- Implement the old sweeper.

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 the size of memory used by the marked objects.
+  intptr_t SweepPage(HeapPage* page, FreeList* freelist);
+
+  intptr_t SweepLargePage(HeapPage* page);
+
+ private:
+  Heap* heap_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(GCSweeper);
+};
+
+}  // namespace dart
+
+#endif  // VM_GC_SWEEPER_H_