--- /dev/null	2019-02-14 11:31:37.500399000 +0100
+++ new/src/hotspot/share/gc/shared/scavengableNMethods.hpp	2019-03-11 22:56:30.774839703 +0100
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * 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_SHARED_SCAVENGABLENMETHODS_HPP
+#define SHARE_GC_SHARED_SCAVENGABLENMETHODS_HPP
+
+#include "memory/allocation.hpp"
+#include "utilities/macros.hpp"
+
+class BoolObjectClosure;
+class CodeBlobClosure;
+class CodeBlobToOopClosure;
+class nmethod;
+
+class ScavengableNMethods : public AllStatic {
+  friend class VMStructs;
+
+  static nmethod*           _head;
+  static BoolObjectClosure* _is_scavengable;
+
+public:
+  static void initialize(BoolObjectClosure* is_scavengable);
+
+  static void register_nmethod(nmethod* nm);
+  static void unregister_nmethod(nmethod* nm);
+  static void verify_nmethod(nmethod* nm);
+  static void flush_nmethod(nmethod* nm);
+
+  static void prune_nmethods();
+
+  // Apply f to every live code blob in scavengable nmethods. Prune nmethods
+  // from the list of scavengable nmethods if f->fix_relocations() and a nmethod
+  // no longer has scavengable oops.  If f->fix_relocations(), then f must copy
+  // objects to their new location immediately to avoid fixing nmethods on the
+  // basis of the old object locations.
+  static void scavengable_nmethods_do(CodeBlobToOopClosure* f);
+
+  static void asserted_non_scavengable_nmethods_do(CodeBlobClosure* f = NULL) PRODUCT_RETURN;
+
+private:
+  static void unlist_nmethod(nmethod* nm, nmethod* prev);
+
+  static bool has_scavengable_oops(nmethod* nm);
+
+  static void mark_on_list_nmethods() PRODUCT_RETURN;
+  static void verify_unlisted_nmethods(CodeBlobClosure* f_or_null) PRODUCT_RETURN;
+};
+
+#endif // SHARE_GC_SHARED_SCAVENGABLENMETHODS_HPP