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Just add slots that point to to-space objects back to the store buffer.

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BUG=

Review URL: https://codereview.chromium.org/946973008

Cr-Commit-Position: refs/heads/master@{#26844}
This commit is contained in:
hpayer 2015-02-25 02:29:37 -08:00 committed by Commit bot
parent 6a42682975
commit fd35be4065
2 changed files with 34 additions and 31 deletions
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62
src/heap/store-buffer.cc
View File

@ -378,27 +378,41 @@ void StoreBuffer::GCEpilogue() {
}
void StoreBuffer::ProcessOldToNewSlot(Address slot_address,
ObjectSlotCallback slot_callback,
bool clear_maps) {
Object** slot = reinterpret_cast<Object**>(slot_address);
Object* object = reinterpret_cast<Object*>(
base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(slot)));
// If the object is not in from space, it must be a duplicate store buffer
// entry and the slot was already updated.
if (heap_->InFromSpace(object)) {
HeapObject* heap_object = reinterpret_cast<HeapObject*>(object);
DCHECK(heap_object->IsHeapObject());
// The new space object was not promoted if it still contains a map
// pointer. Clear the map field now lazily (during full GC).
if (clear_maps) ClearDeadObject(heap_object);
slot_callback(reinterpret_cast<HeapObject**>(slot), heap_object);
object = reinterpret_cast<Object*>(
base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(slot)));
// If the object was in from space before and is after executing the
// callback in to space, the object is still live.
// Unfortunately, we do not know about the slot. It could be in a
// just freed free space object.
if (heap_->InToSpace(object)) {
EnterDirectlyIntoStoreBuffer(reinterpret_cast<Address>(slot));
}
}
}
void StoreBuffer::FindPointersToNewSpaceInRegion(
Address start, Address end, ObjectSlotCallback slot_callback,
bool clear_maps) {
for (Address slot_address = start; slot_address < end;
slot_address += kPointerSize) {
Object** slot = reinterpret_cast<Object**>(slot_address);
Object* object = reinterpret_cast<Object*>(
base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(slot)));
if (heap_->InNewSpace(object)) {
HeapObject* heap_object = reinterpret_cast<HeapObject*>(object);
DCHECK(heap_object->IsHeapObject());
// The new space object was not promoted if it still contains a map
// pointer. Clear the map field now lazily.
if (clear_maps) ClearDeadObject(heap_object);
slot_callback(reinterpret_cast<HeapObject**>(slot), heap_object);
object = reinterpret_cast<Object*>(
base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(slot)));
if (heap_->InNewSpace(object)) {
EnterDirectlyIntoStoreBuffer(slot_address);
}
}
ProcessOldToNewSlot(slot_address, slot_callback, clear_maps);
}
}
@ -413,21 +427,7 @@ void StoreBuffer::IteratePointersInStoreBuffer(ObjectSlotCallback slot_callback,
#ifdef DEBUG
Address* saved_top = old_top_;
#endif
Object** slot = reinterpret_cast<Object**>(*current);
Object* object = reinterpret_cast<Object*>(
base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(slot)));
if (heap_->InFromSpace(object)) {
HeapObject* heap_object = reinterpret_cast<HeapObject*>(object);
// The new space object was not promoted if it still contains a map
// pointer. Clear the map field now lazily.
if (clear_maps) ClearDeadObject(heap_object);
slot_callback(reinterpret_cast<HeapObject**>(slot), heap_object);
object = reinterpret_cast<Object*>(
base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(slot)));
if (heap_->InNewSpace(object)) {
EnterDirectlyIntoStoreBuffer(reinterpret_cast<Address>(slot));
}
}
ProcessOldToNewSlot(*current, slot_callback, clear_maps);
DCHECK(old_top_ == saved_top + 1 || old_top_ == saved_top);
}
}

3
src/heap/store-buffer.h
View File

@ -148,6 +148,9 @@ class StoreBuffer {
// Set the map field of the object to NULL if contains a map.
inline void ClearDeadObject(HeapObject* object);
void ProcessOldToNewSlot(Address slot_address,
ObjectSlotCallback slot_callback, bool clear_maps);
void IteratePointersToNewSpace(ObjectSlotCallback callback, bool clear_maps);
void FindPointersToNewSpaceInRegion(Address start, Address end,