--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.max.cri/src/com/sun/cri/ci/CiStackSlot.java	Sat Dec 17 19:59:18 2011 +0100
@@ -0,0 +1,195 @@
+/*
+ * Copyright (c) 2010, 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.cri.ci;
+
+/**
+ * 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 #inCallerFrame() caller's frame}.
+ */
+public final class CiStackSlot extends CiValue {
+
+    /**
+     * @see CiStackSlot#index()
+     */
+    private final int index;
+
+    /**
+     * Gets a {@link CiStackSlot} instance representing a stack slot in the current frame
+     * at a given index holding a value of a given kind.
+     *
+     * @param kind the kind of the value stored in the stack slot
+     * @param index the index of the stack slot
+     */
+    public static CiStackSlot get(CiKind kind, int index) {
+        return get(kind, index, false);
+    }
+
+    /**
+     * Gets a {@link CiStackSlot} 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 index the index of the stack slot
+     * @param inCallerFrame specifies if the slot is in the current frame or in the caller's frame
+     */
+    public static CiStackSlot get(CiKind kind, int index, boolean inCallerFrame) {
+        assert kind.stackKind() == kind;
+        CiStackSlot[][] cache = inCallerFrame ? CALLER_FRAME_CACHE : CACHE;
+        CiStackSlot[] slots = cache[kind.ordinal()];
+        CiStackSlot slot;
+        if (index < slots.length) {
+            slot = slots[index];
+        } else {
+            slot = new CiStackSlot(kind, inCallerFrame ? -(index + 1) : index);
+        }
+        assert slot.inCallerFrame() == inCallerFrame;
+        return slot;
+    }
+
+    /**
+     * Private constructor to enforce use of {@link #get(CiKind, int)} so that the
+     * shared instance {@linkplain #CACHE cache} is used.
+     */
+    private CiStackSlot(CiKind kind, int index) {
+        super(kind);
+        this.index = index;
+    }
+
+    /**
+     * Gets the index of this stack slot. If this is a spill slot or outgoing stack argument to a call,
+     * then the index is relative to the current frame pointer. Otherwise this is an incoming stack
+     * argument and the index is relative to the caller frame pointer.
+     *
+     * @return the index of this slot
+     * @see #inCallerFrame()
+     */
+    public int index() {
+        return index < 0 ? -(index + 1) : index;
+    }
+
+    @Override
+    public int hashCode() {
+        return kind.ordinal() + index;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == this) {
+            return true;
+        }
+        if (o instanceof CiStackSlot) {
+            CiStackSlot l = (CiStackSlot) o;
+            return l.kind == kind && l.index == index;
+        }
+        return false;
+    }
+
+    @Override
+    public boolean equalsIgnoringKind(CiValue o) {
+        if (o == this) {
+            return true;
+        }
+        if (o instanceof CiStackSlot) {
+            CiStackSlot l = (CiStackSlot) o;
+            return l.index == index;
+        }
+        return false;
+    }
+
+    @Override
+    public String name() {
+        return (inCallerFrame() ? "caller-stack" : "stack:") + index();
+    }
+
+    /**
+     * Determines if this is a stack slot in the caller's frame.
+     */
+    public boolean inCallerFrame() {
+        return index < 0;
+    }
+
+    /**
+     * Gets this stack slot used to pass an argument from the perspective of a caller.
+     */
+    public CiStackSlot asOutArg() {
+        if (inCallerFrame()) {
+            return get(kind, index(), false);
+        }
+        return this;
+    }
+
+    /**
+     * Gets this stack slot used to pass an argument from the perspective of a callee.
+     */
+    public CiStackSlot asInArg() {
+        if (!inCallerFrame()) {
+            return get(kind, index(), true);
+        }
+        return this;
+    }
+
+    /**
+     * Default size of the cache to generate per kind.
+     */
+    private static final int CACHE_PER_KIND_SIZE = 100;
+
+    private static final int CALLER_FRAME_CACHE_PER_KIND_SIZE = 10;
+
+    /**
+     * A cache of {@linkplain #inCallerFrame() non-caller-frame} stack slots.
+     */
+    private static final CiStackSlot[][] CACHE = makeCache(CACHE_PER_KIND_SIZE, false);
+
+    /**
+     * A cache of {@linkplain #inCallerFrame() caller-frame} stack slots.
+     */
+    private static final CiStackSlot[][] CALLER_FRAME_CACHE = makeCache(CALLER_FRAME_CACHE_PER_KIND_SIZE, true);
+
+    private static CiStackSlot[][] makeCache(int cachePerKindSize, boolean inCallerFrame) {
+        CiStackSlot[][] cache = new CiStackSlot[CiKind.VALUES.length][];
+        cache[CiKind.Illegal.ordinal()] = makeCacheForKind(CiKind.Illegal, cachePerKindSize, inCallerFrame);
+        cache[CiKind.Int.ordinal()]     = makeCacheForKind(CiKind.Int, cachePerKindSize, inCallerFrame);
+        cache[CiKind.Long.ordinal()]    = makeCacheForKind(CiKind.Long, cachePerKindSize, inCallerFrame);
+        cache[CiKind.Float.ordinal()]   = makeCacheForKind(CiKind.Float, cachePerKindSize, inCallerFrame);
+        cache[CiKind.Double.ordinal()]  = makeCacheForKind(CiKind.Double, cachePerKindSize, inCallerFrame);
+        cache[CiKind.Object.ordinal()]  = makeCacheForKind(CiKind.Object, cachePerKindSize, inCallerFrame);
+        cache[CiKind.Jsr.ordinal()]     = makeCacheForKind(CiKind.Jsr, cachePerKindSize, inCallerFrame);
+        return cache;
+    }
+
+    /**
+     * Creates an array of {@code CiStackSlot} objects for a given {@link CiKind}.
+     * The {@link #index} values range from {@code 0} to {@code count - 1}.
+     *
+     * @param kind the {@code CiKind} of the stack slot
+     * @param count the size of the array to create
+     * @return the generated {@code CiStackSlot} array
+     */
+    private static CiStackSlot[] makeCacheForKind(CiKind kind, int count, boolean inCallerFrame) {
+        CiStackSlot[] slots = new CiStackSlot[count];
+        for (int i = 0; i < count; ++i) {
+            slots[i] = new CiStackSlot(kind, inCallerFrame ? -(i + 1) : i);
+        }
+        return slots;
+    }
+}