--- /dev/null	2015-10-08 07:25:19.000000000 -1000
+++ new/src/jdk.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotNmethod.java	2015-10-08 07:25:19.000000000 -1000
@@ -0,0 +1,116 @@
+/*
+ * Copyright (c) 2011, 2015, 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 jdk.vm.ci.hotspot;
+
+import static jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.*;
+
+import jdk.vm.ci.code.*;
+import jdk.vm.ci.meta.*;
+
+/**
+ * Implementation of {@link InstalledCode} for code installed as an nmethod. The nmethod stores a
+ * weak reference to an instance of this class. This is necessary to keep the nmethod from being
+ * unloaded while the associated {@link HotSpotNmethod} instance is alive.
+ * <p>
+ * Note that there is no (current) way for the reference from an nmethod to a {@link HotSpotNmethod}
+ * instance to be anything but weak. This is due to the fact that HotSpot does not treat nmethods as
+ * strong GC roots.
+ */
+public class HotSpotNmethod extends HotSpotInstalledCode {
+
+    /**
+     * This (indirect) Method* reference is safe since class redefinition preserves all methods
+     * associated with nmethods in the code cache.
+     */
+    private final HotSpotResolvedJavaMethod method;
+
+    private final boolean isDefault;
+    private final boolean isExternal;
+
+    public HotSpotNmethod(HotSpotResolvedJavaMethod method, String name, boolean isDefault) {
+        this(method, name, isDefault, false);
+    }
+
+    public HotSpotNmethod(HotSpotResolvedJavaMethod method, String name, boolean isDefault, boolean isExternal) {
+        super(name);
+        this.method = method;
+        this.isDefault = isDefault;
+        this.isExternal = isExternal;
+    }
+
+    public boolean isDefault() {
+        return isDefault;
+    }
+
+    public boolean isExternal() {
+        return isExternal;
+    }
+
+    public ResolvedJavaMethod getMethod() {
+        return method;
+    }
+
+    @Override
+    public void invalidate() {
+        runtime().getCompilerToVM().invalidateInstalledCode(this);
+    }
+
+    @Override
+    public String toString() {
+        return String.format("InstalledNmethod[method=%s, codeBlob=0x%x, isDefault=%b, name=%s]", method, getAddress(), isDefault, name);
+    }
+
+    protected boolean checkThreeObjectArgs() {
+        assert method.getSignature().getParameterCount(!method.isStatic()) == 3;
+        assert method.getSignature().getParameterKind(0) == JavaKind.Object;
+        assert method.getSignature().getParameterKind(1) == JavaKind.Object;
+        assert !method.isStatic() || method.getSignature().getParameterKind(2) == JavaKind.Object;
+        return true;
+    }
+
+    private boolean checkArgs(Object... args) {
+        JavaType[] sig = method.toParameterTypes();
+        assert args.length == sig.length : method.format("%H.%n(%p): expected ") + sig.length + " args, got " + args.length;
+        for (int i = 0; i < sig.length; i++) {
+            Object arg = args[i];
+            if (arg == null) {
+                assert sig[i].getJavaKind() == JavaKind.Object : method.format("%H.%n(%p): expected arg ") + i + " to be Object, not " + sig[i];
+            } else if (sig[i].getJavaKind() != JavaKind.Object) {
+                assert sig[i].getJavaKind().toBoxedJavaClass() == arg.getClass() : method.format("%H.%n(%p): expected arg ") + i + " to be " + sig[i] + ", not " + arg.getClass();
+            }
+        }
+        return true;
+    }
+
+    @Override
+    public Object executeVarargs(Object... args) throws InvalidInstalledCodeException {
+        assert checkArgs(args);
+        assert !isExternal();
+        return runtime().getCompilerToVM().executeInstalledCode(args, this);
+    }
+
+    @Override
+    public long getStart() {
+        return isValid() ? super.getStart() : 0;
+    }
+}