--- /dev/null	2020-01-17 11:46:19.065201212 +0100
+++ new/src/hotspot/share/gc/shenandoah/shenandoahRootVerifier.hpp	2020-01-17 17:10:33.992129163 +0100
@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 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_SHENANDOAHROOTVERIFIER_HPP
+#define SHARE_GC_SHENANDOAH_SHENANDOAHROOTVERIFIER_HPP
+
+#include "memory/allocation.hpp"
+#include "memory/iterator.hpp"
+
+class ShenandoahRootVerifier : public StackObj {
+public:
+  enum RootTypes {
+    SerialRoots         = 1 << 0,
+    ThreadRoots         = 1 << 1,
+    CodeRoots           = 1 << 2,
+    CLDGRoots           = 1 << 3,
+    WeakRoots           = 1 << 4,
+    StringDedupRoots    = 1 << 5,
+    JNIHandleRoots      = 1 << 6,
+    AllRoots            = (SerialRoots | ThreadRoots | CodeRoots | CLDGRoots | WeakRoots | StringDedupRoots | JNIHandleRoots)
+  };
+
+private:
+  RootTypes _types;
+
+public:
+  ShenandoahRootVerifier();
+
+  void excludes(RootTypes types);
+  void oops_do(OopClosure* cl);
+
+  // Used to seed ShenandoahVerifier, do not honor root type filter
+  void roots_do(OopClosure* cl);
+  void strong_roots_do(OopClosure* cl);
+private:
+  bool verify(RootTypes type) const;
+};
+
+#endif // SHARE_GC_SHENANDOAH_SHENANDOAHROOTVERIFIER_HPP