Prevent flushing of code that was set with %SetCode.

src/runtime.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 2480 matching lines @@
   if (code->IsNull()) return *target;
   RUNTIME_ASSERT(code->IsJSFunction());
   Handle<JSFunction> source = Handle<JSFunction>::cast(code);
   Handle<SharedFunctionInfo> target_shared(target->shared());
   Handle<SharedFunctionInfo> source_shared(source->shared());
 
   if (!JSFunction::EnsureCompiled(source, KEEP_EXCEPTION)) {
     return Failure::Exception();
   }
 
+  // Mark both, the source and the target, as un-flushable because the
+  // shared unoptimized code makes them impossible to enqueue in a list.
+  ASSERT(target_shared->code()->gc_metadata() == NULL);
+  ASSERT(source_shared->code()->gc_metadata() == NULL);
+  target_shared->set_dont_flush(true);
+  source_shared->set_dont_flush(true);
+
   // Set the code, scope info, formal parameter count, and the length
   // of the target shared function info.  Set the source code of the
   // target function to undefined.  SetCode is only used for built-in
   // constructors like String, Array, and Object, and some web code
   // doesn't like seeing source code for constructors.
   target_shared->ReplaceCode(source_shared->code());
   target_shared->set_scope_info(source_shared->scope_info());
   target_shared->set_length(source_shared->length());
   target_shared->set_formal_parameter_count(
       source_shared->formal_parameter_count());
@@ skipping 10986 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal