Added mark bit cell iterator.

src/mark-compact.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 934 matching lines @@
   CodeFlusher* code_flusher_;
   Object* encountered_weak_maps_;
 
   List<Page*> evacuation_candidates_;
   List<Code*> invalidated_code_;
 
   friend class Heap;
 };
 
 
+class MarkBitCellIterator BASE_EMBEDDED {
+ public:
+  explicit MarkBitCellIterator(MemoryChunk* chunk)
+      : chunk_(chunk) {
+    last_cell_index_ = Bitmap::IndexToCell(
+        Bitmap::CellAlignIndex(
+            chunk->AddressToMarkbitIndex(chunk->area_end())));
+    cell_base_ = chunk->area_start();
+    cell_index_ = Bitmap::IndexToCell(
+        Bitmap::CellAlignIndex(
+            chunk->AddressToMarkbitIndex(cell_base_)));
+    cells_ = chunk->markbits()->cells();
+  }
+
+  inline bool Done() { return cell_index_ == last_cell_index_; }
+
+  inline bool HasNext() { return cell_index_ < last_cell_index_ - 1; }
+
+  inline MarkBit::CellType* CurrentCell() {
+    ASSERT(cell_index_ == Bitmap::IndexToCell(Bitmap::CellAlignIndex(
+        chunk_->AddressToMarkbitIndex(cell_base_))));
+    return &cells_[cell_index_];
+  }
+
+  inline Address CurrentCellBase() {
+    ASSERT(cell_index_ == Bitmap::IndexToCell(Bitmap::CellAlignIndex(
+        chunk_->AddressToMarkbitIndex(cell_base_))));
+    return cell_base_;
+  }
+
+  inline void Advance() {
+    cell_index_++;
+    cell_base_ += 32 * kPointerSize;
+  }
+
+ private:
+  MemoryChunk* chunk_;
+  MarkBit::CellType* cells_;
+  unsigned int last_cell_index_;
+  unsigned int cell_index_;
+  Address cell_base_;
+};
+
+
 class SequentialSweepingScope BASE_EMBEDDED {
  public:
   explicit SequentialSweepingScope(MarkCompactCollector *collector) :
     collector_(collector) {
     collector_->set_sequential_sweeping(true);
   }
 
   ~SequentialSweepingScope() {
     collector_->set_sequential_sweeping(false);
   }
 
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 
 } }  // namespace v8::internal
 
 #endif  // V8_MARK_COMPACT_H_