Add a verification step which iterates over the heap and verifies that all canonical objects are co…

runtime/vm/verifier.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_VERIFIER_H_
 #define VM_VERIFIER_H_
 
 #include "vm/flags.h"
 #include "vm/globals.h"
 #include "vm/handles.h"
@@ skipping 63 matching lines @@
   virtual void VisitHandle(uword addr);
 
  private:
   ObjectPointerVisitor* visitor_;
 
   ObjectSet* allocated_set;
 
   DISALLOW_COPY_AND_ASSIGN(VerifyWeakPointersVisitor);
 };
 
+
+#if defined(DEBUG)
+class VerifyCanonicalVisitor : public ObjectVisitor {
+ public:
+  explicit VerifyCanonicalVisitor(Thread* thread);
+  virtual void VisitObject(RawObject* obj);
+
+ private:
+  Thread* thread_;
+  Instance& instanceHandle_;
+
+  DISALLOW_COPY_AND_ASSIGN(VerifyCanonicalVisitor);
+};
+#endif  // defined(DEBUG)
+
 }  // namespace dart
 
 #endif  // VM_VERIFIER_H_