Improve trace_opt output to help find compilation problems

src/objects-visiting-inl.h

 // 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 298 matching lines @@
   Heap* heap = map->GetHeap();
   SharedFunctionInfo* shared = SharedFunctionInfo::cast(object);
   if (shared->ic_age() != heap->global_ic_age()) {
     shared->ResetForNewContext(heap->global_ic_age());
   }
   if (FLAG_cache_optimized_code) {
     // Flush optimized code map on major GC.
     // TODO(mstarzinger): We may experiment with rebuilding it or with
     // retaining entries which should survive as we iterate through
     // optimized functions anyway.
-    shared->ClearOptimizedCodeMap();
+    shared->ClearOptimizedCodeMap("during full gc");
   }
   MarkCompactCollector* collector = heap->mark_compact_collector();
   if (collector->is_code_flushing_enabled()) {
     if (IsFlushable(heap, shared)) {
       // This function's code looks flushable. But we have to postpone
       // the decision until we see all functions that point to the same
       // SharedFunctionInfo because some of them might be optimized.
       // That would also make the non-optimized version of the code
       // non-flushable, because it is required for bailing out from
       // optimized code.
@@ skipping 395 matching lines @@
   RelocIterator it(this, mode_mask);
   for (; !it.done(); it.next()) {
     it.rinfo()->template Visit<StaticVisitor>(heap);
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_VISITING_INL_H_