src/objects/property-array.h

// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_OBJECTS_PROPERTY_ARRAY_H_
#define V8_OBJECTS_PROPERTY_ARRAY_H_

#include "src/objects/heap-object.h"

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

namespace v8 {
namespace internal {

class PropertyArray : public HeapObject {
 public:
  // [length]: length of the array.
  inline int length() const;

  // Get the length using acquire loads.
  inline int synchronized_length() const;

  // This is only used on a newly allocated PropertyArray which
  // doesn't have an existing hash.
  inline void initialize_length(int length);

  inline void SetHash(int hash);
  inline int Hash() const;

  inline Object* get(int index) const;

  inline void set(int index, Object* value);
  // Setter with explicit barrier mode.
  inline void set(int index, Object* value, WriteBarrierMode mode);

  // Gives access to raw memory which stores the array's data.
  inline ObjectSlot data_start();

  // Garbage collection support.
  static constexpr int SizeFor(int length) {
    return kHeaderSize + length * kTaggedSize;
  }
  static constexpr int OffsetOfElementAt(int index) { return SizeFor(index); }

  DECL_CAST2(PropertyArray)
  DECL_PRINTER(PropertyArray)
  DECL_VERIFIER(PropertyArray)

// Layout description.
#define PROPERTY_ARRAY_FIELDS(V)       \
  V(kLengthAndHashOffset, kTaggedSize) \
  /* Header size. */                   \
  V(kHeaderSize, 0)

  DEFINE_FIELD_OFFSET_CONSTANTS(HeapObject::kHeaderSize, PROPERTY_ARRAY_FIELDS)
#undef PROPERTY_ARRAY_FIELDS

  // Garbage collection support.
  typedef FlexibleBodyDescriptor<kHeaderSize> BodyDescriptor;

  static const int kLengthFieldSize = 10;
  class LengthField : public BitField<int, 0, kLengthFieldSize> {};
  static const int kMaxLength = LengthField::kMax;
  class HashField : public BitField<int, kLengthFieldSize,
                                    kSmiValueSize - kLengthFieldSize - 1> {};

  static const int kNoHashSentinel = 0;

  OBJECT_CONSTRUCTORS(PropertyArray, HeapObject);
};

}  // namespace internal
}  // namespace v8

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

#endif  // V8_OBJECTS_PROPERTY_ARRAY_H_