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 "llvm/ADT/DenseMap.h"
19 #include "llvm/Support/DataTypes.h"
20 #include "llvm/Support/type_traits.h"
21 
22 namespace clang {
23   class CXXRecordDecl;
24 
25 // BaseSubobject - Uniquely identifies a direct or indirect base class.
26 // Stores both the base class decl and the offset from the most derived class to
27 // the base class. Used for vtable and VTT generation.
28 class BaseSubobject {
29   /// Base - The base class declaration.
30   const CXXRecordDecl *Base;
31 
32   /// BaseOffset - The offset from the most derived class to the base class.
33   CharUnits BaseOffset;
34 
35 public:
BaseSubobject()36   BaseSubobject() { }
BaseSubobject(const CXXRecordDecl * Base,CharUnits BaseOffset)37   BaseSubobject(const CXXRecordDecl *Base, CharUnits BaseOffset)
38     : Base(Base), BaseOffset(BaseOffset) { }
39 
40   /// getBase - Returns the base class declaration.
getBase()41   const CXXRecordDecl *getBase() const { return Base; }
42 
43   /// getBaseOffset - Returns the base class offset.
getBaseOffset()44   CharUnits getBaseOffset() const { return BaseOffset; }
45 
46   friend bool operator==(const BaseSubobject &LHS, const BaseSubobject &RHS) {
47     return LHS.Base == RHS.Base && LHS.BaseOffset == RHS.BaseOffset;
48  }
49 };
50 
51 } // end namespace clang
52 
53 namespace llvm {
54 
55 template<> struct DenseMapInfo<clang::BaseSubobject> {
56   static clang::BaseSubobject getEmptyKey() {
57     return clang::BaseSubobject(
58       DenseMapInfo<const clang::CXXRecordDecl *>::getEmptyKey(),
59       clang::CharUnits::fromQuantity(DenseMapInfo<int64_t>::getEmptyKey()));
60   }
61 
62   static clang::BaseSubobject getTombstoneKey() {
63     return clang::BaseSubobject(
64       DenseMapInfo<const clang::CXXRecordDecl *>::getTombstoneKey(),
65       clang::CharUnits::fromQuantity(DenseMapInfo<int64_t>::getTombstoneKey()));
66   }
67 
68   static unsigned getHashValue(const clang::BaseSubobject &Base) {
69     typedef std::pair<const clang::CXXRecordDecl *, clang::CharUnits> PairTy;
70     return DenseMapInfo<PairTy>::getHashValue(PairTy(Base.getBase(),
71                                                      Base.getBaseOffset()));
72   }
73 
74   static bool isEqual(const clang::BaseSubobject &LHS,
75                       const clang::BaseSubobject &RHS) {
76     return LHS == RHS;
77   }
78 };
79 
80 // It's OK to treat BaseSubobject as a POD type.
81 template <> struct isPodLike<clang::BaseSubobject> {
82   static const bool value = true;
83 };
84 
85 }
86 
87 #endif
88