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// 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_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;
int insertion_index = kNotFound;
int index = map->transitions()->Search(*name, &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);
DCHECK(key->Hash() > name->Hash());
array->SetKey(index, key);
array->SetTarget(index, array->GetTarget(index - 1));
}
array->SetKey(index, *name);
array->SetTarget(index, *target);
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 = array->Search(*name, &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());
return result;
}
} } // namespace v8::internal
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