--- /dev/null	2017-01-22 10:16:57.869617664 -0800
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.phases/src/org/graalvm/compiler/phases/verify/VerifyVirtualizableUsage.java	2017-02-15 17:08:36.840807289 -0800
@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2015, 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 org.graalvm.compiler.phases.verify;
+
+import org.graalvm.compiler.core.common.type.ObjectStamp;
+import org.graalvm.compiler.core.common.type.Stamp;
+import org.graalvm.compiler.graph.Graph;
+import org.graalvm.compiler.graph.Node;
+import org.graalvm.compiler.graph.NodeInputList;
+import org.graalvm.compiler.nodes.ConstantNode;
+import org.graalvm.compiler.nodes.StructuredGraph;
+import org.graalvm.compiler.nodes.ValueNode;
+import org.graalvm.compiler.nodes.java.MethodCallTargetNode;
+import org.graalvm.compiler.nodes.spi.Virtualizable;
+import org.graalvm.compiler.phases.VerifyPhase;
+import org.graalvm.compiler.phases.tiers.PhaseContext;
+
+import jdk.vm.ci.meta.ResolvedJavaMethod;
+import jdk.vm.ci.meta.ResolvedJavaType;
+
+/**
+ *
+ * Verifies that node types implementing the {@link Virtualizable} interface use it correctly.
+ * Implementors of {@link Virtualizable#virtualize(org.graalvm.compiler.nodes.spi.VirtualizerTool)}
+ * must not apply effects on their {@link Graph graph} that cannot be easily undone.
+ */
+public class VerifyVirtualizableUsage extends VerifyPhase<PhaseContext> {
+    @Override
+    public boolean checkContract() {
+        return false;
+    }
+
+    @Override
+    protected boolean verify(StructuredGraph graph, PhaseContext context) {
+        final ResolvedJavaType graphType = context.getMetaAccess().lookupJavaType(Graph.class);
+        final ResolvedJavaType virtualizableType = context.getMetaAccess().lookupJavaType(Virtualizable.class);
+        final ResolvedJavaType constantNodeType = context.getMetaAccess().lookupJavaType(ConstantNode.class);
+        if (virtualizableType.isAssignableFrom(graph.method().getDeclaringClass()) && graph.method().getName().equals("virtualize")) {
+            for (MethodCallTargetNode t : graph.getNodes(MethodCallTargetNode.TYPE)) {
+                int bci = t.invoke().bci();
+                ResolvedJavaMethod callee = t.targetMethod();
+                String calleeName = callee.getName();
+                if (callee.getDeclaringClass().equals(graphType)) {
+                    if (calleeName.equals("add") || calleeName.equals("addWithoutUnique") || calleeName.equals("addOrUnique") || calleeName.equals("addWithoutUniqueWithInputs") ||
+                                    calleeName.equals("addOrUniqueWithInputs")) {
+                        verifyVirtualizableEffectArguments(constantNodeType, graph.method(), callee, bci, t.arguments(), 1);
+                    }
+                }
+            }
+        }
+        return true;
+    }
+
+    private static void verifyVirtualizableEffectArguments(ResolvedJavaType constantNodeType, ResolvedJavaMethod caller, ResolvedJavaMethod callee, int bciCaller,
+                    NodeInputList<? extends Node> arguments, int startIdx) {
+        /*
+         * Virtualizable.virtualize should never apply effects on the graph during the execution of
+         * the call as the handling of loops during pea might be speculative and does not hold. We
+         * should only allow nodes changing the graph that do no harm like constants.
+         */
+        int i = 0;
+        for (Node arg : arguments) {
+            if (i >= startIdx) {
+                Stamp argStamp = ((ValueNode) arg).stamp();
+                if (argStamp instanceof ObjectStamp) {
+                    ObjectStamp objectStamp = (ObjectStamp) argStamp;
+                    ResolvedJavaType argStampType = objectStamp.type();
+                    if (!(argStampType.equals(constantNodeType))) {
+                        StackTraceElement e = caller.asStackTraceElement(bciCaller);
+                        throw new VerificationError("%s:Parameter %d in call to %s (which has effects on the graph) is not a " +
+                                        "constant and thus not safe to apply during speculative virtualization.", e, i, callee.format("%H.%n(%p)"));
+                    }
+                }
+            }
+            i++;
+        }
+    }
+
+}