Create read only handles for empty_array and sentinel objects

vm/intermediate_language.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/intermediate_language.h"
 
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 131 matching lines @@
            (ResultCid() == kDynamicCid) ||
            (other_load->ResultCid() == kDynamicCid))));
   return offset_in_bytes() == other_load->offset_in_bytes();
 }
 
 
 bool LoadStaticFieldInstr::AttributesEqual(Instruction* other) const {
   LoadStaticFieldInstr* other_load = other->AsLoadStaticField();
   ASSERT(other_load != NULL);
   // Assert that the field is initialized.
-  ASSERT(field().value() != Object::sentinel());
-  ASSERT(field().value() != Object::transition_sentinel());
+  ASSERT(field().value() != Object::sentinel().raw());
+  ASSERT(field().value() != Object::transition_sentinel().raw());
   return field().raw() == other_load->field().raw();
 }
 
 
 bool StringCharCodeAtInstr::AttributesEqual(Instruction* other) const {
   StringCharCodeAtInstr* other_load = other->AsStringCharCodeAt();
   ASSERT(other_load != NULL);
   return class_id() == other_load->class_id();
 }
 
@@ skipping 2608 matching lines @@
     default:
       UNREACHABLE();
       return -1;
   }
 }
 
 
 #undef __
 
 }  // namespace dart