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[runtime] Avoid prefix PrepareForDataProperty in TransitionToDataProperty

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BUG=

Review URL: https://codereview.chromium.org/1700903002

Cr-Commit-Position: refs/heads/master@{#34018}
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verwaest 2016-02-16 00:21:08 -08:00 committed by Commit bot
parent 2f8e33526b
commit 77751e93a6
1 changed files with 38 additions and 36 deletions
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74
src/objects.cc
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@ -3164,32 +3164,30 @@ void JSObject::MigrateToMap(Handle<JSObject> object, Handle<Map> new_map,
// respective prototypes.
UpdatePrototypeUserRegistration(old_map, new_map, new_map->GetIsolate());
if (object->HasFastProperties()) {
if (!new_map->is_dictionary_map()) {
MigrateFastToFast(object, new_map);
if (old_map->is_prototype_map()) {
DCHECK(!old_map->is_stable());
DCHECK(new_map->is_stable());
// Clear out the old descriptor array to avoid problems to sharing
// the descriptor array without using an explicit.
old_map->InitializeDescriptors(
old_map->GetHeap()->empty_descriptor_array(),
LayoutDescriptor::FastPointerLayout());
// Ensure that no transition was inserted for prototype migrations.
DCHECK_EQ(0, TransitionArray::NumberOfTransitions(
old_map->raw_transitions()));
DCHECK(new_map->GetBackPointer()->IsUndefined());
}
} else {
MigrateFastToSlow(object, new_map, expected_additional_properties);
}
} else {
if (old_map->is_dictionary_map()) {
// For slow-to-fast migrations JSObject::MigrateSlowToFast()
// must be used instead.
CHECK(new_map->is_dictionary_map());
// Slow-to-slow migration is trivial.
object->set_map(*new_map);
} else if (!new_map->is_dictionary_map()) {
MigrateFastToFast(object, new_map);
if (old_map->is_prototype_map()) {
DCHECK(!old_map->is_stable());
DCHECK(new_map->is_stable());
// Clear out the old descriptor array to avoid problems to sharing
// the descriptor array without using an explicit.
old_map->InitializeDescriptors(
old_map->GetHeap()->empty_descriptor_array(),
LayoutDescriptor::FastPointerLayout());
// Ensure that no transition was inserted for prototype migrations.
DCHECK_EQ(
0, TransitionArray::NumberOfTransitions(old_map->raw_transitions()));
DCHECK(new_map->GetBackPointer()->IsUndefined());
}
} else {
MigrateFastToSlow(object, new_map, expected_additional_properties);
}
// Careful: Don't allocate here!
@ -9930,6 +9928,23 @@ bool DescriptorArray::CanHoldValue(int descriptor, Object* value) {
return false;
}
namespace {
Handle<Map> UpdateDescriptorForValue(Handle<Map> map, int descriptor,
Handle<Object> value) {
if (map->instance_descriptors()->CanHoldValue(descriptor, *value)) return map;
Isolate* isolate = map->GetIsolate();
PropertyAttributes attributes =
map->instance_descriptors()->GetDetails(descriptor).attributes();
Representation representation = value->OptimalRepresentation();
Handle<FieldType> type = value->OptimalType(isolate, representation);
return Map::ReconfigureProperty(map, descriptor, kData, attributes,
representation, type, FORCE_FIELD);
}
} // namespace
// static
Handle<Map> Map::PrepareForDataProperty(Handle<Map> map, int descriptor,
@ -9937,21 +9952,8 @@ Handle<Map> Map::PrepareForDataProperty(Handle<Map> map, int descriptor,
// Dictionaries can store any property value.
if (map->is_dictionary_map()) return map;
// Migrate to the newest map before storing the property.
map = Update(map);
Handle<DescriptorArray> descriptors(map->instance_descriptors());
if (descriptors->CanHoldValue(descriptor, *value)) return map;
Isolate* isolate = map->GetIsolate();
PropertyAttributes attributes =
descriptors->GetDetails(descriptor).attributes();
Representation representation = value->OptimalRepresentation();
Handle<FieldType> type = value->OptimalType(isolate, representation);
return ReconfigureProperty(map, descriptor, kData, attributes, representation,
type, FORCE_FIELD);
// Update to the newest map before storing the property.
return UpdateDescriptorForValue(Update(map), descriptor, value);
}
@ -9975,7 +9977,7 @@ Handle<Map> Map::TransitionToDataProperty(Handle<Map> map, Handle<Name> name,
->GetDetails(descriptor)
.attributes());
return Map::PrepareForDataProperty(transition, descriptor, value);
return UpdateDescriptorForValue(transition, descriptor, value);
}
TransitionFlag flag = INSERT_TRANSITION;