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1//===- sanitizer_dense_map_info.h - Type traits for DenseMap ----*- 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-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef SANITIZER_DENSE_MAP_INFO_H10#define SANITIZER_DENSE_MAP_INFO_H11 12#include "sanitizer_common.h"13#include "sanitizer_internal_defs.h"14#include "sanitizer_type_traits.h"15 16namespace __sanitizer {17 18namespace detail {19 20/// Simplistic combination of 32-bit hash values into 32-bit hash values.21static constexpr unsigned combineHashValue(unsigned a, unsigned b) {22 u64 key = (u64)a << 32 | (u64)b;23 key += ~(key << 32);24 key ^= (key >> 22);25 key += ~(key << 13);26 key ^= (key >> 8);27 key += (key << 3);28 key ^= (key >> 15);29 key += ~(key << 27);30 key ^= (key >> 31);31 return (unsigned)key;32}33 34// We extend a pair to allow users to override the bucket type with their own35// implementation without requiring two members.36template <typename KeyT, typename ValueT>37struct DenseMapPair {38 KeyT first = {};39 ValueT second = {};40 constexpr DenseMapPair() = default;41 constexpr DenseMapPair(const KeyT &f, const ValueT &s)42 : first(f), second(s) {}43 44 template <typename KeyT2, typename ValueT2>45 constexpr DenseMapPair(KeyT2 &&f, ValueT2 &&s)46 : first(__sanitizer::forward<KeyT2>(f)),47 second(__sanitizer::forward<ValueT2>(s)) {}48 49 constexpr DenseMapPair(const DenseMapPair &other) = default;50 constexpr DenseMapPair &operator=(const DenseMapPair &other) = default;51 constexpr DenseMapPair(DenseMapPair &&other) = default;52 constexpr DenseMapPair &operator=(DenseMapPair &&other) = default;53 54 KeyT &getFirst() { return first; }55 const KeyT &getFirst() const { return first; }56 ValueT &getSecond() { return second; }57 const ValueT &getSecond() const { return second; }58};59 60} // end namespace detail61 62template <typename T>63struct DenseMapInfo {64 // static T getEmptyKey();65 // static T getTombstoneKey();66 // static unsigned getHashValue(const T &Val);67 // static bool isEqual(const T &LHS, const T &RHS);68};69 70// Provide DenseMapInfo for all pointers. Come up with sentinel pointer values71// that are aligned to alignof(T) bytes, but try to avoid requiring T to be72// complete. This allows clients to instantiate DenseMap<T*, ...> with forward73// declared key types. Assume that no pointer key type requires more than 409674// bytes of alignment.75template <typename T>76struct DenseMapInfo<T *> {77 // The following should hold, but it would require T to be complete:78 // static_assert(alignof(T) <= (1 << Log2MaxAlign),79 // "DenseMap does not support pointer keys requiring more than "80 // "Log2MaxAlign bits of alignment");81 static constexpr uptr Log2MaxAlign = 12;82 83 static constexpr T *getEmptyKey() {84 uptr Val = static_cast<uptr>(-1);85 Val <<= Log2MaxAlign;86 return reinterpret_cast<T *>(Val);87 }88 89 static constexpr T *getTombstoneKey() {90 uptr Val = static_cast<uptr>(-2);91 Val <<= Log2MaxAlign;92 return reinterpret_cast<T *>(Val);93 }94 95 static constexpr unsigned getHashValue(const T *PtrVal) {96 return (unsigned((uptr)PtrVal) >> 4) ^ (unsigned((uptr)PtrVal) >> 9);97 }98 99 static constexpr bool isEqual(const T *LHS, const T *RHS) {100 return LHS == RHS;101 }102};103 104// Provide DenseMapInfo for chars.105template <>106struct DenseMapInfo<char> {107 static constexpr char getEmptyKey() { return ~0; }108 static constexpr char getTombstoneKey() { return ~0 - 1; }109 static constexpr unsigned getHashValue(const char &Val) { return Val * 37U; }110 111 static constexpr bool isEqual(const char &LHS, const char &RHS) {112 return LHS == RHS;113 }114};115 116// Provide DenseMapInfo for unsigned chars.117template <>118struct DenseMapInfo<unsigned char> {119 static constexpr unsigned char getEmptyKey() { return ~0; }120 static constexpr unsigned char getTombstoneKey() { return ~0 - 1; }121 static constexpr unsigned getHashValue(const unsigned char &Val) {122 return Val * 37U;123 }124 125 static constexpr bool isEqual(const unsigned char &LHS,126 const unsigned char &RHS) {127 return LHS == RHS;128 }129};130 131// Provide DenseMapInfo for unsigned shorts.132template <>133struct DenseMapInfo<unsigned short> {134 static constexpr unsigned short getEmptyKey() { return 0xFFFF; }135 static constexpr unsigned short getTombstoneKey() { return 0xFFFF - 1; }136 static constexpr unsigned getHashValue(const unsigned short &Val) {137 return Val * 37U;138 }139 140 static constexpr bool isEqual(const unsigned short &LHS,141 const unsigned short &RHS) {142 return LHS == RHS;143 }144};145 146// Provide DenseMapInfo for unsigned ints.147template <>148struct DenseMapInfo<unsigned> {149 static constexpr unsigned getEmptyKey() { return ~0U; }150 static constexpr unsigned getTombstoneKey() { return ~0U - 1; }151 static constexpr unsigned getHashValue(const unsigned &Val) {152 return Val * 37U;153 }154 155 static constexpr bool isEqual(const unsigned &LHS, const unsigned &RHS) {156 return LHS == RHS;157 }158};159 160// Provide DenseMapInfo for unsigned longs.161template <>162struct DenseMapInfo<unsigned long> {163 static constexpr unsigned long getEmptyKey() { return ~0UL; }164 static constexpr unsigned long getTombstoneKey() { return ~0UL - 1L; }165 166 static constexpr unsigned getHashValue(const unsigned long &Val) {167 return (unsigned)(Val * 37UL);168 }169 170 static constexpr bool isEqual(const unsigned long &LHS,171 const unsigned long &RHS) {172 return LHS == RHS;173 }174};175 176// Provide DenseMapInfo for unsigned long longs.177template <>178struct DenseMapInfo<unsigned long long> {179 static constexpr unsigned long long getEmptyKey() { return ~0ULL; }180 static constexpr unsigned long long getTombstoneKey() { return ~0ULL - 1ULL; }181 182 static constexpr unsigned getHashValue(const unsigned long long &Val) {183 return (unsigned)(Val * 37ULL);184 }185 186 static constexpr bool isEqual(const unsigned long long &LHS,187 const unsigned long long &RHS) {188 return LHS == RHS;189 }190};191 192// Provide DenseMapInfo for shorts.193template <>194struct DenseMapInfo<short> {195 static constexpr short getEmptyKey() { return 0x7FFF; }196 static constexpr short getTombstoneKey() { return -0x7FFF - 1; }197 static constexpr unsigned getHashValue(const short &Val) { return Val * 37U; }198 static constexpr bool isEqual(const short &LHS, const short &RHS) {199 return LHS == RHS;200 }201};202 203// Provide DenseMapInfo for ints.204template <>205struct DenseMapInfo<int> {206 static constexpr int getEmptyKey() { return 0x7fffffff; }207 static constexpr int getTombstoneKey() { return -0x7fffffff - 1; }208 static constexpr unsigned getHashValue(const int &Val) {209 return (unsigned)(Val * 37U);210 }211 212 static constexpr bool isEqual(const int &LHS, const int &RHS) {213 return LHS == RHS;214 }215};216 217// Provide DenseMapInfo for longs.218template <>219struct DenseMapInfo<long> {220 static constexpr long getEmptyKey() {221 return (1UL << (sizeof(long) * 8 - 1)) - 1UL;222 }223 224 static constexpr long getTombstoneKey() { return getEmptyKey() - 1L; }225 226 static constexpr unsigned getHashValue(const long &Val) {227 return (unsigned)(Val * 37UL);228 }229 230 static constexpr bool isEqual(const long &LHS, const long &RHS) {231 return LHS == RHS;232 }233};234 235// Provide DenseMapInfo for long longs.236template <>237struct DenseMapInfo<long long> {238 static constexpr long long getEmptyKey() { return 0x7fffffffffffffffLL; }239 static constexpr long long getTombstoneKey() {240 return -0x7fffffffffffffffLL - 1;241 }242 243 static constexpr unsigned getHashValue(const long long &Val) {244 return (unsigned)(Val * 37ULL);245 }246 247 static constexpr bool isEqual(const long long &LHS, const long long &RHS) {248 return LHS == RHS;249 }250};251 252// Provide DenseMapInfo for all pairs whose members have info.253template <typename T, typename U>254struct DenseMapInfo<detail::DenseMapPair<T, U>> {255 using Pair = detail::DenseMapPair<T, U>;256 using FirstInfo = DenseMapInfo<T>;257 using SecondInfo = DenseMapInfo<U>;258 259 static constexpr Pair getEmptyKey() {260 return detail::DenseMapPair<T, U>(FirstInfo::getEmptyKey(),261 SecondInfo::getEmptyKey());262 }263 264 static constexpr Pair getTombstoneKey() {265 return detail::DenseMapPair<T, U>(FirstInfo::getTombstoneKey(),266 SecondInfo::getTombstoneKey());267 }268 269 static constexpr unsigned getHashValue(const Pair &PairVal) {270 return detail::combineHashValue(FirstInfo::getHashValue(PairVal.first),271 SecondInfo::getHashValue(PairVal.second));272 }273 274 static constexpr bool isEqual(const Pair &LHS, const Pair &RHS) {275 return FirstInfo::isEqual(LHS.first, RHS.first) &&276 SecondInfo::isEqual(LHS.second, RHS.second);277 }278};279 280} // namespace __sanitizer281 282#endif // SANITIZER_DENSE_MAP_INFO_H283