/*******************************************************************************
* 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.ssa;
/**
* A return instruction.
*/
public class SSAReturnInstruction extends SSAInstruction {
/**
* value number of the result. By convention result == -1 means returns void.
*/
private final int result;
private final boolean isPrimitive;
public SSAReturnInstruction(int iindex, int result, boolean isPrimitive) {
super(iindex);
this.result = result;
this.isPrimitive = isPrimitive;
}
public SSAReturnInstruction(int iindex) {
super(iindex);
this.result = -1;
this.isPrimitive = false;
}
@Override
public SSAInstruction copyForSSA(SSAInstructionFactory insts, int[] defs, int[] uses) {
if (result == -1)
return insts.ReturnInstruction(iindex);
else {
if (uses != null && uses.length != 1) {
throw new IllegalArgumentException("invalid uses. must have exactly one use.");
}
return insts.ReturnInstruction(iindex, uses == null ? result : uses[0], isPrimitive);
}
}
@Override
public String toString(SymbolTable table) {
if (result == -1) {
return "return";
} else {
return "return " + getValueString(table, result);
}
}
/**
* @see com.ibm.wala.ssa.SSAInstruction#visit(IVisitor)
* @throws IllegalArgumentException if v is null
*/
@Override
public void visit(IVisitor v) {
if (v == null) {
throw new IllegalArgumentException("v is null");
}
v.visitReturn(this);
}
/**
* @see com.ibm.wala.ssa.SSAInstruction#getNumberOfUses()
*/
@Override
public int getNumberOfUses() {
return (result == -1) ? 0 : 1;
}
/**
* @see com.ibm.wala.ssa.SSAInstruction#getUse(int)
*/
@Override
public int getUse(int j) {
if (j != 0) {
throw new IllegalArgumentException("illegal j: " + j);
}
return result;
}
/**
* @return true iff this return instruction returns a primitive value
*/
public boolean returnsPrimitiveType() {
return isPrimitive;
}
public int getResult() {
return result;
}
public boolean returnsVoid() {
return result == -1;
}
@Override
public int hashCode() {
return result * 8933;
}
/*
* @see com.ibm.wala.ssa.Instruction#isFallThrough()
*/
@Override
public boolean isFallThrough() {
return false;
}
}