replica
/
hanchenye-llvm-project
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Move VTT builder to AST 

llvm-svn: 140501
This commit is contained in:
Peter Collingbourne 2011-09-26 01:56:24 +00:00
parent 66c3a83e09
commit 2d2595235d
4 changed files with 390 additions and 337 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

176
clang/include/clang/AST/VTTBuilder.h Normal file
View File

@ -0,0 +1,176 @@
//===--- VTTBuilder.h - C++ VTT layout builder --------------------*- C++ -*-=//
//
// 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 generation of the layout of virtual table
// tables (VTT).
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_AST_VTTBUILDER_H
#define LLVM_CLANG_AST_VTTBUILDER_H
#include "clang/AST/BaseSubobject.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/GlobalDecl.h"
#include "clang/AST/RecordLayout.h"
#include "clang/Basic/ABI.h"
#include "llvm/ADT/SetVector.h"
#include <utility>
namespace clang {
class VTTVTable {
llvm::PointerIntPair<const CXXRecordDecl *, 1, bool> BaseAndIsVirtual;
CharUnits BaseOffset;
public:
VTTVTable() {}
VTTVTable(const CXXRecordDecl *Base, CharUnits BaseOffset, bool BaseIsVirtual)
: BaseAndIsVirtual(Base, BaseIsVirtual), BaseOffset(BaseOffset) {}
VTTVTable(BaseSubobject Base, bool BaseIsVirtual)
: BaseAndIsVirtual(Base.getBase(), BaseIsVirtual),
BaseOffset(Base.getBaseOffset()) {}
const CXXRecordDecl *getBase() const {
return BaseAndIsVirtual.getPointer();
}
CharUnits getBaseOffset() const {
return BaseOffset;
}
bool isVirtual() const {
return BaseAndIsVirtual.getInt();
}
BaseSubobject getBaseSubobject() const {
return BaseSubobject(getBase(), getBaseOffset());
}
};
struct VTTComponent {
uint64_t VTableIndex;
BaseSubobject VTableBase;
VTTComponent() {}
VTTComponent(uint64_t VTableIndex, BaseSubobject VTableBase)
: VTableIndex(VTableIndex), VTableBase(VTableBase) {}
};
/// VTT builder - Class for building VTT layout information.
class VTTBuilder {
ASTContext &Ctx;
/// MostDerivedClass - The most derived class for which we're building this
/// vtable.
const CXXRecordDecl *MostDerivedClass;
typedef SmallVector<VTTVTable, 64> VTTVTablesVectorTy;
/// VTTVTables - The VTT vtables.
VTTVTablesVectorTy VTTVTables;
typedef SmallVector<VTTComponent, 64> VTTComponentsVectorTy;
/// VTTComponents - The VTT components.
VTTComponentsVectorTy VTTComponents;
/// MostDerivedClassLayout - the AST record layout of the most derived class.
const ASTRecordLayout &MostDerivedClassLayout;
typedef llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBasesSetTy;
typedef llvm::DenseMap<BaseSubobject, uint64_t> AddressPointsMapTy;
/// SubVTTIndicies - The sub-VTT indices for the bases of the most derived
/// class.
llvm::DenseMap<BaseSubobject, uint64_t> SubVTTIndicies;
/// SecondaryVirtualPointerIndices - The secondary virtual pointer indices of
/// all subobjects of the most derived class.
llvm::DenseMap<BaseSubobject, uint64_t> SecondaryVirtualPointerIndices;
/// GenerateDefinition - Whether the VTT builder should generate LLVM IR for
/// the VTT.
bool GenerateDefinition;
/// AddVTablePointer - Add a vtable pointer to the VTT currently being built.
///
/// \param AddressPoints - If the vtable is a construction vtable, this has
/// the address points for it.
void AddVTablePointer(BaseSubobject Base, uint64_t VTableIndex,
const CXXRecordDecl *VTableClass);
/// LayoutSecondaryVTTs - Lay out the secondary VTTs of the given base
/// subobject.
void LayoutSecondaryVTTs(BaseSubobject Base);
/// LayoutSecondaryVirtualPointers - Lay out the secondary virtual pointers
/// for the given base subobject.
///
/// \param BaseIsMorallyVirtual whether the base subobject is a virtual base
/// or a direct or indirect base of a virtual base.
///
/// \param AddressPoints - If the vtable is a construction vtable, this has
/// the address points for it.
void LayoutSecondaryVirtualPointers(BaseSubobject Base,
bool BaseIsMorallyVirtual,
uint64_t VTableIndex,
const CXXRecordDecl *VTableClass,
VisitedVirtualBasesSetTy &VBases);
/// LayoutSecondaryVirtualPointers - Lay out the secondary virtual pointers
/// for the given base subobject.
///
/// \param AddressPoints - If the vtable is a construction vtable, this has
/// the address points for it.
void LayoutSecondaryVirtualPointers(BaseSubobject Base,
uint64_t VTableIndex);
/// LayoutVirtualVTTs - Lay out the VTTs for the virtual base classes of the
/// given record decl.
void LayoutVirtualVTTs(const CXXRecordDecl *RD,
VisitedVirtualBasesSetTy &VBases);
/// LayoutVTT - Will lay out the VTT for the given subobject, including any
/// secondary VTTs, secondary virtual pointers and virtual VTTs.
void LayoutVTT(BaseSubobject Base, bool BaseIsVirtual);
public:
VTTBuilder(ASTContext &Ctx, const CXXRecordDecl *MostDerivedClass,
bool GenerateDefinition);
// getVTTComponents - Returns a reference to the VTT components.
const VTTComponentsVectorTy &getVTTComponents() const {
return VTTComponents;
}
// getVTTVTables - Returns a reference to the VTT vtables.
const VTTVTablesVectorTy &getVTTVTables() const {
return VTTVTables;
}
/// getSubVTTIndicies - Returns a reference to the sub-VTT indices.
const llvm::DenseMap<BaseSubobject, uint64_t> &getSubVTTIndicies() const {
return SubVTTIndicies;
}
/// getSecondaryVirtualPointerIndices - Returns a reference to the secondary
/// virtual pointer indices.
const llvm::DenseMap<BaseSubobject, uint64_t> &
getSecondaryVirtualPointerIndices() const {
return SecondaryVirtualPointerIndices;
}
};
}
#endif

1
clang/lib/AST/CMakeLists.txt
View File

@ -46,6 +46,7 @@ add_clang_library(clangAST
Type.cpp
TypeLoc.cpp
TypePrinter.cpp
VTTBuilder.cpp
)
add_dependencies(clangAST ClangARMNeon ClangAttrClasses ClangAttrList

212
clang/lib/AST/VTTBuilder.cpp Normal file
View File

@ -0,0 +1,212 @@
//===--- VTTBuilder.cpp - C++ VTT layout builder --------------------------===//
//
// 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 generation of the layout of virtual table
// tables (VTT).
//
//===----------------------------------------------------------------------===//
#include "clang/AST/VTTBuilder.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/RecordLayout.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/Support/Format.h"
#include <algorithm>
#include <cstdio>
using namespace clang;
#define DUMP_OVERRIDERS 0
VTTBuilder::VTTBuilder(ASTContext &Ctx,
const CXXRecordDecl *MostDerivedClass,
bool GenerateDefinition)
: Ctx(Ctx), MostDerivedClass(MostDerivedClass),
MostDerivedClassLayout(Ctx.getASTRecordLayout(MostDerivedClass)),
GenerateDefinition(GenerateDefinition) {
// Lay out this VTT.
LayoutVTT(BaseSubobject(MostDerivedClass, CharUnits::Zero()),
/*BaseIsVirtual=*/false);
}
void VTTBuilder::AddVTablePointer(BaseSubobject Base, uint64_t VTableIndex,
const CXXRecordDecl *VTableClass) {
// Store the vtable pointer index if we're generating the primary VTT.
if (VTableClass == MostDerivedClass) {
assert(!SecondaryVirtualPointerIndices.count(Base) &&
"A virtual pointer index already exists for this base subobject!");
SecondaryVirtualPointerIndices[Base] = VTTComponents.size();
}
if (!GenerateDefinition) {
VTTComponents.push_back(VTTComponent());
return;
}
VTTComponents.push_back(VTTComponent(VTableIndex, Base));
}
void VTTBuilder::LayoutSecondaryVTTs(BaseSubobject Base) {
const CXXRecordDecl *RD = Base.getBase();
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
// Don't layout virtual bases.
if (I->isVirtual())
continue;
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
CharUnits BaseOffset = Base.getBaseOffset() +
Layout.getBaseClassOffset(BaseDecl);
// Layout the VTT for this base.
LayoutVTT(BaseSubobject(BaseDecl, BaseOffset), /*BaseIsVirtual=*/false);
}
}
void
VTTBuilder::LayoutSecondaryVirtualPointers(BaseSubobject Base,
bool BaseIsMorallyVirtual,
uint64_t VTableIndex,
const CXXRecordDecl *VTableClass,
VisitedVirtualBasesSetTy &VBases) {
const CXXRecordDecl *RD = Base.getBase();
// We're not interested in bases that don't have virtual bases, and not
// morally virtual bases.
if (!RD->getNumVBases() && !BaseIsMorallyVirtual)
return;
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());
// Itanium C++ ABI 2.6.2:
// Secondary virtual pointers are present for all bases with either
// virtual bases or virtual function declarations overridden along a
// virtual path.
//
// If the base class is not dynamic, we don't want to add it, nor any
// of its base classes.
if (!BaseDecl->isDynamicClass())
continue;
bool BaseDeclIsMorallyVirtual = BaseIsMorallyVirtual;
bool BaseDeclIsNonVirtualPrimaryBase = false;
CharUnits BaseOffset;
if (I->isVirtual()) {
// Ignore virtual bases that we've already visited.
if (!VBases.insert(BaseDecl))
continue;
BaseOffset = MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
BaseDeclIsMorallyVirtual = true;
} else {
const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
BaseOffset = Base.getBaseOffset() +
Layout.getBaseClassOffset(BaseDecl);
if (!Layout.isPrimaryBaseVirtual() &&
Layout.getPrimaryBase() == BaseDecl)
BaseDeclIsNonVirtualPrimaryBase = true;
}
// Itanium C++ ABI 2.6.2:
// Secondary virtual pointers: for each base class X which (a) has virtual
// bases or is reachable along a virtual path from D, and (b) is not a
// non-virtual primary base, the address of the virtual table for X-in-D
// or an appropriate construction virtual table.
if (!BaseDeclIsNonVirtualPrimaryBase &&
(BaseDecl->getNumVBases() || BaseDeclIsMorallyVirtual)) {
// Add the vtable pointer.
AddVTablePointer(BaseSubobject(BaseDecl, BaseOffset), VTableIndex,
VTableClass);
}
// And lay out the secondary virtual pointers for the base class.
LayoutSecondaryVirtualPointers(BaseSubobject(BaseDecl, BaseOffset),
BaseDeclIsMorallyVirtual, VTableIndex,
VTableClass, VBases);
}
}
void
VTTBuilder::LayoutSecondaryVirtualPointers(BaseSubobject Base,
uint64_t VTableIndex) {
VisitedVirtualBasesSetTy VBases;
LayoutSecondaryVirtualPointers(Base, /*BaseIsMorallyVirtual=*/false,
VTableIndex, Base.getBase(), VBases);
}
void VTTBuilder::LayoutVirtualVTTs(const CXXRecordDecl *RD,
VisitedVirtualBasesSetTy &VBases) {
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.
if (I->isVirtual()) {
// Check if we've seen this base before.
if (!VBases.insert(BaseDecl))
continue;
CharUnits BaseOffset =
MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
LayoutVTT(BaseSubobject(BaseDecl, BaseOffset), /*BaseIsVirtual=*/true);
}
// We only need to layout virtual VTTs for this base if it actually has
// virtual bases.
if (BaseDecl->getNumVBases())
LayoutVirtualVTTs(BaseDecl, VBases);
}
}
void VTTBuilder::LayoutVTT(BaseSubobject Base, bool BaseIsVirtual) {
const CXXRecordDecl *RD = Base.getBase();
// Itanium C++ ABI 2.6.2:
// An array of virtual table addresses, called the VTT, is declared for
// each class type that has indirect or direct virtual base classes.
if (RD->getNumVBases() == 0)
return;
bool IsPrimaryVTT = Base.getBase() == MostDerivedClass;
if (!IsPrimaryVTT) {
// Remember the sub-VTT index.
SubVTTIndicies[Base] = VTTComponents.size();
}
uint64_t VTableIndex = VTTVTables.size();
VTTVTables.push_back(VTTVTable(Base, BaseIsVirtual));
// Add the primary vtable pointer.
AddVTablePointer(Base, VTableIndex, RD);
// Add the secondary VTTs.
LayoutSecondaryVTTs(Base);
// Add the secondary virtual pointers.
LayoutSecondaryVirtualPointers(Base, VTableIndex);
// If this is the primary VTT, we want to lay out virtual VTTs as well.
if (IsPrimaryVTT) {
VisitedVirtualBasesSetTy VBases;
LayoutVirtualVTTs(Base.getBase(), VBases);
}
}

338
clang/lib/CodeGen/CGVTT.cpp
View File

@ -14,170 +14,12 @@
#include "CodeGenModule.h"
#include "CGCXXABI.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/VTTBuilder.h"
using namespace clang;
using namespace CodeGen;
#define D1(x)
namespace {
class VTTVTable {
llvm::PointerIntPair<const CXXRecordDecl *, 1, bool> BaseAndIsVirtual;
CharUnits BaseOffset;
public:
VTTVTable() {}
VTTVTable(const CXXRecordDecl *Base, CharUnits BaseOffset, bool BaseIsVirtual)
: BaseAndIsVirtual(Base, BaseIsVirtual), BaseOffset(BaseOffset) {}
VTTVTable(BaseSubobject Base, bool BaseIsVirtual)
: BaseAndIsVirtual(Base.getBase(), BaseIsVirtual),
BaseOffset(Base.getBaseOffset()) {}
const CXXRecordDecl *getBase() const {
return BaseAndIsVirtual.getPointer();
}
CharUnits getBaseOffset() const {
return BaseOffset;
}
bool isVirtual() const {
return BaseAndIsVirtual.getInt();
}
BaseSubobject getBaseSubobject() const {
return BaseSubobject(getBase(), getBaseOffset());
}
};
struct VTTComponent {
uint64_t VTableIndex;
BaseSubobject VTableBase;
VTTComponent() {}
VTTComponent(uint64_t VTableIndex, BaseSubobject VTableBase)
: VTableIndex(VTableIndex), VTableBase(VTableBase) {}
};
/// VTT builder - Class for building VTT layout information.
class VTTBuilder {
ASTContext &Ctx;
/// MostDerivedClass - The most derived class for which we're building this
/// vtable.
const CXXRecordDecl *MostDerivedClass;
typedef SmallVector<VTTVTable, 64> VTTVTablesVectorTy;
/// VTTVTables - The VTT vtables.
VTTVTablesVectorTy VTTVTables;
typedef SmallVector<VTTComponent, 64> VTTComponentsVectorTy;
/// VTTComponents - The VTT components.
VTTComponentsVectorTy VTTComponents;
/// MostDerivedClassLayout - the AST record layout of the most derived class.
const ASTRecordLayout &MostDerivedClassLayout;
typedef llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBasesSetTy;
typedef llvm::DenseMap<BaseSubobject, uint64_t> AddressPointsMapTy;
/// SubVTTIndicies - The sub-VTT indices for the bases of the most derived
/// class.
llvm::DenseMap<BaseSubobject, uint64_t> SubVTTIndicies;
/// SecondaryVirtualPointerIndices - The secondary virtual pointer indices of
/// all subobjects of the most derived class.
llvm::DenseMap<BaseSubobject, uint64_t> SecondaryVirtualPointerIndices;
/// GenerateDefinition - Whether the VTT builder should generate LLVM IR for
/// the VTT.
bool GenerateDefinition;
/// AddVTablePointer - Add a vtable pointer to the VTT currently being built.
///
/// \param AddressPoints - If the vtable is a construction vtable, this has
/// the address points for it.
void AddVTablePointer(BaseSubobject Base, uint64_t VTableIndex,
const CXXRecordDecl *VTableClass);
/// LayoutSecondaryVTTs - Lay out the secondary VTTs of the given base
/// subobject.
void LayoutSecondaryVTTs(BaseSubobject Base);
/// LayoutSecondaryVirtualPointers - Lay out the secondary virtual pointers
/// for the given base subobject.
///
/// \param BaseIsMorallyVirtual whether the base subobject is a virtual base
/// or a direct or indirect base of a virtual base.
///
/// \param AddressPoints - If the vtable is a construction vtable, this has
/// the address points for it.
void LayoutSecondaryVirtualPointers(BaseSubobject Base,
bool BaseIsMorallyVirtual,
uint64_t VTableIndex,
const CXXRecordDecl *VTableClass,
VisitedVirtualBasesSetTy &VBases);
/// LayoutSecondaryVirtualPointers - Lay out the secondary virtual pointers
/// for the given base subobject.
///
/// \param AddressPoints - If the vtable is a construction vtable, this has
/// the address points for it.
void LayoutSecondaryVirtualPointers(BaseSubobject Base,
uint64_t VTableIndex);
/// LayoutVirtualVTTs - Lay out the VTTs for the virtual base classes of the
/// given record decl.
void LayoutVirtualVTTs(const CXXRecordDecl *RD,
VisitedVirtualBasesSetTy &VBases);
/// LayoutVTT - Will lay out the VTT for the given subobject, including any
/// secondary VTTs, secondary virtual pointers and virtual VTTs.
void LayoutVTT(BaseSubobject Base, bool BaseIsVirtual);
public:
VTTBuilder(ASTContext &Ctx, const CXXRecordDecl *MostDerivedClass,
bool GenerateDefinition);
// getVTTComponents - Returns a reference to the VTT components.
const VTTComponentsVectorTy &getVTTComponents() const {
return VTTComponents;
}
// getVTTVTables - Returns a reference to the VTT vtables.
const VTTVTablesVectorTy &getVTTVTables() const {
return VTTVTables;
}
/// getSubVTTIndicies - Returns a reference to the sub-VTT indices.
const llvm::DenseMap<BaseSubobject, uint64_t> &getSubVTTIndicies() const {
return SubVTTIndicies;
}
/// getSecondaryVirtualPointerIndices - Returns a reference to the secondary
/// virtual pointer indices.
const llvm::DenseMap<BaseSubobject, uint64_t> &
getSecondaryVirtualPointerIndices() const {
return SecondaryVirtualPointerIndices;
}
};
VTTBuilder::VTTBuilder(ASTContext &Ctx,
const CXXRecordDecl *MostDerivedClass,
bool GenerateDefinition)
: Ctx(Ctx), MostDerivedClass(MostDerivedClass),
MostDerivedClassLayout(Ctx.getASTRecordLayout(MostDerivedClass)),
GenerateDefinition(GenerateDefinition) {
// Lay out this VTT.
LayoutVTT(BaseSubobject(MostDerivedClass, CharUnits::Zero()),
/*BaseIsVirtual=*/false);
}
llvm::Constant *GetAddrOfVTTVTable(CodeGenVTables &CGVT,
const CXXRecordDecl *MostDerivedClass,
const VTTVTable &VTable,
@ -197,184 +39,6 @@ llvm::Constant *GetAddrOfVTTVTable(CodeGenVTables &CGVT,
AddressPoints);
}
void VTTBuilder::AddVTablePointer(BaseSubobject Base, uint64_t VTableIndex,
const CXXRecordDecl *VTableClass) {
// Store the vtable pointer index if we're generating the primary VTT.
if (VTableClass == MostDerivedClass) {
assert(!SecondaryVirtualPointerIndices.count(Base) &&
"A virtual pointer index already exists for this base subobject!");
SecondaryVirtualPointerIndices[Base] = VTTComponents.size();
}
if (!GenerateDefinition) {
VTTComponents.push_back(VTTComponent());
return;
}
VTTComponents.push_back(VTTComponent(VTableIndex, Base));
}
void VTTBuilder::LayoutSecondaryVTTs(BaseSubobject Base) {
const CXXRecordDecl *RD = Base.getBase();
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
// Don't layout virtual bases.
if (I->isVirtual())
continue;
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
CharUnits BaseOffset = Base.getBaseOffset() +
Layout.getBaseClassOffset(BaseDecl);
// Layout the VTT for this base.
LayoutVTT(BaseSubobject(BaseDecl, BaseOffset), /*BaseIsVirtual=*/false);
}
}
void
VTTBuilder::LayoutSecondaryVirtualPointers(BaseSubobject Base,
bool BaseIsMorallyVirtual,
uint64_t VTableIndex,
const CXXRecordDecl *VTableClass,
VisitedVirtualBasesSetTy &VBases) {
const CXXRecordDecl *RD = Base.getBase();
// We're not interested in bases that don't have virtual bases, and not
// morally virtual bases.
if (!RD->getNumVBases() && !BaseIsMorallyVirtual)
return;
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());
// Itanium C++ ABI 2.6.2:
// Secondary virtual pointers are present for all bases with either
// virtual bases or virtual function declarations overridden along a
// virtual path.
//
// If the base class is not dynamic, we don't want to add it, nor any
// of its base classes.
if (!BaseDecl->isDynamicClass())
continue;
bool BaseDeclIsMorallyVirtual = BaseIsMorallyVirtual;
bool BaseDeclIsNonVirtualPrimaryBase = false;
CharUnits BaseOffset;
if (I->isVirtual()) {
// Ignore virtual bases that we've already visited.
if (!VBases.insert(BaseDecl))
continue;
BaseOffset = MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
BaseDeclIsMorallyVirtual = true;
} else {
const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
BaseOffset = Base.getBaseOffset() +
Layout.getBaseClassOffset(BaseDecl);
if (!Layout.isPrimaryBaseVirtual() &&
Layout.getPrimaryBase() == BaseDecl)
BaseDeclIsNonVirtualPrimaryBase = true;
}
// Itanium C++ ABI 2.6.2:
// Secondary virtual pointers: for each base class X which (a) has virtual
// bases or is reachable along a virtual path from D, and (b) is not a
// non-virtual primary base, the address of the virtual table for X-in-D
// or an appropriate construction virtual table.
if (!BaseDeclIsNonVirtualPrimaryBase &&
(BaseDecl->getNumVBases() || BaseDeclIsMorallyVirtual)) {
// Add the vtable pointer.
AddVTablePointer(BaseSubobject(BaseDecl, BaseOffset), VTableIndex,
VTableClass);
}
// And lay out the secondary virtual pointers for the base class.
LayoutSecondaryVirtualPointers(BaseSubobject(BaseDecl, BaseOffset),
BaseDeclIsMorallyVirtual, VTableIndex,
VTableClass, VBases);
}
}
void
VTTBuilder::LayoutSecondaryVirtualPointers(BaseSubobject Base,
uint64_t VTableIndex) {
VisitedVirtualBasesSetTy VBases;
LayoutSecondaryVirtualPointers(Base, /*BaseIsMorallyVirtual=*/false,
VTableIndex, Base.getBase(), VBases);
}
void VTTBuilder::LayoutVirtualVTTs(const CXXRecordDecl *RD,
VisitedVirtualBasesSetTy &VBases) {
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.
if (I->isVirtual()) {
// Check if we've seen this base before.
if (!VBases.insert(BaseDecl))
continue;
CharUnits BaseOffset =
MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
LayoutVTT(BaseSubobject(BaseDecl, BaseOffset), /*BaseIsVirtual=*/true);
}
// We only need to layout virtual VTTs for this base if it actually has
// virtual bases.
if (BaseDecl->getNumVBases())
LayoutVirtualVTTs(BaseDecl, VBases);
}
}
void VTTBuilder::LayoutVTT(BaseSubobject Base, bool BaseIsVirtual) {
const CXXRecordDecl *RD = Base.getBase();
// Itanium C++ ABI 2.6.2:
// An array of virtual table addresses, called the VTT, is declared for
// each class type that has indirect or direct virtual base classes.
if (RD->getNumVBases() == 0)
return;
bool IsPrimaryVTT = Base.getBase() == MostDerivedClass;
if (!IsPrimaryVTT) {
// Remember the sub-VTT index.
SubVTTIndicies[Base] = VTTComponents.size();
}
uint64_t VTableIndex = VTTVTables.size();
VTTVTables.push_back(VTTVTable(Base, BaseIsVirtual));
// Add the primary vtable pointer.
AddVTablePointer(Base, VTableIndex, RD);
// Add the secondary VTTs.
LayoutSecondaryVTTs(Base);
// Add the secondary virtual pointers.
LayoutSecondaryVirtualPointers(Base, VTableIndex);
// If this is the primary VTT, we want to lay out virtual VTTs as well.
if (IsPrimaryVTT) {
VisitedVirtualBasesSetTy VBases;
LayoutVirtualVTTs(Base.getBase(), VBases);
}
}
}
void
CodeGenVTables::EmitVTTDefinition(llvm::GlobalVariable *VTT,
llvm::GlobalVariable::LinkageTypes Linkage,