/*******************************************************************************
* 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.util.graph.dominators;
import com.ibm.wala.util.graph.NumberedGraph;
/**
* Calculate dominators using Langauer and Tarjan's fastest algorithm. TOPLAS
* 1(1), July 1979. This implementation uses path compression and results in a
* O(e * alpha(e,n)) complexity, where e is the number of edges in the CFG and n
* is the number of nodes.
*
* Sources: TOPLAS article, Muchnick book
*/
public class NumberedDominators<T> extends Dominators<T> {
public NumberedDominators(NumberedGraph<T> G, T root) throws IllegalArgumentException {
super(G, root);
this.infoMap = new Object[G.getMaxNumber() + 1];
for (T n : G) {
infoMap[G.getNumber(n)] = new DominatorInfo(n);
}
analyze();
}
@Override
public NumberedGraph<T> getGraph() {
return (NumberedGraph<T>) G;
}
/*
* Look-aside table for DominatorInfo objects
*/
private final Object[] infoMap;
@SuppressWarnings("unchecked")
@Override
protected final DominatorInfo getInfo(T node) {
assert node != null;
return (DominatorInfo) infoMap[getGraph().getNumber(node)];
}
}