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| 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 |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #include "src/v8.h" |
| 6 |
| 7 #include "src/ic/stub-cache.h" |
| 8 #include "src/type-info.h" |
| 9 |
| 10 namespace v8 { |
| 11 namespace internal { |
| 12 |
| 13 |
| 14 StubCache::StubCache(Isolate* isolate) : isolate_(isolate) {} |
| 15 |
| 16 |
| 17 void StubCache::Initialize() { |
| 18 DCHECK(IsPowerOf2(kPrimaryTableSize)); |
| 19 DCHECK(IsPowerOf2(kSecondaryTableSize)); |
| 20 Clear(); |
| 21 } |
| 22 |
| 23 |
| 24 static Code::Flags CommonStubCacheChecks(Name* name, Map* map, |
| 25 Code::Flags flags) { |
| 26 flags = Code::RemoveTypeAndHolderFromFlags(flags); |
| 27 |
| 28 // Validate that the name does not move on scavenge, and that we |
| 29 // can use identity checks instead of structural equality checks. |
| 30 DCHECK(!name->GetHeap()->InNewSpace(name)); |
| 31 DCHECK(name->IsUniqueName()); |
| 32 |
| 33 // The state bits are not important to the hash function because the stub |
| 34 // cache only contains handlers. Make sure that the bits are the least |
| 35 // significant so they will be the ones masked out. |
| 36 DCHECK_EQ(Code::HANDLER, Code::ExtractKindFromFlags(flags)); |
| 37 STATIC_ASSERT((Code::ICStateField::kMask & 1) == 1); |
| 38 |
| 39 // Make sure that the code type and cache holder are not included in the hash. |
| 40 DCHECK(Code::ExtractTypeFromFlags(flags) == 0); |
| 41 DCHECK(Code::ExtractCacheHolderFromFlags(flags) == 0); |
| 42 |
| 43 return flags; |
| 44 } |
| 45 |
| 46 |
| 47 Code* StubCache::Set(Name* name, Map* map, Code* code) { |
| 48 Code::Flags flags = CommonStubCacheChecks(name, map, code->flags()); |
| 49 |
| 50 // Compute the primary entry. |
| 51 int primary_offset = PrimaryOffset(name, flags, map); |
| 52 Entry* primary = entry(primary_, primary_offset); |
| 53 Code* old_code = primary->value; |
| 54 |
| 55 // If the primary entry has useful data in it, we retire it to the |
| 56 // secondary cache before overwriting it. |
| 57 if (old_code != isolate_->builtins()->builtin(Builtins::kIllegal)) { |
| 58 Map* old_map = primary->map; |
| 59 Code::Flags old_flags = |
| 60 Code::RemoveTypeAndHolderFromFlags(old_code->flags()); |
| 61 int seed = PrimaryOffset(primary->key, old_flags, old_map); |
| 62 int secondary_offset = SecondaryOffset(primary->key, old_flags, seed); |
| 63 Entry* secondary = entry(secondary_, secondary_offset); |
| 64 *secondary = *primary; |
| 65 } |
| 66 |
| 67 // Update primary cache. |
| 68 primary->key = name; |
| 69 primary->value = code; |
| 70 primary->map = map; |
| 71 isolate()->counters()->megamorphic_stub_cache_updates()->Increment(); |
| 72 return code; |
| 73 } |
| 74 |
| 75 |
| 76 Code* StubCache::Get(Name* name, Map* map, Code::Flags flags) { |
| 77 flags = CommonStubCacheChecks(name, map, flags); |
| 78 int primary_offset = PrimaryOffset(name, flags, map); |
| 79 Entry* primary = entry(primary_, primary_offset); |
| 80 if (primary->key == name && primary->map == map) { |
| 81 return primary->value; |
| 82 } |
| 83 int secondary_offset = SecondaryOffset(name, flags, primary_offset); |
| 84 Entry* secondary = entry(secondary_, secondary_offset); |
| 85 if (secondary->key == name && secondary->map == map) { |
| 86 return secondary->value; |
| 87 } |
| 88 return NULL; |
| 89 } |
| 90 |
| 91 |
| 92 void StubCache::Clear() { |
| 93 Code* empty = isolate_->builtins()->builtin(Builtins::kIllegal); |
| 94 for (int i = 0; i < kPrimaryTableSize; i++) { |
| 95 primary_[i].key = isolate()->heap()->empty_string(); |
| 96 primary_[i].map = NULL; |
| 97 primary_[i].value = empty; |
| 98 } |
| 99 for (int j = 0; j < kSecondaryTableSize; j++) { |
| 100 secondary_[j].key = isolate()->heap()->empty_string(); |
| 101 secondary_[j].map = NULL; |
| 102 secondary_[j].value = empty; |
| 103 } |
| 104 } |
| 105 |
| 106 |
| 107 void StubCache::CollectMatchingMaps(SmallMapList* types, Handle<Name> name, |
| 108 Code::Flags flags, |
| 109 Handle<Context> native_context, |
| 110 Zone* zone) { |
| 111 for (int i = 0; i < kPrimaryTableSize; i++) { |
| 112 if (primary_[i].key == *name) { |
| 113 Map* map = primary_[i].map; |
| 114 // Map can be NULL, if the stub is constant function call |
| 115 // with a primitive receiver. |
| 116 if (map == NULL) continue; |
| 117 |
| 118 int offset = PrimaryOffset(*name, flags, map); |
| 119 if (entry(primary_, offset) == &primary_[i] && |
| 120 !TypeFeedbackOracle::CanRetainOtherContext(map, *native_context)) { |
| 121 types->AddMapIfMissing(Handle<Map>(map), zone); |
| 122 } |
| 123 } |
| 124 } |
| 125 |
| 126 for (int i = 0; i < kSecondaryTableSize; i++) { |
| 127 if (secondary_[i].key == *name) { |
| 128 Map* map = secondary_[i].map; |
| 129 // Map can be NULL, if the stub is constant function call |
| 130 // with a primitive receiver. |
| 131 if (map == NULL) continue; |
| 132 |
| 133 // Lookup in primary table and skip duplicates. |
| 134 int primary_offset = PrimaryOffset(*name, flags, map); |
| 135 |
| 136 // Lookup in secondary table and add matches. |
| 137 int offset = SecondaryOffset(*name, flags, primary_offset); |
| 138 if (entry(secondary_, offset) == &secondary_[i] && |
| 139 !TypeFeedbackOracle::CanRetainOtherContext(map, *native_context)) { |
| 140 types->AddMapIfMissing(Handle<Map>(map), zone); |
| 141 } |
| 142 } |
| 143 } |
| 144 } |
| 145 } |
| 146 } // namespace v8::internal |
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