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1 // Copyright 2012 the V8 project authors. All rights reserved. | 1 // Copyright 2012 the V8 project authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 // The reason we write our own hash map instead of using unordered_map in STL, | 5 // The reason we write our own hash map instead of using unordered_map in STL, |
6 // is that STL containers use a mutex pool on debug build, which will lead to | 6 // is that STL containers use a mutex pool on debug build, which will lead to |
7 // deadlock when we are using async signal handler. | 7 // deadlock when we are using async signal handler. |
8 | 8 |
9 #ifndef V8_BASE_HASHMAP_H_ | 9 #ifndef V8_BASE_HASHMAP_H_ |
10 #define V8_BASE_HASHMAP_H_ | 10 #define V8_BASE_HASHMAP_H_ |
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48 | 48 |
49 ~TemplateHashMapImpl(); | 49 ~TemplateHashMapImpl(); |
50 | 50 |
51 // If an entry with matching key is found, returns that entry. | 51 // If an entry with matching key is found, returns that entry. |
52 // Otherwise, nullptr is returned. | 52 // Otherwise, nullptr is returned. |
53 Entry* Lookup(const Key& key, uint32_t hash) const; | 53 Entry* Lookup(const Key& key, uint32_t hash) const; |
54 | 54 |
55 // If an entry with matching key is found, returns that entry. | 55 // If an entry with matching key is found, returns that entry. |
56 // If no matching entry is found, a new entry is inserted with | 56 // If no matching entry is found, a new entry is inserted with |
57 // corresponding key, key hash, and default initialized value. | 57 // corresponding key, key hash, and default initialized value. |
58 Entry* LookupOrInsert(const Key& key, uint32_t hash, | 58 Entry* LookupOrInsert(const Key& key, uint32_t hash); |
59 AllocationPolicy allocator = AllocationPolicy()); | |
60 | 59 |
61 Entry* InsertNew(const Key& key, uint32_t hash, | 60 Entry* InsertNew(const Key& key, uint32_t hash); |
62 AllocationPolicy allocator = AllocationPolicy()); | |
63 | 61 |
64 // Removes the entry with matching key. | 62 // Removes the entry with matching key. |
65 // It returns the value of the deleted entry | 63 // It returns the value of the deleted entry |
66 // or null if there is no value for such key. | 64 // or null if there is no value for such key. |
67 Value Remove(const Key& key, uint32_t hash); | 65 Value Remove(const Key& key, uint32_t hash); |
68 | 66 |
69 // Empties the hash map (occupancy() == 0). | 67 // Empties the hash map (occupancy() == 0). |
70 void Clear(); | 68 void Clear(); |
71 | 69 |
72 // The number of (non-empty) entries in the table. | 70 // The number of (non-empty) entries in the table. |
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95 static bool PointersMatch(typename MatchFunHelper<Key>::KeyRef key1, | 93 static bool PointersMatch(typename MatchFunHelper<Key>::KeyRef key1, |
96 typename MatchFunHelper<Key>::KeyRef key2) { | 94 typename MatchFunHelper<Key>::KeyRef key2) { |
97 return key1 == key2; | 95 return key1 == key2; |
98 } | 96 } |
99 | 97 |
100 private: | 98 private: |
101 MatchFun match_; | 99 MatchFun match_; |
102 Entry* map_; | 100 Entry* map_; |
103 uint32_t capacity_; | 101 uint32_t capacity_; |
104 uint32_t occupancy_; | 102 uint32_t occupancy_; |
| 103 AllocationPolicy allocator_; |
105 | 104 |
106 Entry* map_end() const { return map_ + capacity_; } | 105 Entry* map_end() const { return map_ + capacity_; } |
107 Entry* Probe(const Key& key, uint32_t hash) const; | 106 Entry* Probe(const Key& key, uint32_t hash) const; |
108 void Initialize(uint32_t capacity, AllocationPolicy allocator); | 107 void Initialize(uint32_t capacity); |
109 void Resize(AllocationPolicy allocator); | 108 void Resize(); |
110 }; | 109 }; |
111 | 110 |
112 template <typename Key> | 111 template <typename Key> |
113 struct MatchFunHelper { | 112 struct MatchFunHelper { |
114 typedef const Key& KeyRef; | 113 typedef const Key& KeyRef; |
115 typedef bool (*Fun)(KeyRef key1, KeyRef key2); | 114 typedef bool (*Fun)(KeyRef key1, KeyRef key2); |
116 }; | 115 }; |
117 | 116 |
118 template <typename Key> | 117 template <typename Key> |
119 struct MatchFunHelper<Key*> { | 118 struct MatchFunHelper<Key*> { |
120 typedef Key* KeyRef; | 119 typedef Key* KeyRef; |
121 typedef bool (*Fun)(KeyRef key1, KeyRef key2); | 120 typedef bool (*Fun)(KeyRef key1, KeyRef key2); |
122 }; | 121 }; |
123 | 122 |
124 typedef TemplateHashMapImpl<void*, void*, DefaultAllocationPolicy> HashMap; | 123 typedef TemplateHashMapImpl<void*, void*, DefaultAllocationPolicy> HashMap; |
125 | 124 |
126 template <typename Key, typename Value, class AllocationPolicy> | 125 template <typename Key, typename Value, class AllocationPolicy> |
127 TemplateHashMapImpl<Key, Value, AllocationPolicy>::TemplateHashMapImpl( | 126 TemplateHashMapImpl<Key, Value, AllocationPolicy>::TemplateHashMapImpl( |
128 MatchFun match, uint32_t initial_capacity, AllocationPolicy allocator) { | 127 MatchFun match, uint32_t initial_capacity, AllocationPolicy allocator) |
| 128 : allocator_(allocator) { |
129 match_ = match; | 129 match_ = match; |
130 Initialize(initial_capacity, allocator); | 130 Initialize(initial_capacity); |
131 } | 131 } |
132 | 132 |
133 template <typename Key, typename Value, class AllocationPolicy> | 133 template <typename Key, typename Value, class AllocationPolicy> |
134 TemplateHashMapImpl<Key, Value, AllocationPolicy>::~TemplateHashMapImpl() { | 134 TemplateHashMapImpl<Key, Value, AllocationPolicy>::~TemplateHashMapImpl() { |
135 AllocationPolicy::Delete(map_); | 135 allocator_.Delete(map_); |
136 } | 136 } |
137 | 137 |
138 template <typename Key, typename Value, class AllocationPolicy> | 138 template <typename Key, typename Value, class AllocationPolicy> |
139 typename TemplateHashMapImpl<Key, Value, AllocationPolicy>::Entry* | 139 typename TemplateHashMapImpl<Key, Value, AllocationPolicy>::Entry* |
140 TemplateHashMapImpl<Key, Value, AllocationPolicy>::Lookup(const Key& key, | 140 TemplateHashMapImpl<Key, Value, AllocationPolicy>::Lookup(const Key& key, |
141 uint32_t hash) const { | 141 uint32_t hash) const { |
142 Entry* p = Probe(key, hash); | 142 Entry* p = Probe(key, hash); |
143 return p->exists() ? p : nullptr; | 143 return p->exists() ? p : nullptr; |
144 } | 144 } |
145 | 145 |
146 template <typename Key, typename Value, class AllocationPolicy> | 146 template <typename Key, typename Value, class AllocationPolicy> |
147 typename TemplateHashMapImpl<Key, Value, AllocationPolicy>::Entry* | 147 typename TemplateHashMapImpl<Key, Value, AllocationPolicy>::Entry* |
148 TemplateHashMapImpl<Key, Value, AllocationPolicy>::LookupOrInsert( | 148 TemplateHashMapImpl<Key, Value, AllocationPolicy>::LookupOrInsert( |
149 const Key& key, uint32_t hash, AllocationPolicy allocator) { | 149 const Key& key, uint32_t hash) { |
150 // Find a matching entry. | 150 // Find a matching entry. |
151 Entry* p = Probe(key, hash); | 151 Entry* p = Probe(key, hash); |
152 if (p->exists()) { | 152 if (p->exists()) { |
153 return p; | 153 return p; |
154 } | 154 } |
155 | 155 |
156 return InsertNew(key, hash, allocator); | 156 return InsertNew(key, hash); |
157 } | 157 } |
158 | 158 |
159 template <typename Key, typename Value, class AllocationPolicy> | 159 template <typename Key, typename Value, class AllocationPolicy> |
160 typename TemplateHashMapImpl<Key, Value, AllocationPolicy>::Entry* | 160 typename TemplateHashMapImpl<Key, Value, AllocationPolicy>::Entry* |
161 TemplateHashMapImpl<Key, Value, AllocationPolicy>::InsertNew( | 161 TemplateHashMapImpl<Key, Value, AllocationPolicy>::InsertNew(const Key& key, |
162 const Key& key, uint32_t hash, AllocationPolicy allocator) { | 162 uint32_t hash) { |
163 // Find a matching entry. | 163 // Find a matching entry. |
164 Entry* p = Probe(key, hash); | 164 Entry* p = Probe(key, hash); |
165 DCHECK(!p->exists()); | 165 DCHECK(!p->exists()); |
166 | 166 |
167 // No entry found; construct one in-place in the empty slot using placement | 167 // No entry found; construct one in-place in the empty slot using placement |
168 // new. | 168 // new. |
169 new (p) Entry(key, Value(), hash); | 169 new (p) Entry(key, Value(), hash); |
170 occupancy_++; | 170 occupancy_++; |
171 | 171 |
172 // Grow the map if we reached >= 80% occupancy. | 172 // Grow the map if we reached >= 80% occupancy. |
173 if (occupancy_ + occupancy_ / 4 >= capacity_) { | 173 if (occupancy_ + occupancy_ / 4 >= capacity_) { |
174 Resize(allocator); | 174 Resize(); |
175 p = Probe(key, hash); | 175 p = Probe(key, hash); |
176 } | 176 } |
177 | 177 |
178 return p; | 178 return p; |
179 } | 179 } |
180 | 180 |
181 template <typename Key, typename Value, class AllocationPolicy> | 181 template <typename Key, typename Value, class AllocationPolicy> |
182 Value TemplateHashMapImpl<Key, Value, AllocationPolicy>::Remove(const Key& key, | 182 Value TemplateHashMapImpl<Key, Value, AllocationPolicy>::Remove(const Key& key, |
183 uint32_t hash) { | 183 uint32_t hash) { |
184 // Lookup the entry for the key to remove. | 184 // Lookup the entry for the key to remove. |
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283 if (p >= end) { | 283 if (p >= end) { |
284 p = map_; | 284 p = map_; |
285 } | 285 } |
286 } | 286 } |
287 | 287 |
288 return p; | 288 return p; |
289 } | 289 } |
290 | 290 |
291 template <typename Key, typename Value, class AllocationPolicy> | 291 template <typename Key, typename Value, class AllocationPolicy> |
292 void TemplateHashMapImpl<Key, Value, AllocationPolicy>::Initialize( | 292 void TemplateHashMapImpl<Key, Value, AllocationPolicy>::Initialize( |
293 uint32_t capacity, AllocationPolicy allocator) { | 293 uint32_t capacity) { |
294 DCHECK(base::bits::IsPowerOfTwo32(capacity)); | 294 DCHECK(base::bits::IsPowerOfTwo32(capacity)); |
295 map_ = reinterpret_cast<Entry*>(allocator.New(capacity * sizeof(Entry))); | 295 map_ = reinterpret_cast<Entry*>(allocator_.New(capacity * sizeof(Entry))); |
296 if (map_ == nullptr) { | 296 if (map_ == nullptr) { |
297 FATAL("Out of memory: HashMap::Initialize"); | 297 FATAL("Out of memory: HashMap::Initialize"); |
298 return; | 298 return; |
299 } | 299 } |
300 capacity_ = capacity; | 300 capacity_ = capacity; |
301 Clear(); | 301 Clear(); |
302 } | 302 } |
303 | 303 |
304 template <typename Key, typename Value, class AllocationPolicy> | 304 template <typename Key, typename Value, class AllocationPolicy> |
305 void TemplateHashMapImpl<Key, Value, AllocationPolicy>::Resize( | 305 void TemplateHashMapImpl<Key, Value, AllocationPolicy>::Resize() { |
306 AllocationPolicy allocator) { | |
307 Entry* map = map_; | 306 Entry* map = map_; |
308 uint32_t n = occupancy_; | 307 uint32_t n = occupancy_; |
309 | 308 |
310 // Allocate larger map. | 309 // Allocate larger map. |
311 Initialize(capacity_ * 2, allocator); | 310 Initialize(capacity_ * 2); |
312 | 311 |
313 // Rehash all current entries. | 312 // Rehash all current entries. |
314 for (Entry* p = map; n > 0; p++) { | 313 for (Entry* p = map; n > 0; p++) { |
315 if (p->exists()) { | 314 if (p->exists()) { |
316 Entry* entry = LookupOrInsert(p->key, p->hash, allocator); | 315 Entry* entry = LookupOrInsert(p->key, p->hash); |
317 entry->value = p->value; | 316 entry->value = p->value; |
318 n--; | 317 n--; |
319 } | 318 } |
320 } | 319 } |
321 | 320 |
322 // Delete old map. | 321 // Delete old map. |
323 AllocationPolicy::Delete(map); | 322 allocator_.Delete(map); |
324 } | 323 } |
325 | 324 |
326 // A hash map for pointer keys and values with an STL-like interface. | 325 // A hash map for pointer keys and values with an STL-like interface. |
327 template <class Key, class Value, class AllocationPolicy> | 326 template <class Key, class Value, class AllocationPolicy> |
328 class TemplateHashMap | 327 class TemplateHashMap |
329 : private TemplateHashMapImpl<void*, void*, AllocationPolicy> { | 328 : private TemplateHashMapImpl<void*, void*, AllocationPolicy> { |
330 public: | 329 public: |
331 STATIC_ASSERT(sizeof(Key*) == sizeof(void*)); // NOLINT | 330 STATIC_ASSERT(sizeof(Key*) == sizeof(void*)); // NOLINT |
332 STATIC_ASSERT(sizeof(Value*) == sizeof(void*)); // NOLINT | 331 STATIC_ASSERT(sizeof(Value*) == sizeof(void*)); // NOLINT |
333 struct value_type { | 332 struct value_type { |
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361 void*, void*, AllocationPolicy>::MatchFun match, | 360 void*, void*, AllocationPolicy>::MatchFun match, |
362 AllocationPolicy allocator = AllocationPolicy()) | 361 AllocationPolicy allocator = AllocationPolicy()) |
363 : TemplateHashMapImpl<void*, void*, AllocationPolicy>( | 362 : TemplateHashMapImpl<void*, void*, AllocationPolicy>( |
364 match, | 363 match, |
365 TemplateHashMapImpl<void*, void*, | 364 TemplateHashMapImpl<void*, void*, |
366 AllocationPolicy>::kDefaultHashMapCapacity, | 365 AllocationPolicy>::kDefaultHashMapCapacity, |
367 allocator) {} | 366 allocator) {} |
368 | 367 |
369 Iterator begin() const { return Iterator(this, this->Start()); } | 368 Iterator begin() const { return Iterator(this, this->Start()); } |
370 Iterator end() const { return Iterator(this, nullptr); } | 369 Iterator end() const { return Iterator(this, nullptr); } |
371 Iterator find(Key* key, bool insert = false, | 370 Iterator find(Key* key, bool insert = false) { |
372 AllocationPolicy allocator = AllocationPolicy()) { | |
373 if (insert) { | 371 if (insert) { |
374 return Iterator(this, this->LookupOrInsert(key, key->Hash(), allocator)); | 372 return Iterator(this, this->LookupOrInsert(key, key->Hash())); |
375 } | 373 } |
376 return Iterator(this, this->Lookup(key, key->Hash())); | 374 return Iterator(this, this->Lookup(key, key->Hash())); |
377 } | 375 } |
378 }; | 376 }; |
379 | 377 |
380 } // namespace base | 378 } // namespace base |
381 } // namespace v8 | 379 } // namespace v8 |
382 | 380 |
383 #endif // V8_BASE_HASHMAP_H_ | 381 #endif // V8_BASE_HASHMAP_H_ |
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