/*
* 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
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*/
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;
}
}