[platform] Implement a worker pool

src/libplatform/task-queue.cc

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-#ifndef V8_HYDROGEN_INFER_TYPES_H_
-#define V8_HYDROGEN_INFER_TYPES_H_
+#include "task-queue.h"
 
-#include "hydrogen.h"
+// TODO(jochen): We should have our own version of checks.h.
+#include "../checks.h"
 
 namespace v8 {
 namespace internal {
 
-
-class HInferTypesPhase : public HPhase {
- public:
-  explicit HInferTypesPhase(HGraph* graph)
-      : HPhase("H_Inferring types", graph), worklist_(8, zone()),
-        in_worklist_(graph->GetMaximumValueID(), zone()) { }
-
-  void Run() {
-    InferTypes(0, graph()->blocks()->length() - 1);
-  }
-
- private:
-  void InferTypes(int from_inclusive, int to_inclusive);
-
-  ZoneList<HValue*> worklist_;
-  BitVector in_worklist_;
-
-  DISALLOW_COPY_AND_ASSIGN(HInferTypesPhase);
-};
+TaskQueue::TaskQueue() : process_queue_semaphore_(0), terminated_(false) {}
 
 
+TaskQueue::~TaskQueue() {
+  LockGuard<Mutex> guard(&lock_);
+  ASSERT(terminated_);
+  ASSERT(task_queue_.empty());
+}
+
+
+void TaskQueue::Append(Task* task) {
+  LockGuard<Mutex> guard(&lock_);
+  ASSERT(!terminated_);
+  task_queue_.push(task);
+  process_queue_semaphore_.Signal();
+}
+
+
+Task* TaskQueue::GetNext() {
+  for (;;) {
+    {
+      LockGuard<Mutex> guard(&lock_);
+      if (!task_queue_.empty()) {
+        Task* result = task_queue_.front();
+        task_queue_.pop();
+        return result;
+      }
+      if (terminated_) {
+        process_queue_semaphore_.Signal();
+        return NULL;
+      }
+    }
+    process_queue_semaphore_.Wait();
+  }
+}
+
+
+void TaskQueue::Terminate() {
+  LockGuard<Mutex> guard(&lock_);
+  ASSERT(!terminated_);
+  terminated_ = true;
+  process_queue_semaphore_.Signal();
+}
+
 } }  // namespace v8::internal
-
-#endif  // V8_HYDROGEN_INFER_TYPES_H_