text: // Copyright 2012 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.
  //
  // Review notes:
  //
  // - The use of macros in these inline functions may seem superfluous
  // but it is absolutely needed to make sure gcc generates optimal
  // code. gcc is not happy when attempting to inline too deep.
  //
  
  #ifndef V8_OBJECTS_INL_H_
  #define V8_OBJECTS_INL_H_
  
  #include "src/base/atomicops.h"
  #include "src/base/bits.h"
  #include "src/contexts-inl.h"
  #include "src/conversions-inl.h"
  #include "src/factory.h"
  #include "src/field-index-inl.h"
  #include "src/field-type.h"
  #include "src/handles-inl.h"
  #include "src/heap/heap-inl.h"
  #include "src/heap/heap.h"
  #include "src/isolate.h"
  #include "src/isolate-inl.h"
  #include "src/layout-descriptor-inl.h"
  #include "src/lookup.h"
  #include "src/objects.h"
  #include "src/property.h"
  #include "src/prototype.h"
  #include "src/transitions-inl.h"
  #include "src/type-feedback-vector-inl.h"
  #include "src/v8memory.h"
  
  namespace v8 {
  namespace internal {
  
  PropertyDetails::PropertyDetails(Smi* smi) {
    value_ = smi->value();
  }
  
  
  Smi* PropertyDetails::AsSmi() const {
    // Ensure the upper 2 bits have the same value by sign extending it. This is
    // necessary to be able to use the 31st bit of the property details.
    int value = value_ << 1;
    return Smi::FromInt(value >> 1);
  }
  
  
  int PropertyDetails::field_width_in_words() const {
    DCHECK(location() == kField);
    if (!FLAG_unbox_double_fields) return 1;
    if (kDoubleSize == kPointerSize) return 1;
    return representation().IsDouble() ? kDoubleSize / kPointerSize : 1;
  }
  
  #define TYPE_CHECKER(type, instancetype)           \
    bool HeapObject::Is##type() const {              \
      return map()->instance_type() == instancetype; \
    }
  
  #define CAST_ACCESSOR(type)                       \
    type* type::cast(Object* object) {              \
      SLOW_DCHECK(object->Is##type());              \
      return reinterpret_cast<type*>(object);       \
    }                                               \
    const type* type::cast(const Object* object) {  \
      SLOW_DCHECK(object->Is##type());              \
      return reinterpret_cast<const type*>(object); \
    }
  
  
  #define INT_ACCESSORS(holder, name, offset)                                   \
    int holder::name() const { return READ_INT_FIELD(this, offset); }           \
    void holder::set_##name(int value) { WRITE_INT_FIELD(this, offset, value); }
  
  
  #define ACCESSORS(holder, name, type, offset)                                 \
    type* holder::name() const { return type::cast(READ_FIELD(this, offset)); } \
    void holder::set_##name(type* value, WriteBarrierMode mode) {               \
      WRITE_FIELD(this, offset, value);                                         \
      CONDITIONAL_WRITE_BARRIER(GetHeap(), this, offset, value, mode);          \
    }
  
  
  // Getter that returns a Smi as an int and writes an int as a Smi.
  #define SMI_ACCESSORS(holder, name, offset)             \
    int holder::name() const {                            \
      Object* value = READ_FIELD(this, offset);           \
      return Smi::cast(value)->value();                   \
    }                                                     \
    void holder::set_##name(int value) {                  \
      WRITE_FIELD(this, offset, Smi::FromInt(value));     \
    }
  
  #define SYNCHRONIZED_SMI_ACCESSORS(holder, name, offset)    \
    int holder::synchronized_##name() const {                 \
      Object* value = ACQUIRE_READ_FIELD(this, offset);       \
      return Smi::cast(value)->value();                       \
    }                                                         \
    void holder::synchronized_set_##name(int value) {         \
      RELEASE_WRITE_FIELD(this, offset, Smi::FromInt(value)); \
    }
  
  #define NOBARRIER_SMI_ACCESSORS(holder, name, offset)          \
    int holder::nobarrier_##name() const {                       \
      Object* value = NOBARRIER_READ_FIELD(this, offset);        \
      return Smi::cast(value)->value();                          \
    }                                                            \
    void holder::nobarrier_set_##name(int value) {               \
      NOBARRIER_WRITE_FIELD(this, offset, Smi::FromInt(value));  \
    }
  
  #define BOOL_GETTER(holder, field, name, offset)           \
    bool holder::name() const {                              \
      return BooleanBit::get(field(), offset);               \
    }                                                        \
  
  
  #define BOOL_ACCESSORS(holder, field, name, offset)        \
    bool holder::name() const {                              \
      return BooleanBit::get(field(), offset);               \
    }                                                        \
    void holder::set_##name(bool value) {                    \
      set_##field(BooleanBit::set(field(), offset, value));  \
    }
  
  bool HeapObject::IsFixedArrayBase() const {
    return IsFixedArray() || IsFixedDoubleArray() || IsFixedTypedArrayBase();
  }
  
  bool HeapObject::IsFixedArray() const {
    InstanceType instance_type = map()->instance_type();
    return instance_type == FIXED_ARRAY_TYPE ||
           instance_type == TRANSITION_ARRAY_TYPE;
  }
  
  
  // External objects are not extensible, so the map check is enough.
  bool HeapObject::IsExternal() const {
    return map() == GetHeap()->external_map();
  }
  
  
  TYPE_CHECKER(HeapNumber, HEAP_NUMBER_TYPE)
  TYPE_CHECKER(MutableHeapNumber, MUTABLE_HEAP_NUMBER_TYPE)
  TYPE_CHECKER(Symbol, SYMBOL_TYPE)
  TYPE_CHECKER(Simd128Value, SIMD128_VALUE_TYPE)
  
  #define SIMD128_TYPE_CHECKER(TYPE, Type, type, lane_count, lane_type) \
    bool HeapObject::Is##Type() const { return map() == GetHeap()->type##_map(); }
  SIMD128_TYPES(SIMD128_TYPE_CHECKER)
  #undef SIMD128_TYPE_CHECKER
  
  #define IS_TYPE_FUNCTION_DEF(type_)                               \
    bool Object::Is##type_() const {                                \
      return IsHeapObject() && HeapObject::cast(this)->Is##type_(); \
    }
  HEAP_OBJECT_TYPE_LIST(IS_TYPE_FUNCTION_DEF)
  ODDBALL_LIST(IS_TYPE_FUNCTION_DEF)
  #undef IS_TYPE_FUNCTION_DEF
  
  bool HeapObject::IsString() const {
    return map()->instance_type() < FIRST_NONSTRING_TYPE;
  }
  
  bool HeapObject::IsName() const {
    return map()->instance_type() <= LAST_NAME_TYPE;
  }
  
  bool HeapObject::IsUniqueName() const {
    return IsInternalizedString() || IsSymbol();
  }
  
  bool Name::IsUniqueName() const {
    uint32_t type = map()->instance_type();
    return (type & (kIsNotStringMask | kIsNotInternalizedMask)) !=
           (kStringTag | kNotInternalizedTag);
  }
  
  bool HeapObject::IsFunction() const {
    STATIC_ASSERT(LAST_FUNCTION_TYPE == LAST_TYPE);
    return map()->instance_type() >= FIRST_FUNCTION_TYPE;
  }
  
  bool HeapObject::IsCallable() const { return map()->is_callable(); }
  
  bool HeapObject::IsConstructor() const { return map()->is_constructor(); }
  
  bool HeapObject::IsTemplateInfo() const {
    return IsObjectTemplateInfo() || IsFunctionTemplateInfo();
  }
  
  bool HeapObject::IsInternalizedString() const {
    uint32_t type = map()->instance_type();
    STATIC_ASSERT(kNotInternalizedTag != 0);
    return (type & (kIsNotStringMask | kIsNotInternalizedMask)) ==
        (kStringTag | kInternalizedTag);
  }
  
  bool HeapObject::IsConsString() const {
    if (!IsString()) return false;
    return StringShape(String::cast(this)).IsCons();
  }
  
  bool HeapObject::IsSlicedString() const {
    if (!IsString()) return false;
    return StringShape(String::cast(this)).IsSliced();
  }
  
  bool HeapObject::IsSeqString() const {
    if (!IsString()) return false;
    return StringShape(String::cast(this)).IsSequential();
  }
  
  bool HeapObject::IsSeqOneByteString() const {
    if (!IsString()) return false;
    return StringShape(String::cast(this)).IsSequential() &&
           String::cast(this)->IsOneByteRepresentation();
  }
  
  bool HeapObject::IsSeqTwoByteString() const {
    if (!IsString()) return false;
    return StringShape(String::cast(this)).IsSequential() &&
           String::cast(this)->IsTwoByteRepresentation();
  }
  
  bool HeapObject::IsExternalString() const {
    if (!IsString()) return false;
    return StringShape(String::cast(this)).IsExternal();
  }
  
  bool HeapObject::IsExternalOneByteString() const {
    if (!IsString()) return false;
    return StringShape(String::cast(this)).IsExternal() &&
           String::cast(this)->IsOneByteRepresentation();
  }
  
  bool HeapObject::IsExternalTwoByteString() const {
    if (!IsString()) return false;
    return StringShape(String::cast(this)).IsExternal() &&
           String::cast(this)->IsTwoByteRepresentation();
  }
  
  
  bool Object::HasValidElements() {
    // Dictionary is covered under FixedArray.
    return IsFixedArray() || IsFixedDoubleArray() || IsFixedTypedArrayBase();
  }
  
  
  bool Object::KeyEquals(Object* second) {
    Object* first = this;
    if (second->IsNumber()) {
      if (first->IsNumber()) return first->Number() == second->Number();
      Object* temp = first;
      first = second;
      second = temp;
    }
    if (first->IsNumber()) {
      DCHECK_LE(0, first->Number());
      uint32_t expected = static_cast<uint32_t>(first->Number());
      uint32_t index;
      return Name::cast(second)->AsArrayIndex(&index) && index == expected;
    }
    return Name::cast(first)->Equals(Name::cast(second));
  }
  
  
  bool Object::FilterKey(PropertyFilter filter) {
    if (IsSymbol()) {
      if (filter & SKIP_SYMBOLS) return true;
      if (Symbol::cast(this)->is_private()) return true;
    } else {
      if (filter & SKIP_STRINGS) return true;
    }
    return false;
  }
  
  
  Handle<Object> Object::NewStorageFor(Isolate* isolate,
                                       Handle<Object> object,
                                       Representation representation) {
    if (representation.IsSmi() && object->IsUninitialized()) {
      return handle(Smi::FromInt(0), isolate);
    }
    if (!representation.IsDouble()) return object;
    double value;
    if (object->IsUninitialized()) {
      value = 0;
    } else if (object->IsMutableHeapNumber()) {
      value = HeapNumber::cast(*object)->value();
    } else {
      value = object->Number();
    }
    return isolate->factory()->NewHeapNumber(value, MUTABLE);
  }
  
  
  Handle<Object> Object::WrapForRead(Isolate* isolate,
                                     Handle<Object> object,
                                     Representation representation) {
    DCHECK(!object->IsUninitialized());
    if (!representation.IsDouble()) {
      DCHECK(object->FitsRepresentation(representation));
      return object;
    }
    return isolate->factory()->NewHeapNumber(HeapNumber::cast(*object)->value());
  }
  
  
  StringShape::StringShape(const String* str)
    : type_(str->map()->instance_type()) {
    set_valid();
    DCHECK((type_ & kIsNotStringMask) == kStringTag);
  }
  
  
  StringShape::StringShape(Map* map)
    : type_(map->instance_type()) {
    set_valid();
    DCHECK((type_ & kIsNotStringMask) == kStringTag);
  }
  
  
  StringShape::StringShape(InstanceType t)
    : type_(static_cast<uint32_t>(t)) {
    set_valid();
    DCHECK((type_ & kIsNotStringMask) == kStringTag);
  }
  
  
  bool StringShape::IsInternalized() {
    DCHECK(valid());
    STATIC_ASSERT(kNotInternalizedTag != 0);
    return (type_ & (kIsNotStringMask | kIsNotInternalizedMask)) ==
        (kStringTag | kInternalizedTag);
  }
  
  
  bool String::IsOneByteRepresentation() const {
    uint32_t type = map()->instance_type();
    return (type & kStringEncodingMask) == kOneByteStringTag;
  }
  
  
  bool String::IsTwoByteRepresentation() const {
    uint32_t type = map()->instance_type();
    return (type & kStringEncodingMask) == kTwoByteStringTag;
  }
  
  
  bool String::IsOneByteRepresentationUnderneath() {
    uint32_t type = map()->instance_type();
    STATIC_ASSERT(kIsIndirectStringTag != 0);
    STATIC_ASSERT((kIsIndirectStringMask & kStringEncodingMask) == 0);
    DCHECK(IsFlat());
    switch (type & (kIsIndirectStringMask | kStringEncodingMask)) {
      case kOneByteStringTag:
        return true;
      case kTwoByteStringTag:
        return false;
      default:  // Cons or sliced string.  Need to go deeper.
        return GetUnderlying()->IsOneByteRepresentation();
    }
  }
  
  
  bool String::IsTwoByteRepresentationUnderneath() {
    uint32_t type = map()->instance_type();
    STATIC_ASSERT(kIsIndirectStringTag != 0);
    STATIC_ASSERT((kIsIndirectStringMask & kStringEncodingMask) == 0);
    DCHECK(IsFlat());
    switch (type & (kIsIndirectStringMask | kStringEncodingMask)) {
      case kOneByteStringTag:
        return false;
      case kTwoByteStringTag:
        return true;
      default:  // Cons or sliced string.  Need to go deeper.
        return GetUnderlying()->IsTwoByteRepresentation();
    }
  }
  
  
  bool String::HasOnlyOneByteChars() {
    uint32_t type = map()->instance_type();
    return (type & kOneByteDataHintMask) == kOneByteDataHintTag ||
           IsOneByteRepresentation();
  }
  
  
  bool StringShape::IsCons() {
    return (type_ & kStringRepresentationMask) == kConsStringTag;
  }
  
  
  bool StringShape::IsSliced() {
    return (type_ & kStringRepresentationMask) == kSlicedStringTag;
  }
  
  
  bool StringShape::IsIndirect() {
    return (type_ & kIsIndirectStringMask) == kIsIndirectStringTag;
  }
  
  
  bool StringShape::IsExternal() {
    return (type_ & kStringRepresentationMask) == kExternalStringTag;
  }
  
  
  bool StringShape::IsSequential() {
    return (type_ & kStringRepresentationMask) == kSeqStringTag;
  }
  
  
  StringRepresentationTag StringShape::representation_tag() {
    uint32_t tag = (type_ & kStringRepresentationMask);
    return static_cast<StringRepresentationTag>(tag);
  }
  
  
  uint32_t StringShape::encoding_tag() {
    return type_ & kStringEncodingMask;
  }
  
  
  uint32_t StringShape::full_representation_tag() {
    return (type_ & (kStringRepresentationMask | kStringEncodingMask));
  }
  
  
  STATIC_ASSERT((kStringRepresentationMask | kStringEncodingMask) ==
               Internals::kFullStringRepresentationMask);
  
  STATIC_ASSERT(static_cast<uint32_t>(kStringEncodingMask) ==
               Internals::kStringEncodingMask);
  
  
  bool StringShape::IsSequentialOneByte() {
    return full_representation_tag() == (kSeqStringTag | kOneByteStringTag);
  }
  
  
  bool StringShape::IsSequentialTwoByte() {
    return full_representation_tag() == (kSeqStringTag | kTwoByteStringTag);
  }
  
  
  bool StringShape::IsExternalOneByte() {
    return full_representation_tag() == (kExternalStringTag | kOneByteStringTag);
  }
  
  
  STATIC_ASSERT((kExternalStringTag | kOneByteStringTag) ==
                Internals::kExternalOneByteRepresentationTag);
  
  STATIC_ASSERT(v8::String::ONE_BYTE_ENCODING == kOneByteStringTag);
  
  
  bool StringShape::IsExternalTwoByte() {
    return full_representation_tag() == (kExternalStringTag | kTwoByteStringTag);
  }
  
  
  STATIC_ASSERT((kExternalStringTag | kTwoByteStringTag) ==
               Internals::kExternalTwoByteRepresentationTag);
  
  STATIC_ASSERT(v8::String::TWO_BYTE_ENCODING == kTwoByteStringTag);
  
  
  uc32 FlatStringReader::Get(int index) {
    if (is_one_byte_) {
      return Get<uint8_t>(index);
    } else {
      return Get<uc16>(index);
    }
  }
  
  
  template <typename Char>
  Char FlatStringReader::Get(int index) {
    DCHECK_EQ(is_one_byte_, sizeof(Char) == 1);
    DCHECK(0 <= index && index <= length_);
    if (sizeof(Char) == 1) {
      return static_cast<Char>(static_cast<const uint8_t*>(start_)[index]);
    } else {
      return static_cast<Char>(static_cast<const uc16*>(start_)[index]);
    }
  }
  
  
  Handle<Object> StringTableShape::AsHandle(Isolate* isolate, HashTableKey* key) {
    return key->AsHandle(isolate);
  }
  
  
  Handle<Object> CompilationCacheShape::AsHandle(Isolate* isolate,
                                                 HashTableKey* key) {
    return key->AsHandle(isolate);
  }
  
  
  Handle<Object> CodeCacheHashTableShape::AsHandle(Isolate* isolate,
                                                   HashTableKey* key) {
    return key->AsHandle(isolate);
  }
  
  template <typename Char>
  class SequentialStringKey : public HashTableKey {
   public:
    explicit SequentialStringKey(Vector<const Char> string, uint32_t seed)
        : string_(string), hash_field_(0), seed_(seed) { }
  
    uint32_t Hash() override {
      hash_field_ = StringHasher::HashSequentialString<Char>(string_.start(),
                                                             string_.length(),
                                                             seed_);
  
      uint32_t result = hash_field_ >> String::kHashShift;
      DCHECK(result != 0);  // Ensure that the hash value of 0 is never computed.
      return result;
    }
  
  
    uint32_t HashForObject(Object* other) override {
      return String::cast(other)->Hash();
    }
  
    Vector<const Char> string_;
    uint32_t hash_field_;
    uint32_t seed_;
  };
  
  
  class OneByteStringKey : public SequentialStringKey<uint8_t> {
   public:
    OneByteStringKey(Vector<const uint8_t> str, uint32_t seed)
        : SequentialStringKey<uint8_t>(str, seed) { }
  
    bool IsMatch(Object* string) override {
      return String::cast(string)->IsOneByteEqualTo(string_);
    }
  
    Handle<Object> AsHandle(Isolate* isolate) override;
  };
  
  
  class SeqOneByteSubStringKey : public HashTableKey {
   public:
    SeqOneByteSubStringKey(Handle<SeqOneByteString> string, int from, int length)
        : string_(string), from_(from), length_(length) {
      DCHECK(string_->IsSeqOneByteString());
    }
  
    uint32_t Hash() override {
      DCHECK(length_ >= 0);
      DCHECK(from_ + length_ <= string_->length());
      const uint8_t* chars = string_->GetChars() + from_;
      hash_field_ = StringHasher::HashSequentialString(
          chars, length_, string_->GetHeap()->HashSeed());
      uint32_t result = hash_field_ >> String::kHashShift;
      DCHECK(result != 0);  // Ensure that the hash value of 0 is never computed.
      return result;
    }
  
    uint32_t HashForObject(Object* other) override {
      return String::cast(other)->Hash();
    }
  
    bool IsMatch(Object* string) override;
    Handle<Object> AsHandle(Isolate* isolate) override;
  
   private:
    Handle<SeqOneByteString> string_;
    int from_;
    int length_;
    uint32_t hash_field_;
  };
  
  
  class TwoByteStringKey : public SequentialStringKey<uc16> {
   public:
    explicit TwoByteStringKey(Vector<const uc16> str, uint32_t seed)
        : SequentialStringKey<uc16>(str, seed) { }
  
    bool IsMatch(Object* string) override {
      return String::cast(string)->IsTwoByteEqualTo(string_);
    }
  
    Handle<Object> AsHandle(Isolate* isolate) override;
  };
  
  
  // Utf8StringKey carries a vector of chars as key.
  class Utf8StringKey : public HashTableKey {
   public:
    explicit Utf8StringKey(Vector<const char> string, uint32_t seed)
        : string_(string), hash_field_(0), seed_(seed) { }
  
    bool IsMatch(Object* string) override {
      return String::cast(string)->IsUtf8EqualTo(string_);
    }
  
    uint32_t Hash() override {
      if (hash_field_ != 0) return hash_field_ >> String::kHashShift;
      hash_field_ = StringHasher::ComputeUtf8Hash(string_, seed_, &chars_);
      uint32_t result = hash_field_ >> String::kHashShift;
      DCHECK(result != 0);  // Ensure that the hash value of 0 is never computed.
      return result;
    }
  
    uint32_t HashForObject(Object* other) override {
      return String::cast(other)->Hash();
    }
  
    Handle<Object> AsHandle(Isolate* isolate) override {
      if (hash_field_ == 0) Hash();
      return isolate->factory()->NewInternalizedStringFromUtf8(
          string_, chars_, hash_field_);
    }
  
    Vector<const char> string_;
    uint32_t hash_field_;
    int chars_;  // Caches the number of characters when computing the hash code.
    uint32_t seed_;
  };
  
  
  bool Object::IsNumber() const {
    return IsSmi() || IsHeapNumber();
  }
  
  
  TYPE_CHECKER(ByteArray, BYTE_ARRAY_TYPE)
  TYPE_CHECKER(BytecodeArray, BYTECODE_ARRAY_TYPE)
  TYPE_CHECKER(FreeSpace, FREE_SPACE_TYPE)
  
  bool HeapObject::IsFiller() const {
    InstanceType instance_type = map()->instance_type();
    return instance_type == FREE_SPACE_TYPE || instance_type == FILLER_TYPE;
  }
  
  
  
  #define TYPED_ARRAY_TYPE_CHECKER(Type, type, TYPE, ctype, size)               \
    TYPE_CHECKER(Fixed##Type##Array, FIXED_##TYPE##_ARRAY_TYPE)
  
  TYPED_ARRAYS(TYPED_ARRAY_TYPE_CHECKER)
  #undef TYPED_ARRAY_TYPE_CHECKER
  
  bool HeapObject::IsFixedTypedArrayBase() const {
    InstanceType instance_type = map()->instance_type();
    return (instance_type >= FIRST_FIXED_TYPED_ARRAY_TYPE &&
            instance_type <= LAST_FIXED_TYPED_ARRAY_TYPE);
  }
  
  bool HeapObject::IsJSReceiver() const {
    STATIC_ASSERT(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
    return map()->instance_type() >= FIRST_JS_RECEIVER_TYPE;
  }
  
  bool HeapObject::IsJSObject() const {
    STATIC_ASSERT(LAST_JS_OBJECT_TYPE == LAST_TYPE);
    return map()->IsJSObjectMap();
  }
  
  bool HeapObject::IsJSProxy() const { return map()->IsJSProxyMap(); }
  
  TYPE_CHECKER(JSSet, JS_SET_TYPE)
  TYPE_CHECKER(JSMap, JS_MAP_TYPE)
  TYPE_CHECKER(JSSetIterator, JS_SET_ITERATOR_TYPE)
  TYPE_CHECKER(JSMapIterator, JS_MAP_ITERATOR_TYPE)
  TYPE_CHECKER(JSWeakMap, JS_WEAK_MAP_TYPE)
  TYPE_CHECKER(JSWeakSet, JS_WEAK_SET_TYPE)
  TYPE_CHECKER(JSContextExtensionObject, JS_CONTEXT_EXTENSION_OBJECT_TYPE)
  TYPE_CHECKER(Map, MAP_TYPE)
  TYPE_CHECKER(FixedDoubleArray, FIXED_DOUBLE_ARRAY_TYPE)
  TYPE_CHECKER(WeakFixedArray, FIXED_ARRAY_TYPE)
  TYPE_CHECKER(TransitionArray, TRANSITION_ARRAY_TYPE)
  
  bool HeapObject::IsJSWeakCollection() const {
    return IsJSWeakMap() || IsJSWeakSet();
  }
  
  bool HeapObject::IsDescriptorArray() const { return IsFixedArray(); }
  
  bool HeapObject::IsArrayList() const { return IsFixedArray(); }
  
  bool Object::IsLayoutDescriptor() const {
    return IsSmi() || IsFixedTypedArrayBase();
  }
  
  bool HeapObject::IsTypeFeedbackVector() const { return IsFixedArray(); }
  
  bool HeapObject::IsTypeFeedbackMetadata() const { return IsFixedArray(); }
  
  bool HeapObject::IsLiteralsArray() const { return IsFixedArray(); }
  
  bool HeapObject::IsDeoptimizationInputData() const {
    // Must be a fixed array.
    if (!IsFixedArray()) return false;
  
    // There's no sure way to detect the difference between a fixed array and
    // a deoptimization data array.  Since this is used for asserts we can
    // check that the length is zero or else the fixed size plus a multiple of
    // the entry size.
    int length = FixedArray::cast(this)->length();
    if (length == 0) return true;
  
    length -= DeoptimizationInputData::kFirstDeoptEntryIndex;
    return length >= 0 && length % DeoptimizationInputData::kDeoptEntrySize == 0;
  }
  
  bool HeapObject::IsDeoptimizationOutputData() const {
    if (!IsFixedArray()) return false;
    // There's actually no way to see the difference between a fixed array and
    // a deoptimization data array.  Since this is used for asserts we can check
    // that the length is plausible though.
    if (FixedArray::cast(this)->length() % 2 != 0) return false;
    return true;
  }
  
  bool HeapObject::IsHandlerTable() const {
    if (!IsFixedArray()) return false;
    // There's actually no way to see the difference between a fixed array and
    // a handler table array.
    return true;
  }
  
  bool HeapObject::IsDependentCode() const {
    if (!IsFixedArray()) return false;
    // There's actually no way to see the difference between a fixed array and
    // a dependent codes array.
    return true;
  }
  
  bool HeapObject::IsContext() const {
    Map* map = this->map();
    Heap* heap = GetHeap();
    return (
        map == heap->function_context_map() || map == heap->catch_context_map() ||
        map == heap->with_context_map() || map == heap->native_context_map() ||
        map == heap->block_context_map() || map == heap->module_context_map() ||
        map == heap->script_context_map() ||
        map == heap->debug_evaluate_context_map());
  }
  
  bool HeapObject::IsNativeContext() const {
    return map() == GetHeap()->native_context_map();
  }
  
  bool HeapObject::IsScriptContextTable() const {
    return map() == GetHeap()->script_context_table_map();
  }
  
  bool HeapObject::IsScopeInfo() const {
    return map() == GetHeap()->scope_info_map();
  }
  
  
  TYPE_CHECKER(JSBoundFunction, JS_BOUND_FUNCTION_TYPE)
  TYPE_CHECKER(JSFunction, JS_FUNCTION_TYPE)
  
  
  template <> inline bool Is<JSFunction>(Object* obj) {
    return obj->IsJSFunction();
  }
  
  
  TYPE_CHECKER(Code, CODE_TYPE)
  TYPE_CHECKER(Oddball, ODDBALL_TYPE)
  TYPE_CHECKER(Cell, CELL_TYPE)
  TYPE_CHECKER(PropertyCell, PROPERTY_CELL_TYPE)
  TYPE_CHECKER(WeakCell, WEAK_CELL_TYPE)
  TYPE_CHECKER(SharedFunctionInfo, SHARED_FUNCTION_INFO_TYPE)
  TYPE_CHECKER(JSGeneratorObject, JS_GENERATOR_OBJECT_TYPE)
  TYPE_CHECKER(JSModule, JS_MODULE_TYPE)
  TYPE_CHECKER(JSValue, JS_VALUE_TYPE)
  TYPE_CHECKER(JSDate, JS_DATE_TYPE)
  TYPE_CHECKER(JSMessageObject, JS_MESSAGE_OBJECT_TYPE)
  
  bool HeapObject::IsAbstractCode() const {
    return IsBytecodeArray() || IsCode();
  }
  
  bool HeapObject::IsStringWrapper() const {
    return IsJSValue() && JSValue::cast(this)->value()->IsString();
  }
  
  
  TYPE_CHECKER(Foreign, FOREIGN_TYPE)
  
  bool HeapObject::IsBoolean() const {
    return IsOddball() &&
        ((Oddball::cast(this)->kind() & Oddball::kNotBooleanMask) == 0);
  }
  
  
  TYPE_CHECKER(JSArray, JS_ARRAY_TYPE)
  TYPE_CHECKER(JSArrayBuffer, JS_ARRAY_BUFFER_TYPE)
  TYPE_CHECKER(JSTypedArray, JS_TYPED_ARRAY_TYPE)
  TYPE_CHECKER(JSDataView, JS_DATA_VIEW_TYPE)
  
  bool HeapObject::IsJSArrayBufferView() const {
    return IsJSDataView() || IsJSTypedArray();
  }
  
  
  TYPE_CHECKER(JSRegExp, JS_REGEXP_TYPE)
  
  
  template <> inline bool Is<JSArray>(Object* obj) {
    return obj->IsJSArray();
  }
  
  bool HeapObject::IsHashTable() const {
    return map() == GetHeap()->hash_table_map();
  }
  
  bool HeapObject::IsWeakHashTable() const { return IsHashTable(); }
  
  bool HeapObject::IsDictionary() const {
    return IsHashTable() && this != GetHeap()->string_table();
  }
  
  
  bool Object::IsNameDictionary() const {
    return IsDictionary();
  }
  
  
  bool Object::IsGlobalDictionary() const { return IsDictionary(); }
  
  
  bool Object::IsSeededNumberDictionary() const {
    return IsDictionary();
  }
  
  
  bool Object::IsUnseededNumberDictionary() const {
    return IsDictionary();
  }
  
  bool HeapObject::IsStringTable() const { return IsHashTable(); }
  
  bool HeapObject::IsStringSet() const { return IsHashTable(); }
  
  bool HeapObject::IsNormalizedMapCache() const {
    return NormalizedMapCache::IsNormalizedMapCache(this);
  }
  
  
  int NormalizedMapCache::GetIndex(Handle<Map> map) {
    return map->Hash() % NormalizedMapCache::kEntries;
  }
  
  bool NormalizedMapCache::IsNormalizedMapCache(const HeapObject* obj) {
    if (!obj->IsFixedArray()) return false;
    if (FixedArray::cast(obj)->length() != NormalizedMapCache::kEntries) {
      return false;
    }
  #ifdef VERIFY_HEAP
    if (FLAG_verify_heap) {
      reinterpret_cast<NormalizedMapCache*>(const_cast<HeapObject*>(obj))
          ->NormalizedMapCacheVerify();
    }
  #endif
    return true;
  }
  
  bool HeapObject::IsCompilationCacheTable() const { return IsHashTable(); }
  
  bool HeapObject::IsCodeCacheHashTable() const { return IsHashTable(); }
  
  bool HeapObject::IsPolymorphicCodeCacheHashTable() const {
    return IsHashTable();
  }
  
  bool HeapObject::IsMapCache() const { return IsHashTable(); }
  
  bool HeapObject::IsObjectHashTable() const { return IsHashTable(); }
  
  bool HeapObject::IsOrderedHashTable() const {
    return map() == GetHeap()->ordered_hash_table_map();
  }
  
  
  bool Object::IsOrderedHashSet() const {
    return IsOrderedHashTable();
  }
  
  
  bool Object::IsOrderedHashMap() const {
    return IsOrderedHashTable();
  }
  
  
  bool Object::IsPrimitive() const {
    return IsSmi() || HeapObject::cast(this)->map()->IsPrimitiveMap();
  }
  
  bool HeapObject::IsJSGlobalProxy() const {
    bool result = map()->instance_type() == JS_GLOBAL_PROXY_TYPE;
    DCHECK(!result || map()->is_access_check_needed());
    return result;
  }
  
  
  TYPE_CHECKER(JSGlobalObject, JS_GLOBAL_OBJECT_TYPE)
  
  bool HeapObject::IsUndetectable() const { return map()->is_undetectable(); }
  
  bool HeapObject::IsAccessCheckNeeded() const {
    if (IsJSGlobalProxy()) {
      const JSGlobalProxy* proxy = JSGlobalProxy::cast(this);
      JSGlobalObject* global = proxy->GetIsolate()->context()->global_object();
      return proxy->IsDetachedFrom(global);
    }
    return map()->is_access_check_needed();
  }
  
  bool HeapObject::IsStruct() const {
    switch (map()->instance_type()) {
  #define MAKE_STRUCT_CASE(NAME, Name, name) case NAME##_TYPE: return true;
    STRUCT_LIST(MAKE_STRUCT_CASE)
  #undef MAKE_STRUCT_CASE
      default: return false;
    }
  }
  
  #define MAKE_STRUCT_PREDICATE(NAME, Name, name)                  \
    bool Object::Is##Name() const {                                \
      return IsHeapObject() && HeapObject::cast(this)->Is##Name(); \
    }                                                              \
    bool HeapObject::Is##Name() const {                            \
      return map()->instance_type() == NAME##_TYPE;                \
    }
  STRUCT_LIST(MAKE_STRUCT_PREDICATE)
  #undef MAKE_STRUCT_PREDICATE
  
  #define MAKE_ODDBALL_PREDICATE(Name)                                       \
    bool HeapObject::Is##Name() const {                                      \
      return IsOddball() && Oddball::cast(this)->kind() == Oddball::k##Name; \
    }
  ODDBALL_LIST(MAKE_ODDBALL_PREDICATE)
  
  #undef MAKE_ODDBALL_PREDICATE
  double Object::Number() const {
    DCHECK(IsNumber());
    return IsSmi()
               ? static_cast<double>(reinterpret_cast<const Smi*>(this)->value())
               : reinterpret_cast<const HeapNumber*>(this)->value();
  }
  
  
  bool Object::IsNaN() const {
    return this->IsHeapNumber() && std::isnan(HeapNumber::cast(this)->value());
  }
  
  
  bool Object::IsMinusZero() const {
    return this->IsHeapNumber() &&
           i::IsMinusZero(HeapNumber::cast(this)->value());
  }
  
  
  Representation Object::OptimalRepresentation() {
    if (!FLAG_track_fields) return Representation::Tagged();
    if (IsSmi()) {
      return Representation::Smi();
    } else if (FLAG_track_double_fields && IsHeapNumber()) {
      return Representation::Double();
    } else if (FLAG_track_computed_fields && IsUninitialized()) {
      return Representation::None();
    } else if (FLAG_track_heap_object_fields) {
      DCHECK(IsHeapObject());
      return Representation::HeapObject();
    } else {
      return Representation::Tagged();
    }
  }
  
  
  ElementsKind Object::OptimalElementsKind() {
    if (IsSmi()) return FAST_SMI_ELEMENTS;
    if (IsNumber()) return FAST_DOUBLE_ELEMENTS;
    return FAST_ELEMENTS;
  }
  
  
  bool Object::FitsRepresentation(Representation representation) {
    if (FLAG_track_fields && representation.IsSmi()) {
      return IsSmi();
    } else if (FLAG_track_double_fields && representation.IsDouble()) {
      return IsMutableHeapNumber() || IsNumber();
    } else if (FLAG_track_heap_object_fields && representation.IsHeapObject()) {
      return IsHeapObject();
    } else if (FLAG_track_fields && representation.IsNone()) {
      return false;
    }
    return true;
  }
  
  bool Object::ToUint32(uint32_t* value) {
    if (IsSmi()) {
      int num = Smi::cast(this)->value();
      if (num < 0) return false;
      *value = static_cast<uint32_t>(num);
      return true;
    }
    if (IsHeapNumber()) {
      double num = HeapNumber::cast(this)->value();
      if (num < 0) return false;
      uint32_t uint_value = FastD2UI(num);
      if (FastUI2D(uint_value) == num) {
        *value = uint_value;
        return true;
      }
    }
    return false;
  }
  
  // static
  MaybeHandle<JSReceiver> Object::ToObject(Isolate* isolate,
                                           Handle<Object> object) {
    if (object->IsJSReceiver()) return Handle<JSReceiver>::cast(object);
    return ToObject(isolate, object, isolate->native_context());
  }
  
  
  // static
  MaybeHandle<Name> Object::ToName(Isolate* isolate, Handle<Object> input) {
    if (input->IsName()) return Handle<Name>::cast(input);
    return ConvertToName(isolate, input);
  }
  
  // static
  MaybeHandle<Object> Object::ToPrimitive(Handle<Object> input,
                                          ToPrimitiveHint hint) {
    if (input->IsPrimitive()) return input;
    return JSReceiver::ToPrimitive(Handle<JSReceiver>::cast(input), hint);
  }
  
  
  bool Object::HasSpecificClassOf(String* name) {
    return this->IsJSObject() && (JSObject::cast(this)->class_name() == name);
  }
  
  MaybeHandle<Object> Object::GetProperty(Handle<Object> object,
                                          Handle<Name> name) {
    LookupIterator it(object, name);
    if (!it.IsFound()) return it.factory()->undefined_value();
    return GetProperty(&it);
  }
  
  MaybeHandle<Object> JSReceiver::GetProperty(Handle<JSReceiver> receiver,
                                              Handle<Name> name) {
    LookupIterator it(receiver, name, receiver);
    if (!it.IsFound()) return it.factory()->undefined_value();
    return Object::GetProperty(&it);
  }
  
  MaybeHandle<Object> Object::GetElement(Isolate* isolate, Handle<Object> object,
                                         uint32_t index) {
    LookupIterator it(isolate, object, index);
    if (!it.IsFound()) return it.factory()->undefined_value();
    return GetProperty(&it);
  }
  
  MaybeHandle<Object> JSReceiver::GetElement(Isolate* isolate,
                                             Handle<JSReceiver> receiver,
                                             uint32_t index) {
    LookupIterator it(isolate, receiver, index, receiver);
    if (!it.IsFound()) return it.factory()->undefined_value();
    return Object::GetProperty(&it);
  }
  
  Handle<Object> JSReceiver::GetDataProperty(Handle<JSReceiver> object,
                                             Handle<Name> name) {
    LookupIterator it(object, name, object,
                      LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
    if (!it.IsFound()) return it.factory()->undefined_value();
    return GetDataProperty(&it);
  }
  
  MaybeHandle<Object> Object::SetElement(Isolate* isolate, Handle<Object> object,
                                         uint32_t index, Handle<Object> value,
                                         LanguageMode language_mode) {
    LookupIterator it(isolate, object, index);
    MAYBE_RETURN_NULL(
        SetProperty(&it, value, language_mode, MAY_BE_STORE_FROM_KEYED));
    return value;
  }
  
  MaybeHandle<Object> JSReceiver::GetPrototype(Isolate* isolate,
                                               Handle<JSReceiver> receiver) {
    // We don't expect access checks to be needed on JSProxy objects.
    DCHECK(!receiver->IsAccessCheckNeeded() || receiver->IsJSObject());
    PrototypeIterator iter(isolate, receiver,
                           PrototypeIterator::START_AT_RECEIVER,
                           PrototypeIterator::END_AT_NON_HIDDEN);
    do {
      if (!iter.AdvanceFollowingProxies()) return MaybeHandle<Object>();
    } while (!iter.IsAtEnd());
    return PrototypeIterator::GetCurrent(iter);
  }
  
  MaybeHandle<Object> JSReceiver::GetProperty(Isolate* isolate,
                                              Handle<JSReceiver> receiver,
                                              const char* name) {
    Handle<String> str = isolate->factory()->InternalizeUtf8String(name);
    return GetProperty(receiver, str);
  }
  
  
  #define FIELD_ADDR(p, offset) \
    (reinterpret_cast<byte*>(p) + offset - kHeapObjectTag)
  
  #define FIELD_ADDR_CONST(p, offset) \
    (reinterpret_cast<const byte*>(p) + offset - kHeapObjectTag)
  
  #define READ_FIELD(p, offset) \
    (*reinterpret_cast<Object* const*>(FIELD_ADDR_CONST(p, offset)))
  
  #define ACQUIRE_READ_FIELD(p, offset)           \
    reinterpret_cast<Object*>(base::Acquire_Load( \
        reinterpret_cast<const base::AtomicWord*>(FIELD_ADDR_CONST(p, offset))))
  
  #define NOBARRIER_READ_FIELD(p, offset)           \
    reinterpret_cast<Object*>(base::NoBarrier_Load( \
        reinterpret_cast<const base::AtomicWord*>(FIELD_ADDR_CONST(p, offset))))
  
  #define WRITE_FIELD(p, offset, value) \
    (*reinterpret_cast<Object**>(FIELD_ADDR(p, offset)) = value)
  
  #define RELEASE_WRITE_FIELD(p, offset, value)                     \
    base::Release_Store(                                            \
        reinterpret_cast<base::AtomicWord*>(FIELD_ADDR(p, offset)), \
        reinterpret_cast<base::AtomicWord>(value));
  
  #define NOBARRIER_WRITE_FIELD(p, offset, value)                   \
    base::NoBarrier_Store(                                          \
        reinterpret_cast<base::AtomicWord*>(FIELD_ADDR(p, offset)), \
        reinterpret_cast<base::AtomicWord>(value));
  
  #define WRITE_BARRIER(heap, object, offset, value)          \
    heap->incremental_marking()->RecordWrite(                 \
        object, HeapObject::RawField(object, offset), value); \
    heap->RecordWrite(object, offset, value);
  
  #define CONDITIONAL_WRITE_BARRIER(heap, object, offset, value, mode) \
    if (mode != SKIP_WRITE_BARRIER) {                                  \
      if (mode == UPDATE_WRITE_BARRIER) {                              \
        heap->incremental_marking()->RecordWrite(                      \
            object, HeapObject::RawField(object, offset), value);      \
      }                                                                \
      heap->RecordWrite(object, offset, value);                        \
    }
  
  #define READ_DOUBLE_FIELD(p, offset) \
    ReadDoubleValue(FIELD_ADDR_CONST(p, offset))
  
  #define WRITE_DOUBLE_FIELD(p, offset, value) \
    WriteDoubleValue(FIELD_ADDR(p, offset), value)
  
  #define READ_INT_FIELD(p, offset) \
    (*reinterpret_cast<const int*>(FIELD_ADDR_CONST(p, offset)))
  
  #define WRITE_INT_FIELD(p, offset, value) \
    (*reinterpret_cast<int*>(FIELD_ADDR(p, offset)) = value)
  
  #define READ_INTPTR_FIELD(p, offset) \
    (*reinterpret_cast<const intptr_t*>(FIELD_ADDR_CONST(p, offset)))
  
  #define WRITE_INTPTR_FIELD(p, offset, value) \
    (*reinterpret_cast<intptr_t*>(FIELD_ADDR(p, offset)) = value)
  
  #define READ_UINT8_FIELD(p, offset) \
    (*reinterpret_cast<const uint8_t*>(FIELD_ADDR_CONST(p, offset)))
  
  #define WRITE_UINT8_FIELD(p, offset, value) \
    (*reinterpret_cast<uint8_t*>(FIELD_ADDR(p, offset)) = value)
  
  #define READ_INT8_FIELD(p, offset) \
    (*reinterpret_cast<const int8_t*>(FIELD_ADDR_CONST(p, offset)))
  
  #define WRITE_INT8_FIELD(p, offset, value) \
    (*reinterpret_cast<int8_t*>(FIELD_ADDR(p, offset)) = value)
  
  #define READ_UINT16_FIELD(p, offset) \
    (*reinterpret_cast<const uint16_t*>(FIELD_ADDR_CONST(p, offset)))
  
  #define WRITE_UINT16_FIELD(p, offset, value) \
    (*reinterpret_cast<uint16_t*>(FIELD_ADDR(p, offset)) = value)
  
  #define READ_INT16_FIELD(p, offset) \
    (*reinterpret_cast<const int16_t*>(FIELD_ADDR_CONST(p, offset)))
  
  #define WRITE_INT16_FIELD(p, offset, value) \
    (*reinterpret_cast<int16_t*>(FIELD_ADDR(p, offset)) = value)
  
  #define READ_UINT32_FIELD(p, offset) \
    (*reinterpret_cast<const uint32_t*>(FIELD_ADDR_CONST(p, offset)))
  
  #define WRITE_UINT32_FIELD(p, offset, value) \
    (*reinterpret_cast<uint32_t*>(FIELD_ADDR(p, offset)) = value)
  
  #define READ_INT32_FIELD(p, offset) \
    (*reinterpret_cast<const int32_t*>(FIELD_ADDR_CONST(p, offset)))
  
  #define WRITE_INT32_FIELD(p, offset, value) \
    (*reinterpret_cast<int32_t*>(FIELD_ADDR(p, offset)) = value)
  
  #define READ_FLOAT_FIELD(p, offset) \
    (*reinterpret_cast<const float*>(FIELD_ADDR_CONST(p, offset)))
  
  #define WRITE_FLOAT_FIELD(p, offset, value) \
    (*reinterpret_cast<float*>(FIELD_ADDR(p, offset)) = value)
  
  #define READ_UINT64_FIELD(p, offset) \
    (*reinterpret_cast<const uint64_t*>(FIELD_ADDR_CONST(p, offset)))
  
  #define WRITE_UINT64_FIELD(p, offset, value) \
    (*reinterpret_cast<uint64_t*>(FIELD_ADDR(p, offset)) = value)
  
  #define READ_INT64_FIELD(p, offset) \
    (*reinterpret_cast<const int64_t*>(FIELD_ADDR_CONST(p, offset)))
  
  #define WRITE_INT64_FIELD(p, offset, value) \
    (*reinterpret_cast<int64_t*>(FIELD_ADDR(p, offset)) = value)
  
  #define READ_BYTE_FIELD(p, offset) \
    (*reinterpret_cast<const byte*>(FIELD_ADDR_CONST(p, offset)))
  
  #define NOBARRIER_READ_BYTE_FIELD(p, offset) \
    static_cast<byte>(base::NoBarrier_Load(    \
        reinterpret_cast<base::Atomic8*>(FIELD_ADDR(p, offset))))
  
  #define WRITE_BYTE_FIELD(p, offset, value) \
    (*reinterpret_cast<byte*>(FIELD_ADDR(p, offset)) = value)
  
  #define NOBARRIER_WRITE_BYTE_FIELD(p, offset, value)           \
    base::NoBarrier_Store(                                       \
        reinterpret_cast<base::Atomic8*>(FIELD_ADDR(p, offset)), \
        static_cast<base::Atomic8>(value));
  
  Object** HeapObject::RawField(HeapObject* obj, int byte_offset) {
    return reinterpret_cast<Object**>(FIELD_ADDR(obj, byte_offset));
  }
  
  
  MapWord MapWord::FromMap(const Map* map) {
    return MapWord(reinterpret_cast<uintptr_t>(map));
  }
  
  
  Map* MapWord::ToMap() {
    return reinterpret_cast<Map*>(value_);
  }
  
  
  bool MapWord::IsForwardingAddress() {
    return HAS_SMI_TAG(reinterpret_cast<Object*>(value_));
  }
  
  
  MapWord MapWord::FromForwardingAddress(HeapObject* object) {
    Address raw = reinterpret_cast<Address>(object) - kHeapObjectTag;
    return MapWord(reinterpret_cast<uintptr_t>(raw));
  }
  
  
  HeapObject* MapWord::ToForwardingAddress() {
    DCHECK(IsForwardingAddress());
    return HeapObject::FromAddress(reinterpret_cast<Address>(value_));
  }
  
  
  #ifdef VERIFY_HEAP
  void HeapObject::VerifyObjectField(int offset) {
    VerifyPointer(READ_FIELD(this, offset));
  }
  
  void HeapObject::VerifySmiField(int offset) {
    CHECK(READ_FIELD(this, offset)->IsSmi());
  }
  #endif
  
  
  Heap* HeapObject::GetHeap() const {
    Heap* heap = MemoryChunk::FromAddress(
                     reinterpret_cast<Address>(const_cast<HeapObject*>(this)))
                     ->heap();
    SLOW_DCHECK(heap != NULL);
    return heap;
  }
  
  
  Isolate* HeapObject::GetIsolate() const {
    return GetHeap()->isolate();
  }
  
  
  Map* HeapObject::map() const {
  #ifdef DEBUG
    // Clear mark potentially added by PathTracer.
    uintptr_t raw_value =
        map_word().ToRawValue() & ~static_cast<uintptr_t>(PathTracer::kMarkTag);
    return MapWord::FromRawValue(raw_value).ToMap();
  #else
    return map_word().ToMap();
  #endif
  }
  
  
  void HeapObject::set_map(Map* value) {
    set_map_word(MapWord::FromMap(value));
    if (value != NULL) {
      // TODO(1600) We are passing NULL as a slot because maps can never be on
      // evacuation candidate.
      value->GetHeap()->incremental_marking()->RecordWrite(this, NULL, value);
    }
  }
  
  
  Map* HeapObject::synchronized_map() {
    return synchronized_map_word().ToMap();
  }
  
  
  void HeapObject::synchronized_set_map(Map* value) {
    synchronized_set_map_word(MapWord::FromMap(value));
    if (value != NULL) {
      // TODO(1600) We are passing NULL as a slot because maps can never be on
      // evacuation candidate.
      value->GetHeap()->incremental_marking()->RecordWrite(this, NULL, value);
    }
  }
  
  
  void HeapObject::synchronized_set_map_no_write_barrier(Map* value) {
    synchronized_set_map_word(MapWord::FromMap(value));
  }
  
  
  // Unsafe accessor omitting write barrier.
  void HeapObject::set_map_no_write_barrier(Map* value) {
    set_map_word(MapWord::FromMap(value));
  }
  
  
  MapWord HeapObject::map_word() const {
    return MapWord(
        reinterpret_cast<uintptr_t>(NOBARRIER_READ_FIELD(this, kMapOffset)));
  }
  
  
  void HeapObject::set_map_word(MapWord map_word) {
    NOBARRIER_WRITE_FIELD(
        this, kMapOffset, reinterpret_cast<Object*>(map_word.value_));
  }
  
  
  MapWord HeapObject::synchronized_map_word() const {
    return MapWord(
        reinterpret_cast<uintptr_t>(ACQUIRE_READ_FIELD(this, kMapOffset)));
  }
  
  
  void HeapObject::synchronized_set_map_word(MapWord map_word) {
    RELEASE_WRITE_FIELD(
        this, kMapOffset, reinterpret_cast<Object*>(map_word.value_));
  }
  
  
  int HeapObject::Size() {
    return SizeFromMap(map());
  }
  
  
  double HeapNumber::value() const {
    return READ_DOUBLE_FIELD(this, kValueOffset);
  }
  
  
  void HeapNumber::set_value(double value) {
    WRITE_DOUBLE_FIELD(this, kValueOffset, value);
  }
  
  
  int HeapNumber::get_exponent() {
    return ((READ_INT_FIELD(this, kExponentOffset) & kExponentMask) >>
            kExponentShift) - kExponentBias;
  }
  
  
  int HeapNumber::get_sign() {
    return READ_INT_FIELD(this, kExponentOffset) & kSignMask;
  }
  
  
  bool Simd128Value::Equals(Simd128Value* that) {
    // TODO(bmeurer): This doesn't match the SIMD.js specification, but it seems
    // to be consistent with what the CompareICStub does, and what is tested in
    // the current SIMD.js testsuite.
    if (this == that) return true;
  #define SIMD128_VALUE(TYPE, Type, type, lane_count, lane_type) \
    if (this->Is##Type()) {                                      \
      if (!that->Is##Type()) return false;                       \
      return Type::cast(this)->Equals(Type::cast(that));         \
    }
    SIMD128_TYPES(SIMD128_VALUE)
  #undef SIMD128_VALUE
    return false;
  }
  
  
  // static
  bool Simd128Value::Equals(Handle<Simd128Value> one, Handle<Simd128Value> two) {
    return one->Equals(*two);
  }
  
  
  #define SIMD128_VALUE_EQUALS(TYPE, Type, type, lane_count, lane_type) \
    bool Type::Equals(Type* that) {                                     \
      for (int lane = 0; lane < lane_count; ++lane) {                   \
        if (this->get_lane(lane) != that->get_lane(lane)) return false; \
      }                                                                 \
      return true;                                                      \
    }
  SIMD128_TYPES(SIMD128_VALUE_EQUALS)
  #undef SIMD128_VALUE_EQUALS
  
  
  #if defined(V8_TARGET_LITTLE_ENDIAN)
  #define SIMD128_READ_LANE(lane_type, lane_count, field_type, field_size) \
    lane_type value =                                                      \
        READ_##field_type##_FIELD(this, kValueOffset + lane * field_size);
  #elif defined(V8_TARGET_BIG_ENDIAN)
  #define SIMD128_READ_LANE(lane_type, lane_count, field_type, field_size) \
    lane_type value = READ_##field_type##_FIELD(                           \
        this, kValueOffset + (lane_count - lane - 1) * field_size);
  #else
  #error Unknown byte ordering
  #endif
  
  #if defined(V8_TARGET_LITTLE_ENDIAN)
  #define SIMD128_WRITE_LANE(lane_count, field_type, field_size, value) \
    WRITE_##field_type##_FIELD(this, kValueOffset + lane * field_size, value);
  #elif defined(V8_TARGET_BIG_ENDIAN)
  #define SIMD128_WRITE_LANE(lane_count, field_type, field_size, value) \
    WRITE_##field_type##_FIELD(                                         \
        this, kValueOffset + (lane_count - lane - 1) * field_size, value);
  #else
  #error Unknown byte ordering
  #endif
  
  #define SIMD128_NUMERIC_LANE_FNS(type, lane_type, lane_count, field_type, \
                                   field_size)                              \
    lane_type type::get_lane(int lane) const {                              \
      DCHECK(lane < lane_count && lane >= 0);                               \
      SIMD128_READ_LANE(lane_type, lane_count, field_type, field_size)      \
      return value;                                                         \
    }                                                                       \
                                                                            \
    void type::set_lane(int lane, lane_type value) {                        \
      DCHECK(lane < lane_count && lane >= 0);                               \
      SIMD128_WRITE_LANE(lane_count, field_type, field_size, value)         \
    }
  
  SIMD128_NUMERIC_LANE_FNS(Float32x4, float, 4, FLOAT, kFloatSize)
  SIMD128_NUMERIC_LANE_FNS(Int32x4, int32_t, 4, INT32, kInt32Size)
  SIMD128_NUMERIC_LANE_FNS(Uint32x4, uint32_t, 4, UINT32, kInt32Size)
  SIMD128_NUMERIC_LANE_FNS(Int16x8, int16_t, 8, INT16, kShortSize)
  SIMD128_NUMERIC_LANE_FNS(Uint16x8, uint16_t, 8, UINT16, kShortSize)
  SIMD128_NUMERIC_LANE_FNS(Int8x16, int8_t, 16, INT8, kCharSize)
  SIMD128_NUMERIC_LANE_FNS(Uint8x16, uint8_t, 16, UINT8, kCharSize)
  #undef SIMD128_NUMERIC_LANE_FNS
  
  
  #define SIMD128_BOOLEAN_LANE_FNS(type, lane_type, lane_count, field_type, \
                                   field_size)                              \
    bool type::get_lane(int lane) const {                                   \
      DCHECK(lane < lane_count && lane >= 0);                               \
      SIMD128_READ_LANE(lane_type, lane_count, field_type, field_size)      \
      DCHECK(value == 0 || value == -1);                                    \
      return value != 0;                                                    \
    }                                                                       \
                                                                            \
    void type::set_lane(int lane, bool value) {                             \
      DCHECK(lane < lane_count && lane >= 0);                               \
      int32_t int_val = value ? -1 : 0;                                     \
      SIMD128_WRITE_LANE(lane_count, field_type, field_size, int_val)       \
    }
  
  SIMD128_BOOLEAN_LANE_FNS(Bool32x4, int32_t, 4, INT32, kInt32Size)
  SIMD128_BOOLEAN_LANE_FNS(Bool16x8, int16_t, 8, INT16, kShortSize)
  SIMD128_BOOLEAN_LANE_FNS(Bool8x16, int8_t, 16, INT8, kCharSize)
  #undef SIMD128_BOOLEAN_LANE_FNS
  
  #undef SIMD128_READ_LANE
  #undef SIMD128_WRITE_LANE
  
  
  ACCESSORS(JSReceiver, properties, FixedArray, kPropertiesOffset)
  
  
  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;
  }
  
  
  FixedArrayBase* JSObject::elements() const {
    Object* array = READ_FIELD(this, kElementsOffset);
    return static_cast<FixedArrayBase*>(array);
  }
  
  
  void AllocationSite::Initialize() {
    set_transition_info(Smi::FromInt(0));
    SetElementsKind(GetInitialFastElementsKind());
    set_nested_site(Smi::FromInt(0));
    set_pretenure_data(0);
    set_pretenure_create_count(0);
    set_dependent_code(DependentCode::cast(GetHeap()->empty_fixed_array()),
                       SKIP_WRITE_BARRIER);
  }
  
  
  bool AllocationSite::IsZombie() { return pretenure_decision() == kZombie; }
  
  
  bool AllocationSite::IsMaybeTenure() {
    return pretenure_decision() == kMaybeTenure;
  }
  
  
  bool AllocationSite::PretenuringDecisionMade() {
    return pretenure_decision() != kUndecided;
  }
  
  
  void AllocationSite::MarkZombie() {
    DCHECK(!IsZombie());
    Initialize();
    set_pretenure_decision(kZombie);
  }
  
  
  ElementsKind AllocationSite::GetElementsKind() {
    DCHECK(!SitePointsToLiteral());
    int value = Smi::cast(transition_info())->value();
    return ElementsKindBits::decode(value);
  }
  
  
  void AllocationSite::SetElementsKind(ElementsKind kind) {
    int value = Smi::cast(transition_info())->value();
    set_transition_info(Smi::FromInt(ElementsKindBits::update(value, kind)),
                        SKIP_WRITE_BARRIER);
  }
  
  
  bool AllocationSite::CanInlineCall() {
    int value = Smi::cast(transition_info())->value();
    return DoNotInlineBit::decode(value) == 0;
  }
  
  
  void AllocationSite::SetDoNotInlineCall() {
    int value = Smi::cast(transition_info())->value();
    set_transition_info(Smi::FromInt(DoNotInlineBit::update(value, true)),
                        SKIP_WRITE_BARRIER);
  }
  
  
  bool AllocationSite::SitePointsToLiteral() {
    // If transition_info is a smi, then it represents an ElementsKind
    // for a constructed array. Otherwise, it must be a boilerplate
    // for an object or array literal.
    return transition_info()->IsJSArray() || transition_info()->IsJSObject();
  }
  
  
  // Heuristic: We only need to create allocation site info if the boilerplate
  // elements kind is the initial elements kind.
  AllocationSiteMode AllocationSite::GetMode(
      ElementsKind boilerplate_elements_kind) {
    if (IsFastSmiElementsKind(boilerplate_elements_kind)) {
      return TRACK_ALLOCATION_SITE;
    }
  
    return DONT_TRACK_ALLOCATION_SITE;
  }
  
  
  AllocationSiteMode AllocationSite::GetMode(ElementsKind from,
                                             ElementsKind to) {
    if (IsFastSmiElementsKind(from) &&
        IsMoreGeneralElementsKindTransition(from, to)) {
      return TRACK_ALLOCATION_SITE;
    }
  
    return DONT_TRACK_ALLOCATION_SITE;
  }
  
  
  inline bool AllocationSite::CanTrack(InstanceType type) {
    if (FLAG_allocation_site_pretenuring) {
      return type == JS_ARRAY_TYPE ||
          type == JS_OBJECT_TYPE ||
          type < FIRST_NONSTRING_TYPE;
    }
    return type == JS_ARRAY_TYPE;
  }
  
  
  AllocationSite::PretenureDecision AllocationSite::pretenure_decision() {
    int value = pretenure_data();
    return PretenureDecisionBits::decode(value);
  }
  
  
  void AllocationSite::set_pretenure_decision(PretenureDecision decision) {
    int value = pretenure_data();
    set_pretenure_data(PretenureDecisionBits::update(value, decision));
  }
  
  
  bool AllocationSite::deopt_dependent_code() {
    int value = pretenure_data();
    return DeoptDependentCodeBit::decode(value);
  }
  
  
  void AllocationSite::set_deopt_dependent_code(bool deopt) {
    int value = pretenure_data();
    set_pretenure_data(DeoptDependentCodeBit::update(value, deopt));
  }
  
  
  int AllocationSite::memento_found_count() {
    int value = pretenure_data();
    return MementoFoundCountBits::decode(value);
  }
  
  
  inline void AllocationSite::set_memento_found_count(int count) {
    int value = pretenure_data();
    // Verify that we can count more mementos than we can possibly find in one
    // new space collection.
    DCHECK((GetHeap()->MaxSemiSpaceSize() /
            (Heap::kMinObjectSizeInWords * kPointerSize +
             AllocationMemento::kSize)) < MementoFoundCountBits::kMax);
    DCHECK(count < MementoFoundCountBits::kMax);
    set_pretenure_data(MementoFoundCountBits::update(value, count));
  }
  
  
  int AllocationSite::memento_create_count() { return pretenure_create_count(); }
  
  
  void AllocationSite::set_memento_create_count(int count) {
    set_pretenure_create_count(count);
  }
  
  
  bool AllocationSite::IncrementMementoFoundCount(int increment) {
    if (IsZombie()) return false;
  
    int value = memento_found_count();
    set_memento_found_count(value + increment);
    return memento_found_count() >= kPretenureMinimumCreated;
  }
  
  
  inline void AllocationSite::IncrementMementoCreateCount() {
    DCHECK(FLAG_allocation_site_pretenuring);
    int value = memento_create_count();
    set_memento_create_count(value + 1);
  }
  
  
  inline bool AllocationSite::MakePretenureDecision(
      PretenureDecision current_decision,
      double ratio,
      bool maximum_size_scavenge) {
    // Here we just allow state transitions from undecided or maybe tenure
    // to don't tenure, maybe tenure, or tenure.
    if ((current_decision == kUndecided || current_decision == kMaybeTenure)) {
      if (ratio >= kPretenureRatio) {
        // We just transition into tenure state when the semi-space was at
        // maximum capacity.
        if (maximum_size_scavenge) {
          set_deopt_dependent_code(true);
          set_pretenure_decision(kTenure);
          // Currently we just need to deopt when we make a state transition to
          // tenure.
          return true;
        }
        set_pretenure_decision(kMaybeTenure);
      } else {
        set_pretenure_decision(kDontTenure);
      }
    }
    return false;
  }
  
  
  inline bool AllocationSite::DigestPretenuringFeedback(
      bool maximum_size_scavenge) {
    bool deopt = false;
    int create_count = memento_create_count();
    int found_count = memento_found_count();
    bool minimum_mementos_created = create_count >= kPretenureMinimumCreated;
    double ratio =
        minimum_mementos_created || FLAG_trace_pretenuring_statistics ?
            static_cast<double>(found_count) / create_count : 0.0;
    PretenureDecision current_decision = pretenure_decision();
  
    if (minimum_mementos_created) {
      deopt = MakePretenureDecision(
          current_decision, ratio, maximum_size_scavenge);
    }
  
    if (FLAG_trace_pretenuring_statistics) {
      PrintIsolate(GetIsolate(),
                   "pretenuring: AllocationSite(%p): (created, found, ratio) "
                   "(%d, %d, %f) %s => %s\n",
                   this, create_count, found_count, ratio,
                   PretenureDecisionName(current_decision),
                   PretenureDecisionName(pretenure_decision()));
    }
  
    // Clear feedback calculation fields until the next gc.
    set_memento_found_count(0);
    set_memento_create_count(0);
    return deopt;
  }
  
  
  bool AllocationMemento::IsValid() {
    return allocation_site()->IsAllocationSite() &&
           !AllocationSite::cast(allocation_site())->IsZombie();
  }
  
  
  AllocationSite* AllocationMemento::GetAllocationSite() {
    DCHECK(IsValid());
    return AllocationSite::cast(allocation_site());
  }
  
  Address AllocationMemento::GetAllocationSiteUnchecked() {
    return reinterpret_cast<Address>(allocation_site());
  }
  
  void JSObject::EnsureCanContainHeapObjectElements(Handle<JSObject> object) {
    JSObject::ValidateElements(object);
    ElementsKind elements_kind = object->map()->elements_kind();
    if (!IsFastObjectElementsKind(elements_kind)) {
      if (IsFastHoleyElementsKind(elements_kind)) {
        TransitionElementsKind(object, FAST_HOLEY_ELEMENTS);
      } else {
        TransitionElementsKind(object, FAST_ELEMENTS);
      }
    }
  }
  
  
  void JSObject::EnsureCanContainElements(Handle<JSObject> object,
                                          Object** objects,
                                          uint32_t count,
                                          EnsureElementsMode mode) {
    ElementsKind current_kind = object->map()->elements_kind();
    ElementsKind target_kind = current_kind;
    {
      DisallowHeapAllocation no_allocation;
      DCHECK(mode != ALLOW_COPIED_DOUBLE_ELEMENTS);
      bool is_holey = IsFastHoleyElementsKind(current_kind);
      if (current_kind == FAST_HOLEY_ELEMENTS) return;
      Heap* heap = object->GetHeap();
      Object* the_hole = heap->the_hole_value();
      for (uint32_t i = 0; i < count; ++i) {
        Object* current = *objects++;
        if (current == the_hole) {
          is_holey = true;
          target_kind = GetHoleyElementsKind(target_kind);
        } else if (!current->IsSmi()) {
          if (mode == ALLOW_CONVERTED_DOUBLE_ELEMENTS && current->IsNumber()) {
            if (IsFastSmiElementsKind(target_kind)) {
              if (is_holey) {
                target_kind = FAST_HOLEY_DOUBLE_ELEMENTS;
              } else {
                target_kind = FAST_DOUBLE_ELEMENTS;
              }
            }
          } else if (is_holey) {
            target_kind = FAST_HOLEY_ELEMENTS;
            break;
          } else {
            target_kind = FAST_ELEMENTS;
          }
        }
      }
    }
    if (target_kind != current_kind) {
      TransitionElementsKind(object, target_kind);
    }
  }
  
  
  void JSObject::EnsureCanContainElements(Handle<JSObject> object,
                                          Handle<FixedArrayBase> elements,
                                          uint32_t length,
                                          EnsureElementsMode mode) {
    Heap* heap = object->GetHeap();
    if (elements->map() != heap->fixed_double_array_map()) {
      DCHECK(elements->map() == heap->fixed_array_map() ||
             elements->map() == heap->fixed_cow_array_map());
      if (mode == ALLOW_COPIED_DOUBLE_ELEMENTS) {
        mode = DONT_ALLOW_DOUBLE_ELEMENTS;
      }
      Object** objects =
          Handle<FixedArray>::cast(elements)->GetFirstElementAddress();
      EnsureCanContainElements(object, objects, length, mode);
      return;
    }
  
    DCHECK(mode == ALLOW_COPIED_DOUBLE_ELEMENTS);
    if (object->GetElementsKind() == FAST_HOLEY_SMI_ELEMENTS) {
      TransitionElementsKind(object, FAST_HOLEY_DOUBLE_ELEMENTS);
    } else if (object->GetElementsKind() == FAST_SMI_ELEMENTS) {
      Handle<FixedDoubleArray> double_array =
          Handle<FixedDoubleArray>::cast(elements);
      for (uint32_t i = 0; i < length; ++i) {
        if (double_array->is_the_hole(i)) {
          TransitionElementsKind(object, FAST_HOLEY_DOUBLE_ELEMENTS);
          return;
        }
      }
      TransitionElementsKind(object, FAST_DOUBLE_ELEMENTS);
    }
  }
  
  
  void JSObject::SetMapAndElements(Handle<JSObject> object,
                                   Handle<Map> new_map,
                                   Handle<FixedArrayBase> value) {
    JSObject::MigrateToMap(object, new_map);
    DCHECK((object->map()->has_fast_smi_or_object_elements() ||
            (*value == object->GetHeap()->empty_fixed_array()) ||
            object->map()->has_fast_string_wrapper_elements()) ==
           (value->map() == object->GetHeap()->fixed_array_map() ||
            value->map() == object->GetHeap()->fixed_cow_array_map()));
    DCHECK((*value == object->GetHeap()->empty_fixed_array()) ||
           (object->map()->has_fast_double_elements() ==
            value->IsFixedDoubleArray()));
    object->set_elements(*value);
  }
  
  
  void JSObject::set_elements(FixedArrayBase* value, WriteBarrierMode mode) {
    WRITE_FIELD(this, kElementsOffset, value);
    CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kElementsOffset, value, mode);
  }
  
  
  void JSObject::initialize_elements() {
    FixedArrayBase* elements = map()->GetInitialElements();
    WRITE_FIELD(this, kElementsOffset, elements);
  }
  
  
  InterceptorInfo* JSObject::GetIndexedInterceptor() {
    return map()->GetIndexedInterceptor();
  }
  
  InterceptorInfo* JSObject::GetNamedInterceptor() {
    return map()->GetNamedInterceptor();
  }
  
  InterceptorInfo* Map::GetNamedInterceptor() {
    DCHECK(has_named_interceptor());
    JSFunction* constructor = JSFunction::cast(GetConstructor());
    DCHECK(constructor->shared()->IsApiFunction());
    return InterceptorInfo::cast(
        constructor->shared()->get_api_func_data()->named_property_handler());
  }
  
  InterceptorInfo* Map::GetIndexedInterceptor() {
    DCHECK(has_indexed_interceptor());
    JSFunction* constructor = JSFunction::cast(GetConstructor());
    DCHECK(constructor->shared()->IsApiFunction());
    return InterceptorInfo::cast(
        constructor->shared()->get_api_func_data()->indexed_property_handler());
  }
  
  
  ACCESSORS(Oddball, to_string, String, kToStringOffset)
  ACCESSORS(Oddball, to_number, Object, kToNumberOffset)
  ACCESSORS(Oddball, to_boolean, Oddball, kToBooleanOffset)
  ACCESSORS(Oddball, type_of, String, kTypeOfOffset)
  
  
  byte Oddball::kind() const {
    return Smi::cast(READ_FIELD(this, kKindOffset))->value();
  }
  
  
  void Oddball::set_kind(byte value) {
    WRITE_FIELD(this, kKindOffset, Smi::FromInt(value));
  }
  
  
  // static
  Handle<Object> Oddball::ToNumber(Handle<Oddball> input) {
    return handle(input->to_number(), input->GetIsolate());
  }
  
  
  ACCESSORS(Cell, value, Object, kValueOffset)
  ACCESSORS(PropertyCell, dependent_code, DependentCode, kDependentCodeOffset)
  ACCESSORS(PropertyCell, property_details_raw, Object, kDetailsOffset)
  ACCESSORS(PropertyCell, value, Object, kValueOffset)
  
  
  PropertyDetails PropertyCell::property_details() {
    return PropertyDetails(Smi::cast(property_details_raw()));
  }
  
  
  void PropertyCell::set_property_details(PropertyDetails details) {
    set_property_details_raw(details.AsSmi());
  }
  
  
  Object* WeakCell::value() const { return READ_FIELD(this, kValueOffset); }
  
  
  void WeakCell::clear() {
    // Either the garbage collector is clearing the cell or we are simply
    // initializing the root empty weak cell.
    DCHECK(GetHeap()->gc_state() == Heap::MARK_COMPACT ||
           this == GetHeap()->empty_weak_cell());
    WRITE_FIELD(this, kValueOffset, Smi::FromInt(0));
  }
  
  
  void WeakCell::initialize(HeapObject* val) {
    WRITE_FIELD(this, kValueOffset, val);
    // We just have to execute the generational barrier here because we never
    // mark through a weak cell and collect evacuation candidates when we process
    // all weak cells.
    WriteBarrierMode mode =
        Page::FromAddress(this->address())->IsFlagSet(Page::BLACK_PAGE)
            ? UPDATE_WRITE_BARRIER
            : UPDATE_WEAK_WRITE_BARRIER;
    CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kValueOffset, val, mode);
  }
  
  
  bool WeakCell::cleared() const { return value() == Smi::FromInt(0); }
  
  
  Object* WeakCell::next() const { return READ_FIELD(this, kNextOffset); }
  
  
  void WeakCell::set_next(Object* val, WriteBarrierMode mode) {
    WRITE_FIELD(this, kNextOffset, val);
    if (mode == UPDATE_WRITE_BARRIER) {
      WRITE_BARRIER(GetHeap(), this, kNextOffset, val);
    }
  }
  
  
  void WeakCell::clear_next(Object* the_hole_value) {
    DCHECK_EQ(GetHeap()->the_hole_value(), the_hole_value);
    set_next(the_hole_value, SKIP_WRITE_BARRIER);
  }
  
  
  bool WeakCell::next_cleared() { return next()->IsTheHole(); }
  
  
  int JSObject::GetHeaderSize() { return GetHeaderSize(map()->instance_type()); }
  
  
  int JSObject::GetHeaderSize(InstanceType type) {
    // Check for the most common kind of JavaScript object before
    // falling into the generic switch. This speeds up the internal
    // field operations considerably on average.
    if (type == JS_OBJECT_TYPE) return JSObject::kHeaderSize;
    switch (type) {
      case JS_SPECIAL_API_OBJECT_TYPE:
        return JSObject::kHeaderSize;
      case JS_GENERATOR_OBJECT_TYPE:
        return JSGeneratorObject::kSize;
      case JS_MODULE_TYPE:
        return JSModule::kSize;
      case JS_GLOBAL_PROXY_TYPE:
        return JSGlobalProxy::kSize;
      case JS_GLOBAL_OBJECT_TYPE:
        return JSGlobalObject::kSize;
      case JS_BOUND_FUNCTION_TYPE:
        return JSBoundFunction::kSize;
      case JS_FUNCTION_TYPE:
        return JSFunction::kSize;
      case JS_VALUE_TYPE:
        return JSValue::kSize;
      case JS_DATE_TYPE:
        return JSDate::kSize;
      case JS_ARRAY_TYPE:
        return JSArray::kSize;
      case JS_ARRAY_BUFFER_TYPE:
        return JSArrayBuffer::kSize;
      case JS_TYPED_ARRAY_TYPE:
        return JSTypedArray::kSize;
      case JS_DATA_VIEW_TYPE:
        return JSDataView::kSize;
      case JS_SET_TYPE:
        return JSSet::kSize;
      case JS_MAP_TYPE:
        return JSMap::kSize;
      case JS_SET_ITERATOR_TYPE:
        return JSSetIterator::kSize;
      case JS_MAP_ITERATOR_TYPE:
        return JSMapIterator::kSize;
      case JS_WEAK_MAP_TYPE:
        return JSWeakMap::kSize;
      case JS_WEAK_SET_TYPE:
        return JSWeakSet::kSize;
      case JS_PROMISE_TYPE:
        return JSObject::kHeaderSize;
      case JS_REGEXP_TYPE:
        return JSRegExp::kSize;
      case JS_CONTEXT_EXTENSION_OBJECT_TYPE:
        return JSObject::kHeaderSize;
      case JS_MESSAGE_OBJECT_TYPE:
        return JSMessageObject::kSize;
      default:
        UNREACHABLE();
        return 0;
    }
  }
  
  
  int JSObject::GetInternalFieldCount(Map* map) {
    int instance_size = map->instance_size();
    if (instance_size == kVariableSizeSentinel) return 0;
    InstanceType instance_type = map->instance_type();
    return ((instance_size - GetHeaderSize(instance_type)) >> kPointerSizeLog2) -
           map->GetInObjectProperties();
  }
  
  
  int JSObject::GetInternalFieldCount() { return GetInternalFieldCount(map()); }
  
  
  int JSObject::GetInternalFieldOffset(int index) {
    DCHECK(index < GetInternalFieldCount() && index >= 0);
    return GetHeaderSize() + (kPointerSize * index);
  }
  
  
  Object* JSObject::GetInternalField(int index) {
    DCHECK(index < GetInternalFieldCount() && index >= 0);
    // Internal objects do follow immediately after the header, whereas in-object
    // properties are at the end of the object. Therefore there is no need
    // to adjust the index here.
    return READ_FIELD(this, GetHeaderSize() + (kPointerSize * index));
  }
  
  
  void JSObject::SetInternalField(int index, Object* value) {
    DCHECK(index < GetInternalFieldCount() && index >= 0);
    // Internal objects do follow immediately after the header, whereas in-object
    // properties are at the end of the object. Therefore there is no need
    // to adjust the index here.
    int offset = GetHeaderSize() + (kPointerSize * index);
    WRITE_FIELD(this, offset, value);
    WRITE_BARRIER(GetHeap(), this, offset, value);
  }
  
  
  void JSObject::SetInternalField(int index, Smi* value) {
    DCHECK(index < GetInternalFieldCount() && index >= 0);
    // Internal objects do follow immediately after the header, whereas in-object
    // properties are at the end of the object. Therefore there is no need
    // to adjust the index here.
    int offset = GetHeaderSize() + (kPointerSize * index);
    WRITE_FIELD(this, offset, value);
  }
  
  
  bool JSObject::IsUnboxedDoubleField(FieldIndex index) {
    if (!FLAG_unbox_double_fields) return false;
    return map()->IsUnboxedDoubleField(index);
  }
  
  
  bool Map::IsUnboxedDoubleField(FieldIndex index) {
    if (!FLAG_unbox_double_fields) return false;
    if (index.is_hidden_field() || !index.is_inobject()) return false;
    return !layout_descriptor()->IsTagged(index.property_index());
  }
  
  
  // Access fast-case object properties at index. The use of these routines
  // is needed to correctly distinguish between properties stored in-object and
  // properties stored in the properties array.
  Object* JSObject::RawFastPropertyAt(FieldIndex index) {
    DCHECK(!IsUnboxedDoubleField(index));
    if (index.is_inobject()) {
      return READ_FIELD(this, index.offset());
    } else {
      return properties()->get(index.outobject_array_index());
    }
  }
  
  
  double JSObject::RawFastDoublePropertyAt(FieldIndex index) {
    DCHECK(IsUnboxedDoubleField(index));
    return READ_DOUBLE_FIELD(this, index.offset());
  }
  
  
  void JSObject::RawFastPropertyAtPut(FieldIndex index, Object* value) {
    if (index.is_inobject()) {
      int offset = index.offset();
      WRITE_FIELD(this, offset, value);
      WRITE_BARRIER(GetHeap(), this, offset, value);
    } else {
      properties()->set(index.outobject_array_index(), value);
    }
  }
  
  
  void JSObject::RawFastDoublePropertyAtPut(FieldIndex index, double value) {
    WRITE_DOUBLE_FIELD(this, index.offset(), value);
  }
  
  
  void JSObject::FastPropertyAtPut(FieldIndex index, Object* value) {
    if (IsUnboxedDoubleField(index)) {
      DCHECK(value->IsMutableHeapNumber());
      RawFastDoublePropertyAtPut(index, HeapNumber::cast(value)->value());
    } else {
      RawFastPropertyAtPut(index, value);
    }
  }
  
  void JSObject::WriteToField(int descriptor, PropertyDetails details,
                              Object* value) {
    DCHECK(details.type() == DATA);
    DisallowHeapAllocation no_gc;
    FieldIndex index = FieldIndex::ForDescriptor(map(), descriptor);
    if (details.representation().IsDouble()) {
      // Nothing more to be done.
      if (value->IsUninitialized()) return;
      if (IsUnboxedDoubleField(index)) {
        RawFastDoublePropertyAtPut(index, value->Number());
      } else {
        HeapNumber* box = HeapNumber::cast(RawFastPropertyAt(index));
        DCHECK(box->IsMutableHeapNumber());
        box->set_value(value->Number());
      }
    } else {
      RawFastPropertyAtPut(index, value);
    }
  }
  
  void JSObject::WriteToField(int descriptor, Object* value) {
    DescriptorArray* desc = map()->instance_descriptors();
    PropertyDetails details = desc->GetDetails(descriptor);
    WriteToField(descriptor, details, value);
  }
  
  int JSObject::GetInObjectPropertyOffset(int index) {
    return map()->GetInObjectPropertyOffset(index);
  }
  
  
  Object* JSObject::InObjectPropertyAt(int index) {
    int offset = GetInObjectPropertyOffset(index);
    return READ_FIELD(this, offset);
  }
  
  
  Object* JSObject::InObjectPropertyAtPut(int index,
                                          Object* value,
                                          WriteBarrierMode mode) {
    // Adjust for the number of properties stored in the object.
    int offset = GetInObjectPropertyOffset(index);
    WRITE_FIELD(this, offset, value);
    CONDITIONAL_WRITE_BARRIER(GetHeap(), this, offset, value, mode);
    return value;
  }
  
  
  void JSObject::InitializeBody(Map* map, int start_offset,
                                Object* pre_allocated_value,
                                Object* filler_value) {
    DCHECK(!filler_value->IsHeapObject() ||
           !GetHeap()->InNewSpace(filler_value));
    DCHECK(!pre_allocated_value->IsHeapObject() ||
           !GetHeap()->InNewSpace(pre_allocated_value));
    int size = map->instance_size();
    int offset = start_offset;
    if (filler_value != pre_allocated_value) {
      int end_of_pre_allocated_offset =
          size - (map->unused_property_fields() * kPointerSize);
      DCHECK_LE(kHeaderSize, end_of_pre_allocated_offset);
      while (offset < end_of_pre_allocated_offset) {
        WRITE_FIELD(this, offset, pre_allocated_value);
        offset += kPointerSize;
      }
    }
    while (offset < size) {
      WRITE_FIELD(this, offset, filler_value);
      offset += kPointerSize;
    }
  }
  
  
  bool Map::TooManyFastProperties(StoreFromKeyed store_mode) {
    if (unused_property_fields() != 0) return false;
    if (is_prototype_map()) return false;
    int minimum = store_mode == CERTAINLY_NOT_STORE_FROM_KEYED ? 128 : 12;
    int limit = Max(minimum, GetInObjectProperties());
    int external = NumberOfFields() - GetInObjectProperties();
    return external > limit;
  }
  
  
  void Struct::InitializeBody(int object_size) {
    Object* value = GetHeap()->undefined_value();
    for (int offset = kHeaderSize; offset < object_size; offset += kPointerSize) {
      WRITE_FIELD(this, offset, value);
    }
  }
  
  bool Object::ToArrayLength(uint32_t* index) { return Object::ToUint32(index); }
  
  
  bool Object::ToArrayIndex(uint32_t* index) {
    return Object::ToUint32(index) && *index != kMaxUInt32;
  }
  
  
  void Object::VerifyApiCallResultType() {
  #if DEBUG
    if (!(IsSmi() || IsString() || IsSymbol() || IsJSReceiver() ||
          IsHeapNumber() || IsSimd128Value() || IsUndefined() || IsTrue() ||
          IsFalse() || IsNull())) {
      FATAL("API call returned invalid object");
    }
  #endif  // DEBUG
  }
  
  
  Object* FixedArray::get(int index) const {
    SLOW_DCHECK(index >= 0 && index < this->length());
    return READ_FIELD(this, kHeaderSize + index * kPointerSize);
  }
  
  Handle<Object> FixedArray::get(FixedArray* array, int index, Isolate* isolate) {
    return handle(array->get(index), isolate);
  }
  
  
  bool FixedArray::is_the_hole(int index) {
    return get(index) == GetHeap()->the_hole_value();
  }
  
  
  void FixedArray::set(int index, Smi* value) {
    DCHECK(map() != GetHeap()->fixed_cow_array_map());
    DCHECK(index >= 0 && index < this->length());
    DCHECK(reinterpret_cast<Object*>(value)->IsSmi());
    int offset = kHeaderSize + index * kPointerSize;
    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;
    WRITE_FIELD(this, offset, value);
    WRITE_BARRIER(GetHeap(), this, offset, value);
  }
  
  
  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(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(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::FromInt(0));
  }
  
  
  int WeakFixedArray::Length() const {
    return FixedArray::cast(this)->length() - kFirstIndex;
  }
  
  
  int WeakFixedArray::last_used_index() const {
    return Smi::cast(FixedArray::cast(this)->get(kLastUsedIndexIndex))->value();
  }
  
  
  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_ != NULL) {
      // 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_ = NULL;
    }
    return NULL;
  }
  
  
  int ArrayList::Length() {
    if (FixedArray::cast(this)->length() == 0) return 0;
    return Smi::cast(FixedArray::cast(this)->get(kLengthIndex))->value();
  }
  
  
  void ArrayList::SetLength(int length) {
    return FixedArray::cast(this)->set(kLengthIndex, Smi::FromInt(length));
  }
  
  
  Object* ArrayList::Get(int index) {
    return FixedArray::cast(this)->get(kFirstIndex + index);
  }
  
  
  Object** ArrayList::Slot(int index) {
    return data_start() + kFirstIndex + index;
  }
  
  
  void ArrayList::Set(int index, Object* obj) {
    FixedArray::cast(this)->set(kFirstIndex + index, obj);
  }
  
  
  void ArrayList::Clear(int index, Object* undefined) {
    DCHECK(undefined->IsUndefined());
    FixedArray::cast(this)
        ->set(kFirstIndex + index, undefined, SKIP_WRITE_BARRIER);
  }
  
  
  WriteBarrierMode HeapObject::GetWriteBarrierMode(
      const DisallowHeapAllocation& promise) {
    Heap* heap = GetHeap();
    if (heap->incremental_marking()->IsMarking()) return UPDATE_WRITE_BARRIER;
    if (heap->InNewSpace(this)) return SKIP_WRITE_BARRIER;
    return UPDATE_WRITE_BARRIER;
  }
  
  
  AllocationAlignment HeapObject::RequiredAlignment() {
  #ifdef V8_HOST_ARCH_32_BIT
    if ((IsFixedFloat64Array() || IsFixedDoubleArray()) &&
        FixedArrayBase::cast(this)->length() != 0) {
      return kDoubleAligned;
    }
    if (IsHeapNumber()) return kDoubleUnaligned;
    if (IsSimd128Value()) return kSimd128Unaligned;
  #endif  // V8_HOST_ARCH_32_BIT
    return kWordAligned;
  }
  
  
  void FixedArray::set(int index,
                       Object* value,
                       WriteBarrierMode mode) {
    DCHECK(map() != GetHeap()->fixed_cow_array_map());
    DCHECK(index >= 0 && index < this->length());
    int offset = kHeaderSize + index * kPointerSize;
    WRITE_FIELD(this, offset, value);
    CONDITIONAL_WRITE_BARRIER(GetHeap(), this, offset, value, mode);
  }
  
  
  void FixedArray::NoWriteBarrierSet(FixedArray* array,
                                     int index,
                                     Object* value) {
    DCHECK(array->map() != array->GetHeap()->fixed_cow_array_map());
    DCHECK(index >= 0 && index < array->length());
    DCHECK(!array->GetHeap()->InNewSpace(value));
    WRITE_FIELD(array, kHeaderSize + index * kPointerSize, value);
  }
  
  
  void FixedArray::set_undefined(int index) {
    DCHECK(map() != GetHeap()->fixed_cow_array_map());
    DCHECK(index >= 0 && index < this->length());
    DCHECK(!GetHeap()->InNewSpace(GetHeap()->undefined_value()));
    WRITE_FIELD(this,
                kHeaderSize + index * kPointerSize,
                GetHeap()->undefined_value());
  }
  
  
  void FixedArray::set_null(int index) {
    DCHECK(index >= 0 && index < this->length());
    DCHECK(!GetHeap()->InNewSpace(GetHeap()->null_value()));
    WRITE_FIELD(this,
                kHeaderSize + index * kPointerSize,
                GetHeap()->null_value());
  }
  
  
  void FixedArray::set_the_hole(int index) {
    DCHECK(map() != GetHeap()->fixed_cow_array_map());
    DCHECK(index >= 0 && index < this->length());
    DCHECK(!GetHeap()->InNewSpace(GetHeap()->the_hole_value()));
    WRITE_FIELD(this,
                kHeaderSize + index * kPointerSize,
                GetHeap()->the_hole_value());
  }
  
  
  void FixedArray::FillWithHoles(int from, int to) {
    for (int i = from; i < to; i++) {
      set_the_hole(i);
    }
  }
  
  
  Object** FixedArray::data_start() {
    return HeapObject::RawField(this, kHeaderSize);
  }
  
  
  Object** FixedArray::RawFieldOfElementAt(int index) {
    return HeapObject::RawField(this, OffsetOfElementAt(index));
  }
  
  
  bool DescriptorArray::IsEmpty() {
    DCHECK(length() >= kFirstIndex ||
           this == GetHeap()->empty_descriptor_array());
    return length() < kFirstIndex;
  }
  
  
  int DescriptorArray::number_of_descriptors() {
    DCHECK(length() >= kFirstIndex || IsEmpty());
    int len = length();
    return len == 0 ? 0 : Smi::cast(get(kDescriptorLengthIndex))->value();
  }
  
  
  int DescriptorArray::number_of_descriptors_storage() {
    int len = length();
    return len == 0 ? 0 : (len - kFirstIndex) / kDescriptorSize;
  }
  
  
  int DescriptorArray::NumberOfSlackDescriptors() {
    return number_of_descriptors_storage() - number_of_descriptors();
  }
  
  
  void DescriptorArray::SetNumberOfDescriptors(int number_of_descriptors) {
    WRITE_FIELD(
        this, kDescriptorLengthOffset, Smi::FromInt(number_of_descriptors));
  }
  
  
  inline int DescriptorArray::number_of_entries() {
    return number_of_descriptors();
  }
  
  
  bool DescriptorArray::HasEnumCache() {
    return !IsEmpty() && !get(kEnumCacheIndex)->IsSmi();
  }
  
  
  void DescriptorArray::CopyEnumCacheFrom(DescriptorArray* array) {
    set(kEnumCacheIndex, array->get(kEnumCacheIndex));
  }
  
  
  FixedArray* DescriptorArray::GetEnumCache() {
    DCHECK(HasEnumCache());
    FixedArray* bridge = FixedArray::cast(get(kEnumCacheIndex));
    return FixedArray::cast(bridge->get(kEnumCacheBridgeCacheIndex));
  }
  
  
  bool DescriptorArray::HasEnumIndicesCache() {
    if (IsEmpty()) return false;
    Object* object = get(kEnumCacheIndex);
    if (object->IsSmi()) return false;
    FixedArray* bridge = FixedArray::cast(object);
    return !bridge->get(kEnumCacheBridgeIndicesCacheIndex)->IsSmi();
  }
  
  
  FixedArray* DescriptorArray::GetEnumIndicesCache() {
    DCHECK(HasEnumIndicesCache());
    FixedArray* bridge = FixedArray::cast(get(kEnumCacheIndex));
    return FixedArray::cast(bridge->get(kEnumCacheBridgeIndicesCacheIndex));
  }
  
  
  Object** DescriptorArray::GetEnumCacheSlot() {
    DCHECK(HasEnumCache());
    return HeapObject::RawField(reinterpret_cast<HeapObject*>(this),
                                kEnumCacheOffset);
  }
  
  // Perform a binary search in a fixed array.
  template <SearchMode search_mode, typename T>
  int BinarySearch(T* array, Name* name, int valid_entries,
                   int* out_insertion_index) {
    DCHECK(search_mode == ALL_ENTRIES || out_insertion_index == NULL);
    int low = 0;
    int high = array->number_of_entries() - 1;
    uint32_t hash = name->hash_field();
    int limit = high;
  
    DCHECK(low <= high);
  
    while (low != high) {
      int mid = low + (high - low) / 2;
      Name* mid_name = array->GetSortedKey(mid);
      uint32_t mid_hash = mid_name->hash_field();
  
      if (mid_hash >= hash) {
        high = mid;
      } else {
        low = mid + 1;
      }
    }
  
    for (; low <= limit; ++low) {
      int sort_index = array->GetSortedKeyIndex(low);
      Name* entry = array->GetKey(sort_index);
      uint32_t current_hash = entry->hash_field();
      if (current_hash != hash) {
        if (search_mode == ALL_ENTRIES && out_insertion_index != nullptr) {
          *out_insertion_index = sort_index + (current_hash > hash ? 0 : 1);
        }
        return T::kNotFound;
      }
      if (entry == name) {
        if (search_mode == ALL_ENTRIES || sort_index < valid_entries) {
          return sort_index;
        }
        return T::kNotFound;
      }
    }
  
    if (search_mode == ALL_ENTRIES && out_insertion_index != nullptr) {
      *out_insertion_index = limit + 1;
    }
    return T::kNotFound;
  }
  
  
  // Perform a linear search in this fixed array. len is the number of entry
  // indices that are valid.
  template <SearchMode search_mode, typename T>
  int LinearSearch(T* array, Name* name, int valid_entries,
                   int* out_insertion_index) {
    if (search_mode == ALL_ENTRIES && out_insertion_index != nullptr) {
      uint32_t hash = name->hash_field();
      int len = array->number_of_entries();
      for (int number = 0; number < len; number++) {
        int sorted_index = array->GetSortedKeyIndex(number);
        Name* entry = array->GetKey(sorted_index);
        uint32_t current_hash = entry->hash_field();
        if (current_hash > hash) {
          *out_insertion_index = sorted_index;
          return T::kNotFound;
        }
        if (entry == name) return sorted_index;
      }
      *out_insertion_index = len;
      return T::kNotFound;
    } else {
      DCHECK_LE(valid_entries, array->number_of_entries());
      DCHECK_NULL(out_insertion_index);  // Not supported here.
      for (int number = 0; number < valid_entries; number++) {
        if (array->GetKey(number) == name) return number;
      }
      return T::kNotFound;
    }
  }
  
  
  template <SearchMode search_mode, typename T>
  int Search(T* array, Name* name, int valid_entries, int* out_insertion_index) {
    SLOW_DCHECK(array->IsSortedNoDuplicates());
  
    if (valid_entries == 0) {
      if (search_mode == ALL_ENTRIES && out_insertion_index != nullptr) {
        *out_insertion_index = 0;
      }
      return T::kNotFound;
    }
  
    // Fast case: do linear search for small arrays.
    const int kMaxElementsForLinearSearch = 8;
    if (valid_entries <= kMaxElementsForLinearSearch) {
      return LinearSearch<search_mode>(array, name, valid_entries,
                                       out_insertion_index);
    }
  
    // Slow case: perform binary search.
    return BinarySearch<search_mode>(array, name, valid_entries,
                                     out_insertion_index);
  }
  
  
  int DescriptorArray::Search(Name* name, int valid_descriptors) {
    DCHECK(name->IsUniqueName());
    return internal::Search<VALID_ENTRIES>(this, name, valid_descriptors, NULL);
  }
  
  int DescriptorArray::SearchWithCache(Isolate* isolate, Name* name, Map* map) {
    DCHECK(name->IsUniqueName());
    int number_of_own_descriptors = map->NumberOfOwnDescriptors();
    if (number_of_own_descriptors == 0) return kNotFound;
  
    DescriptorLookupCache* cache = isolate->descriptor_lookup_cache();
    int number = cache->Lookup(map, name);
  
    if (number == DescriptorLookupCache::kAbsent) {
      number = Search(name, number_of_own_descriptors);
      cache->Update(map, name, number);
    }
  
    return number;
  }
  
  PropertyDetails Map::GetLastDescriptorDetails() {
    return instance_descriptors()->GetDetails(LastAdded());
  }
  
  
  int Map::LastAdded() {
    int number_of_own_descriptors = NumberOfOwnDescriptors();
    DCHECK(number_of_own_descriptors > 0);
    return number_of_own_descriptors - 1;
  }
  
  
  int Map::NumberOfOwnDescriptors() {
    return NumberOfOwnDescriptorsBits::decode(bit_field3());
  }
  
  
  void Map::SetNumberOfOwnDescriptors(int number) {
    DCHECK(number <= instance_descriptors()->number_of_descriptors());
    set_bit_field3(NumberOfOwnDescriptorsBits::update(bit_field3(), number));
  }
  
  
  int Map::EnumLength() { return EnumLengthBits::decode(bit_field3()); }
  
  
  void Map::SetEnumLength(int length) {
    if (length != kInvalidEnumCacheSentinel) {
      DCHECK(length >= 0);
      DCHECK(length == 0 || instance_descriptors()->HasEnumCache());
      DCHECK(length <= NumberOfOwnDescriptors());
    }
    set_bit_field3(EnumLengthBits::update(bit_field3(), length));
  }
  
  
  FixedArrayBase* Map::GetInitialElements() {
    if (has_fast_elements() || has_fast_string_wrapper_elements()) {
      DCHECK(!GetHeap()->InNewSpace(GetHeap()->empty_fixed_array()));
      return GetHeap()->empty_fixed_array();
    } else if (has_fixed_typed_array_elements()) {
      FixedTypedArrayBase* empty_array =
          GetHeap()->EmptyFixedTypedArrayForMap(this);
      DCHECK(!GetHeap()->InNewSpace(empty_array));
      return empty_array;
    } else {
      UNREACHABLE();
    }
    return NULL;
  }
  
  // static
  Handle<Map> Map::ReconfigureProperty(Handle<Map> map, int modify_index,
                                       PropertyKind new_kind,
                                       PropertyAttributes new_attributes,
                                       Representation new_representation,
                                       Handle<FieldType> new_field_type,
                                       StoreMode store_mode) {
    return Reconfigure(map, map->elements_kind(), modify_index, new_kind,
                       new_attributes, new_representation, new_field_type,
                       store_mode);
  }
  
  // static
  Handle<Map> Map::ReconfigureElementsKind(Handle<Map> map,
                                           ElementsKind new_elements_kind) {
    return Reconfigure(map, new_elements_kind, -1, kData, NONE,
                       Representation::None(), FieldType::None(map->GetIsolate()),
                       ALLOW_IN_DESCRIPTOR);
  }
  
  Object** DescriptorArray::GetKeySlot(int descriptor_number) {
    DCHECK(descriptor_number < number_of_descriptors());
    return RawFieldOfElementAt(ToKeyIndex(descriptor_number));
  }
  
  
  Object** DescriptorArray::GetDescriptorStartSlot(int descriptor_number) {
    return GetKeySlot(descriptor_number);
  }
  
  
  Object** DescriptorArray::GetDescriptorEndSlot(int descriptor_number) {
    return GetValueSlot(descriptor_number - 1) + 1;
  }
  
  
  Name* DescriptorArray::GetKey(int descriptor_number) {
    DCHECK(descriptor_number < number_of_descriptors());
    return Name::cast(get(ToKeyIndex(descriptor_number)));
  }
  
  
  int DescriptorArray::GetSortedKeyIndex(int descriptor_number) {
    return GetDetails(descriptor_number).pointer();
  }
  
  
  Name* DescriptorArray::GetSortedKey(int descriptor_number) {
    return GetKey(GetSortedKeyIndex(descriptor_number));
  }
  
  
  void DescriptorArray::SetSortedKey(int descriptor_index, int pointer) {
    PropertyDetails details = GetDetails(descriptor_index);
    set(ToDetailsIndex(descriptor_index), details.set_pointer(pointer).AsSmi());
  }
  
  
  void DescriptorArray::SetRepresentation(int descriptor_index,
                                          Representation representation) {
    DCHECK(!representation.IsNone());
    PropertyDetails details = GetDetails(descriptor_index);
    set(ToDetailsIndex(descriptor_index),
        details.CopyWithRepresentation(representation).AsSmi());
  }
  
  
  Object** DescriptorArray::GetValueSlot(int descriptor_number) {
    DCHECK(descriptor_number < number_of_descriptors());
    return RawFieldOfElementAt(ToValueIndex(descriptor_number));
  }
  
  
  int DescriptorArray::GetValueOffset(int descriptor_number) {
    return OffsetOfElementAt(ToValueIndex(descriptor_number));
  }
  
  
  Object* DescriptorArray::GetValue(int descriptor_number) {
    DCHECK(descriptor_number < number_of_descriptors());
    return get(ToValueIndex(descriptor_number));
  }
  
  
  void DescriptorArray::SetValue(int descriptor_index, Object* value) {
    set(ToValueIndex(descriptor_index), value);
  }
  
  
  PropertyDetails DescriptorArray::GetDetails(int descriptor_number) {
    DCHECK(descriptor_number < number_of_descriptors());
    Object* details = get(ToDetailsIndex(descriptor_number));
    return PropertyDetails(Smi::cast(details));
  }
  
  
  PropertyType DescriptorArray::GetType(int descriptor_number) {
    return GetDetails(descriptor_number).type();
  }
  
  
  int DescriptorArray::GetFieldIndex(int descriptor_number) {
    DCHECK(GetDetails(descriptor_number).location() == kField);
    return GetDetails(descriptor_number).field_index();
  }
  
  Object* DescriptorArray::GetConstant(int descriptor_number) {
    return GetValue(descriptor_number);
  }
  
  
  Object* DescriptorArray::GetCallbacksObject(int descriptor_number) {
    DCHECK(GetType(descriptor_number) == ACCESSOR_CONSTANT);
    return GetValue(descriptor_number);
  }
  
  
  AccessorDescriptor* DescriptorArray::GetCallbacks(int descriptor_number) {
    DCHECK(GetType(descriptor_number) == ACCESSOR_CONSTANT);
    Foreign* p = Foreign::cast(GetCallbacksObject(descriptor_number));
    return reinterpret_cast<AccessorDescriptor*>(p->foreign_address());
  }
  
  
  void DescriptorArray::Get(int descriptor_number, Descriptor* desc) {
    desc->Init(handle(GetKey(descriptor_number), GetIsolate()),
               handle(GetValue(descriptor_number), GetIsolate()),
               GetDetails(descriptor_number));
  }
  
  
  void DescriptorArray::SetDescriptor(int descriptor_number, Descriptor* desc) {
    // Range check.
    DCHECK(descriptor_number < number_of_descriptors());
    set(ToKeyIndex(descriptor_number), *desc->GetKey());
    set(ToValueIndex(descriptor_number), *desc->GetValue());
    set(ToDetailsIndex(descriptor_number), desc->GetDetails().AsSmi());
  }
  
  
  void DescriptorArray::Set(int descriptor_number, Descriptor* desc) {
    // Range check.
    DCHECK(descriptor_number < number_of_descriptors());
  
    set(ToKeyIndex(descriptor_number), *desc->GetKey());
    set(ToValueIndex(descriptor_number), *desc->GetValue());
    set(ToDetailsIndex(descriptor_number), desc->GetDetails().AsSmi());
  }
  
  
  void DescriptorArray::Append(Descriptor* desc) {
    DisallowHeapAllocation no_gc;
    int descriptor_number = number_of_descriptors();
    SetNumberOfDescriptors(descriptor_number + 1);
    Set(descriptor_number, desc);
  
    uint32_t hash = desc->GetKey()->Hash();
  
    int insertion;
  
    for (insertion = descriptor_number; insertion > 0; --insertion) {
      Name* key = GetSortedKey(insertion - 1);
      if (key->Hash() <= hash) break;
      SetSortedKey(insertion, GetSortedKeyIndex(insertion - 1));
    }
  
    SetSortedKey(insertion, descriptor_number);
  }
  
  
  void DescriptorArray::SwapSortedKeys(int first, int second) {
    int first_key = GetSortedKeyIndex(first);
    SetSortedKey(first, GetSortedKeyIndex(second));
    SetSortedKey(second, first_key);
  }
  
  
  PropertyType DescriptorArray::Entry::type() { return descs_->GetType(index_); }
  
  
  Object* DescriptorArray::Entry::GetCallbackObject() {
    return descs_->GetValue(index_);
  }
  
  
  int HashTableBase::NumberOfElements() {
    return Smi::cast(get(kNumberOfElementsIndex))->value();
  }
  
  
  int HashTableBase::NumberOfDeletedElements() {
    return Smi::cast(get(kNumberOfDeletedElementsIndex))->value();
  }
  
  
  int HashTableBase::Capacity() {
    return Smi::cast(get(kCapacityIndex))->value();
  }
  
  
  void HashTableBase::ElementAdded() {
    SetNumberOfElements(NumberOfElements() + 1);
  }
  
  
  void HashTableBase::ElementRemoved() {
    SetNumberOfElements(NumberOfElements() - 1);
    SetNumberOfDeletedElements(NumberOfDeletedElements() + 1);
  }
  
  
  void HashTableBase::ElementsRemoved(int n) {
    SetNumberOfElements(NumberOfElements() - n);
    SetNumberOfDeletedElements(NumberOfDeletedElements() + n);
  }
  
  
  // static
  int HashTableBase::ComputeCapacity(int at_least_space_for) {
    const int kMinCapacity = 4;
    int capacity = base::bits::RoundUpToPowerOfTwo32(at_least_space_for * 2);
    return Max(capacity, kMinCapacity);
  }
  
  bool HashTableBase::IsKey(Heap* heap, Object* k) {
    return k != heap->the_hole_value() && k != heap->undefined_value();
  }
  
  bool HashTableBase::IsKey(Object* k) {
    return !k->IsTheHole() && !k->IsUndefined();
  }
  
  
  void HashTableBase::SetNumberOfElements(int nof) {
    set(kNumberOfElementsIndex, Smi::FromInt(nof));
  }
  
  
  void HashTableBase::SetNumberOfDeletedElements(int nod) {
    set(kNumberOfDeletedElementsIndex, Smi::FromInt(nod));
  }
  
  
  template <typename Derived, typename Shape, typename Key>
  int HashTable<Derived, Shape, Key>::FindEntry(Key key) {
    return FindEntry(GetIsolate(), key);
  }
  
  
  template<typename Derived, typename Shape, typename Key>
  int HashTable<Derived, Shape, Key>::FindEntry(Isolate* isolate, Key key) {
    return FindEntry(isolate, key, HashTable::Hash(key));
  }
  
  
  // Find entry for key otherwise return kNotFound.
  template <typename Derived, typename Shape, typename Key>
  int HashTable<Derived, Shape, Key>::FindEntry(Isolate* isolate, Key key,
                                                int32_t hash) {
    uint32_t capacity = Capacity();
    uint32_t entry = FirstProbe(hash, capacity);
    uint32_t count = 1;
    // EnsureCapacity will guarantee the hash table is never full.
    while (true) {
      Object* element = KeyAt(entry);
      // Empty entry. Uses raw unchecked accessors because it is called by the
      // string table during bootstrapping.
      if (element == isolate->heap()->root(Heap::kUndefinedValueRootIndex)) break;
      if (element != isolate->heap()->root(Heap::kTheHoleValueRootIndex) &&
          Shape::IsMatch(key, element)) return entry;
      entry = NextProbe(entry, count++, capacity);
    }
    return kNotFound;
  }
  
  bool StringSetShape::IsMatch(String* key, Object* value) {
    return value->IsString() && key->Equals(String::cast(value));
  }
  
  uint32_t StringSetShape::Hash(String* key) { return key->Hash(); }
  
  uint32_t StringSetShape::HashForObject(String* key, Object* object) {
    return object->IsString() ? String::cast(object)->Hash() : 0;
  }
  
  bool SeededNumberDictionary::requires_slow_elements() {
    Object* max_index_object = get(kMaxNumberKeyIndex);
    if (!max_index_object->IsSmi()) return false;
    return 0 !=
        (Smi::cast(max_index_object)->value() & kRequiresSlowElementsMask);
  }
  
  
  uint32_t SeededNumberDictionary::max_number_key() {
    DCHECK(!requires_slow_elements());
    Object* max_index_object = get(kMaxNumberKeyIndex);
    if (!max_index_object->IsSmi()) return 0;
    uint32_t value = static_cast<uint32_t>(Smi::cast(max_index_object)->value());
    return value >> kRequiresSlowElementsTagSize;
  }
  
  
  void SeededNumberDictionary::set_requires_slow_elements() {
    set(kMaxNumberKeyIndex, Smi::FromInt(kRequiresSlowElementsMask));
  }
  
  
  // ------------------------------------
  // Cast operations
  
  CAST_ACCESSOR(AbstractCode)
  CAST_ACCESSOR(ArrayList)
  CAST_ACCESSOR(Bool16x8)
  CAST_ACCESSOR(Bool32x4)
  CAST_ACCESSOR(Bool8x16)
  CAST_ACCESSOR(ByteArray)
  CAST_ACCESSOR(BytecodeArray)
  CAST_ACCESSOR(Cell)
  CAST_ACCESSOR(Code)
  CAST_ACCESSOR(CodeCacheHashTable)
  CAST_ACCESSOR(CompilationCacheTable)
  CAST_ACCESSOR(ConsString)
  CAST_ACCESSOR(DeoptimizationInputData)
  CAST_ACCESSOR(DeoptimizationOutputData)
  CAST_ACCESSOR(DependentCode)
  CAST_ACCESSOR(DescriptorArray)
  CAST_ACCESSOR(ExternalOneByteString)
  CAST_ACCESSOR(ExternalString)
  CAST_ACCESSOR(ExternalTwoByteString)
  CAST_ACCESSOR(FixedArray)
  CAST_ACCESSOR(FixedArrayBase)
  CAST_ACCESSOR(FixedDoubleArray)
  CAST_ACCESSOR(FixedTypedArrayBase)
  CAST_ACCESSOR(Float32x4)
  CAST_ACCESSOR(Foreign)
  CAST_ACCESSOR(GlobalDictionary)
  CAST_ACCESSOR(HandlerTable)
  CAST_ACCESSOR(HeapObject)
  CAST_ACCESSOR(Int16x8)
  CAST_ACCESSOR(Int32x4)
  CAST_ACCESSOR(Int8x16)
  CAST_ACCESSOR(JSArray)
  CAST_ACCESSOR(JSArrayBuffer)
  CAST_ACCESSOR(JSArrayBufferView)
  CAST_ACCESSOR(JSBoundFunction)
  CAST_ACCESSOR(JSDataView)
  CAST_ACCESSOR(JSDate)
  CAST_ACCESSOR(JSFunction)
  CAST_ACCESSOR(JSGeneratorObject)
  CAST_ACCESSOR(JSGlobalObject)
  CAST_ACCESSOR(JSGlobalProxy)
  CAST_ACCESSOR(JSMap)
  CAST_ACCESSOR(JSMapIterator)
  CAST_ACCESSOR(JSMessageObject)
  CAST_ACCESSOR(JSModule)
  CAST_ACCESSOR(JSObject)
  CAST_ACCESSOR(JSProxy)
  CAST_ACCESSOR(JSReceiver)
  CAST_ACCESSOR(JSRegExp)
  CAST_ACCESSOR(JSSet)
  CAST_ACCESSOR(JSSetIterator)
  CAST_ACCESSOR(JSTypedArray)
  CAST_ACCESSOR(JSValue)
  CAST_ACCESSOR(JSWeakMap)
  CAST_ACCESSOR(JSWeakSet)
  CAST_ACCESSOR(LayoutDescriptor)
  CAST_ACCESSOR(Map)
  CAST_ACCESSOR(Name)
  CAST_ACCESSOR(NameDictionary)
  CAST_ACCESSOR(NormalizedMapCache)
  CAST_ACCESSOR(Object)
  CAST_ACCESSOR(ObjectHashTable)
  CAST_ACCESSOR(Oddball)
  CAST_ACCESSOR(OrderedHashMap)
  CAST_ACCESSOR(OrderedHashSet)
  CAST_ACCESSOR(PolymorphicCodeCacheHashTable)
  CAST_ACCESSOR(PropertyCell)
  CAST_ACCESSOR(ScopeInfo)
  CAST_ACCESSOR(SeededNumberDictionary)
  CAST_ACCESSOR(SeqOneByteString)
  CAST_ACCESSOR(SeqString)
  CAST_ACCESSOR(SeqTwoByteString)
  CAST_ACCESSOR(SharedFunctionInfo)
  CAST_ACCESSOR(Simd128Value)
  CAST_ACCESSOR(SlicedString)
  CAST_ACCESSOR(Smi)
  CAST_ACCESSOR(String)
  CAST_ACCESSOR(StringSet)
  CAST_ACCESSOR(StringTable)
  CAST_ACCESSOR(Struct)
  CAST_ACCESSOR(Symbol)
  CAST_ACCESSOR(Uint16x8)
  CAST_ACCESSOR(Uint32x4)
  CAST_ACCESSOR(Uint8x16)
  CAST_ACCESSOR(UnseededNumberDictionary)
  CAST_ACCESSOR(WeakCell)
  CAST_ACCESSOR(WeakFixedArray)
  CAST_ACCESSOR(WeakHashTable)
  
  
  // 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);
  }
  
  
  #define DEFINE_DEOPT_ELEMENT_ACCESSORS(name, type)       \
    type* DeoptimizationInputData::name() {                \
      return type::cast(get(k##name##Index));              \
    }                                                      \
    void DeoptimizationInputData::Set##name(type* value) { \
      set(k##name##Index, value);                          \
    }
  
  DEFINE_DEOPT_ELEMENT_ACCESSORS(TranslationByteArray, ByteArray)
  DEFINE_DEOPT_ELEMENT_ACCESSORS(InlinedFunctionCount, Smi)
  DEFINE_DEOPT_ELEMENT_ACCESSORS(LiteralArray, FixedArray)
  DEFINE_DEOPT_ELEMENT_ACCESSORS(OsrAstId, Smi)
  DEFINE_DEOPT_ELEMENT_ACCESSORS(OsrPcOffset, Smi)
  DEFINE_DEOPT_ELEMENT_ACCESSORS(OptimizationId, Smi)
  DEFINE_DEOPT_ELEMENT_ACCESSORS(SharedFunctionInfo, Object)
  DEFINE_DEOPT_ELEMENT_ACCESSORS(WeakCellCache, Object)
  
  #undef DEFINE_DEOPT_ELEMENT_ACCESSORS
  
  
  #define DEFINE_DEOPT_ENTRY_ACCESSORS(name, type)                \
    type* DeoptimizationInputData::name(int i) {                  \
      return type::cast(get(IndexForEntry(i) + k##name##Offset)); \
    }                                                             \
    void DeoptimizationInputData::Set##name(int i, type* value) { \
      set(IndexForEntry(i) + k##name##Offset, value);             \
    }
  
  DEFINE_DEOPT_ENTRY_ACCESSORS(AstIdRaw, Smi)
  DEFINE_DEOPT_ENTRY_ACCESSORS(TranslationIndex, Smi)
  DEFINE_DEOPT_ENTRY_ACCESSORS(ArgumentsStackHeight, Smi)
  DEFINE_DEOPT_ENTRY_ACCESSORS(Pc, Smi)
  
  #undef DEFINE_DEOPT_ENTRY_ACCESSORS
  
  
  BailoutId DeoptimizationInputData::AstId(int i) {
    return BailoutId(AstIdRaw(i)->value());
  }
  
  
  void DeoptimizationInputData::SetAstId(int i, BailoutId value) {
    SetAstIdRaw(i, Smi::FromInt(value.ToInt()));
  }
  
  
  int DeoptimizationInputData::DeoptCount() {
    return (length() - kFirstDeoptEntryIndex) / kDeoptEntrySize;
  }
  
  
  int DeoptimizationOutputData::DeoptPoints() { return length() / 2; }
  
  
  BailoutId DeoptimizationOutputData::AstId(int index) {
    return BailoutId(Smi::cast(get(index * 2))->value());
  }
  
  
  void DeoptimizationOutputData::SetAstId(int index, BailoutId id) {
    set(index * 2, Smi::FromInt(id.ToInt()));
  }
  
  
  Smi* DeoptimizationOutputData::PcAndState(int index) {
    return Smi::cast(get(1 + index * 2));
  }
  
  
  void DeoptimizationOutputData::SetPcAndState(int index, Smi* offset) {
    set(1 + index * 2, offset);
  }
  
  
  Object* LiteralsArray::get(int index) const { return FixedArray::get(index); }
  
  
  void LiteralsArray::set(int index, Object* value) {
    FixedArray::set(index, value);
  }
  
  
  void LiteralsArray::set(int index, Smi* value) {
    FixedArray::set(index, value);
  }
  
  
  void LiteralsArray::set(int index, Object* value, WriteBarrierMode mode) {
    FixedArray::set(index, value, mode);
  }
  
  
  LiteralsArray* LiteralsArray::cast(Object* object) {
    SLOW_DCHECK(object->IsLiteralsArray());
    return reinterpret_cast<LiteralsArray*>(object);
  }
  
  
  TypeFeedbackVector* LiteralsArray::feedback_vector() const {
    return TypeFeedbackVector::cast(get(kVectorIndex));
  }
  
  
  void LiteralsArray::set_feedback_vector(TypeFeedbackVector* vector) {
    set(kVectorIndex, vector);
  }
  
  
  Object* LiteralsArray::literal(int literal_index) const {
    return get(kFirstLiteralIndex + literal_index);
  }
  
  
  void LiteralsArray::set_literal(int literal_index, Object* literal) {
    set(kFirstLiteralIndex + literal_index, literal);
  }
  
  
  int LiteralsArray::literals_count() const {
    return length() - kFirstLiteralIndex;
  }
  
  int HandlerTable::GetRangeStart(int index) const {
    return Smi::cast(get(index * kRangeEntrySize + kRangeStartIndex))->value();
  }
  
  int HandlerTable::GetRangeEnd(int index) const {
    return Smi::cast(get(index * kRangeEntrySize + kRangeEndIndex))->value();
  }
  
  int HandlerTable::GetRangeHandler(int index) const {
    return HandlerOffsetField::decode(
        Smi::cast(get(index * kRangeEntrySize + kRangeHandlerIndex))->value());
  }
  
  int HandlerTable::GetRangeData(int index) const {
    return Smi::cast(get(index * kRangeEntrySize + kRangeDataIndex))->value();
  }
  
  HandlerTable::CatchPrediction HandlerTable::GetRangePrediction(
      int index) const {
    return HandlerPredictionField::decode(
        Smi::cast(get(index * kRangeEntrySize + kRangeHandlerIndex))->value());
  }
  
  void HandlerTable::SetRangeStart(int index, int value) {
    set(index * kRangeEntrySize + kRangeStartIndex, Smi::FromInt(value));
  }
  
  
  void HandlerTable::SetRangeEnd(int index, int value) {
    set(index * kRangeEntrySize + kRangeEndIndex, Smi::FromInt(value));
  }
  
  
  void HandlerTable::SetRangeHandler(int index, int offset,
                                     CatchPrediction prediction) {
    int value = HandlerOffsetField::encode(offset) |
                HandlerPredictionField::encode(prediction);
    set(index * kRangeEntrySize + kRangeHandlerIndex, Smi::FromInt(value));
  }
  
  void HandlerTable::SetRangeData(int index, int value) {
    set(index * kRangeEntrySize + kRangeDataIndex, Smi::FromInt(value));
  }
  
  
  void HandlerTable::SetReturnOffset(int index, int value) {
    set(index * kReturnEntrySize + kReturnOffsetIndex, Smi::FromInt(value));
  }
  
  
  void HandlerTable::SetReturnHandler(int index, int offset,
                                      CatchPrediction prediction) {
    int value = HandlerOffsetField::encode(offset) |
                HandlerPredictionField::encode(prediction);
    set(index * kReturnEntrySize + kReturnHandlerIndex, Smi::FromInt(value));
  }
  
  int HandlerTable::NumberOfRangeEntries() const {
    return length() / kRangeEntrySize;
  }
  
  #define MAKE_STRUCT_CAST(NAME, Name, name) CAST_ACCESSOR(Name)
    STRUCT_LIST(MAKE_STRUCT_CAST)
  #undef MAKE_STRUCT_CAST
  
  
  template <typename Derived, typename Shape, typename Key>
  HashTable<Derived, Shape, Key>*
  HashTable<Derived, Shape, Key>::cast(Object* obj) {
    SLOW_DCHECK(obj->IsHashTable());
    return reinterpret_cast<HashTable*>(obj);
  }
  
  
  template <typename Derived, typename Shape, typename Key>
  const HashTable<Derived, Shape, Key>*
  HashTable<Derived, Shape, Key>::cast(const Object* obj) {
    SLOW_DCHECK(obj->IsHashTable());
    return reinterpret_cast<const HashTable*>(obj);
  }
  
  
  SMI_ACCESSORS(FixedArrayBase, length, kLengthOffset)
  SYNCHRONIZED_SMI_ACCESSORS(FixedArrayBase, length, kLengthOffset)
  
  SMI_ACCESSORS(FreeSpace, size, kSizeOffset)
  NOBARRIER_SMI_ACCESSORS(FreeSpace, size, kSizeOffset)
  
  SMI_ACCESSORS(String, length, kLengthOffset)
  SYNCHRONIZED_SMI_ACCESSORS(String, length, kLengthOffset)
  
  
  int FreeSpace::Size() { return size(); }
  
  
  FreeSpace* FreeSpace::next() {
    DCHECK(map() == GetHeap()->root(Heap::kFreeSpaceMapRootIndex) ||
           (!GetHeap()->deserialization_complete() && map() == NULL));
    DCHECK_LE(kNextOffset + kPointerSize, nobarrier_size());
    return reinterpret_cast<FreeSpace*>(
        Memory::Address_at(address() + kNextOffset));
  }
  
  
  void FreeSpace::set_next(FreeSpace* next) {
    DCHECK(map() == GetHeap()->root(Heap::kFreeSpaceMapRootIndex) ||
           (!GetHeap()->deserialization_complete() && map() == NULL));
    DCHECK_LE(kNextOffset + kPointerSize, nobarrier_size());
    base::NoBarrier_Store(
        reinterpret_cast<base::AtomicWord*>(address() + kNextOffset),
        reinterpret_cast<base::AtomicWord>(next));
  }
  
  
  FreeSpace* FreeSpace::cast(HeapObject* o) {
    SLOW_DCHECK(!o->GetHeap()->deserialization_complete() || o->IsFreeSpace());
    return reinterpret_cast<FreeSpace*>(o);
  }
  
  
  uint32_t Name::hash_field() {
    return READ_UINT32_FIELD(this, kHashFieldOffset);
  }
  
  
  void Name::set_hash_field(uint32_t value) {
    WRITE_UINT32_FIELD(this, kHashFieldOffset, value);
  #if V8_HOST_ARCH_64_BIT
  #if V8_TARGET_LITTLE_ENDIAN
    WRITE_UINT32_FIELD(this, kHashFieldSlot + kIntSize, 0);
  #else
    WRITE_UINT32_FIELD(this, kHashFieldSlot, 0);
  #endif
  #endif
  }
  
  
  bool Name::Equals(Name* other) {
    if (other == this) return true;
    if ((this->IsInternalizedString() && other->IsInternalizedString()) ||
        this->IsSymbol() || other->IsSymbol()) {
      return false;
    }
    return String::cast(this)->SlowEquals(String::cast(other));
  }
  
  
  bool Name::Equals(Handle<Name> one, Handle<Name> two) {
    if (one.is_identical_to(two)) return true;
    if ((one->IsInternalizedString() && two->IsInternalizedString()) ||
        one->IsSymbol() || two->IsSymbol()) {
      return false;
    }
    return String::SlowEquals(Handle<String>::cast(one),
                              Handle<String>::cast(two));
  }
  
  
  ACCESSORS(Symbol, name, Object, kNameOffset)
  SMI_ACCESSORS(Symbol, flags, kFlagsOffset)
  BOOL_ACCESSORS(Symbol, flags, is_private, kPrivateBit)
  BOOL_ACCESSORS(Symbol, flags, is_well_known_symbol, kWellKnownSymbolBit)
  
  
  bool String::Equals(String* other) {
    if (other == this) return true;
    if (this->IsInternalizedString() && other->IsInternalizedString()) {
      return false;
    }
    return SlowEquals(other);
  }
  
  
  bool String::Equals(Handle<String> one, Handle<String> two) {
    if (one.is_identical_to(two)) return true;
    if (one->IsInternalizedString() && two->IsInternalizedString()) {
      return false;
    }
    return SlowEquals(one, two);
  }
  
  
  Handle<String> String::Flatten(Handle<String> string, PretenureFlag pretenure) {
    if (!string->IsConsString()) return string;
    Handle<ConsString> cons = Handle<ConsString>::cast(string);
    if (cons->IsFlat()) return handle(cons->first());
    return SlowFlatten(cons, pretenure);
  }
  
  
  uint16_t String::Get(int index) {
    DCHECK(index >= 0 && index < length());
    switch (StringShape(this).full_representation_tag()) {
      case kSeqStringTag | kOneByteStringTag:
        return SeqOneByteString::cast(this)->SeqOneByteStringGet(index);
      case kSeqStringTag | kTwoByteStringTag:
        return SeqTwoByteString::cast(this)->SeqTwoByteStringGet(index);
      case kConsStringTag | kOneByteStringTag:
      case kConsStringTag | kTwoByteStringTag:
        return ConsString::cast(this)->ConsStringGet(index);
      case kExternalStringTag | kOneByteStringTag:
        return ExternalOneByteString::cast(this)->ExternalOneByteStringGet(index);
      case kExternalStringTag | kTwoByteStringTag:
        return ExternalTwoByteString::cast(this)->ExternalTwoByteStringGet(index);
      case kSlicedStringTag | kOneByteStringTag:
      case kSlicedStringTag | kTwoByteStringTag:
        return SlicedString::cast(this)->SlicedStringGet(index);
      default:
        break;
    }
  
    UNREACHABLE();
    return 0;
  }
  
  
  void String::Set(int index, uint16_t value) {
    DCHECK(index >= 0 && index < length());
    DCHECK(StringShape(this).IsSequential());
  
    return this->IsOneByteRepresentation()
        ? SeqOneByteString::cast(this)->SeqOneByteStringSet(index, value)
        : SeqTwoByteString::cast(this)->SeqTwoByteStringSet(index, value);
  }
  
  
  bool String::IsFlat() {
    if (!StringShape(this).IsCons()) return true;
    return ConsString::cast(this)->second()->length() == 0;
  }
  
  
  String* String::GetUnderlying() {
    // Giving direct access to underlying string only makes sense if the
    // wrapping string is already flattened.
    DCHECK(this->IsFlat());
    DCHECK(StringShape(this).IsIndirect());
    STATIC_ASSERT(ConsString::kFirstOffset == SlicedString::kParentOffset);
    const int kUnderlyingOffset = SlicedString::kParentOffset;
    return String::cast(READ_FIELD(this, kUnderlyingOffset));
  }
  
  
  template<class Visitor>
  ConsString* String::VisitFlat(Visitor* visitor,
                                String* string,
                                const int offset) {
    int slice_offset = offset;
    const int length = string->length();
    DCHECK(offset <= length);
    while (true) {
      int32_t type = string->map()->instance_type();
      switch (type & (kStringRepresentationMask | kStringEncodingMask)) {
        case kSeqStringTag | kOneByteStringTag:
          visitor->VisitOneByteString(
              SeqOneByteString::cast(string)->GetChars() + slice_offset,
              length - offset);
          return NULL;
  
        case kSeqStringTag | kTwoByteStringTag:
          visitor->VisitTwoByteString(
              SeqTwoByteString::cast(string)->GetChars() + slice_offset,
              length - offset);
          return NULL;
  
        case kExternalStringTag | kOneByteStringTag:
          visitor->VisitOneByteString(
              ExternalOneByteString::cast(string)->GetChars() + slice_offset,
              length - offset);
          return NULL;
  
        case kExternalStringTag | kTwoByteStringTag:
          visitor->VisitTwoByteString(
              ExternalTwoByteString::cast(string)->GetChars() + slice_offset,
              length - offset);
          return NULL;
  
        case kSlicedStringTag | kOneByteStringTag:
        case kSlicedStringTag | kTwoByteStringTag: {
          SlicedString* slicedString = SlicedString::cast(string);
          slice_offset += slicedString->offset();
          string = slicedString->parent();
          continue;
        }
  
        case kConsStringTag | kOneByteStringTag:
        case kConsStringTag | kTwoByteStringTag:
          return ConsString::cast(string);
  
        default:
          UNREACHABLE();
          return NULL;
      }
    }
  }
  
  
  template <>
  inline Vector<const uint8_t> String::GetCharVector() {
    String::FlatContent flat = GetFlatContent();
    DCHECK(flat.IsOneByte());
    return flat.ToOneByteVector();
  }
  
  
  template <>
  inline Vector<const uc16> String::GetCharVector() {
    String::FlatContent flat = GetFlatContent();
    DCHECK(flat.IsTwoByte());
    return flat.ToUC16Vector();
  }
  
  
  uint16_t SeqOneByteString::SeqOneByteStringGet(int index) {
    DCHECK(index >= 0 && index < length());
    return READ_BYTE_FIELD(this, kHeaderSize + index * kCharSize);
  }
  
  
  void SeqOneByteString::SeqOneByteStringSet(int index, uint16_t value) {
    DCHECK(index >= 0 && index < length() && value <= kMaxOneByteCharCode);
    WRITE_BYTE_FIELD(this, kHeaderSize + index * kCharSize,
                     static_cast<byte>(value));
  }
  
  
  Address SeqOneByteString::GetCharsAddress() {
    return FIELD_ADDR(this, kHeaderSize);
  }
  
  
  uint8_t* SeqOneByteString::GetChars() {
    return reinterpret_cast<uint8_t*>(GetCharsAddress());
  }
  
  
  Address SeqTwoByteString::GetCharsAddress() {
    return FIELD_ADDR(this, kHeaderSize);
  }
  
  
  uc16* SeqTwoByteString::GetChars() {
    return reinterpret_cast<uc16*>(FIELD_ADDR(this, kHeaderSize));
  }
  
  
  uint16_t SeqTwoByteString::SeqTwoByteStringGet(int index) {
    DCHECK(index >= 0 && index < length());
    return READ_UINT16_FIELD(this, kHeaderSize + index * kShortSize);
  }
  
  
  void SeqTwoByteString::SeqTwoByteStringSet(int index, uint16_t value) {
    DCHECK(index >= 0 && index < length());
    WRITE_UINT16_FIELD(this, kHeaderSize + index * kShortSize, value);
  }
  
  
  int SeqTwoByteString::SeqTwoByteStringSize(InstanceType instance_type) {
    return SizeFor(length());
  }
  
  
  int SeqOneByteString::SeqOneByteStringSize(InstanceType instance_type) {
    return SizeFor(length());
  }
  
  
  String* SlicedString::parent() {
    return String::cast(READ_FIELD(this, kParentOffset));
  }
  
  
  void SlicedString::set_parent(String* parent, WriteBarrierMode mode) {
    DCHECK(parent->IsSeqString() || parent->IsExternalString());
    WRITE_FIELD(this, kParentOffset, parent);
    CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kParentOffset, parent, mode);
  }
  
  
  SMI_ACCESSORS(SlicedString, offset, kOffsetOffset)
  
  
  String* ConsString::first() {
    return String::cast(READ_FIELD(this, kFirstOffset));
  }
  
  
  Object* ConsString::unchecked_first() {
    return READ_FIELD(this, kFirstOffset);
  }
  
  
  void ConsString::set_first(String* value, WriteBarrierMode mode) {
    WRITE_FIELD(this, kFirstOffset, value);
    CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kFirstOffset, value, mode);
  }
  
  
  String* ConsString::second() {
    return String::cast(READ_FIELD(this, kSecondOffset));
  }
  
  
  Object* ConsString::unchecked_second() {
    return READ_FIELD(this, kSecondOffset);
  }
  
  
  void ConsString::set_second(String* value, WriteBarrierMode mode) {
    WRITE_FIELD(this, kSecondOffset, value);
    CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kSecondOffset, value, mode);
  }
  
  
  bool ExternalString::is_short() {
    InstanceType type = map()->instance_type();
    return (type & kShortExternalStringMask) == kShortExternalStringTag;
  }
  
  
  const ExternalOneByteString::Resource* ExternalOneByteString::resource() {
    return *reinterpret_cast<Resource**>(FIELD_ADDR(this, kResourceOffset));
  }
  
  
  void ExternalOneByteString::update_data_cache() {
    if (is_short()) return;
    const char** data_field =
        reinterpret_cast<const char**>(FIELD_ADDR(this, kResourceDataOffset));
    *data_field = resource()->data();
  }
  
  
  void ExternalOneByteString::set_resource(
      const ExternalOneByteString::Resource* resource) {
    DCHECK(IsAligned(reinterpret_cast<intptr_t>(resource), kPointerSize));
    *reinterpret_cast<const Resource**>(
        FIELD_ADDR(this, kResourceOffset)) = resource;
    if (resource != NULL) update_data_cache();
  }
  
  
  const uint8_t* ExternalOneByteString::GetChars() {
    return reinterpret_cast<const uint8_t*>(resource()->data());
  }
  
  
  uint16_t ExternalOneByteString::ExternalOneByteStringGet(int index) {
    DCHECK(index >= 0 && index < length());
    return GetChars()[index];
  }
  
  
  const ExternalTwoByteString::Resource* ExternalTwoByteString::resource() {
    return *reinterpret_cast<Resource**>(FIELD_ADDR(this, kResourceOffset));
  }
  
  
  void ExternalTwoByteString::update_data_cache() {
    if (is_short()) return;
    const uint16_t** data_field =
        reinterpret_cast<const uint16_t**>(FIELD_ADDR(this, kResourceDataOffset));
    *data_field = resource()->data();
  }
  
  
  void ExternalTwoByteString::set_resource(
      const ExternalTwoByteString::Resource* resource) {
    *reinterpret_cast<const Resource**>(
        FIELD_ADDR(this, kResourceOffset)) = resource;
    if (resource != NULL) update_data_cache();
  }
  
  
  const uint16_t* ExternalTwoByteString::GetChars() {
    return resource()->data();
  }
  
  
  uint16_t ExternalTwoByteString::ExternalTwoByteStringGet(int index) {
    DCHECK(index >= 0 && index < length());
    return GetChars()[index];
  }
  
  
  const uint16_t* ExternalTwoByteString::ExternalTwoByteStringGetData(
        unsigned start) {
    return GetChars() + start;
  }
  
  
  int ConsStringIterator::OffsetForDepth(int depth) { return depth & kDepthMask; }
  
  
  void ConsStringIterator::PushLeft(ConsString* string) {
    frames_[depth_++ & kDepthMask] = string;
  }
  
  
  void ConsStringIterator::PushRight(ConsString* string) {
    // Inplace update.
    frames_[(depth_-1) & kDepthMask] = string;
  }
  
  
  void ConsStringIterator::AdjustMaximumDepth() {
    if (depth_ > maximum_depth_) maximum_depth_ = depth_;
  }
  
  
  void ConsStringIterator::Pop() {
    DCHECK(depth_ > 0);
    DCHECK(depth_ <= maximum_depth_);
    depth_--;
  }
  
  
  uint16_t StringCharacterStream::GetNext() {
    DCHECK(buffer8_ != NULL && end_ != NULL);
    // Advance cursor if needed.
    if (buffer8_ == end_) HasMore();
    DCHECK(buffer8_ < end_);
    return is_one_byte_ ? *buffer8_++ : *buffer16_++;
  }
  
  
  StringCharacterStream::StringCharacterStream(String* string, int offset)
      : is_one_byte_(false) {
    Reset(string, offset);
  }
  
  
  void StringCharacterStream::Reset(String* string, int offset) {
    buffer8_ = NULL;
    end_ = NULL;
    ConsString* cons_string = String::VisitFlat(this, string, offset);
    iter_.Reset(cons_string, offset);
    if (cons_string != NULL) {
      string = iter_.Next(&offset);
      if (string != NULL) String::VisitFlat(this, string, offset);
    }
  }
  
  
  bool StringCharacterStream::HasMore() {
    if (buffer8_ != end_) return true;
    int offset;
    String* string = iter_.Next(&offset);
    DCHECK_EQ(offset, 0);
    if (string == NULL) return false;
    String::VisitFlat(this, string);
    DCHECK(buffer8_ != end_);
    return true;
  }
  
  
  void StringCharacterStream::VisitOneByteString(
      const uint8_t* chars, int length) {
    is_one_byte_ = true;
    buffer8_ = chars;
    end_ = chars + length;
  }
  
  
  void StringCharacterStream::VisitTwoByteString(
      const uint16_t* chars, int length) {
    is_one_byte_ = false;
    buffer16_ = chars;
    end_ = reinterpret_cast<const uint8_t*>(chars + length);
  }
  
  
  int ByteArray::Size() { return RoundUp(length() + kHeaderSize, kPointerSize); }
  
  
  byte ByteArray::get(int index) {
    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);
  }
  
  
  int ByteArray::get_int(int index) {
    DCHECK(index >= 0 && (index * kIntSize) < this->length());
    return READ_INT_FIELD(this, kHeaderSize + index * kIntSize);
  }
  
  
  ByteArray* ByteArray::FromDataStartAddress(Address address) {
    DCHECK_TAG_ALIGNED(address);
    return reinterpret_cast<ByteArray*>(address - kHeaderSize + kHeapObjectTag);
  }
  
  
  int ByteArray::ByteArraySize() { return SizeFor(this->length()); }
  
  
  Address ByteArray::GetDataStartAddress() {
    return reinterpret_cast<Address>(this) - kHeapObjectTag + kHeaderSize;
  }
  
  
  byte BytecodeArray::get(int index) {
    DCHECK(index >= 0 && index < this->length());
    return READ_BYTE_FIELD(this, kHeaderSize + index * kCharSize);
  }
  
  
  void BytecodeArray::set(int index, byte value) {
    DCHECK(index >= 0 && index < this->length());
    WRITE_BYTE_FIELD(this, kHeaderSize + index * kCharSize, value);
  }
  
  
  void BytecodeArray::set_frame_size(int frame_size) {
    DCHECK_GE(frame_size, 0);
    DCHECK(IsAligned(frame_size, static_cast<unsigned>(kPointerSize)));
    WRITE_INT_FIELD(this, kFrameSizeOffset, frame_size);
  }
  
  
  int BytecodeArray::frame_size() const {
    return READ_INT_FIELD(this, kFrameSizeOffset);
  }
  
  
  int BytecodeArray::register_count() const {
    return frame_size() / kPointerSize;
  }
  
  
  void BytecodeArray::set_parameter_count(int number_of_parameters) {
    DCHECK_GE(number_of_parameters, 0);
    // Parameter count is stored as the size on stack of the parameters to allow
    // it to be used directly by generated code.
    WRITE_INT_FIELD(this, kParameterSizeOffset,
                    (number_of_parameters << kPointerSizeLog2));
  }
  
  int BytecodeArray::interrupt_budget() const {
    return READ_INT_FIELD(this, kInterruptBudgetOffset);
  }
  
  void BytecodeArray::set_interrupt_budget(int interrupt_budget) {
    DCHECK_GE(interrupt_budget, 0);
    WRITE_INT_FIELD(this, kInterruptBudgetOffset, interrupt_budget);
  }
  
  int BytecodeArray::parameter_count() const {
    // Parameter count is stored as the size on stack of the parameters to allow
    // it to be used directly by generated code.
    return READ_INT_FIELD(this, kParameterSizeOffset) >> kPointerSizeLog2;
  }
  
  
  ACCESSORS(BytecodeArray, constant_pool, FixedArray, kConstantPoolOffset)
  ACCESSORS(BytecodeArray, handler_table, FixedArray, kHandlerTableOffset)
  ACCESSORS(BytecodeArray, source_position_table, ByteArray,
            kSourcePositionTableOffset)
  
  Address BytecodeArray::GetFirstBytecodeAddress() {
    return reinterpret_cast<Address>(this) - kHeapObjectTag + kHeaderSize;
  }
  
  
  int BytecodeArray::BytecodeArraySize() { return SizeFor(this->length()); }
  
  
  ACCESSORS(FixedTypedArrayBase, base_pointer, Object, kBasePointerOffset)
  
  
  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 0;
    }
    return element_size;
  }
  
  
  int FixedTypedArrayBase::DataSize(InstanceType type) {
    if (base_pointer() == Smi::FromInt(0)) return 0;
    return length() * ElementSize(type);
  }
  
  
  int FixedTypedArrayBase::DataSize() {
    return DataSize(map()->instance_type());
  }
  
  
  int FixedTypedArrayBase::size() {
    return OBJECT_POINTER_ALIGN(kDataOffset + DataSize());
  }
  
  
  int FixedTypedArrayBase::TypedArraySize(InstanceType type) {
    return OBJECT_POINTER_ALIGN(kDataOffset + DataSize(type));
  }
  
  
  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()));
    ElementType* ptr = reinterpret_cast<ElementType*>(DataPtr());
    return ptr[index];
  }
  
  
  template <class Traits>
  void FixedTypedArray<Traits>::set(int index, ElementType value) {
    DCHECK((index >= 0) && (index < this->length()));
    ElementType* ptr = reinterpret_cast<ElementType*>(DataPtr());
    ptr[index] = value;
  }
  
  
  template <class Traits>
  typename Traits::ElementType FixedTypedArray<Traits>::from_int(int value) {
    return static_cast<ElementType>(value);
  }
  
  
  template <> inline
  uint8_t FixedTypedArray<Uint8ClampedArrayTraits>::from_int(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_double(
      double value) {
    return static_cast<ElementType>(DoubleToInt32(value));
  }
  
  
  template<> inline
  uint8_t FixedTypedArray<Uint8ClampedArrayTraits>::from_double(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(double value) {
    return static_cast<float>(value);
  }
  
  
  template<> inline
  double FixedTypedArray<Float64ArrayTraits>::from_double(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::cast(value)->value();
      cast_value = from_int(int_value);
    } else if (value->IsHeapNumber()) {
      double double_value = HeapNumber::cast(value)->value();
      cast_value = from_double(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());
    }
    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);
  }
  
  
  int Map::visitor_id() {
    return READ_BYTE_FIELD(this, kVisitorIdOffset);
  }
  
  
  void Map::set_visitor_id(int id) {
    DCHECK(0 <= id && id < 256);
    WRITE_BYTE_FIELD(this, kVisitorIdOffset, static_cast<byte>(id));
  }
  
  
  int Map::instance_size() {
    return NOBARRIER_READ_BYTE_FIELD(
        this, kInstanceSizeOffset) << kPointerSizeLog2;
  }
  
  
  int Map::inobject_properties_or_constructor_function_index() {
    return READ_BYTE_FIELD(this,
                           kInObjectPropertiesOrConstructorFunctionIndexOffset);
  }
  
  
  void Map::set_inobject_properties_or_constructor_function_index(int value) {
    DCHECK(0 <= value && value < 256);
    WRITE_BYTE_FIELD(this, kInObjectPropertiesOrConstructorFunctionIndexOffset,
                     static_cast<byte>(value));
  }
  
  
  int Map::GetInObjectProperties() {
    DCHECK(IsJSObjectMap());
    return inobject_properties_or_constructor_function_index();
  }
  
  
  void Map::SetInObjectProperties(int value) {
    DCHECK(IsJSObjectMap());
    set_inobject_properties_or_constructor_function_index(value);
  }
  
  
  int Map::GetConstructorFunctionIndex() {
    DCHECK(IsPrimitiveMap());
    return inobject_properties_or_constructor_function_index();
  }
  
  
  void Map::SetConstructorFunctionIndex(int value) {
    DCHECK(IsPrimitiveMap());
    set_inobject_properties_or_constructor_function_index(value);
  }
  
  
  int Map::GetInObjectPropertyOffset(int index) {
    // Adjust for the number of properties stored in the object.
    index -= GetInObjectProperties();
    DCHECK(index <= 0);
    return instance_size() + (index * kPointerSize);
  }
  
  
  Handle<Map> Map::AddMissingTransitionsForTesting(
      Handle<Map> split_map, Handle<DescriptorArray> descriptors,
      Handle<LayoutDescriptor> full_layout_descriptor) {
    return AddMissingTransitions(split_map, descriptors, full_layout_descriptor);
  }
  
  
  int HeapObject::SizeFromMap(Map* map) {
    int instance_size = map->instance_size();
    if (instance_size != kVariableSizeSentinel) return instance_size;
    // Only inline the most frequent cases.
    InstanceType instance_type = map->instance_type();
    if (instance_type == FIXED_ARRAY_TYPE ||
        instance_type == TRANSITION_ARRAY_TYPE) {
      return FixedArray::SizeFor(
          reinterpret_cast<FixedArray*>(this)->synchronized_length());
    }
    if (instance_type == ONE_BYTE_STRING_TYPE ||
        instance_type == ONE_BYTE_INTERNALIZED_STRING_TYPE) {
      // Strings may get concurrently truncated, hence we have to access its
      // length synchronized.
      return SeqOneByteString::SizeFor(
          reinterpret_cast<SeqOneByteString*>(this)->synchronized_length());
    }
    if (instance_type == BYTE_ARRAY_TYPE) {
      return reinterpret_cast<ByteArray*>(this)->ByteArraySize();
    }
    if (instance_type == BYTECODE_ARRAY_TYPE) {
      return reinterpret_cast<BytecodeArray*>(this)->BytecodeArraySize();
    }
    if (instance_type == FREE_SPACE_TYPE) {
      return reinterpret_cast<FreeSpace*>(this)->nobarrier_size();
    }
    if (instance_type == STRING_TYPE ||
        instance_type == INTERNALIZED_STRING_TYPE) {
      // Strings may get concurrently truncated, hence we have to access its
      // length synchronized.
      return SeqTwoByteString::SizeFor(
          reinterpret_cast<SeqTwoByteString*>(this)->synchronized_length());
    }
    if (instance_type == FIXED_DOUBLE_ARRAY_TYPE) {
      return FixedDoubleArray::SizeFor(
          reinterpret_cast<FixedDoubleArray*>(this)->length());
    }
    if (instance_type >= FIRST_FIXED_TYPED_ARRAY_TYPE &&
        instance_type <= LAST_FIXED_TYPED_ARRAY_TYPE) {
      return reinterpret_cast<FixedTypedArrayBase*>(
          this)->TypedArraySize(instance_type);
    }
    DCHECK(instance_type == CODE_TYPE);
    return reinterpret_cast<Code*>(this)->CodeSize();
  }
  
  
  void Map::set_instance_size(int value) {
    DCHECK_EQ(0, value & (kPointerSize - 1));
    value >>= kPointerSizeLog2;
    DCHECK(0 <= value && value < 256);
    NOBARRIER_WRITE_BYTE_FIELD(
        this, kInstanceSizeOffset, static_cast<byte>(value));
  }
  
  
  void Map::clear_unused() { WRITE_BYTE_FIELD(this, kUnusedOffset, 0); }
  
  
  InstanceType Map::instance_type() {
    return static_cast<InstanceType>(READ_BYTE_FIELD(this, kInstanceTypeOffset));
  }
  
  
  void Map::set_instance_type(InstanceType value) {
    WRITE_BYTE_FIELD(this, kInstanceTypeOffset, value);
  }
  
  
  int Map::unused_property_fields() {
    return READ_BYTE_FIELD(this, kUnusedPropertyFieldsOffset);
  }
  
  
  void Map::set_unused_property_fields(int value) {
    WRITE_BYTE_FIELD(this, kUnusedPropertyFieldsOffset, Min(value, 255));
  }
  
  
  byte Map::bit_field() const { return READ_BYTE_FIELD(this, kBitFieldOffset); }
  
  
  void Map::set_bit_field(byte value) {
    WRITE_BYTE_FIELD(this, kBitFieldOffset, value);
  }
  
  
  byte Map::bit_field2() const { return READ_BYTE_FIELD(this, kBitField2Offset); }
  
  
  void Map::set_bit_field2(byte value) {
    WRITE_BYTE_FIELD(this, kBitField2Offset, value);
  }
  
  
  void Map::set_non_instance_prototype(bool value) {
    if (value) {
      set_bit_field(bit_field() | (1 << kHasNonInstancePrototype));
    } else {
      set_bit_field(bit_field() & ~(1 << kHasNonInstancePrototype));
    }
  }
  
  
  bool Map::has_non_instance_prototype() {
    return ((1 << kHasNonInstancePrototype) & bit_field()) != 0;
  }
  
  
  void Map::set_is_constructor(bool value) {
    if (value) {
      set_bit_field(bit_field() | (1 << kIsConstructor));
    } else {
      set_bit_field(bit_field() & ~(1 << kIsConstructor));
    }
  }
  
  
  bool Map::is_constructor() const {
    return ((1 << kIsConstructor) & bit_field()) != 0;
  }
  
  void Map::set_has_hidden_prototype(bool value) {
    set_bit_field3(HasHiddenPrototype::update(bit_field3(), value));
  }
  
  bool Map::has_hidden_prototype() const {
    return HasHiddenPrototype::decode(bit_field3());
  }
  
  
  void Map::set_has_indexed_interceptor() {
    set_bit_field(bit_field() | (1 << kHasIndexedInterceptor));
  }
  
  
  bool Map::has_indexed_interceptor() {
    return ((1 << kHasIndexedInterceptor) & bit_field()) != 0;
  }
  
  
  void Map::set_is_undetectable() {
    set_bit_field(bit_field() | (1 << kIsUndetectable));
  }
  
  
  bool Map::is_undetectable() {
    return ((1 << kIsUndetectable) & bit_field()) != 0;
  }
  
  
  void Map::set_is_observed() { set_bit_field(bit_field() | (1 << kIsObserved)); }
  
  bool Map::is_observed() { return ((1 << kIsObserved) & bit_field()) != 0; }
  
  
  void Map::set_has_named_interceptor() {
    set_bit_field(bit_field() | (1 << kHasNamedInterceptor));
  }
  
  
  bool Map::has_named_interceptor() {
    return ((1 << kHasNamedInterceptor) & bit_field()) != 0;
  }
  
  
  void Map::set_is_access_check_needed(bool access_check_needed) {
    if (access_check_needed) {
      set_bit_field(bit_field() | (1 << kIsAccessCheckNeeded));
    } else {
      set_bit_field(bit_field() & ~(1 << kIsAccessCheckNeeded));
    }
  }
  
  
  bool Map::is_access_check_needed() {
    return ((1 << kIsAccessCheckNeeded) & bit_field()) != 0;
  }
  
  
  void Map::set_is_extensible(bool value) {
    if (value) {
      set_bit_field2(bit_field2() | (1 << kIsExtensible));
    } else {
      set_bit_field2(bit_field2() & ~(1 << kIsExtensible));
    }
  }
  
  bool Map::is_extensible() {
    return ((1 << kIsExtensible) & bit_field2()) != 0;
  }
  
  
  void Map::set_is_prototype_map(bool value) {
    set_bit_field2(IsPrototypeMapBits::update(bit_field2(), value));
  }
  
  bool Map::is_prototype_map() const {
    return IsPrototypeMapBits::decode(bit_field2());
  }
  
  
  void Map::set_elements_kind(ElementsKind elements_kind) {
    DCHECK(static_cast<int>(elements_kind) < kElementsKindCount);
    DCHECK(kElementsKindCount <= (1 << Map::ElementsKindBits::kSize));
    set_bit_field2(Map::ElementsKindBits::update(bit_field2(), elements_kind));
    DCHECK(this->elements_kind() == elements_kind);
  }
  
  
  ElementsKind Map::elements_kind() {
    return Map::ElementsKindBits::decode(bit_field2());
  }
  
  
  bool Map::has_fast_smi_elements() {
    return IsFastSmiElementsKind(elements_kind());
  }
  
  bool Map::has_fast_object_elements() {
    return IsFastObjectElementsKind(elements_kind());
  }
  
  bool Map::has_fast_smi_or_object_elements() {
    return IsFastSmiOrObjectElementsKind(elements_kind());
  }
  
  bool Map::has_fast_double_elements() {
    return IsFastDoubleElementsKind(elements_kind());
  }
  
  bool Map::has_fast_elements() { return IsFastElementsKind(elements_kind()); }
  
  bool Map::has_sloppy_arguments_elements() {
    return IsSloppyArgumentsElements(elements_kind());
  }
  
  bool Map::has_fast_string_wrapper_elements() {
    return elements_kind() == FAST_STRING_WRAPPER_ELEMENTS;
  }
  
  bool Map::has_fixed_typed_array_elements() {
    return IsFixedTypedArrayElementsKind(elements_kind());
  }
  
  bool Map::has_dictionary_elements() {
    return IsDictionaryElementsKind(elements_kind());
  }
  
  
  void Map::set_dictionary_map(bool value) {
    uint32_t new_bit_field3 = DictionaryMap::update(bit_field3(), value);
    new_bit_field3 = IsUnstable::update(new_bit_field3, value);
    set_bit_field3(new_bit_field3);
  }
  
  
  bool Map::is_dictionary_map() {
    return DictionaryMap::decode(bit_field3());
  }
  
  
  Code::Flags Code::flags() {
    return static_cast<Flags>(READ_INT_FIELD(this, kFlagsOffset));
  }
  
  
  void Map::set_owns_descriptors(bool owns_descriptors) {
    set_bit_field3(OwnsDescriptors::update(bit_field3(), owns_descriptors));
  }
  
  
  bool Map::owns_descriptors() {
    return OwnsDescriptors::decode(bit_field3());
  }
  
  
  void Map::set_is_callable() { set_bit_field(bit_field() | (1 << kIsCallable)); }
  
  
  bool Map::is_callable() const {
    return ((1 << kIsCallable) & bit_field()) != 0;
  }
  
  
  void Map::deprecate() {
    set_bit_field3(Deprecated::update(bit_field3(), true));
  }
  
  
  bool Map::is_deprecated() {
    return Deprecated::decode(bit_field3());
  }
  
  
  void Map::set_migration_target(bool value) {
    set_bit_field3(IsMigrationTarget::update(bit_field3(), value));
  }
  
  
  bool Map::is_migration_target() {
    return IsMigrationTarget::decode(bit_field3());
  }
  
  
  void Map::set_new_target_is_base(bool value) {
    set_bit_field3(NewTargetIsBase::update(bit_field3(), value));
  }
  
  
  bool Map::new_target_is_base() { return NewTargetIsBase::decode(bit_field3()); }
  
  
  void Map::set_construction_counter(int value) {
    set_bit_field3(ConstructionCounter::update(bit_field3(), value));
  }
  
  
  int Map::construction_counter() {
    return ConstructionCounter::decode(bit_field3());
  }
  
  
  void Map::mark_unstable() {
    set_bit_field3(IsUnstable::update(bit_field3(), true));
  }
  
  
  bool Map::is_stable() {
    return !IsUnstable::decode(bit_field3());
  }
  
  
  bool Map::has_code_cache() {
    return code_cache() != GetIsolate()->heap()->empty_fixed_array();
  }
  
  
  bool Map::CanBeDeprecated() {
    int descriptor = LastAdded();
    for (int i = 0; i <= descriptor; i++) {
      PropertyDetails details = instance_descriptors()->GetDetails(i);
      if (details.representation().IsNone()) return true;
      if (details.representation().IsSmi()) return true;
      if (details.representation().IsDouble()) return true;
      if (details.representation().IsHeapObject()) return true;
      if (details.type() == DATA_CONSTANT) return true;
    }
    return false;
  }
  
  
  void Map::NotifyLeafMapLayoutChange() {
    if (is_stable()) {
      mark_unstable();
      dependent_code()->DeoptimizeDependentCodeGroup(
          GetIsolate(),
          DependentCode::kPrototypeCheckGroup);
    }
  }
  
  
  bool Map::CanTransition() {
    // Only JSObject and subtypes have map transitions and back pointers.
    STATIC_ASSERT(LAST_TYPE == LAST_JS_OBJECT_TYPE);
    return instance_type() >= FIRST_JS_OBJECT_TYPE;
  }
  
  
  bool Map::IsBooleanMap() { return this == GetHeap()->boolean_map(); }
  bool Map::IsPrimitiveMap() {
    STATIC_ASSERT(FIRST_PRIMITIVE_TYPE == FIRST_TYPE);
    return instance_type() <= LAST_PRIMITIVE_TYPE;
  }
  bool Map::IsJSReceiverMap() {
    STATIC_ASSERT(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
    return instance_type() >= FIRST_JS_RECEIVER_TYPE;
  }
  bool Map::IsJSObjectMap() {
    STATIC_ASSERT(LAST_JS_OBJECT_TYPE == LAST_TYPE);
    return instance_type() >= FIRST_JS_OBJECT_TYPE;
  }
  bool Map::IsJSArrayMap() { return instance_type() == JS_ARRAY_TYPE; }
  bool Map::IsJSFunctionMap() { return instance_type() == JS_FUNCTION_TYPE; }
  bool Map::IsStringMap() { return instance_type() < FIRST_NONSTRING_TYPE; }
  bool Map::IsJSProxyMap() { return instance_type() == JS_PROXY_TYPE; }
  bool Map::IsJSGlobalProxyMap() {
    return instance_type() == JS_GLOBAL_PROXY_TYPE;
  }
  bool Map::IsJSGlobalObjectMap() {
    return instance_type() == JS_GLOBAL_OBJECT_TYPE;
  }
  bool Map::IsJSTypedArrayMap() { return instance_type() == JS_TYPED_ARRAY_TYPE; }
  bool Map::IsJSDataViewMap() { return instance_type() == JS_DATA_VIEW_TYPE; }
  
  
  bool Map::CanOmitMapChecks() {
    return is_stable() && FLAG_omit_map_checks_for_leaf_maps;
  }
  
  
  DependentCode* DependentCode::next_link() {
    return DependentCode::cast(get(kNextLinkIndex));
  }
  
  
  void DependentCode::set_next_link(DependentCode* next) {
    set(kNextLinkIndex, next);
  }
  
  
  int DependentCode::flags() { return Smi::cast(get(kFlagsIndex))->value(); }
  
  
  void DependentCode::set_flags(int flags) {
    set(kFlagsIndex, Smi::FromInt(flags));
  }
  
  
  int DependentCode::count() { return CountField::decode(flags()); }
  
  void DependentCode::set_count(int value) {
    set_flags(CountField::update(flags(), value));
  }
  
  
  DependentCode::DependencyGroup DependentCode::group() {
    return static_cast<DependencyGroup>(GroupField::decode(flags()));
  }
  
  
  void DependentCode::set_group(DependentCode::DependencyGroup group) {
    set_flags(GroupField::update(flags(), static_cast<int>(group)));
  }
  
  
  void DependentCode::set_object_at(int i, Object* object) {
    set(kCodesStartIndex + i, object);
  }
  
  
  Object* DependentCode::object_at(int i) {
    return get(kCodesStartIndex + i);
  }
  
  
  void DependentCode::clear_at(int i) {
    set_undefined(kCodesStartIndex + i);
  }
  
  
  void DependentCode::copy(int from, int to) {
    set(kCodesStartIndex + to, get(kCodesStartIndex + from));
  }
  
  
  void Code::set_flags(Code::Flags flags) {
    STATIC_ASSERT(Code::NUMBER_OF_KINDS <= KindField::kMax + 1);
    WRITE_INT_FIELD(this, kFlagsOffset, flags);
  }
  
  
  Code::Kind Code::kind() {
    return ExtractKindFromFlags(flags());
  }
  
  
  bool Code::IsCodeStubOrIC() {
    return kind() == STUB || kind() == HANDLER || kind() == LOAD_IC ||
           kind() == KEYED_LOAD_IC || kind() == CALL_IC || kind() == STORE_IC ||
           kind() == KEYED_STORE_IC || kind() == BINARY_OP_IC ||
           kind() == COMPARE_IC || kind() == TO_BOOLEAN_IC;
  }
  
  
  bool Code::IsJavaScriptCode() {
    return kind() == FUNCTION || kind() == OPTIMIZED_FUNCTION ||
           is_interpreter_entry_trampoline();
  }
  
  
  InlineCacheState Code::ic_state() {
    InlineCacheState result = ExtractICStateFromFlags(flags());
    // Only allow uninitialized or debugger states for non-IC code
    // objects. This is used in the debugger to determine whether or not
    // a call to code object has been replaced with a debug break call.
    DCHECK(is_inline_cache_stub() ||
           result == UNINITIALIZED ||
           result == DEBUG_STUB);
    return result;
  }
  
  
  ExtraICState Code::extra_ic_state() {
    DCHECK(is_inline_cache_stub() || ic_state() == DEBUG_STUB);
    return ExtractExtraICStateFromFlags(flags());
  }
  
  
  Code::StubType Code::type() {
    return ExtractTypeFromFlags(flags());
  }
  
  // For initialization.
  void Code::set_raw_kind_specific_flags1(int value) {
    WRITE_INT_FIELD(this, kKindSpecificFlags1Offset, value);
  }
  
  
  void Code::set_raw_kind_specific_flags2(int value) {
    WRITE_INT_FIELD(this, kKindSpecificFlags2Offset, value);
  }
  
  
  inline bool Code::is_crankshafted() {
    return IsCrankshaftedField::decode(
        READ_UINT32_FIELD(this, kKindSpecificFlags2Offset));
  }
  
  
  inline bool Code::is_hydrogen_stub() {
    return is_crankshafted() && kind() != OPTIMIZED_FUNCTION;
  }
  
  
  inline bool Code::is_interpreter_entry_trampoline() {
    Handle<Code> interpreter_entry =
        GetIsolate()->builtins()->InterpreterEntryTrampoline();
    return interpreter_entry.location() != nullptr && *interpreter_entry == this;
  }
  
  inline bool Code::is_interpreter_enter_bytecode_dispatch() {
    Handle<Code> interpreter_handler =
        GetIsolate()->builtins()->InterpreterEnterBytecodeDispatch();
    return interpreter_handler.location() != nullptr &&
           *interpreter_handler == this;
  }
  
  inline void Code::set_is_crankshafted(bool value) {
    int previous = READ_UINT32_FIELD(this, kKindSpecificFlags2Offset);
    int updated = IsCrankshaftedField::update(previous, value);
    WRITE_UINT32_FIELD(this, kKindSpecificFlags2Offset, updated);
  }
  
  
  inline bool Code::is_turbofanned() {
    return IsTurbofannedField::decode(
        READ_UINT32_FIELD(this, kKindSpecificFlags1Offset));
  }
  
  
  inline void Code::set_is_turbofanned(bool value) {
    int previous = READ_UINT32_FIELD(this, kKindSpecificFlags1Offset);
    int updated = IsTurbofannedField::update(previous, value);
    WRITE_UINT32_FIELD(this, kKindSpecificFlags1Offset, updated);
  }
  
  
  inline bool Code::can_have_weak_objects() {
    DCHECK(kind() == OPTIMIZED_FUNCTION);
    return CanHaveWeakObjectsField::decode(
        READ_UINT32_FIELD(this, kKindSpecificFlags1Offset));
  }
  
  
  inline void Code::set_can_have_weak_objects(bool value) {
    DCHECK(kind() == OPTIMIZED_FUNCTION);
    int previous = READ_UINT32_FIELD(this, kKindSpecificFlags1Offset);
    int updated = CanHaveWeakObjectsField::update(previous, value);
    WRITE_UINT32_FIELD(this, kKindSpecificFlags1Offset, updated);
  }
  
  
  bool Code::has_deoptimization_support() {
    DCHECK_EQ(FUNCTION, kind());
    unsigned flags = READ_UINT32_FIELD(this, kFullCodeFlags);
    return FullCodeFlagsHasDeoptimizationSupportField::decode(flags);
  }
  
  
  void Code::set_has_deoptimization_support(bool value) {
    DCHECK_EQ(FUNCTION, kind());
    unsigned flags = READ_UINT32_FIELD(this, kFullCodeFlags);
    flags = FullCodeFlagsHasDeoptimizationSupportField::update(flags, value);
    WRITE_UINT32_FIELD(this, kFullCodeFlags, flags);
  }
  
  
  bool Code::has_debug_break_slots() {
    DCHECK_EQ(FUNCTION, kind());
    unsigned flags = READ_UINT32_FIELD(this, kFullCodeFlags);
    return FullCodeFlagsHasDebugBreakSlotsField::decode(flags);
  }
  
  
  void Code::set_has_debug_break_slots(bool value) {
    DCHECK_EQ(FUNCTION, kind());
    unsigned flags = READ_UINT32_FIELD(this, kFullCodeFlags);
    flags = FullCodeFlagsHasDebugBreakSlotsField::update(flags, value);
    WRITE_UINT32_FIELD(this, kFullCodeFlags, flags);
  }
  
  
  bool Code::has_reloc_info_for_serialization() {
    DCHECK_EQ(FUNCTION, kind());
    unsigned flags = READ_UINT32_FIELD(this, kFullCodeFlags);
    return FullCodeFlagsHasRelocInfoForSerialization::decode(flags);
  }
  
  
  void Code::set_has_reloc_info_for_serialization(bool value) {
    DCHECK_EQ(FUNCTION, kind());
    unsigned flags = READ_UINT32_FIELD(this, kFullCodeFlags);
    flags = FullCodeFlagsHasRelocInfoForSerialization::update(flags, value);
    WRITE_UINT32_FIELD(this, kFullCodeFlags, flags);
  }
  
  
  int Code::allow_osr_at_loop_nesting_level() {
    DCHECK_EQ(FUNCTION, kind());
    int fields = READ_UINT32_FIELD(this, kKindSpecificFlags2Offset);
    return AllowOSRAtLoopNestingLevelField::decode(fields);
  }
  
  
  void Code::set_allow_osr_at_loop_nesting_level(int level) {
    DCHECK_EQ(FUNCTION, kind());
    DCHECK(level >= 0 && level <= kMaxLoopNestingMarker);
    int previous = READ_UINT32_FIELD(this, kKindSpecificFlags2Offset);
    int updated = AllowOSRAtLoopNestingLevelField::update(previous, level);
    WRITE_UINT32_FIELD(this, kKindSpecificFlags2Offset, updated);
  }
  
  
  int Code::profiler_ticks() {
    DCHECK_EQ(FUNCTION, kind());
    return ProfilerTicksField::decode(
        READ_UINT32_FIELD(this, kKindSpecificFlags1Offset));
  }
  
  
  void Code::set_profiler_ticks(int ticks) {
    if (kind() == FUNCTION) {
      unsigned previous = READ_UINT32_FIELD(this, kKindSpecificFlags1Offset);
      unsigned updated = ProfilerTicksField::update(previous, ticks);
      WRITE_UINT32_FIELD(this, kKindSpecificFlags1Offset, updated);
    }
  }
  
  int Code::builtin_index() { return READ_INT_FIELD(this, kBuiltinIndexOffset); }
  
  void Code::set_builtin_index(int index) {
    WRITE_INT_FIELD(this, kBuiltinIndexOffset, index);
  }
  
  
  unsigned Code::stack_slots() {
    DCHECK(is_crankshafted());
    return StackSlotsField::decode(
        READ_UINT32_FIELD(this, kKindSpecificFlags1Offset));
  }
  
  
  void Code::set_stack_slots(unsigned slots) {
    CHECK(slots <= (1 << kStackSlotsBitCount));
    DCHECK(is_crankshafted());
    int previous = READ_UINT32_FIELD(this, kKindSpecificFlags1Offset);
    int updated = StackSlotsField::update(previous, slots);
    WRITE_UINT32_FIELD(this, kKindSpecificFlags1Offset, updated);
  }
  
  
  unsigned Code::safepoint_table_offset() {
    DCHECK(is_crankshafted());
    return SafepointTableOffsetField::decode(
        READ_UINT32_FIELD(this, kKindSpecificFlags2Offset));
  }
  
  
  void Code::set_safepoint_table_offset(unsigned offset) {
    CHECK(offset <= (1 << kSafepointTableOffsetBitCount));
    DCHECK(is_crankshafted());
    DCHECK(IsAligned(offset, static_cast<unsigned>(kIntSize)));
    int previous = READ_UINT32_FIELD(this, kKindSpecificFlags2Offset);
    int updated = SafepointTableOffsetField::update(previous, offset);
    WRITE_UINT32_FIELD(this, kKindSpecificFlags2Offset, updated);
  }
  
  
  unsigned Code::back_edge_table_offset() {
    DCHECK_EQ(FUNCTION, kind());
    return BackEdgeTableOffsetField::decode(
        READ_UINT32_FIELD(this, kKindSpecificFlags2Offset)) << kPointerSizeLog2;
  }
  
  
  void Code::set_back_edge_table_offset(unsigned offset) {
    DCHECK_EQ(FUNCTION, kind());
    DCHECK(IsAligned(offset, static_cast<unsigned>(kPointerSize)));
    offset = offset >> kPointerSizeLog2;
    int previous = READ_UINT32_FIELD(this, kKindSpecificFlags2Offset);
    int updated = BackEdgeTableOffsetField::update(previous, offset);
    WRITE_UINT32_FIELD(this, kKindSpecificFlags2Offset, updated);
  }
  
  
  bool Code::back_edges_patched_for_osr() {
    DCHECK_EQ(FUNCTION, kind());
    return allow_osr_at_loop_nesting_level() > 0;
  }
  
  
  uint16_t Code::to_boolean_state() { return extra_ic_state(); }
  
  
  bool Code::marked_for_deoptimization() {
    DCHECK(kind() == OPTIMIZED_FUNCTION);
    return MarkedForDeoptimizationField::decode(
        READ_UINT32_FIELD(this, kKindSpecificFlags1Offset));
  }
  
  
  void Code::set_marked_for_deoptimization(bool flag) {
    DCHECK(kind() == OPTIMIZED_FUNCTION);
    DCHECK(!flag || AllowDeoptimization::IsAllowed(GetIsolate()));
    int previous = READ_UINT32_FIELD(this, kKindSpecificFlags1Offset);
    int updated = MarkedForDeoptimizationField::update(previous, flag);
    WRITE_UINT32_FIELD(this, kKindSpecificFlags1Offset, updated);
  }
  
  
  bool Code::is_inline_cache_stub() {
    Kind kind = this->kind();
    switch (kind) {
  #define CASE(name) case name: return true;
      IC_KIND_LIST(CASE)
  #undef CASE
      default: return false;
    }
  }
  
  
  bool Code::is_keyed_stub() {
    return is_keyed_load_stub() || is_keyed_store_stub();
  }
  
  
  bool Code::is_debug_stub() { return ic_state() == DEBUG_STUB; }
  bool Code::is_handler() { return kind() == HANDLER; }
  bool Code::is_load_stub() { return kind() == LOAD_IC; }
  bool Code::is_keyed_load_stub() { return kind() == KEYED_LOAD_IC; }
  bool Code::is_store_stub() { return kind() == STORE_IC; }
  bool Code::is_keyed_store_stub() { return kind() == KEYED_STORE_IC; }
  bool Code::is_call_stub() { return kind() == CALL_IC; }
  bool Code::is_binary_op_stub() { return kind() == BINARY_OP_IC; }
  bool Code::is_compare_ic_stub() { return kind() == COMPARE_IC; }
  bool Code::is_to_boolean_ic_stub() { return kind() == TO_BOOLEAN_IC; }
  bool Code::is_optimized_code() { return kind() == OPTIMIZED_FUNCTION; }
  bool Code::is_wasm_code() { return kind() == WASM_FUNCTION; }
  
  bool Code::embeds_maps_weakly() {
    Kind k = kind();
    return (k == LOAD_IC || k == STORE_IC || k == KEYED_LOAD_IC ||
            k == KEYED_STORE_IC) &&
           ic_state() == MONOMORPHIC;
  }
  
  
  Address Code::constant_pool() {
    Address constant_pool = NULL;
    if (FLAG_enable_embedded_constant_pool) {
      int offset = constant_pool_offset();
      if (offset < instruction_size()) {
        constant_pool = FIELD_ADDR(this, kHeaderSize + offset);
      }
    }
    return constant_pool;
  }
  
  Code::Flags Code::ComputeFlags(Kind kind, InlineCacheState ic_state,
                                 ExtraICState extra_ic_state, StubType type,
                                 CacheHolderFlag holder) {
    // Compute the bit mask.
    unsigned int bits = KindField::encode(kind) | ICStateField::encode(ic_state) |
                        TypeField::encode(type) |
                        ExtraICStateField::encode(extra_ic_state) |
                        CacheHolderField::encode(holder);
    return static_cast<Flags>(bits);
  }
  
  Code::Flags Code::ComputeMonomorphicFlags(Kind kind,
                                            ExtraICState extra_ic_state,
                                            CacheHolderFlag holder,
                                            StubType type) {
    return ComputeFlags(kind, MONOMORPHIC, extra_ic_state, type, holder);
  }
  
  
  Code::Flags Code::ComputeHandlerFlags(Kind handler_kind, StubType type,
                                        CacheHolderFlag holder) {
    return ComputeFlags(Code::HANDLER, MONOMORPHIC, handler_kind, type, holder);
  }
  
  
  Code::Kind Code::ExtractKindFromFlags(Flags flags) {
    return KindField::decode(flags);
  }
  
  
  InlineCacheState Code::ExtractICStateFromFlags(Flags flags) {
    return ICStateField::decode(flags);
  }
  
  
  ExtraICState Code::ExtractExtraICStateFromFlags(Flags flags) {
    return ExtraICStateField::decode(flags);
  }
  
  
  Code::StubType Code::ExtractTypeFromFlags(Flags flags) {
    return TypeField::decode(flags);
  }
  
  CacheHolderFlag Code::ExtractCacheHolderFromFlags(Flags flags) {
    return CacheHolderField::decode(flags);
  }
  
  
  Code::Flags Code::RemoveTypeFromFlags(Flags flags) {
    int bits = flags & ~TypeField::kMask;
    return static_cast<Flags>(bits);
  }
  
  
  Code::Flags Code::RemoveTypeAndHolderFromFlags(Flags flags) {
    int bits = flags & ~TypeField::kMask & ~CacheHolderField::kMask;
    return static_cast<Flags>(bits);
  }
  
  
  Code* Code::GetCodeFromTargetAddress(Address address) {
    HeapObject* code = HeapObject::FromAddress(address - Code::kHeaderSize);
    // GetCodeFromTargetAddress might be called when marking objects during mark
    // sweep. reinterpret_cast is therefore used instead of the more appropriate
    // Code::cast. Code::cast does not work when the object's map is
    // marked.
    Code* result = reinterpret_cast<Code*>(code);
    return result;
  }
  
  
  Object* Code::GetObjectFromEntryAddress(Address location_of_address) {
    return HeapObject::
        FromAddress(Memory::Address_at(location_of_address) - Code::kHeaderSize);
  }
  
  
  bool Code::CanContainWeakObjects() {
    return is_optimized_code() && can_have_weak_objects();
  }
  
  
  bool Code::IsWeakObject(Object* object) {
    return (CanContainWeakObjects() && IsWeakObjectInOptimizedCode(object));
  }
  
  
  bool Code::IsWeakObjectInOptimizedCode(Object* object) {
    if (object->IsMap()) {
      return Map::cast(object)->CanTransition() &&
             FLAG_weak_embedded_maps_in_optimized_code;
    }
    if (object->IsCell()) {
      object = Cell::cast(object)->value();
    } else if (object->IsPropertyCell()) {
      object = PropertyCell::cast(object)->value();
    }
    if (object->IsJSReceiver()) {
      return FLAG_weak_embedded_objects_in_optimized_code;
    }
    if (object->IsContext()) {
      // Contexts of inlined functions are embedded in optimized code.
      return FLAG_weak_embedded_objects_in_optimized_code;
    }
    return false;
  }
  
  
  class Code::FindAndReplacePattern {
   public:
    FindAndReplacePattern() : count_(0) { }
    void Add(Handle<Map> map_to_find, Handle<Object> obj_to_replace) {
      DCHECK(count_ < kMaxCount);
      find_[count_] = map_to_find;
      replace_[count_] = obj_to_replace;
      ++count_;
    }
   private:
    static const int kMaxCount = 4;
    int count_;
    Handle<Map> find_[kMaxCount];
    Handle<Object> replace_[kMaxCount];
    friend class Code;
  };
  
  int AbstractCode::instruction_size() {
    if (IsCode()) {
      return GetCode()->instruction_size();
    } else {
      return GetBytecodeArray()->length();
    }
  }
  
  int AbstractCode::ExecutableSize() {
    if (IsCode()) {
      return GetCode()->ExecutableSize();
    } else {
      return GetBytecodeArray()->BytecodeArraySize();
    }
  }
  
  Address AbstractCode::instruction_start() {
    if (IsCode()) {
      return GetCode()->instruction_start();
    } else {
      return GetBytecodeArray()->GetFirstBytecodeAddress();
    }
  }
  
  Address AbstractCode::instruction_end() {
    if (IsCode()) {
      return GetCode()->instruction_end();
    } else {
      return GetBytecodeArray()->GetFirstBytecodeAddress() +
             GetBytecodeArray()->length();
    }
  }
  
  bool AbstractCode::contains(byte* inner_pointer) {
    return (address() <= inner_pointer) && (inner_pointer <= address() + Size());
  }
  
  AbstractCode::Kind AbstractCode::kind() {
    if (IsCode()) {
      STATIC_ASSERT(AbstractCode::FUNCTION ==
                    static_cast<AbstractCode::Kind>(Code::FUNCTION));
      return static_cast<AbstractCode::Kind>(GetCode()->kind());
    } else {
      return INTERPRETED_FUNCTION;
    }
  }
  
  Code* AbstractCode::GetCode() { return Code::cast(this); }
  
  BytecodeArray* AbstractCode::GetBytecodeArray() {
    return BytecodeArray::cast(this);
  }
  
  Object* Map::prototype() const {
    return READ_FIELD(this, kPrototypeOffset);
  }
  
  
  void Map::set_prototype(Object* value, WriteBarrierMode mode) {
    DCHECK(value->IsNull() || value->IsJSReceiver());
    WRITE_FIELD(this, kPrototypeOffset, value);
    CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kPrototypeOffset, value, mode);
  }
  
  
  LayoutDescriptor* Map::layout_descriptor_gc_safe() {
    Object* layout_desc = READ_FIELD(this, kLayoutDecriptorOffset);
    return LayoutDescriptor::cast_gc_safe(layout_desc);
  }
  
  
  bool Map::HasFastPointerLayout() const {
    Object* layout_desc = READ_FIELD(this, kLayoutDecriptorOffset);
    return LayoutDescriptor::IsFastPointerLayout(layout_desc);
  }
  
  
  void Map::UpdateDescriptors(DescriptorArray* descriptors,
                              LayoutDescriptor* layout_desc) {
    set_instance_descriptors(descriptors);
    if (FLAG_unbox_double_fields) {
      if (layout_descriptor()->IsSlowLayout()) {
        set_layout_descriptor(layout_desc);
      }
  #ifdef VERIFY_HEAP
      // TODO(ishell): remove these checks from VERIFY_HEAP mode.
      if (FLAG_verify_heap) {
        CHECK(layout_descriptor()->IsConsistentWithMap(this));
        CHECK(visitor_id() == Heap::GetStaticVisitorIdForMap(this));
      }
  #else
      SLOW_DCHECK(layout_descriptor()->IsConsistentWithMap(this));
      DCHECK(visitor_id() == Heap::GetStaticVisitorIdForMap(this));
  #endif
    }
  }
  
  
  void Map::InitializeDescriptors(DescriptorArray* descriptors,
                                  LayoutDescriptor* layout_desc) {
    int len = descriptors->number_of_descriptors();
    set_instance_descriptors(descriptors);
    SetNumberOfOwnDescriptors(len);
  
    if (FLAG_unbox_double_fields) {
      set_layout_descriptor(layout_desc);
  #ifdef VERIFY_HEAP
      // TODO(ishell): remove these checks from VERIFY_HEAP mode.
      if (FLAG_verify_heap) {
        CHECK(layout_descriptor()->IsConsistentWithMap(this));
      }
  #else
      SLOW_DCHECK(layout_descriptor()->IsConsistentWithMap(this));
  #endif
      set_visitor_id(Heap::GetStaticVisitorIdForMap(this));
    }
  }
  
  
  ACCESSORS(Map, instance_descriptors, DescriptorArray, kDescriptorsOffset)
  ACCESSORS(Map, layout_descriptor, LayoutDescriptor, kLayoutDecriptorOffset)
  
  
  void Map::set_bit_field3(uint32_t bits) {
    if (kInt32Size != kPointerSize) {
      WRITE_UINT32_FIELD(this, kBitField3Offset + kInt32Size, 0);
    }
    WRITE_UINT32_FIELD(this, kBitField3Offset, bits);
  }
  
  
  uint32_t Map::bit_field3() const {
    return READ_UINT32_FIELD(this, kBitField3Offset);
  }
  
  
  LayoutDescriptor* Map::GetLayoutDescriptor() {
    return FLAG_unbox_double_fields ? layout_descriptor()
                                    : LayoutDescriptor::FastPointerLayout();
  }
  
  
  void Map::AppendDescriptor(Descriptor* desc) {
    DescriptorArray* descriptors = instance_descriptors();
    int number_of_own_descriptors = NumberOfOwnDescriptors();
    DCHECK(descriptors->number_of_descriptors() == number_of_own_descriptors);
    descriptors->Append(desc);
    SetNumberOfOwnDescriptors(number_of_own_descriptors + 1);
  
  // This function does not support appending double field descriptors and
  // it should never try to (otherwise, layout descriptor must be updated too).
  #ifdef DEBUG
    PropertyDetails details = desc->GetDetails();
    CHECK(details.type() != DATA || !details.representation().IsDouble());
  #endif
  }
  
  
  Object* Map::GetBackPointer() {
    Object* object = constructor_or_backpointer();
    if (object->IsMap()) {
      return object;
    }
    return GetIsolate()->heap()->undefined_value();
  }
  
  
  Map* Map::ElementsTransitionMap() {
    return TransitionArray::SearchSpecial(
        this, GetHeap()->elements_transition_symbol());
  }
  
  
  ACCESSORS(Map, raw_transitions, Object, kTransitionsOrPrototypeInfoOffset)
  
  
  Object* Map::prototype_info() const {
    DCHECK(is_prototype_map());
    return READ_FIELD(this, Map::kTransitionsOrPrototypeInfoOffset);
  }
  
  
  void Map::set_prototype_info(Object* value, WriteBarrierMode mode) {
    DCHECK(is_prototype_map());
    WRITE_FIELD(this, Map::kTransitionsOrPrototypeInfoOffset, value);
    CONDITIONAL_WRITE_BARRIER(
        GetHeap(), this, Map::kTransitionsOrPrototypeInfoOffset, value, mode);
  }
  
  
  void Map::SetBackPointer(Object* value, WriteBarrierMode mode) {
    DCHECK(instance_type() >= FIRST_JS_RECEIVER_TYPE);
    DCHECK((value->IsMap() && GetBackPointer()->IsUndefined()));
    DCHECK(!value->IsMap() ||
           Map::cast(value)->GetConstructor() == constructor_or_backpointer());
    set_constructor_or_backpointer(value, mode);
  }
  
  
  ACCESSORS(Map, code_cache, Object, kCodeCacheOffset)
  ACCESSORS(Map, dependent_code, DependentCode, kDependentCodeOffset)
  ACCESSORS(Map, weak_cell_cache, Object, kWeakCellCacheOffset)
  ACCESSORS(Map, constructor_or_backpointer, Object,
            kConstructorOrBackPointerOffset)
  
  
  Object* Map::GetConstructor() const {
    Object* maybe_constructor = constructor_or_backpointer();
    // Follow any back pointers.
    while (maybe_constructor->IsMap()) {
      maybe_constructor =
          Map::cast(maybe_constructor)->constructor_or_backpointer();
    }
    return maybe_constructor;
  }
  
  
  void Map::SetConstructor(Object* constructor, WriteBarrierMode mode) {
    // Never overwrite a back pointer with a constructor.
    DCHECK(!constructor_or_backpointer()->IsMap());
    set_constructor_or_backpointer(constructor, mode);
  }
  
  
  Handle<Map> Map::CopyInitialMap(Handle<Map> map) {
    return CopyInitialMap(map, map->instance_size(), map->GetInObjectProperties(),
                          map->unused_property_fields());
  }
  
  
  ACCESSORS(JSBoundFunction, length, Object, kLengthOffset)
  ACCESSORS(JSBoundFunction, name, Object, kNameOffset)
  ACCESSORS(JSBoundFunction, bound_target_function, JSReceiver,
            kBoundTargetFunctionOffset)
  ACCESSORS(JSBoundFunction, bound_this, Object, kBoundThisOffset)
  ACCESSORS(JSBoundFunction, bound_arguments, FixedArray, kBoundArgumentsOffset)
  
  ACCESSORS(JSFunction, shared, SharedFunctionInfo, kSharedFunctionInfoOffset)
  ACCESSORS(JSFunction, literals, LiteralsArray, kLiteralsOffset)
  ACCESSORS(JSFunction, next_function_link, Object, kNextFunctionLinkOffset)
  
  ACCESSORS(JSGlobalObject, native_context, Context, kNativeContextOffset)
  ACCESSORS(JSGlobalObject, global_proxy, JSObject, kGlobalProxyOffset)
  
  ACCESSORS(JSGlobalProxy, native_context, Object, kNativeContextOffset)
  ACCESSORS(JSGlobalProxy, hash, Object, kHashOffset)
  
  ACCESSORS(AccessorInfo, name, Object, kNameOffset)
  SMI_ACCESSORS(AccessorInfo, flag, kFlagOffset)
  ACCESSORS(AccessorInfo, expected_receiver_type, Object,
            kExpectedReceiverTypeOffset)
  
  ACCESSORS(AccessorInfo, getter, Object, kGetterOffset)
  ACCESSORS(AccessorInfo, setter, Object, kSetterOffset)
  ACCESSORS(AccessorInfo, data, Object, kDataOffset)
  
  ACCESSORS(Box, value, Object, kValueOffset)
  
  ACCESSORS(PrototypeInfo, prototype_users, Object, kPrototypeUsersOffset)
  SMI_ACCESSORS(PrototypeInfo, registry_slot, kRegistrySlotOffset)
  ACCESSORS(PrototypeInfo, validity_cell, Object, kValidityCellOffset)
  
  ACCESSORS(SloppyBlockWithEvalContextExtension, scope_info, ScopeInfo,
            kScopeInfoOffset)
  ACCESSORS(SloppyBlockWithEvalContextExtension, extension, JSObject,
            kExtensionOffset)
  
  ACCESSORS(AccessorPair, getter, Object, kGetterOffset)
  ACCESSORS(AccessorPair, setter, Object, kSetterOffset)
  
  ACCESSORS(AccessCheckInfo, named_callback, Object, kNamedCallbackOffset)
  ACCESSORS(AccessCheckInfo, indexed_callback, Object, kIndexedCallbackOffset)
  ACCESSORS(AccessCheckInfo, callback, Object, kCallbackOffset)
  ACCESSORS(AccessCheckInfo, data, Object, kDataOffset)
  
  ACCESSORS(InterceptorInfo, getter, Object, kGetterOffset)
  ACCESSORS(InterceptorInfo, setter, Object, kSetterOffset)
  ACCESSORS(InterceptorInfo, query, Object, kQueryOffset)
  ACCESSORS(InterceptorInfo, deleter, Object, kDeleterOffset)
  ACCESSORS(InterceptorInfo, enumerator, Object, kEnumeratorOffset)
  ACCESSORS(InterceptorInfo, data, Object, kDataOffset)
  SMI_ACCESSORS(InterceptorInfo, flags, kFlagsOffset)
  BOOL_ACCESSORS(InterceptorInfo, flags, can_intercept_symbols,
                 kCanInterceptSymbolsBit)
  BOOL_ACCESSORS(InterceptorInfo, flags, all_can_read, kAllCanReadBit)
  BOOL_ACCESSORS(InterceptorInfo, flags, non_masking, kNonMasking)
  
  ACCESSORS(CallHandlerInfo, callback, Object, kCallbackOffset)
  ACCESSORS(CallHandlerInfo, data, Object, kDataOffset)
  ACCESSORS(CallHandlerInfo, fast_handler, Object, kFastHandlerOffset)
  
  ACCESSORS(TemplateInfo, tag, Object, kTagOffset)
  ACCESSORS(TemplateInfo, serial_number, Object, kSerialNumberOffset)
  SMI_ACCESSORS(TemplateInfo, number_of_properties, kNumberOfProperties)
  ACCESSORS(TemplateInfo, property_list, Object, kPropertyListOffset)
  ACCESSORS(TemplateInfo, property_accessors, Object, kPropertyAccessorsOffset)
  
  ACCESSORS(FunctionTemplateInfo, call_code, Object, kCallCodeOffset)
  ACCESSORS(FunctionTemplateInfo, prototype_template, Object,
            kPrototypeTemplateOffset)
  ACCESSORS(FunctionTemplateInfo, parent_template, Object, kParentTemplateOffset)
  ACCESSORS(FunctionTemplateInfo, named_property_handler, Object,
            kNamedPropertyHandlerOffset)
  ACCESSORS(FunctionTemplateInfo, indexed_property_handler, Object,
            kIndexedPropertyHandlerOffset)
  ACCESSORS(FunctionTemplateInfo, instance_template, Object,
            kInstanceTemplateOffset)
  ACCESSORS(FunctionTemplateInfo, class_name, Object, kClassNameOffset)
  ACCESSORS(FunctionTemplateInfo, signature, Object, kSignatureOffset)
  ACCESSORS(FunctionTemplateInfo, instance_call_handler, Object,
            kInstanceCallHandlerOffset)
  ACCESSORS(FunctionTemplateInfo, access_check_info, Object,
            kAccessCheckInfoOffset)
  SMI_ACCESSORS(FunctionTemplateInfo, flag, kFlagOffset)
  
  ACCESSORS(ObjectTemplateInfo, constructor, Object, kConstructorOffset)
  ACCESSORS(ObjectTemplateInfo, internal_field_count, Object,
            kInternalFieldCountOffset)
  
  ACCESSORS(AllocationSite, transition_info, Object, kTransitionInfoOffset)
  ACCESSORS(AllocationSite, nested_site, Object, kNestedSiteOffset)
  SMI_ACCESSORS(AllocationSite, pretenure_data, kPretenureDataOffset)
  SMI_ACCESSORS(AllocationSite, pretenure_create_count,
                kPretenureCreateCountOffset)
  ACCESSORS(AllocationSite, dependent_code, DependentCode,
            kDependentCodeOffset)
  ACCESSORS(AllocationSite, weak_next, Object, kWeakNextOffset)
  ACCESSORS(AllocationMemento, allocation_site, Object, kAllocationSiteOffset)
  
  ACCESSORS(Script, source, Object, kSourceOffset)
  ACCESSORS(Script, name, Object, kNameOffset)
  SMI_ACCESSORS(Script, id, kIdOffset)
  SMI_ACCESSORS(Script, line_offset, kLineOffsetOffset)
  SMI_ACCESSORS(Script, column_offset, kColumnOffsetOffset)
  ACCESSORS(Script, context_data, Object, kContextOffset)
  ACCESSORS(Script, wrapper, HeapObject, kWrapperOffset)
  SMI_ACCESSORS(Script, type, kTypeOffset)
  ACCESSORS(Script, line_ends, Object, kLineEndsOffset)
  ACCESSORS(Script, eval_from_shared, Object, kEvalFromSharedOffset)
  SMI_ACCESSORS(Script, eval_from_instructions_offset,
                kEvalFrominstructionsOffsetOffset)
  ACCESSORS(Script, shared_function_infos, Object, kSharedFunctionInfosOffset)
  SMI_ACCESSORS(Script, flags, kFlagsOffset)
  ACCESSORS(Script, source_url, Object, kSourceUrlOffset)
  ACCESSORS(Script, source_mapping_url, Object, kSourceMappingUrlOffset)
  
  Script::CompilationType Script::compilation_type() {
    return BooleanBit::get(flags(), kCompilationTypeBit) ?
        COMPILATION_TYPE_EVAL : COMPILATION_TYPE_HOST;
  }
  void Script::set_compilation_type(CompilationType type) {
    set_flags(BooleanBit::set(flags(), kCompilationTypeBit,
        type == COMPILATION_TYPE_EVAL));
  }
  bool Script::hide_source() { return BooleanBit::get(flags(), kHideSourceBit); }
  void Script::set_hide_source(bool value) {
    set_flags(BooleanBit::set(flags(), kHideSourceBit, value));
  }
  Script::CompilationState Script::compilation_state() {
    return BooleanBit::get(flags(), kCompilationStateBit) ?
        COMPILATION_STATE_COMPILED : COMPILATION_STATE_INITIAL;
  }
  void Script::set_compilation_state(CompilationState state) {
    set_flags(BooleanBit::set(flags(), kCompilationStateBit,
        state == COMPILATION_STATE_COMPILED));
  }
  ScriptOriginOptions Script::origin_options() {
    return ScriptOriginOptions((flags() & kOriginOptionsMask) >>
                               kOriginOptionsShift);
  }
  void Script::set_origin_options(ScriptOriginOptions origin_options) {
    DCHECK(!(origin_options.Flags() & ~((1 << kOriginOptionsSize) - 1)));
    set_flags((flags() & ~kOriginOptionsMask) |
              (origin_options.Flags() << kOriginOptionsShift));
  }
  
  
  ACCESSORS(DebugInfo, shared, SharedFunctionInfo, kSharedFunctionInfoIndex)
  ACCESSORS(DebugInfo, abstract_code, AbstractCode, kAbstractCodeIndex)
  ACCESSORS(DebugInfo, break_points, FixedArray, kBreakPointsStateIndex)
  
  BytecodeArray* DebugInfo::original_bytecode_array() {
    return shared()->bytecode_array();
  }
  
  SMI_ACCESSORS(BreakPointInfo, code_offset, kCodeOffsetIndex)
  SMI_ACCESSORS(BreakPointInfo, source_position, kSourcePositionIndex)
  SMI_ACCESSORS(BreakPointInfo, statement_position, kStatementPositionIndex)
  ACCESSORS(BreakPointInfo, break_point_objects, Object, kBreakPointObjectsIndex)
  
  ACCESSORS(SharedFunctionInfo, name, Object, kNameOffset)
  ACCESSORS(SharedFunctionInfo, optimized_code_map, FixedArray,
            kOptimizedCodeMapOffset)
  ACCESSORS(SharedFunctionInfo, construct_stub, Code, kConstructStubOffset)
  ACCESSORS(SharedFunctionInfo, feedback_vector, TypeFeedbackVector,
            kFeedbackVectorOffset)
  #if TRACE_MAPS
  SMI_ACCESSORS(SharedFunctionInfo, unique_id, kUniqueIdOffset)
  #endif
  ACCESSORS(SharedFunctionInfo, instance_class_name, Object,
            kInstanceClassNameOffset)
  ACCESSORS(SharedFunctionInfo, function_data, Object, kFunctionDataOffset)
  ACCESSORS(SharedFunctionInfo, script, Object, kScriptOffset)
  ACCESSORS(SharedFunctionInfo, debug_info, Object, kDebugInfoOffset)
  ACCESSORS(SharedFunctionInfo, function_identifier, Object,
            kFunctionIdentifierOffset)
  
  SMI_ACCESSORS(FunctionTemplateInfo, length, kLengthOffset)
  BOOL_ACCESSORS(FunctionTemplateInfo, flag, hidden_prototype,
                 kHiddenPrototypeBit)
  BOOL_ACCESSORS(FunctionTemplateInfo, flag, undetectable, kUndetectableBit)
  BOOL_ACCESSORS(FunctionTemplateInfo, flag, needs_access_check,
                 kNeedsAccessCheckBit)
  BOOL_ACCESSORS(FunctionTemplateInfo, flag, read_only_prototype,
                 kReadOnlyPrototypeBit)
  BOOL_ACCESSORS(FunctionTemplateInfo, flag, remove_prototype,
                 kRemovePrototypeBit)
  BOOL_ACCESSORS(FunctionTemplateInfo, flag, do_not_cache,
                 kDoNotCacheBit)
  BOOL_ACCESSORS(FunctionTemplateInfo, flag, instantiated, kInstantiatedBit)
  BOOL_ACCESSORS(FunctionTemplateInfo, flag, accept_any_receiver,
                 kAcceptAnyReceiver)
  BOOL_ACCESSORS(SharedFunctionInfo, start_position_and_type, is_named_expression,
                 kIsNamedExpressionBit)
  BOOL_ACCESSORS(SharedFunctionInfo, start_position_and_type, is_toplevel,
                 kIsTopLevelBit)
  
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, allows_lazy_compilation,
                 kAllowLazyCompilation)
  BOOL_ACCESSORS(SharedFunctionInfo,
                 compiler_hints,
                 allows_lazy_compilation_without_context,
                 kAllowLazyCompilationWithoutContext)
  BOOL_ACCESSORS(SharedFunctionInfo,
                 compiler_hints,
                 uses_arguments,
                 kUsesArguments)
  BOOL_ACCESSORS(SharedFunctionInfo,
                 compiler_hints,
                 has_duplicate_parameters,
                 kHasDuplicateParameters)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, asm_function, kIsAsmFunction)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, deserialized, kDeserialized)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, never_compiled,
                 kNeverCompiled)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, is_declaration,
                 kIsDeclaration)
  
  #if V8_HOST_ARCH_32_BIT
  SMI_ACCESSORS(SharedFunctionInfo, length, kLengthOffset)
  SMI_ACCESSORS(SharedFunctionInfo, internal_formal_parameter_count,
                kFormalParameterCountOffset)
  SMI_ACCESSORS(SharedFunctionInfo, expected_nof_properties,
                kExpectedNofPropertiesOffset)
  SMI_ACCESSORS(SharedFunctionInfo, num_literals, kNumLiteralsOffset)
  SMI_ACCESSORS(SharedFunctionInfo, start_position_and_type,
                kStartPositionAndTypeOffset)
  SMI_ACCESSORS(SharedFunctionInfo, end_position, kEndPositionOffset)
  SMI_ACCESSORS(SharedFunctionInfo, function_token_position,
                kFunctionTokenPositionOffset)
  SMI_ACCESSORS(SharedFunctionInfo, compiler_hints,
                kCompilerHintsOffset)
  SMI_ACCESSORS(SharedFunctionInfo, opt_count_and_bailout_reason,
                kOptCountAndBailoutReasonOffset)
  SMI_ACCESSORS(SharedFunctionInfo, counters, kCountersOffset)
  SMI_ACCESSORS(SharedFunctionInfo, ast_node_count, kAstNodeCountOffset)
  SMI_ACCESSORS(SharedFunctionInfo, profiler_ticks, kProfilerTicksOffset)
  
  #else
  
  #if V8_TARGET_LITTLE_ENDIAN
  #define PSEUDO_SMI_LO_ALIGN 0
  #define PSEUDO_SMI_HI_ALIGN kIntSize
  #else
  #define PSEUDO_SMI_LO_ALIGN kIntSize
  #define PSEUDO_SMI_HI_ALIGN 0
  #endif
  
  #define PSEUDO_SMI_ACCESSORS_LO(holder, name, offset)                          \
    STATIC_ASSERT(holder::offset % kPointerSize == PSEUDO_SMI_LO_ALIGN);         \
    int holder::name() const {                                                   \
      int value = READ_INT_FIELD(this, offset);                                  \
      DCHECK(kHeapObjectTag == 1);                                               \
      DCHECK((value & kHeapObjectTag) == 0);                                     \
      return value >> 1;                                                         \
    }                                                                            \
    void holder::set_##name(int value) {                                         \
      DCHECK(kHeapObjectTag == 1);                                               \
      DCHECK((value & 0xC0000000) == 0xC0000000 || (value & 0xC0000000) == 0x0); \
      WRITE_INT_FIELD(this, offset, (value << 1) & ~kHeapObjectTag);             \
    }
  
  #define PSEUDO_SMI_ACCESSORS_HI(holder, name, offset)                  \
    STATIC_ASSERT(holder::offset % kPointerSize == PSEUDO_SMI_HI_ALIGN); \
    INT_ACCESSORS(holder, name, offset)
  
  
  PSEUDO_SMI_ACCESSORS_LO(SharedFunctionInfo, length, kLengthOffset)
  PSEUDO_SMI_ACCESSORS_HI(SharedFunctionInfo, internal_formal_parameter_count,
                          kFormalParameterCountOffset)
  
  PSEUDO_SMI_ACCESSORS_LO(SharedFunctionInfo,
                          expected_nof_properties,
                          kExpectedNofPropertiesOffset)
  PSEUDO_SMI_ACCESSORS_HI(SharedFunctionInfo, num_literals, kNumLiteralsOffset)
  
  PSEUDO_SMI_ACCESSORS_LO(SharedFunctionInfo, end_position, kEndPositionOffset)
  PSEUDO_SMI_ACCESSORS_HI(SharedFunctionInfo,
                          start_position_and_type,
                          kStartPositionAndTypeOffset)
  
  PSEUDO_SMI_ACCESSORS_LO(SharedFunctionInfo,
                          function_token_position,
                          kFunctionTokenPositionOffset)
  PSEUDO_SMI_ACCESSORS_HI(SharedFunctionInfo,
                          compiler_hints,
                          kCompilerHintsOffset)
  
  PSEUDO_SMI_ACCESSORS_LO(SharedFunctionInfo,
                          opt_count_and_bailout_reason,
                          kOptCountAndBailoutReasonOffset)
  PSEUDO_SMI_ACCESSORS_HI(SharedFunctionInfo, counters, kCountersOffset)
  
  PSEUDO_SMI_ACCESSORS_LO(SharedFunctionInfo,
                          ast_node_count,
                          kAstNodeCountOffset)
  PSEUDO_SMI_ACCESSORS_HI(SharedFunctionInfo,
                          profiler_ticks,
                          kProfilerTicksOffset)
  
  #endif
  
  
  BOOL_GETTER(SharedFunctionInfo,
              compiler_hints,
              optimization_disabled,
              kOptimizationDisabled)
  
  AbstractCode* SharedFunctionInfo::abstract_code() {
    if (HasBytecodeArray()) {
      return AbstractCode::cast(bytecode_array());
    } else {
      return AbstractCode::cast(code());
    }
  }
  
  void SharedFunctionInfo::set_optimization_disabled(bool disable) {
    set_compiler_hints(BooleanBit::set(compiler_hints(),
                                       kOptimizationDisabled,
                                       disable));
  }
  
  
  LanguageMode SharedFunctionInfo::language_mode() {
    STATIC_ASSERT(LANGUAGE_END == 3);
    return construct_language_mode(
        BooleanBit::get(compiler_hints(), kStrictModeFunction));
  }
  
  
  void SharedFunctionInfo::set_language_mode(LanguageMode language_mode) {
    STATIC_ASSERT(LANGUAGE_END == 3);
    // We only allow language mode transitions that set the same language mode
    // again or go up in the chain:
    DCHECK(is_sloppy(this->language_mode()) || is_strict(language_mode));
    int hints = compiler_hints();
    hints = BooleanBit::set(hints, kStrictModeFunction, is_strict(language_mode));
    set_compiler_hints(hints);
  }
  
  
  FunctionKind SharedFunctionInfo::kind() {
    return FunctionKindBits::decode(compiler_hints());
  }
  
  
  void SharedFunctionInfo::set_kind(FunctionKind kind) {
    DCHECK(IsValidFunctionKind(kind));
    int hints = compiler_hints();
    hints = FunctionKindBits::update(hints, kind);
    set_compiler_hints(hints);
  }
  
  
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, needs_home_object,
                 kNeedsHomeObject)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, native, kNative)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, force_inline, kForceInline)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints,
                 name_should_print_as_anonymous,
                 kNameShouldPrintAsAnonymous)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, is_anonymous_expression,
                 kIsAnonymousExpression)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, is_function, kIsFunction)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, dont_crankshaft,
                 kDontCrankshaft)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, dont_flush, kDontFlush)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, is_arrow, kIsArrow)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, is_generator, kIsGenerator)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, is_concise_method,
                 kIsConciseMethod)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, is_getter_function,
                 kIsGetterFunction)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, is_setter_function,
                 kIsSetterFunction)
  BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, is_default_constructor,
                 kIsDefaultConstructor)
  
  ACCESSORS(CodeCache, default_cache, FixedArray, kDefaultCacheOffset)
  ACCESSORS(CodeCache, normal_type_cache, Object, kNormalTypeCacheOffset)
  
  ACCESSORS(PolymorphicCodeCache, cache, Object, kCacheOffset)
  
  bool Script::HasValidSource() {
    Object* src = this->source();
    if (!src->IsString()) return true;
    String* src_str = String::cast(src);
    if (!StringShape(src_str).IsExternal()) return true;
    if (src_str->IsOneByteRepresentation()) {
      return ExternalOneByteString::cast(src)->resource() != NULL;
    } else if (src_str->IsTwoByteRepresentation()) {
      return ExternalTwoByteString::cast(src)->resource() != NULL;
    }
    return true;
  }
  
  
  void SharedFunctionInfo::DontAdaptArguments() {
    DCHECK(code()->kind() == Code::BUILTIN || code()->kind() == Code::STUB);
    set_internal_formal_parameter_count(kDontAdaptArgumentsSentinel);
  }
  
  
  int SharedFunctionInfo::start_position() const {
    return start_position_and_type() >> kStartPositionShift;
  }
  
  
  void SharedFunctionInfo::set_start_position(int start_position) {
    set_start_position_and_type((start_position << kStartPositionShift)
      | (start_position_and_type() & ~kStartPositionMask));
  }
  
  
  Code* SharedFunctionInfo::code() const {
    return Code::cast(READ_FIELD(this, kCodeOffset));
  }
  
  
  void SharedFunctionInfo::set_code(Code* value, WriteBarrierMode mode) {
    DCHECK(value->kind() != Code::OPTIMIZED_FUNCTION);
    WRITE_FIELD(this, kCodeOffset, value);
    CONDITIONAL_WRITE_BARRIER(value->GetHeap(), this, kCodeOffset, value, mode);
  }
  
  
  void SharedFunctionInfo::ReplaceCode(Code* value) {
    // If the GC metadata field is already used then the function was
    // enqueued as a code flushing candidate and we remove it now.
    if (code()->gc_metadata() != NULL) {
      CodeFlusher* flusher = GetHeap()->mark_compact_collector()->code_flusher();
      flusher->EvictCandidate(this);
    }
  
    DCHECK(code()->gc_metadata() == NULL && value->gc_metadata() == NULL);
  #ifdef DEBUG
    Code::VerifyRecompiledCode(code(), value);
  #endif  // DEBUG
  
    set_code(value);
  
    if (is_compiled()) set_never_compiled(false);
  }
  
  
  ScopeInfo* SharedFunctionInfo::scope_info() const {
    return reinterpret_cast<ScopeInfo*>(READ_FIELD(this, kScopeInfoOffset));
  }
  
  
  void SharedFunctionInfo::set_scope_info(ScopeInfo* value,
                                          WriteBarrierMode mode) {
    WRITE_FIELD(this, kScopeInfoOffset, reinterpret_cast<Object*>(value));
    CONDITIONAL_WRITE_BARRIER(GetHeap(),
                              this,
                              kScopeInfoOffset,
                              reinterpret_cast<Object*>(value),
                              mode);
  }
  
  
  bool SharedFunctionInfo::is_compiled() {
    Builtins* builtins = GetIsolate()->builtins();
    DCHECK(code() != builtins->builtin(Builtins::kCompileOptimizedConcurrent));
    DCHECK(code() != builtins->builtin(Builtins::kCompileOptimized));
    return code() != builtins->builtin(Builtins::kCompileLazy);
  }
  
  
  bool SharedFunctionInfo::has_simple_parameters() {
    return scope_info()->HasSimpleParameters();
  }
  
  
  bool SharedFunctionInfo::HasDebugInfo() {
    bool has_debug_info = debug_info()->IsStruct();
    DCHECK(!has_debug_info || HasDebugCode());
    return has_debug_info;
  }
  
  
  DebugInfo* SharedFunctionInfo::GetDebugInfo() {
    DCHECK(HasDebugInfo());
    return DebugInfo::cast(debug_info());
  }
  
  
  bool SharedFunctionInfo::HasDebugCode() {
    return HasBytecodeArray() ||
           (code()->kind() == Code::FUNCTION && code()->has_debug_break_slots());
  }
  
  
  bool SharedFunctionInfo::IsApiFunction() {
    return function_data()->IsFunctionTemplateInfo();
  }
  
  
  FunctionTemplateInfo* SharedFunctionInfo::get_api_func_data() {
    DCHECK(IsApiFunction());
    return FunctionTemplateInfo::cast(function_data());
  }
  
  void SharedFunctionInfo::set_api_func_data(FunctionTemplateInfo* data) {
    DCHECK(function_data()->IsUndefined());
    set_function_data(data);
  }
  
  bool SharedFunctionInfo::HasBytecodeArray() {
    return function_data()->IsBytecodeArray();
  }
  
  
  BytecodeArray* SharedFunctionInfo::bytecode_array() {
    DCHECK(HasBytecodeArray());
    return BytecodeArray::cast(function_data());
  }
  
  void SharedFunctionInfo::set_bytecode_array(BytecodeArray* bytecode) {
    DCHECK(function_data()->IsUndefined());
    set_function_data(bytecode);
  }
  
  void SharedFunctionInfo::ClearBytecodeArray() {
    DCHECK(function_data()->IsUndefined() || HasBytecodeArray());
    set_function_data(GetHeap()->undefined_value());
  }
  
  bool SharedFunctionInfo::HasBuiltinFunctionId() {
    return function_identifier()->IsSmi();
  }
  
  BuiltinFunctionId SharedFunctionInfo::builtin_function_id() {
    DCHECK(HasBuiltinFunctionId());
    return static_cast<BuiltinFunctionId>(
        Smi::cast(function_identifier())->value());
  }
  
  void SharedFunctionInfo::set_builtin_function_id(BuiltinFunctionId id) {
    set_function_identifier(Smi::FromInt(id));
  }
  
  bool SharedFunctionInfo::HasInferredName() {
    return function_identifier()->IsString();
  }
  
  String* SharedFunctionInfo::inferred_name() {
    if (HasInferredName()) {
      return String::cast(function_identifier());
    }
    DCHECK(function_identifier()->IsUndefined() || HasBuiltinFunctionId());
    return GetIsolate()->heap()->empty_string();
  }
  
  void SharedFunctionInfo::set_inferred_name(String* inferred_name) {
    DCHECK(function_identifier()->IsUndefined() || HasInferredName());
    set_function_identifier(inferred_name);
  }
  
  int SharedFunctionInfo::ic_age() {
    return ICAgeBits::decode(counters());
  }
  
  
  void SharedFunctionInfo::set_ic_age(int ic_age) {
    set_counters(ICAgeBits::update(counters(), ic_age));
  }
  
  
  int SharedFunctionInfo::deopt_count() {
    return DeoptCountBits::decode(counters());
  }
  
  
  void SharedFunctionInfo::set_deopt_count(int deopt_count) {
    set_counters(DeoptCountBits::update(counters(), deopt_count));
  }
  
  
  void SharedFunctionInfo::increment_deopt_count() {
    int value = counters();
    int deopt_count = DeoptCountBits::decode(value);
    deopt_count = (deopt_count + 1) & DeoptCountBits::kMax;
    set_counters(DeoptCountBits::update(value, deopt_count));
  }
  
  
  int SharedFunctionInfo::opt_reenable_tries() {
    return OptReenableTriesBits::decode(counters());
  }
  
  
  void SharedFunctionInfo::set_opt_reenable_tries(int tries) {
    set_counters(OptReenableTriesBits::update(counters(), tries));
  }
  
  
  int SharedFunctionInfo::opt_count() {
    return OptCountBits::decode(opt_count_and_bailout_reason());
  }
  
  
  void SharedFunctionInfo::set_opt_count(int opt_count) {
    set_opt_count_and_bailout_reason(
        OptCountBits::update(opt_count_and_bailout_reason(), opt_count));
  }
  
  
  BailoutReason SharedFunctionInfo::disable_optimization_reason() {
    return static_cast<BailoutReason>(
        DisabledOptimizationReasonBits::decode(opt_count_and_bailout_reason()));
  }
  
  
  bool SharedFunctionInfo::has_deoptimization_support() {
    Code* code = this->code();
    return code->kind() == Code::FUNCTION && code->has_deoptimization_support();
  }
  
  
  void SharedFunctionInfo::TryReenableOptimization() {
    int tries = opt_reenable_tries();
    set_opt_reenable_tries((tries + 1) & OptReenableTriesBits::kMax);
    // We reenable optimization whenever the number of tries is a large
    // enough power of 2.
    if (tries >= 16 && (((tries - 1) & tries) == 0)) {
      set_optimization_disabled(false);
      set_opt_count(0);
      set_deopt_count(0);
    }
  }
  
  
  void SharedFunctionInfo::set_disable_optimization_reason(BailoutReason reason) {
    set_opt_count_and_bailout_reason(DisabledOptimizationReasonBits::update(
        opt_count_and_bailout_reason(), reason));
  }
  
  
  bool SharedFunctionInfo::IsBuiltin() {
    Object* script_obj = script();
    if (script_obj->IsUndefined()) return true;
    Script* script = Script::cast(script_obj);
    Script::Type type = static_cast<Script::Type>(script->type());
    return type != Script::TYPE_NORMAL;
  }
  
  
  bool SharedFunctionInfo::IsSubjectToDebugging() { return !IsBuiltin(); }
  
  
  bool SharedFunctionInfo::OptimizedCodeMapIsCleared() const {
    return optimized_code_map() == GetHeap()->cleared_optimized_code_map();
  }
  
  
  bool JSFunction::IsOptimized() {
    return code()->kind() == Code::OPTIMIZED_FUNCTION;
  }
  
  
  bool JSFunction::IsMarkedForOptimization() {
    return code() == GetIsolate()->builtins()->builtin(
        Builtins::kCompileOptimized);
  }
  
  
  bool JSFunction::IsMarkedForConcurrentOptimization() {
    return code() == GetIsolate()->builtins()->builtin(
        Builtins::kCompileOptimizedConcurrent);
  }
  
  
  bool JSFunction::IsInOptimizationQueue() {
    return code() == GetIsolate()->builtins()->builtin(
        Builtins::kInOptimizationQueue);
  }
  
  
  void JSFunction::CompleteInobjectSlackTrackingIfActive() {
    if (has_initial_map() && initial_map()->IsInobjectSlackTrackingInProgress()) {
      initial_map()->CompleteInobjectSlackTracking();
    }
  }
  
  
  bool Map::IsInobjectSlackTrackingInProgress() {
    return construction_counter() != Map::kNoSlackTracking;
  }
  
  
  void Map::InobjectSlackTrackingStep() {
    if (!IsInobjectSlackTrackingInProgress()) return;
    int counter = construction_counter();
    set_construction_counter(counter - 1);
    if (counter == kSlackTrackingCounterEnd) {
      CompleteInobjectSlackTracking();
    }
  }
  
  AbstractCode* JSFunction::abstract_code() {
    Code* code = this->code();
    if (code->is_interpreter_entry_trampoline()) {
      return AbstractCode::cast(shared()->bytecode_array());
    } else {
      return AbstractCode::cast(code);
    }
  }
  
  Code* JSFunction::code() {
    return Code::cast(
        Code::GetObjectFromEntryAddress(FIELD_ADDR(this, kCodeEntryOffset)));
  }
  
  
  void JSFunction::set_code(Code* value) {
    DCHECK(!GetHeap()->InNewSpace(value));
    Address entry = value->entry();
    WRITE_INTPTR_FIELD(this, kCodeEntryOffset, reinterpret_cast<intptr_t>(entry));
    GetHeap()->incremental_marking()->RecordWriteOfCodeEntry(
        this,
        HeapObject::RawField(this, kCodeEntryOffset),
        value);
  }
  
  
  void JSFunction::set_code_no_write_barrier(Code* value) {
    DCHECK(!GetHeap()->InNewSpace(value));
    Address entry = value->entry();
    WRITE_INTPTR_FIELD(this, kCodeEntryOffset, reinterpret_cast<intptr_t>(entry));
  }
  
  
  void JSFunction::ReplaceCode(Code* code) {
    bool was_optimized = IsOptimized();
    bool is_optimized = code->kind() == Code::OPTIMIZED_FUNCTION;
  
    if (was_optimized && is_optimized) {
      shared()->EvictFromOptimizedCodeMap(this->code(),
          "Replacing with another optimized code");
    }
  
    set_code(code);
  
    // Add/remove the function from the list of optimized functions for this
    // context based on the state change.
    if (!was_optimized && is_optimized) {
      context()->native_context()->AddOptimizedFunction(this);
    }
    if (was_optimized && !is_optimized) {
      // TODO(titzer): linear in the number of optimized functions; fix!
      context()->native_context()->RemoveOptimizedFunction(this);
    }
  }
  
  
  Context* JSFunction::context() {
    return Context::cast(READ_FIELD(this, kContextOffset));
  }
  
  
  JSObject* JSFunction::global_proxy() {
    return context()->global_proxy();
  }
  
  
  Context* JSFunction::native_context() { return context()->native_context(); }
  
  
  void JSFunction::set_context(Object* value) {
    DCHECK(value->IsUndefined() || value->IsContext());
    WRITE_FIELD(this, kContextOffset, value);
    WRITE_BARRIER(GetHeap(), this, kContextOffset, value);
  }
  
  ACCESSORS(JSFunction, prototype_or_initial_map, Object,
            kPrototypeOrInitialMapOffset)
  
  
  Map* JSFunction::initial_map() {
    return Map::cast(prototype_or_initial_map());
  }
  
  
  bool JSFunction::has_initial_map() {
    return prototype_or_initial_map()->IsMap();
  }
  
  
  bool JSFunction::has_instance_prototype() {
    return has_initial_map() || !prototype_or_initial_map()->IsTheHole();
  }
  
  
  bool JSFunction::has_prototype() {
    return map()->has_non_instance_prototype() || has_instance_prototype();
  }
  
  
  Object* JSFunction::instance_prototype() {
    DCHECK(has_instance_prototype());
    if (has_initial_map()) return initial_map()->prototype();
    // When there is no initial map and the prototype is a JSObject, the
    // initial map field is used for the prototype field.
    return prototype_or_initial_map();
  }
  
  
  Object* JSFunction::prototype() {
    DCHECK(has_prototype());
    // If the function's prototype property has been set to a non-JSObject
    // value, that value is stored in the constructor field of the map.
    if (map()->has_non_instance_prototype()) {
      Object* prototype = map()->GetConstructor();
      // The map must have a prototype in that field, not a back pointer.
      DCHECK(!prototype->IsMap());
      return prototype;
    }
    return instance_prototype();
  }
  
  
  bool JSFunction::is_compiled() {
    Builtins* builtins = GetIsolate()->builtins();
    return code() != builtins->builtin(Builtins::kCompileLazy) &&
           code() != builtins->builtin(Builtins::kCompileOptimized) &&
           code() != builtins->builtin(Builtins::kCompileOptimizedConcurrent);
  }
  
  
  int JSFunction::NumberOfLiterals() {
    return literals()->length();
  }
  
  
  ACCESSORS(JSProxy, target, JSReceiver, kTargetOffset)
  ACCESSORS(JSProxy, handler, Object, kHandlerOffset)
  ACCESSORS(JSProxy, hash, Object, kHashOffset)
  
  bool JSProxy::IsRevoked() const { return !handler()->IsJSReceiver(); }
  
  ACCESSORS(JSCollection, table, Object, kTableOffset)
  
  
  #define ORDERED_HASH_TABLE_ITERATOR_ACCESSORS(name, type, offset)    \
    template<class Derived, class TableType>                           \
    type* OrderedHashTableIterator<Derived, TableType>::name() const { \
      return type::cast(READ_FIELD(this, offset));                     \
    }                                                                  \
    template<class Derived, class TableType>                           \
    void OrderedHashTableIterator<Derived, TableType>::set_##name(     \
        type* value, WriteBarrierMode mode) {                          \
      WRITE_FIELD(this, offset, value);                                \
      CONDITIONAL_WRITE_BARRIER(GetHeap(), this, offset, value, mode); \
    }
  
  ORDERED_HASH_TABLE_ITERATOR_ACCESSORS(table, Object, kTableOffset)
  ORDERED_HASH_TABLE_ITERATOR_ACCESSORS(index, Object, kIndexOffset)
  ORDERED_HASH_TABLE_ITERATOR_ACCESSORS(kind, Object, kKindOffset)
  
  #undef ORDERED_HASH_TABLE_ITERATOR_ACCESSORS
  
  
  ACCESSORS(JSWeakCollection, table, Object, kTableOffset)
  ACCESSORS(JSWeakCollection, next, Object, kNextOffset)
  
  
  Address Foreign::foreign_address() {
    return AddressFrom<Address>(READ_INTPTR_FIELD(this, kForeignAddressOffset));
  }
  
  
  void Foreign::set_foreign_address(Address value) {
    WRITE_INTPTR_FIELD(this, kForeignAddressOffset, OffsetFrom(value));
  }
  
  
  ACCESSORS(JSGeneratorObject, function, JSFunction, kFunctionOffset)
  ACCESSORS(JSGeneratorObject, context, Context, kContextOffset)
  ACCESSORS(JSGeneratorObject, receiver, Object, kReceiverOffset)
  ACCESSORS(JSGeneratorObject, input, Object, kInputOffset)
  SMI_ACCESSORS(JSGeneratorObject, continuation, kContinuationOffset)
  ACCESSORS(JSGeneratorObject, operand_stack, FixedArray, kOperandStackOffset)
  
  bool JSGeneratorObject::is_suspended() {
    DCHECK_LT(kGeneratorExecuting, kGeneratorClosed);
    DCHECK_EQ(kGeneratorClosed, 0);
    return continuation() > 0;
  }
  
  bool JSGeneratorObject::is_closed() {
    return continuation() == kGeneratorClosed;
  }
  
  bool JSGeneratorObject::is_executing() {
    return continuation() == kGeneratorExecuting;
  }
  
  ACCESSORS(JSModule, context, Object, kContextOffset)
  ACCESSORS(JSModule, scope_info, ScopeInfo, kScopeInfoOffset)
  
  
  ACCESSORS(JSValue, value, Object, kValueOffset)
  
  
  HeapNumber* HeapNumber::cast(Object* object) {
    SLOW_DCHECK(object->IsHeapNumber() || object->IsMutableHeapNumber());
    return reinterpret_cast<HeapNumber*>(object);
  }
  
  
  const HeapNumber* HeapNumber::cast(const Object* object) {
    SLOW_DCHECK(object->IsHeapNumber() || object->IsMutableHeapNumber());
    return reinterpret_cast<const HeapNumber*>(object);
  }
  
  
  ACCESSORS(JSDate, value, Object, kValueOffset)
  ACCESSORS(JSDate, cache_stamp, Object, kCacheStampOffset)
  ACCESSORS(JSDate, year, Object, kYearOffset)
  ACCESSORS(JSDate, month, Object, kMonthOffset)
  ACCESSORS(JSDate, day, Object, kDayOffset)
  ACCESSORS(JSDate, weekday, Object, kWeekdayOffset)
  ACCESSORS(JSDate, hour, Object, kHourOffset)
  ACCESSORS(JSDate, min, Object, kMinOffset)
  ACCESSORS(JSDate, sec, Object, kSecOffset)
  
  
  SMI_ACCESSORS(JSMessageObject, type, kTypeOffset)
  ACCESSORS(JSMessageObject, argument, Object, kArgumentsOffset)
  ACCESSORS(JSMessageObject, script, Object, kScriptOffset)
  ACCESSORS(JSMessageObject, stack_frames, Object, kStackFramesOffset)
  SMI_ACCESSORS(JSMessageObject, start_position, kStartPositionOffset)
  SMI_ACCESSORS(JSMessageObject, end_position, kEndPositionOffset)
  
  
  INT_ACCESSORS(Code, instruction_size, kInstructionSizeOffset)
  INT_ACCESSORS(Code, prologue_offset, kPrologueOffset)
  INT_ACCESSORS(Code, constant_pool_offset, kConstantPoolOffset)
  ACCESSORS(Code, relocation_info, ByteArray, kRelocationInfoOffset)
  ACCESSORS(Code, handler_table, FixedArray, kHandlerTableOffset)
  ACCESSORS(Code, deoptimization_data, FixedArray, kDeoptimizationDataOffset)
  ACCESSORS(Code, raw_type_feedback_info, Object, kTypeFeedbackInfoOffset)
  ACCESSORS(Code, next_code_link, Object, kNextCodeLinkOffset)
  
  
  void Code::WipeOutHeader() {
    WRITE_FIELD(this, kRelocationInfoOffset, NULL);
    WRITE_FIELD(this, kHandlerTableOffset, NULL);
    WRITE_FIELD(this, kDeoptimizationDataOffset, NULL);
    // Do not wipe out major/minor keys on a code stub or IC
    if (!READ_FIELD(this, kTypeFeedbackInfoOffset)->IsSmi()) {
      WRITE_FIELD(this, kTypeFeedbackInfoOffset, NULL);
    }
    WRITE_FIELD(this, kNextCodeLinkOffset, NULL);
    WRITE_FIELD(this, kGCMetadataOffset, NULL);
  }
  
  
  Object* Code::type_feedback_info() {
    DCHECK(kind() == FUNCTION);
    return raw_type_feedback_info();
  }
  
  
  void Code::set_type_feedback_info(Object* value, WriteBarrierMode mode) {
    DCHECK(kind() == FUNCTION);
    set_raw_type_feedback_info(value, mode);
    CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kTypeFeedbackInfoOffset,
                              value, mode);
  }
  
  
  uint32_t Code::stub_key() {
    DCHECK(IsCodeStubOrIC());
    Smi* smi_key = Smi::cast(raw_type_feedback_info());
    return static_cast<uint32_t>(smi_key->value());
  }
  
  
  void Code::set_stub_key(uint32_t key) {
    DCHECK(IsCodeStubOrIC());
    set_raw_type_feedback_info(Smi::FromInt(key));
  }
  
  
  ACCESSORS(Code, gc_metadata, Object, kGCMetadataOffset)
  INT_ACCESSORS(Code, ic_age, kICAgeOffset)
  
  
  byte* Code::instruction_start()  {
    return FIELD_ADDR(this, kHeaderSize);
  }
  
  
  byte* Code::instruction_end()  {
    return instruction_start() + instruction_size();
  }
  
  
  int Code::body_size() {
    return RoundUp(instruction_size(), kObjectAlignment);
  }
  
  
  ByteArray* Code::unchecked_relocation_info() {
    return reinterpret_cast<ByteArray*>(READ_FIELD(this, kRelocationInfoOffset));
  }
  
  
  byte* Code::relocation_start() {
    return unchecked_relocation_info()->GetDataStartAddress();
  }
  
  
  int Code::relocation_size() {
    return unchecked_relocation_info()->length();
  }
  
  
  byte* Code::entry() {
    return instruction_start();
  }
  
  
  bool Code::contains(byte* inner_pointer) {
    return (address() <= inner_pointer) && (inner_pointer <= address() + Size());
  }
  
  
  int Code::ExecutableSize() {
    // Check that the assumptions about the layout of the code object holds.
    DCHECK_EQ(static_cast<int>(instruction_start() - address()),
              Code::kHeaderSize);
    return instruction_size() + Code::kHeaderSize;
  }
  
  
  int Code::CodeSize() { return SizeFor(body_size()); }
  
  
  ACCESSORS(JSArray, length, Object, kLengthOffset)
  
  
  void* JSArrayBuffer::backing_store() const {
    intptr_t ptr = READ_INTPTR_FIELD(this, kBackingStoreOffset);
    return reinterpret_cast<void*>(ptr);
  }
  
  
  void JSArrayBuffer::set_backing_store(void* value, WriteBarrierMode mode) {
    intptr_t ptr = reinterpret_cast<intptr_t>(value);
    WRITE_INTPTR_FIELD(this, kBackingStoreOffset, ptr);
  }
  
  
  ACCESSORS(JSArrayBuffer, byte_length, Object, kByteLengthOffset)
  
  
  void JSArrayBuffer::set_bit_field(uint32_t bits) {
    if (kInt32Size != kPointerSize) {
  #if V8_TARGET_LITTLE_ENDIAN
      WRITE_UINT32_FIELD(this, kBitFieldSlot + kInt32Size, 0);
  #else
      WRITE_UINT32_FIELD(this, kBitFieldSlot, 0);
  #endif
    }
    WRITE_UINT32_FIELD(this, kBitFieldOffset, bits);
  }
  
  
  uint32_t JSArrayBuffer::bit_field() const {
    return READ_UINT32_FIELD(this, kBitFieldOffset);
  }
  
  
  bool JSArrayBuffer::is_external() { return IsExternal::decode(bit_field()); }
  
  
  void JSArrayBuffer::set_is_external(bool value) {
    set_bit_field(IsExternal::update(bit_field(), value));
  }
  
  
  bool JSArrayBuffer::is_neuterable() {
    return IsNeuterable::decode(bit_field());
  }
  
  
  void JSArrayBuffer::set_is_neuterable(bool value) {
    set_bit_field(IsNeuterable::update(bit_field(), value));
  }
  
  
  bool JSArrayBuffer::was_neutered() { return WasNeutered::decode(bit_field()); }
  
  
  void JSArrayBuffer::set_was_neutered(bool value) {
    set_bit_field(WasNeutered::update(bit_field(), value));
  }
  
  
  bool JSArrayBuffer::is_shared() { return IsShared::decode(bit_field()); }
  
  
  void JSArrayBuffer::set_is_shared(bool value) {
    set_bit_field(IsShared::update(bit_field(), value));
  }
  
  
  Object* JSArrayBufferView::byte_offset() const {
    if (WasNeutered()) return Smi::FromInt(0);
    return Object::cast(READ_FIELD(this, kByteOffsetOffset));
  }
  
  
  void JSArrayBufferView::set_byte_offset(Object* value, WriteBarrierMode mode) {
    WRITE_FIELD(this, kByteOffsetOffset, value);
    CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kByteOffsetOffset, value, mode);
  }
  
  
  Object* JSArrayBufferView::byte_length() const {
    if (WasNeutered()) return Smi::FromInt(0);
    return Object::cast(READ_FIELD(this, kByteLengthOffset));
  }
  
  
  void JSArrayBufferView::set_byte_length(Object* value, WriteBarrierMode mode) {
    WRITE_FIELD(this, kByteLengthOffset, value);
    CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kByteLengthOffset, value, mode);
  }
  
  
  ACCESSORS(JSArrayBufferView, buffer, Object, kBufferOffset)
  #ifdef VERIFY_HEAP
  ACCESSORS(JSArrayBufferView, raw_byte_offset, Object, kByteOffsetOffset)
  ACCESSORS(JSArrayBufferView, raw_byte_length, Object, kByteLengthOffset)
  #endif
  
  
  bool JSArrayBufferView::WasNeutered() const {
    return JSArrayBuffer::cast(buffer())->was_neutered();
  }
  
  
  Object* JSTypedArray::length() const {
    if (WasNeutered()) return Smi::FromInt(0);
    return Object::cast(READ_FIELD(this, kLengthOffset));
  }
  
  
  uint32_t JSTypedArray::length_value() const {
    if (WasNeutered()) return 0;
    uint32_t index = 0;
    CHECK(Object::cast(READ_FIELD(this, kLengthOffset))->ToArrayLength(&index));
    return index;
  }
  
  
  void JSTypedArray::set_length(Object* value, WriteBarrierMode mode) {
    WRITE_FIELD(this, kLengthOffset, value);
    CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kLengthOffset, value, mode);
  }
  
  
  #ifdef VERIFY_HEAP
  ACCESSORS(JSTypedArray, raw_length, Object, kLengthOffset)
  #endif
  
  
  ACCESSORS(JSRegExp, data, Object, kDataOffset)
  ACCESSORS(JSRegExp, flags, Object, kFlagsOffset)
  ACCESSORS(JSRegExp, source, Object, kSourceOffset)
  
  
  JSRegExp::Type JSRegExp::TypeTag() {
    Object* data = this->data();
    if (data->IsUndefined()) return JSRegExp::NOT_COMPILED;
    Smi* smi = Smi::cast(FixedArray::cast(data)->get(kTagIndex));
    return static_cast<JSRegExp::Type>(smi->value());
  }
  
  
  int JSRegExp::CaptureCount() {
    switch (TypeTag()) {
      case ATOM:
        return 0;
      case IRREGEXP:
        return Smi::cast(DataAt(kIrregexpCaptureCountIndex))->value();
      default:
        UNREACHABLE();
        return -1;
    }
  }
  
  
  JSRegExp::Flags JSRegExp::GetFlags() {
    DCHECK(this->data()->IsFixedArray());
    Object* data = this->data();
    Smi* smi = Smi::cast(FixedArray::cast(data)->get(kFlagsIndex));
    return Flags(smi->value());
  }
  
  
  String* JSRegExp::Pattern() {
    DCHECK(this->data()->IsFixedArray());
    Object* data = this->data();
    String* pattern = String::cast(FixedArray::cast(data)->get(kSourceIndex));
    return pattern;
  }
  
  
  Object* JSRegExp::DataAt(int index) {
    DCHECK(TypeTag() != NOT_COMPILED);
    return FixedArray::cast(data())->get(index);
  }
  
  
  void JSRegExp::SetDataAt(int index, Object* value) {
    DCHECK(TypeTag() != NOT_COMPILED);
    DCHECK(index >= kDataIndex);  // Only implementation data can be set this way.
    FixedArray::cast(data())->set(index, value);
  }
  
  
  ElementsKind JSObject::GetElementsKind() {
    ElementsKind kind = map()->elements_kind();
  #if VERIFY_HEAP && DEBUG
    FixedArrayBase* fixed_array =
        reinterpret_cast<FixedArrayBase*>(READ_FIELD(this, kElementsOffset));
  
    // If a GC was caused while constructing this object, the elements
    // pointer may point to a one pointer filler map.
    if (ElementsAreSafeToExamine()) {
      Map* map = fixed_array->map();
      DCHECK((IsFastSmiOrObjectElementsKind(kind) &&
              (map == GetHeap()->fixed_array_map() ||
               map == GetHeap()->fixed_cow_array_map())) ||
             (IsFastDoubleElementsKind(kind) &&
              (fixed_array->IsFixedDoubleArray() ||
               fixed_array == GetHeap()->empty_fixed_array())) ||
             (kind == DICTIONARY_ELEMENTS &&
              fixed_array->IsFixedArray() &&
              fixed_array->IsDictionary()) ||
             (kind > DICTIONARY_ELEMENTS));
      DCHECK(!IsSloppyArgumentsElements(kind) ||
             (elements()->IsFixedArray() && elements()->length() >= 2));
    }
  #endif
    return kind;
  }
  
  
  bool JSObject::HasFastObjectElements() {
    return IsFastObjectElementsKind(GetElementsKind());
  }
  
  
  bool JSObject::HasFastSmiElements() {
    return IsFastSmiElementsKind(GetElementsKind());
  }
  
  
  bool JSObject::HasFastSmiOrObjectElements() {
    return IsFastSmiOrObjectElementsKind(GetElementsKind());
  }
  
  
  bool JSObject::HasFastDoubleElements() {
    return IsFastDoubleElementsKind(GetElementsKind());
  }
  
  
  bool JSObject::HasFastHoleyElements() {
    return IsFastHoleyElementsKind(GetElementsKind());
  }
  
  
  bool JSObject::HasFastElements() {
    return IsFastElementsKind(GetElementsKind());
  }
  
  
  bool JSObject::HasDictionaryElements() {
    return GetElementsKind() == DICTIONARY_ELEMENTS;
  }
  
  
  bool JSObject::HasFastArgumentsElements() {
    return GetElementsKind() == FAST_SLOPPY_ARGUMENTS_ELEMENTS;
  }
  
  
  bool JSObject::HasSlowArgumentsElements() {
    return GetElementsKind() == SLOW_SLOPPY_ARGUMENTS_ELEMENTS;
  }
  
  
  bool JSObject::HasSloppyArgumentsElements() {
    return IsSloppyArgumentsElements(GetElementsKind());
  }
  
  bool JSObject::HasStringWrapperElements() {
    return IsStringWrapperElementsKind(GetElementsKind());
  }
  
  bool JSObject::HasFastStringWrapperElements() {
    return GetElementsKind() == FAST_STRING_WRAPPER_ELEMENTS;
  }
  
  bool JSObject::HasSlowStringWrapperElements() {
    return GetElementsKind() == SLOW_STRING_WRAPPER_ELEMENTS;
  }
  
  bool JSObject::HasFixedTypedArrayElements() {
    DCHECK_NOT_NULL(elements());
    return map()->has_fixed_typed_array_elements();
  }
  
  #define FIXED_TYPED_ELEMENTS_CHECK(Type, type, TYPE, ctype, size)      \
    bool JSObject::HasFixed##Type##Elements() {                          \
      HeapObject* array = elements();                                    \
      DCHECK(array != NULL);                                             \
      if (!array->IsHeapObject()) return false;                          \
      return array->map()->instance_type() == FIXED_##TYPE##_ARRAY_TYPE; \
    }
  
  TYPED_ARRAYS(FIXED_TYPED_ELEMENTS_CHECK)
  
  #undef FIXED_TYPED_ELEMENTS_CHECK
  
  
  bool JSObject::HasNamedInterceptor() {
    return map()->has_named_interceptor();
  }
  
  
  bool JSObject::HasIndexedInterceptor() {
    return map()->has_indexed_interceptor();
  }
  
  
  GlobalDictionary* JSObject::global_dictionary() {
    DCHECK(!HasFastProperties());
    DCHECK(IsJSGlobalObject());
    return GlobalDictionary::cast(properties());
  }
  
  
  SeededNumberDictionary* JSObject::element_dictionary() {
    DCHECK(HasDictionaryElements() || HasSlowStringWrapperElements());
    return SeededNumberDictionary::cast(elements());
  }
  
  
  bool Name::IsHashFieldComputed(uint32_t field) {
    return (field & kHashNotComputedMask) == 0;
  }
  
  
  bool Name::HasHashCode() {
    return IsHashFieldComputed(hash_field());
  }
  
  
  uint32_t Name::Hash() {
    // Fast case: has hash code already been computed?
    uint32_t field = hash_field();
    if (IsHashFieldComputed(field)) return field >> kHashShift;
    // Slow case: compute hash code and set it. Has to be a string.
    return String::cast(this)->ComputeAndSetHash();
  }
  
  
  bool Name::IsPrivate() {
    return this->IsSymbol() && Symbol::cast(this)->is_private();
  }
  
  
  StringHasher::StringHasher(int length, uint32_t seed)
    : length_(length),
      raw_running_hash_(seed),
      array_index_(0),
      is_array_index_(0 < length_ && length_ <= String::kMaxArrayIndexSize),
      is_first_char_(true) {
    DCHECK(FLAG_randomize_hashes || raw_running_hash_ == 0);
  }
  
  
  bool StringHasher::has_trivial_hash() {
    return length_ > String::kMaxHashCalcLength;
  }
  
  
  uint32_t StringHasher::AddCharacterCore(uint32_t running_hash, uint16_t c) {
    running_hash += c;
    running_hash += (running_hash << 10);
    running_hash ^= (running_hash >> 6);
    return running_hash;
  }
  
  
  uint32_t StringHasher::GetHashCore(uint32_t running_hash) {
    running_hash += (running_hash << 3);
    running_hash ^= (running_hash >> 11);
    running_hash += (running_hash << 15);
    if ((running_hash & String::kHashBitMask) == 0) {
      return kZeroHash;
    }
    return running_hash;
  }
  
  
  uint32_t StringHasher::ComputeRunningHash(uint32_t running_hash,
                                            const uc16* chars, int length) {
    DCHECK_NOT_NULL(chars);
    DCHECK(length >= 0);
    for (int i = 0; i < length; ++i) {
      running_hash = AddCharacterCore(running_hash, *chars++);
    }
    return running_hash;
  }
  
  
  uint32_t StringHasher::ComputeRunningHashOneByte(uint32_t running_hash,
                                                   const char* chars,
                                                   int length) {
    DCHECK_NOT_NULL(chars);
    DCHECK(length >= 0);
    for (int i = 0; i < length; ++i) {
      uint16_t c = static_cast<uint16_t>(*chars++);
      running_hash = AddCharacterCore(running_hash, c);
    }
    return running_hash;
  }
  
  
  void StringHasher::AddCharacter(uint16_t c) {
    // Use the Jenkins one-at-a-time hash function to update the hash
    // for the given character.
    raw_running_hash_ = AddCharacterCore(raw_running_hash_, c);
  }
  
  
  bool StringHasher::UpdateIndex(uint16_t c) {
    DCHECK(is_array_index_);
    if (c < '0' || c > '9') {
      is_array_index_ = false;
      return false;
    }
    int d = c - '0';
    if (is_first_char_) {
      is_first_char_ = false;
      if (c == '0' && length_ > 1) {
        is_array_index_ = false;
        return false;
      }
    }
    if (array_index_ > 429496729U - ((d + 3) >> 3)) {
      is_array_index_ = false;
      return false;
    }
    array_index_ = array_index_ * 10 + d;
    return true;
  }
  
  
  template<typename Char>
  inline void StringHasher::AddCharacters(const Char* chars, int length) {
    DCHECK(sizeof(Char) == 1 || sizeof(Char) == 2);
    int i = 0;
    if (is_array_index_) {
      for (; i < length; i++) {
        AddCharacter(chars[i]);
        if (!UpdateIndex(chars[i])) {
          i++;
          break;
        }
      }
    }
    for (; i < length; i++) {
      DCHECK(!is_array_index_);
      AddCharacter(chars[i]);
    }
  }
  
  
  template <typename schar>
  uint32_t StringHasher::HashSequentialString(const schar* chars,
                                              int length,
                                              uint32_t seed) {
    StringHasher hasher(length, seed);
    if (!hasher.has_trivial_hash()) hasher.AddCharacters(chars, length);
    return hasher.GetHashField();
  }
  
  
  IteratingStringHasher::IteratingStringHasher(int len, uint32_t seed)
      : StringHasher(len, seed) {}
  
  
  uint32_t IteratingStringHasher::Hash(String* string, uint32_t seed) {
    IteratingStringHasher hasher(string->length(), seed);
    // Nothing to do.
    if (hasher.has_trivial_hash()) return hasher.GetHashField();
    ConsString* cons_string = String::VisitFlat(&hasher, string);
    if (cons_string == nullptr) return hasher.GetHashField();
    hasher.VisitConsString(cons_string);
    return hasher.GetHashField();
  }
  
  
  void IteratingStringHasher::VisitOneByteString(const uint8_t* chars,
                                                 int length) {
    AddCharacters(chars, length);
  }
  
  
  void IteratingStringHasher::VisitTwoByteString(const uint16_t* chars,
                                                 int length) {
    AddCharacters(chars, length);
  }
  
  
  bool Name::AsArrayIndex(uint32_t* index) {
    return IsString() && String::cast(this)->AsArrayIndex(index);
  }
  
  
  bool String::AsArrayIndex(uint32_t* index) {
    uint32_t field = hash_field();
    if (IsHashFieldComputed(field) && (field & kIsNotArrayIndexMask)) {
      return false;
    }
    return SlowAsArrayIndex(index);
  }
  
  
  void String::SetForwardedInternalizedString(String* canonical) {
    DCHECK(IsInternalizedString());
    DCHECK(HasHashCode());
    if (canonical == this) return;  // No need to forward.
    DCHECK(SlowEquals(canonical));
    DCHECK(canonical->IsInternalizedString());
    DCHECK(canonical->HasHashCode());
    WRITE_FIELD(this, kHashFieldSlot, canonical);
    // Setting the hash field to a tagged value sets the LSB, causing the hash
    // code to be interpreted as uninitialized.  We use this fact to recognize
    // that we have a forwarded string.
    DCHECK(!HasHashCode());
  }
  
  
  String* String::GetForwardedInternalizedString() {
    DCHECK(IsInternalizedString());
    if (HasHashCode()) return this;
    String* canonical = String::cast(READ_FIELD(this, kHashFieldSlot));
    DCHECK(canonical->IsInternalizedString());
    DCHECK(SlowEquals(canonical));
    DCHECK(canonical->HasHashCode());
    return canonical;
  }
  
  
  // static
  Maybe<bool> Object::GreaterThan(Handle<Object> x, Handle<Object> y) {
    Maybe<ComparisonResult> result = Compare(x, y);
    if (result.IsJust()) {
      switch (result.FromJust()) {
        case ComparisonResult::kGreaterThan:
          return Just(true);
        case ComparisonResult::kLessThan:
        case ComparisonResult::kEqual:
        case ComparisonResult::kUndefined:
          return Just(false);
      }
    }
    return Nothing<bool>();
  }
  
  
  // static
  Maybe<bool> Object::GreaterThanOrEqual(Handle<Object> x, Handle<Object> y) {
    Maybe<ComparisonResult> result = Compare(x, y);
    if (result.IsJust()) {
      switch (result.FromJust()) {
        case ComparisonResult::kEqual:
        case ComparisonResult::kGreaterThan:
          return Just(true);
        case ComparisonResult::kLessThan:
        case ComparisonResult::kUndefined:
          return Just(false);
      }
    }
    return Nothing<bool>();
  }
  
  
  // static
  Maybe<bool> Object::LessThan(Handle<Object> x, Handle<Object> y) {
    Maybe<ComparisonResult> result = Compare(x, y);
    if (result.IsJust()) {
      switch (result.FromJust()) {
        case ComparisonResult::kLessThan:
          return Just(true);
        case ComparisonResult::kEqual:
        case ComparisonResult::kGreaterThan:
        case ComparisonResult::kUndefined:
          return Just(false);
      }
    }
    return Nothing<bool>();
  }
  
  
  // static
  Maybe<bool> Object::LessThanOrEqual(Handle<Object> x, Handle<Object> y) {
    Maybe<ComparisonResult> result = Compare(x, y);
    if (result.IsJust()) {
      switch (result.FromJust()) {
        case ComparisonResult::kEqual:
        case ComparisonResult::kLessThan:
          return Just(true);
        case ComparisonResult::kGreaterThan:
        case ComparisonResult::kUndefined:
          return Just(false);
      }
    }
    return Nothing<bool>();
  }
  
  MaybeHandle<Object> Object::GetPropertyOrElement(Handle<Object> object,
                                                   Handle<Name> name) {
    LookupIterator it =
        LookupIterator::PropertyOrElement(name->GetIsolate(), object, name);
    return GetProperty(&it);
  }
  
  MaybeHandle<Object> Object::SetPropertyOrElement(Handle<Object> object,
                                                   Handle<Name> name,
                                                   Handle<Object> value,
                                                   LanguageMode language_mode,
                                                   StoreFromKeyed store_mode) {
    LookupIterator it =
        LookupIterator::PropertyOrElement(name->GetIsolate(), object, name);
    MAYBE_RETURN_NULL(SetProperty(&it, value, language_mode, store_mode));
    return value;
  }
  
  MaybeHandle<Object> Object::GetPropertyOrElement(Handle<Object> receiver,
                                                   Handle<Name> name,
                                                   Handle<JSReceiver> holder) {
    LookupIterator it = LookupIterator::PropertyOrElement(
        name->GetIsolate(), receiver, name, holder);
    return GetProperty(&it);
  }
  
  
  void JSReceiver::initialize_properties() {
    DCHECK(!GetHeap()->InNewSpace(GetHeap()->empty_fixed_array()));
    DCHECK(!GetHeap()->InNewSpace(GetHeap()->empty_properties_dictionary()));
    if (map()->is_dictionary_map()) {
      WRITE_FIELD(this, kPropertiesOffset,
                  GetHeap()->empty_properties_dictionary());
    } else {
      WRITE_FIELD(this, kPropertiesOffset, GetHeap()->empty_fixed_array());
    }
  }
  
  
  bool JSReceiver::HasFastProperties() {
    DCHECK(properties()->IsDictionary() == map()->is_dictionary_map());
    return !properties()->IsDictionary();
  }
  
  
  NameDictionary* JSReceiver::property_dictionary() {
    DCHECK(!HasFastProperties());
    DCHECK(!IsJSGlobalObject());
    return NameDictionary::cast(properties());
  }
  
  Maybe<bool> JSReceiver::HasProperty(Handle<JSReceiver> object,
                                      Handle<Name> name) {
    LookupIterator it = LookupIterator::PropertyOrElement(object->GetIsolate(),
                                                          object, name, object);
    return HasProperty(&it);
  }
  
  
  Maybe<bool> JSReceiver::HasOwnProperty(Handle<JSReceiver> object,
                                         Handle<Name> name) {
    if (object->IsJSObject()) {  // Shortcut
      LookupIterator it = LookupIterator::PropertyOrElement(
          object->GetIsolate(), object, name, object, LookupIterator::HIDDEN);
      return HasProperty(&it);
    }
  
    Maybe<PropertyAttributes> attributes =
        JSReceiver::GetOwnPropertyAttributes(object, name);
    MAYBE_RETURN(attributes, Nothing<bool>());
    return Just(attributes.FromJust() != ABSENT);
  }
  
  
  Maybe<PropertyAttributes> JSReceiver::GetPropertyAttributes(
      Handle<JSReceiver> object, Handle<Name> name) {
    LookupIterator it = LookupIterator::PropertyOrElement(name->GetIsolate(),
                                                          object, name, object);
    return GetPropertyAttributes(&it);
  }
  
  
  Maybe<PropertyAttributes> JSReceiver::GetOwnPropertyAttributes(
      Handle<JSReceiver> object, Handle<Name> name) {
    LookupIterator it = LookupIterator::PropertyOrElement(
        name->GetIsolate(), object, name, object, LookupIterator::HIDDEN);
    return GetPropertyAttributes(&it);
  }
  
  
  Maybe<bool> JSReceiver::HasElement(Handle<JSReceiver> object, uint32_t index) {
    LookupIterator it(object->GetIsolate(), object, index, object);
    return HasProperty(&it);
  }
  
  
  Maybe<PropertyAttributes> JSReceiver::GetElementAttributes(
      Handle<JSReceiver> object, uint32_t index) {
    Isolate* isolate = object->GetIsolate();
    LookupIterator it(isolate, object, index, object);
    return GetPropertyAttributes(&it);
  }
  
  
  Maybe<PropertyAttributes> JSReceiver::GetOwnElementAttributes(
      Handle<JSReceiver> object, uint32_t index) {
    Isolate* isolate = object->GetIsolate();
    LookupIterator it(isolate, object, index, object, LookupIterator::HIDDEN);
    return GetPropertyAttributes(&it);
  }
  
  
  bool JSGlobalObject::IsDetached() {
    return JSGlobalProxy::cast(global_proxy())->IsDetachedFrom(this);
  }
  
  
  bool JSGlobalProxy::IsDetachedFrom(JSGlobalObject* global) const {
    const PrototypeIterator iter(this->GetIsolate(),
                                 const_cast<JSGlobalProxy*>(this));
    return iter.GetCurrent() != global;
  }
  
  
  Handle<Smi> JSReceiver::GetOrCreateIdentityHash(Handle<JSReceiver> object) {
    return object->IsJSProxy()
        ? JSProxy::GetOrCreateIdentityHash(Handle<JSProxy>::cast(object))
        : JSObject::GetOrCreateIdentityHash(Handle<JSObject>::cast(object));
  }
  
  Handle<Object> JSReceiver::GetIdentityHash(Isolate* isolate,
                                             Handle<JSReceiver> receiver) {
    return receiver->IsJSProxy() ? JSProxy::GetIdentityHash(
                                       isolate, Handle<JSProxy>::cast(receiver))
                                 : JSObject::GetIdentityHash(
                                       isolate, Handle<JSObject>::cast(receiver));
  }
  
  
  bool AccessorInfo::all_can_read() {
    return BooleanBit::get(flag(), kAllCanReadBit);
  }
  
  
  void AccessorInfo::set_all_can_read(bool value) {
    set_flag(BooleanBit::set(flag(), kAllCanReadBit, value));
  }
  
  
  bool AccessorInfo::all_can_write() {
    return BooleanBit::get(flag(), kAllCanWriteBit);
  }
  
  
  void AccessorInfo::set_all_can_write(bool value) {
    set_flag(BooleanBit::set(flag(), kAllCanWriteBit, value));
  }
  
  
  bool AccessorInfo::is_special_data_property() {
    return BooleanBit::get(flag(), kSpecialDataProperty);
  }
  
  
  void AccessorInfo::set_is_special_data_property(bool value) {
    set_flag(BooleanBit::set(flag(), kSpecialDataProperty, value));
  }
  
  bool AccessorInfo::is_sloppy() { return BooleanBit::get(flag(), kIsSloppy); }
  
  void AccessorInfo::set_is_sloppy(bool value) {
    set_flag(BooleanBit::set(flag(), kIsSloppy, value));
  }
  
  PropertyAttributes AccessorInfo::property_attributes() {
    return AttributesField::decode(static_cast<uint32_t>(flag()));
  }
  
  
  void AccessorInfo::set_property_attributes(PropertyAttributes attributes) {
    set_flag(AttributesField::update(flag(), attributes));
  }
  
  
  bool AccessorInfo::IsCompatibleReceiver(Object* receiver) {
    if (!HasExpectedReceiverType()) return true;
    if (!receiver->IsJSObject()) return false;
    return FunctionTemplateInfo::cast(expected_receiver_type())
        ->IsTemplateFor(JSObject::cast(receiver)->map());
  }
  
  
  bool AccessorInfo::HasExpectedReceiverType() {
    return expected_receiver_type()->IsFunctionTemplateInfo();
  }
  
  
  Object* AccessorPair::get(AccessorComponent component) {
    return component == ACCESSOR_GETTER ? getter() : setter();
  }
  
  
  void AccessorPair::set(AccessorComponent component, Object* value) {
    if (component == ACCESSOR_GETTER) {
      set_getter(value);
    } else {
      set_setter(value);
    }
  }
  
  
  void AccessorPair::SetComponents(Object* getter, Object* setter) {
    if (!getter->IsNull()) set_getter(getter);
    if (!setter->IsNull()) set_setter(setter);
  }
  
  
  bool AccessorPair::Equals(AccessorPair* pair) {
    return (this == pair) || pair->Equals(getter(), setter());
  }
  
  
  bool AccessorPair::Equals(Object* getter_value, Object* setter_value) {
    return (getter() == getter_value) && (setter() == setter_value);
  }
  
  
  bool AccessorPair::ContainsAccessor() {
    return IsJSAccessor(getter()) || IsJSAccessor(setter());
  }
  
  
  bool AccessorPair::IsJSAccessor(Object* obj) {
    return obj->IsCallable() || obj->IsUndefined();
  }
  
  
  template<typename Derived, typename Shape, typename Key>
  void Dictionary<Derived, Shape, Key>::SetEntry(int entry,
                                                 Handle<Object> key,
                                                 Handle<Object> value) {
    this->SetEntry(entry, key, value, PropertyDetails(Smi::FromInt(0)));
  }
  
  
  template<typename Derived, typename Shape, typename Key>
  void Dictionary<Derived, Shape, Key>::SetEntry(int entry,
                                                 Handle<Object> key,
                                                 Handle<Object> value,
                                                 PropertyDetails details) {
    Shape::SetEntry(static_cast<Derived*>(this), entry, key, value, details);
  }
  
  
  template <typename Key>
  template <typename Dictionary>
  void BaseDictionaryShape<Key>::SetEntry(Dictionary* dict, int entry,
                                          Handle<Object> key,
                                          Handle<Object> value,
                                          PropertyDetails details) {
    STATIC_ASSERT(Dictionary::kEntrySize == 3);
    DCHECK(!key->IsName() || details.dictionary_index() > 0);
    int index = dict->EntryToIndex(entry);
    DisallowHeapAllocation no_gc;
    WriteBarrierMode mode = dict->GetWriteBarrierMode(no_gc);
    dict->set(index, *key, mode);
    dict->set(index + 1, *value, mode);
    dict->set(index + 2, details.AsSmi());
  }
  
  
  template <typename Dictionary>
  void GlobalDictionaryShape::SetEntry(Dictionary* dict, int entry,
                                       Handle<Object> key, Handle<Object> value,
                                       PropertyDetails details) {
    STATIC_ASSERT(Dictionary::kEntrySize == 2);
    DCHECK(!key->IsName() || details.dictionary_index() > 0);
    DCHECK(value->IsPropertyCell());
    int index = dict->EntryToIndex(entry);
    DisallowHeapAllocation no_gc;
    WriteBarrierMode mode = dict->GetWriteBarrierMode(no_gc);
    dict->set(index, *key, mode);
    dict->set(index + 1, *value, mode);
    PropertyCell::cast(*value)->set_property_details(details);
  }
  
  
  bool NumberDictionaryShape::IsMatch(uint32_t key, Object* other) {
    DCHECK(other->IsNumber());
    return key == static_cast<uint32_t>(other->Number());
  }
  
  
  uint32_t UnseededNumberDictionaryShape::Hash(uint32_t key) {
    return ComputeIntegerHash(key, 0);
  }
  
  
  uint32_t UnseededNumberDictionaryShape::HashForObject(uint32_t key,
                                                        Object* other) {
    DCHECK(other->IsNumber());
    return ComputeIntegerHash(static_cast<uint32_t>(other->Number()), 0);
  }
  
  
  uint32_t SeededNumberDictionaryShape::SeededHash(uint32_t key, uint32_t seed) {
    return ComputeIntegerHash(key, seed);
  }
  
  
  uint32_t SeededNumberDictionaryShape::SeededHashForObject(uint32_t key,
                                                            uint32_t seed,
                                                            Object* other) {
    DCHECK(other->IsNumber());
    return ComputeIntegerHash(static_cast<uint32_t>(other->Number()), seed);
  }
  
  
  Handle<Object> NumberDictionaryShape::AsHandle(Isolate* isolate, uint32_t key) {
    return isolate->factory()->NewNumberFromUint(key);
  }
  
  
  bool NameDictionaryShape::IsMatch(Handle<Name> key, Object* other) {
    // We know that all entries in a hash table had their hash keys created.
    // Use that knowledge to have fast failure.
    if (key->Hash() != Name::cast(other)->Hash()) return false;
    return key->Equals(Name::cast(other));
  }
  
  
  uint32_t NameDictionaryShape::Hash(Handle<Name> key) {
    return key->Hash();
  }
  
  
  uint32_t NameDictionaryShape::HashForObject(Handle<Name> key, Object* other) {
    return Name::cast(other)->Hash();
  }
  
  
  Handle<Object> NameDictionaryShape::AsHandle(Isolate* isolate,
                                               Handle<Name> key) {
    DCHECK(key->IsUniqueName());
    return key;
  }
  
  
  Handle<FixedArray> NameDictionary::DoGenerateNewEnumerationIndices(
      Handle<NameDictionary> dictionary) {
    return DerivedDictionary::GenerateNewEnumerationIndices(dictionary);
  }
  
  
  template <typename Dictionary>
  PropertyDetails GlobalDictionaryShape::DetailsAt(Dictionary* dict, int entry) {
    DCHECK(entry >= 0);  // Not found is -1, which is not caught by get().
    Object* raw_value = dict->ValueAt(entry);
    DCHECK(raw_value->IsPropertyCell());
    PropertyCell* cell = PropertyCell::cast(raw_value);
    return cell->property_details();
  }
  
  
  template <typename Dictionary>
  void GlobalDictionaryShape::DetailsAtPut(Dictionary* dict, int entry,
                                           PropertyDetails value) {
    DCHECK(entry >= 0);  // Not found is -1, which is not caught by get().
    Object* raw_value = dict->ValueAt(entry);
    DCHECK(raw_value->IsPropertyCell());
    PropertyCell* cell = PropertyCell::cast(raw_value);
    cell->set_property_details(value);
  }
  
  
  template <typename Dictionary>
  bool GlobalDictionaryShape::IsDeleted(Dictionary* dict, int entry) {
    DCHECK(dict->ValueAt(entry)->IsPropertyCell());
    return PropertyCell::cast(dict->ValueAt(entry))->value()->IsTheHole();
  }
  
  
  bool ObjectHashTableShape::IsMatch(Handle<Object> key, Object* other) {
    return key->SameValue(other);
  }
  
  
  uint32_t ObjectHashTableShape::Hash(Handle<Object> key) {
    return Smi::cast(key->GetHash())->value();
  }
  
  
  uint32_t ObjectHashTableShape::HashForObject(Handle<Object> key,
                                               Object* other) {
    return Smi::cast(other->GetHash())->value();
  }
  
  
  Handle<Object> ObjectHashTableShape::AsHandle(Isolate* isolate,
                                                Handle<Object> key) {
    return key;
  }
  
  
  Handle<ObjectHashTable> ObjectHashTable::Shrink(
      Handle<ObjectHashTable> table, Handle<Object> key) {
    return DerivedHashTable::Shrink(table, key);
  }
  
  
  Object* OrderedHashMap::ValueAt(int entry) {
    return get(EntryToIndex(entry) + kValueOffset);
  }
  
  
  template <int entrysize>
  bool WeakHashTableShape<entrysize>::IsMatch(Handle<Object> key, Object* other) {
    if (other->IsWeakCell()) other = WeakCell::cast(other)->value();
    return key->IsWeakCell() ? WeakCell::cast(*key)->value() == other
                             : *key == other;
  }
  
  
  template <int entrysize>
  uint32_t WeakHashTableShape<entrysize>::Hash(Handle<Object> key) {
    intptr_t hash =
        key->IsWeakCell()
            ? reinterpret_cast<intptr_t>(WeakCell::cast(*key)->value())
            : reinterpret_cast<intptr_t>(*key);
    return (uint32_t)(hash & 0xFFFFFFFF);
  }
  
  
  template <int entrysize>
  uint32_t WeakHashTableShape<entrysize>::HashForObject(Handle<Object> key,
                                                        Object* other) {
    if (other->IsWeakCell()) other = WeakCell::cast(other)->value();
    intptr_t hash = reinterpret_cast<intptr_t>(other);
    return (uint32_t)(hash & 0xFFFFFFFF);
  }
  
  
  template <int entrysize>
  Handle<Object> WeakHashTableShape<entrysize>::AsHandle(Isolate* isolate,
                                                         Handle<Object> key) {
    return key;
  }
  
  
  bool ScopeInfo::IsAsmModule() { return AsmModuleField::decode(Flags()); }
  
  
  bool ScopeInfo::IsAsmFunction() { return AsmFunctionField::decode(Flags()); }
  
  
  bool ScopeInfo::HasSimpleParameters() {
    return HasSimpleParametersField::decode(Flags());
  }
  
  
  #define SCOPE_INFO_FIELD_ACCESSORS(name)                                      \
    void ScopeInfo::Set##name(int value) { set(k##name, Smi::FromInt(value)); } \
    int ScopeInfo::name() {                                                     \
      if (length() > 0) {                                                       \
        return Smi::cast(get(k##name))->value();                                \
      } else {                                                                  \
        return 0;                                                               \
      }                                                                         \
    }
  FOR_EACH_SCOPE_INFO_NUMERIC_FIELD(SCOPE_INFO_FIELD_ACCESSORS)
  #undef SCOPE_INFO_FIELD_ACCESSORS
  
  
  void Map::ClearCodeCache(Heap* heap) {
    // No write barrier is needed since empty_fixed_array is not in new space.
    // Please note this function is used during marking:
    //  - MarkCompactCollector::MarkUnmarkedObject
    //  - IncrementalMarking::Step
    DCHECK(!heap->InNewSpace(heap->empty_fixed_array()));
    WRITE_FIELD(this, kCodeCacheOffset, heap->empty_fixed_array());
  }
  
  
  int Map::SlackForArraySize(int old_size, int size_limit) {
    const int max_slack = size_limit - old_size;
    CHECK_LE(0, max_slack);
    if (old_size < 4) {
      DCHECK_LE(1, max_slack);
      return 1;
    }
    return Min(max_slack, old_size / 4);
  }
  
  
  void JSArray::set_length(Smi* length) {
    // Don't need a write barrier for a Smi.
    set_length(static_cast<Object*>(length), SKIP_WRITE_BARRIER);
  }
  
  
  bool JSArray::SetLengthWouldNormalize(Heap* heap, uint32_t new_length) {
    // If the new array won't fit in a some non-trivial fraction of the max old
    // space size, then force it to go dictionary mode.
    uint32_t max_fast_array_size =
        static_cast<uint32_t>((heap->MaxOldGenerationSize() / kDoubleSize) / 4);
    return new_length >= max_fast_array_size;
  }
  
  
  bool JSArray::AllowsSetLength() {
    bool result = elements()->IsFixedArray() || elements()->IsFixedDoubleArray();
    DCHECK(result == !HasFixedTypedArrayElements());
    return result;
  }
  
  
  void JSArray::SetContent(Handle<JSArray> array,
                           Handle<FixedArrayBase> storage) {
    EnsureCanContainElements(array, storage, storage->length(),
                             ALLOW_COPIED_DOUBLE_ELEMENTS);
  
    DCHECK((storage->map() == array->GetHeap()->fixed_double_array_map() &&
            IsFastDoubleElementsKind(array->GetElementsKind())) ||
           ((storage->map() != array->GetHeap()->fixed_double_array_map()) &&
            (IsFastObjectElementsKind(array->GetElementsKind()) ||
             (IsFastSmiElementsKind(array->GetElementsKind()) &&
              Handle<FixedArray>::cast(storage)->ContainsOnlySmisOrHoles()))));
    array->set_elements(*storage);
    array->set_length(Smi::FromInt(storage->length()));
  }
  
  
  bool JSArray::HasArrayPrototype(Isolate* isolate) {
    return map()->prototype() == *isolate->initial_array_prototype();
  }
  
  
  int TypeFeedbackInfo::ic_total_count() {
    int current = Smi::cast(READ_FIELD(this, kStorage1Offset))->value();
    return ICTotalCountField::decode(current);
  }
  
  
  void TypeFeedbackInfo::set_ic_total_count(int count) {
    int value = Smi::cast(READ_FIELD(this, kStorage1Offset))->value();
    value = ICTotalCountField::update(value,
                                      ICTotalCountField::decode(count));
    WRITE_FIELD(this, kStorage1Offset, Smi::FromInt(value));
  }
  
  
  int TypeFeedbackInfo::ic_with_type_info_count() {
    int current = Smi::cast(READ_FIELD(this, kStorage2Offset))->value();
    return ICsWithTypeInfoCountField::decode(current);
  }
  
  
  void TypeFeedbackInfo::change_ic_with_type_info_count(int delta) {
    if (delta == 0) return;
    int value = Smi::cast(READ_FIELD(this, kStorage2Offset))->value();
    int new_count = ICsWithTypeInfoCountField::decode(value) + delta;
    // We can get negative count here when the type-feedback info is
    // shared between two code objects. The can only happen when
    // the debugger made a shallow copy of code object (see Heap::CopyCode).
    // Since we do not optimize when the debugger is active, we can skip
    // this counter update.
    if (new_count >= 0) {
      new_count &= ICsWithTypeInfoCountField::kMask;
      value = ICsWithTypeInfoCountField::update(value, new_count);
      WRITE_FIELD(this, kStorage2Offset, Smi::FromInt(value));
    }
  }
  
  
  int TypeFeedbackInfo::ic_generic_count() {
    return Smi::cast(READ_FIELD(this, kStorage3Offset))->value();
  }
  
  
  void TypeFeedbackInfo::change_ic_generic_count(int delta) {
    if (delta == 0) return;
    int new_count = ic_generic_count() + delta;
    if (new_count >= 0) {
      new_count &= ~Smi::kMinValue;
      WRITE_FIELD(this, kStorage3Offset, Smi::FromInt(new_count));
    }
  }
  
  
  void TypeFeedbackInfo::initialize_storage() {
    WRITE_FIELD(this, kStorage1Offset, Smi::FromInt(0));
    WRITE_FIELD(this, kStorage2Offset, Smi::FromInt(0));
    WRITE_FIELD(this, kStorage3Offset, Smi::FromInt(0));
  }
  
  
  void TypeFeedbackInfo::change_own_type_change_checksum() {
    int value = Smi::cast(READ_FIELD(this, kStorage1Offset))->value();
    int checksum = OwnTypeChangeChecksum::decode(value);
    checksum = (checksum + 1) % (1 << kTypeChangeChecksumBits);
    value = OwnTypeChangeChecksum::update(value, checksum);
    // Ensure packed bit field is in Smi range.
    if (value > Smi::kMaxValue) value |= Smi::kMinValue;
    if (value < Smi::kMinValue) value &= ~Smi::kMinValue;
    WRITE_FIELD(this, kStorage1Offset, Smi::FromInt(value));
  }
  
  
  void TypeFeedbackInfo::set_inlined_type_change_checksum(int checksum) {
    int value = Smi::cast(READ_FIELD(this, kStorage2Offset))->value();
    int mask = (1 << kTypeChangeChecksumBits) - 1;
    value = InlinedTypeChangeChecksum::update(value, checksum & mask);
    // Ensure packed bit field is in Smi range.
    if (value > Smi::kMaxValue) value |= Smi::kMinValue;
    if (value < Smi::kMinValue) value &= ~Smi::kMinValue;
    WRITE_FIELD(this, kStorage2Offset, Smi::FromInt(value));
  }
  
  
  int TypeFeedbackInfo::own_type_change_checksum() {
    int value = Smi::cast(READ_FIELD(this, kStorage1Offset))->value();
    return OwnTypeChangeChecksum::decode(value);
  }
  
  
  bool TypeFeedbackInfo::matches_inlined_type_change_checksum(int checksum) {
    int value = Smi::cast(READ_FIELD(this, kStorage2Offset))->value();
    int mask = (1 << kTypeChangeChecksumBits) - 1;
    return InlinedTypeChangeChecksum::decode(value) == (checksum & mask);
  }
  
  
  SMI_ACCESSORS(AliasedArgumentsEntry, aliased_context_slot, kAliasedContextSlot)
  
  
  Relocatable::Relocatable(Isolate* isolate) {
    isolate_ = isolate;
    prev_ = isolate->relocatable_top();
    isolate->set_relocatable_top(this);
  }
  
  
  Relocatable::~Relocatable() {
    DCHECK_EQ(isolate_->relocatable_top(), this);
    isolate_->set_relocatable_top(prev_);
  }
  
  
  template<class Derived, class TableType>
  Object* OrderedHashTableIterator<Derived, TableType>::CurrentKey() {
    TableType* table(TableType::cast(this->table()));
    int index = Smi::cast(this->index())->value();
    Object* key = table->KeyAt(index);
    DCHECK(!key->IsTheHole());
    return key;
  }
  
  
  void JSSetIterator::PopulateValueArray(FixedArray* array) {
    array->set(0, CurrentKey());
  }
  
  
  void JSMapIterator::PopulateValueArray(FixedArray* array) {
    array->set(0, CurrentKey());
    array->set(1, CurrentValue());
  }
  
  
  Object* JSMapIterator::CurrentValue() {
    OrderedHashMap* table(OrderedHashMap::cast(this->table()));
    int index = Smi::cast(this->index())->value();
    Object* value = table->ValueAt(index);
    DCHECK(!value->IsTheHole());
    return value;
  }
  
  
  String::SubStringRange::SubStringRange(String* string, int first, int length)
      : string_(string),
        first_(first),
        length_(length == -1 ? string->length() : length) {}
  
  
  class String::SubStringRange::iterator final {
   public:
    typedef std::forward_iterator_tag iterator_category;
    typedef int difference_type;
    typedef uc16 value_type;
    typedef uc16* pointer;
    typedef uc16& reference;
  
    iterator(const iterator& other)
        : content_(other.content_), offset_(other.offset_) {}
  
    uc16 operator*() { return content_.Get(offset_); }
    bool operator==(const iterator& other) const {
      return content_.UsesSameString(other.content_) && offset_ == other.offset_;
    }
    bool operator!=(const iterator& other) const {
      return !content_.UsesSameString(other.content_) || offset_ != other.offset_;
    }
    iterator& operator++() {
      ++offset_;
      return *this;
    }
    iterator operator++(int);
  
   private:
    friend class String;
    iterator(String* from, int offset)
        : content_(from->GetFlatContent()), offset_(offset) {}
    String::FlatContent content_;
    int offset_;
  };
  
  
  String::SubStringRange::iterator String::SubStringRange::begin() {
    return String::SubStringRange::iterator(string_, first_);
  }
  
  
  String::SubStringRange::iterator String::SubStringRange::end() {
    return String::SubStringRange::iterator(string_, first_ + length_);
  }
  
  
  // Predictably converts HeapObject* or Address to uint32 by calculating
  // offset of the address in respective MemoryChunk.
  static inline uint32_t ObjectAddressForHashing(void* object) {
    uint32_t value = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(object));
    return value & MemoryChunk::kAlignmentMask;
  }
  
  static inline Handle<Object> MakeEntryPair(Isolate* isolate, uint32_t index,
                                             Handle<Object> value) {
    Handle<Object> key = isolate->factory()->Uint32ToString(index);
    Handle<FixedArray> entry_storage =
        isolate->factory()->NewUninitializedFixedArray(2);
    {
      entry_storage->set(0, *key, SKIP_WRITE_BARRIER);
      entry_storage->set(1, *value, SKIP_WRITE_BARRIER);
    }
    return isolate->factory()->NewJSArrayWithElements(entry_storage,
                                                      FAST_ELEMENTS, 2);
  }
  
  static inline Handle<Object> MakeEntryPair(Isolate* isolate, Handle<Name> key,
                                             Handle<Object> value) {
    Handle<FixedArray> entry_storage =
        isolate->factory()->NewUninitializedFixedArray(2);
    {
      entry_storage->set(0, *key, SKIP_WRITE_BARRIER);
      entry_storage->set(1, *value, SKIP_WRITE_BARRIER);
    }
    return isolate->factory()->NewJSArrayWithElements(entry_storage,
                                                      FAST_ELEMENTS, 2);
  }
  
  #undef TYPE_CHECKER
  #undef CAST_ACCESSOR
  #undef INT_ACCESSORS
  #undef ACCESSORS
  #undef SMI_ACCESSORS
  #undef SYNCHRONIZED_SMI_ACCESSORS
  #undef NOBARRIER_SMI_ACCESSORS
  #undef BOOL_GETTER
  #undef BOOL_ACCESSORS
  #undef FIELD_ADDR
  #undef FIELD_ADDR_CONST
  #undef READ_FIELD
  #undef NOBARRIER_READ_FIELD
  #undef WRITE_FIELD
  #undef NOBARRIER_WRITE_FIELD
  #undef WRITE_BARRIER
  #undef CONDITIONAL_WRITE_BARRIER
  #undef READ_DOUBLE_FIELD
  #undef WRITE_DOUBLE_FIELD
  #undef READ_INT_FIELD
  #undef WRITE_INT_FIELD
  #undef READ_INTPTR_FIELD
  #undef WRITE_INTPTR_FIELD
  #undef READ_UINT8_FIELD
  #undef WRITE_UINT8_FIELD
  #undef READ_INT8_FIELD
  #undef WRITE_INT8_FIELD
  #undef READ_UINT16_FIELD
  #undef WRITE_UINT16_FIELD
  #undef READ_INT16_FIELD
  #undef WRITE_INT16_FIELD
  #undef READ_UINT32_FIELD
  #undef WRITE_UINT32_FIELD
  #undef READ_INT32_FIELD
  #undef WRITE_INT32_FIELD
  #undef READ_FLOAT_FIELD
  #undef WRITE_FLOAT_FIELD
  #undef READ_UINT64_FIELD
  #undef WRITE_UINT64_FIELD
  #undef READ_INT64_FIELD
  #undef WRITE_INT64_FIELD
  #undef READ_BYTE_FIELD
  #undef WRITE_BYTE_FIELD
  #undef NOBARRIER_READ_BYTE_FIELD
  #undef NOBARRIER_WRITE_BYTE_FIELD
  
  }  // namespace internal
  }  // namespace v8
  
  #endif  // V8_OBJECTS_INL_H_
  