Fix compile failure from revision 6934 and win64 compile failure from revisio...

src/runtime.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 8256 matching lines @@
             ExternalUnsignedIntArray::cast(object->elements())->length();
           break;
         }
         case JSObject::EXTERNAL_FLOAT_ELEMENTS: {
         dense_elements_length =
             ExternalFloatArray::cast(object->elements())->length();
           break;
         }
         default:
           UNREACHABLE();
+          dense_elements_length = 0;
           break;
       }
       uint32_t length = static_cast<uint32_t>(dense_elements_length);
       if (range <= length) {
         length = range;
         // We will add all indices, so we might as well clear it first
         // and avoid duplicates.
         indices->Clear();
       }
       for (uint32_t i = 0; i < length; i++) {
@@ skipping 3004 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal