Initial design for background compilation

runtime/vm/compiler.h

Index: runtime/vm/compiler.h
diff --git a/runtime/vm/compiler.h b/runtime/vm/compiler.h
index 9dc11b810541b2fa2ad60138e3752967a475021e..8eed617e3e37a574b8cf3655cc9334fb3266e249 100644
--- a/runtime/vm/compiler.h
+++ b/runtime/vm/compiler.h
@@ -8,6 +8,7 @@
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
 #include "vm/runtime_entry.h"
+#include "vm/thread_pool.h"
 
 namespace dart {
 
@@ -99,6 +100,35 @@ class Compiler : public AllStatic {
   static bool allow_recompilation_;
 };
 
+
+class CompileOptimizedTask : public ThreadPool::Task {
+ public:
+  explicit CompileOptimizedTask(Isolate* isolate);
+  ~CompileOptimizedTask();

[koda, 2015/10/01 22:27:02]

I believe this is the first task that defines a destructor. Couldn't you do all
cleanup in Stop, to avoid the split?

Also consider adding 'virtual', for clarity.

[srdjan, 2015/10/01 23:11:24]

Removes destructor, all cleanup in Stop.

+
+  virtual void Run();
+
+  void CompileOptimized(const Function& function);
+
+  void Add(const Function& f);
+  RawFunction* RemoveOrNull();
+
+  Monitor* monitor() const { return monitor_; }
+
+  static void Init(Isolate* isolate);

[koda, 2015/10/01 22:27:02]

What happens if multiple threads call 'Init'? Consider renaming EnsureInit and
use the isolate's mutex.

[srdjan, 2015/10/01 23:11:24]

Done. There is currently only one Dart code thread, but better safe!

+
+  static void Stop(CompileOptimizedTask* task);
+
+ private:
+  Isolate* isolate_;
+  bool running_;
+  bool* done_;
+  Monitor* monitor_;
+  Monitor* done_monitor_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(CompileOptimizedTask);
+};
+
 }  // namespace dart
 
 #endif  // VM_COMPILER_H_