diff --git a/src/optimizing-compile-dispatcher.cc b/src/optimizing-compile-dispatcher.cc
new file mode 100644
index 0000000..7062db6
--- /dev/null
+++ b/src/optimizing-compile-dispatcher.cc
@@ -0,0 +1,358 @@
+// 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.
+
+#include "src/optimizing-compile-dispatcher.h"
+
+#include "src/base/atomicops.h"
+#include "src/full-codegen/full-codegen.h"
+#include "src/isolate.h"
+#include "src/v8.h"
+
+namespace v8 {
+namespace internal {
+
+namespace {
+
+void DisposeOptimizedCompileJob(OptimizedCompileJob* job,
+                                bool restore_function_code) {
+  // The recompile job is allocated in the CompilationInfo's zone.
+  CompilationInfo* info = job->info();
+  if (restore_function_code) {
+    if (info->is_osr()) {
+      if (!job->IsWaitingForInstall()) {
+        // Remove stack check that guards OSR entry on original code.
+        Handle<Code> code = info->unoptimized_code();
+        uint32_t offset = code->TranslateAstIdToPcOffset(info->osr_ast_id());
+        BackEdgeTable::RemoveStackCheck(code, offset);
+      }
+    } else {
+      Handle<JSFunction> function = info->closure();
+      function->ReplaceCode(function->shared()->code());
+    }
+  }
+  delete info;
+}
+
+}  // namespace
+
+
+class OptimizingCompileDispatcher::CompileTask : public v8::Task {
+ public:
+  explicit CompileTask(Isolate* isolate) : isolate_(isolate) {
+    OptimizingCompileDispatcher* dispatcher =
+        isolate_->optimizing_compile_dispatcher();
+    base::LockGuard<base::Mutex> lock_guard(&dispatcher->ref_count_mutex_);
+    ++dispatcher->ref_count_;
+  }
+
+  virtual ~CompileTask() {}
+
+ private:
+  // v8::Task overrides.
+  void Run() override {
+    DisallowHeapAllocation no_allocation;
+    DisallowHandleAllocation no_handles;
+    DisallowHandleDereference no_deref;
+
+    OptimizingCompileDispatcher* dispatcher =
+        isolate_->optimizing_compile_dispatcher();
+    {
+      TimerEventScope<TimerEventRecompileConcurrent> timer(isolate_);
+
+      if (dispatcher->recompilation_delay_ != 0) {
+        base::OS::Sleep(base::TimeDelta::FromMilliseconds(
+            dispatcher->recompilation_delay_));
+      }
+
+      dispatcher->CompileNext(dispatcher->NextInput(true));
+    }
+    {
+      base::LockGuard<base::Mutex> lock_guard(&dispatcher->ref_count_mutex_);
+      if (--dispatcher->ref_count_ == 0) {
+        dispatcher->ref_count_zero_.NotifyOne();
+      }
+    }
+  }
+
+  Isolate* isolate_;
+
+  DISALLOW_COPY_AND_ASSIGN(CompileTask);
+};
+
+
+OptimizingCompileDispatcher::~OptimizingCompileDispatcher() {
+#ifdef DEBUG
+  {
+    base::LockGuard<base::Mutex> lock_guard(&ref_count_mutex_);
+    DCHECK_EQ(0, ref_count_);
+  }
+#endif
+  DCHECK_EQ(0, input_queue_length_);
+  DeleteArray(input_queue_);
+  if (FLAG_concurrent_osr) {
+#ifdef DEBUG
+    for (int i = 0; i < osr_buffer_capacity_; i++) {
+      CHECK_NULL(osr_buffer_[i]);
+    }
+#endif
+    DeleteArray(osr_buffer_);
+  }
+}
+
+
+OptimizedCompileJob* OptimizingCompileDispatcher::NextInput(
+    bool check_if_flushing) {
+  base::LockGuard<base::Mutex> access_input_queue_(&input_queue_mutex_);
+  if (input_queue_length_ == 0) return NULL;
+  OptimizedCompileJob* job = input_queue_[InputQueueIndex(0)];
+  DCHECK_NOT_NULL(job);
+  input_queue_shift_ = InputQueueIndex(1);
+  input_queue_length_--;
+  if (check_if_flushing) {
+    if (static_cast<ModeFlag>(base::Acquire_Load(&mode_)) == FLUSH) {
+      if (!job->info()->is_osr()) {
+        AllowHandleDereference allow_handle_dereference;
+        DisposeOptimizedCompileJob(job, true);
+      }
+      return NULL;
+    }
+  }
+  return job;
+}
+
+
+void OptimizingCompileDispatcher::CompileNext(OptimizedCompileJob* job) {
+  if (!job) return;
+
+  // The function may have already been optimized by OSR.  Simply continue.
+  OptimizedCompileJob::Status status = job->OptimizeGraph();
+  USE(status);  // Prevent an unused-variable error in release mode.
+  DCHECK(status != OptimizedCompileJob::FAILED);
+
+  // The function may have already been optimized by OSR.  Simply continue.
+  // Use a mutex to make sure that functions marked for install
+  // are always also queued.
+  base::LockGuard<base::Mutex> access_output_queue_(&output_queue_mutex_);
+  output_queue_.push(job);
+  isolate_->stack_guard()->RequestInstallCode();
+}
+
+
+void OptimizingCompileDispatcher::FlushOutputQueue(bool restore_function_code) {
+  for (;;) {
+    OptimizedCompileJob* job = NULL;
+    {
+      base::LockGuard<base::Mutex> access_output_queue_(&output_queue_mutex_);
+      if (output_queue_.empty()) return;
+      job = output_queue_.front();
+      output_queue_.pop();
+    }
+
+    // OSR jobs are dealt with separately.
+    if (!job->info()->is_osr()) {
+      DisposeOptimizedCompileJob(job, restore_function_code);
+    }
+  }
+}
+
+
+void OptimizingCompileDispatcher::FlushOsrBuffer(bool restore_function_code) {
+  for (int i = 0; i < osr_buffer_capacity_; i++) {
+    if (osr_buffer_[i] != NULL) {
+      DisposeOptimizedCompileJob(osr_buffer_[i], restore_function_code);
+      osr_buffer_[i] = NULL;
+    }
+  }
+}
+
+
+void OptimizingCompileDispatcher::Flush() {
+  base::Release_Store(&mode_, static_cast<base::AtomicWord>(FLUSH));
+  if (FLAG_block_concurrent_recompilation) Unblock();
+  {
+    base::LockGuard<base::Mutex> lock_guard(&ref_count_mutex_);
+    while (ref_count_ > 0) ref_count_zero_.Wait(&ref_count_mutex_);
+    base::Release_Store(&mode_, static_cast<base::AtomicWord>(COMPILE));
+  }
+  FlushOutputQueue(true);
+  if (FLAG_concurrent_osr) FlushOsrBuffer(true);
+  if (FLAG_trace_concurrent_recompilation) {
+    PrintF("  ** Flushed concurrent recompilation queues.\n");
+  }
+}
+
+
+void OptimizingCompileDispatcher::Stop() {
+  base::Release_Store(&mode_, static_cast<base::AtomicWord>(FLUSH));
+  if (FLAG_block_concurrent_recompilation) Unblock();
+  {
+    base::LockGuard<base::Mutex> lock_guard(&ref_count_mutex_);
+    while (ref_count_ > 0) ref_count_zero_.Wait(&ref_count_mutex_);
+    base::Release_Store(&mode_, static_cast<base::AtomicWord>(COMPILE));
+  }
+
+  if (recompilation_delay_ != 0) {
+    // At this point the optimizing compiler thread's event loop has stopped.
+    // There is no need for a mutex when reading input_queue_length_.
+    while (input_queue_length_ > 0) CompileNext(NextInput());
+    InstallOptimizedFunctions();
+  } else {
+    FlushOutputQueue(false);
+  }
+
+  if (FLAG_concurrent_osr) FlushOsrBuffer(false);
+
+  if ((FLAG_trace_osr || FLAG_trace_concurrent_recompilation) &&
+      FLAG_concurrent_osr) {
+    PrintF("[COSR hit rate %d / %d]\n", osr_hits_, osr_attempts_);
+  }
+}
+
+
+void OptimizingCompileDispatcher::InstallOptimizedFunctions() {
+  HandleScope handle_scope(isolate_);
+
+  for (;;) {
+    OptimizedCompileJob* job = NULL;
+    {
+      base::LockGuard<base::Mutex> access_output_queue_(&output_queue_mutex_);
+      if (output_queue_.empty()) return;
+      job = output_queue_.front();
+      output_queue_.pop();
+    }
+    CompilationInfo* info = job->info();
+    Handle<JSFunction> function(*info->closure());
+    if (info->is_osr()) {
+      if (FLAG_trace_osr) {
+        PrintF("[COSR - ");
+        function->ShortPrint();
+        PrintF(" is ready for install and entry at AST id %d]\n",
+               info->osr_ast_id().ToInt());
+      }
+      job->WaitForInstall();
+      // Remove stack check that guards OSR entry on original code.
+      Handle<Code> code = info->unoptimized_code();
+      uint32_t offset = code->TranslateAstIdToPcOffset(info->osr_ast_id());
+      BackEdgeTable::RemoveStackCheck(code, offset);
+    } else {
+      if (function->IsOptimized()) {
+        if (FLAG_trace_concurrent_recompilation) {
+          PrintF("  ** Aborting compilation for ");
+          function->ShortPrint();
+          PrintF(" as it has already been optimized.\n");
+        }
+        DisposeOptimizedCompileJob(job, false);
+      } else {
+        Handle<Code> code = Compiler::GetConcurrentlyOptimizedCode(job);
+        function->ReplaceCode(code.is_null() ? function->shared()->code()
+                                             : *code);
+      }
+    }
+  }
+}
+
+
+void OptimizingCompileDispatcher::QueueForOptimization(
+    OptimizedCompileJob* job) {
+  DCHECK(IsQueueAvailable());
+  CompilationInfo* info = job->info();
+  if (info->is_osr()) {
+    osr_attempts_++;
+    AddToOsrBuffer(job);
+    // Add job to the front of the input queue.
+    base::LockGuard<base::Mutex> access_input_queue(&input_queue_mutex_);
+    DCHECK_LT(input_queue_length_, input_queue_capacity_);
+    // Move shift_ back by one.
+    input_queue_shift_ = InputQueueIndex(input_queue_capacity_ - 1);
+    input_queue_[InputQueueIndex(0)] = job;
+    input_queue_length_++;
+  } else {
+    // Add job to the back of the input queue.
+    base::LockGuard<base::Mutex> access_input_queue(&input_queue_mutex_);
+    DCHECK_LT(input_queue_length_, input_queue_capacity_);
+    input_queue_[InputQueueIndex(input_queue_length_)] = job;
+    input_queue_length_++;
+  }
+  if (FLAG_block_concurrent_recompilation) {
+    blocked_jobs_++;
+  } else {
+    V8::GetCurrentPlatform()->CallOnBackgroundThread(
+        new CompileTask(isolate_), v8::Platform::kShortRunningTask);
+  }
+}
+
+
+void OptimizingCompileDispatcher::Unblock() {
+  while (blocked_jobs_ > 0) {
+    V8::GetCurrentPlatform()->CallOnBackgroundThread(
+        new CompileTask(isolate_), v8::Platform::kShortRunningTask);
+    blocked_jobs_--;
+  }
+}
+
+
+OptimizedCompileJob* OptimizingCompileDispatcher::FindReadyOSRCandidate(
+    Handle<JSFunction> function, BailoutId osr_ast_id) {
+  for (int i = 0; i < osr_buffer_capacity_; i++) {
+    OptimizedCompileJob* current = osr_buffer_[i];
+    if (current != NULL && current->IsWaitingForInstall() &&
+        current->info()->HasSameOsrEntry(function, osr_ast_id)) {
+      osr_hits_++;
+      osr_buffer_[i] = NULL;
+      return current;
+    }
+  }
+  return NULL;
+}
+
+
+bool OptimizingCompileDispatcher::IsQueuedForOSR(Handle<JSFunction> function,
+                                                 BailoutId osr_ast_id) {
+  for (int i = 0; i < osr_buffer_capacity_; i++) {
+    OptimizedCompileJob* current = osr_buffer_[i];
+    if (current != NULL &&
+        current->info()->HasSameOsrEntry(function, osr_ast_id)) {
+      return !current->IsWaitingForInstall();
+    }
+  }
+  return false;
+}
+
+
+bool OptimizingCompileDispatcher::IsQueuedForOSR(JSFunction* function) {
+  for (int i = 0; i < osr_buffer_capacity_; i++) {
+    OptimizedCompileJob* current = osr_buffer_[i];
+    if (current != NULL && *current->info()->closure() == function) {
+      return !current->IsWaitingForInstall();
+    }
+  }
+  return false;
+}
+
+
+void OptimizingCompileDispatcher::AddToOsrBuffer(OptimizedCompileJob* job) {
+  // Find the next slot that is empty or has a stale job.
+  OptimizedCompileJob* stale = NULL;
+  while (true) {
+    stale = osr_buffer_[osr_buffer_cursor_];
+    if (stale == NULL || stale->IsWaitingForInstall()) break;
+    osr_buffer_cursor_ = (osr_buffer_cursor_ + 1) % osr_buffer_capacity_;
+  }
+
+  // Add to found slot and dispose the evicted job.
+  if (stale != NULL) {
+    DCHECK(stale->IsWaitingForInstall());
+    CompilationInfo* info = stale->info();
+    if (FLAG_trace_osr) {
+      PrintF("[COSR - Discarded ");
+      info->closure()->PrintName();
+      PrintF(", AST id %d]\n", info->osr_ast_id().ToInt());
+    }
+    DisposeOptimizedCompileJob(stale, false);
+  }
+  osr_buffer_[osr_buffer_cursor_] = job;
+  osr_buffer_cursor_ = (osr_buffer_cursor_ + 1) % osr_buffer_capacity_;
+}
+}  // namespace internal
+}  // namespace v8