--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.max.graal.compiler/src/com/sun/c1x/ir/AccessMonitor.java	Wed Jun 08 08:42:25 2011 +0200
@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2009, 2011, 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.sun.c1x.ir;
+
+import com.oracle.graal.graph.*;
+import com.sun.cri.ci.*;
+
+/**
+ * The {@code AccessMonitor} instruction is the base class of both monitor acquisition and release.
+ */
+public abstract class AccessMonitor extends StateSplit {
+
+    private static final int INPUT_COUNT = 2;
+    private static final int INPUT_OBJECT = 0;
+    private static final int INPUT_LOCK_ADDRESS = 1;
+
+    private static final int SUCCESSOR_COUNT = 0;
+
+    @Override
+    protected int inputCount() {
+        return super.inputCount() + INPUT_COUNT;
+    }
+
+    @Override
+    protected int successorCount() {
+        return super.successorCount() + SUCCESSOR_COUNT;
+    }
+
+    /**
+     * The instruction producing the object locked or unlocked by this instruction.
+     */
+     public Value object() {
+        return (Value) inputs().get(super.inputCount() + INPUT_OBJECT);
+    }
+
+    public Value setObject(Value n) {
+        return (Value) inputs().set(super.inputCount() + INPUT_OBJECT, n);
+    }
+
+    /**
+     * The instruction producing the address of the lock object.
+     */
+    public Value lockAddress() {
+        return (Value) inputs().get(super.inputCount() + INPUT_LOCK_ADDRESS);
+    }
+
+    public Value setLockAddress(Value n) {
+        return (Value) inputs().set(super.inputCount() + INPUT_LOCK_ADDRESS, n);
+    }
+
+    /**
+     * The lock number of this monitor access.
+     */
+    public final int lockNumber;
+
+    /**
+     * Creates a new AccessMonitor instruction.
+     *
+     * @param object the instruction producing the object
+     * @param lockAddress the address of the on-stack lock object or {@code null} if the runtime does not place locks on the stack
+     * @param stateBefore the state before executing the monitor operation
+     * @param lockNumber the number of the lock being acquired
+     * @param inputCount
+     * @param successorCount
+     * @param graph
+     */
+    public AccessMonitor(Value object, Value lockAddress, int lockNumber, int inputCount, int successorCount, Graph graph) {
+        super(CiKind.Illegal, inputCount + INPUT_COUNT, successorCount + SUCCESSOR_COUNT, graph);
+        this.lockNumber = lockNumber;
+        setObject(object);
+        setLockAddress(lockAddress);
+    }
+}