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

runtime/vm/verifier.cc

 // Copyright (c) 2012, 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/verifier.h"
 
 #include "platform/assert.h"
 #include "vm/dart.h"
 #include "vm/dart_api_state.h"
 #include "vm/freelist.h"
@@ skipping 64 matching lines @@
   VerifyPointersVisitor visitor(isolate, allocated_set);
   // Visit all strongly reachable objects.
   isolate->IterateObjectPointers(&visitor,
                                  StackFrameIterator::kValidateFrames);
   VerifyWeakPointersVisitor weak_visitor(&visitor);
   // Visit weak handles and prologue weak handles.
   isolate->VisitWeakPersistentHandles(&weak_visitor);
   delete allocated_set;
 }
 
+
+#if defined(DEBUG)
+VerifyCanonicalVisitor::VerifyCanonicalVisitor(Thread* thread)
+    : thread_(thread),
+      instanceHandle_(Instance::Handle(thread->zone())) {
+}
+
+
+void VerifyCanonicalVisitor::VisitObject(RawObject* obj) {
+  if (obj->GetClassId() >= kInstanceCid) {
+    if (obj->IsCanonical()) {
+      instanceHandle_ ^= obj;
+      ASSERT(instanceHandle_.CheckIsCanonical(thread_));
+    }
+  }
+}
+#endif  // defined(DEBUG)
+
 }  // namespace dart