Old-gen marking on separate thread

runtime/vm/thread.h

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_THREAD_H_
 #define VM_THREAD_H_
 
 #include "vm/globals.h"
 #include "vm/os_thread.h"
 #include "vm/store_buffer.h"
@@ skipping 65 matching lines @@
 
   // Makes the current thread enter 'isolate'.
   static void EnterIsolate(Isolate* isolate);
   // Makes the current thread exit its isolate.
   static void ExitIsolate();
 
   // A VM thread other than the main mutator thread can enter an isolate as a
   // "helper" to gain limited concurrent access to the isolate. One example is
   // SweeperTask (which uses the class table, which is copy-on-write).
   // TODO(koda): Properly synchronize heap access to expand allowed operations.
-  static void EnterIsolateAsHelper(Isolate* isolate);
-  static void ExitIsolateAsHelper();
+  static void EnterIsolateAsHelper(Isolate* isolate,
+                                   bool bypass_safepoint = false);
+  static void ExitIsolateAsHelper(bool bypass_safepoint = false);
 
   // Called when the current thread transitions from mutator to collector.
   // Empties the store buffer block into the isolate.
   // TODO(koda): Always run GC in separate thread.
   static void PrepareForGC();
 
 #if defined(TARGET_OS_WINDOWS)
   // Clears the state of the current thread and frees the allocation.
   static void CleanUp();
 #endif
@@ skipping 182 matching lines @@
   void set_zone(Zone* zone) {
     state_.zone = zone;
   }
 
   void set_top_exit_frame_info(uword top_exit_frame_info) {
     state_.top_exit_frame_info = top_exit_frame_info;
   }
 
   static void SetCurrent(Thread* current);
 
-  void Schedule(Isolate* isolate);
-  void Unschedule();
+  void Schedule(Isolate* isolate, bool bypass_safepoint = false);
+  void Unschedule(bool bypass_safepoint = false);
 
   friend class ApiZone;
   friend class Isolate;
   friend class StackZone;
   friend class ThreadRegistry;
   DISALLOW_COPY_AND_ASSIGN(Thread);
 };
 
 }  // namespace dart
 
 #endif  // VM_THREAD_H_