Use idle time to make progress on scheduled compilation jobs

src/compiler-dispatcher/compiler-dispatcher.h

 // Copyright 2016 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_COMPILER_DISPATCHER_COMPILER_DISPATCHER_H_
 #define V8_COMPILER_DISPATCHER_COMPILER_DISPATCHER_H_
 
 #include <map>
 #include <memory>
 #include <utility>
 
 #include "src/base/macros.h"
 #include "src/globals.h"
+#include "testing/gtest/include/gtest/gtest_prod.h"
 
 namespace v8 {
+
+class Platform;
+
 namespace internal {
 
 class CompilerDispatcherJob;
 class CompilerDispatcherTracer;
 class Isolate;
 class SharedFunctionInfo;
 
 template <typename T>
 class Handle;
 
+// The CompilerDispatcher uses a combination of idle tasks and background tasks
+// to parse and compile lazily parsed functions.
 class V8_EXPORT_PRIVATE CompilerDispatcher {
  public:
   enum class BlockingBehavior { kBlock, kDontBlock };
 
-  CompilerDispatcher(Isolate* isolate, size_t max_stack_size);
+  CompilerDispatcher(Isolate* isolate, Platform* platform,
+                     size_t max_stack_size);
   ~CompilerDispatcher();
 
   // Returns true if a job was enqueued.
   bool Enqueue(Handle<SharedFunctionInfo> function);
 
   // Returns true if there is a pending job for the given function.
   bool IsEnqueued(Handle<SharedFunctionInfo> function) const;
 
   // Blocks until the given function is compiled (and does so as fast as
   // possible). Returns true if the compile job was succesful.
   bool FinishNow(Handle<SharedFunctionInfo> function);
 
   // Aborts a given job. Blocks if requested.
   void Abort(Handle<SharedFunctionInfo> function, BlockingBehavior blocking);
 
   // Aborts all jobs. Blocks if requested.
   void AbortAll(BlockingBehavior blocking);
 
  private:
+  FRIEND_TEST(CompilerDispatcherTest, IdleTaskSmallIdleTime);
+
   typedef std::multimap<std::pair<int, int>,
                         std::unique_ptr<CompilerDispatcherJob>>
       JobMap;
+  class IdleTask;
+
   JobMap::const_iterator GetJobFor(Handle<SharedFunctionInfo> shared) const;
+  void ScheduleIdleTaskIfNeeded();
+  void DoIdleWork(double deadline_in_seconds);
 
   Isolate* isolate_;
+  Platform* platform_;
   size_t max_stack_size_;
   std::unique_ptr<CompilerDispatcherTracer> tracer_;
 
+  bool idle_task_scheduled_;
+
   // Mapping from (script id, function literal id) to job. We use a multimap,
   // as script id is not necessarily unique.
   JobMap jobs_;
 
   DISALLOW_COPY_AND_ASSIGN(CompilerDispatcher);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_DISPATCHER_COMPILER_DISPATCHER_H_