--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotRuntime.java	Wed Jun 12 16:04:43 2013 +0200
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotRuntime.java	Wed Jun 12 17:24:20 2013 +0200
@@ -1076,6 +1076,9 @@
         if (AOTCompilation.getValue()) {
             // lowering introduces class constants, therefore it must be after lowering
             ret.getHighTier().addPhase(new LoadJavaMirrorWithKlassPhase());
+            if (VerifyPhases.getValue()) {
+                ret.getHighTier().addPhase(new AheadOfTimeVerifcationPhase());
+            }
         }
 
         ret.getMidTier().addPhase(new WriteBarrierAdditionPhase());

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/phases/AheadOfTimeVerifcationPhase.java	Wed Jun 12 17:24:20 2013 +0200
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2013, 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 com.oracle.graal.hotspot.phases;
+
+import com.oracle.graal.api.meta.*;
+import com.oracle.graal.nodes.*;
+import com.oracle.graal.phases.*;
+
+public class AheadOfTimeVerifcationPhase extends VerifyPhase {
+
+    @Override
+    protected boolean verify(StructuredGraph graph) {
+        for (ConstantNode node : graph.getNodes().filter(ConstantNode.class)) {
+            assert !isOop(node) || isNullReference(node) || isString(node) : "embedded oop: " + node;
+        }
+        return true;
+    }
+
+    private static boolean isOop(ConstantNode node) {
+        return node.kind() == Kind.Object;
+    }
+
+    private static boolean isNullReference(ConstantNode node) {
+        return isOop(node) && node.asConstant().asObject() == null;
+    }
+
+    private static boolean isString(ConstantNode node) {
+        return isOop(node) && node.asConstant().asObject() instanceof String;
+    }
+}