WALA/com.ibm.wala.shrike/src/com/ibm/wala/shrikeBT/ShiftInstruction.java

103 lines
2.7 KiB
Java

/*******************************************************************************
* 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;
/**
* ShiftInstructions are distinguished from BinaryOpInstructions because most binary operations in the JVM require both parameters
* to be the same type, but shifts always take one int parameter.
*/
public final class ShiftInstruction extends Instruction implements IShiftInstruction {
protected ShiftInstruction(short opcode) {
super(opcode);
}
private static final ShiftInstruction[] preallocated = preallocate();
private static ShiftInstruction[] preallocate() {
ShiftInstruction[] r = new ShiftInstruction[OP_lushr - OP_ishl + 1];
for (int i = 0; i < r.length; i++) {
r[i] = new ShiftInstruction((short) (i + OP_ishl));
}
return r;
}
public static ShiftInstruction make(String type, Operator operator) throws IllegalArgumentException {
if (operator == null) {
throw new IllegalArgumentException("operator is null");
}
int t = Util.getTypeIndex(type);
if (t < 0 || t > TYPE_long_index) {
throw new IllegalArgumentException("Cannot apply shift to type " + type);
}
return preallocated[(operator.ordinal() - Operator.SHL.ordinal()) * 2 + t];
}
@Override
public boolean equals(Object o) {
if (o instanceof ShiftInstruction) {
ShiftInstruction i = (ShiftInstruction) o;
return i.opcode == opcode;
} else {
return false;
}
}
@Override
public Operator getOperator() {
return Operator.values()[(opcode - OP_ishl) / 2];
}
@Override
public int hashCode() {
return opcode;
}
@Override
public int getPoppedCount() {
return 2;
}
@Override
public String getPushedType(String[] types) {
return getType();
}
@Override
public byte getPushedWordSize() {
return Util.getWordSize(getType());
}
@Override
public String getType() {
return indexedTypes[(opcode - OP_ishl) & 1];
}
@Override
public void visit(IInstruction.Visitor v) throws NullPointerException {
v.visitShift(this);
}
@Override
public String toString() {
return "Shift(" + getType() + "," + getOperator() + ")";
}
@Override
public boolean isPEI() {
return false;
}
@Override
public boolean isUnsigned() {
return false;
}
}