Symbols for type cells.

src/full-codegen.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 370 matching lines @@
     __ dd(back_edges_[i].id.ToInt());
     __ dd(back_edges_[i].pc);
     __ dd(back_edges_[i].loop_depth);
   }
   return offset;
 }
 
 
 void FullCodeGenerator::InitializeFeedbackVector() {
   int length = info_->function()->slot_count();
-  ASSERT_EQ(isolate()->heap()->the_hole_value(),
-            *TypeFeedbackInfo::UninitializedSentinel(isolate()));
-  feedback_vector_ = isolate()->factory()->NewFixedArrayWithHoles(length,
-                                                                  TENURED);
+  feedback_vector_ = isolate()->factory()->NewFixedArray(length, TENURED);
+  Handle<Object> sentinel = TypeFeedbackInfo::UninitializedSentinel(isolate());
+  // Ensure that it's safe to set without using a write barrier.
+  ASSERT_EQ(isolate()->heap()->uninitialized_symbol(), *sentinel);
+  for (int i = 0; i < length; i++) {
+    feedback_vector_->set(i, *sentinel, SKIP_WRITE_BARRIER);
+  }
 }
 
 
 void FullCodeGenerator::PopulateDeoptimizationData(Handle<Code> code) {
   // Fill in the deoptimization information.
   ASSERT(info_->HasDeoptimizationSupport() || bailout_entries_.is_empty());
   if (!info_->HasDeoptimizationSupport()) return;
   int length = bailout_entries_.length();
   Handle<DeoptimizationOutputData> data = isolate()->factory()->
       NewDeoptimizationOutputData(length, TENURED);
@@ skipping 1323 matching lines @@
   }
   return true;
 }
 #endif  // DEBUG
 
 
 #undef __
 
 
 } }  // namespace v8::internal