Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 1 | // Copyright 2015 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #ifndef V8_IDENTITY_MAP_H_ |
| 6 | #define V8_IDENTITY_MAP_H_ |
| 7 | |
Ben Murdoch | 097c5b2 | 2016-05-18 11:27:45 +0100 | [diff] [blame^] | 8 | #include "src/base/functional.h" |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 9 | #include "src/handles.h" |
| 10 | |
| 11 | namespace v8 { |
| 12 | namespace internal { |
| 13 | |
| 14 | // Forward declarations. |
| 15 | class Heap; |
| 16 | class Zone; |
| 17 | |
| 18 | // Base class of identity maps contains shared code for all template |
| 19 | // instantions. |
| 20 | class IdentityMapBase { |
| 21 | protected: |
| 22 | // Allow Tester to access internals, including changing the address of objects |
| 23 | // within the {keys_} array in order to simulate a moving GC. |
| 24 | friend class IdentityMapTester; |
| 25 | |
| 26 | typedef void** RawEntry; |
| 27 | |
| 28 | IdentityMapBase(Heap* heap, Zone* zone) |
| 29 | : heap_(heap), |
| 30 | zone_(zone), |
| 31 | gc_counter_(-1), |
| 32 | size_(0), |
| 33 | mask_(0), |
| 34 | keys_(nullptr), |
| 35 | values_(nullptr) {} |
| 36 | ~IdentityMapBase(); |
| 37 | |
| 38 | RawEntry GetEntry(Object* key); |
| 39 | RawEntry FindEntry(Object* key); |
Ben Murdoch | 097c5b2 | 2016-05-18 11:27:45 +0100 | [diff] [blame^] | 40 | void Clear(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 41 | |
| 42 | private: |
| 43 | // Internal implementation should not be called directly by subclasses. |
| 44 | int LookupIndex(Object* address); |
| 45 | int InsertIndex(Object* address); |
| 46 | void Rehash(); |
| 47 | void Resize(); |
| 48 | RawEntry Lookup(Object* key); |
| 49 | RawEntry Insert(Object* key); |
| 50 | int Hash(Object* address); |
| 51 | |
Ben Murdoch | 097c5b2 | 2016-05-18 11:27:45 +0100 | [diff] [blame^] | 52 | base::hash<uintptr_t> hasher_; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 53 | Heap* heap_; |
| 54 | Zone* zone_; |
| 55 | int gc_counter_; |
| 56 | int size_; |
| 57 | int mask_; |
| 58 | Object** keys_; |
| 59 | void** values_; |
| 60 | }; |
| 61 | |
| 62 | // Implements an identity map from object addresses to a given value type {V}. |
| 63 | // The map is robust w.r.t. garbage collection by synchronization with the |
| 64 | // supplied {heap}. |
| 65 | // * Keys are treated as strong roots. |
| 66 | // * SMIs are valid keys, except SMI #0. |
| 67 | // * The value type {V} must be reinterpret_cast'able to {void*} |
| 68 | // * The value type {V} must not be a heap type. |
| 69 | template <typename V> |
| 70 | class IdentityMap : public IdentityMapBase { |
| 71 | public: |
| 72 | IdentityMap(Heap* heap, Zone* zone) : IdentityMapBase(heap, zone) {} |
| 73 | |
| 74 | // Searches this map for the given key using the object's address |
| 75 | // as the identity, returning: |
| 76 | // found => a pointer to the storage location for the value |
| 77 | // not found => a pointer to a new storage location for the value |
| 78 | V* Get(Handle<Object> key) { return Get(*key); } |
| 79 | V* Get(Object* key) { return reinterpret_cast<V*>(GetEntry(key)); } |
| 80 | |
| 81 | // Searches this map for the given key using the object's address |
| 82 | // as the identity, returning: |
| 83 | // found => a pointer to the storage location for the value |
| 84 | // not found => {nullptr} |
| 85 | V* Find(Handle<Object> key) { return Find(*key); } |
| 86 | V* Find(Object* key) { return reinterpret_cast<V*>(FindEntry(key)); } |
| 87 | |
| 88 | // Set the value for the given key. |
| 89 | void Set(Handle<Object> key, V v) { Set(*key, v); } |
| 90 | void Set(Object* key, V v) { *(reinterpret_cast<V*>(GetEntry(key))) = v; } |
Ben Murdoch | 097c5b2 | 2016-05-18 11:27:45 +0100 | [diff] [blame^] | 91 | |
| 92 | // Removes all elements from the map. |
| 93 | void Clear() { IdentityMapBase::Clear(); } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 94 | }; |
| 95 | } // namespace internal |
| 96 | } // namespace v8 |
| 97 | |
| 98 | #endif // V8_IDENTITY_MAP_H_ |