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Handlify JSObject::Freeze method.

Browse Source 
R=adamk@chromium.org

Review URL: https://codereview.chromium.org/24256004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16846 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
mstarzinger@chromium.org 2013-09-19 21:26:01 +00:00
parent f74c62e58b
commit 220c40542b
3 changed files with 97 additions and 64 deletions
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142
src/objects.cc
View File

@ -4593,6 +4593,18 @@ static MUST_USE_RESULT MaybeObject* CopyFastElementsToDictionary(
}
static Handle<SeededNumberDictionary> CopyFastElementsToDictionary(
Handle<FixedArrayBase> array,
int length,
Handle<SeededNumberDictionary> dict) {
Isolate* isolate = array->GetIsolate();
CALL_HEAP_FUNCTION(isolate,
CopyFastElementsToDictionary(
isolate, *array, length, *dict),
SeededNumberDictionary);
}
Handle<SeededNumberDictionary> JSObject::NormalizeElements(
Handle<JSObject> object) {
CALL_HEAP_FUNCTION(object->GetIsolate(),
@ -5408,122 +5420,114 @@ static void FreezeDictionary(Dictionary* dictionary) {
}
MUST_USE_RESULT MaybeObject* JSObject::Freeze(Isolate* isolate) {
Handle<Object> JSObject::Freeze(Handle<JSObject> object) {
// Freezing non-strict arguments should be handled elsewhere.
ASSERT(!HasNonStrictArgumentsElements());
ASSERT(!object->HasNonStrictArgumentsElements());
Heap* heap = isolate->heap();
if (object->map()->is_frozen()) return object;
if (map()->is_frozen()) return this;
if (IsAccessCheckNeeded() &&
!isolate->MayNamedAccess(this,
heap->undefined_value(),
Isolate* isolate = object->GetIsolate();
if (object->IsAccessCheckNeeded() &&
!isolate->MayNamedAccess(*object,
isolate->heap()->undefined_value(),
v8::ACCESS_KEYS)) {
isolate->ReportFailedAccessCheck(this, v8::ACCESS_KEYS);
RETURN_IF_SCHEDULED_EXCEPTION(isolate);
return heap->false_value();
isolate->ReportFailedAccessCheck(*object, v8::ACCESS_KEYS);
RETURN_HANDLE_IF_SCHEDULED_EXCEPTION(isolate, Object);
return isolate->factory()->false_value();
}
if (IsJSGlobalProxy()) {
Object* proto = GetPrototype();
if (proto->IsNull()) return this;
if (object->IsJSGlobalProxy()) {
Handle<Object> proto(object->GetPrototype(), isolate);
if (proto->IsNull()) return object;
ASSERT(proto->IsJSGlobalObject());
return JSObject::cast(proto)->Freeze(isolate);
return Freeze(Handle<JSObject>::cast(proto));
}
// It's not possible to freeze objects with external array elements
if (HasExternalArrayElements()) {
HandleScope scope(isolate);
Handle<Object> object(this, isolate);
if (object->HasExternalArrayElements()) {
Handle<Object> error =
isolate->factory()->NewTypeError(
"cant_prevent_ext_external_array_elements",
HandleVector(&object, 1));
return isolate->Throw(*error);
isolate->Throw(*error);
return Handle<Object>();
}
SeededNumberDictionary* new_element_dictionary = NULL;
if (!elements()->IsDictionary()) {
int length = IsJSArray()
? Smi::cast(JSArray::cast(this)->length())->value()
: elements()->length();
Handle<SeededNumberDictionary> new_element_dictionary;
if (!object->elements()->IsDictionary()) {
int length = object->IsJSArray()
? Smi::cast(Handle<JSArray>::cast(object)->length())->value()
: object->elements()->length();
if (length > 0) {
int capacity = 0;
int used = 0;
GetElementsCapacityAndUsage(&capacity, &used);
MaybeObject* maybe_dict = SeededNumberDictionary::Allocate(heap, used);
if (!maybe_dict->To(&new_element_dictionary)) return maybe_dict;
object->GetElementsCapacityAndUsage(&capacity, &used);
new_element_dictionary =
isolate->factory()->NewSeededNumberDictionary(used);
// Move elements to a dictionary; avoid calling NormalizeElements to avoid
// unnecessary transitions.
maybe_dict = CopyFastElementsToDictionary(isolate, elements(), length,
new_element_dictionary);
if (!maybe_dict->To(&new_element_dictionary)) return maybe_dict;
new_element_dictionary = CopyFastElementsToDictionary(
handle(object->elements()), length, new_element_dictionary);
} else {
// No existing elements, use a pre-allocated empty backing store
new_element_dictionary = heap->empty_slow_element_dictionary();
new_element_dictionary =
isolate->factory()->empty_slow_element_dictionary();
}
}
LookupResult result(isolate);
map()->LookupTransition(this, heap->frozen_symbol(), &result);
Handle<Map> old_map(object->map());
old_map->LookupTransition(*object, isolate->heap()->frozen_symbol(), &result);
if (result.IsTransition()) {
Map* transition_map = result.GetTransitionTarget();
ASSERT(transition_map->has_dictionary_elements());
ASSERT(transition_map->is_frozen());
ASSERT(!transition_map->is_extensible());
set_map(transition_map);
} else if (HasFastProperties() && map()->CanHaveMoreTransitions()) {
object->set_map(transition_map);
} else if (object->HasFastProperties() && old_map->CanHaveMoreTransitions()) {
// Create a new descriptor array with fully-frozen properties
int num_descriptors = map()->NumberOfOwnDescriptors();
DescriptorArray* new_descriptors;
MaybeObject* maybe_descriptors =
map()->instance_descriptors()->CopyUpToAddAttributes(num_descriptors,
FROZEN);
if (!maybe_descriptors->To(&new_descriptors)) return maybe_descriptors;
Map* new_map;
MaybeObject* maybe_new_map = map()->CopyReplaceDescriptors(
new_descriptors, INSERT_TRANSITION, heap->frozen_symbol());
if (!maybe_new_map->To(&new_map)) return maybe_new_map;
int num_descriptors = old_map->NumberOfOwnDescriptors();
Handle<DescriptorArray> new_descriptors =
DescriptorArray::CopyUpToAddAttributes(
handle(old_map->instance_descriptors()), num_descriptors, FROZEN);
Handle<Map> new_map = Map::CopyReplaceDescriptors(
old_map, new_descriptors, INSERT_TRANSITION,
isolate->factory()->frozen_symbol());
new_map->freeze();
new_map->set_is_extensible(false);
new_map->set_elements_kind(DICTIONARY_ELEMENTS);
set_map(new_map);
object->set_map(*new_map);
} else {
// Slow path: need to normalize properties for safety
MaybeObject* maybe = NormalizeProperties(CLEAR_INOBJECT_PROPERTIES, 0);
if (maybe->IsFailure()) return maybe;
NormalizeProperties(object, CLEAR_INOBJECT_PROPERTIES, 0);
// Create a new map, since other objects with this map may be extensible.
// TODO(adamk): Extend the NormalizedMapCache to handle non-extensible maps.
Map* new_map;
MaybeObject* maybe_copy = map()->Copy();
if (!maybe_copy->To(&new_map)) return maybe_copy;
Handle<Map> new_map = Map::Copy(handle(object->map()));
new_map->freeze();
new_map->set_is_extensible(false);
new_map->set_elements_kind(DICTIONARY_ELEMENTS);
set_map(new_map);
object->set_map(*new_map);
// Freeze dictionary-mode properties
FreezeDictionary(property_dictionary());
FreezeDictionary(object->property_dictionary());
}
ASSERT(map()->has_dictionary_elements());
if (new_element_dictionary != NULL) {
set_elements(new_element_dictionary);
ASSERT(object->map()->has_dictionary_elements());
if (!new_element_dictionary.is_null()) {
object->set_elements(*new_element_dictionary);
}
if (elements() != heap->empty_slow_element_dictionary()) {
SeededNumberDictionary* dictionary = element_dictionary();
if (object->elements() != isolate->heap()->empty_slow_element_dictionary()) {
SeededNumberDictionary* dictionary = object->element_dictionary();
// Make sure we never go back to the fast case
dictionary->set_requires_slow_elements();
// Freeze all elements in the dictionary
FreezeDictionary(dictionary);
}
return this;
return object;
}
@ -6581,6 +6585,16 @@ MaybeObject* Map::ShareDescriptor(DescriptorArray* descriptors,
}
Handle<Map> Map::CopyReplaceDescriptors(Handle<Map> map,
Handle<DescriptorArray> descriptors,
TransitionFlag flag,
Handle<Name> name) {
CALL_HEAP_FUNCTION(map->GetIsolate(),
map->CopyReplaceDescriptors(*descriptors, flag, *name),
Map);
}
MaybeObject* Map::CopyReplaceDescriptors(DescriptorArray* descriptors,
TransitionFlag flag,
Name* name,
@ -6834,6 +6848,16 @@ MaybeObject* Map::CopyInsertDescriptor(Descriptor* descriptor,
}
Handle<DescriptorArray> DescriptorArray::CopyUpToAddAttributes(
Handle<DescriptorArray> desc,
int enumeration_index,
PropertyAttributes attributes) {
CALL_HEAP_FUNCTION(desc->GetIsolate(),
desc->CopyUpToAddAttributes(enumeration_index, attributes),
DescriptorArray);
}
MaybeObject* DescriptorArray::CopyUpToAddAttributes(
int enumeration_index, PropertyAttributes attributes) {
if (enumeration_index == 0) return GetHeap()->empty_descriptor_array();

11
src/objects.h
View File

@ -2545,8 +2545,7 @@ class JSObject: public JSReceiver {
MUST_USE_RESULT MaybeObject* PreventExtensions();
// ES5 Object.freeze
MUST_USE_RESULT MaybeObject* Freeze(Isolate* isolate);
static Handle<Object> Freeze(Handle<JSObject> object);
// Called the first time an object is observed with ES7 Object.observe.
MUST_USE_RESULT MaybeObject* SetObserved(Isolate* isolate);
@ -3186,6 +3185,10 @@ class DescriptorArray: public FixedArray {
return CopyUpToAddAttributes(enumeration_index, NONE);
}
static Handle<DescriptorArray> CopyUpToAddAttributes(
Handle<DescriptorArray> desc,
int enumeration_index,
PropertyAttributes attributes);
MUST_USE_RESULT MaybeObject* CopyUpToAddAttributes(
int enumeration_index,
PropertyAttributes attributes);
@ -5788,6 +5791,10 @@ class Map: public HeapObject {
MUST_USE_RESULT MaybeObject* CopyWithPreallocatedFieldDescriptors();
static Handle<Map> CopyDropDescriptors(Handle<Map> map);
MUST_USE_RESULT MaybeObject* CopyDropDescriptors();
static Handle<Map> CopyReplaceDescriptors(Handle<Map> map,
Handle<DescriptorArray> descriptors,
TransitionFlag flag,
Handle<Name> name);
MUST_USE_RESULT MaybeObject* CopyReplaceDescriptors(
DescriptorArray* descriptors,
TransitionFlag flag,

8
src/runtime.cc
View File

@ -3073,10 +3073,12 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_ThrowGeneratorStateError) {
RUNTIME_FUNCTION(MaybeObject*, Runtime_ObjectFreeze) {
SealHandleScope shs(isolate);
HandleScope scope(isolate);
ASSERT(args.length() == 1);
CONVERT_ARG_CHECKED(JSObject, object, 0);
return object->Freeze(isolate);
CONVERT_ARG_HANDLE_CHECKED(JSObject, object, 0);
Handle<Object> result = JSObject::Freeze(object);
RETURN_IF_EMPTY_HANDLE(isolate, result);
return *result;
}