Access old space marking bits from runtime only when incremental marking is in MARKING state.

src/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 642 matching lines @@
 bool MarkCompactCollector::AreSweeperThreadsActivated() {
   return isolate()->sweeper_threads() != NULL || FLAG_job_based_sweeping;
 }
 
 
 bool MarkCompactCollector::IsConcurrentSweepingInProgress() {
   return sweeping_pending_;
 }
 
 
-bool Marking::TransferMark(Address old_start, Address new_start) {
+void Marking::TransferMark(Address old_start, Address new_start) {
   // This is only used when resizing an object.
   ASSERT(MemoryChunk::FromAddress(old_start) ==
          MemoryChunk::FromAddress(new_start));
 
+  if (!heap_->incremental_marking()->IsMarking()) return;
+
   // If the mark doesn't move, we don't check the color of the object.
   // It doesn't matter whether the object is black, since it hasn't changed
   // size, so the adjustment to the live data count will be zero anyway.
-  if (old_start == new_start) return false;
+  if (old_start == new_start) return;
 
   MarkBit new_mark_bit = MarkBitFrom(new_start);
   MarkBit old_mark_bit = MarkBitFrom(old_start);
 
 #ifdef DEBUG
   ObjectColor old_color = Color(old_mark_bit);
 #endif
 
   if (Marking::IsBlack(old_mark_bit)) {
     old_mark_bit.Clear();
     ASSERT(IsWhite(old_mark_bit));
     Marking::MarkBlack(new_mark_bit);
-    return true;
+    return;
   } else if (Marking::IsGrey(old_mark_bit)) {
-    ASSERT(heap_->incremental_marking()->IsMarking());
     old_mark_bit.Clear();
     old_mark_bit.Next().Clear();
     ASSERT(IsWhite(old_mark_bit));
     heap_->incremental_marking()->WhiteToGreyAndPush(
         HeapObject::FromAddress(new_start), new_mark_bit);
     heap_->incremental_marking()->RestartIfNotMarking();
   }
 
 #ifdef DEBUG
   ObjectColor new_color = Color(new_mark_bit);
   ASSERT(new_color == old_color);
 #endif
-
-  return false;
 }
 
 
 const char* AllocationSpaceName(AllocationSpace space) {
   switch (space) {
     case NEW_SPACE: return "NEW_SPACE";
     case OLD_POINTER_SPACE: return "OLD_POINTER_SPACE";
     case OLD_DATA_SPACE: return "OLD_DATA_SPACE";
     case CODE_SPACE: return "CODE_SPACE";
     case MAP_SPACE: return "MAP_SPACE";
@@ skipping 3802 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal