| // Copyright 2012 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "src/ic/stub-cache.h" |
| |
| #include "src/base/bits.h" |
| #include "src/type-info.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| |
| StubCache::StubCache(Isolate* isolate) : isolate_(isolate) {} |
| |
| |
| void StubCache::Initialize() { |
| DCHECK(base::bits::IsPowerOfTwo32(kPrimaryTableSize)); |
| DCHECK(base::bits::IsPowerOfTwo32(kSecondaryTableSize)); |
| Clear(); |
| } |
| |
| |
| static Code::Flags CommonStubCacheChecks(Name* name, Map* map, |
| Code::Flags flags) { |
| flags = Code::RemoveHolderFromFlags(flags); |
| |
| // Validate that the name does not move on scavenge, and that we |
| // can use identity checks instead of structural equality checks. |
| DCHECK(!name->GetHeap()->InNewSpace(name)); |
| DCHECK(name->IsUniqueName()); |
| |
| // The state bits are not important to the hash function because the stub |
| // cache only contains handlers. Make sure that the bits are the least |
| // significant so they will be the ones masked out. |
| DCHECK_EQ(Code::HANDLER, Code::ExtractKindFromFlags(flags)); |
| |
| // Make sure that the cache holder are not included in the hash. |
| DCHECK(Code::ExtractCacheHolderFromFlags(flags) == 0); |
| |
| return flags; |
| } |
| |
| |
| Code* StubCache::Set(Name* name, Map* map, Code* code) { |
| Code::Flags flags = CommonStubCacheChecks(name, map, code->flags()); |
| |
| // Compute the primary entry. |
| int primary_offset = PrimaryOffset(name, flags, map); |
| Entry* primary = entry(primary_, primary_offset); |
| Code* old_code = primary->value; |
| |
| // If the primary entry has useful data in it, we retire it to the |
| // secondary cache before overwriting it. |
| if (old_code != isolate_->builtins()->builtin(Builtins::kIllegal)) { |
| Map* old_map = primary->map; |
| Code::Flags old_flags = Code::RemoveHolderFromFlags(old_code->flags()); |
| int seed = PrimaryOffset(primary->key, old_flags, old_map); |
| int secondary_offset = SecondaryOffset(primary->key, old_flags, seed); |
| Entry* secondary = entry(secondary_, secondary_offset); |
| *secondary = *primary; |
| } |
| |
| // Update primary cache. |
| primary->key = name; |
| primary->value = code; |
| primary->map = map; |
| isolate()->counters()->megamorphic_stub_cache_updates()->Increment(); |
| return code; |
| } |
| |
| |
| Code* StubCache::Get(Name* name, Map* map, Code::Flags flags) { |
| flags = CommonStubCacheChecks(name, map, flags); |
| int primary_offset = PrimaryOffset(name, flags, map); |
| Entry* primary = entry(primary_, primary_offset); |
| if (primary->key == name && primary->map == map && |
| flags == Code::RemoveHolderFromFlags(primary->value->flags())) { |
| return primary->value; |
| } |
| int secondary_offset = SecondaryOffset(name, flags, primary_offset); |
| Entry* secondary = entry(secondary_, secondary_offset); |
| if (secondary->key == name && secondary->map == map && |
| flags == Code::RemoveHolderFromFlags(secondary->value->flags())) { |
| return secondary->value; |
| } |
| return NULL; |
| } |
| |
| |
| void StubCache::Clear() { |
| Code* empty = isolate_->builtins()->builtin(Builtins::kIllegal); |
| for (int i = 0; i < kPrimaryTableSize; i++) { |
| primary_[i].key = isolate()->heap()->empty_string(); |
| primary_[i].map = NULL; |
| primary_[i].value = empty; |
| } |
| for (int j = 0; j < kSecondaryTableSize; j++) { |
| secondary_[j].key = isolate()->heap()->empty_string(); |
| secondary_[j].map = NULL; |
| secondary_[j].value = empty; |
| } |
| } |
| |
| |
| void StubCache::CollectMatchingMaps(SmallMapList* types, Handle<Name> name, |
| Code::Flags flags, |
| Handle<Context> native_context, |
| Zone* zone) { |
| for (int i = 0; i < kPrimaryTableSize; i++) { |
| if (primary_[i].key == *name) { |
| Map* map = primary_[i].map; |
| // Map can be NULL, if the stub is constant function call |
| // with a primitive receiver. |
| if (map == NULL) continue; |
| |
| int offset = PrimaryOffset(*name, flags, map); |
| if (entry(primary_, offset) == &primary_[i] && |
| TypeFeedbackOracle::IsRelevantFeedback(map, *native_context)) { |
| types->AddMapIfMissing(Handle<Map>(map), zone); |
| } |
| } |
| } |
| |
| for (int i = 0; i < kSecondaryTableSize; i++) { |
| if (secondary_[i].key == *name) { |
| Map* map = secondary_[i].map; |
| // Map can be NULL, if the stub is constant function call |
| // with a primitive receiver. |
| if (map == NULL) continue; |
| |
| // Lookup in primary table and skip duplicates. |
| int primary_offset = PrimaryOffset(*name, flags, map); |
| |
| // Lookup in secondary table and add matches. |
| int offset = SecondaryOffset(*name, flags, primary_offset); |
| if (entry(secondary_, offset) == &secondary_[i] && |
| TypeFeedbackOracle::IsRelevantFeedback(map, *native_context)) { |
| types->AddMapIfMissing(Handle<Map>(map), zone); |
| } |
| } |
| } |
| } |
| } // namespace internal |
| } // namespace v8 |