Don't overload FreeListElement for become.

runtime/vm/compiler_stats.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/compiler_stats.h"
 
 #include "vm/flags.h"
 #include "vm/log.h"
 #include "vm/object_graph.h"
 #include "vm/object_store.h"
 #include "vm/timer.h"
 
 
 namespace dart {
 
 DEFINE_FLAG(bool, compiler_stats, false, "Compiler stat counters.");
 DEFINE_FLAG(bool, compiler_benchmark, false,
             "Compiler stat counters for benchmark.");
 
 
 class TokenStreamVisitor : public ObjectVisitor {
  public:
   explicit TokenStreamVisitor(CompilerStats* compiler_stats)
       : obj_(Object::Handle()),
         stats_(compiler_stats) {
   }
 
   void VisitObject(RawObject* raw_obj) {
-    if (raw_obj->IsFreeListElement()) {
+    if (raw_obj->IsFreeListElement() || raw_obj->IsForwardingCorpse()) {
       return;
     }
     obj_ = raw_obj;
     if (obj_.GetClassId() == TokenStream::kClassId) {
       TokenStream::Iterator tkit(Thread::Current()->zone(),
                                  TokenStream::Cast(obj_),
                                  TokenPosition::kMinSource,
                                  TokenStream::Iterator::kNoNewlines);
       Token::Kind kind = tkit.CurrentTokenKind();
       while (kind != Token::kEOS) {
@@ skipping 269 matching lines @@
   log.Print("  VarDesc size:          %" Pd64 " KB\n", vardesc_size / 1024);
   log.Flush();
   char* stats_text = text;
   text = NULL;
   return stats_text;
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart