Fix TSAN issue wrt assertions in the optimizing compiler thread.

src/hydrogen-environment-liveness.cc

 // Copyright 2013 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 66 matching lines @@
     BitVector* live_in_successor = live_at_block_start_[successor_id];
     if (live_in_successor->Equals(*live)) continue;
     for (int i = 0; i < live->length(); ++i) {
       if (!live->Contains(i)) continue;
       if (live_in_successor->Contains(i)) continue;
       if (first_simulate_invalid_for_index_.at(successor_id)->Contains(i)) {
         continue;
       }
       HSimulate* simulate = first_simulate_.at(successor_id);
       if (simulate == NULL) continue;
-      ASSERT(simulate->closure().is_identical_to(
-                 block->last_environment()->closure()));
+      ASSERT(VerifyClosures(simulate->closure(),
+          block->last_environment()->closure()));
       ZapEnvironmentSlot(i, simulate);
     }
   }
 }
 
 
 void HEnvironmentLivenessAnalysisPhase::ZapEnvironmentSlotsForInstruction(
     HEnvironmentMarker* marker) {
   if (!marker->CheckFlag(HValue::kEndsLiveRange)) return;
   HSimulate* simulate = marker->next_simulate();
   if (simulate != NULL) {
-    ASSERT(simulate->closure().is_identical_to(marker->closure()));
+    ASSERT(VerifyClosures(simulate->closure(), marker->closure()));
     ZapEnvironmentSlot(marker->index(), simulate);
   }
 }
 
 
 void HEnvironmentLivenessAnalysisPhase::UpdateLivenessAtBlockEnd(
     HBasicBlock* block,
     BitVector* live) {
   // Liveness at the end of each block: union of liveness in successors.
   live->Clear();
@@ skipping 123 matching lines @@
     UpdateLivenessAtBlockEnd(block, &live);
     ZapEnvironmentSlotsInSuccessors(block, &live);
   }
 
   // Finally, remove the HEnvironment{Bind,Lookup} markers.
   for (int i = 0; i < markers_.length(); ++i) {
     markers_[i]->DeleteAndReplaceWith(NULL);
   }
 }
 
+
+#ifdef DEBUG
+bool HEnvironmentLivenessAnalysisPhase::VerifyClosures(
+    Handle<JSFunction> a, Handle<JSFunction> b) {
+  Heap::RelocationLock for_heap_access(isolate()->heap());
+  AllowHandleDereference for_verification;
+  return a.is_identical_to(b);
+}
+#endif
+
 } }  // namespace v8::internal