/*******************************************************************************
* Copyright (c) 2002,2006 IBM Corporation.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package com.ibm.wala.shrikeBT;
/**
* This class represents conditional branches. A conditional branch tests two integers or two object references for some
* relationship, and takes the branch if the relationship holds.
*/
public final class ConditionalBranchInstruction extends Instruction implements IConditionalBranchInstruction {
final private int label;
protected ConditionalBranchInstruction(short opcode, int label) {
super(opcode);
this.label = label;
}
public static ConditionalBranchInstruction make(String type, Operator operator, int label) throws IllegalArgumentException {
int t = Util.getTypeIndex(type);
short opcode;
switch (t) {
case TYPE_int_index:
opcode = (short) (OP_if_icmpeq + (operator.ordinal() - Operator.EQ.ordinal()));
break;
case TYPE_Object_index:
if (operator != Operator.EQ && operator != Operator.NE) {
throw new IllegalArgumentException("Cannot test for condition " + operator + " on a reference");
}
opcode = (short) (OP_if_acmpeq + (operator.ordinal() - Operator.EQ.ordinal()));
break;
default:
throw new IllegalArgumentException("Cannot conditionally branch on a value of type " + type);
}
return make(opcode, label);
}
// Relax from private to public by Xiangyu, to create ifeq
public static ConditionalBranchInstruction make(short opcode, int label) throws IllegalArgumentException {
if (opcode < OP_ifeq || opcode > OP_if_acmpne) {
throw new IllegalArgumentException("Illegal opcode: " + opcode);
}
return new ConditionalBranchInstruction(opcode, label);
}
@Override
public boolean equals(Object o) {
if (o instanceof ConditionalBranchInstruction) {
ConditionalBranchInstruction i = (ConditionalBranchInstruction) o;
return i.opcode == opcode && i.label == label;
} else {
return false;
}
}
@Override
public String toString() {
return "ConditionalBranch(" + getType() + "," + getOperator() + "," + label + ")";
}
@Override
public int[] getBranchTargets() {
int[] r = { label };
return r;
}
@Override
public int getTarget() {
return label;
}
@Override
public IInstruction redirectTargets(int[] targetMap) throws IllegalArgumentException {
if (targetMap == null) {
throw new IllegalArgumentException("targetMap is null");
}
try {
return make(opcode, targetMap[label]);
} catch (ArrayIndexOutOfBoundsException e) {
throw new IllegalArgumentException("bad target map", e);
}
}
@Override
public Operator getOperator() {
if (opcode < OP_if_acmpeq) {
return Operator.values()[opcode - OP_if_icmpeq];
} else {
return Operator.values()[opcode - OP_if_acmpeq];
}
}
@Override
public String getType() {
return opcode < OP_if_acmpeq ? TYPE_int : TYPE_Object;
}
@Override
public int hashCode() {
return 30190 * opcode + 384101 * label;
}
@Override
public int getPoppedCount() {
// Xiangyu, to support if_eq (if_ne)...
if (opcode >= Constants.OP_ifeq && opcode <= Constants.OP_ifle)
return 1;
return 2;
}
@Override
public void visit(IInstruction.Visitor v) throws NullPointerException {
v.visitConditionalBranch(this);
}
@Override
public boolean isPEI() {
return false;
}
}