A64: Synchronize with r16993.

src/optimizing-compiler-thread.h

Index: src/optimizing-compiler-thread.h
diff --git a/src/optimizing-compiler-thread.h b/src/optimizing-compiler-thread.h
index 42317657024fbc3ced25ec8381d231225728e29c..2165a4fba20bf74bf6458941be4330fefb633554 100644
--- a/src/optimizing-compiler-thread.h
+++ b/src/optimizing-compiler-thread.h
@@ -40,7 +40,7 @@ namespace v8 {
 namespace internal {
 
 class HOptimizedGraphBuilder;
-class OptimizingCompiler;
+class RecompileJob;
 class SharedFunctionInfo;
 
 class OptimizingCompilerThread : public Thread {
@@ -53,22 +53,29 @@ class OptimizingCompilerThread : public Thread {
       isolate_(isolate),
       stop_semaphore_(0),
       input_queue_semaphore_(0),
-      osr_candidates_(2),
-      ready_for_osr_(2),
+      osr_cursor_(0),
       osr_hits_(0),
       osr_attempts_(0) {
     NoBarrier_Store(&stop_thread_, static_cast<AtomicWord>(CONTINUE));
     NoBarrier_Store(&queue_length_, static_cast<AtomicWord>(0));
+    if (FLAG_concurrent_osr) {
+      osr_buffer_size_ = FLAG_concurrent_recompilation_queue_length + 4;
+      osr_buffer_ = NewArray<RecompileJob*>(osr_buffer_size_);
+      for (int i = 0; i < osr_buffer_size_; i++) osr_buffer_[i] = NULL;
+    }
+  }
+
+  ~OptimizingCompilerThread() {
+    if (FLAG_concurrent_osr) DeleteArray(osr_buffer_);
   }
-  ~OptimizingCompilerThread() {}
 
   void Run();
   void Stop();
   void Flush();
-  void QueueForOptimization(OptimizingCompiler* optimizing_compiler);
+  void QueueForOptimization(RecompileJob* optimizing_compiler);
   void InstallOptimizedFunctions();
-  OptimizingCompiler* FindReadyOSRCandidate(Handle<JSFunction> function,
-                                            uint32_t osr_pc_offset);
+  RecompileJob* FindReadyOSRCandidate(Handle<JSFunction> function,
+                                      uint32_t osr_pc_offset);
   bool IsQueuedForOSR(Handle<JSFunction> function, uint32_t osr_pc_offset);
 
   bool IsQueuedForOSR(JSFunction* function);
@@ -94,14 +101,18 @@ class OptimizingCompilerThread : public Thread {
  private:
   enum StopFlag { CONTINUE, STOP, FLUSH };
 
-  // Remove the oldest OSR candidates that are ready so that we
-  // only have |limit| left waiting.
-  void RemoveStaleOSRCandidates(int limit = kReadyForOSRLimit);
-
   void FlushInputQueue(bool restore_function_code);
   void FlushOutputQueue(bool restore_function_code);
+  void FlushOsrBuffer(bool restore_function_code);
   void CompileNext();
 
+  // Add a recompilation task for OSR to the cyclic buffer, awaiting OSR entry.
+  // Tasks evicted from the cyclic buffer are discarded.
+  void AddToOsrBuffer(RecompileJob* compiler);
+  void AdvanceOsrCursor() {
+    osr_cursor_ = (osr_cursor_ + 1) % osr_buffer_size_;
+  }
+
 #ifdef DEBUG
   int thread_id_;
   Mutex thread_id_mutex_;
@@ -112,13 +123,16 @@ class OptimizingCompilerThread : public Thread {
   Semaphore input_queue_semaphore_;
 
   // Queue of incoming recompilation tasks (including OSR).
-  UnboundQueue<OptimizingCompiler*> input_queue_;
+  UnboundQueue<RecompileJob*> input_queue_;
   // Queue of recompilation tasks ready to be installed (excluding OSR).
-  UnboundQueue<OptimizingCompiler*> output_queue_;
-  // List of recompilation tasks for OSR in the input queue.
-  List<OptimizingCompiler*> osr_candidates_;
-  // List of recompilation tasks ready for OSR.
-  List<OptimizingCompiler*> ready_for_osr_;
+  UnboundQueue<RecompileJob*> output_queue_;
+  // Cyclic buffer of recompilation tasks for OSR.
+  // TODO(yangguo): This may keep zombie tasks indefinitely, holding on to
+  //                a lot of memory.  Fix this.
+  RecompileJob** osr_buffer_;
+  // Cursor for the cyclic buffer.
+  int osr_cursor_;
+  int osr_buffer_size_;
 
   volatile AtomicWord stop_thread_;
   volatile Atomic32 queue_length_;
@@ -127,11 +141,8 @@ class OptimizingCompilerThread : public Thread {
 
   // TODO(yangguo): remove this once the memory leak has been figured out.
   Mutex queue_mutex_;
-  Mutex osr_list_mutex_;
   int osr_hits_;
   int osr_attempts_;
-
-  static const int kReadyForOSRLimit = 4;
 };
 
 } }  // namespace v8::internal