Implement missing functionality for job based recompilation

src/optimizing-compiler-thread.cc

 // 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-compiler-thread.h"
 
 #include "src/v8.h"
 
 #include "src/base/atomicops.h"
 #include "src/full-codegen.h"
 #include "src/hydrogen.h"
 #include "src/isolate.h"
 #include "src/v8threads.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 OptimizingCompilerThread::CompileTask : public v8::Task {
  public:
-  CompileTask(Isolate* isolate, OptimizedCompileJob* job)
-      : isolate_(isolate), job_(job) {}
+  explicit CompileTask(Isolate* isolate) : isolate_(isolate) {}
 
   virtual ~CompileTask() {}
 
  private:
   // v8::Task overrides.
   void Run() OVERRIDE {
     DisallowHeapAllocation no_allocation;
     DisallowHandleAllocation no_handles;
     DisallowHandleDereference no_deref;
 
-    // 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);
+    TimerEventScope<TimerEventRecompileConcurrent> timer(isolate_);
 
-    // 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.
+    OptimizingCompilerThread* thread = isolate_->optimizing_compiler_thread();
+
+    if (thread->recompilation_delay_ != 0) {
+      base::OS::Sleep(thread->recompilation_delay_);
+    }
+
+    StopFlag flag;
+    OptimizedCompileJob* job = thread->NextInput(&flag);
+
+    if (flag == CONTINUE) {
+      thread->CompileNext(job);
+    } else {
+      AllowHandleDereference allow_handle_dereference;
+      if (!job->info()->is_osr()) {
+        DisposeOptimizedCompileJob(job, true);
+      }
+    }
+    bool signal = false;
     {
-      base::LockGuard<base::Mutex> lock_guard(
-          &isolate_->optimizing_compiler_thread()->output_queue_mutex_);
-      isolate_->optimizing_compiler_thread()->output_queue_.Enqueue(job_);
+      base::LockGuard<base::RecursiveMutex> lock(&thread->task_count_mutex_);
+      if (--thread->task_count_ == 0) {
+        if (static_cast<StopFlag>(base::Acquire_Load(&thread->stop_thread_)) ==
+            FLUSH) {
+          base::Release_Store(&thread->stop_thread_,
+                              static_cast<base::AtomicWord>(CONTINUE));
+          signal = true;
+        }
+      }
     }
-    isolate_->stack_guard()->RequestInstallCode();
-    {
-      base::LockGuard<base::Mutex> lock_guard(
-          &isolate_->optimizing_compiler_thread()->input_queue_mutex_);
-      isolate_->optimizing_compiler_thread()->input_queue_length_--;
-    }
-    isolate_->optimizing_compiler_thread()->input_queue_semaphore_.Signal();
+    if (signal) thread->stop_semaphore_.Signal();
   }
 
   Isolate* isolate_;
-  OptimizedCompileJob* job_;
 
   DISALLOW_COPY_AND_ASSIGN(CompileTask);
 };
 
 
 OptimizingCompilerThread::~OptimizingCompilerThread() {
   DCHECK_EQ(0, input_queue_length_);
   DeleteArray(input_queue_);
   if (FLAG_concurrent_osr) {
 #ifdef DEBUG
@@ skipping 20 matching lines @@
     return;
   }
 
   base::ElapsedTimer total_timer;
   if (tracing_enabled_) total_timer.Start();
 
   while (true) {
     input_queue_semaphore_.Wait();
     TimerEventScope<TimerEventRecompileConcurrent> timer(isolate_);
 
-    if (FLAG_concurrent_recompilation_delay != 0) {
-      base::OS::Sleep(FLAG_concurrent_recompilation_delay);
+    if (recompilation_delay_ != 0) {
+      base::OS::Sleep(recompilation_delay_);
     }
 
     switch (static_cast<StopFlag>(base::Acquire_Load(&stop_thread_))) {
       case CONTINUE:
         break;
       case STOP:
         if (tracing_enabled_) {
           time_spent_total_ = total_timer.Elapsed();
         }
         stop_semaphore_.Signal();
         return;
       case FLUSH:
         // The main thread is blocked, waiting for the stop semaphore.
         { AllowHandleDereference allow_handle_dereference;
           FlushInputQueue(true);
         }
         base::Release_Store(&stop_thread_,
                             static_cast<base::AtomicWord>(CONTINUE));
         stop_semaphore_.Signal();
         // Return to start of consumer loop.
         continue;
     }
 
     base::ElapsedTimer compiling_timer;
     if (tracing_enabled_) compiling_timer.Start();
 
-    CompileNext();
+    CompileNext(NextInput());
 
     if (tracing_enabled_) {
       time_spent_compiling_ += compiling_timer.Elapsed();
     }
   }
 }
 
 
-OptimizedCompileJob* OptimizingCompilerThread::NextInput() {
+OptimizedCompileJob* OptimizingCompilerThread::NextInput(StopFlag* flag) {
   base::LockGuard<base::Mutex> access_input_queue_(&input_queue_mutex_);
-  DCHECK(!job_based_recompilation_);
-  if (input_queue_length_ == 0) return NULL;
+  if (input_queue_length_ == 0) {
+    if (flag) {
+      UNREACHABLE();
+      *flag = CONTINUE;
+    }
+    return NULL;
+  }
   OptimizedCompileJob* job = input_queue_[InputQueueIndex(0)];
   DCHECK_NE(NULL, job);
   input_queue_shift_ = InputQueueIndex(1);
   input_queue_length_--;
+  if (flag) {
+    *flag = static_cast<StopFlag>(base::Acquire_Load(&stop_thread_));
+  }
   return job;
 }
 
 
-void OptimizingCompilerThread::CompileNext() {
-  OptimizedCompileJob* job = NextInput();
+void OptimizingCompilerThread::CompileNext(OptimizedCompileJob* job) {
   DCHECK_NE(NULL, job);
 
   // 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.
+  if (job_based_recompilation_) output_queue_mutex_.Lock();
   output_queue_.Enqueue(job);
+  if (job_based_recompilation_) output_queue_mutex_.Unlock();
   isolate_->stack_guard()->RequestInstallCode();
 }
 
 
-static 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;
-}
-
-
 void OptimizingCompilerThread::FlushInputQueue(bool restore_function_code) {
-  DCHECK(!job_based_recompilation_);
   OptimizedCompileJob* job;
   while ((job = NextInput())) {
+    DCHECK(!job_based_recompilation_);
     // This should not block, since we have one signal on the input queue
     // semaphore corresponding to each element in the input queue.
     input_queue_semaphore_.Wait();
     // OSR jobs are dealt with separately.
     if (!job->info()->is_osr()) {
       DisposeOptimizedCompileJob(job, restore_function_code);
     }
   }
 }
 
 
 void OptimizingCompilerThread::FlushOutputQueue(bool restore_function_code) {
+  base::LockGuard<base::Mutex> access_output_queue_(&output_queue_mutex_);
   OptimizedCompileJob* job;
   while (output_queue_.Dequeue(&job)) {
     // OSR jobs are dealt with separately.
     if (!job->info()->is_osr()) {
       DisposeOptimizedCompileJob(job, restore_function_code);
     }
   }
 }
 
 
 void OptimizingCompilerThread::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 OptimizingCompilerThread::Flush() {
   DCHECK(!IsOptimizerThread());
-  base::Release_Store(&stop_thread_, static_cast<base::AtomicWord>(FLUSH));
-  if (FLAG_block_concurrent_recompilation) Unblock();
-  if (!job_based_recompilation_) {
-    input_queue_semaphore_.Signal();
-    stop_semaphore_.Wait();
+  bool block = true;
+  if (job_based_recompilation_) {
+    base::LockGuard<base::RecursiveMutex> lock(&task_count_mutex_);
+    block = task_count_ > 0 || blocked_jobs_ > 0;
+    if (block) {
+      base::Release_Store(&stop_thread_, static_cast<base::AtomicWord>(FLUSH));
+    }
+    if (FLAG_block_concurrent_recompilation) Unblock();
+  } else {
+    base::Release_Store(&stop_thread_, static_cast<base::AtomicWord>(FLUSH));
+    if (FLAG_block_concurrent_recompilation) Unblock();
   }
+  if (!job_based_recompilation_) input_queue_semaphore_.Signal();
+  if (block) stop_semaphore_.Wait();
   FlushOutputQueue(true);
   if (FLAG_concurrent_osr) FlushOsrBuffer(true);
   if (tracing_enabled_) {
     PrintF("  ** Flushed concurrent recompilation queues.\n");
   }
 }
 
 
 void OptimizingCompilerThread::Stop() {
   DCHECK(!IsOptimizerThread());
-  base::Release_Store(&stop_thread_, static_cast<base::AtomicWord>(STOP));
-  if (FLAG_block_concurrent_recompilation) Unblock();
-  if (!job_based_recompilation_) {
-    input_queue_semaphore_.Signal();
-    stop_semaphore_.Wait();
+  bool block = true;
+  if (job_based_recompilation_) {
+    base::LockGuard<base::RecursiveMutex> lock(&task_count_mutex_);
+    block = task_count_ > 0 || blocked_jobs_ > 0;
+    if (block) {
+      base::Release_Store(&stop_thread_, static_cast<base::AtomicWord>(FLUSH));
+    }
+    if (FLAG_block_concurrent_recompilation) Unblock();
+  } else {
+    base::Release_Store(&stop_thread_, static_cast<base::AtomicWord>(STOP));
+    if (FLAG_block_concurrent_recompilation) Unblock();
   }
+  if (!job_based_recompilation_) input_queue_semaphore_.Signal();
+  if (block) stop_semaphore_.Wait();
 
-  if (job_based_recompilation_) {
-    while (true) {
-      {
-        base::LockGuard<base::Mutex> access_input_queue(&input_queue_mutex_);
-        if (!input_queue_length_) break;
-      }
-      input_queue_semaphore_.Wait();
-    }
-  } else if (FLAG_concurrent_recompilation_delay != 0) {
+  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();
+    while (input_queue_length_ > 0) CompileNext(NextInput());
     InstallOptimizedFunctions();
   } else {
     FlushInputQueue(false);
     FlushOutputQueue(false);
   }
 
   if (FLAG_concurrent_osr) FlushOsrBuffer(false);
 
   if (tracing_enabled_) {
     double percentage = time_spent_compiling_.PercentOf(time_spent_total_);
+    if (job_based_recompilation_) percentage = 100.0;
     PrintF("  ** Compiler thread did %.2f%% useful work\n", percentage);
   }
 
   if ((FLAG_trace_osr || tracing_enabled_) && FLAG_concurrent_osr) {
     PrintF("[COSR hit rate %d / %d]\n", osr_hits_, osr_attempts_);
   }
 
   Join();
 }
 
@@ skipping 50 matching lines @@
     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 (job_based_recompilation_) {
+  if (FLAG_block_concurrent_recompilation) {
+    blocked_jobs_++;
+  } else if (job_based_recompilation_) {
+    base::LockGuard<base::RecursiveMutex> lock(&task_count_mutex_);
+    ++task_count_;
     V8::GetCurrentPlatform()->CallOnBackgroundThread(
-        new CompileTask(isolate_, job), v8::Platform::kShortRunningTask);
-  } else if (FLAG_block_concurrent_recompilation) {
-    blocked_jobs_++;
+        new CompileTask(isolate_), v8::Platform::kShortRunningTask);
   } else {
     input_queue_semaphore_.Signal();
   }
 }
 
 
 void OptimizingCompilerThread::Unblock() {
   DCHECK(!IsOptimizerThread());
-  if (job_based_recompilation_) {
-    return;
+  {
+    base::LockGuard<base::RecursiveMutex> lock(&task_count_mutex_);
+    task_count_ += blocked_jobs_;
   }
   while (blocked_jobs_ > 0) {
-    input_queue_semaphore_.Signal();
+    if (job_based_recompilation_) {
+      V8::GetCurrentPlatform()->CallOnBackgroundThread(
+          new CompileTask(isolate_), v8::Platform::kShortRunningTask);
+    } else {
+      input_queue_semaphore_.Signal();
+    }
     blocked_jobs_--;
   }
 }
 
 
 OptimizedCompileJob* OptimizingCompilerThread::FindReadyOSRCandidate(
     Handle<JSFunction> function, BailoutId osr_ast_id) {
   DCHECK(!IsOptimizerThread());
   for (int i = 0; i < osr_buffer_capacity_; i++) {
     OptimizedCompileJob* current = osr_buffer_[i];
@@ skipping 69 matching lines @@
 
 
 bool OptimizingCompilerThread::IsOptimizerThread() {
   base::LockGuard<base::Mutex> lock_guard(&thread_id_mutex_);
   return ThreadId::Current().ToInteger() == thread_id_;
 }
 #endif
 
 
 } }  // namespace v8::internal