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// 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.
#include "src/objects/fixed-array.h"
#include "src/objects/objects.h"
#include "src/objects/struct.h"
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
namespace v8 {
namespace internal {
// Container for metadata stored on each prototype map.
class PrototypeInfo : public Struct {
static const int UNREGISTERED = -1;
// [module_namespace]: A backpointer to JSModuleNamespace from its
// PrototypeInfo (or undefined). This field is only used for JSModuleNamespace
// maps. TODO(jkummerow): Figure out if there's a way to store the namespace
// pointer elsewhere to save memory.
DECL_ACCESSORS(module_namespace, Object)
// [prototype_users]: WeakArrayList containing weak references to maps using
// this prototype, or Smi(0) if uninitialized.
DECL_ACCESSORS(prototype_users, Object)
// [object_create_map]: A field caching the map for Object.create(prototype).
static inline void SetObjectCreateMap(Handle<PrototypeInfo> info,
Handle<Map> map);
inline Map ObjectCreateMap();
inline bool HasObjectCreateMap();
// [registry_slot]: Slot in prototype's user registry where this user
// is stored. Returns UNREGISTERED if this prototype has not been registered.
inline int registry_slot() const;
inline void set_registry_slot(int slot);
// [bit_field]
inline int bit_field() const;
inline void set_bit_field(int bit_field);
// Dispatched behavior.
// Bit field usage.
static const int kShouldBeFastBit = 0;
class BodyDescriptor;
DECL_ACCESSORS(object_create_map, MaybeObject)
OBJECT_CONSTRUCTORS(PrototypeInfo, Struct);
// A growing array with an additional API for marking slots "empty". When adding
// new elements, we reuse the empty slots instead of growing the array.
class V8_EXPORT_PRIVATE PrototypeUsers : public WeakArrayList {
static Handle<WeakArrayList> Add(Isolate* isolate,
Handle<WeakArrayList> array,
Handle<Map> value, int* assigned_index);
static inline void MarkSlotEmpty(WeakArrayList array, int index);
// The callback is called when a weak pointer to HeapObject "object" is moved
// from index "from_index" to index "to_index" during compaction. The callback
// must not cause GC.
using CompactionCallback = void (*)(HeapObject object, int from_index,
int to_index);
static WeakArrayList Compact(
Handle<WeakArrayList> array, Heap* heap, CompactionCallback callback,
AllocationType allocation = AllocationType::kYoung);
static void Verify(WeakArrayList array);
#endif // VERIFY_HEAP
static const int kEmptySlotIndex = 0;
static const int kFirstIndex = 1;
static const int kNoEmptySlotsMarker = 0;
static inline Smi empty_slot_index(WeakArrayList array);
static inline void set_empty_slot_index(WeakArrayList array, int index);
static void IsSlotEmpty(WeakArrayList array, int index);
} // namespace internal
} // namespace v8
#include "src/objects/object-macros-undef.h"