/usr/include/clang/AST/VTableBuilder.h is in libclang-dev 3.0-6ubuntu3.
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//
// 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 tables.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_AST_VTABLEBUILDER_H
#define LLVM_CLANG_AST_VTABLEBUILDER_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 CXXRecordDecl;
/// 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
};
VTableComponent() { }
static VTableComponent MakeVCallOffset(CharUnits Offset) {
return VTableComponent(CK_VCallOffset, Offset);
}
static VTableComponent MakeVBaseOffset(CharUnits Offset) {
return VTableComponent(CK_VBaseOffset, Offset);
}
static VTableComponent MakeOffsetToTop(CharUnits 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));
}
static VTableComponent getFromOpaqueInteger(uint64_t I) {
return VTableComponent(I);
}
/// getKind - Get the kind of this vtable component.
Kind getKind() const {
return (Kind)(Value & 0x7);
}
CharUnits getVCallOffset() const {
assert(getKind() == CK_VCallOffset && "Invalid component kind!");
return getOffset();
}
CharUnits getVBaseOffset() const {
assert(getKind() == CK_VBaseOffset && "Invalid component kind!");
return getOffset();
}
CharUnits 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, CharUnits Offset) {
assert((ComponentKind == CK_VCallOffset ||
ComponentKind == CK_VBaseOffset ||
ComponentKind == CK_OffsetToTop) && "Invalid component kind!");
assert(Offset.getQuantity() <= ((1LL << 56) - 1) && "Offset is too big!");
Value = ((Offset.getQuantity() << 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;
}
CharUnits getOffset() const {
assert((getKind() == CK_VCallOffset || getKind() == CK_VBaseOffset ||
getKind() == CK_OffsetToTop) && "Invalid component kind!");
return CharUnits::fromQuantity(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);
}
explicit VTableComponent(uint64_t Value)
: Value(Value) { }
/// 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;
};
class VTableLayout {
public:
typedef std::pair<uint64_t, ThunkInfo> VTableThunkTy;
typedef SmallVector<ThunkInfo, 1> ThunkInfoVectorTy;
typedef const VTableComponent *vtable_component_iterator;
typedef const VTableThunkTy *vtable_thunk_iterator;
typedef llvm::DenseMap<BaseSubobject, uint64_t> AddressPointsMapTy;
private:
uint64_t NumVTableComponents;
VTableComponent *VTableComponents;
/// VTableThunks - Contains thunks needed by vtables.
uint64_t NumVTableThunks;
VTableThunkTy *VTableThunks;
/// Address points - Address points for all vtables.
AddressPointsMapTy AddressPoints;
public:
VTableLayout(uint64_t NumVTableComponents,
const VTableComponent *VTableComponents,
uint64_t NumVTableThunks,
const VTableThunkTy *VTableThunks,
const AddressPointsMapTy &AddressPoints);
~VTableLayout();
uint64_t getNumVTableComponents() const {
return NumVTableComponents;
}
vtable_component_iterator vtable_component_begin() const {
return VTableComponents;
}
vtable_component_iterator vtable_component_end() const {
return VTableComponents+NumVTableComponents;
}
uint64_t getNumVTableThunks() const {
return NumVTableThunks;
}
vtable_thunk_iterator vtable_thunk_begin() const {
return VTableThunks;
}
vtable_thunk_iterator vtable_thunk_end() const {
return VTableThunks+NumVTableThunks;
}
uint64_t getAddressPoint(BaseSubobject Base) const {
assert(AddressPoints.count(Base) &&
"Did not find address point!");
uint64_t AddressPoint = AddressPoints.lookup(Base);
assert(AddressPoint && "Address point must not be zero!");
return AddressPoint;
}
const AddressPointsMapTy &getAddressPoints() const {
return AddressPoints;
}
};
class VTableContext {
ASTContext &Context;
public:
typedef SmallVector<std::pair<uint64_t, ThunkInfo>, 1>
VTableThunksTy;
typedef SmallVector<ThunkInfo, 1> ThunkInfoVectorTy;
private:
/// 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 llvm::DenseMap<const CXXRecordDecl *, const VTableLayout *>
VTableLayoutMapTy;
VTableLayoutMapTy VTableLayouts;
/// NumVirtualFunctionPointers - Contains the number of virtual function
/// pointers in the vtable for a given record decl.
llvm::DenseMap<const CXXRecordDecl *, uint64_t> NumVirtualFunctionPointers;
typedef std::pair<const CXXRecordDecl *,
const CXXRecordDecl *> ClassPairTy;
/// VirtualBaseClassOffsetOffsets - Contains the vtable offset (relative to
/// the address point) in chars where the offsets for virtual bases of a class
/// are stored.
typedef llvm::DenseMap<ClassPairTy, CharUnits>
VirtualBaseClassOffsetOffsetsMapTy;
VirtualBaseClassOffsetOffsetsMapTy VirtualBaseClassOffsetOffsets;
typedef llvm::DenseMap<const CXXMethodDecl *, ThunkInfoVectorTy> ThunksMapTy;
/// Thunks - Contains all thunks that a given method decl will need.
ThunksMapTy Thunks;
void ComputeMethodVTableIndices(const CXXRecordDecl *RD);
/// 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);
public:
VTableContext(ASTContext &Context) : Context(Context) {}
~VTableContext();
const VTableLayout &getVTableLayout(const CXXRecordDecl *RD) {
ComputeVTableRelatedInformation(RD);
assert(VTableLayouts.count(RD) && "No layout for this record decl!");
return *VTableLayouts[RD];
}
VTableLayout *
createConstructionVTableLayout(const CXXRecordDecl *MostDerivedClass,
CharUnits MostDerivedClassOffset,
bool MostDerivedClassIsVirtual,
const CXXRecordDecl *LayoutClass);
const ThunkInfoVectorTy *getThunkInfo(const CXXMethodDecl *MD) {
ComputeVTableRelatedInformation(MD->getParent());
ThunksMapTy::const_iterator I = Thunks.find(MD);
if (I == Thunks.end()) {
// We did not find a thunk for this method.
return 0;
}
return &I->second;
}
/// getNumVirtualFunctionPointers - Return the number of virtual function
/// pointers in the vtable for a given record decl.
uint64_t getNumVirtualFunctionPointers(const CXXRecordDecl *RD);
/// 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 chars (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.
CharUnits getVirtualBaseOffsetOffset(const CXXRecordDecl *RD,
const CXXRecordDecl *VBase);
};
}
#endif
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