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//===--- CGVtable.h - 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 "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/GlobalVariable.h"
#include "GlobalDecl.h"
namespace clang {
class CXXRecordDecl;
namespace CodeGen {
class CodeGenModule;
/// ThunkAdjustment - Virtual and non-virtual adjustment for thunks.
class ThunkAdjustment {
ThunkAdjustment(int64_t NonVirtual, int64_t Virtual)
: NonVirtual(NonVirtual),
Virtual(Virtual) { }
: NonVirtual(0), Virtual(0) { }
// isEmpty - Return whether this thunk adjustment is empty.
bool isEmpty() const {
return NonVirtual == 0 && Virtual == 0;
/// NonVirtual - The non-virtual adjustment.
int64_t NonVirtual;
/// Virtual - The virtual adjustment.
int64_t Virtual;
/// CovariantThunkAdjustment - Adjustment of the 'this' pointer and the
/// return pointer for covariant thunks.
class CovariantThunkAdjustment {
CovariantThunkAdjustment(const ThunkAdjustment &ThisAdjustment,
const ThunkAdjustment &ReturnAdjustment)
: ThisAdjustment(ThisAdjustment), ReturnAdjustment(ReturnAdjustment) { }
CovariantThunkAdjustment() { }
ThunkAdjustment ThisAdjustment;
ThunkAdjustment ReturnAdjustment;
// BaseSubobject - Uniquely identifies a direct or indirect base class.
// Stores both the base class decl and the offset from the most derived class to
// the base class.
class BaseSubobject {
/// Base - The base class declaration.
const CXXRecordDecl *Base;
/// BaseOffset - The offset from the most derived class to the base class.
uint64_t BaseOffset;
BaseSubobject(const CXXRecordDecl *Base, uint64_t BaseOffset)
: Base(Base), BaseOffset(BaseOffset) { }
/// getBase - Returns the base class declaration.
const CXXRecordDecl *getBase() const { return Base; }
/// getBaseOffset - Returns the base class offset.
uint64_t getBaseOffset() const { return BaseOffset; }
friend bool operator==(const BaseSubobject &LHS, const BaseSubobject &RHS) {
return LHS.Base == RHS.Base && LHS.BaseOffset == RHS.BaseOffset;
} // end namespace CodeGen
} // end namespace clang
namespace llvm {
template<> struct DenseMapInfo<clang::CodeGen::BaseSubobject> {
static clang::CodeGen::BaseSubobject getEmptyKey() {
return clang::CodeGen::BaseSubobject(
DenseMapInfo<const clang::CXXRecordDecl *>::getEmptyKey(),
static clang::CodeGen::BaseSubobject getTombstoneKey() {
return clang::CodeGen::BaseSubobject(
DenseMapInfo<const clang::CXXRecordDecl *>::getTombstoneKey(),
static unsigned getHashValue(const clang::CodeGen::BaseSubobject &Base) {
DenseMapInfo<const clang::CXXRecordDecl *>::getHashValue(Base.getBase()) ^
static bool isEqual(const clang::CodeGen::BaseSubobject &LHS,
const clang::CodeGen::BaseSubobject &RHS) {
return LHS == RHS;
// It's OK to treat BaseSubobject as a POD type.
template <> struct isPodLike<clang::CodeGen::BaseSubobject> {
static const bool value = true;
namespace clang {
namespace CodeGen {
class CGVtableInfo {
typedef std::vector<std::pair<GlobalDecl, ThunkAdjustment> >
typedef std::pair<const CXXRecordDecl *, uint64_t> CtorVtable_t;
typedef llvm::DenseMap<CtorVtable_t, int64_t> AddrSubMap_t;
typedef llvm::DenseMap<const CXXRecordDecl *, AddrSubMap_t *> AddrMap_t;
llvm::DenseMap<const CXXRecordDecl *, AddrMap_t*> AddressPoints;
typedef llvm::DenseMap<BaseSubobject, uint64_t> AddressPointsMapTy;
CodeGenModule &CGM;
/// MethodVtableIndices - Contains the index (relative to the vtable address
/// point) where the function pointer for a virtual function is stored.
typedef llvm::DenseMap<GlobalDecl, int64_t> MethodVtableIndicesTy;
MethodVtableIndicesTy MethodVtableIndices;
typedef std::pair<const CXXRecordDecl *,
const CXXRecordDecl *> ClassPairTy;
/// VirtualBaseClassIndicies - Contains the index into the vtable where the
/// offsets for virtual bases of a class are stored.
typedef llvm::DenseMap<ClassPairTy, int64_t> VirtualBaseClassIndiciesTy;
VirtualBaseClassIndiciesTy VirtualBaseClassIndicies;
/// Vtables - All the vtables which have been defined.
llvm::DenseMap<const CXXRecordDecl *, llvm::GlobalVariable *> Vtables;
/// NumVirtualFunctionPointers - Contains the number of virtual function
/// pointers in the vtable for a given record decl.
llvm::DenseMap<const CXXRecordDecl *, uint64_t> NumVirtualFunctionPointers;
typedef llvm::DenseMap<GlobalDecl, AdjustmentVectorTy> SavedAdjustmentsTy;
SavedAdjustmentsTy SavedAdjustments;
llvm::DenseSet<const CXXRecordDecl*> SavedAdjustmentRecords;
typedef llvm::DenseMap<ClassPairTy, uint64_t> SubVTTIndiciesTy;
SubVTTIndiciesTy SubVTTIndicies;
/// getNumVirtualFunctionPointers - Return the number of virtual function
/// pointers in the vtable for a given record decl.
uint64_t getNumVirtualFunctionPointers(const CXXRecordDecl *RD);
void ComputeMethodVtableIndices(const CXXRecordDecl *RD);
/// GenerateClassData - Generate all the class data requires to be generated
/// upon definition of a KeyFunction. This includes the vtable, the
/// rtti data structure and the VTT.
/// \param Linkage - The desired linkage of the vtable, the RTTI and the VTT.
void GenerateClassData(llvm::GlobalVariable::LinkageTypes Linkage,
const CXXRecordDecl *RD);
llvm::GlobalVariable *
GenerateVtable(llvm::GlobalVariable::LinkageTypes Linkage,
bool GenerateDefinition, const CXXRecordDecl *LayoutClass,
const CXXRecordDecl *RD, uint64_t Offset, bool IsVirtual,
AddressPointsMapTy& AddressPoints);
llvm::GlobalVariable *GenerateVTT(llvm::GlobalVariable::LinkageTypes Linkage,
bool GenerateDefinition,
const CXXRecordDecl *RD);
CGVtableInfo(CodeGenModule &CGM)
: CGM(CGM) { }
/// needsVTTParameter - Return whether the given global decl needs a VTT
/// parameter, which it does if it's a base constructor or destructor with
/// virtual bases.
static bool needsVTTParameter(GlobalDecl GD);
/// getSubVTTIndex - Return the index of the sub-VTT for the base class of the
/// given record decl.
uint64_t getSubVTTIndex(const CXXRecordDecl *RD, const CXXRecordDecl *Base);
/// getMethodVtableIndex - Return the index (relative to the vtable address
/// point) where the function pointer for the given virtual function is
/// stored.
uint64_t getMethodVtableIndex(GlobalDecl GD);
/// getVirtualBaseOffsetIndex - Return the index (relative to the vtable
/// address point) where the offset of the virtual base that contains the
/// given Base is stored, otherwise, if no virtual base contains the given
/// class, return 0. Base must be a virtual base class or an unambigious
/// base.
int64_t getVirtualBaseOffsetIndex(const CXXRecordDecl *RD,
const CXXRecordDecl *VBase);
AdjustmentVectorTy *getAdjustments(GlobalDecl GD);
/// getVtableAddressPoint - returns the address point of the vtable for the
/// given record decl.
/// FIXME: This should return a list of address points.
uint64_t getVtableAddressPoint(const CXXRecordDecl *RD);
llvm::GlobalVariable *getVtable(const CXXRecordDecl *RD);
/// CtorVtableInfo - Information about a constructor vtable.
struct CtorVtableInfo {
/// Vtable - The vtable itself.
llvm::GlobalVariable *Vtable;
/// AddressPoints - The address points in this constructor vtable.
AddressPointsMapTy AddressPoints;
CtorVtableInfo() : Vtable(0) { }
CtorVtableInfo getCtorVtable(const CXXRecordDecl *RD,
const BaseSubobject &Base,
bool BaseIsVirtual);
llvm::GlobalVariable *getVTT(const CXXRecordDecl *RD);
void MaybeEmitVtable(GlobalDecl GD);
} // end namespace CodeGen
} // end namespace clang