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| 1 // Copyright 2016 the V8 project authors. All rights reserved. | 1 // Copyright 2016 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 #ifndef V8_LOOKUP_CACHE_H_ | 5 #ifndef V8_LOOKUP_CACHE_H_ |
| 6 #define V8_LOOKUP_CACHE_H_ | 6 #define V8_LOOKUP_CACHE_H_ |
| 7 | 7 |
| 8 #include "src/objects.h" | 8 #include "src/objects.h" |
| 9 | 9 |
| 10 namespace v8 { | 10 namespace v8 { |
| (...skipping 34 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... |
| 45 Name* name; | 45 Name* name; |
| 46 }; | 46 }; |
| 47 | 47 |
| 48 Key keys_[kLength]; | 48 Key keys_[kLength]; |
| 49 int results_[kLength]; | 49 int results_[kLength]; |
| 50 | 50 |
| 51 friend class Isolate; | 51 friend class Isolate; |
| 52 DISALLOW_COPY_AND_ASSIGN(DescriptorLookupCache); | 52 DISALLOW_COPY_AND_ASSIGN(DescriptorLookupCache); |
| 53 }; | 53 }; |
| 54 | 54 |
| 55 // Cache for mapping (map, property name) into field offset. | |
| 56 // Cleared at startup and prior to mark sweep collection. | |
| 57 class KeyedLookupCache { | |
| 58 public: | |
| 59 // Lookup field offset for (map, name). If absent, -1 is returned. | |
| 60 int Lookup(Handle<Map> map, Handle<Name> name); | |
| 61 | |
| 62 // Update an element in the cache. | |
| 63 void Update(Handle<Map> map, Handle<Name> name, int field_offset); | |
| 64 | |
| 65 // Clear the cache. | |
| 66 void Clear(); | |
| 67 | |
| 68 static const int kLength = 256; | |
| 69 static const int kCapacityMask = kLength - 1; | |
| 70 static const int kMapHashShift = 5; | |
| 71 static const int kHashMask = -4; // Zero the last two bits. | |
| 72 static const int kEntriesPerBucket = 4; | |
| 73 static const int kEntryLength = 2; | |
| 74 static const int kMapIndex = 0; | |
| 75 static const int kKeyIndex = 1; | |
| 76 static const int kNotFound = -1; | |
| 77 | |
| 78 // kEntriesPerBucket should be a power of 2. | |
| 79 STATIC_ASSERT((kEntriesPerBucket & (kEntriesPerBucket - 1)) == 0); | |
| 80 STATIC_ASSERT(kEntriesPerBucket == -kHashMask); | |
| 81 | |
| 82 private: | |
| 83 KeyedLookupCache() { | |
| 84 for (int i = 0; i < kLength; ++i) { | |
| 85 keys_[i].map = NULL; | |
| 86 keys_[i].name = NULL; | |
| 87 field_offsets_[i] = kNotFound; | |
| 88 } | |
| 89 } | |
| 90 | |
| 91 static inline int Hash(Handle<Map> map, Handle<Name> name); | |
| 92 | |
| 93 // Get the address of the keys and field_offsets arrays. Used in | |
| 94 // generated code to perform cache lookups. | |
| 95 Address keys_address() { return reinterpret_cast<Address>(&keys_); } | |
| 96 | |
| 97 Address field_offsets_address() { | |
| 98 return reinterpret_cast<Address>(&field_offsets_); | |
| 99 } | |
| 100 | |
| 101 struct Key { | |
| 102 Map* map; | |
| 103 Name* name; | |
| 104 }; | |
| 105 | |
| 106 Key keys_[kLength]; | |
| 107 int field_offsets_[kLength]; | |
| 108 | |
| 109 friend class ExternalReference; | |
| 110 friend class Isolate; | |
| 111 DISALLOW_COPY_AND_ASSIGN(KeyedLookupCache); | |
| 112 }; | |
| 113 | |
| 114 } // namespace internal | 55 } // namespace internal |
| 115 } // namespace v8 | 56 } // namespace v8 |
| 116 | 57 |
| 117 #endif // V8_LOOKUP_CACHE_H_ | 58 #endif // V8_LOOKUP_CACHE_H_ |
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