CGVTables.h source code [clang_source_code/lib/CodeGen/CGVTables.h]

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