Avoid reading RawObject::class_ directly in the runtime.

runtime/vm/raw_object.h

 // 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.
 
 #ifndef VM_RAW_OBJECT_H_
 #define VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/globals.h"
 #include "vm/token.h"
@@ skipping 317 matching lines @@
   RawObject* ptr() const {
     ASSERT(IsHeapObject());
     return reinterpret_cast<RawObject*>(
         reinterpret_cast<uword>(this) - kHeapObjectTag);
   }
 
   intptr_t SizeFromClass() const;
 
   intptr_t GetClassIndex() const {
     uword tags = ptr()->tags_;
+    ASSERT(!FreeBit::decode(tags));

[Ivan Posva, 2012/06/01 16:31:06]

Please mark this with a TODO that we need to revisit this once we give the free
list elements a different layout.

     return ClassTag::decode(tags);
   }
 
   friend class Api;
   friend class Array;
   friend class Heap;
   friend class MarkingVisitor;
   friend class Object;
   friend class RawInstructions;
+  friend class RawInstance;
   friend class SnapshotReader;
   friend class SnapshotWriter;
 
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(RawObject);
 };
 
 
 class RawClass : public RawObject {
  public:
@@ skipping 1138 matching lines @@
          kExternalUint64Array == kByteArray + 18 &&
          kExternalFloat32Array == kByteArray + 19 &&
          kExternalFloat64Array == kByteArray + 20 &&
          kClosure == kByteArray + 21);
   return (index >= kByteArray && index <= kClosure);
 }
 
 }  // namespace dart
 
 #endif  // VM_RAW_OBJECT_H_