src/heap/heap-write-barrier.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_HEAP_HEAP_WRITE_BARRIER_H_
#define V8_HEAP_HEAP_WRITE_BARRIER_H_

#include "include/v8-internal.h"
#include "src/base/optional.h"
#include "src/common/globals.h"
#include "src/objects/heap-object.h"

namespace v8 {
namespace internal {

class ArrayBufferExtension;
class InstructionStream;
class DescriptorArray;
class EphemeronHashTable;
class FixedArray;
class Heap;
class JSArrayBuffer;
class Map;
class MarkCompactCollector;
class MarkingBarrier;
class RelocInfo;

// Note: In general it is preferred to use the macros defined in
// object-macros.h.

// Combined write barriers.
void WriteBarrierForCode(InstructionStream host, RelocInfo* rinfo, Object value,
                         WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
void WriteBarrierForCode(InstructionStream host, RelocInfo* rinfo,
                         HeapObject value,
                         WriteBarrierMode mode = UPDATE_WRITE_BARRIER);

void CombinedWriteBarrier(HeapObject object, ObjectSlot slot, Object value,
                          WriteBarrierMode mode);
void CombinedWriteBarrier(HeapObject object, MaybeObjectSlot slot,
                          MaybeObject value, WriteBarrierMode mode);

void CombinedEphemeronWriteBarrier(EphemeronHashTable object, ObjectSlot slot,
                                   Object value, WriteBarrierMode mode);

// Generational write barrier.
void GenerationalBarrierForCode(InstructionStream host, RelocInfo* rinfo,
                                HeapObject object);

inline bool IsReadOnlyHeapObject(HeapObject object);

class V8_EXPORT_PRIVATE WriteBarrier {
 public:
  static inline void Marking(HeapObject host, ObjectSlot, Object value);
  static inline void Marking(HeapObject host, HeapObjectSlot, HeapObject value);
  static inline void Marking(HeapObject host, MaybeObjectSlot,
                             MaybeObject value);
  static inline void Marking(InstructionStream host, RelocInfo*,
                             HeapObject value);
  static inline void Marking(JSArrayBuffer host, ArrayBufferExtension*);
  static inline void Marking(DescriptorArray, int number_of_own_descriptors);

  static inline void Shared(InstructionStream host, RelocInfo*,
                            HeapObject value);

  // It is invoked from generated code and has to take raw addresses.
  static int MarkingFromCode(Address raw_host, Address raw_slot);
  static int SharedMarkingFromCode(Address raw_host, Address raw_slot);
  static int SharedFromCode(Address raw_host, Address raw_slot);

  // Invoked from global handles where no host object is available.
  static inline void MarkingFromGlobalHandle(Object value);

  static inline void CombinedBarrierFromInternalFields(JSObject host,
                                                       void* value);
  static inline void CombinedBarrierFromInternalFields(JSObject host,
                                                       size_t argc,
                                                       void** values);

  static MarkingBarrier* SetForThread(MarkingBarrier*);

  static MarkingBarrier* CurrentMarkingBarrier(
      HeapObject verification_candidate);

#ifdef ENABLE_SLOW_DCHECKS
  template <typename T>
  static inline bool IsRequired(HeapObject host, T value);
  static bool IsImmortalImmovableHeapObject(HeapObject object);
#endif

  static void MarkingSlow(HeapObject host, HeapObjectSlot, HeapObject value);

 private:
  static inline bool IsMarking(HeapObject object);

  static void MarkingSlow(InstructionStream host, RelocInfo*, HeapObject value);
  static void MarkingSlow(JSArrayBuffer host, ArrayBufferExtension*);
  static void MarkingSlow(DescriptorArray, int number_of_own_descriptors);
  static void MarkingSlowFromGlobalHandle(HeapObject value);
  static void MarkingSlowFromInternalFields(Heap* heap, JSObject host);

  static inline void GenerationalBarrierFromInternalFields(JSObject host,
                                                           void* value);
  static inline void GenerationalBarrierFromInternalFields(JSObject host,
                                                           size_t argc,
                                                           void** values);

  static void SharedSlow(InstructionStream host, RelocInfo*, HeapObject value);

  friend class Heap;
};

}  // namespace internal
}  // namespace v8

#endif  // V8_HEAP_HEAP_WRITE_BARRIER_H_