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

runtime/vm/gc_sweeper.cc

 // 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.
 
 #include "vm/gc_sweeper.h"
 
 #include "vm/freelist.h"
 #include "vm/globals.h"
 #include "vm/heap.h"
 #include "vm/pages.h"
@@ skipping 38 matching lines @@
       }
     }
     current += obj_size;
   }
   ASSERT(current == end);
 
   return in_use;
 }
 
 
-bool GCSweeper::SweepLargePage(HeapPage* page) {
-  bool in_use = false;
+intptr_t GCSweeper::SweepLargePage(HeapPage* page) {
+  intptr_t bytes_to_end = 0;
   RawObject* raw_obj = RawObject::FromAddr(page->object_start());
   if (raw_obj->IsMarked()) {
     raw_obj->ClearMarkBit();
-    in_use = true;
+    bytes_to_end += raw_obj->Size();

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

+= -> =

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

Done.

   }
 #ifdef DEBUG
   // String::MakeExternal and Array::MakeArray create trailing filler objects,
   // but they are always unreachable. Verify that they are not marked.
   uword current = RawObject::ToAddr(raw_obj) + raw_obj->Size();
   uword end = page->object_end();
   while (current < end) {
     RawObject* cur_obj = RawObject::FromAddr(current);
     ASSERT(!cur_obj->IsMarked());
     current += cur_obj->Size();
   }
 #endif  // DEBUG
-  return in_use;
+  return bytes_to_end;
 }
 
 }  // namespace dart