Use VM type cast and save handles.

runtime/vm/object_store.cc

 // 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.
 
 #include "vm/object_store.h"
 
 #include "vm/exceptions.h"
 #include "vm/isolate.h"
 #include "vm/object.h"
 #include "vm/raw_object.h"
@@ skipping 92 matching lines @@
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL && isolate->object_store() == this);
   if (this->stack_overflow() != Instance::null() &&
       this->out_of_memory() != Instance::null()) {
     return true;
   }
   ASSERT(this->stack_overflow() == Instance::null());
   ASSERT(this->out_of_memory() == Instance::null());
   GrowableArray<const Object*> args;
   Object& result = Object::Handle();
-  Instance& exception = Instance::Handle();
 
   result = Exceptions::Create(Exceptions::kStackOverflow, args);
   if (result.IsError()) {
     return false;
   }
-  exception ^= result.raw();
-  set_stack_overflow(exception);
+  set_stack_overflow(Instance::Cast(result));
 
   result = Exceptions::Create(Exceptions::kOutOfMemory, args);
   if (result.IsError()) {
     return false;
   }
-  exception ^= result.raw();
-  set_out_of_memory(exception);
+  set_out_of_memory(Instance::Cast(result));
   return true;
 }
 
 
 void ObjectStore::InitKeywordTable() {
   // Set up the keywords symbol array so that we can access it while scanning.
   Array& keywords = Array::Handle(keyword_symbols());
   ASSERT(keywords.IsNull());
   keywords = Array::New(Token::numKeywords, Heap::kOld);
   ASSERT(!keywords.IsError() && !keywords.IsNull());
@@ skipping 173 matching lines @@
     return kStringInterface;
   } else if (raw_type == list_interface()) {
     return kListInterface;
   } else if (raw_type == byte_array_interface()) {
     return kByteArrayInterface;
   }
   return kInvalidIndex;
 }
 
 }  // namespace dart