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1 //===--- BaseSubobject.h - BaseSubobject class ----------------------------===//
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 file provides a definition of the BaseSubobject class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_AST_BASESUBOBJECT_H
15 #define LLVM_CLANG_AST_BASESUBOBJECT_H
16 
17 #include "clang/AST/CharUnits.h"
18 #include "clang/AST/DeclCXX.h"
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/Support/DataTypes.h"
21 #include "llvm/Support/type_traits.h"
22 
23 namespace clang {
24 // BaseSubobject - Uniquely identifies a direct or indirect base class.
25 // Stores both the base class decl and the offset from the most derived class to
26 // the base class. Used for vtable and VTT generation.
27 class BaseSubobject {
28   /// Base - The base class declaration.
29   const CXXRecordDecl *Base;
30 
31   /// BaseOffset - The offset from the most derived class to the base class.
32   CharUnits BaseOffset;
33 
34 public:
BaseSubobject()35   BaseSubobject() { }
BaseSubobject(const CXXRecordDecl * Base,CharUnits BaseOffset)36   BaseSubobject(const CXXRecordDecl *Base, CharUnits BaseOffset)
37     : Base(Base), BaseOffset(BaseOffset) { }
38 
39   /// getBase - Returns the base class declaration.
getBase()40   const CXXRecordDecl *getBase() const { return Base; }
41 
42   /// getBaseOffset - Returns the base class offset.
getBaseOffset()43   CharUnits getBaseOffset() const { return BaseOffset; }
44 
45   friend bool operator==(const BaseSubobject &LHS, const BaseSubobject &RHS) {
46     return LHS.Base == RHS.Base && LHS.BaseOffset == RHS.BaseOffset;
47  }
48 };
49 
50 } // end namespace clang
51 
52 namespace llvm {
53 
54 template<> struct DenseMapInfo<clang::BaseSubobject> {
55   static clang::BaseSubobject getEmptyKey() {
56     return clang::BaseSubobject(
57       DenseMapInfo<const clang::CXXRecordDecl *>::getEmptyKey(),
58       clang::CharUnits::fromQuantity(DenseMapInfo<int64_t>::getEmptyKey()));
59   }
60 
61   static clang::BaseSubobject getTombstoneKey() {
62     return clang::BaseSubobject(
63       DenseMapInfo<const clang::CXXRecordDecl *>::getTombstoneKey(),
64       clang::CharUnits::fromQuantity(DenseMapInfo<int64_t>::getTombstoneKey()));
65   }
66 
67   static unsigned getHashValue(const clang::BaseSubobject &Base) {
68     typedef std::pair<const clang::CXXRecordDecl *, clang::CharUnits> PairTy;
69     return DenseMapInfo<PairTy>::getHashValue(PairTy(Base.getBase(),
70                                                      Base.getBaseOffset()));
71   }
72 
73   static bool isEqual(const clang::BaseSubobject &LHS,
74                       const clang::BaseSubobject &RHS) {
75     return LHS == RHS;
76   }
77 };
78 
79 // It's OK to treat BaseSubobject as a POD type.
80 template <> struct isPodLike<clang::BaseSubobject> {
81   static const bool value = true;
82 };
83 
84 }
85 
86 #endif
87