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chromium/v8/v8.git/main/./src/objects/js-objects-inl.h
blob: c715995c87ffe64746323d3ee48b5c73dd54c221 [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_OBJECTS_INL_H_
#define V8_OBJECTS_JS_OBJECTS_INL_H_
#include "src/objects/js-objects.h"
// Include the non-inl header before the rest of the headers.
#include <optional>
#include "src/common/globals.h"
#include "src/heap/heap-layout-inl.h"
#include "src/heap/heap-write-barrier.h"
#include "src/objects/cpp-heap-external-object.h"
#include "src/objects/cpp-heap-object-wrapper.h"
#include "src/objects/dictionary.h"
#include "src/objects/elements.h"
#include "src/objects/embedder-data-slot-inl.h"
#include "src/objects/feedback-vector.h"
#include "src/objects/field-index-inl.h"
#include "src/objects/fixed-array-base.h"
#include "src/objects/fixed-array.h"
#include "src/objects/fixed-primitive-array.h"
#include "src/objects/hash-table-inl.h"
#include "src/objects/heap-number-inl.h"
#include "src/objects/heap-object-field-inl.h"
#include "src/objects/heap-object-inl.h"
#include "src/objects/heap-object.h"
#include "src/objects/instance-type-inl.h"
#include "src/objects/js-interceptor-map-inl.h"
#include "src/objects/keys.h"
#include "src/objects/lookup-inl.h"
#include "src/objects/primitive-heap-object.h"
#include "src/objects/property-array-inl.h"
#include "src/objects/prototype-inl.h"
#include "src/objects/shared-function-info.h"
#include "src/objects/slots.h"
#include "src/objects/smi-inl.h"
#include "src/objects/string.h"
#include "src/objects/swiss-name-dictionary-inl.h"
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
namespace v8::internal {
Tagged<FixedArrayBase> JSObject::elements() const { return elements_.load(); }
Tagged<FixedArrayBase> JSObject::elements(RelaxedLoadTag) const {
return elements_.Relaxed_Load();
}
void JSObject::set_elements(Tagged<FixedArrayBase> value,
WriteBarrierMode mode) {
elements_.Relaxed_Store(this, value, mode);
}
MaybeHandle<Object> JSReceiver::GetProperty(Isolate* isolate,
DirectHandle<JSReceiver> receiver,
DirectHandle<Name> name) {
LookupIterator it(isolate, receiver, name, receiver);
if (!it.IsFound()) return it.factory()->undefined_value();
return Object::GetProperty(&it);
}
MaybeHandle<Object> JSReceiver::GetElement(Isolate* isolate,
DirectHandle<JSReceiver> receiver,
uint32_t index) {
LookupIterator it(isolate, receiver, index, receiver);
if (!it.IsFound()) return it.factory()->undefined_value();
return Object::GetProperty(&it);
}
Handle<Object> JSReceiver::GetDataProperty(Isolate* isolate,
DirectHandle<JSReceiver> object,
DirectHandle<Name> name,
AllowAllocation allow_allocation) {
LookupIterator it(isolate, object, name, object,
LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
if (!it.IsFound()) return it.factory()->undefined_value();
return GetDataProperty(&it, allow_allocation);
}
MaybeDirectHandle<JSPrototype> JSReceiver::GetPrototype(
Isolate* isolate, DirectHandle<JSReceiver> receiver) {
// We don't expect access checks to be needed on JSProxy objects.
DCHECK(!IsAccessCheckNeeded(*receiver) || IsJSObject(*receiver));
PrototypeIterator iter(isolate, receiver, kStartAtReceiver,
PrototypeIterator::END_AT_NON_HIDDEN);
do {
if (!iter.AdvanceFollowingProxies()) return {};
} while (!iter.IsAtEnd());
return PrototypeIterator::GetCurrent(iter);
}
MaybeHandle<Object> JSReceiver::GetProperty(Isolate* isolate,
DirectHandle<JSReceiver> receiver,
const char* name) {
DirectHandle<String> str = isolate->factory()->InternalizeUtf8String(name);
return GetProperty(isolate, receiver, str);
}
// static
V8_WARN_UNUSED_RESULT MaybeDirectHandle<FixedArray> JSReceiver::OwnPropertyKeys(
Isolate* isolate, DirectHandle<JSReceiver> object) {
return KeyAccumulator::GetKeys(isolate, object, KeyCollectionMode::kOwnOnly,
ALL_PROPERTIES,
GetKeysConversion::kConvertToString);
}
bool JSObject::PrototypeHasNoElements(Isolate* isolate,
Tagged<JSObject> object) {
DisallowGarbageCollection no_gc;
Tagged<HeapObject> prototype = Cast<HeapObject>(object->map()->prototype());
ReadOnlyRoots roots(isolate);
Tagged<HeapObject> null = roots.null_value();
Tagged<FixedArrayBase> empty_fixed_array = roots.empty_fixed_array();
Tagged<FixedArrayBase> empty_slow_element_dictionary =
roots.empty_slow_element_dictionary();
while (prototype != null) {
Tagged<Map> map = prototype->map();
if (IsCustomElementsReceiverMap(map)) return false;
Tagged<FixedArrayBase> elements = Cast<JSObject>(prototype)->elements();
if (elements != empty_fixed_array &&
elements != empty_slow_element_dictionary) {
return false;
}
prototype = Cast<HeapObject>(map->prototype());
}
return true;
}
Tagged<JSReceiver::PropertiesOrHash> JSReceiver::raw_properties_or_hash()
const {
return properties_or_hash_.load();
}
void JSReceiver::set_raw_properties_or_hash(Tagged<PropertiesOrHash> value,
WriteBarrierMode mode) {
properties_or_hash_.store(this, value, mode);
}
Tagged<JSReceiver::PropertiesOrHash> JSReceiver::raw_properties_or_hash(
RelaxedLoadTag tag) const {
return properties_or_hash_.Relaxed_Load();
}
void JSReceiver::set_raw_properties_or_hash(Tagged<PropertiesOrHash> value,
RelaxedStoreTag,
WriteBarrierMode mode) {
properties_or_hash_.Relaxed_Store(this, value, mode);
}
void JSObject::EnsureCanContainHeapObjectElements(
Isolate* isolate, DirectHandle<JSObject> object) {
JSObject::ValidateElements(isolate, *object);
ElementsKind elements_kind = object->map()->elements_kind();
if (!IsObjectElementsKind(elements_kind)) {
if (IsHoleyElementsKind(elements_kind)) {
TransitionElementsKind(isolate, object, HOLEY_ELEMENTS);
} else {
TransitionElementsKind(isolate, object, PACKED_ELEMENTS);
}
}
}
template <typename TSlot>
ElementsKind JSObject::GetTransitionedElementsKind(Isolate* isolate,
ElementsKind current_kind,
TSlot elements,
uint32_t count,
EnsureElementsMode mode) {
static_assert(std::is_same_v<TSlot, FullObjectSlot> ||
std::is_same_v<TSlot, ObjectSlot>,
"Only ObjectSlot and FullObjectSlot are expected here");
DisallowGarbageCollection no_gc;
if (current_kind == HOLEY_ELEMENTS) return current_kind;
ElementsKind target_kind = current_kind;
DCHECK(mode != ALLOW_COPIED_DOUBLE_ELEMENTS);
bool is_holey = IsHoleyElementsKind(current_kind);
Tagged<Object> the_hole = GetReadOnlyRoots().the_hole_value();
TSlot end = elements + count;
for (; elements < end; ++elements) {
Tagged<Object> current = *elements;
if (current == the_hole) {
is_holey = true;
target_kind = GetHoleyElementsKind(target_kind);
#ifdef V8_ENABLE_UNDEFINED_DOUBLE
} else if (IsUndefined(current)) {
if (mode == ALLOW_CONVERTED_DOUBLE_ELEMENTS) {
if (IsSmiElementsKind(target_kind)) {
target_kind = HOLEY_DOUBLE_ELEMENTS;
} else if (target_kind == PACKED_DOUBLE_ELEMENTS) {
target_kind = HOLEY_DOUBLE_ELEMENTS;
} else {
DCHECK(target_kind == PACKED_ELEMENTS ||
target_kind == HOLEY_ELEMENTS ||
target_kind == HOLEY_DOUBLE_ELEMENTS);
}
} else if (is_holey) {
if (IsSmiElementsKind(target_kind)) {
return HOLEY_ELEMENTS;
}
} else {
target_kind = PACKED_ELEMENTS;
}
#endif // V8_ENABLE_UNDEFINED_DOUBLE
} else if (!IsSmi(current)) {
if (mode == ALLOW_CONVERTED_DOUBLE_ELEMENTS && IsNumber(current)) {
if (IsSmiElementsKind(target_kind)) {
if (is_holey) {
target_kind = HOLEY_DOUBLE_ELEMENTS;
} else {
target_kind = PACKED_DOUBLE_ELEMENTS;
}
}
} else if (is_holey) {
return HOLEY_ELEMENTS;
} else {
target_kind = PACKED_ELEMENTS;
}
}
}
return target_kind;
}
template <typename TSlot>
void JSObject::EnsureCanContainElements(Isolate* isolate,
DirectHandle<JSObject> object,
TSlot objects, uint32_t count,
EnsureElementsMode mode) {
static_assert(std::is_same_v<TSlot, FullObjectSlot> ||
std::is_same_v<TSlot, ObjectSlot>,
"Only ObjectSlot and FullObjectSlot are expected here");
ElementsKind current_kind = object->GetElementsKind();
ElementsKind target_kind =
GetTransitionedElementsKind(isolate, current_kind, objects, count, mode);
if (target_kind != current_kind) {
TransitionElementsKind(isolate, object, target_kind);
}
}
void JSObject::EnsureCanContainElements(Isolate* isolate,
DirectHandle<JSObject> object,
DirectHandle<FixedArrayBase> elements,
uint32_t length,
EnsureElementsMode mode) {
ReadOnlyRoots roots = GetReadOnlyRoots();
if (elements->map() != roots.fixed_double_array_map()) {
DCHECK(elements->map() == roots.fixed_array_map() ||
elements->map() == roots.fixed_cow_array_map());
if (mode == ALLOW_COPIED_DOUBLE_ELEMENTS) {
mode = DONT_ALLOW_DOUBLE_ELEMENTS;
}
ObjectSlot objects = Cast<FixedArray>(elements)->RawFieldOfFirstElement();
EnsureCanContainElements(isolate, object, objects, length, mode);
return;
}
DCHECK(mode == ALLOW_COPIED_DOUBLE_ELEMENTS);
if (object->GetElementsKind() == HOLEY_SMI_ELEMENTS) {
TransitionElementsKind(isolate, object, HOLEY_DOUBLE_ELEMENTS);
} else if (object->GetElementsKind() == PACKED_SMI_ELEMENTS) {
auto double_array = Cast<FixedDoubleArray>(elements);
for (uint32_t i = 0; i < length; ++i) {
if (double_array->is_the_hole(i)) {
TransitionElementsKind(isolate, object, HOLEY_DOUBLE_ELEMENTS);
return;
}
}
TransitionElementsKind(isolate, object, PACKED_DOUBLE_ELEMENTS);
}
}
void JSObject::SetMapAndElements(Isolate* isolate,
DirectHandle<JSObject> object,
DirectHandle<Map> new_map,
DirectHandle<FixedArrayBase> value) {
JSObject::MigrateToMap(isolate, object, new_map);
DCHECK((object->map()->has_fast_smi_or_object_elements() ||
(*value == ReadOnlyRoots(isolate).empty_fixed_array()) ||
object->map()->has_fast_string_wrapper_elements()) ==
(value->map() == ReadOnlyRoots(isolate).fixed_array_map() ||
value->map() == ReadOnlyRoots(isolate).fixed_cow_array_map()));
DCHECK((*value == ReadOnlyRoots(isolate).empty_fixed_array()) ||
(object->map()->has_fast_double_elements() ==
IsFixedDoubleArray(*value)));
object->set_elements(*value);
}
void JSObject::initialize_elements() {
Tagged<FixedArrayBase> elements = map()->GetInitialElements();
set_elements(elements, SKIP_WRITE_BARRIER);
}
DEF_GETTER(JSObject, GetIndexedInterceptor, Tagged<InterceptorInfo>) {
return map()->GetIndexedInterceptor();
}
DEF_GETTER(JSObject, GetNamedInterceptor, Tagged<InterceptorInfo>) {
return map()->GetNamedInterceptor();
}
// static
int JSObject::GetHeaderSize(Tagged<Map> map) {
// Check for the most common kind of JavaScript object before
// falling into the generic switch. This speeds up the internal
// field operations considerably on average.
InstanceType instance_type = map->instance_type();
return instance_type == JS_OBJECT_TYPE ? JSObject::kHeaderSize
: GetHeaderSize(instance_type);
}
// static
int JSObject::GetEmbedderFieldsStartOffset(Tagged<Map> map) {
// Embedder fields are located after the object header.
return GetHeaderSize(map);
}
int JSObject::GetEmbedderFieldsStartOffset() {
return GetEmbedderFieldsStartOffset(map());
}
// static
bool JSObject::MayHaveEmbedderFields(Tagged<Map> map) {
InstanceType instance_type = map->instance_type();
// TODO(v8) It'd be nice if all objects with embedder data slots inherited
// from JSObjectJSAPIObjectWithEmbedderSlotsWithEmbedderSlots, but this is
// currently not possible due to instance_type constraints.
return InstanceTypeChecker::IsJSObjectWithEmbedderSlots(instance_type) ||
InstanceTypeChecker::IsJSAPIObjectWithEmbedderSlots(instance_type) ||
InstanceTypeChecker::IsJSSpecialObject(instance_type);
}
bool JSObject::MayHaveEmbedderFields() const {
return MayHaveEmbedderFields(map());
}
// static
int JSObject::GetEmbedderFieldCount(Tagged<Map> map) {
// We inline some code from Map::instance_size and Map::GetInObjectProperties
// here, to avoid reading the map's instance size field twice.
// See https://crbug.com/355120682.
int instance_size_in_words = map->instance_size_in_words();
int instance_size = instance_size_in_words << kTaggedSizeLog2;
if (instance_size == kVariableSizeSentinel) return 0;
// Embedder fields are located after the object header, whereas in-object
// properties are located at the end of the object. We don't have to round up
// the header size here because division by kEmbedderDataSlotSizeInTaggedSlots
// will swallow potential padding in case of (kTaggedSize !=
// kSystemPointerSize) anyway.
int in_object_properties =
instance_size_in_words - map->GetInObjectPropertiesStartInWords();
return (((instance_size - GetEmbedderFieldsStartOffset(map)) >>
kTaggedSizeLog2) -
in_object_properties) /
kEmbedderDataSlotSizeInTaggedSlots;
}
int JSObject::GetEmbedderFieldCount() const {
return GetEmbedderFieldCount(map());
}
int JSObject::GetEmbedderFieldOffset(int index) {
DCHECK_LT(static_cast<unsigned>(index),
static_cast<unsigned>(GetEmbedderFieldCount()));
return GetEmbedderFieldsStartOffset() + (kEmbedderDataSlotSize * index);
}
Tagged<Object> JSObject::GetEmbedderField(int index) {
return EmbedderDataSlot(this, index).load_tagged();
}
void JSObject::SetEmbedderField(int index, Tagged<Object> value) {
EmbedderDataSlot::store_tagged(this, index, value);
}
void JSObject::SetEmbedderField(int index, Tagged<Smi> value) {
EmbedderDataSlot(this, index).store_smi(value);
}
// static
bool JSObject::IsDroppableApiObject(const Tagged<Map> map) {
auto instance_type = map->instance_type();
return InstanceTypeChecker::IsJSApiObject(instance_type) ||
instance_type == JS_SPECIAL_API_OBJECT_TYPE;
}
bool JSObject::IsDroppableApiObject() const {
return IsDroppableApiObject(map());
}
// Access fast-case object properties at index. The use of these routines
// is needed to correctly distinguish between properties stored in-object and
// properties stored in the properties array.
// Type system violation: the declared return type Tagged<JSAny> is incorrect.
// Property slots can also hold non-JSAny values such as the Hole sentinel
// (`uninitialized_value` during MigrateFastToFast) and class metadata Structs
// (e.g. ClassPositions, AccessorPair, AccessorInfo). The legacy code
// reinterpret-loaded the slot as JSAny without validation; callers dispatch
// on the descriptor's PropertyKind to know what they actually got.
// TODO(jgruber): Change this to return
// Tagged<UnionOf<JSAny, Hole, ClassPositions, AccessorPair, AccessorInfo>>
// (or Tagged<Object>) and update the ~50 callers to Cast<JSAny> (or
// whatever narrower type they actually expect) at the use site.
Tagged<JSAny> JSObject::RawFastPropertyAt(FieldIndex index) const {
if (index.is_inobject()) {
return TaggedField<JSAny>::Relaxed_Load(this, index.offset());
} else {
return UncheckedCast<JSAny>(
property_array()->get(index.outobject_array_index()));
}
}
// The SeqCst versions of RawFastPropertyAt are used for atomically accessing
// shared struct fields.
// See the TODO(jgruber) on the non-SeqCst overload above.
Tagged<JSAny> JSObject::RawFastPropertyAt(FieldIndex index,
SeqCstAccessTag tag) const {
if (index.is_inobject()) {
return TaggedField<JSAny>::SeqCst_Load(this, index.offset());
} else {
return UncheckedCast<JSAny>(
property_array()->get(index.outobject_array_index(), tag));
}
}
std::optional<Tagged<Object>> JSObject::RawInobjectPropertyAt(
Tagged<Map> original_map, FieldIndex index) const {
CHECK(index.is_inobject());
// This method implements a "snapshot" protocol to protect against reading out
// of bounds of an object. It's used to access a fast in-object property from
// a background thread with no locking. That caller does have the guarantee
// that a garbage collection cannot happen during its query. However, it must
// contend with the main thread altering the object in heavy ways through
// object migration. Specifically, the object can get smaller. Initially, this
// may seem benign, because object migration fills the freed-up space with
// FillerMap words which, even though they offer wrong values, are at
// least tagged values.
// However, there is an additional danger. Sweeper threads may discover the
// filler words and offer that space to the main thread for allocation. Should
// a HeapNumber be allocated into that space while we're reading a property at
// that location (from our out-of-date information), we risk interpreting a
// double value as a pointer. This must be prevented.
//
// We do this by:
//
// a) Reading the map first
// b) Reading the property with acquire semantics (but do not inspect it!)
// c) Re-read the map with acquire semantics.
//
// Only if the maps match can the property be inspected. It may have a "wrong"
// value, but it will be within the bounds of the objects instance size as
// given by the map and it will be a valid Smi or object pointer.
Tagged<Object> maybe_tagged_object =
TaggedField<Object>::Acquire_Load(this, index.offset());
if (original_map != map(kAcquireLoad)) return {};
return maybe_tagged_object;
}
void JSObject::RawFastInobjectPropertyAtPut(FieldIndex index,
Tagged<Object> value,
WriteBarrierMode mode) {
DCHECK(index.is_inobject());
int offset = index.offset();
RELAXED_WRITE_FIELD(this, offset, value);
CONDITIONAL_WRITE_BARRIER(this, offset, value, mode);
}
void JSObject::RawFastInobjectPropertyAtPut(FieldIndex index,
Tagged<Object> value,
SeqCstAccessTag tag) {
DCHECK(index.is_inobject());
DCHECK(IsShared(value));
SEQ_CST_WRITE_FIELD(this, index.offset(), value);
CONDITIONAL_WRITE_BARRIER(this, index.offset(), value, UPDATE_WRITE_BARRIER);
}
void JSObject::FastPropertyAtPut(FieldIndex index, Tagged<Object> value,
WriteBarrierMode mode) {
if (index.is_inobject()) {
RawFastInobjectPropertyAtPut(index, value, mode);
} else {
DCHECK_EQ(UPDATE_WRITE_BARRIER, mode);
property_array()->set(index.outobject_array_index(), value);
}
}
void JSObject::FastPropertyAtPut(FieldIndex index, Tagged<Object> value,
SeqCstAccessTag tag) {
if (index.is_inobject()) {
RawFastInobjectPropertyAtPut(index, value, tag);
} else {
property_array()->set(index.outobject_array_index(), value, tag);
}
}
void JSObject::WriteToField(InternalIndex descriptor, PropertyDetails details,
Tagged<Object> value) {
DCHECK_EQ(PropertyLocation::kField, details.location());
DCHECK_EQ(PropertyKind::kData, details.kind());
DisallowGarbageCollection no_gc;
FieldIndex index = FieldIndex::ForDetails(map(), details);
if (details.representation().IsDouble()) {
// Manipulating the signaling NaN used for the hole and uninitialized
// double field sentinel in C++, e.g. with base::bit_cast or
// value()/set_value(), will change its value on ia32 (the x87 stack is used
// to return values and stores to the stack silently clear the signalling
// bit).
uint64_t bits;
if (IsSmi(value)) {
bits = base::bit_cast<uint64_t>(static_cast<double>(Smi::ToInt(value)));
} else if (IsUninitializedHole(value)) {
bits = kHoleNanInt64;
} else {
DCHECK(IsHeapNumber(value));
bits = Cast<HeapNumber>(value)->value_as_bits();
}
auto box = Cast<HeapNumber>(RawFastPropertyAt(index));
box->set_value_as_bits(bits);
} else {
FastPropertyAtPut(index, value);
}
}
Tagged<Object> JSObject::RawFastInobjectPropertyAtSwap(FieldIndex index,
Tagged<Object> value,
SeqCstAccessTag tag) {
DCHECK(index.is_inobject());
DCHECK(IsShared(value));
int offset = index.offset();
Tagged<Object> old_value = SEQ_CST_SWAP_FIELD(this, offset, value);
CONDITIONAL_WRITE_BARRIER(this, offset, value, UPDATE_WRITE_BARRIER);
return old_value;
}
Tagged<Object> JSObject::RawFastPropertyAtSwap(FieldIndex index,
Tagged<Object> value,
SeqCstAccessTag tag) {
if (index.is_inobject()) {
return RawFastInobjectPropertyAtSwap(index, value, tag);
}
return property_array()->Swap(index.outobject_array_index(), value, tag);
}
Tagged<Object> JSObject::RawFastInobjectPropertyAtCompareAndSwap(
FieldIndex index, Tagged<Object> expected, Tagged<Object> value,
SeqCstAccessTag tag) {
DCHECK(index.is_inobject());
DCHECK(IsShared(value));
Tagged<Object> previous_value =
SEQ_CST_COMPARE_AND_SWAP_FIELD(this, index.offset(), expected, value);
if (previous_value == expected) {
CONDITIONAL_WRITE_BARRIER(this, index.offset(), value,
UPDATE_WRITE_BARRIER);
}
return previous_value;
}
Tagged<Object> JSObject::RawFastPropertyAtCompareAndSwapInternal(
FieldIndex index, Tagged<Object> expected, Tagged<Object> value,
SeqCstAccessTag tag) {
if (index.is_inobject()) {
return RawFastInobjectPropertyAtCompareAndSwap(index, expected, value, tag);
}
return property_array()->CompareAndSwap(index.outobject_array_index(),
expected, value, tag);
}
int JSObject::GetInObjectPropertyOffset(int index) {
return map()->GetInObjectPropertyOffset(index);
}
Tagged<Object> JSObject::InObjectPropertyAtOffset(int offset) {
DCHECK_GE(offset, GetInObjectPropertyOffset(0));
DCHECK_LT(offset, Size());
return TaggedField<Object>::load(this, offset);
}
Tagged<Object> JSObject::InObjectPropertyPutAtIndex(int index,
Tagged<Object> value,
WriteBarrierMode mode) {
// Adjust for the number of properties stored in the object.
return InObjectPropertyPutAtOffset(GetInObjectPropertyOffset(index), value,
mode);
}
Tagged<Object> JSObject::InObjectPropertyPutAtOffset(int offset,
Tagged<Object> value,
WriteBarrierMode mode) {
DCHECK_GE(offset, GetInObjectPropertyOffset(0));
DCHECK_LT(offset, Size());
WRITE_FIELD(this, offset, value);
CONDITIONAL_WRITE_BARRIER(this, offset, value, mode);
return value;
}
void JSObject::InitializeBody(Tagged<Map> map, int start_offset,
bool is_slack_tracking_in_progress,
NewJSObjectType new_js_object_type) {
const uint32_t size = map->instance_size();
uint32_t current_offset = start_offset;
#if V8_STATIC_ROOTS_BOOL
using FillerType = Tagged_t;
constexpr Tagged_t undefined_filler = StaticReadOnlyRoot::kUndefinedValue;
constexpr Tagged_t filler_map = StaticReadOnlyRoot::kOnePointerFillerMap;
#else // !STATIC_ROOTS_BOOL
using FillerType = Tagged<HeapObject>;
Tagged<Undefined> undefined_filler = GetReadOnlyRoots().undefined_value();
Tagged<Map> filler_map = GetReadOnlyRoots().one_pointer_filler_map();
#endif // !STATIC_ROOTS_BOOL
// Fills memory at current offset and moves forward the offset.
const auto FillMemoryTaggedUntil =
[this, &current_offset, size](uint32_t end_offset, FillerType filler) {
DCHECK_LE(kHeaderSize, current_offset);
DCHECK_LE(current_offset, end_offset);
DCHECK_LE(end_offset, size);
USE(size);
// TODO(442989225): This loop should ideally be just a MemsetTagged().
// Unfortunately, this currently results in performance regressions.
while (current_offset < end_offset) {
#if V8_STATIC_ROOTS_BOOL
RELAXED_WRITE_UINT32_FIELD(this, current_offset, filler);
#else // !STATIC_ROOTS_BOOL
WRITE_FIELD(this, current_offset, filler);
#endif // !STATIC_ROOTS_BOOL
current_offset += kTaggedSize;
}
DCHECK_LE(current_offset, size);
};
DCHECK_IMPLIES(
new_js_object_type == NewJSObjectType::kNoEmbedderFieldsAndNoApiWrapper,
!MayHaveEmbedderFields(map));
DCHECK_IMPLIES(!MayHaveEmbedderFields(map), GetEmbedderFieldCount(map) == 0);
if (new_js_object_type != NewJSObjectType::kNoEmbedderFieldsAndNoApiWrapper &&
MayHaveEmbedderFields(map)) {
const uint32_t embedder_field_start = GetEmbedderFieldsStartOffset(map);
// Fill start with references to the undefined value object.
FillMemoryTaggedUntil(embedder_field_start, undefined_filler);
// Initialize embedder data slots.
DCHECK_EQ(current_offset, embedder_field_start);
for (int i = 0; i < GetEmbedderFieldCount(map); i++) {
// TODO(v8): consider initializing embedded data slots with Smi::zero().
EmbedderDataSlot(this, i).Initialize(
GetReadOnlyRoots().undefined_value());
current_offset += kEmbedderDataSlotSize;
}
}
DCHECK_LE(current_offset, size);
if (is_slack_tracking_in_progress) {
const uint32_t end_of_pre_allocated_offset =
size - (map->UnusedPropertyFields() * kTaggedSize);
// Fill pre allocated slots with references to the undefined value object.
FillMemoryTaggedUntil(end_of_pre_allocated_offset, undefined_filler);
// Fill the remainder with one word filler objects (ie just a map word)
FillMemoryTaggedUntil(size, filler_map);
} else {
FillMemoryTaggedUntil(size, undefined_filler);
}
}
template <typename T, template <typename> typename HandleType>
requires(std::is_convertible_v<HandleType<T>, DirectHandle<T>>)
inline typename HandleType<Object>::MaybeType
JSObject::DefineOwnPropertyIgnoreAttributes(LookupIterator* it,
HandleType<T> value,
PropertyAttributes attributes,
AccessorInfoHandling handling,
EnforceDefineSemantics semantics) {
MAYBE_RETURN_NULL(DefineOwnPropertyIgnoreAttributes(
it, value, attributes, Just(ShouldThrow::kThrowOnError), handling,
semantics));
return value;
}
void* JSExternalObject::value(ExternalPointerTagRange tag_range) const {
i::IsolateForSandbox isolate = GetCurrentIsolateForSandbox();
return value(isolate, tag_range);
}
void* JSExternalObject::value(i::IsolateForSandbox isolate,
ExternalPointerTagRange tag_range) const {
// Accessors take a runtime tag / tag_range (callers pick it dynamically
// based on v8::External tag values); ExternalPointerMember's template
// member variants require compile-time tags, so route through the
// field_address-based free functions instead.
Address result = ::v8::internal::ReadExternalPointerField(
value_.storage_address(), isolate, tag_range);
return reinterpret_cast<void*>(result);
}
void JSExternalObject::init_value(i::IsolateForSandbox isolate,
ExternalPointerTag tag, void* initial_value) {
::v8::internal::InitExternalPointerField(
reinterpret_cast<Address>(this), value_.storage_address(), isolate, tag,
reinterpret_cast<Address>(initial_value));
}
void JSExternalObject::set_value(i::IsolateForSandbox isolate,
ExternalPointerTag tag, void* value) {
::v8::internal::WriteExternalPointerField(
value_.storage_address(), isolate, tag, reinterpret_cast<Address>(value));
}
Tagged<String> JSStringIterator::string() const { return string_.load(); }
void JSStringIterator::set_string(Tagged<String> value, WriteBarrierMode mode) {
string_.store(this, value, mode);
}
int JSStringIterator::index() const { return index_.load().value(); }
void JSStringIterator::set_index(int value) {
index_.store(this, Smi::FromInt(value));
}
Tagged<JSReceiver> JSAsyncFromSyncIterator::sync_iterator() const {
return sync_iterator_.load();
}
void JSAsyncFromSyncIterator::set_sync_iterator(Tagged<JSReceiver> value,
WriteBarrierMode mode) {
sync_iterator_.store(this, value, mode);
}
Tagged<Object> JSAsyncFromSyncIterator::next() const { return next_.load(); }
void JSAsyncFromSyncIterator::set_next(Tagged<Object> value,
WriteBarrierMode mode) {
next_.store(this, value, mode);
}
Tagged<JSAny> JSPrimitiveWrapper::value() const { return value_.load(); }
void JSPrimitiveWrapper::set_value(Tagged<JSAny> value, WriteBarrierMode mode) {
value_.store(this, value, mode);
}
Tagged<JSReceiver> JSValidIteratorWrapper::underlying_object() const {
return underlying_object_.load();
}
void JSValidIteratorWrapper::set_underlying_object(Tagged<JSReceiver> value,
WriteBarrierMode mode) {
underlying_object_.store(this, value, mode);
}
Tagged<JSAny> JSValidIteratorWrapper::underlying_next() const {
return underlying_next_.load();
}
void JSValidIteratorWrapper::set_underlying_next(Tagged<JSAny> value,
WriteBarrierMode mode) {
underlying_next_.store(this, value, mode);
}
double JSDate::value() const { return value_.value(); }
void JSDate::set_value(double v) { value_.set_value(v); }
#define DEFINE_JSDATE_CACHED_ACCESSOR(name) \
Tagged<UnionOf<Smi, HeapNumber>> JSDate::name() const { \
return name##_.load(); \
} \
void JSDate::set_##name(Tagged<UnionOf<Smi, HeapNumber>> value, \
WriteBarrierMode mode) { \
name##_.store(this, value, mode); \
}
DEFINE_JSDATE_CACHED_ACCESSOR(year)
DEFINE_JSDATE_CACHED_ACCESSOR(month)
DEFINE_JSDATE_CACHED_ACCESSOR(day)
DEFINE_JSDATE_CACHED_ACCESSOR(weekday)
DEFINE_JSDATE_CACHED_ACCESSOR(hour)
DEFINE_JSDATE_CACHED_ACCESSOR(min)
DEFINE_JSDATE_CACHED_ACCESSOR(sec)
DEFINE_JSDATE_CACHED_ACCESSOR(cache_stamp)
#undef DEFINE_JSDATE_CACHED_ACCESSOR
bool JSMessageObject::DidEnsureSourcePositionsAvailable() const {
return shared_info() == Smi::zero();
}
// static
void JSMessageObject::EnsureSourcePositionsAvailable(
Isolate* isolate, DirectHandle<JSMessageObject> message) {
if (message->DidEnsureSourcePositionsAvailable()) {
DCHECK(message->script()->has_line_ends());
} else {
JSMessageObject::InitializeSourcePositions(isolate, message);
}
}
int JSMessageObject::GetStartPosition() const {
// TODO(cbruni): make this DCHECK stricter (>= 0).
DCHECK_LE(-1, start_position());
return start_position();
}
int JSMessageObject::GetEndPosition() const {
// TODO(cbruni): make this DCHECK stricter (>= 0).
DCHECK_LE(-1, end_position());
return end_position();
}
MessageTemplate JSMessageObject::type() const {
return MessageTemplateFromInt(raw_type());
}
void JSMessageObject::set_type(MessageTemplate value) {
set_raw_type(static_cast<int>(value));
}
Tagged<Object> JSMessageObject::shared_info() const {
return shared_info_.load();
}
void JSMessageObject::set_shared_info(Tagged<Object> value,
WriteBarrierMode mode) {
shared_info_.store(this, Cast<UnionOf<SharedFunctionInfo, Smi>>(value), mode);
}
Tagged<Smi> JSMessageObject::bytecode_offset() const {
return bytecode_offset_.load();
}
void JSMessageObject::set_bytecode_offset(Tagged<Smi> value) {
bytecode_offset_.store(this, value);
}
int JSMessageObject::start_position() const {
return start_position_.load().value();
}
void JSMessageObject::set_start_position(int value) {
start_position_.store(this, Smi::FromInt(value));
}
int JSMessageObject::end_position() const {
return end_position_.load().value();
}
void JSMessageObject::set_end_position(int value) {
end_position_.store(this, Smi::FromInt(value));
}
int JSMessageObject::error_level() const { return error_level_.load().value(); }
void JSMessageObject::set_error_level(int value) {
error_level_.store(this, Smi::FromInt(value));
}
int JSMessageObject::raw_type() const { return message_type_.load().value(); }
void JSMessageObject::set_raw_type(int value) {
message_type_.store(this, Smi::FromInt(value));
}
Tagged<Object> JSMessageObject::argument() const { return argument_.load(); }
void JSMessageObject::set_argument(Tagged<Object> value,
WriteBarrierMode mode) {
argument_.store(this, value, mode);
}
Tagged<Script> JSMessageObject::script() const { return script_.load(); }
void JSMessageObject::set_script(Tagged<Script> value, WriteBarrierMode mode) {
script_.store(this, value, mode);
}
Tagged<UnionOf<StackTraceInfo, Hole>> JSMessageObject::stack_trace() const {
return stack_trace_.load();
}
void JSMessageObject::set_stack_trace(
Tagged<UnionOf<StackTraceInfo, Hole>> value, WriteBarrierMode mode) {
stack_trace_.store(this, value, mode);
}
DEF_GETTER(JSObject, GetElementsKind, ElementsKind) {
ElementsKind kind = map()->elements_kind();
#if VERIFY_HEAP && DEBUG
Tagged<FixedArrayBase> fixed_array = UncheckedCast<FixedArrayBase>(
TaggedField<HeapObject, offsetof(JSObject, elements_)>::load(this));
// If a GC was caused while constructing this object, the elements
// pointer may point to a one pointer filler map.
if (ElementsAreSafeToExamine()) {
Tagged<Map> map = fixed_array->map();
if (IsSmiOrObjectElementsKind(kind)) {
CHECK(map == GetReadOnlyRoots().fixed_array_map() ||
map == GetReadOnlyRoots().fixed_cow_array_map());
} else if (IsDoubleElementsKind(kind)) {
CHECK(IsFixedDoubleArray(fixed_array) ||
fixed_array == GetReadOnlyRoots().empty_fixed_array());
} else if (kind == DICTIONARY_ELEMENTS) {
CHECK(IsFixedArray(fixed_array));
CHECK(IsNumberDictionary(fixed_array));
} else {
CHECK(kind > DICTIONARY_ELEMENTS || IsAnyNonextensibleElementsKind(kind));
}
CHECK_IMPLIES(IsSloppyArgumentsElementsKind(kind),
IsSloppyArgumentsElements(elements()));
}
#endif
return kind;
}
DEF_GETTER(JSObject, GetElementsAccessor, ElementsAccessor*) {
return ElementsAccessor::ForKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasObjectElements, bool) {
return IsObjectElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasSmiElements, bool) {
return IsSmiElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasSmiOrObjectElements, bool) {
return IsSmiOrObjectElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasDoubleElements, bool) {
return IsDoubleElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasHoleyElements, bool) {
return IsHoleyElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasFastElements, bool) {
return IsFastElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasFastPackedElements, bool) {
return IsFastPackedElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasDictionaryElements, bool) {
return IsDictionaryElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasPackedElements, bool) {
return GetElementsKind() == PACKED_ELEMENTS;
}
DEF_GETTER(JSObject, HasAnyNonextensibleElements, bool) {
return IsAnyNonextensibleElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasSealedElements, bool) {
return IsSealedElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasSharedArrayElements, bool) {
return GetElementsKind() == SHARED_ARRAY_ELEMENTS;
}
DEF_GETTER(JSObject, HasNonextensibleElements, bool) {
return IsNonextensibleElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasFastArgumentsElements, bool) {
return IsFastArgumentsElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasSlowArgumentsElements, bool) {
return IsSlowArgumentsElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasSloppyArgumentsElements, bool) {
return IsSloppyArgumentsElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasStringWrapperElements, bool) {
return IsStringWrapperElementsKind(GetElementsKind());
}
DEF_GETTER(JSObject, HasFastStringWrapperElements, bool) {
return GetElementsKind() == FAST_STRING_WRAPPER_ELEMENTS;
}
DEF_GETTER(JSObject, HasSlowStringWrapperElements, bool) {
return GetElementsKind() == SLOW_STRING_WRAPPER_ELEMENTS;
}
DEF_GETTER(JSObject, HasTypedArrayOrRabGsabTypedArrayElements, bool) {
DCHECK(!elements().is_null());
return map()->has_typed_array_or_rab_gsab_typed_array_elements();
}
#define FIXED_TYPED_ELEMENTS_CHECK(Type, type, TYPE, ctype) \
DEF_GETTER(JSObject, HasFixed##Type##Elements, bool) { \
return map()->elements_kind() == TYPE##_ELEMENTS; \
}
TYPED_ARRAYS(FIXED_TYPED_ELEMENTS_CHECK)
#undef FIXED_TYPED_ELEMENTS_CHECK
DEF_GETTER(JSObject, HasNamedInterceptor, bool) {
return map()->has_named_interceptor();
}
DEF_GETTER(JSObject, HasIndexedInterceptor, bool) {
return map()->has_indexed_interceptor();
}
Tagged<JSGlobalProxy> JSGlobalObject::global_proxy() const {
return global_proxy_.load();
}
void JSGlobalObject::set_global_proxy(Tagged<JSGlobalProxy> value,
WriteBarrierMode mode) {
global_proxy_.store(this, value, mode);
}
Tagged<JSGlobalProxy> JSGlobalObject::global_proxy_for_api() const {
return global_proxy_for_api_.load();
}
void JSGlobalObject::set_global_proxy_for_api(Tagged<JSGlobalProxy> value,
WriteBarrierMode mode) {
global_proxy_for_api_.store(this, value, mode);
}
Tagged<GlobalDictionary> JSGlobalObject::global_dictionary(
AcquireLoadTag) const {
DCHECK(!HasFastProperties());
return Cast<GlobalDictionary>(properties_or_hash_.Acquire_Load());
}
void JSGlobalObject::set_global_dictionary(Tagged<GlobalDictionary> value,
ReleaseStoreTag,
WriteBarrierMode mode) {
properties_or_hash_.Release_Store(this, Cast<FixedArrayBase>(value), mode);
}
Tagged<HeapObject> JSGlobalObject::raw_global_proxy() const {
return Cast<HeapObject>(global_proxy_.load());
}
DEF_GETTER(JSObject, element_dictionary, Tagged<NumberDictionary>) {
DCHECK(HasDictionaryElements() || HasSlowStringWrapperElements());
return Cast<NumberDictionary>(elements());
}
void JSReceiver::initialize_properties(Isolate* isolate) {
ReadOnlyRoots roots(isolate);
DCHECK(!HeapLayout::InYoungGeneration(roots.empty_fixed_array()));
DCHECK(!HeapLayout::InYoungGeneration(roots.empty_property_dictionary()));
DCHECK(!HeapLayout::InYoungGeneration(
roots.empty_ordered_property_dictionary()));
if (map()->is_dictionary_map()) {
if (V8_ENABLE_SWISS_NAME_DICTIONARY_BOOL) {
properties_or_hash_.store_no_write_barrier(
roots.empty_swiss_property_dictionary());
} else {
properties_or_hash_.store_no_write_barrier(
roots.empty_property_dictionary());
}
} else {
properties_or_hash_.store_no_write_barrier(roots.empty_fixed_array());
}
}
DEF_GETTER(JSReceiver, HasFastProperties, bool) {
Tagged<JSReceiver::PropertiesOrHash> properties_or_hash_obj =
raw_properties_or_hash(kRelaxedLoad);
DCHECK(IsSmi(properties_or_hash_obj) ||
((IsGlobalDictionary(properties_or_hash_obj) ||
IsPropertyDictionary(properties_or_hash_obj)) ==
map()->is_dictionary_map()));
USE(properties_or_hash_obj);
return !map()->is_dictionary_map();
}
DEF_GETTER(JSReceiver, property_dictionary, Tagged<NameDictionary>) {
DCHECK(!Is<JSGlobalObject>(this));
DCHECK(!HasFastProperties());
DCHECK(!V8_ENABLE_SWISS_NAME_DICTIONARY_BOOL);
Tagged<JSReceiver::PropertiesOrHash> prop = raw_properties_or_hash();
if (IsSmi(prop)) {
return GetReadOnlyRoots().empty_property_dictionary();
}
return Cast<NameDictionary>(prop);
}
DEF_GETTER(JSReceiver, property_dictionary_swiss, Tagged<SwissNameDictionary>) {
DCHECK(!Is<JSGlobalObject>(this));
DCHECK(!HasFastProperties());
DCHECK(V8_ENABLE_SWISS_NAME_DICTIONARY_BOOL);
Tagged<JSReceiver::PropertiesOrHash> prop = raw_properties_or_hash();
if (IsSmi(prop)) {
return GetReadOnlyRoots().empty_swiss_property_dictionary();
}
return Cast<SwissNameDictionary>(prop);
}
// TODO(gsathya): Pass isolate directly to this function and access
// the heap from this.
DEF_GETTER(JSReceiver, property_array, Tagged<PropertyArray>) {
DCHECK(HasFastProperties());
Tagged<JSReceiver::PropertiesOrHash> prop = raw_properties_or_hash();
if (IsSmi(prop) || prop == GetReadOnlyRoots().empty_fixed_array()) {
return GetReadOnlyRoots().empty_property_array();
}
return Cast<PropertyArray>(prop);
}
void JSObject::EnsureWritableFastElements(Isolate* isolate,
DirectHandle<JSObject> object) {
DCHECK(object->HasSmiOrObjectElements() ||
object->HasFastStringWrapperElements() ||
object->HasAnyNonextensibleElements());
Tagged<FixedArray> raw_elems = Cast<FixedArray>(object->elements());
if (V8_UNLIKELY(raw_elems->map() ==
ReadOnlyRoots(isolate).fixed_cow_array_map())) {
MakeElementsWritable(isolate, object);
}
}
std::optional<Tagged<NativeContext>> JSReceiver::GetCreationContext() const {
DisallowGarbageCollection no_gc;
Tagged<Map> meta_map = map()->map();
DCHECK(IsMapMap(meta_map));
Tagged<Object> maybe_native_context = meta_map->native_context_or_null();
if (V8_UNLIKELY(IsNull(maybe_native_context))) return {};
DCHECK(IsNativeContext(maybe_native_context));
return Cast<NativeContext>(maybe_native_context);
}
MaybeDirectHandle<NativeContext> JSReceiver::GetCreationContext(
Isolate* isolate) const {
DisallowGarbageCollection no_gc;
std::optional<Tagged<NativeContext>> maybe_context = GetCreationContext();
if (!maybe_context.has_value()) return {};
return direct_handle(maybe_context.value(), isolate);
}
Maybe<bool> JSReceiver::HasProperty(Isolate* isolate,
DirectHandle<JSReceiver> object,
DirectHandle<Name> name) {
return HasPropertyOrElement(isolate, object, PropertyKey(isolate, name));
}
Maybe<bool> JSReceiver::HasElement(Isolate* isolate,
DirectHandle<JSReceiver> object,
uint32_t index) {
LookupIterator it(isolate, object, index, object);
return HasProperty(&it);
}
Maybe<bool> JSReceiver::HasPropertyOrElement(Isolate* isolate,
DirectHandle<JSReceiver> object,
PropertyKey key) {
LookupIterator it(isolate, object, key, object);
return HasProperty(&it);
}
Maybe<bool> JSReceiver::HasOwnProperty(Isolate* isolate,
DirectHandle<JSReceiver> object,
size_t index) {
if (IsJSObject(*object)) { // Shortcut.
LookupIterator it(isolate, object, index, object, LookupIterator::OWN);
return HasProperty(&it);
}
Maybe<PropertyAttributes> attributes =
JSReceiver::GetOwnPropertyAttributes(isolate, object, index);
MAYBE_RETURN(attributes, Nothing<bool>());
return Just(attributes.FromJust() != ABSENT);
}
Maybe<PropertyAttributes> JSReceiver::GetPropertyAttributes(
Isolate* isolate, DirectHandle<JSReceiver> object,
DirectHandle<Name> name) {
PropertyKey key(isolate, name);
LookupIterator it(isolate, object, key, object);
return GetPropertyAttributes(&it);
}
Maybe<PropertyAttributes> JSReceiver::GetOwnPropertyAttributes(
Isolate* isolate, DirectHandle<JSReceiver> object,
DirectHandle<Name> name) {
PropertyKey key(isolate, name);
LookupIterator it(isolate, object, key, object, LookupIterator::OWN);
return GetPropertyAttributes(&it);
}
Maybe<PropertyAttributes> JSReceiver::GetOwnPropertyAttributes(
Isolate* isolate, DirectHandle<JSReceiver> object, size_t index) {
LookupIterator it(isolate, object, index, object, LookupIterator::OWN);
return GetPropertyAttributes(&it);
}
Maybe<PropertyAttributes> JSReceiver::GetElementAttributes(
Isolate* isolate, DirectHandle<JSReceiver> object, uint32_t index) {
LookupIterator it(isolate, object, index, object);
return GetPropertyAttributes(&it);
}
Maybe<PropertyAttributes> JSReceiver::GetOwnElementAttributes(
Isolate* isolate, DirectHandle<JSReceiver> object, uint32_t index) {
LookupIterator it(isolate, object, index, object, LookupIterator::OWN);
return GetPropertyAttributes(&it);
}
Tagged<NativeContext> JSGlobalObject::native_context() {
return *GetCreationContext();
}
bool JSGlobalObject::IsDetached() {
return global_proxy()->IsDetachedFrom(this);
}
bool JSGlobalProxy::IsDetachedFrom(Tagged<JSGlobalObject> global) const {
return map()->prototype() != global;
}
bool JSGlobalProxy::IsDetached() const {
// Currently we expect a non-detached global proxy to have a non-null
// hidden prototype.
bool is_detached = IsNull(map()->prototype());
DCHECK_IMPLIES(is_detached, !GetCreationContext().has_value());
return is_detached;
}
inline int JSGlobalProxy::SizeWithEmbedderFields(int embedder_field_count) {
DCHECK_GE(embedder_field_count, 0);
return kHeaderSize + embedder_field_count * kEmbedderDataSlotSize;
}
ACCESSORS(JSIteratorResult, value, Tagged<Object>, kValueOffset)
ACCESSORS(JSIteratorResult, done, Tagged<Object>, kDoneOffset)
ACCESSORS(JSUint8ArraySetFromResult, read, Tagged<Object>, kReadOffset)
ACCESSORS(JSUint8ArraySetFromResult, written, Tagged<Object>, kWrittenOffset)
// If the fast-case backing storage takes up much more memory than a dictionary
// backing storage would, the object should have slow elements.
// static
static inline bool ShouldConvertToSlowElements(uint32_t used_elements,
uint32_t new_capacity) {
uint32_t size_threshold = NumberDictionary::kPreferFastElementsSizeFactor *
NumberDictionary::ComputeCapacity(used_elements) *
NumberDictionary::kEntrySize;
return size_threshold <= new_capacity;
}
static inline bool ShouldConvertToSlowElements(Tagged<JSObject> object,
uint32_t capacity,
uint32_t index,
uint32_t* new_capacity) {
static_assert(JSObject::kMaxUncheckedOldFastElementsLength <=
JSObject::kMaxUncheckedFastElementsLength);
if (index < capacity) {
*new_capacity = capacity;
return false;
}
if (index - capacity >= JSObject::kMaxGap) return true;
*new_capacity = JSObject::NewElementsCapacity(index + 1);
DCHECK_LT(index, *new_capacity);
if (*new_capacity <= JSObject::kMaxUncheckedOldFastElementsLength ||
(*new_capacity <= JSObject::kMaxUncheckedFastElementsLength &&
HeapLayout::InYoungGeneration(object))) {
return false;
}
return ShouldConvertToSlowElements(object->GetFastElementsUsage(),
*new_capacity);
}
} // namespace v8::internal
#include "src/objects/object-macros-undef.h"
#endif // V8_OBJECTS_JS_OBJECTS_INL_H_