Do not left-trim arrays when concurrent sweeping is active.

src/mark-compact.h

 // Copyright 2012 the V8 project authors. All rights reserved.
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 // modification, are permitted provided that the following conditions are
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 //
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@@ skipping 720 matching lines @@
   bool IsConcurrentSweepingInProgress();
 
   void set_sequential_sweeping(bool sequential_sweeping) {
     sequential_sweeping_ = sequential_sweeping;
   }
 
   bool sequential_sweeping() const {
     return sequential_sweeping_;
   }
 
+  bool CanMoveObjectStart(HeapObject* object);

[Michael Starzinger, 2014/03/24 12:21:35]

nit: Shouldn't this actually be a predicate on the Heap class instead of the
MarkCompactCollector class?

[Hannes Payer (out of office), 2014/03/25 11:41:08]

Done.

+
   // Mark the global table which maps weak objects to dependent code without
   // marking its contents.
   void MarkWeakObjectToCodeTable();
 
   // Special case for processing weak references in a full collection. We need
   // to artifically keep AllocationSites alive for a time.
   void MarkAllocationSite(AllocationSite* site);
 
  private:
   class SweeperTask;
@@ skipping 284 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 
 } }  // namespace v8::internal
 
 #endif  // V8_MARK_COMPACT_H_