Disallow dereferencing deferred handles when generating optimized code.

src/compiler.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 407 matching lines @@
   return SetLastStatus(SUCCEEDED);
 }
 
 
 OptimizingCompiler::Status OptimizingCompiler::GenerateAndInstallCode() {
   ASSERT(last_status() == SUCCEEDED);
   {  // Scope for timer.
     Timer timer(this, &time_taken_to_codegen_);
     ASSERT(chunk_ != NULL);
     ASSERT(graph_ != NULL);
+    // Deferred handles reference objects that were accessible during
+    // graph creation.  To make sure that we don't encounter inconsistencies
+    // between graph creation and code generation, we disallow accessing
+    // objects through deferred handles during the latter, with exceptions.
+    HandleDereferenceGuard no_deref_deferred(
+        isolate(), HandleDereferenceGuard::DISALLOW_DEFERRED);
     Handle<Code> optimized_code = chunk_->Codegen();
     if (optimized_code.is_null()) {
       info()->set_bailout_reason("code generation failed");
       return AbortOptimization();
     }
     info()->SetCode(optimized_code);
   }
   RecordOptimizationStats();
   return SetLastStatus(SUCCEEDED);
 }
@@ skipping 727 matching lines @@
     }
   }
 
   GDBJIT(AddCode(Handle<String>(shared->DebugName()),
                  Handle<Script>(info->script()),
                  Handle<Code>(info->code()),
                  info));
 }
 
 } }  // namespace v8::internal