New page local store buffer.

src/heap/mark-compact.cc

Index: src/heap/mark-compact.cc
diff --git a/src/heap/mark-compact.cc b/src/heap/mark-compact.cc
index 8338c5c38b9cb4650249d84c62e62ee6eeea9884..393ba6d3724a4009c7fbdb51f7f413aac481145c 100644
--- a/src/heap/mark-compact.cc
+++ b/src/heap/mark-compact.cc
@@ -2881,11 +2881,12 @@ void MarkCompactCollector::UpdateSlotsRecordedIn(SlotsBuffer* buffer) {
 
 static void UpdatePointer(HeapObject** address, HeapObject* object) {
   MapWord map_word = object->map_word();
-  // The store buffer can still contain stale pointers in dead large objects.
+  // The store buffer can still contain stale pointers in large object
+  // or in map spaces.

[Hannes Payer (out of office), 2016/01/20 19:43:00]

Why map space?

[ulan, 2016/01/28 19:07:22]

Clarified the comment.
Since we only filter invalid slots in old space, the store buffer can
still contain stale pointers in large object and in map spaces. Ignore
these pointers here.

   // Ignore these pointers here.
   DCHECK(map_word.IsForwardingAddress() ||
-         object->GetHeap()->lo_space()->FindPage(
-             reinterpret_cast<Address>(address)) != NULL);
+         !object->GetHeap()->old_space()->Contains(
+             reinterpret_cast<Address>(address)));
   if (map_word.IsForwardingAddress()) {
     // Update the corresponding slot.
     *address = map_word.ToForwardingAddress();
@@ -3218,7 +3219,6 @@ void MarkCompactCollector::EvacuatePagesInParallel() {
         //   entries of such pages are filtered before rescanning.
         DCHECK(p->IsEvacuationCandidate());
         p->SetFlag(Page::COMPACTION_WAS_ABORTED);
-        p->set_scan_on_scavenge(true);
         abandoned_pages++;
         break;
       case MemoryChunk::kCompactingFinalize:
@@ -3508,6 +3508,10 @@ bool MarkCompactCollector::VisitLiveObjects(MemoryChunk* page,
         page->markbits()->ClearRange(
             page->AddressToMarkbitIndex(page->area_start()),
             page->AddressToMarkbitIndex(object->address()));
+        if (page->old_to_new_slots() != nullptr) {
+          page->old_to_new_slots()->RemoveRange(
+              0, static_cast<int>(object->address() - page->address()));
+        }
         RecomputeLiveBytes(page);
       }
       return false;
@@ -3673,8 +3677,6 @@ void MarkCompactCollector::UpdatePointersAfterEvacuation() {
     // Update roots.
     heap_->IterateRoots(&updating_visitor, VISIT_ALL_IN_SWEEP_NEWSPACE);
 
-    StoreBufferRebuildScope scope(heap_, heap_->store_buffer(),
-                                  &Heap::ScavengeStoreBufferCallback);
     heap_->store_buffer()->IteratePointersToNewSpace(&UpdatePointer);
   }
 
@@ -3776,7 +3778,6 @@ void MarkCompactCollector::ReleaseEvacuationCandidates() {
     if (!p->IsEvacuationCandidate()) continue;
     PagedSpace* space = static_cast<PagedSpace*>(p->owner());
     space->Free(p->area_start(), p->area_size());
-    p->set_scan_on_scavenge(false);
     p->ResetLiveBytes();
     CHECK(p->WasSwept());
     space->ReleasePage(p);