| //===--- CGVTables.h - Emit LLVM Code for C++ vtables -----------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This contains code dealing with C++ code generation of virtual tables. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_CLANG_LIB_CODEGEN_CGVTABLES_H |
| #define LLVM_CLANG_LIB_CODEGEN_CGVTABLES_H |
| |
| #include "clang/AST/BaseSubobject.h" |
| #include "clang/AST/CharUnits.h" |
| #include "clang/AST/GlobalDecl.h" |
| #include "clang/AST/VTableBuilder.h" |
| #include "clang/Basic/ABI.h" |
| #include "llvm/ADT/DenseMap.h" |
| #include "llvm/IR/GlobalVariable.h" |
| |
| namespace clang { |
| class CXXRecordDecl; |
| |
| namespace CodeGen { |
| class CodeGenModule; |
| class ConstantArrayBuilder; |
| class ConstantStructBuilder; |
| |
| class CodeGenVTables { |
| CodeGenModule &CGM; |
| |
| VTableContextBase *VTContext; |
| |
| /// VTableAddressPointsMapTy - Address points for a single vtable. |
| typedef VTableLayout::AddressPointsMapTy VTableAddressPointsMapTy; |
| |
| typedef std::pair<const CXXRecordDecl *, BaseSubobject> BaseSubobjectPairTy; |
| 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; |
| |
| /// Cache for the pure virtual member call function. |
| llvm::Constant *PureVirtualFn = nullptr; |
| |
| /// Cache for the deleted virtual member call function. |
| llvm::Constant *DeletedVirtualFn = nullptr; |
| |
| /// Get the address of a thunk and emit it if necessary. |
| llvm::Constant *maybeEmitThunk(GlobalDecl GD, |
| const ThunkInfo &ThunkAdjustments, |
| bool ForVTable); |
| |
| void addVTableComponent(ConstantArrayBuilder &builder, |
| const VTableLayout &layout, unsigned componentIndex, |
| llvm::Constant *rtti, unsigned &nextVTableThunkIndex, |
| unsigned vtableAddressPoint, |
| bool vtableHasLocalLinkage); |
| |
| /// Add a 32-bit offset to a component relative to the vtable when using the |
| /// relative vtables ABI. The array builder points to the start of the vtable. |
| void addRelativeComponent(ConstantArrayBuilder &builder, |
| llvm::Constant *component, |
| unsigned vtableAddressPoint, |
| bool vtableHasLocalLinkage, |
| bool isCompleteDtor) const; |
| |
| /// Create a dso_local stub that will be used for a relative reference in the |
| /// relative vtable layout. This stub will just be a tail call to the original |
| /// function and propagate any function attributes from the original. If the |
| /// original function is already dso_local, the original is returned instead |
| /// and a stub is not created. |
| llvm::Function * |
| getOrCreateRelativeStub(llvm::Function *func, |
| llvm::GlobalValue::LinkageTypes stubLinkage, |
| bool isCompleteDtor) const; |
| |
| bool useRelativeLayout() const; |
| |
| llvm::Type *getVTableComponentType() const; |
| |
| public: |
| /// Add vtable components for the given vtable layout to the given |
| /// global initializer. |
| void createVTableInitializer(ConstantStructBuilder &builder, |
| const VTableLayout &layout, llvm::Constant *rtti, |
| bool vtableHasLocalLinkage); |
| |
| CodeGenVTables(CodeGenModule &CGM); |
| |
| ItaniumVTableContext &getItaniumVTableContext() { |
| return *cast<ItaniumVTableContext>(VTContext); |
| } |
| |
| MicrosoftVTableContext &getMicrosoftVTableContext() { |
| return *cast<MicrosoftVTableContext>(VTContext); |
| } |
| |
| /// 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); |
| |
| /// GenerateConstructionVTable - Generate a construction vtable for the given |
| /// base subobject. |
| llvm::GlobalVariable * |
| GenerateConstructionVTable(const CXXRecordDecl *RD, const BaseSubobject &Base, |
| bool BaseIsVirtual, |
| llvm::GlobalVariable::LinkageTypes Linkage, |
| VTableAddressPointsMapTy& AddressPoints); |
| |
| |
| /// GetAddrOfVTT - Get the address of the VTT for the given record decl. |
| llvm::GlobalVariable *GetAddrOfVTT(const CXXRecordDecl *RD); |
| |
| /// EmitVTTDefinition - Emit the definition of the given vtable. |
| void EmitVTTDefinition(llvm::GlobalVariable *VTT, |
| llvm::GlobalVariable::LinkageTypes Linkage, |
| 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 (if RTTI is enabled) and the VTT |
| /// (if the class has virtual bases). |
| void GenerateClassData(const CXXRecordDecl *RD); |
| |
| bool isVTableExternal(const CXXRecordDecl *RD); |
| |
| /// Returns the type of a vtable with the given layout. Normally a struct of |
| /// arrays of pointers, with one struct element for each vtable in the vtable |
| /// group. |
| llvm::Type *getVTableType(const VTableLayout &layout); |
| |
| /// Generate a public facing alias for the vtable and make the vtable either |
| /// hidden or private. The alias will have the original linkage and visibility |
| /// of the vtable. This is used for cases under the relative vtables ABI |
| /// when a vtable may not be dso_local. |
| void GenerateRelativeVTableAlias(llvm::GlobalVariable *VTable, |
| llvm::StringRef AliasNameRef); |
| }; |
| |
| } // end namespace CodeGen |
| } // end namespace clang |
| #endif |