push_back(VtableComponent::MakeCompleteDtor(DD));
Components.push_back(VtableComponent::MakeDeletingDtor(DD));
} else {
// Add the return adjustment if necessary.
if (!ReturnAdjustment.isEmpty())
ReturnAdjustments.push_back(std::make_pair(Components.size(),
ReturnAdjustment));
// Add the 'this' pointer adjustment if necessary.
if (!ThisAdjustment.isEmpty())
ThisAdjustments.push_back(std::make_pair(Components.size(),
ThisAdjustment));
// Add the function.
Components.push_back(VtableComponent::MakeFunction(MD));
}
}
void
VtableBuilder::AddMethods(BaseSubobject Base, PrimaryBasesSetTy &PrimaryBases) {
const CXXRecordDecl *RD = Base.getBase();
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
if (const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase()) {
if (Layout.getPrimaryBaseWasVirtual())
assert(false && "FIXME: Handle vbases here.");
else
assert(Layout.getBaseClassOffset(PrimaryBase) == 0 &&
"Primary base should have a zero offset!");
AddMethods(BaseSubobject(PrimaryBase, Base.getBaseOffset()), PrimaryBases);
if (!PrimaryBases.insert(PrimaryBase))
assert(false && "Found a duplicate primary base!");
}
// Now go through all virtual member functions and add them.
for (CXXRecordDecl::method_iterator I = RD->method_begin(),
E = RD->method_end(); I != E; ++I) {
const CXXMethodDecl *MD = *I;
if (!MD->isVirtual())
continue;
// Get the final overrider.
FinalOverriders::OverriderInfo Overrider =
Overriders.getOverrider(Base, MD);
// Check if this virtual member function overrides a method in a primary
// base. If this is the case, and the return type doesn't require adjustment
// then we can just use the member function from the primary base.
if (const CXXMethodDecl *OverriddenMD =
OverridesMethodInPrimaryBase(MD, PrimaryBases)) {
if (ComputeReturnAdjustmentBaseOffset(Context, MD,
OverriddenMD).isEmpty())
continue;
}
// Check if this overrider needs a return adjustment.
BaseOffset ReturnAdjustmentOffset =
Overriders.getReturnAdjustmentOffset(Base, MD);
ReturnAdjustment ReturnAdjustment =
ComputeReturnAdjustment(ReturnAdjustmentOffset);
// Check if this overrider needs a 'this' pointer adjustment.
BaseOffset ThisAdjustmentOffset =
Overriders.getThisAdjustmentOffset(Base, MD);
ThisAdjustment ThisAdjustment = ComputeThisAdjustment(Overrider.Method,
ThisAdjustmentOffset);
AddMethod(Overrider.Method, ReturnAdjustment, ThisAdjustment);
}
}
void VtableBuilder::LayoutVtable() {
LayoutPrimaryAndAndSecondaryVtables(BaseSubobject(MostDerivedClass, 0),
/*BaseIsVirtual=*/false);
VisitedVirtualBasesSetTy VBases;
LayoutVtablesForVirtualBases(MostDerivedClass, VBases);
}
void VtableBuilder::LayoutPrimaryAndAndSecondaryVtables(BaseSubobject Base,
bool BaseIsVirtual) {
assert(Base.getBase()->isDynamicClass() && "class does not have a vtable!");
// Add vcall and vbase offsets for this vtable.
VisitedVirtualBasesSetTy VBases;
AddVCallAndVBaseOffsets(Base, BaseIsVirtual, VBases);
// Reverse them and add them to the vtable components.
std::reverse(VCallAndVBaseOffsets.begin(), VCallAndVBaseOffsets.end());
Components.append(VCallAndVBaseOffsets.begin(), VCallAndVBaseOffsets.end());
VCallAndVBaseOffsets.clear();
// Add the offset to top.
// FIXME: This is not going to be right for construction vtables.
// FIXME: We should not use / 8 here.
int64_t OffsetToTop = -(int64_t)Base.getBaseOffset() / 8;
Components.push_back(VtableComponent::MakeOffsetToTop(OffsetToTop));
// Next, add the RTTI.
Components.push_back(VtableComponent::MakeRTTI(MostDerivedClass));
uint64_t AddressPoint = Components.size();
// Now go through all virtual member functions and add them.
PrimaryBasesSetTy PrimaryBases;
AddMethods(Base, PrimaryBases);
// Record the address point.
AddressPoints.insert(std::make_pair(Base, AddressPoint));
// Record the address points for all primary bases.
for (PrimaryBasesSetTy::const_iterator I = PrimaryBases.begin(),
E = PrimaryBases.end(); I != E; ++I) {
const CXXRecordDecl *BaseDecl = *I;
// We know that all the primary bases have the same offset as the base
// subobject.
BaseSubobject PrimaryBase(BaseDecl, Base.getBaseOffset());
AddressPoints.insert(std::make_pair(PrimaryBase, AddressPoint));
}
// Layout secondary vtables.
LayoutSecondaryVtables(Base);
// Clear the vcall offsets.
VCallOffsets.clear();
}
void VtableBuilder::LayoutSecondaryVtables(BaseSubobject Base) {
// Itanium C++ ABI 2.5.2:
// Following the primary virtual table of a derived class are secondary
// virtual tables for each of its proper base classes, except any primary
// base(s) with which it shares its primary virtual table.
const CXXRecordDecl *RD = Base.getBase();
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
// Ignore virtual bases, we'll emit them later.
if (I->isVirtual())
continue;
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// Ignore bases that don't have a vtable.
if (!BaseDecl->isDynamicClass())
continue;
// Get the base offset of this base.
uint64_t BaseOffset = Base.getBaseOffset() +
Layout.getBaseClassOffset(BaseDecl);
// Don't emit a secondary vtable for a primary base. We might however want
// to emit secondary vtables for other bases of this base.
if (BaseDecl == PrimaryBase) {
LayoutSecondaryVtables(BaseSubobject(BaseDecl, BaseOffset));
continue;
}
// Layout the primary vtable (and any secondary vtables) for this base.
LayoutPrimaryAndAndSecondaryVtables(BaseSubobject(BaseDecl, BaseOffset),
/*BaseIsVirtual=*/false);
}
}
void
VtableBuilder::LayoutVtablesForVirtualBases(const CXXRecordDecl *RD,
VisitedVirtualBasesSetTy &VBases) {
// Itanium C++ ABI 2.5.2:
// Then come the virtual base virtual tables, also in inheritance graph
// order, and again excluding primary bases (which share virtual tables with
// the classes for which they are primary).
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// Check if this base needs a vtable. (If it's virtual, and we haven't
// visited it before).
if (I->isVirtual() && BaseDecl->isDynamicClass() &&
BaseDecl != PrimaryBase && VBases.insert(BaseDecl)) {
const ASTRecordLayout &MostDerivedClassLayout =
Context.getASTRecordLayout(MostDerivedClass);
uint64_t BaseOffset =
MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
LayoutPrimaryAndAndSecondaryVtables(BaseSubobject(BaseDecl, BaseOffset),
/*BaseIsVirtual=*/true);
}
// We only need to check the base for virtual base vtables if it actually
// has virtual bases.
if (BaseDecl->getNumVBases())
LayoutVtablesForVirtualBases(BaseDecl, VBases);
}
}
/// dumpLayout - Dump the vtable layout.
void VtableBuilder::dumpLayout(llvm::raw_ostream& Out) {
Out << "Vtable for '" << MostDerivedClass->getQualifiedNameAsString();
Out << "' (" << Components.size() << " entries).\n";
// Iterate through the address points and insert them into a new map where
// they are keyed by the index and not the base object.
// Since an address point can be shared by multiple subobjects, we use an
// STL multimap.
std::multimap<uint64_t, BaseSubobject> AddressPointsByIndex;
for (CGVtableInfo::AddressPointsMapTy::const_iterator I =
AddressPoints.begin(), E = AddressPoints.end(); I != E; ++I) {
const BaseSubobject& Base = I->first;
uint64_t Index = I->second;
AddressPointsByIndex.insert(std::make_pair(Index, Base));
}
unsigned NextReturnAdjustmentIndex = 0;
unsigned NextThisAdjustmentIndex = 0;
for (unsigned I = 0, E = Components.size(); I != E; ++I) {
uint64_t Index = I;
if (AddressPointsByIndex.count(I)) {
if (AddressPointsByIndex.count(Index) == 1) {
const BaseSubobject &Base = AddressPointsByIndex.find(Index)->second;
// FIXME: Instead of dividing by 8, we should be using CharUnits.
Out << " -- (" << Base.getBase()->getQualifiedNameAsString();
Out << ", " << Base.getBaseOffset() / 8 << ") vtable address --\n";
} else {
uint64_t BaseOffset =
AddressPointsByIndex.lower_bound(Index)->second.getBaseOffset();
// We store the class names in a set to get a stable order.
std::set<std::string> ClassNames;
for (std::multimap<uint64_t, BaseSubobject>::const_iterator I =
AddressPointsByIndex.lower_bound(Index), E =
AddressPointsByIndex.upper_bound(Index); I != E; ++I) {
assert(I->second.getBaseOffset() == BaseOffset &&
"Invalid base offset!");
const CXXRecordDecl *RD = I->second.getBase();
ClassNames.insert(RD->getQualifiedNameAsString());
}
for (std::set<std::string>::const_iterator I = ClassNames.begin(),
E = ClassNames.end(); I != E; ++I) {
// FIXME: Instead of dividing by 8, we should be using CharUnits.
Out << " -- (" << *I;
Out << ", " << BaseOffset / 8 << ") vtable address --\n";
}
}
}
Out << llvm::format("%4d | ", I);
const VtableComponent &Component = Components[I];
// Dump the component.
switch (Component.getKind()) {
case VtableComponent::CK_VCallOffset:
Out << "vcall_offset (" << Component.getVCallOffset() << ")";
break;
case VtableComponent::CK_VBaseOffset:
Out << "vbase_offset (" << Component.getVBaseOffset() << ")";
break;
case VtableComponent::CK_OffsetToTop:
Out << "offset_to_top (" << Component.getOffsetToTop() << ")";
break;
case VtableComponent::CK_RTTI:
Out << Component.getRTTIDecl()->getQualifiedNameAsString() << " RTTI";
break;
case VtableComponent::CK_FunctionPointer: {
const CXXMethodDecl *MD = Component.getFunctionDecl();
std::string Str =
PredefinedExpr::ComputeName(PredefinedExpr::PrettyFunctionNoVirtual,
MD);
Out << Str;
if (MD->isPure())
Out << " [pure]";
// If this function pointer has a return adjustment, dump it.
if (NextReturnAdjustmentIndex < ReturnAdjustments.size() &&
ReturnAdjustments[NextReturnAdjustmentIndex].first == I) {
const ReturnAdjustment Adjustment =
ReturnAdjustments[NextReturnAdjustmentIndex].second;
Out << "\n [return adjustment: ";
Out << Adjustment.NonVirtual << " non-virtual";
if (Adjustment.VBaseOffsetOffset)
Out << ", " << Adjustment.VBaseOffsetOffset << " vbase offset offset";
Out << ']';
NextReturnAdjustmentIndex++;
}
// If this function pointer has a 'this' pointer adjustment, dump it.
if (NextThisAdjustmentIndex < ThisAdjustments.size() &&
ThisAdjustments[NextThisAdjustmentIndex].first == I) {
const ThisAdjustment Adjustment =
ThisAdjustments[NextThisAdjustmentIndex].second;
Out << "\n [this adjustment: ";
Out << Adjustment.NonVirtual << " non-virtual";
if (Adjustment.VCallOffsetOffset)
Out << ", " << Adjustment.VCallOffsetOffset << " vcall offset offset";
Out << ']';
NextThisAdjustmentIndex++;
}
break;
}
case VtableComponent::CK_CompleteDtorPointer:
case VtableComponent::CK_DeletingDtorPointer: {
bool IsComplete =
Component.getKind() == VtableComponent::CK_CompleteDtorPointer;
const CXXDestructorDecl *DD = Component.getDestructorDecl();
Out << DD->getQualifiedNameAsString();
if (IsComplete)
Out << "() [complete]";
else
Out << "() [deleting]";
if (DD->isPure())
Out << " [pure]";
// If this destructor has a 'this' pointer adjustment, dump it.
if (NextThisAdjustmentIndex < ThisAdjustments.size() &&
ThisAdjustments[NextThisAdjustmentIndex].first == I) {
const ThisAdjustment Adjustment =
ThisAdjustments[NextThisAdjustmentIndex].second;
Out << "\n [this adjustment: ";
Out << Adjustment.NonVirtual << " non-virtual";
if (Adjustment.VCallOffsetOffset)
Out << ", " << Adjustment.VCallOffsetOffset << " vcall offset offset";
Out << ']';
NextThisAdjustmentIndex++;
}
break;
}
case VtableComponent::CK_UnusedFunctionPointer: {
const CXXMethodDecl *MD = Component.getUnusedFunctionDecl();
std::string Str =
PredefinedExpr::ComputeName(PredefinedExpr::PrettyFunctionNoVirtual,
MD);
Out << "[unused] " << Str;
if (MD->isPure())
Out << " [pure]";
}
}
Out << '\n';
}
}
}
namespace {
class OldVtableBuilder {
public:
/// Index_t - Vtable index type.
typedef uint64_t Index_t;
typedef std::vector<std::pair<GlobalDecl,
std::pair<GlobalDecl, ThunkAdjustment> > >
SavedAdjustmentsVectorTy;
private:
// VtableComponents - The components of the vtable being built.
typedef llvm::SmallVector<llvm::Constant *, 64> VtableComponentsVectorTy;
VtableComponentsVectorTy VtableComponents;
const bool BuildVtable;
llvm::Type *Ptr8Ty;
/// MostDerivedClass - The most derived class that this vtable is being
/// built for.
const CXXRecordDecl *MostDerivedClass;
/// LayoutClass - The most derived class used for virtual base layout
/// information.
const CXXRecordDecl *LayoutClass;
/// LayoutOffset - The offset for Class in LayoutClass.
uint64_t LayoutOffset;
/// BLayout - Layout for the most derived class that this vtable is being
/// built for.
const ASTRecordLayout &BLayout;
llvm::SmallSet<const CXXRecordDecl *, 32> IndirectPrimary;
llvm::SmallSet<const CXXRecordDecl *, 32> SeenVBase;
llvm::Constant *rtti;
llvm::LLVMContext &VMContext;
CodeGenModule &CGM; // Per-module state.
llvm::DenseMap<const CXXMethodDecl *, Index_t> VCall;
llvm::DenseMap<GlobalDecl, Index_t> VCallOffset;
llvm::DenseMap<GlobalDecl, Index_t> VCallOffsetForVCall;
// This is the offset to the nearest virtual base
llvm::DenseMap<const CXXMethodDecl *, Index_t> NonVirtualOffset;
llvm::DenseMap<const CXXRecordDecl *, Index_t> VBIndex;
/// PureVirtualFunction - Points to __cxa_pure_virtual.
llvm::Constant *PureVirtualFn;
/// VtableMethods - A data structure for keeping track of methods in a vtable.
/// Can add methods, override methods and iterate in vtable order.
class VtableMethods {
// MethodToIndexMap - Maps from a global decl to the index it has in the
// Methods vector.
llvm::DenseMap<GlobalDecl, uint64_t> MethodToIndexMap;
/// Methods - The methods, in vtable order.
typedef llvm::SmallVector<GlobalDecl, 16> MethodsVectorTy;
MethodsVectorTy Methods;
MethodsVectorTy OrigMethods;
public:
/// AddMethod - Add a method to the vtable methods.
void AddMethod(GlobalDecl GD) {
assert(!MethodToIndexMap.count(GD) &&
"Method has already been added!");
MethodToIndexMap[GD] = Methods.size();
Methods.push_back(GD);
OrigMethods.push_back(GD);
}
/// OverrideMethod - Replace a method with another.
void OverrideMethod(GlobalDecl OverriddenGD, GlobalDecl GD) {
llvm::DenseMap<GlobalDecl, uint64_t>::iterator i
= MethodToIndexMap.find(OverriddenGD);
assert(i != MethodToIndexMap.end() && "Did not find entry!");
// Get the index of the old decl.
uint64_t Index = i->second;
// Replace the old decl with the new decl.
Methods[Index] = GD;
// And add the new.
MethodToIndexMap[GD] = Index;
}
/// getIndex - Gives the index of a passed in GlobalDecl. Returns false if
/// the index couldn't be found.
bool getIndex(GlobalDecl GD, uint64_t &Index) const {
llvm::DenseMap<GlobalDecl, uint64_t>::const_iterator i
= MethodToIndexMap.find(GD);
if (i == MethodToIndexMap.end())
return false;
Index = i->second;
return true;
}
GlobalDecl getOrigMethod(uint64_t Index) const {
return OrigMethods[Index];
}
MethodsVectorTy::size_type size() const {
return Methods.size();
}
void clear() {
MethodToIndexMap.clear();
Methods.clear();
OrigMethods.clear();
}
GlobalDecl operator[](uint64_t Index) const {
return Methods[Index];
}
};
/// Methods - The vtable methods we're currently building.
VtableMethods Methods;
/// ThisAdjustments - For a given index in the vtable, contains the 'this'
/// pointer adjustment needed for a method.
typedef llvm::DenseMap<uint64_t, ThunkAdjustment> ThisAdjustmentsMapTy;
ThisAdjustmentsMapTy ThisAdjustments;
SavedAdjustmentsVectorTy SavedAdjustments;
/// BaseReturnTypes - Contains the base return types of methods who have been
/// overridden with methods whose return types require adjustment. Used for
/// generating covariant thunk information.
typedef llvm::DenseMap<uint64_t, CanQualType> BaseReturnTypesMapTy;
BaseReturnTypesMapTy BaseReturnTypes;
std::vector<Index_t> VCalls;
typedef std::pair<const CXXRecordDecl *, uint64_t> CtorVtable_t;
// subAddressPoints - Used to hold the AddressPoints (offsets) into the built
// vtable for use in computing the initializers for the VTT.
llvm::DenseMap<CtorVtable_t, int64_t> &subAddressPoints;
/// AddressPoints - Address points for this vtable.
CGVtableInfo::AddressPointsMapTy& AddressPoints;
typedef CXXRecordDecl::method_iterator method_iter;
const uint32_t LLVMPointerWidth;
Index_t extra;
typedef std::vector<std::pair<const CXXRecordDecl *, int64_t> > Path_t;
static llvm::DenseMap<CtorVtable_t, int64_t>&
AllocAddressPoint(CodeGenModule &cgm, const CXXRecordDecl *l,
const CXXRecordDecl *c) {
CGVtableInfo::AddrMap_t *&oref = cgm.getVtableInfo().AddressPoints[l];
if (oref == 0)
oref = new CGVtableInfo::AddrMap_t;
llvm::DenseMap<CtorVtable_t, int64_t> *&ref = (*oref)[c];
if (ref == 0)
ref = new llvm::DenseMap<CtorVtable_t, int64_t>;
return *ref;
}
bool DclIsSame(const FunctionDecl *New, const FunctionDecl *Old) {
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 == 0) != (NewTemplate == 0))
return false;
// Is the function New an overload of the function Old?
QualType OldQType = CGM.getContext().getCanonicalType(Old->getType());
QualType NewQType = CGM.getContext().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 true;
FunctionProtoType* OldType = cast<FunctionProtoType>(OldQType);
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->getNumArgs() != NewType->getNumArgs() ||
OldType->isVariadic() != NewType->isVariadic() ||
!std::equal(OldType->arg_type_begin(), OldType->arg_type_end(),
NewType->arg_type_begin())))
return false;
#if 0
// 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.
if (NewTemplate &&
(!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(),
OldTemplate->getTemplateParameters(),
TPL_TemplateMatch) ||
OldType->getResultType() != NewType->getResultType()))
return false;
#endif
// If the function is a class member, its signature includes the
// cv-qualifiers (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.
const CXXMethodDecl* OldMethod = dyn_cast<CXXMethodDecl>(Old);
const CXXMethodDecl* NewMethod = dyn_cast<CXXMethodDecl>(New);
if (OldMethod && NewMethod &&
!OldMethod->isStatic() && !NewMethod->isStatic() &&
OldMethod->getTypeQualifiers() != NewMethod->getTypeQualifiers())
return false;
// The signatures match; this is not an overload.
return true;
}
typedef llvm::DenseMap<const CXXMethodDecl *, const CXXMethodDecl*>
ForwardUnique_t;
ForwardUnique_t ForwardUnique;
llvm::DenseMap<const CXXMethodDecl*, const CXXMethodDecl*> UniqueOverrider;
void BuildUniqueOverrider(const CXXMethodDecl *U, const CXXMethodDecl *MD) {
const CXXMethodDecl *PrevU = UniqueOverrider[MD];
assert(U && "no unique overrider");
if (PrevU == U)
return;
if (PrevU != U && PrevU != 0) {
// If already set, note the two sets as the same
if (0)
printf("%s::%s same as %s::%s\n",
PrevU->getParent()->getNameAsString().c_str(),
PrevU->getNameAsString().c_str(),
U->getParent()->getNameAsString().c_str(),
U->getNameAsString().c_str());
ForwardUnique[PrevU] = U;
return;
}
// Not set, set it now
if (0)
printf("marking %s::%s %p override as %s::%s\n",
MD->getParent()->getNameAsString().c_str(),
MD->getNameAsString().c_str(),
(void*)MD,
U->getParent()->getNameAsString().c_str(),
U->getNameAsString().c_str());
UniqueOverrider[MD] = U;
for (CXXMethodDecl::method_iterator mi = MD->begin_overridden_methods(),
me = MD->end_overridden_methods(); mi != me; ++mi) {
BuildUniqueOverrider(U, *mi);
}
}
void BuildUniqueOverriders(const CXXRecordDecl *RD) {
if (0) printf("walking %s\n", RD->getNameAsCString());
for (CXXRecordDecl::method_iterator i = RD->method_begin(),
e = RD->method_end(); i != e; ++i) {
const CXXMethodDecl *MD = *i;
if (!MD->isVirtual())
continue;
if (UniqueOverrider[MD] == 0) {
// Only set this, if it hasn't been set yet.
BuildUniqueOverrider(MD, MD);
if (0)
printf("top set is %s::%s %p\n",
MD->getParent()->getNameAsString().c_str(),
MD->getNameAsString().c_str(),
(void*)MD);
ForwardUnique[MD] = MD;
}
}
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
BuildUniqueOverriders(Base);
}
}
static int DclCmp(const void *p1, const void *p2) {
const CXXMethodDecl *MD1 = *(const CXXMethodDecl *const *)p1;
const CXXMethodDecl *MD2 = *(const CXXMethodDecl *const *)p2;
return (DeclarationName::compare(MD1->getDeclName(), MD2->getDeclName()));
}
void MergeForwarding() {
typedef llvm::SmallVector<const CXXMethodDecl *, 100> A_t;
A_t A;
for (ForwardUnique_t::iterator I = ForwardUnique.begin(),
E = ForwardUnique.end(); I != E; ++I) {
if (I->first == I->second)
// Only add the roots of all trees
A.push_back(I->first);
}
llvm::array_pod_sort(A.begin(), A.end(), DclCmp);
for (A_t::iterator I = A.begin(),
E = A.end(); I != E; ++I) {
A_t::iterator J = I;
while (++J != E && DclCmp(I, J) == 0)
if (DclIsSame(*I, *J)) {
if (0) printf("connecting %s\n", (*I)->getNameAsString().c_str());
ForwardUnique[*J] = *I;
}
}
}
const CXXMethodDecl *getUnique(const CXXMethodDecl *MD) {
const CXXMethodDecl *U = UniqueOverrider[MD];
assert(U && "unique overrider not found");
while (ForwardUnique.count(U)) {
const CXXMethodDecl *NU = ForwardUnique[U];
if (NU == U) break;
U = NU;
}
return U;
}
GlobalDecl getUnique(GlobalDecl GD) {
const CXXMethodDecl *Unique = getUnique(cast<CXXMethodDecl>(GD.getDecl()));
if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Unique))
return GlobalDecl(CD, GD.getCtorType());
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(Unique))
return GlobalDecl(DD, GD.getDtorType());
return Unique;
}
/// getPureVirtualFn - Return the __cxa_pure_virtual function.
llvm::Constant* getPureVirtualFn() {
if (!PureVirtualFn) {
const llvm::FunctionType *Ty =
llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
/*isVarArg=*/false);
PureVirtualFn = wrap(CGM.CreateRuntimeFunction(Ty, "__cxa_pure_virtual"));
}
return PureVirtualFn;
}
public:
OldVtableBuilder(const CXXRecordDecl *MostDerivedClass,
const CXXRecordDecl *l, uint64_t lo, CodeGenModule &cgm,
bool build, CGVtableInfo::AddressPointsMapTy& AddressPoints)
: BuildVtable(build), MostDerivedClass(MostDerivedClass), LayoutClass(l),
LayoutOffset(lo), BLayout(cgm.getContext().getASTRecordLayout(l)),
rtti(0), VMContext(cgm.getModule().getContext()),CGM(cgm),
PureVirtualFn(0),
subAddressPoints(AllocAddressPoint(cgm, l, MostDerivedClass)),
AddressPoints(AddressPoints),
LLVMPointerWidth(cgm.getContext().Target.getPointerWidth(0))
{
Ptr8Ty = llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext), 0);
if (BuildVtable) {
QualType ClassType = CGM.getContext().getTagDeclType(MostDerivedClass);
rtti = CGM.GetAddrOfRTTIDescriptor(ClassType);
}
BuildUniqueOverriders(MostDerivedClass);
MergeForwarding();
}
// getVtableComponents - Returns a reference to the vtable components.
const VtableComponentsVectorTy &getVtableComponents() const {
return VtableComponents;
}
llvm::DenseMap<const CXXRecordDecl *, uint64_t> &getVBIndex()
{ return VBIndex; }
SavedAdjustmentsVectorTy &getSavedAdjustments()
{ return SavedAdjustments; }
llvm::Constant *wrap(Index_t i) {
llvm::Constant *m;
m = llvm::ConstantInt::get(llvm::Type::getInt64Ty(VMContext), i);
return llvm::ConstantExpr::getIntToPtr(m, Ptr8Ty);
}
llvm::Constant *wrap(llvm::Constant *m) {
return llvm::ConstantExpr::getBitCast(m, Ptr8Ty);
}
//#define D1(x)
#define D1(X) do { if (getenv("CLANG_VTABLE_DEBUG")) { X; } } while (0)
void GenerateVBaseOffsets(const CXXRecordDecl *RD, uint64_t Offset,
bool updateVBIndex, Index_t current_vbindex) {
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
Index_t next_vbindex = current_vbindex;
if (i->isVirtual() && !SeenVBase.count(Base)) {
SeenVBase.insert(Base);
if (updateVBIndex) {
next_vbindex = (ssize_t)(-(VCalls.size()*LLVMPointerWidth/8)
- 3*LLVMPointerWidth/8);
VBIndex[Base] = next_vbindex;
}
int64_t BaseOffset = -(Offset/8) + BLayout.getVBaseClassOffset(Base)/8;
VCalls.push_back((0?700:0) + BaseOffset);
D1(printf(" vbase for %s at %d delta %d most derived %s\n",
Base->getNameAsCString(),
(int)-VCalls.size()-3, (int)BaseOffset,
MostDerivedClass->getNameAsCString()));
}
// We also record offsets for non-virtual bases to closest enclosing
// virtual base. We do this so that we don't have to search
// for the nearst virtual base class when generating thunks.
if (updateVBIndex && VBIndex.count(Base) == 0)
VBIndex[Base] = next_vbindex;
GenerateVBaseOffsets(Base, Offset, updateVBIndex, next_vbindex);
}
}
void StartNewTable() {
SeenVBase.clear();
}
Index_t getNVOffset_1(const CXXRecordDecl *D, const CXXRecordDecl *B,
Index_t Offset = 0) {
if (B == D)
return Offset;
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(D);
for (CXXRecordDecl::base_class_const_iterator i = D->bases_begin(),
e = D->bases_end(); i != e; ++i) {
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
int64_t BaseOffset = 0;
if (!i->isVirtual())
BaseOffset = Offset + Layout.getBaseClassOffset(Base);
int64_t o = getNVOffset_1(Base, B, BaseOffset);
if (o >= 0)
return o;
}
return -1;
}
/// getNVOffset - Returns the non-virtual offset for the given (B) base of the
/// derived class D.
Index_t getNVOffset(QualType qB, QualType qD) {
qD = qD->getPointeeType();
qB = qB->getPointeeType();
CXXRecordDecl *D = cast<CXXRecordDecl>(qD->getAs<RecordType>()->getDecl());
CXXRecordDecl *B = cast<CXXRecordDecl>(qB->getAs<RecordType>()->getDecl());
int64_t o = getNVOffset_1(D, B);
if (o >= 0)
return o;
assert(false && "FIXME: non-virtual base not found");
return 0;
}
/// getVbaseOffset - Returns the index into the vtable for the virtual base
/// offset for the given (B) virtual base of the derived class D.
Index_t getVbaseOffset(QualType qB, QualType qD) {
qD = qD->getPointeeType();
qB = qB->getPointeeType();
CXXRecordDecl *D = cast<CXXRecordDecl>(qD->getAs<RecordType>()->getDecl());
CXXRecordDecl *B = cast<CXXRecordDecl>(qB->getAs<RecordType>()->getDecl());
if (D != MostDerivedClass)
return CGM.getVtableInfo().getVirtualBaseOffsetIndex(D, B);
llvm::DenseMap<const CXXRecordDecl *, Index_t>::iterator i;
i = VBIndex.find(B);
if (i != VBIndex.end())
return i->second;
assert(false && "FIXME: Base not found");
return 0;
}
bool OverrideMethod(GlobalDecl GD, bool MorallyVirtual,
Index_t OverrideOffset, Index_t Offset,
int64_t CurrentVBaseOffset);
/// AppendMethods - Append the current methods to the vtable.
void AppendMethodsToVtable();
llvm::Constant *WrapAddrOf(GlobalDecl GD) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
const llvm::Type *Ty = CGM.getTypes().GetFunctionTypeForVtable(MD);
return wrap(CGM.GetAddrOfFunction(GD, Ty));
}
void OverrideMethods(Path_t *Path, bool MorallyVirtual, int64_t Offset,
int64_t CurrentVBaseOffset) {
for (Path_t::reverse_iterator i = Path->rbegin(),
e = Path->rend(); i != e; ++i) {
const CXXRecordDecl *RD = i->first;
int64_t OverrideOffset = i->second;
for (method_iter mi = RD->method_begin(), me = RD->method_end(); mi != me;
++mi) {
const CXXMethodDecl *MD = *mi;
if (!MD->isVirtual())
continue;
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
// Override both the complete and the deleting destructor.
GlobalDecl CompDtor(DD, Dtor_Complete);
OverrideMethod(CompDtor, MorallyVirtual, OverrideOffset, Offset,
CurrentVBaseOffset);
GlobalDecl DeletingDtor(DD, Dtor_Deleting);
OverrideMethod(DeletingDtor, MorallyVirtual, OverrideOffset, Offset,
CurrentVBaseOffset);
} else {
OverrideMethod(MD, MorallyVirtual, OverrideOffset, Offset,
CurrentVBaseOffset);
}
}
}
}
void AddMethod(const GlobalDecl GD, bool MorallyVirtual, Index_t Offset,
int64_t CurrentVBaseOffset) {
// If we can find a previously allocated slot for this, reuse it.
if (OverrideMethod(GD, MorallyVirtual, Offset, Offset,
CurrentVBaseOffset))
return;
D1(printf(" vfn for %s at %d\n",
dyn_cast<CXXMethodDecl>(GD.getDecl())->getNameAsString().c_str(),
(int)Methods.size()));
// We didn't find an entry in the vtable that we could use, add a new
// entry.
Methods.AddMethod(GD);
VCallOffset[GD] = Offset/8 - CurrentVBaseOffset/8;
if (MorallyVirtual) {
GlobalDecl UGD = getUnique(GD);
const CXXMethodDecl *UMD = cast<CXXMethodDecl>(UGD.getDecl());
assert(UMD && "final overrider not found");
Index_t &idx = VCall[UMD];
// Allocate the first one, after that, we reuse the previous one.
if (idx == 0) {
VCallOffsetForVCall[UGD] = Offset/8;
NonVirtualOffset[UMD] = Offset/8 - CurrentVBaseOffset/8;
idx = VCalls.size()+1;
VCalls.push_back(Offset/8 - CurrentVBaseOffset/8);
D1(printf(" vcall for %s at %d with delta %d\n",
dyn_cast<CXXMethodDecl>(GD.getDecl())->getNameAsString().c_str(),
(int)-VCalls.size()-3, (int)VCalls[idx-1]));
}
}
}
void AddMethods(const CXXRecordDecl *RD, bool MorallyVirtual,
Index_t Offset, int64_t CurrentVBaseOffset) {
for (method_iter mi = RD->method_begin(), me = RD->method_end(); mi != me;
++mi) {
const CXXMethodDecl *MD = *mi;
if (!MD->isVirtual())
continue;
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
// For destructors, add both the complete and the deleting destructor
// to the vtable.
AddMethod(GlobalDecl(DD, Dtor_Complete), MorallyVirtual, Offset,
CurrentVBaseOffset);
AddMethod(GlobalDecl(DD, Dtor_Deleting), MorallyVirtual, Offset,
CurrentVBaseOffset);
} else
AddMethod(MD, MorallyVirtual, Offset, CurrentVBaseOffset);
}
}
void NonVirtualBases(const CXXRecordDecl *RD, const ASTRecordLayout &Layout,
const CXXRecordDecl *PrimaryBase,
bool PrimaryBaseWasVirtual, bool MorallyVirtual,
int64_t Offset, int64_t CurrentVBaseOffset,
Path_t *Path) {
Path->push_back(std::make_pair(RD, Offset));
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
if (i->isVirtual())
continue;
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
uint64_t o = Offset + Layout.getBaseClassOffset(Base);
StartNewTable();
GenerateVtableForBase(Base, o, MorallyVirtual, false,
true, Base == PrimaryBase && !PrimaryBaseWasVirtual,
CurrentVBaseOffset, Path);
}
Path->pop_back();
}
// #define D(X) do { X; } while (0)
#define D(X)
void insertVCalls(int InsertionPoint) {
D1(printf("============= combining vbase/vcall\n"));
D(VCalls.insert(VCalls.begin(), 673));
D(VCalls.push_back(672));
VtableComponents.insert(VtableComponents.begin() + InsertionPoint,
VCalls.size(), 0);
if (BuildVtable) {
// The vcalls come first...
for (std::vector<Index_t>::reverse_iterator i = VCalls.rbegin(),
e = VCalls.rend();
i != e; ++i)
VtableComponents[InsertionPoint++] = wrap((0?600:0) + *i);
}
VCalls.clear();
VCall.clear();
VCallOffsetForVCall.clear();
VCallOffset.clear();
NonVirtualOffset.clear();
}
void AddAddressPoints(const CXXRecordDecl *RD, uint64_t Offset,
Index_t AddressPoint) {
D1(printf("XXX address point for %s in %s layout %s at offset %d is %d\n",
RD->getNameAsCString(), MostDerivedClass->getNameAsCString(),
LayoutClass->getNameAsCString(), (int)Offset, (int)AddressPoint));
subAddressPoints[std::make_pair(RD, Offset)] = AddressPoint;
AddressPoints[BaseSubobject(RD, Offset)] = AddressPoint;
// Now also add the address point for all our primary bases.
while (1) {
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
RD = Layout.getPrimaryBase();
const bool PrimaryBaseWasVirtual = Layout.getPrimaryBaseWasVirtual();
// FIXME: Double check this.
if (RD == 0)
break;
if (PrimaryBaseWasVirtual &&
BLayout.getVBaseClassOffset(RD) != Offset)
break;
D1(printf("XXX address point for %s in %s layout %s at offset %d is %d\n",
RD->getNameAsCString(), MostDerivedClass->getNameAsCString(),
LayoutClass->getNameAsCString(), (int)Offset, (int)AddressPoint));
subAddressPoints[std::make_pair(RD, Offset)] = AddressPoint;
AddressPoints[BaseSubobject(RD, Offset)] = AddressPoint;
}
}
void FinishGenerateVtable(const CXXRecordDecl *RD,
const ASTRecordLayout &Layout,
const CXXRecordDecl *PrimaryBase,
bool ForNPNVBases, bool WasPrimaryBase,
bool PrimaryBaseWasVirtual,
bool MorallyVirtual, int64_t Offset,
bool ForVirtualBase, int64_t CurrentVBaseOffset,
Path_t *Path) {
bool alloc = false;
if (Path == 0) {
alloc = true;
Path = new Path_t;
}
StartNewTable();
extra = 0;
Index_t AddressPoint = 0;
int VCallInsertionPoint = 0;
if (!ForNPNVBases || !WasPrimaryBase) {
bool DeferVCalls = MorallyVirtual || ForVirtualBase;
VCallInsertionPoint = VtableComponents.size();
if (!DeferVCalls) {
insertVCalls(VCallInsertionPoint);
} else
// FIXME: just for extra, or for all uses of VCalls.size post this?
extra = -VCalls.size();
// Add the offset to top.
VtableComponents.push_back(BuildVtable ? wrap(-((Offset-LayoutOffset)/8)) : 0);
// Add the RTTI information.
VtableComponents.push_back(rtti);
AddressPoint = VtableComponents.size();
AppendMethodsToVtable();
}
// and then the non-virtual bases.
NonVirtualBases(RD, Layout, PrimaryBase, PrimaryBaseWasVirtual,
MorallyVirtual, Offset, CurrentVBaseOffset, Path);
if (ForVirtualBase) {
// FIXME: We're adding to VCalls in callers, we need to do the overrides
// in the inner part, so that we know the complete set of vcalls during
// the build and don't have to insert into methods. Saving out the
// AddressPoint here, would need to be fixed, if we didn't do that. Also
// retroactively adding vcalls for overrides later wind up in the wrong
// place, the vcall slot has to be alloted during the walk of the base
// when the function is first introduces.
AddressPoint += VCalls.size();
insertVCalls(VCallInsertionPoint);
}
if (!ForNPNVBases || !WasPrimaryBase)
AddAddressPoints(RD, Offset, AddressPoint);
if (alloc) {
delete Path;
}
}
void Primaries(const CXXRecordDecl *RD, bool MorallyVirtual, int64_t Offset,
bool updateVBIndex, Index_t current_vbindex,
int64_t CurrentVBaseOffset) {
if (!RD->isDynamicClass())
return;
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
const bool PrimaryBaseWasVirtual = Layout.getPrimaryBaseWasVirtual();
// vtables are composed from the chain of primaries.
if (PrimaryBase && !PrimaryBaseWasVirtual) {
D1(printf(" doing primaries for %s most derived %s\n",
RD->getNameAsCString(), MostDerivedClass->getNameAsCString()));
Primaries(PrimaryBase, PrimaryBaseWasVirtual|MorallyVirtual, Offset,
updateVBIndex, current_vbindex, CurrentVBaseOffset);
}
D1(printf(" doing vcall entries for %s most derived %s\n",
RD->getNameAsCString(), MostDerivedClass->getNameAsCString()));
// And add the virtuals for the class to the primary vtable.
AddMethods(RD, MorallyVirtual, Offset, CurrentVBaseOffset);
}
void VBPrimaries(const CXXRecordDecl *RD, bool MorallyVirtual, int64_t Offset,
bool updateVBIndex, Index_t current_vbindex,
bool RDisVirtualBase, int64_t CurrentVBaseOffset,
bool bottom) {
if (!RD->isDynamicClass())
return;
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
const bool PrimaryBaseWasVirtual = Layout.getPrimaryBaseWasVirtual();
// vtables are composed from the chain of primaries.
if (PrimaryBase) {
int BaseCurrentVBaseOffset = CurrentVBaseOffset;
if (PrimaryBaseWasVirtual) {
IndirectPrimary.insert(PrimaryBase);
BaseCurrentVBaseOffset = BLayout.getVBaseClassOffset(PrimaryBase);
}
D1(printf(" doing primaries for %s most derived %s\n",
RD->getNameAsCString(), MostDerivedClass->getNameAsCString()));
VBPrimaries(PrimaryBase, PrimaryBaseWasVirtual|MorallyVirtual, Offset,
updateVBIndex, current_vbindex, PrimaryBaseWasVirtual,
BaseCurrentVBaseOffset, false);
}
D1(printf(" doing vbase entries for %s most derived %s\n",
RD->getNameAsCString(), MostDerivedClass->getNameAsCString()));
GenerateVBaseOffsets(RD, Offset, updateVBIndex, current_vbindex);
if (RDisVirtualBase || bottom) {
Primaries(RD, MorallyVirtual, Offset, updateVBIndex, current_vbindex,
CurrentVBaseOffset);
}
}
void GenerateVtableForBase(const CXXRecordDecl *RD, int64_t Offset = 0,
bool MorallyVirtual = false,
bool ForVirtualBase = false,
bool ForNPNVBases = false,
bool WasPrimaryBase = true,
int CurrentVBaseOffset = 0,
Path_t *Path = 0) {
if (!RD->isDynamicClass())
return;
// Construction vtable don't need parts that have no virtual bases and
// aren't morally virtual.
if ((LayoutClass != MostDerivedClass) &&
RD->getNumVBases() == 0 && !MorallyVirtual)
return;
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
const bool PrimaryBaseWasVirtual = Layout.getPrimaryBaseWasVirtual();
extra = 0;
D1(printf("building entries for base %s most derived %s\n",
RD->getNameAsCString(), MostDerivedClass->getNameAsCString()));
if (ForVirtualBase)
extra = VCalls.size();
if (!ForNPNVBases || !WasPrimaryBase) {
VBPrimaries(RD, MorallyVirtual, Offset, !ForVirtualBase, 0,
ForVirtualBase, CurrentVBaseOffset, true);
if (Path)
OverrideMethods(Path, MorallyVirtual, Offset, CurrentVBaseOffset);
}
FinishGenerateVtable(RD, Layout, PrimaryBase, ForNPNVBases, WasPrimaryBase,
PrimaryBaseWasVirtual, MorallyVirtual, Offset,
ForVirtualBase, CurrentVBaseOffset, Path);
}
void GenerateVtableForVBases(const CXXRecordDecl *RD,
int64_t Offset = 0,
Path_t *Path = 0) {
bool alloc = false;
if (Path == 0) {
alloc = true;
Path = new Path_t;
}
// FIXME: We also need to override using all paths to a virtual base,
// right now, we just process the first path
Path->push_back(std::make_pair(RD, Offset));
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
if (i->isVirtual() && !IndirectPrimary.count(Base)) {
// Mark it so we don't output it twice.
IndirectPrimary.insert(Base);
StartNewTable();
VCall.clear();
int64_t BaseOffset = BLayout.getVBaseClassOffset(Base);
int64_t CurrentVBaseOffset = BaseOffset;
D1(printf("vtable %s virtual base %s\n",
MostDerivedClass->getNameAsCString(), Base->getNameAsCString()));
GenerateVtableForBase(Base, BaseOffset, true, true, false,
true, CurrentVBaseOffset, Path);
}
int64_t BaseOffset;
if (i->isVirtual())
BaseOffset = BLayout.getVBaseClassOffset(Base);
else {
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
BaseOffset = Offset + Layout.getBaseClassOffset(Base);
}
if (Base->getNumVBases()) {
GenerateVtableForVBases(Base, BaseOffset, Path);
}
}
Path->pop_back();
if (alloc)
delete Path;
}
};
} // end anonymous namespace
bool OldVtableBuilder::OverrideMethod(GlobalDecl GD, bool MorallyVirtual,
Index_t OverrideOffset, Index_t Offset,
int64_t CurrentVBaseOffset) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
const bool isPure = MD->isPure();
// FIXME: Should OverrideOffset's be Offset?
for (CXXMethodDecl::method_iterator mi = MD->begin_overridden_methods(),
e = MD->end_overridden_methods(); mi != e; ++mi) {
GlobalDecl OGD;
GlobalDecl OGD2;
const CXXMethodDecl *OMD = *mi;
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(OMD))
OGD = GlobalDecl(DD, GD.getDtorType());
else
OGD = OMD;
// Check whether this is the method being overridden in this section of
// the vtable.
uint64_t Index;
if (!Methods.getIndex(OGD, Index))
continue;
OGD2 = OGD;
// Get the original method, which we should be computing thunks, etc,
// against.
OGD = Methods.getOrigMethod(Index);
OMD = cast<CXXMethodDecl>(OGD.getDecl());
QualType ReturnType =
MD->getType()->getAs<FunctionType>()->getResultType();
QualType OverriddenReturnType =
OMD->getType()->getAs<FunctionType>()->getResultType();
// Check if we need a return type adjustment.
if (!ComputeReturnAdjustmentBaseOffset(CGM.getContext(), MD,
OMD).isEmpty()) {
CanQualType &BaseReturnType = BaseReturnTypes[Index];
// Insert the base return type.
if (BaseReturnType.isNull())
BaseReturnType =
CGM.getContext().getCanonicalType(OverriddenReturnType);
}
Methods.OverrideMethod(OGD, GD);
GlobalDecl UGD = getUnique(GD);
const CXXMethodDecl *UMD = cast<CXXMethodDecl>(UGD.getDecl());
assert(UGD.getDecl() && "unique overrider not found");
assert(UGD == getUnique(OGD) && "unique overrider not unique");
ThisAdjustments.erase(Index);
if (MorallyVirtual || VCall.count(UMD)) {
Index_t &idx = VCall[UMD];
if (idx == 0) {
VCallOffset[GD] = VCallOffset[OGD];
// NonVirtualOffset[UMD] = CurrentVBaseOffset/8 - OverrideOffset/8;
NonVirtualOffset[UMD] = VCallOffset[OGD];
VCallOffsetForVCall[UMD] = OverrideOffset/8;
idx = VCalls.size()+1;
VCalls.push_back(OverrideOffset/8 - CurrentVBaseOffset/8);
D1(printf(" vcall for %s at %d with delta %d most derived %s\n",
MD->getNameAsString().c_str(), (int)-idx-3,
(int)VCalls[idx-1], MostDerivedClass->getNameAsCString()));
} else {
VCallOffset[GD] = NonVirtualOffset[UMD];
VCalls[idx-1] = -VCallOffsetForVCall[UGD] + OverrideOffset/8;
D1(printf(" vcall patch for %s at %d with delta %d most derived %s\n",
MD->getNameAsString().c_str(), (int)-idx-3,
(int)VCalls[idx-1], MostDerivedClass->getNameAsCString()));
}
int64_t NonVirtualAdjustment = -VCallOffset[OGD];
QualType DerivedType = MD->getThisType(CGM.getContext());
QualType BaseType = cast<const CXXMethodDecl>(OGD.getDecl())->getThisType(CGM.getContext());
int64_t NonVirtualAdjustment2 = -(getNVOffset(BaseType, DerivedType)/8);
if (NonVirtualAdjustment2 != NonVirtualAdjustment) {
NonVirtualAdjustment = NonVirtualAdjustment2;
}
int64_t VirtualAdjustment =
-((idx + extra + 2) * LLVMPointerWidth / 8);
// Optimize out virtual adjustments of 0.
if (VCalls[idx-1] == 0)
VirtualAdjustment = 0;
ThunkAdjustment ThisAdjustment(NonVirtualAdjustment,
VirtualAdjustment);
if (!isPure && !ThisAdjustment.isEmpty()) {
ThisAdjustments[Index] = ThisAdjustment;
SavedAdjustments.push_back(
std::make_pair(GD, std::make_pair(OGD, ThisAdjustment)));
}
return true;
}
VCallOffset[GD] = VCallOffset[OGD2] - OverrideOffset/8;
int64_t NonVirtualAdjustment = -VCallOffset[GD];
QualType DerivedType = MD->getThisType(CGM.getContext());
QualType BaseType = cast<const CXXMethodDecl>(OGD.getDecl())->getThisType(CGM.getContext());
int64_t NonVirtualAdjustment2 = -(getNVOffset(BaseType, DerivedType)/8);
if (NonVirtualAdjustment2 != NonVirtualAdjustment) {
NonVirtualAdjustment = NonVirtualAdjustment2;
}
if (NonVirtualAdjustment) {
ThunkAdjustment ThisAdjustment(NonVirtualAdjustment, 0);
if (!isPure) {
ThisAdjustments[Index] = ThisAdjustment;
SavedAdjustments.push_back(
std::make_pair(GD, std::make_pair(OGD, ThisAdjustment)));
}
}
return true;
}
return false;
}
void OldVtableBuilder::AppendMethodsToVtable() {
if (!BuildVtable) {
VtableComponents.insert(VtableComponents.end(), Methods.size(),
(llvm::Constant *)0);
ThisAdjustments.clear();
BaseReturnTypes.clear();
Methods.clear();
return;
}
// Reserve room in the vtable for our new methods.
VtableComponents.reserve(VtableComponents.size() + Methods.size());
for (unsigned i = 0, e = Methods.size(); i != e; ++i) {
GlobalDecl GD = Methods[i];
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
// Get the 'this' pointer adjustment.
ThunkAdjustment ThisAdjustment = ThisAdjustments.lookup(i);
// Construct the return type adjustment.
ThunkAdjustment ReturnAdjustment;
QualType BaseReturnType = BaseReturnTypes.lookup(i);
if (!BaseReturnType.isNull() && !MD->isPure()) {
QualType DerivedType =
MD->getType()->getAs<FunctionType>()->getResultType();
int64_t NonVirtualAdjustment =
getNVOffset(BaseReturnType, DerivedType) / 8;
int64_t VirtualAdjustment =
getVbaseOffset(BaseReturnType, DerivedType);
ReturnAdjustment = ThunkAdjustment(NonVirtualAdjustment,
VirtualAdjustment);
}
llvm::Constant *Method = 0;
if (!ReturnAdjustment.isEmpty()) {
// Build a covariant thunk.
CovariantThunkAdjustment Adjustment(ThisAdjustment, ReturnAdjustment);
Method = wrap(CGM.GetAddrOfCovariantThunk(GD, Adjustment));
} else if (!ThisAdjustment.isEmpty()) {
// Build a "regular" thunk.
Method = wrap(CGM.GetAddrOfThunk(GD, ThisAdjustment));
} else if (MD->isPure()) {
// We have a pure virtual method.
Method = getPureVirtualFn();
} else {
// We have a good old regular method.
Method = WrapAddrOf(GD);
}
// Add the method to the vtable.
VtableComponents.push_back(Method);
}
ThisAdjustments.clear();
BaseReturnTypes.clear();
Methods.clear();
}
void CGVtableInfo::ComputeMethodVtableIndices(const CXXRecordDecl *RD) {
// Itanium C++ ABI 2.5.2:
// The order of the virtual function pointers in a virtual table is the
// order of declaration of the corresponding member functions in the class.
//
// There is an entry for any virtual function declared in a class,
// whether it is a new function or overrides a base class function,
// unless it overrides a function from the primary base, and conversion
// between their return types does not require an adjustment.
int64_t CurrentIndex = 0;
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
if (PrimaryBase) {
assert(PrimaryBase->isDefinition() &&
"Should have the definition decl of the primary base!");
// Since the record decl shares its vtable pointer with the primary base
// we need to start counting at the end of the primary base's vtable.
CurrentIndex = getNumVirtualFunctionPointers(PrimaryBase);
}
// Collect all the primary bases, so we can check whether methods override
// a method from the base.
VtableBuilder::PrimaryBasesSetTy PrimaryBases;
for (ASTRecordLayout::primary_base_info_iterator
I = Layout.primary_base_begin(), E = Layout.primary_base_end();
I != E; ++I)
PrimaryBases.insert((*I).getBase());
const CXXDestructorDecl *ImplicitVirtualDtor = 0;
for (CXXRecordDecl::method_iterator i = RD->method_begin(),
e = RD->method_end(); i != e; ++i) {
const CXXMethodDecl *MD = *i;
// We only want virtual methods.
if (!MD->isVirtual())
continue;
// Check if this method overrides a method in the primary base.
if (const CXXMethodDecl *OverriddenMD =
OverridesMethodInPrimaryBase(MD, PrimaryBases)) {
// Check if converting from the return type of the method to the
// return type of the overridden method requires conversion.
if (ComputeReturnAdjustmentBaseOffset(CGM.getContext(), MD,
OverriddenMD).isEmpty()) {
// This index is shared between the index in the vtable of the primary
// base class.
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
const CXXDestructorDecl *OverriddenDD =
cast<CXXDestructorDecl>(OverriddenMD);
// Add both the complete and deleting entries.
MethodVtableIndices[GlobalDecl(DD, Dtor_Complete)] =
getMethodVtableIndex(GlobalDecl(OverriddenDD, Dtor_Complete));
MethodVtableIndices[GlobalDecl(DD, Dtor_Deleting)] =
getMethodVtableIndex(GlobalDecl(OverriddenDD, Dtor_Deleting));
} else {
MethodVtableIndices[MD] = getMethodVtableIndex(OverriddenMD);
}
// We don't need to add an entry for this method.
continue;
}
}
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
if (MD->isImplicit()) {
assert(!ImplicitVirtualDtor &&
"Did already see an implicit virtual dtor!");
ImplicitVirtualDtor = DD;
continue;
}
// Add the complete dtor.
MethodVtableIndices[GlobalDecl(DD, Dtor_Complete)] = CurrentIndex++;
// Add the deleting dtor.
MethodVtableIndices[GlobalDecl(DD, Dtor_Deleting)] = CurrentIndex++;
} else {
// Add the entry.
MethodVtableIndices[MD] = CurrentIndex++;
}
}
if (ImplicitVirtualDtor) {
// Itanium C++ ABI 2.5.2:
// If a class has an implicitly-defined virtual destructor,
// its entries come after the declared virtual function pointers.
// Add the complete dtor.
MethodVtableIndices[GlobalDecl(ImplicitVirtualDtor, Dtor_Complete)] =
CurrentIndex++;
// Add the deleting dtor.
MethodVtableIndices[GlobalDecl(ImplicitVirtualDtor, Dtor_Deleting)] =
CurrentIndex++;
}
NumVirtualFunctionPointers[RD] = CurrentIndex;
}
uint64_t CGVtableInfo::getNumVirtualFunctionPointers(const CXXRecordDecl *RD) {
llvm::DenseMap<const CXXRecordDecl *, uint64_t>::iterator I =
NumVirtualFunctionPointers.find(RD);
if (I != NumVirtualFunctionPointers.end())
return I->second;
ComputeMethodVtableIndices(RD);
I = NumVirtualFunctionPointers.find(RD);
assert(I != NumVirtualFunctionPointers.end() && "Did not find entry!");
return I->second;
}
uint64_t CGVtableInfo::getMethodVtableIndex(GlobalDecl GD) {
MethodVtableIndicesTy::iterator I = MethodVtableIndices.find(GD);
if (I != MethodVtableIndices.end())
return I->second;
const CXXRecordDecl *RD = cast<CXXMethodDecl>(GD.getDecl())->getParent();
ComputeMethodVtableIndices(RD);
I = MethodVtableIndices.find(GD);
assert(I != MethodVtableIndices.end() && "Did not find index!");
return I->second;
}
CGVtableInfo::AdjustmentVectorTy*
CGVtableInfo::getAdjustments(GlobalDecl GD) {
SavedAdjustmentsTy::iterator I = SavedAdjustments.find(GD);
if (I != SavedAdjustments.end())
return &I->second;
const CXXRecordDecl *RD = cast<CXXRecordDecl>(GD.getDecl()->getDeclContext());
if (!SavedAdjustmentRecords.insert(RD).second)
return 0;
AddressPointsMapTy AddressPoints;
OldVtableBuilder b(RD, RD, 0, CGM, false, AddressPoints);
D1(printf("vtable %s\n", RD->getNameAsCString()));
b.GenerateVtableForBase(RD);
b.GenerateVtableForVBases(RD);
for (OldVtableBuilder::SavedAdjustmentsVectorTy::iterator
i = b.getSavedAdjustments().begin(),
e = b.getSavedAdjustments().end(); i != e; i++)
SavedAdjustments[i->first].push_back(i->second);
I = SavedAdjustments.find(GD);
if (I != SavedAdjustments.end())
return &I->second;
return 0;
}
int64_t CGVtableInfo::getVirtualBaseOffsetIndex(const CXXRecordDecl *RD,
const CXXRecordDecl *VBase) {
ClassPairTy ClassPair(RD, VBase);
VirtualBaseClassIndiciesTy::iterator I =
VirtualBaseClassIndicies.find(ClassPair);
if (I != VirtualBaseClassIndicies.end())
return I->second;
// FIXME: This seems expensive. Can we do a partial job to get
// just this data.
AddressPointsMapTy AddressPoints;
OldVtableBuilder b(RD, RD, 0, CGM, false, AddressPoints);
D1(printf("vtable %s\n", RD->getNameAsCString()));
b.GenerateVtableForBase(RD);
b.GenerateVtableForVBases(RD);
for (llvm::DenseMap<const CXXRecordDecl *, uint64_t>::iterator I =
b.getVBIndex().begin(), E = b.getVBIndex().end(); I != E; ++I) {
// Insert all types.
ClassPairTy ClassPair(RD, I->first);
VirtualBaseClassIndicies.insert(std::make_pair(ClassPair, I->second));
}
I = VirtualBaseClassIndicies.find(ClassPair);
// FIXME: The assertion below assertion currently fails with the old vtable
/// layout code if there is a non-virtual thunk adjustment in a vtable.
// Once the new layout is in place, this return should be removed.
if (I == VirtualBaseClassIndicies.end())
return 0;
assert(I != VirtualBaseClassIndicies.end() && "Did not find index!");
return I->second;
}
uint64_t CGVtableInfo::getVtableAddressPoint(const CXXRecordDecl *RD) {
uint64_t AddressPoint =
(*(*(CGM.getVtableInfo().AddressPoints[RD]))[RD])[std::make_pair(RD, 0)];
return AddressPoint;
}
llvm::GlobalVariable *
CGVtableInfo::GenerateVtable(llvm::GlobalVariable::LinkageTypes Linkage,
bool GenerateDefinition,
const CXXRecordDecl *LayoutClass,
const CXXRecordDecl *RD, uint64_t Offset,
AddressPointsMapTy& AddressPoints) {
if (GenerateDefinition && CGM.getLangOptions().DumpVtableLayouts &&
LayoutClass == RD) {
VtableBuilder Builder(*this, RD);
Builder.dumpLayout(llvm::errs());
}
llvm::SmallString<256> OutName;
if (LayoutClass != RD)
CGM.getMangleContext().mangleCXXCtorVtable(LayoutClass, Offset / 8,
RD, OutName);
else
CGM.getMangleContext().mangleCXXVtable(RD, OutName);
llvm::StringRef Name = OutName.str();
llvm::GlobalVariable *GV = CGM.getModule().getGlobalVariable(Name);
if (GV == 0 || CGM.getVtableInfo().AddressPoints[LayoutClass] == 0 ||
GV->isDeclaration()) {
OldVtableBuilder b(RD, LayoutClass, Offset, CGM, GenerateDefinition,
AddressPoints);
D1(printf("vtable %s\n", RD->getNameAsCString()));
// First comes the vtables for all the non-virtual bases...
b.GenerateVtableForBase(RD, Offset);
// then the vtables for all the virtual bases.
b.GenerateVtableForVBases(RD, Offset);
llvm::Constant *Init = 0;
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGM.getLLVMContext());
llvm::ArrayType *ArrayType =
llvm::ArrayType::get(Int8PtrTy, b.getVtableComponents().size());
if (GenerateDefinition)
Init = llvm::ConstantArray::get(ArrayType, &b.getVtableComponents()[0],
b.getVtableComponents().size());
llvm::GlobalVariable *OGV = GV;
GV = new llvm::GlobalVariable(CGM.getModule(), ArrayType,
/*isConstant=*/true, Linkage, Init, Name);
CGM.setGlobalVisibility(GV, RD);
if (OGV) {
GV->takeName(OGV);
llvm::Constant *NewPtr =
llvm::ConstantExpr::getBitCast(GV, OGV->getType());
OGV->replaceAllUsesWith(NewPtr);
OGV->eraseFromParent();
}
}
return GV;
}
void CGVtableInfo::GenerateClassData(llvm::GlobalVariable::LinkageTypes Linkage,
const CXXRecordDecl *RD) {
llvm::GlobalVariable *&Vtable = Vtables[RD];
if (Vtable) {
assert(Vtable->getInitializer() && "Vtable doesn't have a definition!");
return;
}
AddressPointsMapTy AddressPoints;
Vtable = GenerateVtable(Linkage, /*GenerateDefinition=*/true, RD, RD, 0,
AddressPoints);
GenerateVTT(Linkage, /*GenerateDefinition=*/true, RD);
}
llvm::GlobalVariable *CGVtableInfo::getVtable(const CXXRecordDecl *RD) {
llvm::GlobalVariable *Vtable = Vtables.lookup(RD);
if (!Vtable) {
AddressPointsMapTy AddressPoints;
Vtable = GenerateVtable(llvm::GlobalValue::ExternalLinkage,
/*GenerateDefinition=*/false, RD, RD, 0,
AddressPoints);
}
return Vtable;
}
void CGVtableInfo::MaybeEmitVtable(GlobalDecl GD) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
const CXXRecordDecl *RD = MD->getParent();
// If the class doesn't have a vtable we don't need to emit one.
if (!RD->isDynamicClass())
return;
// Get the key function.
const CXXMethodDecl *KeyFunction = CGM.getContext().getKeyFunction(RD);
if (KeyFunction) {
// We don't have the right key function.
if (KeyFunction->getCanonicalDecl() != MD->getCanonicalDecl())
return;
}
// Emit the data.
GenerateClassData(CGM.getVtableLinkage(RD), RD);
for (CXXRecordDecl::method_iterator i = RD->method_begin(),
e = RD->method_end(); i != e; ++i) {
if ((*i)->isVirtual() && ((*i)->hasInlineBody() || (*i)->isImplicit())) {
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(*i)) {
CGM.BuildThunksForVirtual(GlobalDecl(DD, Dtor_Complete));
CGM.BuildThunksForVirtual(GlobalDecl(DD, Dtor_Deleting));
} else {
CGM.BuildThunksForVirtual(GlobalDecl(*i));
}
}
}
}
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