Introduce --job-based-recompilation flag

src/optimizing-compiler-thread.h

 // Copyright 2012 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.
 
 #ifndef V8_OPTIMIZING_COMPILER_THREAD_H_
 #define V8_OPTIMIZING_COMPILER_THREAD_H_
 
 #include "src/base/atomicops.h"
 #include "src/base/platform/mutex.h"
 #include "src/base/platform/platform.h"
@@ skipping 66 matching lines @@
   static bool Enabled(int max_available) {
     return (FLAG_concurrent_recompilation && max_available > 1);
   }
 
 #ifdef DEBUG
   static bool IsOptimizerThread(Isolate* isolate);
   bool IsOptimizerThread();
 #endif
 
  private:
+  class CompileTask;
+
   enum StopFlag { CONTINUE, STOP, FLUSH };
 
   void FlushInputQueue(bool restore_function_code);
   void FlushOutputQueue(bool restore_function_code);
   void FlushOsrBuffer(bool restore_function_code);
   void CompileNext();
   OptimizedCompileJob* NextInput();
 
   // Add a recompilation task for OSR to the cyclic buffer, awaiting OSR entry.
   // Tasks evicted from the cyclic buffer are discarded.
@@ skipping 17 matching lines @@
 
   // Circular queue of incoming recompilation tasks (including OSR).
   OptimizedCompileJob** input_queue_;
   int input_queue_capacity_;
   int input_queue_length_;
   int input_queue_shift_;
   base::Mutex input_queue_mutex_;
 
   // Queue of recompilation tasks ready to be installed (excluding OSR).
   UnboundQueue<OptimizedCompileJob*> output_queue_;
+  // Used for job based recompilation which has multiple producers on
+  // different threads.
+  base::Mutex output_queue_mutex_;
 
   // Cyclic buffer of recompilation tasks for OSR.
   OptimizedCompileJob** osr_buffer_;
   int osr_buffer_capacity_;
   int osr_buffer_cursor_;
 
   volatile base::AtomicWord stop_thread_;
   base::TimeDelta time_spent_compiling_;
   base::TimeDelta time_spent_total_;
 
   int osr_hits_;
   int osr_attempts_;
 
   int blocked_jobs_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OPTIMIZING_COMPILER_THREAD_H_