1 //===--- CGVTables.h - Emit LLVM Code for C++ vtables -----------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This contains code dealing with C++ code generation of virtual tables. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_CLANG_LIB_CODEGEN_CGVTABLES_H 14 #define LLVM_CLANG_LIB_CODEGEN_CGVTABLES_H 15 16 #include "clang/AST/BaseSubobject.h" 17 #include "clang/AST/CharUnits.h" 18 #include "clang/AST/GlobalDecl.h" 19 #include "clang/AST/VTableBuilder.h" 20 #include "clang/Basic/ABI.h" 21 #include "llvm/ADT/DenseMap.h" 22 #include "llvm/IR/GlobalVariable.h" 23 24 namespace clang { 25 class CXXRecordDecl; 26 27 namespace CodeGen { 28 class CodeGenModule; 29 class ConstantArrayBuilder; 30 class ConstantStructBuilder; 31 32 class CodeGenVTables { 33 CodeGenModule &CGM; 34 35 VTableContextBase *VTContext; 36 37 /// VTableAddressPointsMapTy - Address points for a single vtable. 38 typedef VTableLayout::AddressPointsMapTy VTableAddressPointsMapTy; 39 40 typedef std::pair<const CXXRecordDecl *, BaseSubobject> BaseSubobjectPairTy; 41 typedef llvm::DenseMap<BaseSubobjectPairTy, uint64_t> SubVTTIndiciesMapTy; 42 43 /// SubVTTIndicies - Contains indices into the various sub-VTTs. 44 SubVTTIndiciesMapTy SubVTTIndicies; 45 46 typedef llvm::DenseMap<BaseSubobjectPairTy, uint64_t> 47 SecondaryVirtualPointerIndicesMapTy; 48 49 /// SecondaryVirtualPointerIndices - Contains the secondary virtual pointer 50 /// indices. 51 SecondaryVirtualPointerIndicesMapTy SecondaryVirtualPointerIndices; 52 53 /// Cache for the pure virtual member call function. 54 llvm::Constant *PureVirtualFn = nullptr; 55 56 /// Cache for the deleted virtual member call function. 57 llvm::Constant *DeletedVirtualFn = nullptr; 58 59 /// Get the address of a thunk and emit it if necessary. 60 llvm::Constant *maybeEmitThunk(GlobalDecl GD, 61 const ThunkInfo &ThunkAdjustments, 62 bool ForVTable); 63 64 void addVTableComponent(ConstantArrayBuilder &builder, 65 const VTableLayout &layout, unsigned idx, 66 llvm::Constant *rtti, 67 unsigned &nextVTableThunkIndex); 68 69 public: 70 /// Add vtable components for the given vtable layout to the given 71 /// global initializer. 72 void createVTableInitializer(ConstantStructBuilder &builder, 73 const VTableLayout &layout, 74 llvm::Constant *rtti); 75 76 CodeGenVTables(CodeGenModule &CGM); 77 78 ItaniumVTableContext &getItaniumVTableContext() { 79 return *cast<ItaniumVTableContext>(VTContext); 80 } 81 82 MicrosoftVTableContext &getMicrosoftVTableContext() { 83 return *cast<MicrosoftVTableContext>(VTContext); 84 } 85 86 /// getSubVTTIndex - Return the index of the sub-VTT for the base class of the 87 /// given record decl. 88 uint64_t getSubVTTIndex(const CXXRecordDecl *RD, BaseSubobject Base); 89 90 /// getSecondaryVirtualPointerIndex - Return the index in the VTT where the 91 /// virtual pointer for the given subobject is located. 92 uint64_t getSecondaryVirtualPointerIndex(const CXXRecordDecl *RD, 93 BaseSubobject Base); 94 95 /// GenerateConstructionVTable - Generate a construction vtable for the given 96 /// base subobject. 97 llvm::GlobalVariable * 98 GenerateConstructionVTable(const CXXRecordDecl *RD, const BaseSubobject &Base, 99 bool BaseIsVirtual, 100 llvm::GlobalVariable::LinkageTypes Linkage, 101 VTableAddressPointsMapTy& AddressPoints); 102 103 104 /// GetAddrOfVTT - Get the address of the VTT for the given record decl. 105 llvm::GlobalVariable *GetAddrOfVTT(const CXXRecordDecl *RD); 106 107 /// EmitVTTDefinition - Emit the definition of the given vtable. 108 void EmitVTTDefinition(llvm::GlobalVariable *VTT, 109 llvm::GlobalVariable::LinkageTypes Linkage, 110 const CXXRecordDecl *RD); 111 112 /// EmitThunks - Emit the associated thunks for the given global decl. 113 void EmitThunks(GlobalDecl GD); 114 115 /// GenerateClassData - Generate all the class data required to be 116 /// generated upon definition of a KeyFunction. This includes the 117 /// vtable, the RTTI data structure (if RTTI is enabled) and the VTT 118 /// (if the class has virtual bases). 119 void GenerateClassData(const CXXRecordDecl *RD); 120 121 bool isVTableExternal(const CXXRecordDecl *RD); 122 123 /// Returns the type of a vtable with the given layout. Normally a struct of 124 /// arrays of pointers, with one struct element for each vtable in the vtable 125 /// group. 126 llvm::Type *getVTableType(const VTableLayout &layout); 127 }; 128 129 } // end namespace CodeGen 130 } // end namespace clang 131 #endif 132