[heap] Various new LO spaces fixes in Scavenger.

Bug: chromium:852420
Change-Id: I54db2251378147df63ca20f3d32d286186f3b784
Reviewed-on: https://chromium-review.googlesource.com/c/1352306Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57903}

src/heap/scavenger-inl.h

@@ -219,8 +219,11 @@ SlotCallbackResult Scavenger::RememberedSetEntryNeeded(
 
 bool Scavenger::HandleLargeObject(Map map, HeapObject* object,
                                   int object_size) {
-  if (V8_UNLIKELY(FLAG_young_generation_large_objects &&
-                  object_size > kMaxRegularHeapObjectSize)) {
+  // TODO(hpayer): Make this check size based, i.e.
+  // object_size > kMaxRegularHeapObjectSize
+  if (V8_UNLIKELY(
+          FLAG_young_generation_large_objects &&
+          MemoryChunk::FromHeapObject(object)->IsInNewLargeObjectSpace())) {
     DCHECK_EQ(NEW_LO_SPACE,
               MemoryChunk::FromHeapObject(object)->owner()->identity());
     if (object->map_slot().Release_CompareAndSwap(

src/heap/spaces.cc

@@ -3558,6 +3558,8 @@ void LargeObjectSpace::FreeUnmarkedObjects() {
   LargePage* current = first_page();
   IncrementalMarking::NonAtomicMarkingState* marking_state =
       heap()->incremental_marking()->non_atomic_marking_state();
+  // Right-trimming does not update the objects_size_ counter. We are lazily
+  // updating it after every GC.
   objects_size_ = 0;
   while (current) {
     LargePage* next_current = current->next_page();
@@ -3759,7 +3761,9 @@ void NewLargeObjectSpace::FreeAllObjects() {
         current);
     current = next_current;
   }
-  DCHECK_EQ(objects_size_, 0);
+  // Right-trimming does not update the objects_size_ counter. We are lazily
+  // updating it after every GC.
+  objects_size_ = 0;
 }
 
 CodeLargeObjectSpace::CodeLargeObjectSpace(Heap* heap)