--- /dev/null	2020-02-06 11:34:07.664987501 +0100
+++ new/src/hotspot/share/gc/shenandoah/shenandoahBarrierSetClone.inline.hpp	2020-02-06 19:19:31.984542574 +0100
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2013, 2019, Red Hat, Inc. All rights reserved.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSETCLONE_INLINE_HPP
+#define SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSETCLONE_INLINE_HPP
+
+#include "gc/shenandoah/shenandoahBarrierSet.inline.hpp"
+#include "gc/shenandoah/shenandoahCollectionSet.inline.hpp"
+#include "gc/shenandoah/shenandoahEvacOOMHandler.hpp"
+#include "gc/shenandoah/shenandoahHeap.inline.hpp"
+#include "memory/iterator.hpp"
+#include "oops/access.hpp"
+
+template <bool EVAC, bool ENQUEUE>
+class ShenandoahUpdateRefsForOopClosure: public BasicOopIterateClosure {
+private:
+  ShenandoahHeap* const _heap;
+  ShenandoahBarrierSet* const _bs;
+  const ShenandoahCollectionSet* const _cset;
+  Thread* const _thread;
+
+  template <class T>
+  inline void do_oop_work(T* p) {
+    T o = RawAccess<>::oop_load(p);
+    if (!CompressedOops::is_null(o)) {
+      oop obj = CompressedOops::decode_not_null(o);
+      if (_cset->is_in((HeapWord *)obj)) {
+        oop fwd = _bs->resolve_forwarded_not_null(obj);
+        if (EVAC && obj == fwd) {
+          fwd = _heap->evacuate_object(obj, _thread);
+        }
+        if (ENQUEUE) {
+          _bs->enqueue(fwd);
+        }
+        assert(obj != fwd || _heap->cancelled_gc(), "must be forwarded");
+        ShenandoahHeap::cas_oop(fwd, p, o);
+      }
+
+    }
+  }
+public:
+  ShenandoahUpdateRefsForOopClosure() :
+          _heap(ShenandoahHeap::heap()),
+          _bs(ShenandoahBarrierSet::barrier_set()),
+          _cset(_heap->collection_set()),
+          _thread(Thread::current()) {
+  }
+
+  virtual void do_oop(oop* p)       { do_oop_work(p); }
+  virtual void do_oop(narrowOop* p) { do_oop_work(p); }
+};
+
+void ShenandoahBarrierSet::clone_barrier(oop obj) {
+  assert(ShenandoahCloneBarrier, "only get here with clone barriers enabled");
+  assert(_heap->has_forwarded_objects(), "only when heap is unstable");
+
+  // This is called for cloning an object (see jvm.cpp) after the clone
+  // has been made. We are not interested in any 'previous value' because
+  // it would be NULL in any case. But we *are* interested in any oop*
+  // that potentially need to be updated.
+
+  shenandoah_assert_correct(NULL, obj);
+  if (_heap->is_evacuation_in_progress()) {
+    ShenandoahEvacOOMScope evac_scope;
+    ShenandoahUpdateRefsForOopClosure</* evac = */ true, /* enqueue */ false> cl;
+    obj->oop_iterate(&cl);
+  } else if (_heap->is_concurrent_traversal_in_progress()) {
+    ShenandoahEvacOOMScope evac_scope;
+    ShenandoahUpdateRefsForOopClosure</* evac = */ true, /* enqueue */ true> cl;
+    obj->oop_iterate(&cl);
+  } else {
+    ShenandoahUpdateRefsForOopClosure</* evac = */ false, /* enqueue */ false> cl;
+    obj->oop_iterate(&cl);
+  }
+}
+
+#endif // SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSETCLONE_INLINE_HPP