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cobalt / cobalt / ef837fa448402e2ada2fb3821210cc20d850164b / . / src / v8 / src / builtins / builtins-array.cc
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// Copyright 2016 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/builtins/builtins.h"
#include "src/builtins/builtins-utils.h"
#include "src/code-factory.h"
#include "src/code-stub-assembler.h"
#include "src/contexts.h"
#include "src/counters.h"
#include "src/elements.h"
#include "src/isolate.h"
#include "src/lookup.h"
#include "src/objects-inl.h"
#include "src/prototype.h"
namespace v8 {
namespace internal {
namespace {
inline bool ClampedToInteger(Isolate* isolate, Object* object, int* out) {
// This is an extended version of ECMA-262 7.1.11 handling signed values
// Try to convert object to a number and clamp values to [kMinInt, kMaxInt]
if (object->IsSmi()) {
*out = Smi::ToInt(object);
return true;
} else if (object->IsHeapNumber()) {
double value = HeapNumber::cast(object)->value();
if (std::isnan(value)) {
*out = 0;
} else if (value > kMaxInt) {
*out = kMaxInt;
} else if (value < kMinInt) {
*out = kMinInt;
} else {
*out = static_cast<int>(value);
}
return true;
} else if (object->IsNullOrUndefined(isolate)) {
*out = 0;
return true;
} else if (object->IsBoolean()) {
*out = object->IsTrue(isolate);
return true;
}
return false;
}
inline bool GetSloppyArgumentsLength(Isolate* isolate, Handle<JSObject> object,
int* out) {
Context* context = *isolate->native_context();
Map* map = object->map();
if (map != context->sloppy_arguments_map() &&
map != context->strict_arguments_map() &&
map != context->fast_aliased_arguments_map()) {
return false;
}
DCHECK(object->HasFastElements() || object->HasFastArgumentsElements());
Object* len_obj = object->InObjectPropertyAt(JSArgumentsObject::kLengthIndex);
if (!len_obj->IsSmi()) return false;
*out = Max(0, Smi::ToInt(len_obj));
FixedArray* parameters = FixedArray::cast(object->elements());
if (object->HasSloppyArgumentsElements()) {
FixedArray* arguments = FixedArray::cast(parameters->get(1));
return *out <= arguments->length();
}
return *out <= parameters->length();
}
inline bool IsJSArrayFastElementMovingAllowed(Isolate* isolate,
JSArray* receiver) {
return JSObject::PrototypeHasNoElements(isolate, receiver);
}
inline bool HasSimpleElements(JSObject* current) {
return current->map()->instance_type() > LAST_CUSTOM_ELEMENTS_RECEIVER &&
!current->GetElementsAccessor()->HasAccessors(current);
}
inline bool HasOnlySimpleReceiverElements(Isolate* isolate,
JSObject* receiver) {
// Check that we have no accessors on the receiver's elements.
if (!HasSimpleElements(receiver)) return false;
return JSObject::PrototypeHasNoElements(isolate, receiver);
}
inline bool HasOnlySimpleElements(Isolate* isolate, JSReceiver* receiver) {
DisallowHeapAllocation no_gc;
PrototypeIterator iter(isolate, receiver, kStartAtReceiver);
for (; !iter.IsAtEnd(); iter.Advance()) {
if (iter.GetCurrent()->IsJSProxy()) return false;
JSObject* current = iter.GetCurrent<JSObject>();
if (!HasSimpleElements(current)) return false;
}
return true;
}
// Returns |false| if not applicable.
MUST_USE_RESULT
inline bool EnsureJSArrayWithWritableFastElements(Isolate* isolate,
Handle<Object> receiver,
BuiltinArguments* args,
int first_added_arg) {
if (!receiver->IsJSArray()) return false;
Handle<JSArray> array = Handle<JSArray>::cast(receiver);
ElementsKind origin_kind = array->GetElementsKind();
if (IsDictionaryElementsKind(origin_kind)) return false;
if (!array->map()->is_extensible()) return false;
if (args == nullptr) return true;
// If there may be elements accessors in the prototype chain, the fast path
// cannot be used if there arguments to add to the array.
if (!IsJSArrayFastElementMovingAllowed(isolate, *array)) return false;
// Adding elements to the array prototype would break code that makes sure
// it has no elements. Handle that elsewhere.
if (isolate->IsAnyInitialArrayPrototype(array)) return false;
// Need to ensure that the arguments passed in args can be contained in
// the array.
int args_length = args->length();
if (first_added_arg >= args_length) return true;
if (IsObjectElementsKind(origin_kind)) return true;
ElementsKind target_kind = origin_kind;
{
DisallowHeapAllocation no_gc;
for (int i = first_added_arg; i < args_length; i++) {
Object* arg = (*args)[i];
if (arg->IsHeapObject()) {
if (arg->IsHeapNumber()) {
target_kind = PACKED_DOUBLE_ELEMENTS;
} else {
target_kind = PACKED_ELEMENTS;
break;
}
}
}
}
if (target_kind != origin_kind) {
// Use a short-lived HandleScope to avoid creating several copies of the
// elements handle which would cause issues when left-trimming later-on.
HandleScope scope(isolate);
JSObject::TransitionElementsKind(array, target_kind);
}
return true;
}
MUST_USE_RESULT static Object* CallJsIntrinsic(Isolate* isolate,
Handle<JSFunction> function,
BuiltinArguments args) {
HandleScope handleScope(isolate);
int argc = args.length() - 1;
ScopedVector<Handle<Object>> argv(argc);
for (int i = 0; i < argc; ++i) {
argv[i] = args.at(i + 1);
}
RETURN_RESULT_OR_FAILURE(
isolate,
Execution::Call(isolate, function, args.receiver(), argc, argv.start()));
}
} // namespace
BUILTIN(ArrayPush) {
HandleScope scope(isolate);
Handle<Object> receiver = args.receiver();
if (!EnsureJSArrayWithWritableFastElements(isolate, receiver, &args, 1)) {
return CallJsIntrinsic(isolate, isolate->array_push(), args);
}
// Fast Elements Path
int to_add = args.length() - 1;
Handle<JSArray> array = Handle<JSArray>::cast(receiver);
int len = Smi::ToInt(array->length());
if (to_add == 0) return Smi::FromInt(len);
// Currently fixed arrays cannot grow too big, so we should never hit this.
DCHECK_LE(to_add, Smi::kMaxValue - Smi::ToInt(array->length()));
if (JSArray::HasReadOnlyLength(array)) {
return CallJsIntrinsic(isolate, isolate->array_push(), args);
}
ElementsAccessor* accessor = array->GetElementsAccessor();
int new_length = accessor->Push(array, &args, to_add);
return Smi::FromInt(new_length);
}
BUILTIN(ArrayPop) {
HandleScope scope(isolate);
Handle<Object> receiver = args.receiver();
if (!EnsureJSArrayWithWritableFastElements(isolate, receiver, nullptr, 0)) {
return CallJsIntrinsic(isolate, isolate->array_pop(), args);
}
Handle<JSArray> array = Handle<JSArray>::cast(receiver);
uint32_t len = static_cast<uint32_t>(Smi::ToInt(array->length()));
if (len == 0) return isolate->heap()->undefined_value();
if (JSArray::HasReadOnlyLength(array)) {
return CallJsIntrinsic(isolate, isolate->array_pop(), args);
}
Handle<Object> result;
if (IsJSArrayFastElementMovingAllowed(isolate, JSArray::cast(*receiver))) {
// Fast Elements Path
result = array->GetElementsAccessor()->Pop(array);
} else {
// Use Slow Lookup otherwise
uint32_t new_length = len - 1;
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
isolate, result, JSReceiver::GetElement(isolate, array, new_length));
JSArray::SetLength(array, new_length);
}
return *result;
}
BUILTIN(ArrayShift) {
HandleScope scope(isolate);
Heap* heap = isolate->heap();
Handle<Object> receiver = args.receiver();
if (!EnsureJSArrayWithWritableFastElements(isolate, receiver, nullptr, 0) ||
!IsJSArrayFastElementMovingAllowed(isolate, JSArray::cast(*receiver))) {
return CallJsIntrinsic(isolate, isolate->array_shift(), args);
}
Handle<JSArray> array = Handle<JSArray>::cast(receiver);
int len = Smi::ToInt(array->length());
if (len == 0) return heap->undefined_value();
if (JSArray::HasReadOnlyLength(array)) {
return CallJsIntrinsic(isolate, isolate->array_shift(), args);
}
Handle<Object> first = array->GetElementsAccessor()->Shift(array);
return *first;
}
BUILTIN(ArrayUnshift) {
HandleScope scope(isolate);
Handle<Object> receiver = args.receiver();
if (!EnsureJSArrayWithWritableFastElements(isolate, receiver, &args, 1)) {
return CallJsIntrinsic(isolate, isolate->array_unshift(), args);
}
Handle<JSArray> array = Handle<JSArray>::cast(receiver);
int to_add = args.length() - 1;
if (to_add == 0) return array->length();
// Currently fixed arrays cannot grow too big, so we should never hit this.
DCHECK_LE(to_add, Smi::kMaxValue - Smi::ToInt(array->length()));
if (JSArray::HasReadOnlyLength(array)) {
return CallJsIntrinsic(isolate, isolate->array_unshift(), args);
}
ElementsAccessor* accessor = array->GetElementsAccessor();
int new_length = accessor->Unshift(array, &args, to_add);
return Smi::FromInt(new_length);
}
BUILTIN(ArraySlice) {
HandleScope scope(isolate);
Handle<Object> receiver = args.receiver();
int len = -1;
int relative_start = 0;
int relative_end = 0;
if (receiver->IsJSArray()) {
DisallowHeapAllocation no_gc;
JSArray* array = JSArray::cast(*receiver);
if (V8_UNLIKELY(!array->HasFastElements() ||
!IsJSArrayFastElementMovingAllowed(isolate, array) ||
!isolate->IsArraySpeciesLookupChainIntact() ||
// If this is a subclass of Array, then call out to JS
!array->HasArrayPrototype(isolate))) {
AllowHeapAllocation allow_allocation;
return CallJsIntrinsic(isolate, isolate->array_slice(), args);
}
len = Smi::ToInt(array->length());
} else if (receiver->IsJSObject() &&
GetSloppyArgumentsLength(isolate, Handle<JSObject>::cast(receiver),
&len)) {
// Array.prototype.slice.call(arguments, ...) is quite a common idiom
// (notably more than 50% of invocations in Web apps).
// Treat it in C++ as well.
DCHECK(JSObject::cast(*receiver)->HasFastElements() ||
JSObject::cast(*receiver)->HasFastArgumentsElements());
} else {
AllowHeapAllocation allow_allocation;
return CallJsIntrinsic(isolate, isolate->array_slice(), args);
}
DCHECK_LE(0, len);
int argument_count = args.length() - 1;
// Note carefully chosen defaults---if argument is missing,
// it's undefined which gets converted to 0 for relative_start
// and to len for relative_end.
relative_start = 0;
relative_end = len;
if (argument_count > 0) {
DisallowHeapAllocation no_gc;
if (!ClampedToInteger(isolate, args[1], &relative_start)) {
AllowHeapAllocation allow_allocation;
return CallJsIntrinsic(isolate, isolate->array_slice(), args);
}
if (argument_count > 1) {
Object* end_arg = args[2];
// slice handles the end_arg specially
if (end_arg->IsUndefined(isolate)) {
relative_end = len;
} else if (!ClampedToInteger(isolate, end_arg, &relative_end)) {
AllowHeapAllocation allow_allocation;
return CallJsIntrinsic(isolate, isolate->array_slice(), args);
}
}
}
// ECMAScript 232, 3rd Edition, Section 15.4.4.10, step 6.
uint32_t actual_start = (relative_start < 0) ? Max(len + relative_start, 0)
: Min(relative_start, len);
// ECMAScript 232, 3rd Edition, Section 15.4.4.10, step 8.
uint32_t actual_end =
(relative_end < 0) ? Max(len + relative_end, 0) : Min(relative_end, len);
Handle<JSObject> object = Handle<JSObject>::cast(receiver);
ElementsAccessor* accessor = object->GetElementsAccessor();
return *accessor->Slice(object, actual_start, actual_end);
}
BUILTIN(ArraySplice) {
HandleScope scope(isolate);
Handle<Object> receiver = args.receiver();
if (V8_UNLIKELY(
!EnsureJSArrayWithWritableFastElements(isolate, receiver, &args, 3) ||
// If this is a subclass of Array, then call out to JS.
!Handle<JSArray>::cast(receiver)->HasArrayPrototype(isolate) ||
// If anything with @@species has been messed with, call out to JS.
!isolate->IsArraySpeciesLookupChainIntact())) {
return CallJsIntrinsic(isolate, isolate->array_splice(), args);
}
Handle<JSArray> array = Handle<JSArray>::cast(receiver);
int argument_count = args.length() - 1;
int relative_start = 0;
if (argument_count > 0) {
DisallowHeapAllocation no_gc;
if (!ClampedToInteger(isolate, args[1], &relative_start)) {
AllowHeapAllocation allow_allocation;
return CallJsIntrinsic(isolate, isolate->array_splice(), args);
}
}
int len = Smi::ToInt(array->length());
// clip relative start to [0, len]
int actual_start = (relative_start < 0) ? Max(len + relative_start, 0)
: Min(relative_start, len);
int actual_delete_count;
if (argument_count == 1) {
// SpiderMonkey, TraceMonkey and JSC treat the case where no delete count is
// given as a request to delete all the elements from the start.
// And it differs from the case of undefined delete count.
// This does not follow ECMA-262, but we do the same for compatibility.
DCHECK(len - actual_start >= 0);
actual_delete_count = len - actual_start;
} else {
int delete_count = 0;
DisallowHeapAllocation no_gc;
if (argument_count > 1) {
if (!ClampedToInteger(isolate, args[2], &delete_count)) {
AllowHeapAllocation allow_allocation;
return CallJsIntrinsic(isolate, isolate->array_splice(), args);
}
}
actual_delete_count = Min(Max(delete_count, 0), len - actual_start);
}
int add_count = (argument_count > 1) ? (argument_count - 2) : 0;
int new_length = len - actual_delete_count + add_count;
if (new_length != len && JSArray::HasReadOnlyLength(array)) {
AllowHeapAllocation allow_allocation;
return CallJsIntrinsic(isolate, isolate->array_splice(), args);
}
ElementsAccessor* accessor = array->GetElementsAccessor();
Handle<JSArray> result_array = accessor->Splice(
array, actual_start, actual_delete_count, &args, add_count);
return *result_array;
}
// Array Concat -------------------------------------------------------------
namespace {
/**
* A simple visitor visits every element of Array's.
* The backend storage can be a fixed array for fast elements case,
* or a dictionary for sparse array. Since Dictionary is a subtype
* of FixedArray, the class can be used by both fast and slow cases.
* The second parameter of the constructor, fast_elements, specifies
* whether the storage is a FixedArray or Dictionary.
*
* An index limit is used to deal with the situation that a result array
* length overflows 32-bit non-negative integer.
*/
class ArrayConcatVisitor {
public:
ArrayConcatVisitor(Isolate* isolate, Handle<HeapObject> storage,
bool fast_elements)
: isolate_(isolate),
storage_(isolate->global_handles()->Create(*storage)),
index_offset_(0u),
bit_field_(
FastElementsField::encode(fast_elements) |
ExceedsLimitField::encode(false) |
IsFixedArrayField::encode(storage->IsFixedArray()) |
HasSimpleElementsField::encode(storage->IsFixedArray() ||
storage->map()->instance_type() >
LAST_CUSTOM_ELEMENTS_RECEIVER)) {
DCHECK(!(this->fast_elements() && !is_fixed_array()));
}
~ArrayConcatVisitor() { clear_storage(); }
MUST_USE_RESULT bool visit(uint32_t i, Handle<Object> elm) {
uint32_t index = index_offset_ + i;
if (i >= JSObject::kMaxElementCount - index_offset_) {
set_exceeds_array_limit(true);
// Exception hasn't been thrown at this point. Return true to
// break out, and caller will throw. !visit would imply that
// there is already a pending exception.
return true;
}
if (!is_fixed_array()) {
LookupIterator it(isolate_, storage_, index, LookupIterator::OWN);
MAYBE_RETURN(
JSReceiver::CreateDataProperty(&it, elm, Object::THROW_ON_ERROR),
false);
return true;
}
if (fast_elements()) {
if (index < static_cast<uint32_t>(storage_fixed_array()->length())) {
storage_fixed_array()->set(index, *elm);
return true;
}
// Our initial estimate of length was foiled, possibly by
// getters on the arrays increasing the length of later arrays
// during iteration.
// This shouldn't happen in anything but pathological cases.
SetDictionaryMode();
// Fall-through to dictionary mode.
}
DCHECK(!fast_elements());
Handle<SeededNumberDictionary> dict(
SeededNumberDictionary::cast(*storage_));
// The object holding this backing store has just been allocated, so
// it cannot yet be used as a prototype.
Handle<JSObject> not_a_prototype_holder;
Handle<SeededNumberDictionary> result =
SeededNumberDictionary::Set(dict, index, elm, not_a_prototype_holder);
if (!result.is_identical_to(dict)) {
// Dictionary needed to grow.
clear_storage();
set_storage(*result);
}
return true;
}
void increase_index_offset(uint32_t delta) {
if (JSObject::kMaxElementCount - index_offset_ < delta) {
index_offset_ = JSObject::kMaxElementCount;
} else {
index_offset_ += delta;
}
// If the initial length estimate was off (see special case in visit()),
// but the array blowing the limit didn't contain elements beyond the
// provided-for index range, go to dictionary mode now.
if (fast_elements() &&
index_offset_ >
static_cast<uint32_t>(FixedArrayBase::cast(*storage_)->length())) {
SetDictionaryMode();
}
}
bool exceeds_array_limit() const {
return ExceedsLimitField::decode(bit_field_);
}
Handle<JSArray> ToArray() {
DCHECK(is_fixed_array());
Handle<JSArray> array = isolate_->factory()->NewJSArray(0);
Handle<Object> length =
isolate_->factory()->NewNumber(static_cast<double>(index_offset_));
Handle<Map> map = JSObject::GetElementsTransitionMap(
array, fast_elements() ? HOLEY_ELEMENTS : DICTIONARY_ELEMENTS);
array->set_length(*length);
array->set_elements(*storage_fixed_array());
array->synchronized_set_map(*map);
return array;
}
MUST_USE_RESULT MaybeHandle<JSReceiver> ToJSReceiver() {
DCHECK(!is_fixed_array());
Handle<JSReceiver> result = Handle<JSReceiver>::cast(storage_);
Handle<Object> length =
isolate_->factory()->NewNumber(static_cast<double>(index_offset_));
RETURN_ON_EXCEPTION(
isolate_,
JSReceiver::SetProperty(result, isolate_->factory()->length_string(),
length, STRICT),
JSReceiver);
return result;
}
bool has_simple_elements() const {
return HasSimpleElementsField::decode(bit_field_);
}
private:
// Convert storage to dictionary mode.
void SetDictionaryMode() {
DCHECK(fast_elements() && is_fixed_array());
Handle<FixedArray> current_storage = storage_fixed_array();
Handle<SeededNumberDictionary> slow_storage(
SeededNumberDictionary::New(isolate_, current_storage->length()));
uint32_t current_length = static_cast<uint32_t>(current_storage->length());
FOR_WITH_HANDLE_SCOPE(
isolate_, uint32_t, i = 0, i, i < current_length, i++, {
Handle<Object> element(current_storage->get(i), isolate_);
if (!element->IsTheHole(isolate_)) {
// The object holding this backing store has just been allocated, so
// it cannot yet be used as a prototype.
Handle<JSObject> not_a_prototype_holder;
Handle<SeededNumberDictionary> new_storage =
SeededNumberDictionary::Set(slow_storage, i, element,
not_a_prototype_holder);
if (!new_storage.is_identical_to(slow_storage)) {
slow_storage = loop_scope.CloseAndEscape(new_storage);
}
}
});
clear_storage();
set_storage(*slow_storage);
set_fast_elements(false);
}
inline void clear_storage() { GlobalHandles::Destroy(storage_.location()); }
inline void set_storage(FixedArray* storage) {
DCHECK(is_fixed_array());
DCHECK(has_simple_elements());
storage_ = isolate_->global_handles()->Create(storage);
}
class FastElementsField : public BitField<bool, 0, 1> {};
class ExceedsLimitField : public BitField<bool, 1, 1> {};
class IsFixedArrayField : public BitField<bool, 2, 1> {};
class HasSimpleElementsField : public BitField<bool, 3, 1> {};
bool fast_elements() const { return FastElementsField::decode(bit_field_); }
void set_fast_elements(bool fast) {
bit_field_ = FastElementsField::update(bit_field_, fast);
}
void set_exceeds_array_limit(bool exceeds) {
bit_field_ = ExceedsLimitField::update(bit_field_, exceeds);
}
bool is_fixed_array() const { return IsFixedArrayField::decode(bit_field_); }
Handle<FixedArray> storage_fixed_array() {
DCHECK(is_fixed_array());
DCHECK(has_simple_elements());
return Handle<FixedArray>::cast(storage_);
}
Isolate* isolate_;
Handle<Object> storage_; // Always a global handle.
// Index after last seen index. Always less than or equal to
// JSObject::kMaxElementCount.
uint32_t index_offset_;
uint32_t bit_field_;
};
uint32_t EstimateElementCount(Handle<JSArray> array) {
DisallowHeapAllocation no_gc;
uint32_t length = static_cast<uint32_t>(array->length()->Number());
int element_count = 0;
switch (array->GetElementsKind()) {
case PACKED_SMI_ELEMENTS:
case HOLEY_SMI_ELEMENTS:
case PACKED_ELEMENTS:
case HOLEY_ELEMENTS: {
// Fast elements can't have lengths that are not representable by
// a 32-bit signed integer.
DCHECK(static_cast<int32_t>(FixedArray::kMaxLength) >= 0);
int fast_length = static_cast<int>(length);
Isolate* isolate = array->GetIsolate();
FixedArray* elements = FixedArray::cast(array->elements());
for (int i = 0; i < fast_length; i++) {
if (!elements->get(i)->IsTheHole(isolate)) element_count++;
}
break;
}
case PACKED_DOUBLE_ELEMENTS:
case HOLEY_DOUBLE_ELEMENTS: {
// Fast elements can't have lengths that are not representable by
// a 32-bit signed integer.
DCHECK(static_cast<int32_t>(FixedDoubleArray::kMaxLength) >= 0);
int fast_length = static_cast<int>(length);
if (array->elements()->IsFixedArray()) {
DCHECK(FixedArray::cast(array->elements())->length() == 0);
break;
}
FixedDoubleArray* elements = FixedDoubleArray::cast(array->elements());
for (int i = 0; i < fast_length; i++) {
if (!elements->is_the_hole(i)) element_count++;
}
break;
}
case DICTIONARY_ELEMENTS: {
SeededNumberDictionary* dictionary =
SeededNumberDictionary::cast(array->elements());
Isolate* isolate = dictionary->GetIsolate();
int capacity = dictionary->Capacity();
for (int i = 0; i < capacity; i++) {
Object* key = dictionary->KeyAt(i);
if (dictionary->IsKey(isolate, key)) {
element_count++;
}
}
break;
}
#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) case TYPE##_ELEMENTS:
TYPED_ARRAYS(TYPED_ARRAY_CASE)
#undef TYPED_ARRAY_CASE
// External arrays are always dense.
return length;
case NO_ELEMENTS:
return 0;
case FAST_SLOPPY_ARGUMENTS_ELEMENTS:
case SLOW_SLOPPY_ARGUMENTS_ELEMENTS:
case FAST_STRING_WRAPPER_ELEMENTS:
case SLOW_STRING_WRAPPER_ELEMENTS:
UNREACHABLE();
}
// As an estimate, we assume that the prototype doesn't contain any
// inherited elements.
return element_count;
}
void CollectElementIndices(Handle<JSObject> object, uint32_t range,
std::vector<uint32_t>* indices) {
Isolate* isolate = object->GetIsolate();
ElementsKind kind = object->GetElementsKind();
switch (kind) {
case PACKED_SMI_ELEMENTS:
case PACKED_ELEMENTS:
case HOLEY_SMI_ELEMENTS:
case HOLEY_ELEMENTS: {
DisallowHeapAllocation no_gc;
FixedArray* elements = FixedArray::cast(object->elements());
uint32_t length = static_cast<uint32_t>(elements->length());
if (range < length) length = range;
for (uint32_t i = 0; i < length; i++) {
if (!elements->get(i)->IsTheHole(isolate)) {
indices->push_back(i);
}
}
break;
}
case HOLEY_DOUBLE_ELEMENTS:
case PACKED_DOUBLE_ELEMENTS: {
if (object->elements()->IsFixedArray()) {
DCHECK(object->elements()->length() == 0);
break;
}
Handle<FixedDoubleArray> elements(
FixedDoubleArray::cast(object->elements()));
uint32_t length = static_cast<uint32_t>(elements->length());
if (range < length) length = range;
for (uint32_t i = 0; i < length; i++) {
if (!elements->is_the_hole(i)) {
indices->push_back(i);
}
}
break;
}
case DICTIONARY_ELEMENTS: {
DisallowHeapAllocation no_gc;
SeededNumberDictionary* dict =
SeededNumberDictionary::cast(object->elements());
uint32_t capacity = dict->Capacity();
FOR_WITH_HANDLE_SCOPE(isolate, uint32_t, j = 0, j, j < capacity, j++, {
Object* k = dict->KeyAt(j);
if (!dict->IsKey(isolate, k)) continue;
DCHECK(k->IsNumber());
uint32_t index = static_cast<uint32_t>(k->Number());
if (index < range) {
indices->push_back(index);
}
});
break;
}
#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) case TYPE##_ELEMENTS:
TYPED_ARRAYS(TYPED_ARRAY_CASE)
#undef TYPED_ARRAY_CASE
{
uint32_t length = static_cast<uint32_t>(
FixedArrayBase::cast(object->elements())->length());
if (range <= length) {
length = range;
// We will add all indices, so we might as well clear it first
// and avoid duplicates.
indices->clear();
}
for (uint32_t i = 0; i < length; i++) {
indices->push_back(i);
}
if (length == range) return; // All indices accounted for already.
break;
}
case FAST_SLOPPY_ARGUMENTS_ELEMENTS:
case SLOW_SLOPPY_ARGUMENTS_ELEMENTS: {
DisallowHeapAllocation no_gc;
FixedArrayBase* elements = object->elements();
JSObject* raw_object = *object;
ElementsAccessor* accessor = object->GetElementsAccessor();
for (uint32_t i = 0; i < range; i++) {
if (accessor->HasElement(raw_object, i, elements)) {
indices->push_back(i);
}
}
break;
}
case FAST_STRING_WRAPPER_ELEMENTS:
case SLOW_STRING_WRAPPER_ELEMENTS: {
DCHECK(object->IsJSValue());
Handle<JSValue> js_value = Handle<JSValue>::cast(object);
DCHECK(js_value->value()->IsString());
Handle<String> string(String::cast(js_value->value()), isolate);
uint32_t length = static_cast<uint32_t>(string->length());
uint32_t i = 0;
uint32_t limit = Min(length, range);
for (; i < limit; i++) {
indices->push_back(i);
}
ElementsAccessor* accessor = object->GetElementsAccessor();
for (; i < range; i++) {
if (accessor->HasElement(*object, i)) {
indices->push_back(i);
}
}
break;
}
case NO_ELEMENTS:
break;
}
PrototypeIterator iter(isolate, object);
if (!iter.IsAtEnd()) {
// The prototype will usually have no inherited element indices,
// but we have to check.
CollectElementIndices(PrototypeIterator::GetCurrent<JSObject>(iter), range,
indices);
}
}
bool IterateElementsSlow(Isolate* isolate, Handle<JSReceiver> receiver,
uint32_t length, ArrayConcatVisitor* visitor) {
FOR_WITH_HANDLE_SCOPE(isolate, uint32_t, i = 0, i, i < length, ++i, {
Maybe<bool> maybe = JSReceiver::HasElement(receiver, i);
if (!maybe.IsJust()) return false;
if (maybe.FromJust()) {
Handle<Object> element_value;
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate, element_value, JSReceiver::GetElement(isolate, receiver, i),
false);
if (!visitor->visit(i, element_value)) return false;
}
});
visitor->increase_index_offset(length);
return true;
}
/**
* A helper function that visits "array" elements of a JSReceiver in numerical
* order.
*
* The visitor argument called for each existing element in the array
* with the element index and the element's value.
* Afterwards it increments the base-index of the visitor by the array
* length.
* Returns false if any access threw an exception, otherwise true.
*/
bool IterateElements(Isolate* isolate, Handle<JSReceiver> receiver,
ArrayConcatVisitor* visitor) {
uint32_t length = 0;
if (receiver->IsJSArray()) {
Handle<JSArray> array = Handle<JSArray>::cast(receiver);
length = static_cast<uint32_t>(array->length()->Number());
} else {
Handle<Object> val;
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate, val, Object::GetLengthFromArrayLike(isolate, receiver), false);
// TODO(caitp): Support larger element indexes (up to 2^53-1).
if (!val->ToUint32(&length)) {
length = 0;
}
// TODO(cbruni): handle other element kind as well
return IterateElementsSlow(isolate, receiver, length, visitor);
}
if (!HasOnlySimpleElements(isolate, *receiver) ||
!visitor->has_simple_elements()) {
return IterateElementsSlow(isolate, receiver, length, visitor);
}
Handle<JSObject> array = Handle<JSObject>::cast(receiver);
switch (array->GetElementsKind()) {
case PACKED_SMI_ELEMENTS:
case PACKED_ELEMENTS:
case HOLEY_SMI_ELEMENTS:
case HOLEY_ELEMENTS: {
// Run through the elements FixedArray and use HasElement and GetElement
// to check the prototype for missing elements.
Handle<FixedArray> elements(FixedArray::cast(array->elements()));
int fast_length = static_cast<int>(length);
DCHECK(fast_length <= elements->length());
FOR_WITH_HANDLE_SCOPE(isolate, int, j = 0, j, j < fast_length, j++, {
Handle<Object> element_value(elements->get(j), isolate);
if (!element_value->IsTheHole(isolate)) {
if (!visitor->visit(j, element_value)) return false;
} else {
Maybe<bool> maybe = JSReceiver::HasElement(array, j);
if (!maybe.IsJust()) return false;
if (maybe.FromJust()) {
// Call GetElement on array, not its prototype, or getters won't
// have the correct receiver.
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate, element_value,
JSReceiver::GetElement(isolate, array, j), false);
if (!visitor->visit(j, element_value)) return false;
}
}
});
break;
}
case HOLEY_DOUBLE_ELEMENTS:
case PACKED_DOUBLE_ELEMENTS: {
// Empty array is FixedArray but not FixedDoubleArray.
if (length == 0) break;
// Run through the elements FixedArray and use HasElement and GetElement
// to check the prototype for missing elements.
if (array->elements()->IsFixedArray()) {
DCHECK(array->elements()->length() == 0);
break;
}
Handle<FixedDoubleArray> elements(
FixedDoubleArray::cast(array->elements()));
int fast_length = static_cast<int>(length);
DCHECK(fast_length <= elements->length());
FOR_WITH_HANDLE_SCOPE(isolate, int, j = 0, j, j < fast_length, j++, {
if (!elements->is_the_hole(j)) {
double double_value = elements->get_scalar(j);
Handle<Object> element_value =
isolate->factory()->NewNumber(double_value);
if (!visitor->visit(j, element_value)) return false;
} else {
Maybe<bool> maybe = JSReceiver::HasElement(array, j);
if (!maybe.IsJust()) return false;
if (maybe.FromJust()) {
// Call GetElement on array, not its prototype, or getters won't
// have the correct receiver.
Handle<Object> element_value;
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate, element_value,
JSReceiver::GetElement(isolate, array, j), false);
if (!visitor->visit(j, element_value)) return false;
}
}
});
break;
}
case DICTIONARY_ELEMENTS: {
Handle<SeededNumberDictionary> dict(array->element_dictionary());
std::vector<uint32_t> indices;
indices.reserve(dict->Capacity() / 2);
// Collect all indices in the object and the prototypes less
// than length. This might introduce duplicates in the indices list.
CollectElementIndices(array, length, &indices);
std::sort(indices.begin(), indices.end());
size_t n = indices.size();
FOR_WITH_HANDLE_SCOPE(isolate, size_t, j = 0, j, j < n, (void)0, {
uint32_t index = indices[j];
Handle<Object> element;
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate, element, JSReceiver::GetElement(isolate, array, index),
false);
if (!visitor->visit(index, element)) return false;
// Skip to next different index (i.e., omit duplicates).
do {
j++;
} while (j < n && indices[j] == index);
});
break;
}
case FAST_SLOPPY_ARGUMENTS_ELEMENTS:
case SLOW_SLOPPY_ARGUMENTS_ELEMENTS: {
FOR_WITH_HANDLE_SCOPE(
isolate, uint32_t, index = 0, index, index < length, index++, {
Handle<Object> element;
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate, element, JSReceiver::GetElement(isolate, array, index),
false);
if (!visitor->visit(index, element)) return false;
});
break;
}
case NO_ELEMENTS:
break;
#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) case TYPE##_ELEMENTS:
TYPED_ARRAYS(TYPED_ARRAY_CASE)
#undef TYPED_ARRAY_CASE
return IterateElementsSlow(isolate, receiver, length, visitor);
case FAST_STRING_WRAPPER_ELEMENTS:
case SLOW_STRING_WRAPPER_ELEMENTS:
// |array| is guaranteed to be an array or typed array.
UNREACHABLE();
break;
}
visitor->increase_index_offset(length);
return true;
}
static Maybe<bool> IsConcatSpreadable(Isolate* isolate, Handle<Object> obj) {
HandleScope handle_scope(isolate);
if (!obj->IsJSReceiver()) return Just(false);
if (!isolate->IsIsConcatSpreadableLookupChainIntact(JSReceiver::cast(*obj))) {
// Slow path if @@isConcatSpreadable has been used.
Handle<Symbol> key(isolate->factory()->is_concat_spreadable_symbol());
Handle<Object> value;
MaybeHandle<Object> maybeValue =
i::Runtime::GetObjectProperty(isolate, obj, key);
if (!maybeValue.ToHandle(&value)) return Nothing<bool>();
if (!value->IsUndefined(isolate)) return Just(value->BooleanValue());
}
return Object::IsArray(obj);
}
Object* Slow_ArrayConcat(BuiltinArguments* args, Handle<Object> species,
Isolate* isolate) {
int argument_count = args->length();
bool is_array_species = *species == isolate->context()->array_function();
// Pass 1: estimate the length and number of elements of the result.
// The actual length can be larger if any of the arguments have getters
// that mutate other arguments (but will otherwise be precise).
// The number of elements is precise if there are no inherited elements.
ElementsKind kind = PACKED_SMI_ELEMENTS;
uint32_t estimate_result_length = 0;
uint32_t estimate_nof = 0;
FOR_WITH_HANDLE_SCOPE(isolate, int, i = 0, i, i < argument_count, i++, {
Handle<Object> obj((*args)[i], isolate);
uint32_t length_estimate;
uint32_t element_estimate;
if (obj->IsJSArray()) {
Handle<JSArray> array(Handle<JSArray>::cast(obj));
length_estimate = static_cast<uint32_t>(array->length()->Number());
if (length_estimate != 0) {
ElementsKind array_kind =
GetPackedElementsKind(array->GetElementsKind());
kind = GetMoreGeneralElementsKind(kind, array_kind);
}
element_estimate = EstimateElementCount(array);
} else {
if (obj->IsHeapObject()) {
kind = GetMoreGeneralElementsKind(
kind, obj->IsNumber() ? PACKED_DOUBLE_ELEMENTS : PACKED_ELEMENTS);
}
length_estimate = 1;
element_estimate = 1;
}
// Avoid overflows by capping at kMaxElementCount.
if (JSObject::kMaxElementCount - estimate_result_length < length_estimate) {
estimate_result_length = JSObject::kMaxElementCount;
} else {
estimate_result_length += length_estimate;
}
if (JSObject::kMaxElementCount - estimate_nof < element_estimate) {
estimate_nof = JSObject::kMaxElementCount;
} else {
estimate_nof += element_estimate;
}
});
// If estimated number of elements is more than half of length, a
// fixed array (fast case) is more time and space-efficient than a
// dictionary.
bool fast_case = is_array_species &&
(estimate_nof * 2) >= estimate_result_length &&
isolate->IsIsConcatSpreadableLookupChainIntact();
if (fast_case && kind == PACKED_DOUBLE_ELEMENTS) {
Handle<FixedArrayBase> storage =
isolate->factory()->NewFixedDoubleArray(estimate_result_length);
int j = 0;
bool failure = false;
if (estimate_result_length > 0) {
Handle<FixedDoubleArray> double_storage =
Handle<FixedDoubleArray>::cast(storage);
for (int i = 0; i < argument_count; i++) {
Handle<Object> obj((*args)[i], isolate);
if (obj->IsSmi()) {
double_storage->set(j, Smi::ToInt(*obj));
j++;
} else if (obj->IsNumber()) {
double_storage->set(j, obj->Number());
j++;
} else {
DisallowHeapAllocation no_gc;
JSArray* array = JSArray::cast(*obj);
uint32_t length = static_cast<uint32_t>(array->length()->Number());
switch (array->GetElementsKind()) {
case HOLEY_DOUBLE_ELEMENTS:
case PACKED_DOUBLE_ELEMENTS: {
// Empty array is FixedArray but not FixedDoubleArray.
if (length == 0) break;
FixedDoubleArray* elements =
FixedDoubleArray::cast(array->elements());
for (uint32_t i = 0; i < length; i++) {
if (elements->is_the_hole(i)) {
// TODO(jkummerow/verwaest): We could be a bit more clever
// here: Check if there are no elements/getters on the
// prototype chain, and if so, allow creation of a holey
// result array.
// Same thing below (holey smi case).
failure = true;
break;
}
double double_value = elements->get_scalar(i);
double_storage->set(j, double_value);
j++;
}
break;
}
case HOLEY_SMI_ELEMENTS:
case PACKED_SMI_ELEMENTS: {
Object* the_hole = isolate->heap()->the_hole_value();
FixedArray* elements(FixedArray::cast(array->elements()));
for (uint32_t i = 0; i < length; i++) {
Object* element = elements->get(i);
if (element == the_hole) {
failure = true;
break;
}
int32_t int_value = Smi::ToInt(element);
double_storage->set(j, int_value);
j++;
}
break;
}
case HOLEY_ELEMENTS:
case PACKED_ELEMENTS:
case DICTIONARY_ELEMENTS:
case NO_ELEMENTS:
DCHECK_EQ(0u, length);
break;
default:
UNREACHABLE();
}
}
if (failure) break;
}
}
if (!failure) {
return *isolate->factory()->NewJSArrayWithElements(storage, kind, j);
}
// In case of failure, fall through.
}
Handle<HeapObject> storage;
if (fast_case) {
// The backing storage array must have non-existing elements to preserve
// holes across concat operations.
storage =
isolate->factory()->NewFixedArrayWithHoles(estimate_result_length);
} else if (is_array_species) {
storage = SeededNumberDictionary::New(isolate, estimate_nof);
} else {
DCHECK(species->IsConstructor());
Handle<Object> length(Smi::kZero, isolate);
Handle<Object> storage_object;
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
isolate, storage_object,
Execution::New(isolate, species, species, 1, &length));
storage = Handle<HeapObject>::cast(storage_object);
}
ArrayConcatVisitor visitor(isolate, storage, fast_case);
for (int i = 0; i < argument_count; i++) {
Handle<Object> obj((*args)[i], isolate);
Maybe<bool> spreadable = IsConcatSpreadable(isolate, obj);
MAYBE_RETURN(spreadable, isolate->heap()->exception());
if (spreadable.FromJust()) {
Handle<JSReceiver> object = Handle<JSReceiver>::cast(obj);
if (!IterateElements(isolate, object, &visitor)) {
return isolate->heap()->exception();
}
} else {
if (!visitor.visit(0, obj)) return isolate->heap()->exception();
visitor.increase_index_offset(1);
}
}
if (visitor.exceeds_array_limit()) {
THROW_NEW_ERROR_RETURN_FAILURE(
isolate, NewRangeError(MessageTemplate::kInvalidArrayLength));
}
if (is_array_species) {
return *visitor.ToArray();
} else {
RETURN_RESULT_OR_FAILURE(isolate, visitor.ToJSReceiver());
}
}
bool IsSimpleArray(Isolate* isolate, Handle<JSArray> obj) {
DisallowHeapAllocation no_gc;
Map* map = obj->map();
// If there is only the 'length' property we are fine.
if (map->prototype() ==
isolate->native_context()->initial_array_prototype() &&
map->NumberOfOwnDescriptors() == 1) {
return true;
}
// TODO(cbruni): slower lookup for array subclasses and support slow
// @@IsConcatSpreadable lookup.
return false;
}
MaybeHandle<JSArray> Fast_ArrayConcat(Isolate* isolate,
BuiltinArguments* args) {
if (!isolate->IsIsConcatSpreadableLookupChainIntact()) {
return MaybeHandle<JSArray>();
}
// We shouldn't overflow when adding another len.
const int kHalfOfMaxInt = 1 << (kBitsPerInt - 2);
STATIC_ASSERT(FixedArray::kMaxLength < kHalfOfMaxInt);
STATIC_ASSERT(FixedDoubleArray::kMaxLength < kHalfOfMaxInt);
USE(kHalfOfMaxInt);
int n_arguments = args->length();
int result_len = 0;
{
DisallowHeapAllocation no_gc;
// Iterate through all the arguments performing checks
// and calculating total length.
for (int i = 0; i < n_arguments; i++) {
Object* arg = (*args)[i];
if (!arg->IsJSArray()) return MaybeHandle<JSArray>();
if (!HasOnlySimpleReceiverElements(isolate, JSObject::cast(arg))) {
return MaybeHandle<JSArray>();
}
// TODO(cbruni): support fast concatenation of DICTIONARY_ELEMENTS.
if (!JSObject::cast(arg)->HasFastElements()) {
return MaybeHandle<JSArray>();
}
Handle<JSArray> array(JSArray::cast(arg), isolate);
if (!IsSimpleArray(isolate, array)) {
return MaybeHandle<JSArray>();
}
// The Array length is guaranted to be <= kHalfOfMaxInt thus we won't
// overflow.
result_len += Smi::ToInt(array->length());
DCHECK(result_len >= 0);
// Throw an Error if we overflow the FixedArray limits
if (FixedDoubleArray::kMaxLength < result_len ||
FixedArray::kMaxLength < result_len) {
AllowHeapAllocation gc;
THROW_NEW_ERROR(isolate,
NewRangeError(MessageTemplate::kInvalidArrayLength),
JSArray);
}
}
}
return ElementsAccessor::Concat(isolate, args, n_arguments, result_len);
}
} // namespace
// ES6 22.1.3.1 Array.prototype.concat
BUILTIN(ArrayConcat) {
HandleScope scope(isolate);
Handle<Object> receiver = args.receiver();
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
isolate, receiver,
Object::ToObject(isolate, args.receiver(), "Array.prototype.concat"));
args[0] = *receiver;
Handle<JSArray> result_array;
// Avoid a real species read to avoid extra lookups to the array constructor
if (V8_LIKELY(receiver->IsJSArray() &&
Handle<JSArray>::cast(receiver)->HasArrayPrototype(isolate) &&
isolate->IsArraySpeciesLookupChainIntact())) {
if (Fast_ArrayConcat(isolate, &args).ToHandle(&result_array)) {
return *result_array;
}
if (isolate->has_pending_exception()) return isolate->heap()->exception();
}
// Reading @@species happens before anything else with a side effect, so
// we can do it here to determine whether to take the fast path.
Handle<Object> species;
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
isolate, species, Object::ArraySpeciesConstructor(isolate, receiver));
if (*species == *isolate->array_function()) {
if (Fast_ArrayConcat(isolate, &args).ToHandle(&result_array)) {
return *result_array;
}
if (isolate->has_pending_exception()) return isolate->heap()->exception();
}
return Slow_ArrayConcat(&args, species, isolate);
}
} // namespace internal
} // namespace v8