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// Copyright 2018 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/objects/js-array-buffer.h"
#include "src/base/platform/wrappers.h"
#include "src/execution/protectors-inl.h"
#include "src/logging/counters.h"
#include "src/objects/js-array-buffer-inl.h"
#include "src/objects/property-descriptor.h"
namespace v8 {
namespace internal {
namespace {
// ES#sec-canonicalnumericindexstring
// Returns true if the lookup_key represents a valid index string.
bool CanonicalNumericIndexString(Isolate* isolate,
const PropertyKey& lookup_key,
bool* is_minus_zero) {
// 1. Assert: Type(argument) is String.
DCHECK(lookup_key.is_element() || lookup_key.name()->IsString());
*is_minus_zero = false;
if (lookup_key.is_element()) return true;
Handle<String> key = Handle<String>::cast(lookup_key.name());
// 3. Let n be ! ToNumber(argument).
Handle<Object> result = String::ToNumber(isolate, key);
if (result->IsMinusZero()) {
// 2. If argument is "-0", return -0𝔽.
// We are not performing SaveValue check for -0 because it'll be rejected
// anyway.
*is_minus_zero = true;
} else {
// 4. If SameValue(! ToString(n), argument) is false, return undefined.
Handle<String> str = Object::ToString(isolate, result).ToHandleChecked();
// Avoid treating strings like "2E1" and "20" as the same key.
if (!str->SameValue(*key)) return false;
}
return true;
}
} // anonymous namespace
void JSArrayBuffer::Setup(SharedFlag shared, ResizableFlag resizable,
std::shared_ptr<BackingStore> backing_store) {
clear_padding();
set_bit_field(0);
set_is_shared(shared == SharedFlag::kShared);
set_is_resizable(resizable == ResizableFlag::kResizable);
set_is_detachable(shared != SharedFlag::kShared);
for (int i = 0; i < v8::ArrayBuffer::kEmbedderFieldCount; i++) {
SetEmbedderField(i, Smi::zero());
}
set_extension(nullptr);
AllocateExternalPointerEntries(GetIsolate());
if (!backing_store) {
set_backing_store(GetIsolate(), nullptr);
set_byte_length(0);
set_max_byte_length(0);
} else {
Attach(std::move(backing_store));
}
if (shared == SharedFlag::kShared) {
GetIsolate()->CountUsage(
v8::Isolate::UseCounterFeature::kSharedArrayBufferConstructed);
}
}
void JSArrayBuffer::Attach(std::shared_ptr<BackingStore> backing_store) {
DCHECK_NOT_NULL(backing_store);
DCHECK_EQ(is_shared(), backing_store->is_shared());
DCHECK_EQ(is_resizable(), backing_store->is_resizable());
DCHECK_IMPLIES(
!backing_store->is_wasm_memory() && !backing_store->is_resizable(),
backing_store->byte_length() == backing_store->max_byte_length());
DCHECK(!was_detached());
Isolate* isolate = GetIsolate();
set_backing_store(isolate, backing_store->buffer_start());
if (is_shared() && is_resizable()) {
// GSABs need to read their byte_length from the BackingStore. Maintain the
// invariant that their byte_length field is always 0.
set_byte_length(0);
} else {
set_byte_length(backing_store->byte_length());
}
set_max_byte_length(backing_store->max_byte_length());
if (backing_store->is_wasm_memory()) set_is_detachable(false);
if (!backing_store->free_on_destruct()) set_is_external(true);
Heap* heap = isolate->heap();
ArrayBufferExtension* extension = EnsureExtension();
size_t bytes = backing_store->PerIsolateAccountingLength();
extension->set_accounting_length(bytes);
extension->set_backing_store(std::move(backing_store));
heap->AppendArrayBufferExtension(*this, extension);
}
void JSArrayBuffer::Detach(bool force_for_wasm_memory) {
if (was_detached()) return;
if (force_for_wasm_memory) {
// Skip the is_detachable() check.
} else if (!is_detachable()) {
// Not detachable, do nothing.
return;
}
Isolate* const isolate = GetIsolate();
ArrayBufferExtension* extension = this->extension();
if (extension) {
DisallowGarbageCollection disallow_gc;
isolate->heap()->DetachArrayBufferExtension(*this, extension);
std::shared_ptr<BackingStore> backing_store = RemoveExtension();
CHECK_IMPLIES(force_for_wasm_memory, backing_store->is_wasm_memory());
}
if (Protectors::IsArrayBufferDetachingIntact(isolate)) {
Protectors::InvalidateArrayBufferDetaching(isolate);
}
DCHECK(!is_shared());
DCHECK(!is_asmjs_memory());
set_backing_store(isolate, nullptr);
set_byte_length(0);
set_was_detached(true);
}
std::shared_ptr<BackingStore> JSArrayBuffer::GetBackingStore() {
if (!extension()) return nullptr;
return extension()->backing_store();
}
ArrayBufferExtension* JSArrayBuffer::EnsureExtension() {
ArrayBufferExtension* extension = this->extension();
if (extension != nullptr) return extension;
extension = new ArrayBufferExtension(std::shared_ptr<BackingStore>());
set_extension(extension);
return extension;
}
std::shared_ptr<BackingStore> JSArrayBuffer::RemoveExtension() {
ArrayBufferExtension* extension = this->extension();
DCHECK_NOT_NULL(extension);
auto result = extension->RemoveBackingStore();
// Remove pointer to extension such that the next GC will free it
// automatically.
set_extension(nullptr);
return result;
}
void JSArrayBuffer::MarkExtension() {
ArrayBufferExtension* extension = this->extension();
if (extension) {
extension->Mark();
}
}
void JSArrayBuffer::YoungMarkExtension() {
ArrayBufferExtension* extension = this->extension();
if (extension) {
extension->YoungMark();
}
}
void JSArrayBuffer::YoungMarkExtensionPromoted() {
ArrayBufferExtension* extension = this->extension();
if (extension) {
extension->YoungMarkPromoted();
}
}
Handle<JSArrayBuffer> JSTypedArray::GetBuffer() {
Isolate* isolate = GetIsolate();
Handle<JSTypedArray> self(*this, isolate);
DCHECK(IsTypedArrayOrRabGsabTypedArrayElementsKind(self->GetElementsKind()));
Handle<JSArrayBuffer> array_buffer(JSArrayBuffer::cast(self->buffer()),
isolate);
if (!is_on_heap()) {
// Already is off heap, so return the existing buffer.
return array_buffer;
}
DCHECK(!array_buffer->is_resizable());
// The existing array buffer should be empty.
DCHECK_NULL(array_buffer->backing_store());
// Allocate a new backing store and attach it to the existing array buffer.
size_t byte_length = self->byte_length();
auto backing_store =
BackingStore::Allocate(isolate, byte_length, SharedFlag::kNotShared,
InitializedFlag::kUninitialized);
if (!backing_store) {
isolate->heap()->FatalProcessOutOfMemory("JSTypedArray::GetBuffer");
}
// Copy the elements into the backing store of the array buffer.
if (byte_length > 0) {
memcpy(backing_store->buffer_start(), self->DataPtr(), byte_length);
}
// Attach the backing store to the array buffer.
array_buffer->Setup(SharedFlag::kNotShared, ResizableFlag::kNotResizable,
std::move(backing_store));
// Clear the elements of the typed array.
self->set_elements(ReadOnlyRoots(isolate).empty_byte_array());
self->SetOffHeapDataPtr(isolate, array_buffer->backing_store(), 0);
DCHECK(!self->is_on_heap());
return array_buffer;
}
// ES#sec-integer-indexed-exotic-objects-defineownproperty-p-desc
// static
Maybe<bool> JSTypedArray::DefineOwnProperty(Isolate* isolate,
Handle<JSTypedArray> o,
Handle<Object> key,
PropertyDescriptor* desc,
Maybe<ShouldThrow> should_throw) {
// 1. Assert: IsPropertyKey(P) is true.
DCHECK(key->IsName() || key->IsNumber());
// 2. Assert: O is an Object that has a [[ViewedArrayBuffer]] internal slot.
// 3. If Type(P) is String, then
PropertyKey lookup_key(isolate, key);
if (lookup_key.is_element() || key->IsSmi() || key->IsString()) {
// 3a. Let numericIndex be ! CanonicalNumericIndexString(P)
// 3b. If numericIndex is not undefined, then
bool is_minus_zero = false;
if (key->IsSmi() || // Smi keys are definitely canonical
CanonicalNumericIndexString(isolate, lookup_key, &is_minus_zero)) {
// 3b i. If IsInteger(numericIndex) is false, return false.
// 3b ii. If numericIndex = -0, return false.
// 3b iii. If numericIndex < 0, return false.
if (!lookup_key.is_element() || is_minus_zero) {
RETURN_FAILURE(isolate, GetShouldThrow(isolate, should_throw),
NewTypeError(MessageTemplate::kInvalidTypedArrayIndex));
}
size_t index = lookup_key.index();
// 3b iv. Let length be O.[[ArrayLength]].
size_t length = o->length();
// 3b v. If numericIndex ≥ length, return false.
if (o->WasDetached() || index >= length) {
RETURN_FAILURE(isolate, GetShouldThrow(isolate, should_throw),
NewTypeError(MessageTemplate::kInvalidTypedArrayIndex));
}
// 3b vi. If IsAccessorDescriptor(Desc) is true, return false.
if (PropertyDescriptor::IsAccessorDescriptor(desc)) {
RETURN_FAILURE(isolate, GetShouldThrow(isolate, should_throw),
NewTypeError(MessageTemplate::kRedefineDisallowed, key));
}
// 3b vii. If Desc has a [[Configurable]] field and if
// Desc.[[Configurable]] is false, return false.
// 3b viii. If Desc has an [[Enumerable]] field and if Desc.[[Enumerable]]
// is false, return false.
// 3b ix. If Desc has a [[Writable]] field and if Desc.[[Writable]] is
// false, return false.
if ((desc->has_configurable() && !desc->configurable()) ||
(desc->has_enumerable() && !desc->enumerable()) ||
(desc->has_writable() && !desc->writable())) {
RETURN_FAILURE(isolate, GetShouldThrow(isolate, should_throw),
NewTypeError(MessageTemplate::kRedefineDisallowed, key));
}
// 3b x. If Desc has a [[Value]] field, then
// 3b x 1. Let value be Desc.[[Value]].
// 3b x 2. Return ? IntegerIndexedElementSet(O, numericIndex, value).
if (desc->has_value()) {
if (!desc->has_configurable()) desc->set_configurable(true);
if (!desc->has_enumerable()) desc->set_enumerable(true);
if (!desc->has_writable()) desc->set_writable(true);
Handle<Object> value = desc->value();
LookupIterator it(isolate, o, index, LookupIterator::OWN);
RETURN_ON_EXCEPTION_VALUE(
isolate,
DefineOwnPropertyIgnoreAttributes(&it, value, desc->ToAttributes()),
Nothing<bool>());
}
// 3b xi. Return true.
return Just(true);
}
}
// 4. Return ! OrdinaryDefineOwnProperty(O, P, Desc).
return OrdinaryDefineOwnProperty(isolate, o, lookup_key, desc, should_throw);
}
ExternalArrayType JSTypedArray::type() {
switch (map().elements_kind()) {
#define ELEMENTS_KIND_TO_ARRAY_TYPE(Type, type, TYPE, ctype) \
case TYPE##_ELEMENTS: \
return kExternal##Type##Array;
TYPED_ARRAYS(ELEMENTS_KIND_TO_ARRAY_TYPE)
RAB_GSAB_TYPED_ARRAYS_WITH_TYPED_ARRAY_TYPE(ELEMENTS_KIND_TO_ARRAY_TYPE)
#undef ELEMENTS_KIND_TO_ARRAY_TYPE
default:
UNREACHABLE();
}
}
size_t JSTypedArray::element_size() const {
switch (map().elements_kind()) {
#define ELEMENTS_KIND_TO_ELEMENT_SIZE(Type, type, TYPE, ctype) \
case TYPE##_ELEMENTS: \
return sizeof(ctype);
TYPED_ARRAYS(ELEMENTS_KIND_TO_ELEMENT_SIZE)
RAB_GSAB_TYPED_ARRAYS(ELEMENTS_KIND_TO_ELEMENT_SIZE)
#undef ELEMENTS_KIND_TO_ELEMENT_SIZE
default:
UNREACHABLE();
}
}
size_t JSTypedArray::LengthTrackingGsabBackedTypedArrayLength(
Isolate* isolate, Address raw_array) {
// TODO(v8:11111): Cache the last seen length in JSArrayBuffer and use it
// in bounds checks to minimize the need for calling this function.
DCHECK(FLAG_harmony_rab_gsab);
DisallowGarbageCollection no_gc;
DisallowJavascriptExecution no_js(isolate);
JSTypedArray array = JSTypedArray::cast(Object(raw_array));
CHECK(array.is_length_tracking());
JSArrayBuffer buffer = array.buffer();
CHECK(buffer.is_resizable());
CHECK(buffer.is_shared());
size_t backing_byte_length =
buffer.GetBackingStore()->byte_length(std::memory_order_seq_cst);
CHECK_GE(backing_byte_length, array.byte_offset());
auto element_byte_size = ElementsKindToByteSize(array.GetElementsKind());
return (backing_byte_length - array.byte_offset()) / element_byte_size;
}
} // namespace internal
} // namespace v8
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