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[heap] Remove live weak cells from weak cell list when finalizing incremental marking.

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BUG=chromium:548562
LOG=n

Review URL: https://codereview.chromium.org/1474303002

Cr-Commit-Position: refs/heads/master@{#32372}
This commit is contained in:
hpayer 2015-11-27 04:32:30 -08:00 committed by Commit bot
parent 508f122dec
commit 6190c608c8
2 changed files with 42 additions and 0 deletions
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41
src/heap/incremental-marking.cc
View File

@ -647,6 +647,44 @@ void IncrementalMarking::MarkObjectGroups() {
}
void IncrementalMarking::ProcessWeakCells() {
DCHECK(FLAG_finalize_marking_incrementally);
DCHECK(!finalize_marking_completed_);
DCHECK(IsMarking());
Object* weak_cell_obj = heap()->encountered_weak_cells();
Object* weak_cell_head = Smi::FromInt(0);
WeakCell* prev_weak_cell_obj = NULL;
while (weak_cell_obj != Smi::FromInt(0)) {
WeakCell* weak_cell = reinterpret_cast<WeakCell*>(weak_cell_obj);
// We do not insert cleared weak cells into the list, so the value
// cannot be a Smi here.
HeapObject* value = HeapObject::cast(weak_cell->value());
// Remove weak cells with live objects from the list, they do not need
// clearing.
if (MarkCompactCollector::IsMarked(value)) {
// Record slot, if value is pointing to an evacuation candidate.
Object** slot = HeapObject::RawField(weak_cell, WeakCell::kValueOffset);
heap_->mark_compact_collector()->RecordSlot(weak_cell, slot, *slot);
// Remove entry somewhere after top.
if (prev_weak_cell_obj != NULL) {
prev_weak_cell_obj->set_next(weak_cell->next());
}
weak_cell_obj = weak_cell->next();
weak_cell->clear_next(heap());
} else {
if (weak_cell_head == Smi::FromInt(0)) {
weak_cell_head = weak_cell;
}
prev_weak_cell_obj = weak_cell;
weak_cell_obj = weak_cell->next();
}
}
// Top may have changed.
heap()->set_encountered_weak_cells(weak_cell_head);
}
void IncrementalMarking::FinalizeIncrementally() {
DCHECK(FLAG_finalize_marking_incrementally);
DCHECK(!finalize_marking_completed_);
@ -659,8 +697,11 @@ void IncrementalMarking::FinalizeIncrementally() {
// objects to reduce the marking load in the final pause.
// 1) We scan and mark the roots again to find all changes to the root set.
// 2) We mark the object groups.
// 3) Remove weak cell with live values from the list of weak cells, they
// do not need processing during GC.
MarkRoots();
MarkObjectGroups();
ProcessWeakCells();
int marking_progress =
abs(old_marking_deque_top -

1
src/heap/incremental-marking.h
View File

@ -240,6 +240,7 @@ class IncrementalMarking {
void MarkRoots();
void MarkObjectGroups();
void ProcessWeakCells();
void ActivateIncrementalWriteBarrier(PagedSpace* space);
static void ActivateIncrementalWriteBarrier(NewSpace* space);