From 3579968e865abd3af110ccc892b06b18f05b2a7c Mon Sep 17 00:00:00 2001
From: "yangguo@chromium.org"
 <yangguo@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Fri, 28 Mar 2014 08:49:58 +0000
Subject: [PATCH] Fix TSAN issue wrt assertions in the optimizing compiler
 thread.

R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/212603013

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20322 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/handles-inl.h                    | 13 +++++++------
 src/hydrogen-environment-liveness.cc | 16 +++++++++++++---
 src/hydrogen-environment-liveness.h  |  3 +++
 3 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/src/handles-inl.h b/src/handles-inl.h
index a25b4a2..19a02cc 100644
--- a/src/handles-inl.h
+++ b/src/handles-inl.h
@@ -52,14 +52,15 @@ Handle<T>::Handle(T* obj, Isolate* isolate) {
 
 
 template <typename T>
-inline bool Handle<T>::is_identical_to(const Handle<T> other) const {
+inline bool Handle<T>::is_identical_to(const Handle<T> o) const {
   ASSERT(location_ == NULL || !(*location_)->IsFailure());
-  if (location_ == other.location_) return true;
-  if (location_ == NULL || other.location_ == NULL) return false;
   // Dereferencing deferred handles to check object equality is safe.
-  SLOW_ASSERT(IsDereferenceAllowed(NO_DEFERRED_CHECK) &&
-              other.IsDereferenceAllowed(NO_DEFERRED_CHECK));
-  return *location_ == *other.location_;
+  SLOW_ASSERT(
+      (location_ == NULL || IsDereferenceAllowed(NO_DEFERRED_CHECK)) &&
+      (o.location_ == NULL || o.IsDereferenceAllowed(NO_DEFERRED_CHECK)));
+  if (location_ == o.location_) return true;
+  if (location_ == NULL || o.location_ == NULL) return false;
+  return *location_ == *o.location_;
 }
 
 
diff --git a/src/hydrogen-environment-liveness.cc b/src/hydrogen-environment-liveness.cc
index d7501ac..726198d 100644
--- a/src/hydrogen-environment-liveness.cc
+++ b/src/hydrogen-environment-liveness.cc
@@ -84,8 +84,8 @@ void HEnvironmentLivenessAnalysisPhase::ZapEnvironmentSlotsInSuccessors(
       }
       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);
     }
   }
@@ -97,7 +97,7 @@ 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()));
+    ASSERT(VerifyClosures(simulate->closure(), marker->closure()));
     ZapEnvironmentSlot(marker->index(), simulate);
   }
 }
@@ -241,4 +241,14 @@ void HEnvironmentLivenessAnalysisPhase::Run() {
   }
 }
 
+
+#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
diff --git a/src/hydrogen-environment-liveness.h b/src/hydrogen-environment-liveness.h
index 248ec5c..6ad02d7 100644
--- a/src/hydrogen-environment-liveness.h
+++ b/src/hydrogen-environment-liveness.h
@@ -55,6 +55,9 @@ class HEnvironmentLivenessAnalysisPhase : public HPhase {
   void ZapEnvironmentSlotsForInstruction(HEnvironmentMarker* marker);
   void UpdateLivenessAtBlockEnd(HBasicBlock* block, BitVector* live);
   void UpdateLivenessAtInstruction(HInstruction* instr, BitVector* live);
+#ifdef DEBUG
+  bool VerifyClosures(Handle<JSFunction> a, Handle<JSFunction> b);
+#endif
 
   int block_count_;
 
-- 
2.7.4