--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.jvmci.meta/src/com/oracle/jvmci/meta/LocationIdentity.java	Wed May 27 00:36:16 2015 +0200
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2011, 2012, 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.jvmci.meta;
+
+import java.util.*;
+
+// JaCoCo Exclude
+
+/**
+ * Marker interface for location identities. Apart from the special values {@link #ANY_LOCATION} and
+ * {@link #FINAL_LOCATION}, a different location identity of two memory accesses guarantees that the
+ * two accesses do not interfere.
+ *
+ * Clients of {@link LocationIdentity} must use {@link #equals(Object)}, not {@code ==}, when
+ * comparing two {@link LocationIdentity} values for equality. Likewise, they must not use
+ * {@link IdentityHashMap}s with {@link LocationIdentity} values as keys.
+ */
+public abstract class LocationIdentity {
+
+    /**
+     * Denotes any location. A write to such a location kills all values in a memory map during an
+     * analysis of memory accesses. A read from this location cannot be moved or coalesced with
+     * other reads because its interaction with other reads is not known.
+     */
+    private static final LocationIdentity ANY_LOCATION = NamedLocationIdentity.mutable("ANY_LOCATION");
+
+    /**
+     * Denotes the location of a value that is guaranteed to be unchanging.
+     */
+    public static final LocationIdentity FINAL_LOCATION = NamedLocationIdentity.immutable("FINAL_LOCATION");
+
+    /**
+     * Denotes the location of the length field of a Java array.
+     */
+    public static final LocationIdentity ARRAY_LENGTH_LOCATION = NamedLocationIdentity.immutable("[].length");
+
+    public static LocationIdentity any() {
+        return ANY_LOCATION;
+    }
+
+    /**
+     * Denotes a location is unchanging in all cases. Not that this is different than the Java
+     * notion of final which only requires definite assignment.
+     */
+    public abstract boolean isImmutable();
+
+    public final boolean isMutable() {
+        return !isImmutable();
+    }
+
+    public final boolean isAny() {
+        return this == ANY_LOCATION;
+    }
+
+    public final boolean isSingle() {
+        return this != ANY_LOCATION;
+    }
+
+    public final boolean overlaps(LocationIdentity other) {
+        return isAny() || other.isAny() || this.equals(other);
+    }
+}