Add mutex when accessing concurrent recompilation output queue.

src/optimizing-compiler-thread.cc

Index: src/optimizing-compiler-thread.cc
diff --git a/src/optimizing-compiler-thread.cc b/src/optimizing-compiler-thread.cc
index 085143d99839e353b15b7793e606c05b78eff66f..8d5e16636d267cf33915635d8fd65e6e2d40e92a 100644
--- a/src/optimizing-compiler-thread.cc
+++ b/src/optimizing-compiler-thread.cc
@@ -74,7 +74,6 @@ void OptimizingCompilerThread::Run() {
         { AllowHandleDereference allow_handle_dereference;
           FlushInputQueue(true);
         }
-        Release_Store(&queue_length_, static_cast<AtomicWord>(0));
         Release_Store(&stop_thread_, static_cast<AtomicWord>(CONTINUE));
         stop_semaphore_.Signal();
         // Return to start of consumer loop.
@@ -114,6 +113,7 @@ void OptimizingCompilerThread::CompileNext() {
     osr_candidates_.RemoveElement(optimizing_compiler);
     ready_for_osr_.Add(optimizing_compiler);
   } else {
+    LockGuard<Mutex> access_queue(&queue_mutex_);
     output_queue_.Enqueue(optimizing_compiler);
     isolate_->stack_guard()->RequestInstallCode();
   }
@@ -134,13 +134,20 @@ void OptimizingCompilerThread::FlushInputQueue(bool restore_function_code) {
     }
     delete info;
   }
+  Release_Store(&queue_length_, static_cast<AtomicWord>(0));
+
+  LockGuard<Mutex> access_osr_lists(&osr_list_mutex_);
+  osr_candidates_.Clear();
 }
 
 
 void OptimizingCompilerThread::FlushOutputQueue(bool restore_function_code) {
   OptimizingCompiler* optimizing_compiler;
   // The optimizing compiler is allocated in the CompilationInfo's zone.
-  while (output_queue_.Dequeue(&optimizing_compiler)) {
+  while (true) {
+    { LockGuard<Mutex> access_queue(&queue_mutex_);
+      if (!output_queue_.Dequeue(&optimizing_compiler)) break;
+    }
     CompilationInfo* info = optimizing_compiler->info();
     if (restore_function_code) {
       Handle<JSFunction> function = info->closure();
@@ -149,7 +156,6 @@ void OptimizingCompilerThread::FlushOutputQueue(bool restore_function_code) {
     delete info;
   }
 
-  osr_candidates_.Clear();
   RemoveStaleOSRCandidates(0);
 }
 
@@ -196,9 +202,12 @@ void OptimizingCompilerThread::Stop() {
 void OptimizingCompilerThread::InstallOptimizedFunctions() {
   ASSERT(!IsOptimizerThread());
   HandleScope handle_scope(isolate_);
+
   OptimizingCompiler* compiler;
   while (true) {
-    if (!output_queue_.Dequeue(&compiler)) return;
+    { LockGuard<Mutex> access_queue(&queue_mutex_);
+      if (!output_queue_.Dequeue(&optimizing_compiler)) break;
+    }
     Compiler::InstallOptimizedCode(compiler);
   }