Fix TSAN issue wrt assertions in the optimizing compiler thread.

src/hydrogen-environment-liveness.cc

Index: src/hydrogen-environment-liveness.cc
diff --git a/src/hydrogen-environment-liveness.cc b/src/hydrogen-environment-liveness.cc
index d7501ac49e6fd2b519a1471a1f6d88543410d16d..d37731f12d9379c52a5b739cf682a9ad8b434d38 100644
--- a/src/hydrogen-environment-liveness.cc
+++ b/src/hydrogen-environment-liveness.cc
@@ -84,8 +84,10 @@ void HEnvironmentLivenessAnalysisPhase::ZapEnvironmentSlotsInSuccessors(
       }
       HSimulate* simulate = first_simulate_.at(successor_id);
       if (simulate == NULL) continue;
-      ASSERT(simulate->closure().is_identical_to(
-                 block->last_environment()->closure()));
+      { AllowHandleDereference locked;
+        ASSERT(simulate->closure().is_identical_to(
+                   block->last_environment()->closure()));
+      }
       ZapEnvironmentSlot(i, simulate);
     }
   }
@@ -97,7 +99,9 @@ void HEnvironmentLivenessAnalysisPhase::ZapEnvironmentSlotsForInstruction(
   if (!marker->CheckFlag(HValue::kEndsLiveRange)) return;
   HSimulate* simulate = marker->next_simulate();
   if (simulate != NULL) {
-    ASSERT(simulate->closure().is_identical_to(marker->closure()));
+    { AllowHandleDereference locked;
+      ASSERT(simulate->closure().is_identical_to(marker->closure()));
+    }
     ZapEnvironmentSlot(marker->index(), simulate);
   }
 }
@@ -227,11 +231,18 @@ void HEnvironmentLivenessAnalysisPhase::Run() {
 
   // Analysis finished. Zap dead environment slots.
   for (int i = 0; i < markers_.length(); ++i) {
+    // Acquire relocation lock to dereference for assertion.
+#ifdef DEBUG
+    Heap::RelocationLock for_heap_access(isolate()->heap());

[Hannes Payer (out of office), 2014/03/27 17:16:20]

what about moving that locking code to where it is needed, i.e.
ZapEnvironmentSlotsForInstruction?

[Yang, 2014/03/28 08:27:40]

I refactored the handle comparison.

+#endif
     ZapEnvironmentSlotsForInstruction(markers_[i]);
   }
   for (int block_id = block_count_ - 1; block_id >= 0; --block_id) {
     HBasicBlock* block = graph()->blocks()->at(block_id);
     UpdateLivenessAtBlockEnd(block, &live);
+#ifdef DEBUG
+    Heap::RelocationLock for_heap_access(isolate()->heap());

[Hannes Payer (out of office), 2014/03/27 17:16:20]

what about moving that locking code to where it is needed, i.e.
ZapEnvironmentSlotsInSuccessors?

+#endif
     ZapEnvironmentSlotsInSuccessors(block, &live);
   }