src/v8/src/objects/fixed-array-inl.h

// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_OBJECTS_FIXED_ARRAY_INL_H_
#define V8_OBJECTS_FIXED_ARRAY_INL_H_

#include "src/objects.h"

// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"

namespace v8 {
namespace internal {

TYPE_CHECKER(ByteArray, BYTE_ARRAY_TYPE)
TYPE_CHECKER(FixedArrayExact, FIXED_ARRAY_TYPE)
TYPE_CHECKER(FixedDoubleArray, FIXED_DOUBLE_ARRAY_TYPE)
TYPE_CHECKER(WeakFixedArray, FIXED_ARRAY_TYPE)

CAST_ACCESSOR(ArrayList)
CAST_ACCESSOR(ByteArray)
CAST_ACCESSOR(FixedArray)
CAST_ACCESSOR(FixedArrayBase)
CAST_ACCESSOR(FixedDoubleArray)
CAST_ACCESSOR(FixedTypedArrayBase)
CAST_ACCESSOR(TemplateList)
CAST_ACCESSOR(WeakFixedArray)

SMI_ACCESSORS(FixedArrayBase, length, kLengthOffset)
SYNCHRONIZED_SMI_ACCESSORS(FixedArrayBase, length, kLengthOffset)

Object* FixedArrayBase::unchecked_synchronized_length() const {
  return ACQUIRE_READ_FIELD(this, kLengthOffset);
}

ACCESSORS(FixedTypedArrayBase, base_pointer, Object, kBasePointerOffset)

Object** FixedArray::GetFirstElementAddress() {
  return reinterpret_cast<Object**>(FIELD_ADDR(this, OffsetOfElementAt(0)));
}

bool FixedArray::ContainsOnlySmisOrHoles() {
  Object* the_hole = GetHeap()->the_hole_value();
  Object** current = GetFirstElementAddress();
  for (int i = 0; i < length(); ++i) {
    Object* candidate = *current++;
    if (!candidate->IsSmi() && candidate != the_hole) return false;
  }
  return true;
}

Object* FixedArray::get(int index) const {
  SLOW_DCHECK(index >= 0 && index < this->length());
  return RELAXED_READ_FIELD(this, kHeaderSize + index * kPointerSize);
}

Handle<Object> FixedArray::get(FixedArray* array, int index, Isolate* isolate) {
  return handle(array->get(index), isolate);
}

template <class T>
MaybeHandle<T> FixedArray::GetValue(Isolate* isolate, int index) const {
  Object* obj = get(index);
  if (obj->IsUndefined(isolate)) return MaybeHandle<T>();
  return Handle<T>(T::cast(obj), isolate);
}

template <class T>
Handle<T> FixedArray::GetValueChecked(Isolate* isolate, int index) const {
  Object* obj = get(index);
  CHECK(!obj->IsUndefined(isolate));
  return Handle<T>(T::cast(obj), isolate);
}

bool FixedArray::is_the_hole(Isolate* isolate, int index) {
  return get(index)->IsTheHole(isolate);
}

void FixedArray::set(int index, Smi* value) {
  DCHECK_NE(map(), GetHeap()->fixed_cow_array_map());
  DCHECK_LT(index, this->length());
  DCHECK(reinterpret_cast<Object*>(value)->IsSmi());
  int offset = kHeaderSize + index * kPointerSize;
  RELAXED_WRITE_FIELD(this, offset, value);
}

void FixedArray::set(int index, Object* value) {
  DCHECK_NE(GetHeap()->fixed_cow_array_map(), map());
  DCHECK(IsFixedArray());
  DCHECK_GE(index, 0);
  DCHECK_LT(index, this->length());
  int offset = kHeaderSize + index * kPointerSize;
  RELAXED_WRITE_FIELD(this, offset, value);
  WRITE_BARRIER(GetHeap(), this, offset, value);
}

void FixedArray::set(int index, Object* value, WriteBarrierMode mode) {
  DCHECK_NE(map(), GetHeap()->fixed_cow_array_map());
  DCHECK_GE(index, 0);
  DCHECK_LT(index, this->length());
  int offset = kHeaderSize + index * kPointerSize;
  RELAXED_WRITE_FIELD(this, offset, value);
  CONDITIONAL_WRITE_BARRIER(GetHeap(), this, offset, value, mode);
}

void FixedArray::NoWriteBarrierSet(FixedArray* array, int index,
                                   Object* value) {
  DCHECK_NE(array->map(), array->GetHeap()->fixed_cow_array_map());
  DCHECK_GE(index, 0);
  DCHECK_LT(index, array->length());
  DCHECK(!array->GetHeap()->InNewSpace(value));
  RELAXED_WRITE_FIELD(array, kHeaderSize + index * kPointerSize, value);
}

void FixedArray::set_undefined(int index) {
  set_undefined(GetIsolate(), index);
}

void FixedArray::set_undefined(Isolate* isolate, int index) {
  FixedArray::NoWriteBarrierSet(this, index,
                                isolate->heap()->undefined_value());
}

void FixedArray::set_null(int index) { set_null(GetIsolate(), index); }

void FixedArray::set_null(Isolate* isolate, int index) {
  FixedArray::NoWriteBarrierSet(this, index, isolate->heap()->null_value());
}

void FixedArray::set_the_hole(int index) { set_the_hole(GetIsolate(), index); }

void FixedArray::set_the_hole(Isolate* isolate, int index) {
  FixedArray::NoWriteBarrierSet(this, index, isolate->heap()->the_hole_value());
}

void FixedArray::FillWithHoles(int from, int to) {
  Isolate* isolate = GetIsolate();
  for (int i = from; i < to; i++) {
    set_the_hole(isolate, i);
  }
}

Object** FixedArray::data_start() {
  return HeapObject::RawField(this, kHeaderSize);
}

Object** FixedArray::RawFieldOfElementAt(int index) {
  return HeapObject::RawField(this, OffsetOfElementAt(index));
}

double FixedDoubleArray::get_scalar(int index) {
  DCHECK(map() != GetHeap()->fixed_cow_array_map() &&
         map() != GetHeap()->fixed_array_map());
  DCHECK(index >= 0 && index < this->length());
  DCHECK(!is_the_hole(index));
  return READ_DOUBLE_FIELD(this, kHeaderSize + index * kDoubleSize);
}

uint64_t FixedDoubleArray::get_representation(int index) {
  DCHECK(map() != GetHeap()->fixed_cow_array_map() &&
         map() != GetHeap()->fixed_array_map());
  DCHECK(index >= 0 && index < this->length());
  int offset = kHeaderSize + index * kDoubleSize;
  return READ_UINT64_FIELD(this, offset);
}

Handle<Object> FixedDoubleArray::get(FixedDoubleArray* array, int index,
                                     Isolate* isolate) {
  if (array->is_the_hole(index)) {
    return isolate->factory()->the_hole_value();
  } else {
    return isolate->factory()->NewNumber(array->get_scalar(index));
  }
}

void FixedDoubleArray::set(int index, double value) {
  DCHECK(map() != GetHeap()->fixed_cow_array_map() &&
         map() != GetHeap()->fixed_array_map());
  int offset = kHeaderSize + index * kDoubleSize;
  if (std::isnan(value)) {
    WRITE_DOUBLE_FIELD(this, offset, std::numeric_limits<double>::quiet_NaN());
  } else {
    WRITE_DOUBLE_FIELD(this, offset, value);
  }
  DCHECK(!is_the_hole(index));
}

void FixedDoubleArray::set_the_hole(Isolate* isolate, int index) {
  set_the_hole(index);
}

void FixedDoubleArray::set_the_hole(int index) {
  DCHECK(map() != GetHeap()->fixed_cow_array_map() &&
         map() != GetHeap()->fixed_array_map());
  int offset = kHeaderSize + index * kDoubleSize;
  WRITE_UINT64_FIELD(this, offset, kHoleNanInt64);
}

bool FixedDoubleArray::is_the_hole(Isolate* isolate, int index) {
  return is_the_hole(index);
}

bool FixedDoubleArray::is_the_hole(int index) {
  return get_representation(index) == kHoleNanInt64;
}

double* FixedDoubleArray::data_start() {
  return reinterpret_cast<double*>(FIELD_ADDR(this, kHeaderSize));
}

void FixedDoubleArray::FillWithHoles(int from, int to) {
  for (int i = from; i < to; i++) {
    set_the_hole(i);
  }
}

Object* WeakFixedArray::Get(int index) const {
  Object* raw = FixedArray::cast(this)->get(index + kFirstIndex);
  if (raw->IsSmi()) return raw;
  DCHECK(raw->IsWeakCell());
  return WeakCell::cast(raw)->value();
}

bool WeakFixedArray::IsEmptySlot(int index) const {
  DCHECK(index < Length());
  return Get(index)->IsSmi();
}

void WeakFixedArray::Clear(int index) {
  FixedArray::cast(this)->set(index + kFirstIndex, Smi::kZero);
}

int WeakFixedArray::Length() const {
  return FixedArray::cast(this)->length() - kFirstIndex;
}

int WeakFixedArray::last_used_index() const {
  return Smi::ToInt(FixedArray::cast(this)->get(kLastUsedIndexIndex));
}

void WeakFixedArray::set_last_used_index(int index) {
  FixedArray::cast(this)->set(kLastUsedIndexIndex, Smi::FromInt(index));
}

template <class T>
T* WeakFixedArray::Iterator::Next() {
  if (list_ != nullptr) {
    // Assert that list did not change during iteration.
    DCHECK_EQ(last_used_index_, list_->last_used_index());
    while (index_ < list_->Length()) {
      Object* item = list_->Get(index_++);
      if (item != Empty()) return T::cast(item);
    }
    list_ = nullptr;
  }
  return nullptr;
}

int ArrayList::Length() const {
  if (FixedArray::cast(this)->length() == 0) return 0;
  return Smi::ToInt(FixedArray::cast(this)->get(kLengthIndex));
}

void ArrayList::SetLength(int length) {
  return FixedArray::cast(this)->set(kLengthIndex, Smi::FromInt(length));
}

Object* ArrayList::Get(int index) const {
  return FixedArray::cast(this)->get(kFirstIndex + index);
}

Object** ArrayList::Slot(int index) {
  return data_start() + kFirstIndex + index;
}

void ArrayList::Set(int index, Object* obj, WriteBarrierMode mode) {
  FixedArray::cast(this)->set(kFirstIndex + index, obj, mode);
}

void ArrayList::Clear(int index, Object* undefined) {
  DCHECK(undefined->IsUndefined(GetIsolate()));
  FixedArray::cast(this)->set(kFirstIndex + index, undefined,
                              SKIP_WRITE_BARRIER);
}

int ByteArray::Size() { return RoundUp(length() + kHeaderSize, kPointerSize); }

byte ByteArray::get(int index) const {
  DCHECK(index >= 0 && index < this->length());
  return READ_BYTE_FIELD(this, kHeaderSize + index * kCharSize);
}

void ByteArray::set(int index, byte value) {
  DCHECK(index >= 0 && index < this->length());
  WRITE_BYTE_FIELD(this, kHeaderSize + index * kCharSize, value);
}

void ByteArray::copy_in(int index, const byte* buffer, int length) {
  DCHECK(index >= 0 && length >= 0 && length <= kMaxInt - index &&
         index + length <= this->length());
  byte* dst_addr = FIELD_ADDR(this, kHeaderSize + index * kCharSize);
  memcpy(dst_addr, buffer, length);
}

void ByteArray::copy_out(int index, byte* buffer, int length) {
  DCHECK(index >= 0 && length >= 0 && length <= kMaxInt - index &&
         index + length <= this->length());
  const byte* src_addr = FIELD_ADDR(this, kHeaderSize + index * kCharSize);
  memcpy(buffer, src_addr, length);
}

int ByteArray::get_int(int index) const {
  DCHECK(index >= 0 && index < this->length() / kIntSize);
  return READ_INT_FIELD(this, kHeaderSize + index * kIntSize);
}

void ByteArray::set_int(int index, int value) {
  DCHECK(index >= 0 && index < this->length() / kIntSize);
  WRITE_INT_FIELD(this, kHeaderSize + index * kIntSize, value);
}

uint32_t ByteArray::get_uint32(int index) const {
  DCHECK(index >= 0 && index < this->length() / kUInt32Size);
  return READ_UINT32_FIELD(this, kHeaderSize + index * kUInt32Size);
}

void ByteArray::set_uint32(int index, uint32_t value) {
  DCHECK(index >= 0 && index < this->length() / kUInt32Size);
  WRITE_UINT32_FIELD(this, kHeaderSize + index * kUInt32Size, value);
}

void ByteArray::clear_padding() {
  int data_size = length() + kHeaderSize;
  memset(address() + data_size, 0, Size() - data_size);
}

ByteArray* ByteArray::FromDataStartAddress(Address address) {
  DCHECK_TAG_ALIGNED(address);
  return reinterpret_cast<ByteArray*>(address - kHeaderSize + kHeapObjectTag);
}

int ByteArray::DataSize() const { return RoundUp(length(), kPointerSize); }

int ByteArray::ByteArraySize() { return SizeFor(this->length()); }

Address ByteArray::GetDataStartAddress() {
  return reinterpret_cast<Address>(this) - kHeapObjectTag + kHeaderSize;
}

template <class T>
PodArray<T>* PodArray<T>::cast(Object* object) {
  SLOW_DCHECK(object->IsByteArray());
  return reinterpret_cast<PodArray<T>*>(object);
}
template <class T>
const PodArray<T>* PodArray<T>::cast(const Object* object) {
  SLOW_DCHECK(object->IsByteArray());
  return reinterpret_cast<const PodArray<T>*>(object);
}

// static
template <class T>
Handle<PodArray<T>> PodArray<T>::New(Isolate* isolate, int length,
                                     PretenureFlag pretenure) {
  return Handle<PodArray<T>>::cast(
      isolate->factory()->NewByteArray(length * sizeof(T), pretenure));
}

void* FixedTypedArrayBase::external_pointer() const {
  intptr_t ptr = READ_INTPTR_FIELD(this, kExternalPointerOffset);
  return reinterpret_cast<void*>(ptr);
}

void FixedTypedArrayBase::set_external_pointer(void* value,
                                               WriteBarrierMode mode) {
  intptr_t ptr = reinterpret_cast<intptr_t>(value);
  WRITE_INTPTR_FIELD(this, kExternalPointerOffset, ptr);
}

void* FixedTypedArrayBase::DataPtr() {
  return reinterpret_cast<void*>(
      reinterpret_cast<intptr_t>(base_pointer()) +
      reinterpret_cast<intptr_t>(external_pointer()));
}

int FixedTypedArrayBase::ElementSize(InstanceType type) {
  int element_size;
  switch (type) {
#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) \
  case FIXED_##TYPE##_ARRAY_TYPE:                       \
    element_size = size;                                \
    break;

    TYPED_ARRAYS(TYPED_ARRAY_CASE)
#undef TYPED_ARRAY_CASE
    default:
      UNREACHABLE();
  }
  return element_size;
}

int FixedTypedArrayBase::DataSize(InstanceType type) const {
  if (base_pointer() == Smi::kZero) return 0;
  return length() * ElementSize(type);
}

int FixedTypedArrayBase::DataSize() const {
  return DataSize(map()->instance_type());
}

size_t FixedTypedArrayBase::ByteLength() const {
  return static_cast<size_t>(length()) *
         static_cast<size_t>(ElementSize(map()->instance_type()));
}

int FixedTypedArrayBase::size() const {
  return OBJECT_POINTER_ALIGN(kDataOffset + DataSize());
}

int FixedTypedArrayBase::TypedArraySize(InstanceType type) const {
  return OBJECT_POINTER_ALIGN(kDataOffset + DataSize(type));
}

// static
int FixedTypedArrayBase::TypedArraySize(InstanceType type, int length) {
  return OBJECT_POINTER_ALIGN(kDataOffset + length * ElementSize(type));
}

uint8_t Uint8ArrayTraits::defaultValue() { return 0; }

uint8_t Uint8ClampedArrayTraits::defaultValue() { return 0; }

int8_t Int8ArrayTraits::defaultValue() { return 0; }

uint16_t Uint16ArrayTraits::defaultValue() { return 0; }

int16_t Int16ArrayTraits::defaultValue() { return 0; }

uint32_t Uint32ArrayTraits::defaultValue() { return 0; }

int32_t Int32ArrayTraits::defaultValue() { return 0; }

float Float32ArrayTraits::defaultValue() {
  return std::numeric_limits<float>::quiet_NaN();
}

double Float64ArrayTraits::defaultValue() {
  return std::numeric_limits<double>::quiet_NaN();
}

template <class Traits>
typename Traits::ElementType FixedTypedArray<Traits>::get_scalar(int index) {
  DCHECK((index >= 0) && (index < this->length()));
  return FixedTypedArray<Traits>::get_scalar_from_data_ptr(DataPtr(), index);
}

// static
template <class Traits>
typename Traits::ElementType FixedTypedArray<Traits>::get_scalar_from_data_ptr(
    void* data_ptr, int index) {
  typename Traits::ElementType* ptr = reinterpret_cast<ElementType*>(data_ptr);
  // The JavaScript memory model allows for racy reads and writes to a
  // SharedArrayBuffer's backing store, which will always be a FixedTypedArray.
  // ThreadSanitizer will catch these racy accesses and warn about them, so we
  // disable TSAN for these reads and writes using annotations.
  //
  // We don't use relaxed atomics here, as it is not a requirement of the
  // JavaScript memory model to have tear-free reads of overlapping accesses,
  // and using relaxed atomics may introduce overhead.
  TSAN_ANNOTATE_IGNORE_READS_BEGIN;
  auto result = ptr[index];
  TSAN_ANNOTATE_IGNORE_READS_END;
  return result;
}

template <class Traits>
void FixedTypedArray<Traits>::set(int index, ElementType value) {
  CHECK((index >= 0) && (index < this->length()));
  // See the comment in FixedTypedArray<Traits>::get_scalar.
  auto* ptr = reinterpret_cast<ElementType*>(DataPtr());
  TSAN_ANNOTATE_IGNORE_WRITES_BEGIN;
  ptr[index] = value;
  TSAN_ANNOTATE_IGNORE_WRITES_END;
}

template <class Traits>
typename Traits::ElementType FixedTypedArray<Traits>::from(int value) {
  return static_cast<ElementType>(value);
}

template <>
inline uint8_t FixedTypedArray<Uint8ClampedArrayTraits>::from(int value) {
  if (value < 0) return 0;
  if (value > 0xFF) return 0xFF;
  return static_cast<uint8_t>(value);
}

template <class Traits>
typename Traits::ElementType FixedTypedArray<Traits>::from(uint32_t value) {
  return static_cast<ElementType>(value);
}

template <>
inline uint8_t FixedTypedArray<Uint8ClampedArrayTraits>::from(uint32_t value) {
  // We need this special case for Uint32 -> Uint8Clamped, because the highest
  // Uint32 values will be negative as an int, clamping to 0, rather than 255.
  if (value > 0xFF) return 0xFF;
  return static_cast<uint8_t>(value);
}

template <class Traits>
typename Traits::ElementType FixedTypedArray<Traits>::from(double value) {
  return static_cast<ElementType>(DoubleToInt32(value));
}

template <>
inline uint8_t FixedTypedArray<Uint8ClampedArrayTraits>::from(double value) {
  // Handle NaNs and less than zero values which clamp to zero.
  if (!(value > 0)) return 0;
  if (value > 0xFF) return 0xFF;
  return static_cast<uint8_t>(lrint(value));
}

template <>
inline float FixedTypedArray<Float32ArrayTraits>::from(double value) {
  return static_cast<float>(value);
}

template <>
inline double FixedTypedArray<Float64ArrayTraits>::from(double value) {
  return value;
}

template <class Traits>
Handle<Object> FixedTypedArray<Traits>::get(FixedTypedArray<Traits>* array,
                                            int index) {
  return Traits::ToHandle(array->GetIsolate(), array->get_scalar(index));
}

template <class Traits>
void FixedTypedArray<Traits>::SetValue(uint32_t index, Object* value) {
  ElementType cast_value = Traits::defaultValue();
  if (value->IsSmi()) {
    int int_value = Smi::ToInt(value);
    cast_value = from(int_value);
  } else if (value->IsHeapNumber()) {
    double double_value = HeapNumber::cast(value)->value();
    cast_value = from(double_value);
  } else {
    // Clamp undefined to the default value. All other types have been
    // converted to a number type further up in the call chain.
    DCHECK(value->IsUndefined(GetIsolate()));
  }
  set(index, cast_value);
}

Handle<Object> Uint8ArrayTraits::ToHandle(Isolate* isolate, uint8_t scalar) {
  return handle(Smi::FromInt(scalar), isolate);
}

Handle<Object> Uint8ClampedArrayTraits::ToHandle(Isolate* isolate,
                                                 uint8_t scalar) {
  return handle(Smi::FromInt(scalar), isolate);
}

Handle<Object> Int8ArrayTraits::ToHandle(Isolate* isolate, int8_t scalar) {
  return handle(Smi::FromInt(scalar), isolate);
}

Handle<Object> Uint16ArrayTraits::ToHandle(Isolate* isolate, uint16_t scalar) {
  return handle(Smi::FromInt(scalar), isolate);
}

Handle<Object> Int16ArrayTraits::ToHandle(Isolate* isolate, int16_t scalar) {
  return handle(Smi::FromInt(scalar), isolate);
}

Handle<Object> Uint32ArrayTraits::ToHandle(Isolate* isolate, uint32_t scalar) {
  return isolate->factory()->NewNumberFromUint(scalar);
}

Handle<Object> Int32ArrayTraits::ToHandle(Isolate* isolate, int32_t scalar) {
  return isolate->factory()->NewNumberFromInt(scalar);
}

Handle<Object> Float32ArrayTraits::ToHandle(Isolate* isolate, float scalar) {
  return isolate->factory()->NewNumber(scalar);
}

Handle<Object> Float64ArrayTraits::ToHandle(Isolate* isolate, double scalar) {
  return isolate->factory()->NewNumber(scalar);
}

// static
template <class Traits>
STATIC_CONST_MEMBER_DEFINITION const InstanceType
    FixedTypedArray<Traits>::kInstanceType;

template <class Traits>
FixedTypedArray<Traits>* FixedTypedArray<Traits>::cast(Object* object) {
  SLOW_DCHECK(object->IsHeapObject() &&
              HeapObject::cast(object)->map()->instance_type() ==
                  Traits::kInstanceType);
  return reinterpret_cast<FixedTypedArray<Traits>*>(object);
}

template <class Traits>
const FixedTypedArray<Traits>* FixedTypedArray<Traits>::cast(
    const Object* object) {
  SLOW_DCHECK(object->IsHeapObject() &&
              HeapObject::cast(object)->map()->instance_type() ==
                  Traits::kInstanceType);
  return reinterpret_cast<FixedTypedArray<Traits>*>(object);
}

int TemplateList::length() const {
  return Smi::ToInt(FixedArray::cast(this)->get(kLengthIndex));
}

Object* TemplateList::get(int index) const {
  return FixedArray::cast(this)->get(kFirstElementIndex + index);
}

void TemplateList::set(int index, Object* value) {
  FixedArray::cast(this)->set(kFirstElementIndex + index, value);
}

}  // namespace internal
}  // namespace v8

#include "src/objects/object-macros-undef.h"

#endif  // V8_OBJECTS_FIXED_ARRAY_INL_H_