blob: 277ce63f260cd0db1152eddbc60c65ab18eadf97 [file]
// 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.
#ifndef V8_OBJECTS_JS_ARRAY_BUFFER_INL_H_
#define V8_OBJECTS_JS_ARRAY_BUFFER_INL_H_
#include "src/objects/js-array-buffer.h"
// Include the non-inl header before the rest of the headers.
#include "src/heap/heap-write-barrier-inl.h"
#include "src/heap/local-heap.h"
#include "src/objects/heap-object-field-inl.h"
#include "src/objects/heap-object-inl.h"
#include "src/objects/js-objects-inl.h"
#include "src/sandbox/check.h"
#include "src/utils/memcopy.h"
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
namespace v8 {
namespace internal {
//
// JSArrayBuffer.
//
Tagged<MaybeObject> JSArrayBuffer::views_or_detach_key() const {
return views_or_detach_key_.load();
}
void JSArrayBuffer::set_views_or_detach_key(Tagged<MaybeObject> value,
WriteBarrierMode mode) {
views_or_detach_key_.store(this, value, mode);
}
size_t JSArrayBuffer::byte_length() const {
// Use GetByteLength() for growable SharedArrayBuffers.
DCHECK(!is_shared() || !is_resizable_by_js());
return byte_length_unchecked();
}
size_t JSArrayBuffer::byte_length_unchecked() const {
return ReadBoundedSizeField(offsetof(JSArrayBuffer, raw_byte_length_));
}
void JSArrayBuffer::set_byte_length(size_t value) {
WriteBoundedSizeField(offsetof(JSArrayBuffer, raw_byte_length_), value);
}
size_t JSArrayBuffer::max_byte_length() const {
return ReadBoundedSizeField(offsetof(JSArrayBuffer, raw_max_byte_length_));
}
void JSArrayBuffer::set_max_byte_length(size_t value) {
WriteBoundedSizeField(offsetof(JSArrayBuffer, raw_max_byte_length_), value);
}
void* JSArrayBuffer::backing_store() const {
return backing_store(GetPtrComprCageBase(this));
}
void* JSArrayBuffer::backing_store(PtrComprCageBase cage_base) const {
Address value = ReadSandboxedPointerField(
offsetof(JSArrayBuffer, backing_store_), cage_base);
return reinterpret_cast<void*>(value);
}
void JSArrayBuffer::set_backing_store(Isolate* isolate, void* value) {
Address addr = reinterpret_cast<Address>(value);
WriteSandboxedPointerField(offsetof(JSArrayBuffer, backing_store_), isolate,
addr);
}
std::shared_ptr<BackingStore> JSArrayBuffer::GetBackingStore() const {
auto* ext = extension();
return ext == nullptr ? nullptr : ext->backing_store();
}
size_t JSArrayBuffer::GetByteLength() const {
const SharedFlag is_shared_ = is_shared();
const ResizableFlag is_resizable = is_resizable_by_js();
auto* ext = extension();
if (V8_UNLIKELY(is_shared_ && is_resizable)) {
// Invariant: byte_length for GSAB is 0 (it needs to be read from the
// BackingStore). Don't use the byte_length getter, which DCHECKs that it's
// not used on growable SharedArrayBuffers.
DCHECK_EQ(0, byte_length_unchecked());
// The extension might be null if the byte length is read after allocation
// but before the backing store is attached (e.g., during memory
// measurement).
if (ext == nullptr) {
return 0;
}
SBXCHECK(ext->is_shared() && ext->is_resizable_by_js());
return ext->backing_store()->byte_length(std::memory_order_seq_cst);
}
// We should not be reading the JS-visible byte length of a RAB from a
// background thread, unless the mutator is guaranteed to be paused. This
// happens during a GC pause, during teardown, or when the main thread is
// parked.
DCHECK_IMPLIES(
is_resizable && !is_shared_ && LocalHeap::Current() != nullptr &&
!LocalHeap::Current()->is_main_thread(),
LocalHeap::Current()->heap()->IsInGC() ||
LocalHeap::Current()->heap()->IsTearingDown() ||
LocalHeap::Current()->heap()->main_thread_local_heap()->IsParked());
return byte_length();
}
uint32_t JSArrayBuffer::GetBackingStoreRefForDeserialization() const {
return static_cast<uint32_t>(
ReadField<Address>(offsetof(JSArrayBuffer, backing_store_)));
}
void JSArrayBuffer::SetBackingStoreRefForSerialization(uint32_t ref) {
WriteField<Address>(offsetof(JSArrayBuffer, backing_store_),
static_cast<Address>(ref));
}
void JSArrayBuffer::init_extension() {
#if V8_COMPRESS_POINTERS
// The extension field is lazily-initialized, so set it to null initially.
base::AsAtomic32::Relaxed_Store(extension_handle_location(),
kNullExternalPointerHandle);
#else
base::AsAtomicPointer::Relaxed_Store(extension_location(), nullptr);
#endif // V8_COMPRESS_POINTERS
}
ArrayBufferExtension* JSArrayBuffer::extension() const {
#if V8_COMPRESS_POINTERS
Isolate* isolate = Isolate::Current();
ExternalPointerHandle handle =
base::AsAtomic32::Relaxed_Load(extension_handle_location());
return reinterpret_cast<ArrayBufferExtension*>(
isolate->external_pointer_table().Get(handle, kArrayBufferExtensionTag));
#else
return base::AsAtomicPointer::Relaxed_Load(extension_location());
#endif // V8_COMPRESS_POINTERS
}
void JSArrayBuffer::set_extension(ArrayBufferExtension* extension) {
#if V8_COMPRESS_POINTERS
// TODO(saelo): if we ever use the external pointer table for all external
// pointer fields in the no-sandbox-ptr-compression config, replace this code
// here and above with the respective external pointer accessors.
IsolateForPointerCompression isolate = Isolate::Current();
constexpr ExternalPointerTag tag = kArrayBufferExtensionTag;
Address value = reinterpret_cast<Address>(extension);
ExternalPointerTable& table = isolate.GetExternalPointerTableFor(tag);
ExternalPointerHandle current_handle =
base::AsAtomic32::Relaxed_Load(extension_handle_location());
if (current_handle == kNullExternalPointerHandle) {
ExternalPointerHandle handle = table.AllocateAndInitializeEntry(
isolate.GetExternalPointerTableSpaceFor(tag, address()), value, tag);
base::AsAtomic32::Release_Store(extension_handle_location(), handle);
WriteBarrier::ForExternalPointer(this, ExternalPointerSlot(&extension_));
} else {
table.Set(current_handle, value, tag);
}
#else
base::AsAtomicPointer::Relaxed_Store(extension_location(), extension);
#endif // V8_COMPRESS_POINTERS
WriteBarrier::ForArrayBufferExtension(this, extension);
}
ArrayBufferExtension* JSArrayBuffer::extract_extension(
Isolate* isolate,
const DisallowGarbageCollection& disallow_gc V8_LIFETIME_BOUND) {
#if V8_COMPRESS_POINTERS
ExternalPointerHandle handle =
base::AsAtomic32::Relaxed_Load(extension_handle_location());
if (handle == kNullExternalPointerHandle) {
return nullptr;
}
return reinterpret_cast<ArrayBufferExtension*>(
isolate->external_pointer_table().Exchange(handle, kNullAddress,
kArrayBufferExtensionTag));
#else
return base::AsAtomicPointer::Relaxed_Swap(extension_location(), nullptr);
#endif // V8_COMPRESS_POINTERS
}
#if V8_COMPRESS_POINTERS
ExternalPointerHandle* JSArrayBuffer::extension_handle_location() const {
return reinterpret_cast<ExternalPointerHandle*>(extension_.storage_address());
}
#else
ArrayBufferExtension** JSArrayBuffer::extension_location() const {
return reinterpret_cast<ArrayBufferExtension**>(extension_.storage_address());
}
#endif // V8_COMPRESS_POINTERS
void JSArrayBuffer::clear_padding() {
#if TAGGED_SIZE_8_BYTES
static_assert(sizeof(optional_padding_) == 4);
optional_padding_ = 0;
#endif
}
Tagged<MaybeObject> JSArrayBuffer::views() const {
if (has_detach_key()) return kManyViews;
Tagged<MaybeObject> res = views_or_detach_key();
DCHECK(res.IsSmi() || res.IsWeak() || res.IsCleared());
return res;
}
void JSArrayBuffer::set_views(Tagged<MaybeObject> value,
WriteBarrierMode mode) {
DCHECK(!has_detach_key());
DCHECK(value.IsWeak() || value == kNoView || value == kManyViews);
set_views_or_detach_key(value, mode);
}
Tagged<Cell> JSArrayBuffer::detach_key() const {
DCHECK(has_detach_key());
return Cast<Cell>(views_or_detach_key().GetHeapObjectAssumeStrong());
}
void JSArrayBuffer::set_detach_key(Tagged<Cell> value, WriteBarrierMode mode) {
set_views_or_detach_key(value, mode);
}
bool JSArrayBuffer::has_detach_key() const {
Tagged<MaybeObject> value = views_or_detach_key();
return value.IsStrong() && IsCell(value.GetHeapObjectAssumeStrong());
}
Tagged<Object> JSArrayBuffer::DetachKey(Isolate* isolate) {
if (!has_detach_key()) {
return ReadOnlyRoots(isolate).undefined_value();
}
return detach_key()->value();
}
inline void JSArrayBuffer::AttachView(Tagged<JSArrayBufferView> new_view) {
if (!v8_flags.track_array_buffer_views) return;
if (is_shared() || has_detach_key()) return;
Tagged<MaybeObject> current_views = views();
if (current_views == kManyViews) return;
if (current_views.IsCleared() || current_views == kNoView) {
set_views(MakeWeak(new_view));
return;
}
DCHECK(IsJSArrayBufferView(current_views.GetHeapObjectAssumeWeak()));
set_views(kManyViews);
}
void JSArrayBuffer::set_bit_field(uint32_t bits) {
base::AsAtomic32::Relaxed_Store(&bit_field_, bits);
}
uint32_t JSArrayBuffer::bit_field() const {
return base::AsAtomic32::Relaxed_Load(&bit_field_);
}
// |bit_field| fields.
BIT_FIELD_ACCESSORS(JSArrayBuffer, bit_field, is_external,
JSArrayBuffer::IsExternalBit)
BIT_FIELD_ACCESSORS(JSArrayBuffer, bit_field, is_detachable,
JSArrayBuffer::IsDetachableBit)
BIT_FIELD_ACCESSORS(JSArrayBuffer, bit_field, was_detached,
JSArrayBuffer::WasDetachedBit)
SharedFlag JSArrayBuffer::is_shared() const {
return IsSharedBit::decode(bit_field());
}
void JSArrayBuffer::set_is_shared(SharedFlag value) {
set_bit_field(IsSharedBit::update(bit_field(), value));
}
ResizableFlag JSArrayBuffer::is_resizable_by_js() const {
return IsResizableByJsBit::decode(bit_field());
}
void JSArrayBuffer::set_is_resizable_by_js(ResizableFlag value) {
set_bit_field(IsResizableByJsBit::update(bit_field(), value));
if (ArrayBufferExtension* extension = this->extension()) {
extension->set_is_resizable_by_js(value);
}
}
bool JSArrayBuffer::is_immutable() const {
return IsImmutableBit::decode(bit_field()).value();
}
void JSArrayBuffer::set_is_immutable(ImmutableFlag value) {
set_bit_field(IsImmutableBit::update(bit_field(), value));
}
bool JSArrayBuffer::was_detached(AcquireLoadTag) const {
uint32_t bits = base::AsAtomic32::Acquire_Load(&bit_field_);
return WasDetachedBit::decode(bits);
}
void JSArrayBuffer::set_was_detached(bool value, ReleaseStoreTag) {
uint32_t bits = bit_field();
bits = WasDetachedBit::update(bits, value);
base::AsAtomic32::Release_Store(&bit_field_, bits);
}
bool JSArrayBuffer::IsEmpty() const {
auto backing_store = GetBackingStore();
bool is_empty = !backing_store || backing_store->IsEmpty();
DCHECK_IMPLIES(is_empty, byte_length() == 0);
return is_empty;
}
//
// JSArrayBufferView.
//
Tagged<JSArrayBuffer> JSArrayBufferView::buffer() const {
return buffer_.load();
}
void JSArrayBufferView::set_buffer(Tagged<JSArrayBuffer> value,
WriteBarrierMode mode) {
buffer_.store(this, value, mode);
}
uint32_t JSArrayBufferView::bit_field() const {
return base::AsAtomic32::Relaxed_Load(&bit_field_);
}
void JSArrayBufferView::set_bit_field(uint32_t value) {
base::AsAtomic32::Relaxed_Store(&bit_field_, value);
}
size_t JSArrayBufferView::byte_offset() const {
return ReadBoundedSizeField(offsetof(JSArrayBufferView, raw_byte_offset_));
}
void JSArrayBufferView::set_byte_offset(size_t value) {
WriteBoundedSizeField(offsetof(JSArrayBufferView, raw_byte_offset_), value);
}
size_t JSArrayBufferView::byte_length() const {
return ReadBoundedSizeField(offsetof(JSArrayBufferView, raw_byte_length_));
}
void JSArrayBufferView::set_byte_length(size_t value) {
WriteBoundedSizeField(offsetof(JSArrayBufferView, raw_byte_length_), value);
}
bool JSArrayBufferView::WasDetached() const { return buffer()->was_detached(); }
bool JSArrayBufferView::IsDetachedOrOutOfBounds() const {
Tagged<JSArrayBuffer> backing_buffer = buffer();
if (backing_buffer->was_detached()) {
return true;
}
if (!is_backed_by_rab()) {
// TypedArrays backed by GSABs or regular AB/SABs are never out of bounds.
// This shortcut is load-bearing; this enables determining
// IsDetachedOrOutOfBounds without consulting the BackingStore.
return false;
}
size_t buffer_byte_length =
backing_buffer->GetBackingStore()->byte_length();
// Length-tracking ArrayBufferViews have byte_length() == 0, so this math
// works.
return byte_offset() + byte_length() > buffer_byte_length;
}
BIT_FIELD_ACCESSORS(JSArrayBufferView, bit_field, is_length_tracking,
JSArrayBufferView::IsLengthTrackingBit)
BIT_FIELD_ACCESSORS(JSArrayBufferView, bit_field, is_backed_by_rab,
JSArrayBufferView::IsBackedByRabBit)
bool JSArrayBufferView::IsVariableLength() const {
return is_length_tracking() || is_backed_by_rab();
}
//
// JSTypedArray.
//
// static
constexpr std::pair<ExternalArrayType, size_t>
JSTypedArray::TypeAndElementSizeFor(ElementsKind kind) {
switch (kind) {
#define ELEMENTS_KIND_TO_ARRAY_TYPE(Type, type, TYPE, ctype) \
case TYPE##_ELEMENTS: \
return {kExternal##Type##Array, sizeof(ctype)};
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::length() const {
return ReadBoundedSizeField(offsetof(JSTypedArray, raw_length_));
}
void JSTypedArray::set_length(size_t value) {
WriteBoundedSizeField(offsetof(JSTypedArray, raw_length_), value);
}
Tagged<Object> JSTypedArray::base_pointer() const {
return base_pointer_.load();
}
Tagged<Object> JSTypedArray::base_pointer(AcquireLoadTag) const {
return base_pointer_.Acquire_Load();
}
void JSTypedArray::set_base_pointer(Tagged<Object> value,
WriteBarrierMode mode) {
base_pointer_.store(this, value, mode);
}
void JSTypedArray::set_base_pointer(Tagged<Object> value, ReleaseStoreTag,
WriteBarrierMode mode) {
base_pointer_.Release_Store(this, value, mode);
}
Address JSTypedArray::external_pointer() const {
return external_pointer(GetPtrComprCageBase(this));
}
Address JSTypedArray::external_pointer(PtrComprCageBase cage_base) const {
return ReadSandboxedPointerField(offsetof(JSTypedArray, external_pointer_),
cage_base);
}
void JSTypedArray::set_external_pointer(Isolate* isolate, Address value) {
WriteSandboxedPointerField(offsetof(JSTypedArray, external_pointer_), isolate,
value);
}
size_t JSTypedArray::GetLengthOrOutOfBounds(bool& out_of_bounds) const {
DCHECK(!out_of_bounds);
if (WasDetached()) return 0;
if (IsVariableLength()) {
return GetVariableLengthOrOutOfBounds(out_of_bounds);
}
return byte_length() / element_size();
}
size_t JSTypedArray::GetLength() const {
bool out_of_bounds = false;
return GetLengthOrOutOfBounds(out_of_bounds);
}
size_t JSTypedArray::GetByteLength() const {
if (WasDetached()) return 0;
if (IsVariableLength()) {
bool out_of_bounds = false;
return GetVariableByteLengthOrOutOfBounds(out_of_bounds);
}
return byte_length();
}
bool JSTypedArray::IsOutOfBounds() const {
bool out_of_bounds = false;
GetLengthOrOutOfBounds(out_of_bounds);
return out_of_bounds;
}
// static
inline void JSTypedArray::ForFixedTypedArray(ExternalArrayType array_type,
size_t* element_size,
ElementsKind* element_kind) {
switch (array_type) {
#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype) \
case kExternal##Type##Array: \
*element_size = sizeof(ctype); \
*element_kind = TYPE##_ELEMENTS; \
return;
TYPED_ARRAYS(TYPED_ARRAY_CASE)
#undef TYPED_ARRAY_CASE
}
UNREACHABLE();
}
Address JSTypedArray::ExternalPointerCompensationForOnHeapArray(
PtrComprCageBase cage_base) {
#ifdef V8_COMPRESS_POINTERS
return cage_base.address();
#else
return 0;
#endif
}
uint32_t JSTypedArray::GetExternalBackingStoreRefForDeserialization() const {
DCHECK(!is_on_heap());
return static_cast<uint32_t>(
ReadField<Address>(offsetof(JSTypedArray, external_pointer_)));
}
void JSTypedArray::SetExternalBackingStoreRefForSerialization(uint32_t ref) {
DCHECK(!is_on_heap());
WriteField<Address>(offsetof(JSTypedArray, external_pointer_),
static_cast<Address>(ref));
}
void JSTypedArray::RemoveExternalPointerCompensationForSerialization(
Isolate* isolate) {
DCHECK(is_on_heap());
Address offset =
external_pointer() - ExternalPointerCompensationForOnHeapArray(isolate);
WriteField<Address>(offsetof(JSTypedArray, external_pointer_), offset);
}
void JSTypedArray::AddExternalPointerCompensationForDeserialization(
Isolate* isolate) {
DCHECK(is_on_heap());
Address pointer =
ReadField<Address>(offsetof(JSTypedArray, external_pointer_)) +
ExternalPointerCompensationForOnHeapArray(isolate);
set_external_pointer(isolate, pointer);
}
void* JSTypedArray::DataPtr() {
// Zero-extend Tagged_t to Address according to current compression scheme
// so that the addition with |external_pointer| (which already contains
// compensated offset value) will decompress the tagged value.
// See JSTypedArray::ExternalPointerCompensationForOnHeapArray() for details.
static_assert(kOffHeapDataPtrEqualsExternalPointer);
return reinterpret_cast<void*>(external_pointer() +
static_cast<Tagged_t>(base_pointer().ptr()));
}
void JSTypedArray::SetOffHeapDataPtr(Isolate* isolate, void* base,
Address offset) {
Address address = reinterpret_cast<Address>(base) + offset;
set_external_pointer(isolate, address);
// This is the only spot in which the `base_pointer` field can be mutated
// after object initialization. Note this can happen at most once, when
// `JSTypedArray::GetBuffer` transitions from an on- to off-heap
// representation.
// To play well with Turbofan concurrency requirements, `base_pointer` is set
// with a release store, after external_pointer has been set.
set_base_pointer(Smi::zero(), kReleaseStore, SKIP_WRITE_BARRIER);
DCHECK_EQ(address, reinterpret_cast<Address>(DataPtr()));
}
bool JSTypedArray::is_on_heap() const {
// Keep synced with `is_on_heap(AcquireLoadTag)`.
DisallowGarbageCollection no_gc;
return base_pointer() != Smi::zero();
}
bool JSTypedArray::is_on_heap(AcquireLoadTag tag) const {
// Keep synced with `is_on_heap()`.
// Note: For Turbofan concurrency requirements, it's important that this
// function reads only `base_pointer`.
DisallowGarbageCollection no_gc;
return base_pointer(tag) != Smi::zero();
}
// static
MaybeDirectHandle<JSTypedArray> JSTypedArray::Validate(
Isolate* isolate, DirectHandle<Object> receiver, const char* method_name,
TypedArrayAccessMode access_mode) {
if (V8_UNLIKELY(!IsJSTypedArray(*receiver))) {
const MessageTemplate message = MessageTemplate::kNotTypedArray;
THROW_NEW_ERROR(isolate, NewTypeError(message));
}
// All errors throw the same message. In theory we could be more specific
// here. However, many of the fast-paths do not distinguish and we'd rather be
// consistent.
const MessageTemplate message =
access_mode == TypedArrayAccessMode::kWrite
? MessageTemplate::kTypedArrayValidateWriteErrorOperation
: MessageTemplate::kTypedArrayValidateErrorOperation;
DirectHandle<JSTypedArray> array = Cast<JSTypedArray>(receiver);
if (V8_UNLIKELY(array->WasDetached())) {
DirectHandle<String> operation =
isolate->factory()->NewStringFromAsciiChecked(method_name);
THROW_NEW_ERROR(isolate, NewTypeError(message, operation));
}
if (access_mode == TypedArrayAccessMode::kWrite &&
Cast<JSArrayBuffer>(array->buffer())->is_immutable()) {
THROW_NEW_ERROR(
isolate,
NewTypeError(message, isolate->factory()->NewStringFromAsciiChecked(
method_name)));
}
if (V8_UNLIKELY(array->IsVariableLength() && array->IsOutOfBounds())) {
DirectHandle<String> operation =
isolate->factory()->NewStringFromAsciiChecked(method_name);
THROW_NEW_ERROR(isolate, NewTypeError(message, operation));
}
// spec describes to return `buffer`, but it may disrupt current
// implementations, and it's much useful to return array for now.
return array;
}
//
// JSDataViewOrRabGsabDataView.
//
void* JSDataViewOrRabGsabDataView::data_pointer() const {
return data_pointer(GetPtrComprCageBase(this));
}
void* JSDataViewOrRabGsabDataView::data_pointer(
PtrComprCageBase cage_base) const {
Address value = ReadSandboxedPointerField(
offsetof(JSDataViewOrRabGsabDataView, data_pointer_), cage_base);
return reinterpret_cast<void*>(value);
}
void JSDataViewOrRabGsabDataView::set_data_pointer(Isolate* isolate,
void* ptr) {
Address value = reinterpret_cast<Address>(ptr);
WriteSandboxedPointerField(
offsetof(JSDataViewOrRabGsabDataView, data_pointer_), isolate, value);
}
size_t JSRabGsabDataView::GetByteLength() const {
if (IsOutOfBounds()) {
return 0;
}
if (is_length_tracking()) {
// Invariant: byte_length of length tracking DataViews is 0.
DCHECK_EQ(0, byte_length());
return buffer()->GetByteLength() - byte_offset();
}
return byte_length();
}
bool JSRabGsabDataView::IsOutOfBounds() const {
if (!is_backed_by_rab()) {
return false;
}
if (is_length_tracking()) {
return byte_offset() > buffer()->GetByteLength();
}
return byte_offset() + byte_length() > buffer()->GetByteLength();
}
} // namespace internal
} // namespace v8
#include "src/objects/object-macros-undef.h"
#endif // V8_OBJECTS_JS_ARRAY_BUFFER_INL_H_