CGVTables.h revision 263508 
1//===--- CGVTables.h - Emit LLVM Code for C++ vtables -----------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This contains code dealing with C++ code generation of virtual tables.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef CLANG_CODEGEN_CGVTABLE_H
15#define CLANG_CODEGEN_CGVTABLE_H
16
17#include "clang/AST/BaseSubobject.h"
18#include "clang/AST/CharUnits.h"
19#include "clang/AST/GlobalDecl.h"
20#include "clang/AST/VTableBuilder.h"
21#include "clang/Basic/ABI.h"
22#include "llvm/ADT/DenseMap.h"
23#include "llvm/IR/GlobalVariable.h"
24
25namespace clang {
26  class CXXRecordDecl;
27
28namespace CodeGen {
29  class CodeGenModule;
30
31class CodeGenVTables {
32  CodeGenModule &CGM;
33
34  // FIXME: Consider moving ItaniumVTContext and MicrosoftVTContext into
35  // respective CXXABI classes?
36  ItaniumVTableContext ItaniumVTContext;
37  OwningPtr<MicrosoftVTableContext> MicrosoftVTContext;
38
39  /// VTableAddressPointsMapTy - Address points for a single vtable.
40  typedef llvm::DenseMap<BaseSubobject, uint64_t> VTableAddressPointsMapTy;
41
42  typedef std::pair<const CXXRecordDecl *, BaseSubobject> BaseSubobjectPairTy;
43  typedef llvm::DenseMap<BaseSubobjectPairTy, uint64_t> SubVTTIndiciesMapTy;
44
45  /// SubVTTIndicies - Contains indices into the various sub-VTTs.
46  SubVTTIndiciesMapTy SubVTTIndicies;
47
48  typedef llvm::DenseMap<BaseSubobjectPairTy, uint64_t>
49    SecondaryVirtualPointerIndicesMapTy;
50
51  /// SecondaryVirtualPointerIndices - Contains the secondary virtual pointer
52  /// indices.
53  SecondaryVirtualPointerIndicesMapTy SecondaryVirtualPointerIndices;
54
55  /// emitThunk - Emit a single thunk.
56  void emitThunk(GlobalDecl GD, const ThunkInfo &Thunk, bool ForVTable);
57
58  /// maybeEmitThunkForVTable - Emit the given thunk for the vtable if needed by
59  /// the ABI.
60  void maybeEmitThunkForVTable(GlobalDecl GD, const ThunkInfo &Thunk);
61
62public:
63  /// CreateVTableInitializer - Create a vtable initializer for the given record
64  /// decl.
65  /// \param Components - The vtable components; this is really an array of
66  /// VTableComponents.
67  llvm::Constant *CreateVTableInitializer(const CXXRecordDecl *RD,
68                                          const VTableComponent *Components,
69                                          unsigned NumComponents,
70                                const VTableLayout::VTableThunkTy *VTableThunks,
71                                          unsigned NumVTableThunks);
72
73  CodeGenVTables(CodeGenModule &CGM);
74
75  ItaniumVTableContext &getItaniumVTableContext() { return ItaniumVTContext; }
76
77  MicrosoftVTableContext &getMicrosoftVTableContext() {
78    return *MicrosoftVTContext.get();
79  }
80
81  /// getSubVTTIndex - Return the index of the sub-VTT for the base class of the
82  /// given record decl.
83  uint64_t getSubVTTIndex(const CXXRecordDecl *RD, BaseSubobject Base);
84
85  /// getSecondaryVirtualPointerIndex - Return the index in the VTT where the
86  /// virtual pointer for the given subobject is located.
87  uint64_t getSecondaryVirtualPointerIndex(const CXXRecordDecl *RD,
88                                           BaseSubobject Base);
89
90  /// getAddressPoint - Get the address point of the given subobject in the
91  /// class decl.
92  uint64_t getAddressPoint(BaseSubobject Base, const CXXRecordDecl *RD);
93
94  /// GenerateConstructionVTable - Generate a construction vtable for the given
95  /// base subobject.
96  llvm::GlobalVariable *
97  GenerateConstructionVTable(const CXXRecordDecl *RD, const BaseSubobject &Base,
98                             bool BaseIsVirtual,
99                             llvm::GlobalVariable::LinkageTypes Linkage,
100                             VTableAddressPointsMapTy& AddressPoints);
101
102
103  /// GetAddrOfVTable - Get the address of the VTT for the given record decl.
104  llvm::GlobalVariable *GetAddrOfVTT(const CXXRecordDecl *RD);
105
106  /// EmitVTTDefinition - Emit the definition of the given vtable.
107  void EmitVTTDefinition(llvm::GlobalVariable *VTT,
108                         llvm::GlobalVariable::LinkageTypes Linkage,
109                         const CXXRecordDecl *RD);
110
111  /// EmitThunks - Emit the associated thunks for the given global decl.
112  void EmitThunks(GlobalDecl GD);
113
114  /// GenerateClassData - Generate all the class data required to be
115  /// generated upon definition of a KeyFunction.  This includes the
116  /// vtable, the RTTI data structure (if RTTI is enabled) and the VTT
117  /// (if the class has virtual bases).
118  void GenerateClassData(const CXXRecordDecl *RD);
119
120  bool isVTableExternal(const CXXRecordDecl *RD);
121};
122
123} // end namespace CodeGen
124} // end namespace clang
125#endif
126