- Implement the old sweeper.

vm/pages.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_PAGES_H_
 #define VM_PAGES_H_
 
+#include "vm/freelist.h"
 #include "vm/globals.h"
 #include "vm/virtual_memory.h"
 
 namespace dart {
 
 // Forward declarations.
 class Heap;
 class ObjectPointerVisitor;
 
 // An aligned page containing old generation objects. Alignment is used to be
@@ skipping 63 matching lines @@
   }
   static intptr_t IsPageAllocatableSize(intptr_t size) {
     return size <= kAllocatablePageSize;
   }
 
   void VisitObjectPointers(ObjectPointerVisitor* visitor) const;
 
   // Collect the garbage in the page space using mark-sweep.
   void MarkSweep();
 
+  static HeapPage* PageFor(RawObject* raw_obj) {
+    return reinterpret_cast<HeapPage*>(
+        RawObject::ToAddr(raw_obj) & ~(kPageSize -1));
+  }
+
  private:
   static const intptr_t kAllocatablePageSize = kPageSize - sizeof(HeapPage);
 
   void AllocatePage();
   HeapPage* AllocateLargePage(intptr_t size);
+  void FreeLargePage(HeapPage* page, HeapPage* previous_page);
   void FreePages(HeapPage* pages);
 
   uword TryBumpAllocate(intptr_t size);
 
+  FreeList freelist_;
+
   Heap* heap_;
 
   HeapPage* pages_;
   HeapPage* pages_tail_;
   HeapPage* large_pages_;
 
   // Various sizes being tracked for this generation.
   intptr_t max_capacity_;
   intptr_t capacity_;
   intptr_t in_use_;
 
   // Old-gen GC cycle count.
   int count_;
 
   bool is_executable_;
 
   // Keep track whether a MarkSweep is currently running.
   bool sweeping_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PageSpace);
 };
 
 }  // namespace dart
 
 #endif  // VM_PAGES_H_