If a large object is truncated, also truncate the page.

runtime/vm/gc_sweeper.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_GC_SWEEPER_H_
 #define VM_GC_SWEEPER_H_
 
 #include "vm/globals.h"
 
 namespace dart {
 
 // Forward declarations.
 class FreeList;
 class Heap;
 class HeapPage;
 
 // The class GCSweeper is used to visit the heap after marking to reclaim unused
 // memory.
 class GCSweeper {
  public:
   explicit GCSweeper(Heap* heap) : heap_(heap) {}
   ~GCSweeper() {}
 
   // Sweep the memory area for the page while clearing the mark bits and adding
   // all the unmarked objects to the freelist.
   // Returns true if the page is in use.
   bool SweepPage(HeapPage* page, FreeList* freelist);
 
-  bool SweepLargePage(HeapPage* page);
+  // Returns the number of bytes from page->object_start() to the end of the

[Ivan Posva, 2014/06/30 05:51:05]

Please change this to "number of words" and update the corresponding code.

[koda, 2014/06/30 22:57:48]

Done.

+  // last marked object.
+  intptr_t SweepLargePage(HeapPage* page);
 
  private:
   Heap* heap_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(GCSweeper);
 };
 
 }  // namespace dart
 
 #endif  // VM_GC_SWEEPER_H_