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v8/src/elements.cc

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// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "v8.h"
#include "arguments.h"
#include "objects.h"
#include "elements.h"
#include "utils.h"
#include "v8conversions.h"
// Each concrete ElementsAccessor can handle exactly one ElementsKind,
// several abstract ElementsAccessor classes are used to allow sharing
// common code.
//
// Inheritance hierarchy:
// - ElementsAccessorBase (abstract)
// - FastElementsAccessor (abstract)
// - FastSmiOrObjectElementsAccessor
// - FastPackedSmiElementsAccessor
// - FastHoleySmiElementsAccessor
// - FastPackedObjectElementsAccessor
// - FastHoleyObjectElementsAccessor
// - FastDoubleElementsAccessor
// - FastPackedDoubleElementsAccessor
// - FastHoleyDoubleElementsAccessor
// - TypedElementsAccessor: template, with instantiations:
// - ExternalInt8ElementsAccessor
// - ExternalUint8ElementsAccessor
// - ExternalInt16ElementsAccessor
// - ExternalUint16ElementsAccessor
// - ExternalInt32ElementsAccessor
// - ExternalUint32ElementsAccessor
// - ExternalFloat32ElementsAccessor
// - ExternalFloat64ElementsAccessor
// - ExternalUint8ClampedElementsAccessor
// - FixedUint8ElementsAccessor
// - FixedInt8ElementsAccessor
// - FixedUint16ElementsAccessor
// - FixedInt16ElementsAccessor
// - FixedUint32ElementsAccessor
// - FixedInt32ElementsAccessor
// - FixedFloat32ElementsAccessor
// - FixedFloat64ElementsAccessor
// - FixedUint8ClampedElementsAccessor
// - DictionaryElementsAccessor
// - SloppyArgumentsElementsAccessor
namespace v8 {
namespace internal {
static const int kPackedSizeNotKnown = -1;
// First argument in list is the accessor class, the second argument is the
// accessor ElementsKind, and the third is the backing store class. Use the
// fast element handler for smi-only arrays. The implementation is currently
// identical. Note that the order must match that of the ElementsKind enum for
// the |accessor_array[]| below to work.
#define ELEMENTS_LIST(V) \
V(FastPackedSmiElementsAccessor, FAST_SMI_ELEMENTS, FixedArray) \
V(FastHoleySmiElementsAccessor, FAST_HOLEY_SMI_ELEMENTS, \
FixedArray) \
V(FastPackedObjectElementsAccessor, FAST_ELEMENTS, FixedArray) \
V(FastHoleyObjectElementsAccessor, FAST_HOLEY_ELEMENTS, FixedArray) \
V(FastPackedDoubleElementsAccessor, FAST_DOUBLE_ELEMENTS, \
FixedDoubleArray) \
V(FastHoleyDoubleElementsAccessor, FAST_HOLEY_DOUBLE_ELEMENTS, \
FixedDoubleArray) \
V(DictionaryElementsAccessor, DICTIONARY_ELEMENTS, \
SeededNumberDictionary) \
V(SloppyArgumentsElementsAccessor, SLOPPY_ARGUMENTS_ELEMENTS, \
FixedArray) \
V(ExternalInt8ElementsAccessor, EXTERNAL_INT8_ELEMENTS, \
ExternalInt8Array) \
V(ExternalUint8ElementsAccessor, \
EXTERNAL_UINT8_ELEMENTS, ExternalUint8Array) \
V(ExternalInt16ElementsAccessor, EXTERNAL_INT16_ELEMENTS, \
ExternalInt16Array) \
V(ExternalUint16ElementsAccessor, \
EXTERNAL_UINT16_ELEMENTS, ExternalUint16Array) \
V(ExternalInt32ElementsAccessor, EXTERNAL_INT32_ELEMENTS, \
ExternalInt32Array) \
V(ExternalUint32ElementsAccessor, \
EXTERNAL_UINT32_ELEMENTS, ExternalUint32Array) \
V(ExternalFloat32ElementsAccessor, \
EXTERNAL_FLOAT32_ELEMENTS, ExternalFloat32Array) \
V(ExternalFloat64ElementsAccessor, \
EXTERNAL_FLOAT64_ELEMENTS, ExternalFloat64Array) \
V(ExternalUint8ClampedElementsAccessor, \
EXTERNAL_UINT8_CLAMPED_ELEMENTS, \
ExternalUint8ClampedArray) \
V(FixedUint8ElementsAccessor, UINT8_ELEMENTS, FixedUint8Array) \
V(FixedInt8ElementsAccessor, INT8_ELEMENTS, FixedInt8Array) \
V(FixedUint16ElementsAccessor, UINT16_ELEMENTS, FixedUint16Array) \
V(FixedInt16ElementsAccessor, INT16_ELEMENTS, FixedInt16Array) \
V(FixedUint32ElementsAccessor, UINT32_ELEMENTS, FixedUint32Array) \
V(FixedInt32ElementsAccessor, INT32_ELEMENTS, FixedInt32Array) \
V(FixedFloat32ElementsAccessor, FLOAT32_ELEMENTS, FixedFloat32Array) \
V(FixedFloat64ElementsAccessor, FLOAT64_ELEMENTS, FixedFloat64Array) \
V(FixedUint8ClampedElementsAccessor, UINT8_CLAMPED_ELEMENTS, \
FixedUint8ClampedArray)
template<ElementsKind Kind> class ElementsKindTraits {
public:
typedef FixedArrayBase BackingStore;
};
#define ELEMENTS_TRAITS(Class, KindParam, Store) \
template<> class ElementsKindTraits<KindParam> { \
public: \
static const ElementsKind Kind = KindParam; \
typedef Store BackingStore; \
};
ELEMENTS_LIST(ELEMENTS_TRAITS)
#undef ELEMENTS_TRAITS
ElementsAccessor** ElementsAccessor::elements_accessors_;
static bool HasKey(FixedArray* array, Object* key) {
int len0 = array->length();
for (int i = 0; i < len0; i++) {
Object* element = array->get(i);
if (element->IsSmi() && element == key) return true;
if (element->IsString() &&
key->IsString() && String::cast(element)->Equals(String::cast(key))) {
return true;
}
}
return false;
}
static Handle<Object> ThrowArrayLengthRangeError(Isolate* isolate) {
isolate->Throw(
*isolate->factory()->NewRangeError("invalid_array_length",
HandleVector<Object>(NULL, 0)));
return Handle<Object>();
}
static void CopyObjectToObjectElements(FixedArrayBase* from_base,
ElementsKind from_kind,
uint32_t from_start,
FixedArrayBase* to_base,
ElementsKind to_kind,
uint32_t to_start,
int raw_copy_size) {
ASSERT(to_base->map() !=
from_base->GetIsolate()->heap()->fixed_cow_array_map());
DisallowHeapAllocation no_allocation;
int copy_size = raw_copy_size;
if (raw_copy_size < 0) {
ASSERT(raw_copy_size == ElementsAccessor::kCopyToEnd ||
raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole);
copy_size = Min(from_base->length() - from_start,
to_base->length() - to_start);
if (raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole) {
int start = to_start + copy_size;
int length = to_base->length() - start;
if (length > 0) {
Heap* heap = from_base->GetHeap();
MemsetPointer(FixedArray::cast(to_base)->data_start() + start,
heap->the_hole_value(), length);
}
}
}
ASSERT((copy_size + static_cast<int>(to_start)) <= to_base->length() &&
(copy_size + static_cast<int>(from_start)) <= from_base->length());
if (copy_size == 0) return;
FixedArray* from = FixedArray::cast(from_base);
FixedArray* to = FixedArray::cast(to_base);
ASSERT(IsFastSmiOrObjectElementsKind(from_kind));
ASSERT(IsFastSmiOrObjectElementsKind(to_kind));
Address to_address = to->address() + FixedArray::kHeaderSize;
Address from_address = from->address() + FixedArray::kHeaderSize;
CopyWords(reinterpret_cast<Object**>(to_address) + to_start,
reinterpret_cast<Object**>(from_address) + from_start,
static_cast<size_t>(copy_size));
if (IsFastObjectElementsKind(from_kind) &&
IsFastObjectElementsKind(to_kind)) {
Heap* heap = from->GetHeap();
if (!heap->InNewSpace(to)) {
heap->RecordWrites(to->address(),
to->OffsetOfElementAt(to_start),
copy_size);
}
heap->incremental_marking()->RecordWrites(to);
}
}
static void CopyDictionaryToObjectElements(FixedArrayBase* from_base,
uint32_t from_start,
FixedArrayBase* to_base,
ElementsKind to_kind,
uint32_t to_start,
int raw_copy_size) {
SeededNumberDictionary* from = SeededNumberDictionary::cast(from_base);
DisallowHeapAllocation no_allocation;
int copy_size = raw_copy_size;
Heap* heap = from->GetHeap();
if (raw_copy_size < 0) {
ASSERT(raw_copy_size == ElementsAccessor::kCopyToEnd ||
raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole);
copy_size = from->max_number_key() + 1 - from_start;
if (raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole) {
int start = to_start + copy_size;
int length = to_base->length() - start;
if (length > 0) {
Heap* heap = from->GetHeap();
MemsetPointer(FixedArray::cast(to_base)->data_start() + start,
heap->the_hole_value(), length);
}
}
}
ASSERT(to_base != from_base);
ASSERT(IsFastSmiOrObjectElementsKind(to_kind));
if (copy_size == 0) return;
FixedArray* to = FixedArray::cast(to_base);
uint32_t to_length = to->length();
if (to_start + copy_size > to_length) {
copy_size = to_length - to_start;
}
for (int i = 0; i < copy_size; i++) {
int entry = from->FindEntry(i + from_start);
if (entry != SeededNumberDictionary::kNotFound) {
Object* value = from->ValueAt(entry);
ASSERT(!value->IsTheHole());
to->set(i + to_start, value, SKIP_WRITE_BARRIER);
} else {
to->set_the_hole(i + to_start);
}
}
if (IsFastObjectElementsKind(to_kind)) {
if (!heap->InNewSpace(to)) {
heap->RecordWrites(to->address(),
to->OffsetOfElementAt(to_start),
copy_size);
}
heap->incremental_marking()->RecordWrites(to);
}
}
MUST_USE_RESULT static MaybeObject* CopyDoubleToObjectElements(
FixedArrayBase* from_base,
uint32_t from_start,
FixedArrayBase* to_base,
ElementsKind to_kind,
uint32_t to_start,
int raw_copy_size) {
ASSERT(IsFastSmiOrObjectElementsKind(to_kind));
int copy_size = raw_copy_size;
if (raw_copy_size < 0) {
ASSERT(raw_copy_size == ElementsAccessor::kCopyToEnd ||
raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole);
copy_size = Min(from_base->length() - from_start,
to_base->length() - to_start);
if (raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole) {
// Also initialize the area that will be copied over since HeapNumber
// allocation below can cause an incremental marking step, requiring all
// existing heap objects to be propertly initialized.
int start = to_start;
int length = to_base->length() - start;
if (length > 0) {
Heap* heap = from_base->GetHeap();
MemsetPointer(FixedArray::cast(to_base)->data_start() + start,
heap->the_hole_value(), length);
}
}
}
ASSERT((copy_size + static_cast<int>(to_start)) <= to_base->length() &&
(copy_size + static_cast<int>(from_start)) <= from_base->length());
if (copy_size == 0) return from_base;
FixedDoubleArray* from = FixedDoubleArray::cast(from_base);
FixedArray* to = FixedArray::cast(to_base);
for (int i = 0; i < copy_size; ++i) {
if (IsFastSmiElementsKind(to_kind)) {
UNIMPLEMENTED();
return Failure::Exception();
} else {
MaybeObject* maybe_value = from->get(i + from_start);
Object* value;
ASSERT(IsFastObjectElementsKind(to_kind));
// Because Double -> Object elements transitions allocate HeapObjects
// iteratively, the allocate must succeed within a single GC cycle,
// otherwise the retry after the GC will also fail. In order to ensure
// that no GC is triggered, allocate HeapNumbers from old space if they
// can't be taken from new space.
if (!maybe_value->ToObject(&value)) {
ASSERT(maybe_value->IsRetryAfterGC());
Heap* heap = from->GetHeap();
MaybeObject* maybe_value_object =
heap->AllocateHeapNumber(from->get_scalar(i + from_start),
TENURED);
if (!maybe_value_object->ToObject(&value)) return maybe_value_object;
}
to->set(i + to_start, value, UPDATE_WRITE_BARRIER);
}
}
return to;
}
static void CopyDoubleToDoubleElements(FixedArrayBase* from_base,
uint32_t from_start,
FixedArrayBase* to_base,
uint32_t to_start,
int raw_copy_size) {
int copy_size = raw_copy_size;
if (raw_copy_size < 0) {
ASSERT(raw_copy_size == ElementsAccessor::kCopyToEnd ||
raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole);
copy_size = Min(from_base->length() - from_start,
to_base->length() - to_start);
if (raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole) {
for (int i = to_start + copy_size; i < to_base->length(); ++i) {
FixedDoubleArray::cast(to_base)->set_the_hole(i);
}
}
}
ASSERT((copy_size + static_cast<int>(to_start)) <= to_base->length() &&
(copy_size + static_cast<int>(from_start)) <= from_base->length());
if (copy_size == 0) return;
FixedDoubleArray* from = FixedDoubleArray::cast(from_base);
FixedDoubleArray* to = FixedDoubleArray::cast(to_base);
Address to_address = to->address() + FixedDoubleArray::kHeaderSize;
Address from_address = from->address() + FixedDoubleArray::kHeaderSize;
to_address += kDoubleSize * to_start;
from_address += kDoubleSize * from_start;
int words_per_double = (kDoubleSize / kPointerSize);
CopyWords(reinterpret_cast<Object**>(to_address),
reinterpret_cast<Object**>(from_address),
static_cast<size_t>(words_per_double * copy_size));
}
static void CopySmiToDoubleElements(FixedArrayBase* from_base,
uint32_t from_start,
FixedArrayBase* to_base,
uint32_t to_start,
int raw_copy_size) {
int copy_size = raw_copy_size;
if (raw_copy_size < 0) {
ASSERT(raw_copy_size == ElementsAccessor::kCopyToEnd ||
raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole);
copy_size = from_base->length() - from_start;
if (raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole) {
for (int i = to_start + copy_size; i < to_base->length(); ++i) {
FixedDoubleArray::cast(to_base)->set_the_hole(i);
}
}
}
ASSERT((copy_size + static_cast<int>(to_start)) <= to_base->length() &&
(copy_size + static_cast<int>(from_start)) <= from_base->length());
if (copy_size == 0) return;
FixedArray* from = FixedArray::cast(from_base);
FixedDoubleArray* to = FixedDoubleArray::cast(to_base);
Object* the_hole = from->GetHeap()->the_hole_value();
for (uint32_t from_end = from_start + static_cast<uint32_t>(copy_size);
from_start < from_end; from_start++, to_start++) {
Object* hole_or_smi = from->get(from_start);
if (hole_or_smi == the_hole) {
to->set_the_hole(to_start);
} else {
to->set(to_start, Smi::cast(hole_or_smi)->value());
}
}
}
static void CopyPackedSmiToDoubleElements(FixedArrayBase* from_base,
uint32_t from_start,
FixedArrayBase* to_base,
uint32_t to_start,
int packed_size,
int raw_copy_size) {
int copy_size = raw_copy_size;
uint32_t to_end;
if (raw_copy_size < 0) {
ASSERT(raw_copy_size == ElementsAccessor::kCopyToEnd ||
raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole);
copy_size = packed_size - from_start;
if (raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole) {
to_end = to_base->length();
for (uint32_t i = to_start + copy_size; i < to_end; ++i) {
FixedDoubleArray::cast(to_base)->set_the_hole(i);
}
} else {
to_end = to_start + static_cast<uint32_t>(copy_size);
}
} else {
to_end = to_start + static_cast<uint32_t>(copy_size);
}
ASSERT(static_cast<int>(to_end) <= to_base->length());
ASSERT(packed_size >= 0 && packed_size <= copy_size);
ASSERT((copy_size + static_cast<int>(to_start)) <= to_base->length() &&
(copy_size + static_cast<int>(from_start)) <= from_base->length());
if (copy_size == 0) return;
FixedArray* from = FixedArray::cast(from_base);
FixedDoubleArray* to = FixedDoubleArray::cast(to_base);
for (uint32_t from_end = from_start + static_cast<uint32_t>(packed_size);
from_start < from_end; from_start++, to_start++) {
Object* smi = from->get(from_start);
ASSERT(!smi->IsTheHole());
to->set(to_start, Smi::cast(smi)->value());
}
}
static void CopyObjectToDoubleElements(FixedArrayBase* from_base,
uint32_t from_start,
FixedArrayBase* to_base,
uint32_t to_start,
int raw_copy_size) {
int copy_size = raw_copy_size;
if (raw_copy_size < 0) {
ASSERT(raw_copy_size == ElementsAccessor::kCopyToEnd ||
raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole);
copy_size = from_base->length() - from_start;
if (raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole) {
for (int i = to_start + copy_size; i < to_base->length(); ++i) {
FixedDoubleArray::cast(to_base)->set_the_hole(i);
}
}
}
ASSERT((copy_size + static_cast<int>(to_start)) <= to_base->length() &&
(copy_size + static_cast<int>(from_start)) <= from_base->length());
if (copy_size == 0) return;
FixedArray* from = FixedArray::cast(from_base);
FixedDoubleArray* to = FixedDoubleArray::cast(to_base);
Object* the_hole = from->GetHeap()->the_hole_value();
for (uint32_t from_end = from_start + copy_size;
from_start < from_end; from_start++, to_start++) {
Object* hole_or_object = from->get(from_start);
if (hole_or_object == the_hole) {
to->set_the_hole(to_start);
} else {
to->set(to_start, hole_or_object->Number());
}
}
}
static void CopyDictionaryToDoubleElements(FixedArrayBase* from_base,
uint32_t from_start,
FixedArrayBase* to_base,
uint32_t to_start,
int raw_copy_size) {
SeededNumberDictionary* from = SeededNumberDictionary::cast(from_base);
int copy_size = raw_copy_size;
if (copy_size < 0) {
ASSERT(copy_size == ElementsAccessor::kCopyToEnd ||
copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole);
copy_size = from->max_number_key() + 1 - from_start;
if (raw_copy_size == ElementsAccessor::kCopyToEndAndInitializeToHole) {
for (int i = to_start + copy_size; i < to_base->length(); ++i) {
FixedDoubleArray::cast(to_base)->set_the_hole(i);
}
}
}
if (copy_size == 0) return;
FixedDoubleArray* to = FixedDoubleArray::cast(to_base);
uint32_t to_length = to->length();
if (to_start + copy_size > to_length) {
copy_size = to_length - to_start;
}
for (int i = 0; i < copy_size; i++) {
int entry = from->FindEntry(i + from_start);
if (entry != SeededNumberDictionary::kNotFound) {
to->set(i + to_start, from->ValueAt(entry)->Number());
} else {
to->set_the_hole(i + to_start);
}
}
}
static void TraceTopFrame(Isolate* isolate) {
StackFrameIterator it(isolate);
if (it.done()) {
PrintF("unknown location (no JavaScript frames present)");
return;
}
StackFrame* raw_frame = it.frame();
if (raw_frame->is_internal()) {
Code* apply_builtin = isolate->builtins()->builtin(
Builtins::kFunctionApply);
if (raw_frame->unchecked_code() == apply_builtin) {
PrintF("apply from ");
it.Advance();
raw_frame = it.frame();
}
}
JavaScriptFrame::PrintTop(isolate, stdout, false, true);
}
void CheckArrayAbuse(JSObject* obj, const char* op, uint32_t key,
bool allow_appending) {
Object* raw_length = NULL;
const char* elements_type = "array";
if (obj->IsJSArray()) {
JSArray* array = JSArray::cast(obj);
raw_length = array->length();
} else {
raw_length = Smi::FromInt(obj->elements()->length());
elements_type = "object";
}
if (raw_length->IsNumber()) {
double n = raw_length->Number();
if (FastI2D(FastD2UI(n)) == n) {
int32_t int32_length = DoubleToInt32(n);
uint32_t compare_length = static_cast<uint32_t>(int32_length);
if (allow_appending) compare_length++;
if (key >= compare_length) {
PrintF("[OOB %s %s (%s length = %d, element accessed = %d) in ",
elements_type, op, elements_type,
static_cast<int>(int32_length),
static_cast<int>(key));
TraceTopFrame(obj->GetIsolate());
PrintF("]\n");
}
} else {
PrintF("[%s elements length not integer value in ", elements_type);
TraceTopFrame(obj->GetIsolate());
PrintF("]\n");
}
} else {
PrintF("[%s elements length not a number in ", elements_type);
TraceTopFrame(obj->GetIsolate());
PrintF("]\n");
}
}
// Base class for element handler implementations. Contains the
// the common logic for objects with different ElementsKinds.
// Subclasses must specialize method for which the element
// implementation differs from the base class implementation.
//
// This class is intended to be used in the following way:
//
// class SomeElementsAccessor :
// public ElementsAccessorBase<SomeElementsAccessor,
// BackingStoreClass> {
// ...
// }
//
// This is an example of the Curiously Recurring Template Pattern (see
// http://en.wikipedia.org/wiki/Curiously_recurring_template_pattern). We use
// CRTP to guarantee aggressive compile time optimizations (i.e. inlining and
// specialization of SomeElementsAccessor methods).
template <typename ElementsAccessorSubclass,
typename ElementsTraitsParam>
class ElementsAccessorBase : public ElementsAccessor {
protected:
explicit ElementsAccessorBase(const char* name)
: ElementsAccessor(name) { }
typedef ElementsTraitsParam ElementsTraits;
typedef typename ElementsTraitsParam::BackingStore BackingStore;
virtual ElementsKind kind() const V8_FINAL V8_OVERRIDE {
return ElementsTraits::Kind;
}
static void ValidateContents(JSObject* holder, int length) {
}
static void ValidateImpl(JSObject* holder) {
FixedArrayBase* fixed_array_base = holder->elements();
// When objects are first allocated, its elements are Failures.
if (fixed_array_base->IsFailure()) return;
if (!fixed_array_base->IsHeapObject()) return;
// Arrays that have been shifted in place can't be verified.
if (fixed_array_base->IsFiller()) return;
int length = 0;
if (holder->IsJSArray()) {
Object* length_obj = JSArray::cast(holder)->length();
if (length_obj->IsSmi()) {
length = Smi::cast(length_obj)->value();
}
} else {
length = fixed_array_base->length();
}
ElementsAccessorSubclass::ValidateContents(holder, length);
}
virtual void Validate(JSObject* holder) V8_FINAL V8_OVERRIDE {
ElementsAccessorSubclass::ValidateImpl(holder);
}
static bool HasElementImpl(Object* receiver,
JSObject* holder,
uint32_t key,
FixedArrayBase* backing_store) {
return ElementsAccessorSubclass::GetAttributesImpl(
receiver, holder, key, backing_store) != ABSENT;
}
virtual bool HasElement(Object* receiver,
JSObject* holder,
uint32_t key,
FixedArrayBase* backing_store) V8_FINAL V8_OVERRIDE {
if (backing_store == NULL) {
backing_store = holder->elements();
}
return ElementsAccessorSubclass::HasElementImpl(
receiver, holder, key, backing_store);
}
// TODO(ishell): Temporary wrapper until handlified.
MUST_USE_RESULT virtual Handle<Object> Get(
Handle<Object> receiver,
Handle<JSObject> holder,
uint32_t key,
Handle<FixedArrayBase> backing_store) V8_FINAL V8_OVERRIDE {
CALL_HEAP_FUNCTION(holder->GetIsolate(),
Get(*receiver, *holder, key,
backing_store.is_null()
? NULL : *backing_store),
Object);
}
MUST_USE_RESULT virtual MaybeObject* Get(
Object* receiver,
JSObject* holder,
uint32_t key,
FixedArrayBase* backing_store) V8_FINAL V8_OVERRIDE {
if (backing_store == NULL) {
backing_store = holder->elements();
}
if (!IsExternalArrayElementsKind(ElementsTraits::Kind) &&
FLAG_trace_js_array_abuse) {
CheckArrayAbuse(holder, "elements read", key);
}
if (IsExternalArrayElementsKind(ElementsTraits::Kind) &&
FLAG_trace_external_array_abuse) {
CheckArrayAbuse(holder, "external elements read", key);
}
return ElementsAccessorSubclass::GetImpl(
receiver, holder, key, backing_store);
}
MUST_USE_RESULT static MaybeObject* GetImpl(Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* backing_store) {
return (key < ElementsAccessorSubclass::GetCapacityImpl(backing_store))
? BackingStore::cast(backing_store)->get(key)
: backing_store->GetHeap()->the_hole_value();
}
MUST_USE_RESULT virtual PropertyAttributes GetAttributes(
Object* receiver,
JSObject* holder,
uint32_t key,
FixedArrayBase* backing_store) V8_FINAL V8_OVERRIDE {
if (backing_store == NULL) {
backing_store = holder->elements();
}
return ElementsAccessorSubclass::GetAttributesImpl(
receiver, holder, key, backing_store);
}
MUST_USE_RESULT static PropertyAttributes GetAttributesImpl(
Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* backing_store) {
if (key >= ElementsAccessorSubclass::GetCapacityImpl(backing_store)) {
return ABSENT;
}
return BackingStore::cast(backing_store)->is_the_hole(key) ? ABSENT : NONE;
}
MUST_USE_RESULT virtual PropertyType GetType(
Object* receiver,
JSObject* holder,
uint32_t key,
FixedArrayBase* backing_store) V8_FINAL V8_OVERRIDE {
if (backing_store == NULL) {
backing_store = holder->elements();
}
return ElementsAccessorSubclass::GetTypeImpl(
receiver, holder, key, backing_store);
}
MUST_USE_RESULT static PropertyType GetTypeImpl(
Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* backing_store) {
if (key >= ElementsAccessorSubclass::GetCapacityImpl(backing_store)) {
return NONEXISTENT;
}
return BackingStore::cast(backing_store)->is_the_hole(key)
? NONEXISTENT : FIELD;
}
MUST_USE_RESULT virtual AccessorPair* GetAccessorPair(
Object* receiver,
JSObject* holder,
uint32_t key,
FixedArrayBase* backing_store) V8_FINAL V8_OVERRIDE {
if (backing_store == NULL) {
backing_store = holder->elements();
}
return ElementsAccessorSubclass::GetAccessorPairImpl(
receiver, holder, key, backing_store);
}
MUST_USE_RESULT static AccessorPair* GetAccessorPairImpl(
Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* backing_store) {
return NULL;
}
MUST_USE_RESULT virtual Handle<Object> SetLength(
Handle<JSArray> array,
Handle<Object> length) V8_FINAL V8_OVERRIDE {
Isolate* isolate = array->GetIsolate();
return ElementsAccessorSubclass::SetLengthImpl(
array, length, handle(array->elements(), isolate));
}
MUST_USE_RESULT static Handle<Object> SetLengthImpl(
Handle<JSObject> obj,
Handle<Object> length,
Handle<FixedArrayBase> backing_store);
MUST_USE_RESULT virtual MaybeObject* SetCapacityAndLength(
JSArray* array,
int capacity,
int length) V8_FINAL V8_OVERRIDE {
return ElementsAccessorSubclass::SetFastElementsCapacityAndLength(
array,
capacity,
length);
}
MUST_USE_RESULT static MaybeObject* SetFastElementsCapacityAndLength(
JSObject* obj,
int capacity,
int length) {
UNIMPLEMENTED();
return obj;
}
// TODO(ishell): Temporary wrapper until handlified.
MUST_USE_RESULT static Handle<Object> SetFastElementsCapacityAndLength(
Handle<JSObject> obj,
int capacity,
int length) {
CALL_HEAP_FUNCTION(obj->GetIsolate(),
SetFastElementsCapacityAndLength(*obj, capacity, length),
Object);
}
MUST_USE_RESULT virtual Handle<Object> Delete(
Handle<JSObject> obj,
uint32_t key,
JSReceiver::DeleteMode mode) V8_OVERRIDE = 0;
MUST_USE_RESULT static MaybeObject* CopyElementsImpl(FixedArrayBase* from,
uint32_t from_start,
FixedArrayBase* to,
ElementsKind from_kind,
uint32_t to_start,
int packed_size,
int copy_size) {
UNREACHABLE();
return NULL;
}
// TODO(ishell): Temporary wrapper, remove when CopyElements handlified.
Handle<Object> CopyElementsHelper(
Handle<JSObject> from_holder,
uint32_t from_start,
ElementsKind from_kind,
Handle<FixedArrayBase> to,
uint32_t to_start,
int copy_size,
Handle<FixedArrayBase> from) {
CALL_HEAP_FUNCTION(to->GetIsolate(),
CopyElements(
from_holder.is_null() ? NULL : *from_holder,
from_start, from_kind, *to, to_start, copy_size,
from.is_null() ? NULL : *from),
Object);
}
virtual void CopyElements(
Handle<JSObject> from_holder,
uint32_t from_start,
ElementsKind from_kind,
Handle<FixedArrayBase> to,
uint32_t to_start,
int copy_size,
Handle<FixedArrayBase> from) V8_FINAL V8_OVERRIDE {
Handle<Object> result = CopyElementsHelper(
from_holder, from_start, from_kind, to, to_start, copy_size, from);
ASSERT(!result.is_null());
USE(result);
}
MUST_USE_RESULT virtual MaybeObject* CopyElements(
JSObject* from_holder,
uint32_t from_start,
ElementsKind from_kind,
FixedArrayBase* to,
uint32_t to_start,
int copy_size,
FixedArrayBase* from) V8_FINAL V8_OVERRIDE {
int packed_size = kPackedSizeNotKnown;
if (from == NULL) {
from = from_holder->elements();
}
if (from_holder) {
bool is_packed = IsFastPackedElementsKind(from_kind) &&
from_holder->IsJSArray();
if (is_packed) {
packed_size = Smi::cast(JSArray::cast(from_holder)->length())->value();
if (copy_size >= 0 && packed_size > copy_size) {
packed_size = copy_size;
}
}
}
return ElementsAccessorSubclass::CopyElementsImpl(
from, from_start, to, from_kind, to_start, packed_size, copy_size);
}
MUST_USE_RESULT virtual MaybeObject* AddElementsToFixedArray(
Object* receiver,
JSObject* holder,
FixedArray* to,
FixedArrayBase* from) V8_FINAL V8_OVERRIDE {
int len0 = to->length();
#ifdef ENABLE_SLOW_ASSERTS
if (FLAG_enable_slow_asserts) {
for (int i = 0; i < len0; i++) {
ASSERT(!to->get(i)->IsTheHole());
}
}
#endif
if (from == NULL) {
from = holder->elements();
}
// Optimize if 'other' is empty.
// We cannot optimize if 'this' is empty, as other may have holes.
uint32_t len1 = ElementsAccessorSubclass::GetCapacityImpl(from);
if (len1 == 0) return to;
// Compute how many elements are not in other.
uint32_t extra = 0;
for (uint32_t y = 0; y < len1; y++) {
uint32_t key = ElementsAccessorSubclass::GetKeyForIndexImpl(from, y);
if (ElementsAccessorSubclass::HasElementImpl(
receiver, holder, key, from)) {
MaybeObject* maybe_value =
ElementsAccessorSubclass::GetImpl(receiver, holder, key, from);
Object* value;
if (!maybe_value->To(&value)) return maybe_value;
ASSERT(!value->IsTheHole());
if (!HasKey(to, value)) {
extra++;
}
}
}
if (extra == 0) return to;
// Allocate the result
FixedArray* result;
MaybeObject* maybe_obj = from->GetHeap()->AllocateFixedArray(len0 + extra);
if (!maybe_obj->To(&result)) return maybe_obj;
// Fill in the content
{
DisallowHeapAllocation no_gc;
WriteBarrierMode mode = result->GetWriteBarrierMode(no_gc);
for (int i = 0; i < len0; i++) {
Object* e = to->get(i);
ASSERT(e->IsString() || e->IsNumber());
result->set(i, e, mode);
}
}
// Fill in the extra values.
uint32_t index = 0;
for (uint32_t y = 0; y < len1; y++) {
uint32_t key =
ElementsAccessorSubclass::GetKeyForIndexImpl(from, y);
if (ElementsAccessorSubclass::HasElementImpl(
receiver, holder, key, from)) {
MaybeObject* maybe_value =
ElementsAccessorSubclass::GetImpl(receiver, holder, key, from);
Object* value;
if (!maybe_value->To(&value)) return maybe_value;
if (!value->IsTheHole() && !HasKey(to, value)) {
result->set(len0 + index, value);
index++;
}
}
}
ASSERT(extra == index);
return result;
}
protected:
static uint32_t GetCapacityImpl(FixedArrayBase* backing_store) {
return backing_store->length();
}
virtual uint32_t GetCapacity(FixedArrayBase* backing_store)
V8_FINAL V8_OVERRIDE {
return ElementsAccessorSubclass::GetCapacityImpl(backing_store);
}
static uint32_t GetKeyForIndexImpl(FixedArrayBase* backing_store,
uint32_t index) {
return index;
}
virtual uint32_t GetKeyForIndex(FixedArrayBase* backing_store,
uint32_t index) V8_FINAL V8_OVERRIDE {
return ElementsAccessorSubclass::GetKeyForIndexImpl(backing_store, index);
}
private:
DISALLOW_COPY_AND_ASSIGN(ElementsAccessorBase);
};
// Super class for all fast element arrays.
template<typename FastElementsAccessorSubclass,
typename KindTraits,
int ElementSize>
class FastElementsAccessor
: public ElementsAccessorBase<FastElementsAccessorSubclass, KindTraits> {
public:
explicit FastElementsAccessor(const char* name)
: ElementsAccessorBase<FastElementsAccessorSubclass,
KindTraits>(name) {}
protected:
friend class ElementsAccessorBase<FastElementsAccessorSubclass, KindTraits>;
friend class SloppyArgumentsElementsAccessor;
typedef typename KindTraits::BackingStore BackingStore;
// Adjusts the length of the fast backing store or returns the new length or
// undefined in case conversion to a slow backing store should be performed.
static Handle<Object> SetLengthWithoutNormalize(
Handle<FixedArrayBase> backing_store,
Handle<JSArray> array,
Handle<Object> length_object,
uint32_t length) {
Isolate* isolate = array->GetIsolate();
uint32_t old_capacity = backing_store->length();
Handle<Object> old_length(array->length(), isolate);
bool same_or_smaller_size = old_length->IsSmi() &&
static_cast<uint32_t>(Handle<Smi>::cast(old_length)->value()) >= length;
ElementsKind kind = array->GetElementsKind();
if (!same_or_smaller_size && IsFastElementsKind(kind) &&
!IsFastHoleyElementsKind(kind)) {
kind = GetHoleyElementsKind(kind);
JSObject::TransitionElementsKind(array, kind);
}
// Check whether the backing store should be shrunk.
if (length <= old_capacity) {
if (array->HasFastSmiOrObjectElements()) {
backing_store = JSObject::EnsureWritableFastElements(array);
}
if (2 * length <= old_capacity) {
// If more than half the elements won't be used, trim the array.
if (length == 0) {
array->initialize_elements();
} else {
backing_store->set_length(length);
Address filler_start = backing_store->address() +
BackingStore::OffsetOfElementAt(length);
int filler_size = (old_capacity - length) * ElementSize;
array->GetHeap()->CreateFillerObjectAt(filler_start, filler_size);
}
} else {
// Otherwise, fill the unused tail with holes.
int old_length = FastD2IChecked(array->length()->Number());
for (int i = length; i < old_length; i++) {
Handle<BackingStore>::cast(backing_store)->set_the_hole(i);
}
}
return length_object;
}
// Check whether the backing store should be expanded.
uint32_t min = JSObject::NewElementsCapacity(old_capacity);
uint32_t new_capacity = length > min ? length : min;
if (!array->ShouldConvertToSlowElements(new_capacity)) {
FastElementsAccessorSubclass::
SetFastElementsCapacityAndLength(array, new_capacity, length);
array->ValidateElements();
return length_object;
}
// Request conversion to slow elements.
return isolate->factory()->undefined_value();
}
static Handle<Object> DeleteCommon(Handle<JSObject> obj,
uint32_t key,
JSReceiver::DeleteMode mode) {
ASSERT(obj->HasFastSmiOrObjectElements() ||
obj->HasFastDoubleElements() ||
obj->HasFastArgumentsElements());
Isolate* isolate = obj->GetIsolate();
Heap* heap = obj->GetHeap();
Handle<Object> elements = handle(obj->elements(), isolate);
if (*elements == heap->empty_fixed_array()) {
return isolate->factory()->true_value();
}
Handle<BackingStore> backing_store = Handle<BackingStore>::cast(elements);
bool is_sloppy_arguments_elements_map =
backing_store->map() == heap->sloppy_arguments_elements_map();
if (is_sloppy_arguments_elements_map) {
backing_store = Handle<BackingStore>::cast(
handle(Handle<FixedArray>::cast(backing_store)->get(1), isolate));
}
uint32_t length = static_cast<uint32_t>(
obj->IsJSArray()
? Smi::cast(Handle<JSArray>::cast(obj)->length())->value()
: backing_store->length());
if (key < length) {
if (!is_sloppy_arguments_elements_map) {
ElementsKind kind = KindTraits::Kind;
if (IsFastPackedElementsKind(kind)) {
JSObject::TransitionElementsKind(obj, GetHoleyElementsKind(kind));
}
if (IsFastSmiOrObjectElementsKind(KindTraits::Kind)) {
Handle<Object> writable = JSObject::EnsureWritableFastElements(obj);
backing_store = Handle<BackingStore>::cast(writable);
}
}
backing_store->set_the_hole(key);
// If an old space backing store is larger than a certain size and
// has too few used values, normalize it.
// To avoid doing the check on every delete we require at least
// one adjacent hole to the value being deleted.
const int kMinLengthForSparsenessCheck = 64;
if (backing_store->length() >= kMinLengthForSparsenessCheck &&
!heap->InNewSpace(*backing_store) &&
((key > 0 && backing_store->is_the_hole(key - 1)) ||
(key + 1 < length && backing_store->is_the_hole(key + 1)))) {
int num_used = 0;
for (int i = 0; i < backing_store->length(); ++i) {
if (!backing_store->is_the_hole(i)) ++num_used;
// Bail out early if more than 1/4 is used.
if (4 * num_used > backing_store->length()) break;
}
if (4 * num_used <= backing_store->length()) {
JSObject::NormalizeElements(obj);
}
}
}
return isolate->factory()->true_value();
}
virtual Handle<Object> Delete(
Handle<JSObject> obj,
uint32_t key,
JSReceiver::DeleteMode mode) V8_FINAL V8_OVERRIDE {
return DeleteCommon(obj, key, mode);
}
static bool HasElementImpl(
Object* receiver,
JSObject* holder,
uint32_t key,
FixedArrayBase* backing_store) {
if (key >= static_cast<uint32_t>(backing_store->length())) {
return false;
}
return !BackingStore::cast(backing_store)->is_the_hole(key);
}
static void ValidateContents(JSObject* holder, int length) {
#if DEBUG
FixedArrayBase* elements = holder->elements();
Heap* heap = elements->GetHeap();
Map* map = elements->map();
ASSERT((IsFastSmiOrObjectElementsKind(KindTraits::Kind) &&
(map == heap->fixed_array_map() ||
map == heap->fixed_cow_array_map())) ||
(IsFastDoubleElementsKind(KindTraits::Kind) ==
((map == heap->fixed_array_map() && length == 0) ||
map == heap->fixed_double_array_map())));
for (int i = 0; i < length; i++) {
typename KindTraits::BackingStore* backing_store =
KindTraits::BackingStore::cast(elements);
ASSERT((!IsFastSmiElementsKind(KindTraits::Kind) ||
static_cast<Object*>(backing_store->get(i))->IsSmi()) ||
(IsFastHoleyElementsKind(KindTraits::Kind) ==
backing_store->is_the_hole(i)));
}
#endif
}
};
static inline ElementsKind ElementsKindForArray(FixedArrayBase* array) {
switch (array->map()->instance_type()) {
case FIXED_ARRAY_TYPE:
if (array->IsDictionary()) {
return DICTIONARY_ELEMENTS;
} else {
return FAST_HOLEY_ELEMENTS;
}
case FIXED_DOUBLE_ARRAY_TYPE:
return FAST_HOLEY_DOUBLE_ELEMENTS;
#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) \
case EXTERNAL_##TYPE##_ARRAY_TYPE: \
return EXTERNAL_##TYPE##_ELEMENTS; \
case FIXED_##TYPE##_ARRAY_TYPE: \
return TYPE##_ELEMENTS;
TYPED_ARRAYS(TYPED_ARRAY_CASE)
#undef TYPED_ARRAY_CASE
default:
UNREACHABLE();
}
return FAST_HOLEY_ELEMENTS;
}
template<typename FastElementsAccessorSubclass,
typename KindTraits>
class FastSmiOrObjectElementsAccessor
: public FastElementsAccessor<FastElementsAccessorSubclass,
KindTraits,
kPointerSize> {
public:
explicit FastSmiOrObjectElementsAccessor(const char* name)
: FastElementsAccessor<FastElementsAccessorSubclass,
KindTraits,
kPointerSize>(name) {}
static MaybeObject* CopyElementsImpl(FixedArrayBase* from,
uint32_t from_start,
FixedArrayBase* to,
ElementsKind from_kind,
uint32_t to_start,
int packed_size,
int copy_size) {
ElementsKind to_kind = KindTraits::Kind;
switch (from_kind) {
case FAST_SMI_ELEMENTS:
case FAST_HOLEY_SMI_ELEMENTS:
case FAST_ELEMENTS:
case FAST_HOLEY_ELEMENTS:
CopyObjectToObjectElements(
from, from_kind, from_start, to, to_kind, to_start, copy_size);
return to->GetHeap()->undefined_value();
case FAST_DOUBLE_ELEMENTS:
case FAST_HOLEY_DOUBLE_ELEMENTS:
return CopyDoubleToObjectElements(
from, from_start, to, to_kind, to_start, copy_size);
case DICTIONARY_ELEMENTS:
CopyDictionaryToObjectElements(
from, from_start, to, to_kind, to_start, copy_size);
return to->GetHeap()->undefined_value();
case SLOPPY_ARGUMENTS_ELEMENTS: {
// TODO(verwaest): This is a temporary hack to support extending
// SLOPPY_ARGUMENTS_ELEMENTS in SetFastElementsCapacityAndLength.
// This case should be UNREACHABLE().
FixedArray* parameter_map = FixedArray::cast(from);
FixedArrayBase* arguments = FixedArrayBase::cast(parameter_map->get(1));
ElementsKind from_kind = ElementsKindForArray(arguments);
return CopyElementsImpl(arguments, from_start, to, from_kind,
to_start, packed_size, copy_size);
}
#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) \
case EXTERNAL_##TYPE##_ELEMENTS: \
case TYPE##_ELEMENTS: \
UNREACHABLE();
TYPED_ARRAYS(TYPED_ARRAY_CASE)
#undef TYPED_ARRAY_CASE
}
return NULL;
}
static MaybeObject* SetFastElementsCapacityAndLength(JSObject* obj,
uint32_t capacity,
uint32_t length) {
JSObject::SetFastElementsCapacitySmiMode set_capacity_mode =
obj->HasFastSmiElements()
? JSObject::kAllowSmiElements
: JSObject::kDontAllowSmiElements;
return obj->SetFastElementsCapacityAndLength(capacity,
length,
set_capacity_mode);
}
// TODO(ishell): Temporary wrapper until handlified.
static Handle<Object> SetFastElementsCapacityAndLength(
Handle<JSObject> obj,
int capacity,
int length) {
CALL_HEAP_FUNCTION(obj->GetIsolate(),
SetFastElementsCapacityAndLength(*obj, capacity, length),
Object);
}
};
class FastPackedSmiElementsAccessor
: public FastSmiOrObjectElementsAccessor<
FastPackedSmiElementsAccessor,
ElementsKindTraits<FAST_SMI_ELEMENTS> > {
public:
explicit FastPackedSmiElementsAccessor(const char* name)
: FastSmiOrObjectElementsAccessor<
FastPackedSmiElementsAccessor,
ElementsKindTraits<FAST_SMI_ELEMENTS> >(name) {}
};
class FastHoleySmiElementsAccessor
: public FastSmiOrObjectElementsAccessor<
FastHoleySmiElementsAccessor,
ElementsKindTraits<FAST_HOLEY_SMI_ELEMENTS> > {
public:
explicit FastHoleySmiElementsAccessor(const char* name)
: FastSmiOrObjectElementsAccessor<
FastHoleySmiElementsAccessor,
ElementsKindTraits<FAST_HOLEY_SMI_ELEMENTS> >(name) {}
};
class FastPackedObjectElementsAccessor
: public FastSmiOrObjectElementsAccessor<
FastPackedObjectElementsAccessor,
ElementsKindTraits<FAST_ELEMENTS> > {
public:
explicit FastPackedObjectElementsAccessor(const char* name)
: FastSmiOrObjectElementsAccessor<
FastPackedObjectElementsAccessor,
ElementsKindTraits<FAST_ELEMENTS> >(name) {}
};
class FastHoleyObjectElementsAccessor
: public FastSmiOrObjectElementsAccessor<
FastHoleyObjectElementsAccessor,
ElementsKindTraits<FAST_HOLEY_ELEMENTS> > {
public:
explicit FastHoleyObjectElementsAccessor(const char* name)
: FastSmiOrObjectElementsAccessor<
FastHoleyObjectElementsAccessor,
ElementsKindTraits<FAST_HOLEY_ELEMENTS> >(name) {}
};
template<typename FastElementsAccessorSubclass,
typename KindTraits>
class FastDoubleElementsAccessor
: public FastElementsAccessor<FastElementsAccessorSubclass,
KindTraits,
kDoubleSize> {
public:
explicit FastDoubleElementsAccessor(const char* name)
: FastElementsAccessor<FastElementsAccessorSubclass,
KindTraits,
kDoubleSize>(name) {}
static MaybeObject* SetFastElementsCapacityAndLength(JSObject* obj,
uint32_t capacity,
uint32_t length) {
return obj->SetFastDoubleElementsCapacityAndLength(capacity,
length);
}
// TODO(ishell): Temporary wrapper until handlified.
static Handle<Object> SetFastElementsCapacityAndLength(
Handle<JSObject> obj,
int capacity,
int length) {
CALL_HEAP_FUNCTION(obj->GetIsolate(),
SetFastElementsCapacityAndLength(*obj, capacity, length),
Object);
}
protected:
static MaybeObject* CopyElementsImpl(FixedArrayBase* from,
uint32_t from_start,
FixedArrayBase* to,
ElementsKind from_kind,
uint32_t to_start,
int packed_size,
int copy_size) {
switch (from_kind) {
case FAST_SMI_ELEMENTS:
CopyPackedSmiToDoubleElements(
from, from_start, to, to_start, packed_size, copy_size);
break;
case FAST_HOLEY_SMI_ELEMENTS:
CopySmiToDoubleElements(from, from_start, to, to_start, copy_size);
break;
case FAST_DOUBLE_ELEMENTS:
case FAST_HOLEY_DOUBLE_ELEMENTS:
CopyDoubleToDoubleElements(from, from_start, to, to_start, copy_size);
break;
case FAST_ELEMENTS:
case FAST_HOLEY_ELEMENTS:
CopyObjectToDoubleElements(from, from_start, to, to_start, copy_size);
break;
case DICTIONARY_ELEMENTS:
CopyDictionaryToDoubleElements(
from, from_start, to, to_start, copy_size);
break;
case SLOPPY_ARGUMENTS_ELEMENTS:
UNREACHABLE();
#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) \
case EXTERNAL_##TYPE##_ELEMENTS: \
case TYPE##_ELEMENTS: \
UNREACHABLE();
TYPED_ARRAYS(TYPED_ARRAY_CASE)
#undef TYPED_ARRAY_CASE
}
return to->GetHeap()->undefined_value();
}
};
class FastPackedDoubleElementsAccessor
: public FastDoubleElementsAccessor<
FastPackedDoubleElementsAccessor,
ElementsKindTraits<FAST_DOUBLE_ELEMENTS> > {
public:
friend class ElementsAccessorBase<FastPackedDoubleElementsAccessor,
ElementsKindTraits<FAST_DOUBLE_ELEMENTS> >;
explicit FastPackedDoubleElementsAccessor(const char* name)
: FastDoubleElementsAccessor<
FastPackedDoubleElementsAccessor,
ElementsKindTraits<FAST_DOUBLE_ELEMENTS> >(name) {}
};
class FastHoleyDoubleElementsAccessor
: public FastDoubleElementsAccessor<
FastHoleyDoubleElementsAccessor,
ElementsKindTraits<FAST_HOLEY_DOUBLE_ELEMENTS> > {
public:
friend class ElementsAccessorBase<
FastHoleyDoubleElementsAccessor,
ElementsKindTraits<FAST_HOLEY_DOUBLE_ELEMENTS> >;
explicit FastHoleyDoubleElementsAccessor(const char* name)
: FastDoubleElementsAccessor<
FastHoleyDoubleElementsAccessor,
ElementsKindTraits<FAST_HOLEY_DOUBLE_ELEMENTS> >(name) {}
};
// Super class for all external element arrays.
template<ElementsKind Kind>
class TypedElementsAccessor
: public ElementsAccessorBase<TypedElementsAccessor<Kind>,
ElementsKindTraits<Kind> > {
public:
explicit TypedElementsAccessor(const char* name)
: ElementsAccessorBase<AccessorClass,
ElementsKindTraits<Kind> >(name) {}
protected:
typedef typename ElementsKindTraits<Kind>::BackingStore BackingStore;
typedef TypedElementsAccessor<Kind> AccessorClass;
friend class ElementsAccessorBase<AccessorClass,
ElementsKindTraits<Kind> >;
MUST_USE_RESULT static MaybeObject* GetImpl(Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* backing_store) {
return
key < AccessorClass::GetCapacityImpl(backing_store)
? BackingStore::cast(backing_store)->get(key)
: backing_store->GetHeap()->undefined_value();
}
MUST_USE_RESULT static PropertyAttributes GetAttributesImpl(
Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* backing_store) {
return
key < AccessorClass::GetCapacityImpl(backing_store)
? NONE : ABSENT;
}
MUST_USE_RESULT static PropertyType GetTypeImpl(
Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* backing_store) {
return
key < AccessorClass::GetCapacityImpl(backing_store)
? FIELD : NONEXISTENT;
}
MUST_USE_RESULT static Handle<Object> SetLengthImpl(
Handle<JSObject> obj,
Handle<Object> length,
Handle<FixedArrayBase> backing_store) {
// External arrays do not support changing their length.
UNREACHABLE();
return obj;
}
MUST_USE_RESULT virtual Handle<Object> Delete(
Handle<JSObject> obj,
uint32_t key,
JSReceiver::DeleteMode mode) V8_FINAL V8_OVERRIDE {
// External arrays always ignore deletes.
return obj->GetIsolate()->factory()->true_value();
}
static bool HasElementImpl(Object* receiver,
JSObject* holder,
uint32_t key,
FixedArrayBase* backing_store) {
uint32_t capacity =
AccessorClass::GetCapacityImpl(backing_store);
return key < capacity;
}
};
#define EXTERNAL_ELEMENTS_ACCESSOR(Type, type, TYPE, ctype, size) \
typedef TypedElementsAccessor<EXTERNAL_##TYPE##_ELEMENTS> \
External##Type##ElementsAccessor;
TYPED_ARRAYS(EXTERNAL_ELEMENTS_ACCESSOR)
#undef EXTERNAL_ELEMENTS_ACCESSOR
#define FIXED_ELEMENTS_ACCESSOR(Type, type, TYPE, ctype, size) \
typedef TypedElementsAccessor<TYPE##_ELEMENTS > \
Fixed##Type##ElementsAccessor;
TYPED_ARRAYS(FIXED_ELEMENTS_ACCESSOR)
#undef FIXED_ELEMENTS_ACCESSOR
class DictionaryElementsAccessor
: public ElementsAccessorBase<DictionaryElementsAccessor,
ElementsKindTraits<DICTIONARY_ELEMENTS> > {
public:
explicit DictionaryElementsAccessor(const char* name)
: ElementsAccessorBase<DictionaryElementsAccessor,
ElementsKindTraits<DICTIONARY_ELEMENTS> >(name) {}
// Adjusts the length of the dictionary backing store and returns the new
// length according to ES5 section 15.4.5.2 behavior.
MUST_USE_RESULT static MaybeObject* SetLengthWithoutNormalize(
FixedArrayBase* store,
JSArray* array,
Object* length_object,
uint32_t length) {
SeededNumberDictionary* dict = SeededNumberDictionary::cast(store);
Heap* heap = array->GetHeap();
int capacity = dict->Capacity();
uint32_t new_length = length;
uint32_t old_length = static_cast<uint32_t>(array->length()->Number());
if (new_length < old_length) {
// Find last non-deletable element in range of elements to be
// deleted and adjust range accordingly.
for (int i = 0; i < capacity; i++) {
Object* key = dict->KeyAt(i);
if (key->IsNumber()) {
uint32_t number = static_cast<uint32_t>(key->Number());
if (new_length <= number && number < old_length) {
PropertyDetails details = dict->DetailsAt(i);
if (details.IsDontDelete()) new_length = number + 1;
}
}
}
if (new_length != length) {
MaybeObject* maybe_object = heap->NumberFromUint32(new_length);
if (!maybe_object->To(&length_object)) return maybe_object;
}
}
if (new_length == 0) {
// If the length of a slow array is reset to zero, we clear
// the array and flush backing storage. This has the added
// benefit that the array returns to fast mode.
Object* obj;
MaybeObject* maybe_obj = array->ResetElements();
if (!maybe_obj->ToObject(&obj)) return maybe_obj;
} else {
// Remove elements that should be deleted.
int removed_entries = 0;
Object* the_hole_value = heap->the_hole_value();
for (int i = 0; i < capacity; i++) {
Object* key = dict->KeyAt(i);
if (key->IsNumber()) {
uint32_t number = static_cast<uint32_t>(key->Number());
if (new_length <= number && number < old_length) {
dict->SetEntry(i, the_hole_value, the_hole_value);
removed_entries++;
}
}
}
// Update the number of elements.
dict->ElementsRemoved(removed_entries);
}
return length_object;
}
// TODO(ishell): Temporary wrapper until handlified.
MUST_USE_RESULT static Handle<Object> SetLengthWithoutNormalize(
Handle<FixedArrayBase> store,
Handle<JSArray> array,
Handle<Object> length_object,
uint32_t length) {
CALL_HEAP_FUNCTION(array->GetIsolate(),
SetLengthWithoutNormalize(
*store, *array, *length_object, length),
Object);
}
MUST_USE_RESULT static MaybeObject* DeleteCommon(
JSObject* obj,
uint32_t key,
JSReceiver::DeleteMode mode) {
Isolate* isolate = obj->GetIsolate();
Heap* heap = isolate->heap();
FixedArray* backing_store = FixedArray::cast(obj->elements());
bool is_arguments =
(obj->GetElementsKind() == SLOPPY_ARGUMENTS_ELEMENTS);
if (is_arguments) {
backing_store = FixedArray::cast(backing_store->get(1));
}
SeededNumberDictionary* dictionary =
SeededNumberDictionary::cast(backing_store);
int entry = dictionary->FindEntry(key);
if (entry != SeededNumberDictionary::kNotFound) {
Object* result = dictionary->DeleteProperty(entry, mode);
if (result == heap->false_value()) {
if (mode == JSObject::STRICT_DELETION) {
// Deleting a non-configurable property in strict mode.
HandleScope scope(isolate);
Handle<Object> holder(obj, isolate);
Handle<Object> name = isolate->factory()->NewNumberFromUint(key);
Handle<Object> args[2] = { name, holder };
Handle<Object> error =
isolate->factory()->NewTypeError("strict_delete_property",
HandleVector(args, 2));
return isolate->Throw(*error);
}
return heap->false_value();
}
MaybeObject* maybe_elements = dictionary->Shrink(key);
FixedArray* new_elements = NULL;
if (!maybe_elements->To(&new_elements)) {
return maybe_elements;
}
if (is_arguments) {
FixedArray::cast(obj->elements())->set(1, new_elements);
} else {
obj->set_elements(new_elements);
}
}
return heap->true_value();
}
// TODO(ishell): Temporary wrapper until handlified.
MUST_USE_RESULT static Handle<Object> DeleteCommon(
Handle<JSObject> obj,
uint32_t key,
JSReceiver::DeleteMode mode) {
CALL_HEAP_FUNCTION(obj->GetIsolate(),
DeleteCommon(*obj, key, mode),
Object);
}
MUST_USE_RESULT static MaybeObject* CopyElementsImpl(FixedArrayBase* from,
uint32_t from_start,
FixedArrayBase* to,
ElementsKind from_kind,
uint32_t to_start,
int packed_size,
int copy_size) {
UNREACHABLE();
return NULL;
}
protected:
friend class ElementsAccessorBase<DictionaryElementsAccessor,
ElementsKindTraits<DICTIONARY_ELEMENTS> >;
MUST_USE_RESULT virtual Handle<Object> Delete(
Handle<JSObject> obj,
uint32_t key,
JSReceiver::DeleteMode mode) V8_FINAL V8_OVERRIDE {
return DeleteCommon(obj, key, mode);
}
MUST_USE_RESULT static MaybeObject* GetImpl(
Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* store) {
SeededNumberDictionary* backing_store = SeededNumberDictionary::cast(store);
int entry = backing_store->FindEntry(key);
if (entry != SeededNumberDictionary::kNotFound) {
Object* element = backing_store->ValueAt(entry);
PropertyDetails details = backing_store->DetailsAt(entry);
if (details.type() == CALLBACKS) {
return obj->GetElementWithCallback(receiver,
element,
key,
obj);
} else {
return element;
}
}
return obj->GetHeap()->the_hole_value();
}
MUST_USE_RESULT static PropertyAttributes GetAttributesImpl(
Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* backing_store) {
SeededNumberDictionary* dictionary =
SeededNumberDictionary::cast(backing_store);
int entry = dictionary->FindEntry(key);
if (entry != SeededNumberDictionary::kNotFound) {
return dictionary->DetailsAt(entry).attributes();
}
return ABSENT;
}
MUST_USE_RESULT static PropertyType GetTypeImpl(
Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* store) {
SeededNumberDictionary* backing_store = SeededNumberDictionary::cast(store);
int entry = backing_store->FindEntry(key);
if (entry != SeededNumberDictionary::kNotFound) {
return backing_store->DetailsAt(entry).type();
}
return NONEXISTENT;
}
MUST_USE_RESULT static AccessorPair* GetAccessorPairImpl(
Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* store) {
SeededNumberDictionary* backing_store = SeededNumberDictionary::cast(store);
int entry = backing_store->FindEntry(key);
if (entry != SeededNumberDictionary::kNotFound &&
backing_store->DetailsAt(entry).type() == CALLBACKS &&
backing_store->ValueAt(entry)->IsAccessorPair()) {
return AccessorPair::cast(backing_store->ValueAt(entry));
}
return NULL;
}
static bool HasElementImpl(Object* receiver,
JSObject* holder,
uint32_t key,
FixedArrayBase* backing_store) {
return SeededNumberDictionary::cast(backing_store)->FindEntry(key) !=
SeededNumberDictionary::kNotFound;
}
static uint32_t GetKeyForIndexImpl(FixedArrayBase* store,
uint32_t index) {
SeededNumberDictionary* dict = SeededNumberDictionary::cast(store);
Object* key = dict->KeyAt(index);
return Smi::cast(key)->value();
}
};
class SloppyArgumentsElementsAccessor : public ElementsAccessorBase<
SloppyArgumentsElementsAccessor,
ElementsKindTraits<SLOPPY_ARGUMENTS_ELEMENTS> > {
public:
explicit SloppyArgumentsElementsAccessor(const char* name)
: ElementsAccessorBase<
SloppyArgumentsElementsAccessor,
ElementsKindTraits<SLOPPY_ARGUMENTS_ELEMENTS> >(name) {}
protected:
friend class ElementsAccessorBase<
SloppyArgumentsElementsAccessor,
ElementsKindTraits<SLOPPY_ARGUMENTS_ELEMENTS> >;
MUST_USE_RESULT static MaybeObject* GetImpl(Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* parameters) {
FixedArray* parameter_map = FixedArray::cast(parameters);
Object* probe = GetParameterMapArg(obj, parameter_map, key);
if (!probe->IsTheHole()) {
Context* context = Context::cast(parameter_map->get(0));
int context_index = Smi::cast(probe)->value();
ASSERT(!context->get(context_index)->IsTheHole());
return context->get(context_index);
} else {
// Object is not mapped, defer to the arguments.
FixedArray* arguments = FixedArray::cast(parameter_map->get(1));
MaybeObject* maybe_result = ElementsAccessor::ForArray(arguments)->Get(
receiver, obj, key, arguments);
Object* result;
if (!maybe_result->ToObject(&result)) return maybe_result;
// Elements of the arguments object in slow mode might be slow aliases.
if (result->IsAliasedArgumentsEntry()) {
AliasedArgumentsEntry* entry = AliasedArgumentsEntry::cast(result);
Context* context = Context::cast(parameter_map->get(0));
int context_index = entry->aliased_context_slot();
ASSERT(!context->get(context_index)->IsTheHole());
return context->get(context_index);
} else {
return result;
}
}
}
MUST_USE_RESULT static PropertyAttributes GetAttributesImpl(
Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* backing_store) {
FixedArray* parameter_map = FixedArray::cast(backing_store);
Object* probe = GetParameterMapArg(obj, parameter_map, key);
if (!probe->IsTheHole()) {
return NONE;
} else {
// If not aliased, check the arguments.
FixedArray* arguments = FixedArray::cast(parameter_map->get(1));
return ElementsAccessor::ForArray(arguments)->GetAttributes(
receiver, obj, key, arguments);
}
}
MUST_USE_RESULT static PropertyType GetTypeImpl(
Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* parameters) {
FixedArray* parameter_map = FixedArray::cast(parameters);
Object* probe = GetParameterMapArg(obj, parameter_map, key);
if (!probe->IsTheHole()) {
return FIELD;
} else {
// If not aliased, check the arguments.
FixedArray* arguments = FixedArray::cast(parameter_map->get(1));
return ElementsAccessor::ForArray(arguments)->GetType(
receiver, obj, key, arguments);
}
}
MUST_USE_RESULT static AccessorPair* GetAccessorPairImpl(
Object* receiver,
JSObject* obj,
uint32_t key,
FixedArrayBase* parameters) {
FixedArray* parameter_map = FixedArray::cast(parameters);
Object* probe = GetParameterMapArg(obj, parameter_map, key);
if (!probe->IsTheHole()) {
return NULL;
} else {
// If not aliased, check the arguments.
FixedArray* arguments = FixedArray::cast(parameter_map->get(1));
return ElementsAccessor::ForArray(arguments)->GetAccessorPair(
receiver, obj, key, arguments);
}
}
MUST_USE_RESULT static Handle<Object> SetLengthImpl(
Handle<JSObject> obj,
Handle<Object> length,
Handle<FixedArrayBase> parameter_map) {
// TODO(mstarzinger): This was never implemented but will be used once we
// correctly implement [[DefineOwnProperty]] on arrays.
UNIMPLEMENTED();
return obj;
}
MUST_USE_RESULT virtual Handle<Object> Delete(
Handle<JSObject> obj,
uint32_t key,
JSReceiver::DeleteMode mode) V8_FINAL V8_OVERRIDE {
Isolate* isolate = obj->GetIsolate();
Handle<FixedArray> parameter_map =
handle(FixedArray::cast(obj->elements()), isolate);
Handle<Object> probe = GetParameterMapArg(obj, parameter_map, key);
if (!probe->IsTheHole()) {
// TODO(kmillikin): We could check if this was the last aliased
// parameter, and revert to normal elements in that case. That
// would enable GC of the context.
parameter_map->set_the_hole(key + 2);
} else {
Handle<FixedArray> arguments =
handle(FixedArray::cast(parameter_map->get(1)), isolate);
if (arguments->IsDictionary()) {
return DictionaryElementsAccessor::DeleteCommon(obj, key, mode);
} else {
// It's difficult to access the version of DeleteCommon that is declared
// in the templatized super class, call the concrete implementation in
// the class for the most generalized ElementsKind subclass.
return FastHoleyObjectElementsAccessor::DeleteCommon(obj, key, mode);
}
}
return isolate->factory()->true_value();
}
MUST_USE_RESULT static MaybeObject* CopyElementsImpl(FixedArrayBase* from,
uint32_t from_start,
FixedArrayBase* to,
ElementsKind from_kind,
uint32_t to_start,
int packed_size,
int copy_size) {
UNREACHABLE();
return NULL;
}
static uint32_t GetCapacityImpl(FixedArrayBase* backing_store) {
FixedArray* parameter_map = FixedArray::cast(backing_store);
FixedArrayBase* arguments = FixedArrayBase::cast(parameter_map->get(1));
return Max(static_cast<uint32_t>(parameter_map->length() - 2),
ForArray(arguments)->GetCapacity(arguments));
}
static uint32_t GetKeyForIndexImpl(FixedArrayBase* dict,
uint32_t index) {
return index;
}
static bool HasElementImpl(Object* receiver,
JSObject* holder,
uint32_t key,
FixedArrayBase* parameters) {
FixedArray* parameter_map = FixedArray::cast(parameters);
Object* probe = GetParameterMapArg(holder, parameter_map, key);
if (!probe->IsTheHole()) {
return true;
} else {
FixedArrayBase* arguments =
FixedArrayBase::cast(FixedArray::cast(parameter_map)->get(1));
ElementsAccessor* accessor = ElementsAccessor::ForArray(arguments);
return !accessor->Get(receiver, holder, key, arguments)->IsTheHole();
}
}
private:
// TODO(ishell): remove when all usages are handlified.
static Object* GetParameterMapArg(JSObject* holder,
FixedArray* parameter_map,
uint32_t key) {
uint32_t length = holder->IsJSArray()
? Smi::cast(JSArray::cast(holder)->length())->value()
: parameter_map->length();
return key < (length - 2)
? parameter_map->get(key + 2)
: parameter_map->GetHeap()->the_hole_value();
}
static Handle<Object> GetParameterMapArg(Handle<JSObject> holder,
Handle<FixedArray> parameter_map,
uint32_t key) {
Isolate* isolate = holder->GetIsolate();
uint32_t length = holder->IsJSArray()
? Smi::cast(Handle<JSArray>::cast(holder)->length())->value()
: parameter_map->length();
return key < (length - 2)
? handle(parameter_map->get(key + 2), isolate)
: Handle<Object>::cast(isolate->factory()->the_hole_value());
}
};
ElementsAccessor* ElementsAccessor::ForArray(FixedArrayBase* array) {
return elements_accessors_[ElementsKindForArray(array)];
}
void ElementsAccessor::InitializeOncePerProcess() {
static ElementsAccessor* accessor_array[] = {
#define ACCESSOR_ARRAY(Class, Kind, Store) new Class(#Kind),
ELEMENTS_LIST(ACCESSOR_ARRAY)
#undef ACCESSOR_ARRAY
};
STATIC_ASSERT((sizeof(accessor_array) / sizeof(*accessor_array)) ==
kElementsKindCount);
elements_accessors_ = accessor_array;
}
void ElementsAccessor::TearDown() {
#define ACCESSOR_DELETE(Class, Kind, Store) delete elements_accessors_[Kind];
ELEMENTS_LIST(ACCESSOR_DELETE)
#undef ACCESSOR_DELETE
elements_accessors_ = NULL;
}
template <typename ElementsAccessorSubclass, typename ElementsKindTraits>
MUST_USE_RESULT Handle<Object> ElementsAccessorBase<ElementsAccessorSubclass,
ElementsKindTraits>::
SetLengthImpl(Handle<JSObject> obj,
Handle<Object> length,
Handle<FixedArrayBase> backing_store) {
Isolate* isolate = obj->GetIsolate();
Handle<JSArray> array = Handle<JSArray>::cast(obj);
// Fast case: The new length fits into a Smi.
Handle<Object> smi_length = Object::ToSmi(isolate, length);
if (!smi_length.is_null() && smi_length->IsSmi()) {
const int value = Handle<Smi>::cast(smi_length)->value();
if (value >= 0) {
Handle<Object> new_length = ElementsAccessorSubclass::
SetLengthWithoutNormalize(backing_store, array, smi_length, value);
RETURN_IF_EMPTY_HANDLE_VALUE(isolate, new_length, new_length);
// even though the proposed length was a smi, new_length could
// still be a heap number because SetLengthWithoutNormalize doesn't
// allow the array length property to drop below the index of
// non-deletable elements.
ASSERT(new_length->IsSmi() || new_length->IsHeapNumber() ||
new_length->IsUndefined());
if (new_length->IsSmi()) {
array->set_length(*Handle<Smi>::cast(new_length));
return array;
} else if (new_length->IsHeapNumber()) {
array->set_length(*new_length);
return array;
}
} else {
return ThrowArrayLengthRangeError(isolate);
}
}
// Slow case: The new length does not fit into a Smi or conversion
// to slow elements is needed for other reasons.
if (length->IsNumber()) {
uint32_t value;
if (length->ToArrayIndex(&value)) {
Handle<SeededNumberDictionary> dictionary =
JSObject::NormalizeElements(array);
RETURN_IF_EMPTY_HANDLE_VALUE(isolate, dictionary, dictionary);
Handle<Object> new_length = DictionaryElementsAccessor::
SetLengthWithoutNormalize(dictionary, array, length, value);
RETURN_IF_EMPTY_HANDLE_VALUE(isolate, new_length, new_length);
ASSERT(new_length->IsNumber());
array->set_length(*new_length);
return array;
} else {
return ThrowArrayLengthRangeError(isolate);
}
}
// Fall-back case: The new length is not a number so make the array
// size one and set only element to length.
Handle<FixedArray> new_backing_store = isolate->factory()->NewFixedArray(1);
new_backing_store->set(0, *length);
JSArray::SetContent(array, new_backing_store);
return array;
}
Handle<Object> ArrayConstructInitializeElements(Handle<JSArray> array,
Arguments* args) {
// Optimize the case where there is one argument and the argument is a
// small smi.
if (args->length() == 1) {
Handle<Object> obj = args->at<Object>(0);
if (obj->IsSmi()) {
int len = Handle<Smi>::cast(obj)->value();
if (len > 0 && len < JSObject::kInitialMaxFastElementArray) {
ElementsKind elements_kind = array->GetElementsKind();
JSArray::Initialize(array, len, len);
if (!IsFastHoleyElementsKind(elements_kind)) {
elements_kind = GetHoleyElementsKind(elements_kind);
JSObject::TransitionElementsKind(array, elements_kind);
}
return array;
} else if (len == 0) {
JSArray::Initialize(array, JSArray::kPreallocatedArrayElements);
return array;
}
}
// Take the argument as the length.
JSArray::Initialize(array, 0);
return JSArray::SetElementsLength(array, obj);
}
// Optimize the case where there are no parameters passed.
if (args->length() == 0) {
JSArray::Initialize(array, JSArray::kPreallocatedArrayElements);
return array;
}
Factory* factory = array->GetIsolate()->factory();
// Set length and elements on the array.
int number_of_elements = args->length();
JSObject::EnsureCanContainElements(
array, args, 0, number_of_elements, ALLOW_CONVERTED_DOUBLE_ELEMENTS);
// Allocate an appropriately typed elements array.
ElementsKind elements_kind = array->GetElementsKind();
Handle<FixedArrayBase> elms;
if (IsFastDoubleElementsKind(elements_kind)) {
elms = Handle<FixedArrayBase>::cast(
factory->NewFixedDoubleArray(number_of_elements));
} else {
elms = Handle<FixedArrayBase>::cast(
factory->NewFixedArrayWithHoles(number_of_elements));
}
// Fill in the content
switch (array->GetElementsKind()) {
case FAST_HOLEY_SMI_ELEMENTS:
case FAST_SMI_ELEMENTS: {
Handle<FixedArray> smi_elms = Handle<FixedArray>::cast(elms);
for (int index = 0; index < number_of_elements; index++) {
smi_elms->set(index, (*args)[index], SKIP_WRITE_BARRIER);
}
break;
}
case FAST_HOLEY_ELEMENTS:
case FAST_ELEMENTS: {
DisallowHeapAllocation no_gc;
WriteBarrierMode mode = elms->GetWriteBarrierMode(no_gc);
Handle<FixedArray> object_elms = Handle<FixedArray>::cast(elms);
for (int index = 0; index < number_of_elements; index++) {
object_elms->set(index, (*args)[index], mode);
}
break;
}
case FAST_HOLEY_DOUBLE_ELEMENTS:
case FAST_DOUBLE_ELEMENTS: {
Handle<FixedDoubleArray> double_elms =
Handle<FixedDoubleArray>::cast(elms);
for (int index = 0; index < number_of_elements; index++) {
double_elms->set(index, (*args)[index]->Number());
}
break;
}
default:
UNREACHABLE();
break;
}
array->set_elements(*elms);
array->set_length(Smi::FromInt(number_of_elements));
return array;
}
} } // namespace v8::internal
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