--- /dev/null	2017-08-28 14:09:49.000000000 -0700
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot/src/org/graalvm/compiler/hotspot/meta/HotSpotUnsafeSubstitutions.java	2017-08-28 14:09:49.000000000 -0700
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2017, 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.
+ */
+package org.graalvm.compiler.hotspot.meta;
+
+import static org.graalvm.compiler.serviceprovider.JDK9Method.Java8OrEarlier;
+
+import org.graalvm.compiler.api.replacements.ClassSubstitution;
+import org.graalvm.compiler.api.replacements.MethodSubstitution;
+import org.graalvm.compiler.hotspot.HotSpotBackend;
+import org.graalvm.compiler.hotspot.nodes.ComputeObjectAddressNode;
+import org.graalvm.compiler.word.Word;
+import org.graalvm.word.WordFactory;
+
+@ClassSubstitution(className = {"jdk.internal.misc.Unsafe", "sun.misc.Unsafe"})
+public class HotSpotUnsafeSubstitutions {
+
+    public static final String copyMemoryName = Java8OrEarlier ? "copyMemory" : "copyMemory0";
+
+    @SuppressWarnings("unused")
+    @MethodSubstitution(isStatic = false)
+    static void copyMemory(Object receiver, Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes) {
+        Word srcAddr = WordFactory.unsigned(ComputeObjectAddressNode.get(srcBase, srcOffset));
+        Word dstAddr = WordFactory.unsigned(ComputeObjectAddressNode.get(destBase, destOffset));
+        Word size = Word.signed(bytes);
+        HotSpotBackend.unsafeArraycopy(srcAddr, dstAddr, size);
+    }
+}