Request for comments on overall approach.

runtime/vm/scavenger.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/scavenger.h"
 
 #include "vm/dart.h"
 #include "vm/dart_api_state.h"
 #include "vm/isolate.h"
 #include "vm/object.h"
 #include "vm/stack_frame.h"
 #include "vm/verifier.h"
 #include "vm/visitor.h"
 
 namespace dart {
 
 enum {
-  kForwardingMask = 3,
-  kNotForwarded = 1,  // Tagged pointer.
-  kForwarded = 3,  // Tagged pointer and forwarding bit set.
+  kForwardingMask = 1,
+  kNotForwarded = 0,
+  kForwarded = 1,
 };
 
 
 static inline bool IsForwarding(uword header) {
   uword bits = header & kForwardingMask;
   ASSERT((bits == kNotForwarded) || (bits == kForwarded));
   return bits == kForwarded;
 }
 
 
@@ skipping 355 matching lines @@
     OS::PrintErr(" done.\n");
   }
 
   count_++;
   // Done scavenging. Reset the marker.
   ASSERT(scavenging_);
   scavenging_ = false;
 }
 
 }  // namespace dart