--- old/src/hotspot/share/gc/g1/g1CollectedHeap.hpp	2020-04-25 20:53:29.343347020 +0800
+++ new/src/hotspot/share/gc/g1/g1CollectedHeap.hpp	2020-04-25 20:53:29.179347521 +0800
@@ -550,7 +550,7 @@
 
   // Runs the given AbstractGangTask with the current active workers, returning the
   // total time taken.
-  Tickspan run_task(AbstractGangTask* task);
+  virtual Tickspan run_task(AbstractGangTask* task);
 
   G1Allocator* allocator() {
     return _allocator;
@@ -1167,9 +1167,13 @@
 
   // Iteration functions.
 
+  void object_iterate_parallel(ObjectClosure* cl, uint worker_id, HeapRegionClaimer* claimer);
+
   // Iterate over all objects, calling "cl.do_object" on each.
   virtual void object_iterate(ObjectClosure* cl);
 
+  virtual ParallelObjectIterator* parallel_object_iterator(uint thread_num);
+
   // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
   virtual void keep_alive(oop obj);