--- old/src/hotspot/share/gc/z/zRootsIterator.hpp	2019-12-09 22:12:12.906581453 +0100
+++ new/src/hotspot/share/gc/z/zRootsIterator.hpp	2019-12-09 22:12:12.702578232 +0100
@@ -31,10 +31,7 @@
 #include "runtime/thread.hpp"
 #include "utilities/globalDefinitions.hpp"
 
-class ZRootsIteratorClosure : public OopClosure {
-public:
-  virtual void do_thread(Thread* thread) {}
-};
+class ZRootsIteratorClosure;
 
 typedef OopStorage::ParState<true /* concurrent */, false /* is_const */> ZOopStorageIterator;
 
@@ -82,10 +79,18 @@
   void weak_oops_do(BoolObjectClosure* is_alive, ZRootsIteratorClosure* cl);
 };
 
+class ZRootsIteratorClosure : public OopClosure {
+public:
+  virtual void do_thread(Thread* thread) {}
+ 
+  virtual bool should_disarm_nmethods() const {
+    return false;
+  }
+};
+
 class ZRootsIterator {
 private:
   const bool _visit_jvmti_weak_export;
-  const bool _disarm_nmethods;
 
   void do_universe(ZRootsIteratorClosure* cl);
   void do_object_synchronizer(ZRootsIteratorClosure* cl);
@@ -106,7 +111,7 @@
   ZParallelOopsDo<ZRootsIterator, &ZRootsIterator::do_code_cache>        _code_cache;
 
 public:
-  ZRootsIterator(bool visit_jvmti_weak_export = false, bool disarm_nmethod = false);
+  ZRootsIterator(bool visit_jvmti_weak_export = false);
   ~ZRootsIterator();
 
   void oops_do(ZRootsIteratorClosure* cl);