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// Copyright 2020 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_MARKING_BARRIER_INL_H_
#define V8_HEAP_MARKING_BARRIER_INL_H_
#include "src/heap/incremental-marking-inl.h"
#include "src/heap/incremental-marking.h"
#include "src/heap/marking-barrier.h"
namespace v8 {
namespace internal {
bool MarkingBarrier::MarkValue(HeapObject host, HeapObject value) {
DCHECK(IsCurrentMarkingBarrier());
DCHECK(is_activated_);
DCHECK(!marking_state_.IsImpossible(value));
// Host may have an impossible markbit pattern if manual allocation folding
// is performed and host happens to be the last word of an allocated region.
// In that case host has only one markbit and the second markbit belongs to
// another object. We can detect that case by checking if value is a one word
// filler map.
DCHECK(!marking_state_.IsImpossible(host) ||
value == ReadOnlyRoots(heap_->isolate()).one_pointer_filler_map());
if (!V8_CONCURRENT_MARKING_BOOL && !marking_state_.IsBlack(host)) {
// The value will be marked and the slot will be recorded when the marker
// visits the host object.
return false;
}
if (WhiteToGreyAndPush(value)) {
if (is_main_thread_barrier_) {
incremental_marking_->RestartIfNotMarking();
}
if (V8_UNLIKELY(FLAG_track_retaining_path)) {
heap_->AddRetainingRoot(Root::kWriteBarrier, value);
}
}
return true;
}
template <typename TSlot>
inline void MarkingBarrier::MarkRange(HeapObject host, TSlot start, TSlot end) {
auto* isolate = heap_->isolate();
for (TSlot slot = start; slot < end; ++slot) {
typename TSlot::TObject object = slot.Relaxed_Load();
HeapObject heap_object;
// Mark both, weak and strong edges.
if (object.GetHeapObject(isolate, &heap_object)) {
if (MarkValue(host, heap_object) && is_compacting_) {
collector_->RecordSlot(host, HeapObjectSlot(slot), heap_object);
}
}
}
}
bool MarkingBarrier::WhiteToGreyAndPush(HeapObject obj) {
if (marking_state_.WhiteToGrey(obj)) {
worklist_.Push(obj);
return true;
}
return false;
}
} // namespace internal
} // namespace v8
#endif // V8_HEAP_MARKING_BARRIER_INL_H_
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