diff -r 8b6cc0bb93d0 -r 9186be5c78ba src/hotspot/share/gc/shenandoah/shenandoahBarrierSetNMethod.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/shenandoah/shenandoahBarrierSetNMethod.cpp	Wed Nov 27 11:52:57 2019 -0500
@@ -0,0 +1,76 @@
+/*
+ * 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.
+ *
+ */
+
+#include "precompiled.hpp"
+
+#include "gc/shenandoah/shenandoahBarrierSetNMethod.hpp"
+#include "gc/shenandoah/shenandoahClosures.inline.hpp"
+#include "gc/shenandoah/shenandoahCodeRoots.hpp"
+#include "gc/shenandoah/shenandoahHeap.inline.hpp"
+#include "gc/shenandoah/shenandoahLock.hpp"
+#include "gc/shenandoah/shenandoahNMethod.inline.hpp"
+#include "gc/shenandoah/shenandoahThreadLocalData.hpp"
+#include "memory/iterator.hpp"
+#include "memory/resourceArea.hpp"
+
+bool ShenandoahBarrierSetNMethod::nmethod_entry_barrier(nmethod* nm) {
+  ShenandoahReentrantLock* lock = ShenandoahNMethod::lock_for_nmethod(nm);
+  assert(lock != NULL, "Must be");
+  ShenandoahReentrantLocker locker(lock);
+
+  if (!is_armed(nm)) {
+    // Some other thread got here first and healed the oops
+    // and disarmed the nmethod.
+    return true;
+  }
+
+  if (nm->is_unloading()) {
+    // We don't need to take the lock when unlinking nmethods from
+    // the Method, because it is only concurrently unlinked by
+    // the entry barrier, which acquires the per nmethod lock.
+    nm->unlink_from_method();
+
+    // We can end up calling nmethods that are unloading
+    // since we clear compiled ICs lazily. Returning false
+    // will re-resovle the call and update the compiled IC.
+    return false;
+  }
+
+  // Heal oops and disarm
+  ShenandoahEvacOOMScope scope;
+  ShenandoahNMethod::heal_nmethod(nm);
+  ShenandoahNMethod::disarm_nmethod(nm);
+  return true;
+}
+
+int ShenandoahBarrierSetNMethod::disarmed_value() const {
+  return ShenandoahCodeRoots::disarmed_value();
+}
+
+ByteSize ShenandoahBarrierSetNMethod::thread_disarmed_offset() const {
+  return ShenandoahThreadLocalData::disarmed_value_offset();
+}
+
+int* ShenandoahBarrierSetNMethod::disarmed_value_address() const {
+  return ShenandoahCodeRoots::disarmed_value_address();
+}