Use nobarrier load in store buffer duplicate removal to annotate harmless race.

src/heap/store-buffer.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <algorithm>
 
 #include "src/v8.h"
 
 #include "src/base/atomicops.h"
 #include "src/counters.h"
@@ skipping 91 matching lines @@
 
 
 void StoreBuffer::Uniq() {
   // Remove adjacent duplicates and cells that do not point at new space.
   Address previous = NULL;
   Address* write = old_start_;
   DCHECK(may_move_store_buffer_entries_);
   for (Address* read = old_start_; read < old_top_; read++) {
     Address current = *read;
     if (current != previous) {
-      if (heap_->InNewSpace(*reinterpret_cast<Object**>(current))) {
+      Object* object = reinterpret_cast<Object*>(
+          base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(current)));
+      if (heap_->InNewSpace(object)) {
         *write++ = current;
       }
     }
     previous = current;
   }
   old_top_ = write;
 }
 
 
 bool StoreBuffer::SpaceAvailable(intptr_t space_needed) {
@@ skipping 471 matching lines @@
     }
     old_buffer_is_sorted_ = false;
     old_buffer_is_filtered_ = false;
     *old_top_++ = reinterpret_cast<Address>(int_addr << kPointerSizeLog2);
     DCHECK(old_top_ <= old_limit_);
   }
   heap_->isolate()->counters()->store_buffer_compactions()->Increment();
 }
 }
 }  // namespace v8::internal