llvm-project/clang/lib/CodeGen/CGVTables.h

278 lines
10 KiB
C++

//===--- CGVTables.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.
//
//===----------------------------------------------------------------------===//
#ifndef CLANG_CODEGEN_CGVTABLE_H
#define CLANG_CODEGEN_CGVTABLE_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/GlobalVariable.h"
#include "clang/Basic/ABI.h"
#include "GlobalDecl.h"
namespace clang {
class CXXRecordDecl;
namespace CodeGen {
class CodeGenModule;
// 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;
public:
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(),
DenseMapInfo<uint64_t>::getEmptyKey());
}
static clang::CodeGen::BaseSubobject getTombstoneKey() {
return clang::CodeGen::BaseSubobject(
DenseMapInfo<const clang::CXXRecordDecl *>::getTombstoneKey(),
DenseMapInfo<uint64_t>::getTombstoneKey());
}
static unsigned getHashValue(const clang::CodeGen::BaseSubobject &Base) {
return
DenseMapInfo<const clang::CXXRecordDecl *>::getHashValue(Base.getBase()) ^
DenseMapInfo<uint64_t>::getHashValue(Base.getBaseOffset());
}
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 CodeGenVTables {
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;
/// VirtualBaseClassOffsetOffsets - Contains the vtable offset (relative to
/// the address point) in bytes where the offsets for virtual bases of a class
/// are stored.
typedef llvm::DenseMap<ClassPairTy, int64_t>
VirtualBaseClassOffsetOffsetsMapTy;
VirtualBaseClassOffsetOffsetsMapTy VirtualBaseClassOffsetOffsets;
/// 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::SmallVector<ThunkInfo, 1> ThunkInfoVectorTy;
typedef llvm::DenseMap<const CXXMethodDecl *, ThunkInfoVectorTy> ThunksMapTy;
/// Thunks - Contains all thunks that a given method decl will need.
ThunksMapTy Thunks;
// The layout entry and a bool indicating whether we've actually emitted
// the vtable.
typedef llvm::PointerIntPair<uint64_t *, 1, bool> VTableLayoutData;
typedef llvm::DenseMap<const CXXRecordDecl *, VTableLayoutData>
VTableLayoutMapTy;
/// VTableLayoutMap - Stores the vtable layout for all record decls.
/// The layout is stored as an array of 64-bit integers, where the first
/// integer is the number of vtable entries in the layout, and the subsequent
/// integers are the vtable components.
VTableLayoutMapTy VTableLayoutMap;
typedef std::pair<const CXXRecordDecl *, BaseSubobject> BaseSubobjectPairTy;
typedef llvm::DenseMap<BaseSubobjectPairTy, uint64_t> AddressPointsMapTy;
/// Address points - Address points for all vtables.
AddressPointsMapTy AddressPoints;
/// VTableAddressPointsMapTy - Address points for a single vtable.
typedef llvm::DenseMap<BaseSubobject, uint64_t> VTableAddressPointsMapTy;
typedef llvm::SmallVector<std::pair<uint64_t, ThunkInfo>, 1>
VTableThunksTy;
typedef llvm::DenseMap<const CXXRecordDecl *, VTableThunksTy>
VTableThunksMapTy;
/// VTableThunksMap - Contains thunks needed by vtables.
VTableThunksMapTy VTableThunksMap;
uint64_t getNumVTableComponents(const CXXRecordDecl *RD) const {
assert(VTableLayoutMap.count(RD) && "No vtable layout for this class!");
return VTableLayoutMap.lookup(RD).getPointer()[0];
}
const uint64_t *getVTableComponentsData(const CXXRecordDecl *RD) const {
assert(VTableLayoutMap.count(RD) && "No vtable layout for this class!");
uint64_t *Components = VTableLayoutMap.lookup(RD).getPointer();
return &Components[1];
}
typedef llvm::DenseMap<BaseSubobjectPairTy, uint64_t> SubVTTIndiciesMapTy;
/// SubVTTIndicies - Contains indices into the various sub-VTTs.
SubVTTIndiciesMapTy SubVTTIndicies;
typedef llvm::DenseMap<BaseSubobjectPairTy, uint64_t>
SecondaryVirtualPointerIndicesMapTy;
/// SecondaryVirtualPointerIndices - Contains the secondary virtual pointer
/// indices.
SecondaryVirtualPointerIndicesMapTy SecondaryVirtualPointerIndices;
/// 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);
llvm::GlobalVariable *GenerateVTT(llvm::GlobalVariable::LinkageTypes Linkage,
bool GenerateDefinition,
const CXXRecordDecl *RD);
/// EmitThunk - Emit a single thunk.
void EmitThunk(GlobalDecl GD, const ThunkInfo &Thunk);
/// ComputeVTableRelatedInformation - Compute and store all vtable related
/// information (vtable layout, vbase offset offsets, thunks etc) for the
/// given record decl.
void ComputeVTableRelatedInformation(const CXXRecordDecl *RD,
bool VTableRequired);
/// CreateVTableInitializer - Create a vtable initializer for the given record
/// decl.
/// \param Components - The vtable components; this is really an array of
/// VTableComponents.
llvm::Constant *CreateVTableInitializer(const CXXRecordDecl *RD,
const uint64_t *Components,
unsigned NumComponents,
const VTableThunksTy &VTableThunks);
public:
CodeGenVTables(CodeGenModule &CGM)
: CGM(CGM) { }
/// \brief True if the VTable of this record must be emitted in the
/// translation unit.
bool ShouldEmitVTableInThisTU(const CXXRecordDecl *RD);
/// 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, BaseSubobject Base);
/// getSecondaryVirtualPointerIndex - Return the index in the VTT where the
/// virtual pointer for the given subobject is located.
uint64_t getSecondaryVirtualPointerIndex(const CXXRecordDecl *RD,
BaseSubobject 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);
/// getVirtualBaseOffsetOffset - Return the offset in bytes (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 getVirtualBaseOffsetOffset(const CXXRecordDecl *RD,
const CXXRecordDecl *VBase);
/// getAddressPoint - Get the address point of the given subobject in the
/// class decl.
uint64_t getAddressPoint(BaseSubobject Base, const CXXRecordDecl *RD);
/// GetAddrOfVTable - Get the address of the vtable for the given record decl.
llvm::GlobalVariable *GetAddrOfVTable(const CXXRecordDecl *RD);
/// EmitVTableDefinition - Emit the definition of the given vtable.
void EmitVTableDefinition(llvm::GlobalVariable *VTable,
llvm::GlobalVariable::LinkageTypes Linkage,
const CXXRecordDecl *RD);
/// GenerateConstructionVTable - Generate a construction vtable for the given
/// base subobject.
llvm::GlobalVariable *
GenerateConstructionVTable(const CXXRecordDecl *RD, const BaseSubobject &Base,
bool BaseIsVirtual,
VTableAddressPointsMapTy& AddressPoints);
llvm::GlobalVariable *getVTT(const CXXRecordDecl *RD);
/// EmitThunks - Emit the associated thunks for the given global decl.
void EmitThunks(GlobalDecl GD);
/// GenerateClassData - Generate all the class data required 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);
};
} // end namespace CodeGen
} // end namespace clang
#endif