Revert of Remove support for thread-based recompilation

src/optimizing-compile-dispatcher.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_COMPILE_DISPATCHER_H_
-#define V8_OPTIMIZING_COMPILE_DISPATCHER_H_
-
-#include <queue>
-
-#include "src/base/atomicops.h"
-#include "src/base/platform/condition-variable.h"
-#include "src/base/platform/mutex.h"
-#include "src/base/platform/platform.h"
-#include "src/flags.h"
-#include "src/list.h"
-
-namespace v8 {
-namespace internal {
-
-class HOptimizedGraphBuilder;
-class OptimizedCompileJob;
-class SharedFunctionInfo;
-
-class OptimizingCompileDispatcher {
- public:
-  explicit OptimizingCompileDispatcher(Isolate* isolate)
-      : isolate_(isolate),
-        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),
-        ref_count_(0),
-        recompilation_delay_(FLAG_concurrent_recompilation_delay) {
-    base::NoBarrier_Store(&mode_, static_cast<base::AtomicWord>(COMPILE));
-    input_queue_ = NewArray<OptimizedCompileJob*>(input_queue_capacity_);
-    if (FLAG_concurrent_osr) {
-      // Allocate and mark OSR buffer slots as empty.
-      osr_buffer_ = NewArray<OptimizedCompileJob*>(osr_buffer_capacity_);
-      for (int i = 0; i < osr_buffer_capacity_; i++) osr_buffer_[i] = NULL;
-    }
-  }
-
-  ~OptimizingCompileDispatcher();
-
-  void Run();
-  void Stop();
-  void Flush();
-  void QueueForOptimization(OptimizedCompileJob* optimizing_compiler);
-  void Unblock();
-  void InstallOptimizedFunctions();
-  OptimizedCompileJob* FindReadyOSRCandidate(Handle<JSFunction> function,
-                                             BailoutId osr_ast_id);
-  bool IsQueuedForOSR(Handle<JSFunction> function, BailoutId osr_ast_id);
-
-  bool IsQueuedForOSR(JSFunction* function);
-
-  inline bool IsQueueAvailable() {
-    base::LockGuard<base::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);
-  }
-
-  static bool Enabled(int max_available) {
-    return (FLAG_concurrent_recompilation && max_available > 1);
-  }
-
- private:
-  class CompileTask;
-
-  enum ModeFlag { COMPILE, FLUSH };
-
-  void FlushOutputQueue(bool restore_function_code);
-  void FlushOsrBuffer(bool restore_function_code);
-  void CompileNext(OptimizedCompileJob* job);
-  OptimizedCompileJob* NextInput(bool check_if_flushing = false);
-
-  // Add a recompilation task for OSR to the cyclic buffer, awaiting OSR entry.
-  // Tasks evicted from the cyclic buffer are discarded.
-  void AddToOsrBuffer(OptimizedCompileJob* compiler);
-
-  inline int InputQueueIndex(int i) {
-    int result = (i + input_queue_shift_) % input_queue_capacity_;
-    DCHECK_LE(0, result);
-    DCHECK_LT(result, input_queue_capacity_);
-    return result;
-  }
-
-  Isolate* isolate_;
-
-  // 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).
-  std::queue<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 mode_;
-
-  int osr_hits_;
-  int osr_attempts_;
-
-  int blocked_jobs_;
-
-  int ref_count_;
-  base::Mutex ref_count_mutex_;
-  base::ConditionVariable ref_count_zero_;
-
-  // Copy of FLAG_concurrent_recompilation_delay that will be used from the
-  // background thread.
-  //
-  // Since flags might get modified while the background thread is running, it
-  // is not safe to access them directly.
-  int recompilation_delay_;
-};
-}
-}  // namespace v8::internal
-
-#endif  // V8_OPTIMIZING_COMPILE_DISPATCHER_H_