CSE2410 Fall 2014 Bounce

// Copyright 2012 the V8 project authors. All rights reserved.

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

//

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//       notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above

//       copyright notice, this list of conditions and the following

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//       with the distribution.

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//       contributors may be used to endorse or promote products derived

//       from this software without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef V8_OPTIMIZING_COMPILER_THREAD_H_

#define V8_OPTIMIZING_COMPILER_THREAD_H_

#include "atomicops.h"

#include "flags.h"

#include "list.h"

#include "platform.h"

#include "platform/mutex.h"

#include "platform/time.h"

#include "unbound-queue-inl.h"

namespace v8 {

namespace internal {

class HOptimizedGraphBuilder;

class RecompileJob;

class SharedFunctionInfo;

class OptimizingCompilerThread : public Thread {

 public:

  explicit OptimizingCompilerThread(Isolate *isolate) :

      Thread("OptimizingCompilerThread"),

#ifdef DEBUG

      thread_id_(0),

#endif

      isolate_(isolate),

      stop_semaphore_(0),

      input_queue_semaphore_(0),

      input_queue_capacity_(FLAG_concurrent_recompilation_queue_length),

      input_queue_length_(0),

      input_queue_shift_(0),

      osr_buffer_capacity_(FLAG_concurrent_recompilation_queue_length + 4),

      osr_buffer_cursor_(0),

      osr_hits_(0),

      osr_attempts_(0),

      blocked_jobs_(0) {

    NoBarrier_Store(&stop_thread_, static_cast<AtomicWord>(CONTINUE));

    input_queue_ = NewArray<RecompileJob*>(input_queue_capacity_);

    if (FLAG_concurrent_osr) {

      // Allocate and mark OSR buffer slots as empty.

      osr_buffer_ = NewArray<RecompileJob*>(osr_buffer_capacity_);

      for (int i = 0; i < osr_buffer_capacity_; i++) osr_buffer_[i] = NULL;

    }

  }

  ~OptimizingCompilerThread();

  void Run();

  void Stop();

  void Flush();

  void QueueForOptimization(RecompileJob* optimizing_compiler);

  void Unblock();

  void InstallOptimizedFunctions();

  RecompileJob* FindReadyOSRCandidate(Handle<JSFunction> function,

                                      uint32_t osr_pc_offset);

  bool IsQueuedForOSR(Handle<JSFunction> function, uint32_t osr_pc_offset);

  bool IsQueuedForOSR(JSFunction* function);

  inline bool IsQueueAvailable() {

    LockGuard<Mutex> access_input_queue(&input_queue_mutex_);

    return input_queue_length_ < input_queue_capacity_;

  }

  inline void AgeBufferedOsrJobs() {

    // Advance cursor of the cyclic buffer to next empty slot or stale OSR job.

    // Dispose said OSR job in the latter case.  Calling this on every GC

    // should make sure that we do not hold onto stale jobs indefinitely.

    AddToOsrBuffer(NULL);

  }

#ifdef DEBUG

  bool IsOptimizerThread();

#endif

 private:

  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();

  RecompileJob* NextInput();

  // 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);

  inline int InputQueueIndex(int i) {

    int result = (i + input_queue_shift_) % input_queue_capacity_;

    ASSERT_LE(0, result);

    ASSERT_LT(result, input_queue_capacity_);

    return result;

  }

#ifdef DEBUG

  int thread_id_;

  Mutex thread_id_mutex_;

#endif

  Isolate* isolate_;

  Semaphore stop_semaphore_;

  Semaphore input_queue_semaphore_;

  // Circular queue of incoming recompilation tasks (including OSR).

  RecompileJob** input_queue_;

  int input_queue_capacity_;

  int input_queue_length_;

  int input_queue_shift_;

  Mutex input_queue_mutex_;

  // Queue of recompilation tasks ready to be installed (excluding OSR).

  UnboundQueue<RecompileJob*> output_queue_;

  // Cyclic buffer of recompilation tasks for OSR.

  RecompileJob** osr_buffer_;

  int osr_buffer_capacity_;

  int osr_buffer_cursor_;

  volatile AtomicWord stop_thread_;

  TimeDelta time_spent_compiling_;

  TimeDelta time_spent_total_;

  int osr_hits_;

  int osr_attempts_;

  int blocked_jobs_;

};

} }  // namespace v8::internal

#endif  // V8_OPTIMIZING_COMPILER_THREAD_H_