| // 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/v8.h" |
| |
| #include "src/objects.h" |
| #include "src/transitions-inl.h" |
| #include "src/utils.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| |
| Handle<TransitionArray> TransitionArray::Allocate(Isolate* isolate, |
| int number_of_transitions, |
| int slack) { |
| Handle<FixedArray> array = isolate->factory()->NewFixedArray( |
| LengthFor(number_of_transitions + slack)); |
| array->set(kPrototypeTransitionsIndex, Smi::FromInt(0)); |
| array->set(kTransitionLengthIndex, Smi::FromInt(number_of_transitions)); |
| return Handle<TransitionArray>::cast(array); |
| } |
| |
| |
| Handle<TransitionArray> TransitionArray::AllocateSimple(Isolate* isolate, |
| Handle<Map> target) { |
| Handle<FixedArray> array = |
| isolate->factory()->NewFixedArray(kSimpleTransitionSize); |
| array->set(kSimpleTransitionTarget, *target); |
| return Handle<TransitionArray>::cast(array); |
| } |
| |
| |
| void TransitionArray::NoIncrementalWriteBarrierCopyFrom(TransitionArray* origin, |
| int origin_transition, |
| int target_transition) { |
| NoIncrementalWriteBarrierSet(target_transition, |
| origin->GetKey(origin_transition), |
| origin->GetTarget(origin_transition)); |
| } |
| |
| |
| Handle<TransitionArray> TransitionArray::NewWith(Handle<Map> map, |
| Handle<Name> name, |
| Handle<Map> target, |
| SimpleTransitionFlag flag) { |
| Handle<TransitionArray> result; |
| Isolate* isolate = name->GetIsolate(); |
| |
| if (flag == SIMPLE_PROPERTY_TRANSITION) { |
| result = AllocateSimple(isolate, target); |
| } else { |
| result = Allocate(isolate, 1); |
| result->NoIncrementalWriteBarrierSet(0, *name, *target); |
| } |
| result->set_back_pointer_storage(map->GetBackPointer()); |
| return result; |
| } |
| |
| |
| Handle<TransitionArray> TransitionArray::ExtendToFullTransitionArray( |
| Handle<Map> containing_map) { |
| DCHECK(!containing_map->transitions()->IsFullTransitionArray()); |
| int nof = containing_map->transitions()->number_of_transitions(); |
| |
| // A transition array may shrink during GC. |
| Handle<TransitionArray> result = Allocate(containing_map->GetIsolate(), nof); |
| DisallowHeapAllocation no_gc; |
| int new_nof = containing_map->transitions()->number_of_transitions(); |
| if (new_nof != nof) { |
| DCHECK(new_nof == 0); |
| result->Shrink(ToKeyIndex(0)); |
| result->SetNumberOfTransitions(0); |
| } else if (nof == 1) { |
| result->NoIncrementalWriteBarrierCopyFrom( |
| containing_map->transitions(), kSimpleTransitionIndex, 0); |
| } |
| |
| result->set_back_pointer_storage( |
| containing_map->transitions()->back_pointer_storage()); |
| return result; |
| } |
| |
| |
| Handle<TransitionArray> TransitionArray::Insert(Handle<Map> map, |
| Handle<Name> name, |
| Handle<Map> target, |
| SimpleTransitionFlag flag) { |
| if (!map->HasTransitionArray()) { |
| return TransitionArray::NewWith(map, name, target, flag); |
| } |
| |
| int number_of_transitions = map->transitions()->number_of_transitions(); |
| int new_nof = number_of_transitions; |
| |
| bool is_special_transition = flag == SPECIAL_TRANSITION; |
| DCHECK_EQ(is_special_transition, IsSpecialTransition(*name)); |
| PropertyDetails details = is_special_transition |
| ? PropertyDetails(NONE, NORMAL, 0) |
| : GetTargetDetails(*name, *target); |
| |
| int insertion_index = kNotFound; |
| int index = |
| is_special_transition |
| ? map->transitions()->SearchSpecial(Symbol::cast(*name), |
| &insertion_index) |
| : map->transitions()->Search(details.type(), *name, |
| details.attributes(), &insertion_index); |
| if (index == kNotFound) { |
| ++new_nof; |
| } else { |
| insertion_index = index; |
| } |
| DCHECK(insertion_index >= 0 && insertion_index <= number_of_transitions); |
| |
| CHECK(new_nof <= kMaxNumberOfTransitions); |
| |
| if (new_nof <= map->transitions()->number_of_transitions_storage()) { |
| DisallowHeapAllocation no_gc; |
| TransitionArray* array = map->transitions(); |
| |
| if (index != kNotFound) { |
| array->SetTarget(index, *target); |
| return handle(array); |
| } |
| |
| array->SetNumberOfTransitions(new_nof); |
| for (index = number_of_transitions; index > insertion_index; --index) { |
| Name* key = array->GetKey(index - 1); |
| array->SetKey(index, key); |
| array->SetTarget(index, array->GetTarget(index - 1)); |
| } |
| array->SetKey(index, *name); |
| array->SetTarget(index, *target); |
| SLOW_DCHECK(array->IsSortedNoDuplicates()); |
| return handle(array); |
| } |
| |
| Handle<TransitionArray> result = Allocate( |
| map->GetIsolate(), new_nof, |
| Map::SlackForArraySize(number_of_transitions, kMaxNumberOfTransitions)); |
| |
| // The map's transition array may grown smaller during the allocation above as |
| // it was weakly traversed, though it is guaranteed not to disappear. Trim the |
| // result copy if needed, and recompute variables. |
| DCHECK(map->HasTransitionArray()); |
| DisallowHeapAllocation no_gc; |
| TransitionArray* array = map->transitions(); |
| if (array->number_of_transitions() != number_of_transitions) { |
| DCHECK(array->number_of_transitions() < number_of_transitions); |
| |
| number_of_transitions = array->number_of_transitions(); |
| new_nof = number_of_transitions; |
| |
| insertion_index = kNotFound; |
| index = is_special_transition ? map->transitions()->SearchSpecial( |
| Symbol::cast(*name), &insertion_index) |
| : map->transitions()->Search( |
| details.type(), *name, |
| details.attributes(), &insertion_index); |
| if (index == kNotFound) { |
| ++new_nof; |
| } else { |
| insertion_index = index; |
| } |
| DCHECK(insertion_index >= 0 && insertion_index <= number_of_transitions); |
| |
| result->Shrink(ToKeyIndex(new_nof)); |
| result->SetNumberOfTransitions(new_nof); |
| } |
| |
| if (array->HasPrototypeTransitions()) { |
| result->SetPrototypeTransitions(array->GetPrototypeTransitions()); |
| } |
| |
| DCHECK_NE(kNotFound, insertion_index); |
| for (int i = 0; i < insertion_index; ++i) { |
| result->NoIncrementalWriteBarrierCopyFrom(array, i, i); |
| } |
| result->NoIncrementalWriteBarrierSet(insertion_index, *name, *target); |
| for (int i = insertion_index; i < number_of_transitions; ++i) { |
| result->NoIncrementalWriteBarrierCopyFrom(array, i, i + 1); |
| } |
| |
| result->set_back_pointer_storage(array->back_pointer_storage()); |
| SLOW_DCHECK(result->IsSortedNoDuplicates()); |
| return result; |
| } |
| |
| |
| int TransitionArray::SearchDetails(int transition, PropertyType type, |
| PropertyAttributes attributes, |
| int* out_insertion_index) { |
| int nof_transitions = number_of_transitions(); |
| DCHECK(transition < nof_transitions); |
| Name* key = GetKey(transition); |
| bool is_data = type == FIELD || type == CONSTANT; |
| for (; transition < nof_transitions && GetKey(transition) == key; |
| transition++) { |
| Map* target = GetTarget(transition); |
| PropertyDetails target_details = GetTargetDetails(key, target); |
| |
| bool target_is_data = |
| target_details.type() == FIELD || target_details.type() == CONSTANT; |
| |
| int cmp = CompareDetails(is_data, attributes, target_is_data, |
| target_details.attributes()); |
| if (cmp == 0) { |
| return transition; |
| } else if (cmp < 0) { |
| break; |
| } |
| } |
| if (out_insertion_index != NULL) *out_insertion_index = transition; |
| return kNotFound; |
| } |
| |
| |
| int TransitionArray::Search(PropertyType type, Name* name, |
| PropertyAttributes attributes, |
| int* out_insertion_index) { |
| int transition = SearchName(name, out_insertion_index); |
| if (transition == kNotFound) { |
| return kNotFound; |
| } |
| return SearchDetails(transition, type, attributes, out_insertion_index); |
| } |
| } } // namespace v8::internal |