src/heap/remembered-set.cc

// Copyright 2016 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/heap/remembered-set.h"
#include "src/heap/heap-inl.h"
#include "src/heap/heap.h"
#include "src/heap/mark-compact.h"
#include "src/heap/slot-set.h"
#include "src/heap/spaces.h"
#include "src/heap/store-buffer.h"

namespace v8 {
namespace internal {

template <PointerDirection direction>
void RememberedSet<direction>::ClearInvalidSlots(Heap* heap) {
  STATIC_ASSERT(direction == OLD_TO_NEW);
  PageIterator it(heap->old_space());
  MemoryChunk* chunk;
  while (it.has_next()) {
    chunk = it.next();
    SlotSet* slots = GetSlotSet(chunk);
    if (slots != nullptr) {
      slots->Iterate([heap](Address addr) {
        Object** slot = reinterpret_cast<Object**>(addr);
        return IsValidSlot(heap, slot) ? SlotSet::KEEP_SLOT
                                       : SlotSet::REMOVE_SLOT;
      });
    }
  }
}

template <PointerDirection direction>
void RememberedSet<direction>::VerifyValidSlots(Heap* heap) {
  STATIC_ASSERT(direction == OLD_TO_NEW);
  Iterate(heap, [heap](Address addr) {
    Object** slot = reinterpret_cast<Object**>(addr);
    Object* object = *slot;
    if (Page::FromAddress(addr)->owner() != nullptr &&
        Page::FromAddress(addr)->owner()->identity() == OLD_SPACE) {
      CHECK(IsValidSlot(heap, slot));
      heap->mark_compact_collector()->VerifyIsSlotInLiveObject(
          reinterpret_cast<Address>(slot), HeapObject::cast(object));
    }
    return SlotSet::KEEP_SLOT;
  });
}

template <PointerDirection direction>
bool RememberedSet<direction>::IsValidSlot(Heap* heap, Object** slot) {
  STATIC_ASSERT(direction == OLD_TO_NEW);
  Object* object = *slot;
  if (!heap->InNewSpace(object)) {
    return false;
  }
  HeapObject* heap_object = HeapObject::cast(object);
  // If the target object is not black, the source slot must be part
  // of a non-black (dead) object.
  return Marking::IsBlack(Marking::MarkBitFrom(heap_object)) &&
         heap->mark_compact_collector()->IsSlotInLiveObject(
             reinterpret_cast<Address>(slot));
}

template void RememberedSet<OLD_TO_NEW>::ClearInvalidSlots(Heap* heap);
template void RememberedSet<OLD_TO_NEW>::VerifyValidSlots(Heap* heap);

}  // namespace internal
}  // namespace v8