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view graal/com.oracle.max.cri/src/com/sun/cri/bytecode/BytecodeSwitch.java @ 4149:cf4de9cc1268
Integrated latest mxtool updates.
author | Doug Simon <doug.simon@oracle.com> |
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date | Tue, 20 Dec 2011 10:36:44 +0100 |
parents | bc8527f3071c |
children |
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/* * 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.cri.bytecode; /** * An abstract class that provides the state and methods common to {@link Bytecodes#LOOKUPSWITCH} * and {@link Bytecodes#TABLESWITCH} instructions. */ public abstract class BytecodeSwitch { /** * The {@link BytecodeStream} containing bytecode array or {@code null} if {@link #code} is not {@code null}. */ private final BytecodeStream stream; /** * The bytecode array or {@code null} if {@link #stream} is not {@code null}. */ private final byte[] code; /** * Index of start of switch instruction. */ protected final int bci; /** * Index of the start of the additional data for the switch instruction, aligned to a multiple of four from the method start. */ protected final int alignedBci; /** * Constructor for a {@link BytecodeStream}. * @param stream the {@code BytecodeStream} containing the switch instruction * @param bci the index in the stream of the switch instruction */ public BytecodeSwitch(BytecodeStream stream, int bci) { this.alignedBci = (bci + 4) & 0xfffffffc; this.stream = stream; this.code = null; this.bci = bci; } /** * Constructor for a bytecode array. * @param code the bytecode array containing the switch instruction. * @param bci the index in the array of the switch instruction */ public BytecodeSwitch(byte[] code, int bci) { this.alignedBci = (bci + 4) & 0xfffffffc; this.stream = null; this.code = code; this.bci = bci; } /** * Gets the current bytecode index. * @return the current bytecode index */ public int bci() { return bci; } /** * Gets the index of the instruction denoted by the {@code i}'th switch target. * @param i index of the switch target * @return the index of the instruction denoted by the {@code i}'th switch target */ public int targetAt(int i) { return bci + offsetAt(i); } /** * Gets the index of the instruction for the default switch target. * @return the index of the instruction for the default switch target */ public int defaultTarget() { return bci + defaultOffset(); } /** * Gets the offset from the start of the switch instruction to the default switch target. * @return the offset to the default switch target */ public abstract int defaultOffset(); /** * Gets the key at {@code i}'th switch target index. * @param i the switch target index * @return the key at {@code i}'th switch target index */ public abstract int keyAt(int i); /** * Gets the offset from the start of the switch instruction for the {@code i}'th switch target. * @param i the switch target index * @return the offset to the {@code i}'th switch target */ public abstract int offsetAt(int i); /** * Gets the number of switch targets. * @return the number of switch targets */ public abstract int numberOfCases(); /** * Gets the total size in bytes of the switch instruction. * @return the total size in bytes of the switch instruction */ public abstract int size(); /** * Reads the signed value at given bytecode index. * @param readBci the start index of the value to retrieve * @return the signed, 4-byte value in the bytecode array starting at {@code bci} */ protected int readWord(int readBci) { if (code != null) { return Bytes.beS4(code, readBci); } return stream.readInt(readBci); } }