1 //===- llvm/ADT/DenseMapInfo.h - Type traits for DenseMap -------*- 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 file defines DenseMapInfo traits for DenseMap.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_ADT_DENSEMAPINFO_H
15 #define LLVM_ADT_DENSEMAPINFO_H
16 
17 #include "llvm/Support/PointerLikeTypeTraits.h"
18 #include "llvm/Support/type_traits.h"
19 
20 namespace llvm {
21 
22 template<typename T>
23 struct DenseMapInfo {
24   //static inline T getEmptyKey();
25   //static inline T getTombstoneKey();
26   //static unsigned getHashValue(const T &Val);
27   //static bool isEqual(const T &LHS, const T &RHS);
28 };
29 
30 // Provide DenseMapInfo for all pointers.
31 template<typename T>
32 struct DenseMapInfo<T*> {
33   static inline T* getEmptyKey() {
34     uintptr_t Val = static_cast<uintptr_t>(-1);
35     Val <<= PointerLikeTypeTraits<T*>::NumLowBitsAvailable;
36     return reinterpret_cast<T*>(Val);
37   }
38   static inline T* getTombstoneKey() {
39     uintptr_t Val = static_cast<uintptr_t>(-2);
40     Val <<= PointerLikeTypeTraits<T*>::NumLowBitsAvailable;
41     return reinterpret_cast<T*>(Val);
42   }
43   static unsigned getHashValue(const T *PtrVal) {
44     return (unsigned((uintptr_t)PtrVal) >> 4) ^
45            (unsigned((uintptr_t)PtrVal) >> 9);
46   }
47   static bool isEqual(const T *LHS, const T *RHS) { return LHS == RHS; }
48 };
49 
50 // Provide DenseMapInfo for chars.
51 template<> struct DenseMapInfo<char> {
52   static inline char getEmptyKey() { return ~0; }
53   static inline char getTombstoneKey() { return ~0 - 1; }
54   static unsigned getHashValue(const char& Val) { return Val * 37U; }
55   static bool isEqual(const char &LHS, const char &RHS) {
56     return LHS == RHS;
57   }
58 };
59 
60 // Provide DenseMapInfo for unsigned ints.
61 template<> struct DenseMapInfo<unsigned> {
62   static inline unsigned getEmptyKey() { return ~0U; }
63   static inline unsigned getTombstoneKey() { return ~0U - 1; }
64   static unsigned getHashValue(const unsigned& Val) { return Val * 37U; }
65   static bool isEqual(const unsigned& LHS, const unsigned& RHS) {
66     return LHS == RHS;
67   }
68 };
69 
70 // Provide DenseMapInfo for unsigned longs.
71 template<> struct DenseMapInfo<unsigned long> {
72   static inline unsigned long getEmptyKey() { return ~0UL; }
73   static inline unsigned long getTombstoneKey() { return ~0UL - 1L; }
74   static unsigned getHashValue(const unsigned long& Val) {
75     return (unsigned)(Val * 37UL);
76   }
77   static bool isEqual(const unsigned long& LHS, const unsigned long& RHS) {
78     return LHS == RHS;
79   }
80 };
81 
82 // Provide DenseMapInfo for unsigned long longs.
83 template<> struct DenseMapInfo<unsigned long long> {
84   static inline unsigned long long getEmptyKey() { return ~0ULL; }
85   static inline unsigned long long getTombstoneKey() { return ~0ULL - 1ULL; }
86   static unsigned getHashValue(const unsigned long long& Val) {
87     return (unsigned)(Val * 37ULL);
88   }
89   static bool isEqual(const unsigned long long& LHS,
90                       const unsigned long long& RHS) {
91     return LHS == RHS;
92   }
93 };
94 
95 // Provide DenseMapInfo for ints.
96 template<> struct DenseMapInfo<int> {
97   static inline int getEmptyKey() { return 0x7fffffff; }
98   static inline int getTombstoneKey() { return -0x7fffffff - 1; }
99   static unsigned getHashValue(const int& Val) { return (unsigned)(Val * 37U); }
100   static bool isEqual(const int& LHS, const int& RHS) {
101     return LHS == RHS;
102   }
103 };
104 
105 // Provide DenseMapInfo for longs.
106 template<> struct DenseMapInfo<long> {
107   static inline long getEmptyKey() {
108     return (1UL << (sizeof(long) * 8 - 1)) - 1UL;
109   }
110   static inline long getTombstoneKey() { return getEmptyKey() - 1L; }
111   static unsigned getHashValue(const long& Val) {
112     return (unsigned)(Val * 37UL);
113   }
114   static bool isEqual(const long& LHS, const long& RHS) {
115     return LHS == RHS;
116   }
117 };
118 
119 // Provide DenseMapInfo for long longs.
120 template<> struct DenseMapInfo<long long> {
121   static inline long long getEmptyKey() { return 0x7fffffffffffffffLL; }
122   static inline long long getTombstoneKey() { return -0x7fffffffffffffffLL-1; }
123   static unsigned getHashValue(const long long& Val) {
124     return (unsigned)(Val * 37ULL);
125   }
126   static bool isEqual(const long long& LHS,
127                       const long long& RHS) {
128     return LHS == RHS;
129   }
130 };
131 
132 // Provide DenseMapInfo for all pairs whose members have info.
133 template<typename T, typename U>
134 struct DenseMapInfo<std::pair<T, U> > {
135   typedef std::pair<T, U> Pair;
136   typedef DenseMapInfo<T> FirstInfo;
137   typedef DenseMapInfo<U> SecondInfo;
138 
139   static inline Pair getEmptyKey() {
140     return std::make_pair(FirstInfo::getEmptyKey(),
141                           SecondInfo::getEmptyKey());
142   }
143   static inline Pair getTombstoneKey() {
144     return std::make_pair(FirstInfo::getTombstoneKey(),
145                           SecondInfo::getTombstoneKey());
146   }
147   static unsigned getHashValue(const Pair& PairVal) {
148     uint64_t key = (uint64_t)FirstInfo::getHashValue(PairVal.first) << 32
149           | (uint64_t)SecondInfo::getHashValue(PairVal.second);
150     key += ~(key << 32);
151     key ^= (key >> 22);
152     key += ~(key << 13);
153     key ^= (key >> 8);
154     key += (key << 3);
155     key ^= (key >> 15);
156     key += ~(key << 27);
157     key ^= (key >> 31);
158     return (unsigned)key;
159   }
160   static bool isEqual(const Pair &LHS, const Pair &RHS) {
161     return FirstInfo::isEqual(LHS.first, RHS.first) &&
162            SecondInfo::isEqual(LHS.second, RHS.second);
163   }
164 };
165 
166 } // end namespace llvm
167 
168 #endif
169