--- /dev/null	2015-10-08 07:24:58.000000000 -1000
+++ new/src/jdk.vm.ci/share/classes/jdk.vm.ci.code/src/jdk/vm/ci/code/StackSlot.java	2015-10-08 07:24:58.000000000 -1000
@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2010, 2014, 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.code;
+
+import jdk.vm.ci.meta.*;
+
+/**
+ * Represents a compiler spill slot or an outgoing stack-based argument in a method's frame or an
+ * incoming stack-based argument in a method's {@linkplain #isInCallerFrame() caller's frame}.
+ */
+public final class StackSlot extends StackSlotValue {
+
+    private final int offset;
+    private final boolean addFrameSize;
+
+    /**
+     * Gets a {@link StackSlot} instance representing a stack slot at a given index holding a value
+     * of a given kind.
+     *
+     * @param kind The kind of the value stored in the stack slot.
+     * @param offset The offset of the stack slot (in bytes)
+     * @param addFrameSize Specifies if the offset is relative to the stack pointer, or the
+     *            beginning of the frame (stack pointer + total frame size).
+     */
+    public static StackSlot get(LIRKind kind, int offset, boolean addFrameSize) {
+        assert addFrameSize || offset >= 0;
+        return new StackSlot(kind, offset, addFrameSize);
+    }
+
+    /**
+     * Private constructor to enforce use of {@link #get(LIRKind, int, boolean)} so that a cache can
+     * be used.
+     */
+    private StackSlot(LIRKind kind, int offset, boolean addFrameSize) {
+        super(kind);
+        this.offset = offset;
+        this.addFrameSize = addFrameSize;
+    }
+
+    /**
+     * Gets the offset of this stack slot, relative to the stack pointer.
+     *
+     * @return The offset of this slot (in bytes).
+     */
+    public int getOffset(int totalFrameSize) {
+        assert totalFrameSize > 0 || !addFrameSize;
+        int result = offset + (addFrameSize ? totalFrameSize : 0);
+        assert result >= 0;
+        return result;
+    }
+
+    public boolean isInCallerFrame() {
+        return addFrameSize && offset >= 0;
+    }
+
+    public int getRawOffset() {
+        return offset;
+    }
+
+    public boolean getRawAddFrameSize() {
+        return addFrameSize;
+    }
+
+    @Override
+    public String toString() {
+        if (!addFrameSize) {
+            return "out:" + offset + getKindSuffix();
+        } else if (offset >= 0) {
+            return "in:" + offset + getKindSuffix();
+        } else {
+            return "stack:" + (-offset) + getKindSuffix();
+        }
+    }
+
+    /**
+     * Gets this stack slot used to pass an argument from the perspective of a caller.
+     */
+    public StackSlot asOutArg() {
+        assert offset >= 0;
+        if (addFrameSize) {
+            return get(getLIRKind(), offset, false);
+        }
+        return this;
+    }
+
+    /**
+     * Gets this stack slot used to pass an argument from the perspective of a callee.
+     */
+    public StackSlot asInArg() {
+        assert offset >= 0;
+        if (!addFrameSize) {
+            return get(getLIRKind(), offset, true);
+        }
+        return this;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 37;
+        int result = super.hashCode();
+        result = prime * result + (addFrameSize ? 1231 : 1237);
+        result = prime * result + offset;
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof StackSlot) {
+            StackSlot other = (StackSlot) obj;
+            return super.equals(obj) && addFrameSize == other.addFrameSize && offset == other.offset;
+        }
+        return false;
+    }
+}