--- a/jvmci/jdk.vm.ci.code/src/jdk/vm/ci/code/site/DataPatch.java	Tue Nov 22 11:34:29 2016 +0100
+++ b/jvmci/jdk.vm.ci.code/src/jdk/vm/ci/code/site/DataPatch.java	Tue Nov 22 11:40:31 2016 +0100
@@ -34,15 +34,27 @@
 public final class DataPatch extends Site {
 
     public Reference reference;
+    public Object note;
 
     public DataPatch(int pcOffset, Reference reference) {
         super(pcOffset);
         this.reference = reference;
+        this.note = null;
+    }
+
+    public DataPatch(int pcOffset, Reference reference, Object note) {
+        super(pcOffset);
+        this.reference = reference;
+        this.note = note;
     }
 
     @Override
     public String toString() {
-        return String.format("%d[<data patch referring to %s>]", pcOffset, reference.toString());
+        if (note != null) {
+            return String.format("%d[<data patch referring to %s>, note: %s]", pcOffset, reference.toString(), note.toString());
+        } else {
+            return String.format("%d[<data patch referring to %s>]", pcOffset, reference.toString());
+        }
     }
 
     @Override
@@ -52,7 +64,7 @@
         }
         if (obj instanceof DataPatch) {
             DataPatch that = (DataPatch) obj;
-            if (this.pcOffset == that.pcOffset && Objects.equals(this.reference, that.reference)) {
+            if (this.pcOffset == that.pcOffset && Objects.equals(this.reference, that.reference) && Objects.equals(this.note, that.note)) {
                 return true;
             }
         }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jvmci/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotSentinelConstant.java	Tue Nov 22 11:40:31 2016 +0100
@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2014, 2016, 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 jdk.vm.ci.meta.JavaConstant;
+import jdk.vm.ci.meta.JavaKind;
+import jdk.vm.ci.meta.ValueKind;
+import jdk.vm.ci.meta.VMConstant;
+import jdk.vm.ci.meta.Value;
+
+public final class HotSpotSentinelConstant extends Value implements JavaConstant, VMConstant {
+
+    private final JavaKind javaKind;
+
+    public HotSpotSentinelConstant(ValueKind<?> valueKind, JavaKind javaKind) {
+        super(valueKind);
+        this.javaKind = javaKind;
+    }
+
+    public JavaKind getJavaKind() {
+        return javaKind;
+    }
+
+    @Override
+    public boolean isNull() {
+        return true;
+    }
+
+    @Override
+    public boolean isDefaultForKind() {
+        return true;
+    }
+
+    @Override
+    public Object asBoxedPrimitive() {
+        throw new IllegalArgumentException();
+    }
+
+    @Override
+    public int asInt() {
+        throw new IllegalArgumentException();
+    }
+
+    @Override
+    public boolean asBoolean() {
+        throw new IllegalArgumentException();
+    }
+
+    @Override
+    public long asLong() {
+        throw new IllegalArgumentException();
+    }
+
+    @Override
+    public float asFloat() {
+        throw new IllegalArgumentException();
+    }
+
+    @Override
+    public double asDouble() {
+        throw new IllegalArgumentException();
+    }
+
+    @Override
+    public String toString() {
+        return JavaConstant.toString(this);
+    }
+
+    @Override
+    public String toValueString() {
+        return "sentinel";
+    }
+
+    @Override
+    public int hashCode() {
+        return 13;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        return o instanceof HotSpotSentinelConstant;
+    }
+}