Fixes bug where we would occasionally materialize a corrupted object.

runtime/vm/deferred_objects.cc

 // Copyright (c) 2013, 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/deferred_objects.h"
 
 #include "vm/deopt_instructions.h"
 #include "vm/flags.h"
 #include "vm/object.h"
 
@@ skipping 109 matching lines @@
   Field& field = Field::Handle();
   Object& value = Object::Handle();
   const Array& offset_map = Array::Handle(cls.OffsetToFieldMap());
 
   for (intptr_t i = 0; i < field_count_; i++) {
     offset ^= GetFieldOffset(i);
     field ^= offset_map.At(offset.Value() / kWordSize);
     value = GetValue(i);
     if (!field.IsNull()) {
       obj.SetField(field, value);
+      if (FLAG_trace_deoptimization_verbose) {
+        OS::PrintErr("    %s <- %s\n",
+                     String::Handle(field.name()).ToCString(),
+                     value.ToCString());
+      }
     } else {
       ASSERT(cls.IsSignatureClass() ||
              (offset.Value() == cls.type_arguments_field_offset()));
       obj.SetFieldAtOffset(offset.Value(), value);
-    }
-
-    if (FLAG_trace_deoptimization_verbose) {
-      OS::PrintErr("    %s <- %s\n",
-                   String::Handle(field.name()).ToCString(),
-                   value.ToCString());
+      if (FLAG_trace_deoptimization_verbose) {
+        OS::PrintErr("    null Field @ offset(%" Pd ") <- %s\n",
+                     offset.Value(),
+                     value.ToCString());
+      }
     }
   }
 
   object_ = &obj;
 }
 
 }  // namespace dart