Avoid handle dereference during graph optimization.

src/isolate.cc

 // Copyright 2012 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 1659 matching lines @@
   simulator_initialized_ = false;
   simulator_i_cache_ = NULL;
   simulator_redirection_ = NULL;
 #endif
 
 #ifdef DEBUG
   // heap_histograms_ initializes itself.
   memset(&js_spill_information_, 0, sizeof(js_spill_information_));
   memset(code_kind_statistics_, 0,
          sizeof(code_kind_statistics_[0]) * Code::NUMBER_OF_KINDS);
+
+  allow_handle_deref_ = true;
 #endif
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
   debug_ = NULL;
   debugger_ = NULL;
 #endif
 
   handle_scope_data_.Initialize();
 
 #define ISOLATE_INIT_EXECUTE(type, name, initial_value)                        \
@@ skipping 525 matching lines @@
 
 #ifdef DEBUG
 #define ISOLATE_FIELD_OFFSET(type, name, ignored)                       \
 const intptr_t Isolate::name##_debug_offset_ = OFFSET_OF(Isolate, name##_);
 ISOLATE_INIT_LIST(ISOLATE_FIELD_OFFSET)
 ISOLATE_INIT_ARRAY_LIST(ISOLATE_FIELD_OFFSET)
 #undef ISOLATE_FIELD_OFFSET
 #endif
 
 } }  // namespace v8::internal