154 lines
4.2 KiB
Java
154 lines
4.2 KiB
Java
/*******************************************************************************
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* Copyright (c) 2002,2006 IBM Corporation.
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* All rights reserved. This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License v1.0
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* which accompanies this distribution, and is available at
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* http://www.eclipse.org/legal/epl-v10.html
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*
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* Contributors:
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* IBM Corporation - initial API and implementation
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*******************************************************************************/
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package com.ibm.wala.shrikeBT;
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import java.util.Arrays;
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/**
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* This instruction represents all forms of switch instructions.
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*/
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public final class SwitchInstruction extends Instruction {
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final private int[] casesAndLabels;
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final private int defaultLabel;
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protected SwitchInstruction(short opcode, int[] casesAndLabels, int defaultLabel) {
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super(opcode);
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this.casesAndLabels = casesAndLabels;
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this.defaultLabel = defaultLabel;
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}
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/**
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* @return the label which is branched to if none of the cases match
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*/
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public int getDefaultLabel() {
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return defaultLabel;
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}
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/**
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* @return an array of flattened (case, label) pairs, sorted in increasing order by case
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*/
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public int[] getCasesAndLabels() {
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return casesAndLabels;
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}
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/**
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* Make a switch instruction.
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*
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* @param casesAndLabels an array of flattened (case, label) pairs, sorted in increasing order by case
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* @param defaultLabel the default label to branch to if no cases match
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* @throws IllegalArgumentException if casesAndLabels is null
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*/
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public static SwitchInstruction make(int[] casesAndLabels, int defaultLabel) {
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if (casesAndLabels == null) {
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throw new IllegalArgumentException("casesAndLabels is null");
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}
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short opcode = OP_tableswitch;
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for (int i = 2; i < casesAndLabels.length; i += 2) {
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int curCase = casesAndLabels[i];
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int lastCase = casesAndLabels[i - 2];
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if (curCase <= lastCase) {
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throw new IllegalArgumentException("Cases and labels array must be sorted by case");
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}
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if (curCase != lastCase + 1) {
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opcode = OP_lookupswitch;
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}
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}
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if (casesAndLabels.length == 0) {
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opcode = OP_lookupswitch;
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}
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return new SwitchInstruction(opcode, casesAndLabels, defaultLabel);
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}
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@Override
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public boolean isFallThrough() {
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return false;
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}
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@Override
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public int[] getBranchTargets() {
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int[] r = new int[casesAndLabels.length / 2 + 1];
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r[0] = defaultLabel;
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for (int i = 1; i < r.length; i++) {
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r[i] = casesAndLabels[(i - 1) * 2 + 1];
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}
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return r;
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}
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@Override
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public IInstruction redirectTargets(int[] targetMap) throws IllegalArgumentException {
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if (targetMap == null) {
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throw new IllegalArgumentException("targetMap is null");
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}
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try {
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int[] cs = new int[casesAndLabels.length];
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for (int i = 0; i < cs.length; i += 2) {
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cs[i] = casesAndLabels[i];
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cs[i + 1] = targetMap[casesAndLabels[i + 1]];
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}
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return make(cs, targetMap[defaultLabel]);
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} catch (ArrayIndexOutOfBoundsException e) {
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throw new IllegalArgumentException("Illegal target map", e);
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}
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}
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@Override
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public boolean equals(Object o) {
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if (o instanceof SwitchInstruction) {
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SwitchInstruction i = (SwitchInstruction) o;
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return i.defaultLabel == defaultLabel && Arrays.equals(i.casesAndLabels, casesAndLabels);
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} else {
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return false;
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}
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}
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@Override
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public int hashCode() {
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int h = defaultLabel * 1348091 + 111311;
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for (int i = 0; i < casesAndLabels.length; i++) {
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h += (i * 9301 + 38101) * casesAndLabels[i];
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}
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return h;
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}
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@Override
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public int getPoppedCount() {
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return 1;
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}
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@Override
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public String toString() {
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StringBuffer b = new StringBuffer("Switch(");
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b.append(defaultLabel);
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for (int i = 0; i < casesAndLabels.length; i++) {
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b.append(',');
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b.append(casesAndLabels[i]);
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}
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b.append(")");
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return b.toString();
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}
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@Override
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public void visit(IInstruction.Visitor v) throws IllegalArgumentException {
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if (v == null) {
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throw new IllegalArgumentException();
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}
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v.visitSwitch(this);
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}
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@Override
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public boolean isPEI() {
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return false;
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}
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} |