96f8f9339d
Member pointers are mangled as they would be represented at runtime. They can be a single integer literal, single decl, or a tuple with some more numbers tossed in. With Clang today, most of those numbers will be zero because we reject pointers to members of virtual bases. This change required moving VTableContextBase ownership from CodeGenVTables to ASTContext, because mangling now depends on vtable layout. I also hoisted the inheritance model helpers up to be inline static methods of MSInheritanceAttr. This makes the AST code that deals with member pointers much more readable. MSVC doesn't appear to have stable manglings of null member pointers: - Null data memptrs in function templates have a mangling collision with the first field of a non-polymorphic single inheritance class. - The mangling of null data memptrs changes if you add casts. - Large null function memptrs in class templates crash MSVC. Clang uses the class template mangling for null data memptrs and the function template mangling for null function memptrs to deal with this. Reviewers: majnemer Differential Revision: http://llvm-reviews.chandlerc.com/D2695 llvm-svn: 200857
125 lines
4.6 KiB
C++
125 lines
4.6 KiB
C++
//===--- CGVTables.h - Emit LLVM Code for C++ vtables -----------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This contains code dealing with C++ code generation of virtual tables.
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//
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//===----------------------------------------------------------------------===//
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#ifndef CLANG_CODEGEN_CGVTABLE_H
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#define CLANG_CODEGEN_CGVTABLE_H
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#include "clang/AST/BaseSubobject.h"
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#include "clang/AST/CharUnits.h"
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#include "clang/AST/GlobalDecl.h"
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#include "clang/AST/VTableBuilder.h"
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#include "clang/Basic/ABI.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/IR/GlobalVariable.h"
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namespace clang {
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class CXXRecordDecl;
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namespace CodeGen {
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class CodeGenModule;
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class CodeGenVTables {
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CodeGenModule &CGM;
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VTableContextBase *VTContext;
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/// VTableAddressPointsMapTy - Address points for a single vtable.
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typedef llvm::DenseMap<BaseSubobject, uint64_t> VTableAddressPointsMapTy;
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typedef std::pair<const CXXRecordDecl *, BaseSubobject> BaseSubobjectPairTy;
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typedef llvm::DenseMap<BaseSubobjectPairTy, uint64_t> SubVTTIndiciesMapTy;
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/// SubVTTIndicies - Contains indices into the various sub-VTTs.
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SubVTTIndiciesMapTy SubVTTIndicies;
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typedef llvm::DenseMap<BaseSubobjectPairTy, uint64_t>
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SecondaryVirtualPointerIndicesMapTy;
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/// SecondaryVirtualPointerIndices - Contains the secondary virtual pointer
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/// indices.
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SecondaryVirtualPointerIndicesMapTy SecondaryVirtualPointerIndices;
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/// emitThunk - Emit a single thunk.
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void emitThunk(GlobalDecl GD, const ThunkInfo &Thunk, bool ForVTable);
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/// maybeEmitThunkForVTable - Emit the given thunk for the vtable if needed by
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/// the ABI.
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void maybeEmitThunkForVTable(GlobalDecl GD, const ThunkInfo &Thunk);
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public:
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/// CreateVTableInitializer - Create a vtable initializer for the given record
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/// decl.
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/// \param Components - The vtable components; this is really an array of
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/// VTableComponents.
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llvm::Constant *CreateVTableInitializer(const CXXRecordDecl *RD,
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const VTableComponent *Components,
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unsigned NumComponents,
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const VTableLayout::VTableThunkTy *VTableThunks,
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unsigned NumVTableThunks);
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CodeGenVTables(CodeGenModule &CGM);
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ItaniumVTableContext &getItaniumVTableContext() {
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return *cast<ItaniumVTableContext>(VTContext);
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}
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MicrosoftVTableContext &getMicrosoftVTableContext() {
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return *cast<MicrosoftVTableContext>(VTContext);
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}
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/// getSubVTTIndex - Return the index of the sub-VTT for the base class of the
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/// given record decl.
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uint64_t getSubVTTIndex(const CXXRecordDecl *RD, BaseSubobject Base);
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/// getSecondaryVirtualPointerIndex - Return the index in the VTT where the
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/// virtual pointer for the given subobject is located.
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uint64_t getSecondaryVirtualPointerIndex(const CXXRecordDecl *RD,
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BaseSubobject Base);
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/// getAddressPoint - Get the address point of the given subobject in the
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/// class decl.
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uint64_t getAddressPoint(BaseSubobject Base, const CXXRecordDecl *RD);
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/// GenerateConstructionVTable - Generate a construction vtable for the given
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/// base subobject.
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llvm::GlobalVariable *
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GenerateConstructionVTable(const CXXRecordDecl *RD, const BaseSubobject &Base,
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bool BaseIsVirtual,
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llvm::GlobalVariable::LinkageTypes Linkage,
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VTableAddressPointsMapTy& AddressPoints);
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/// GetAddrOfVTable - Get the address of the VTT for the given record decl.
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llvm::GlobalVariable *GetAddrOfVTT(const CXXRecordDecl *RD);
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/// EmitVTTDefinition - Emit the definition of the given vtable.
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void EmitVTTDefinition(llvm::GlobalVariable *VTT,
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llvm::GlobalVariable::LinkageTypes Linkage,
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const CXXRecordDecl *RD);
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/// EmitThunks - Emit the associated thunks for the given global decl.
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void EmitThunks(GlobalDecl GD);
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/// GenerateClassData - Generate all the class data required to be
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/// generated upon definition of a KeyFunction. This includes the
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/// vtable, the RTTI data structure (if RTTI is enabled) and the VTT
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/// (if the class has virtual bases).
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void GenerateClassData(const CXXRecordDecl *RD);
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bool isVTableExternal(const CXXRecordDecl *RD);
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};
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} // end namespace CodeGen
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} // end namespace clang
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#endif
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