PostDominatorsAnalysis.java

/*
 * Bytecode Analysis Framework
 * Copyright (C) 2003,2004 University of Maryland
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs.ba;

/**
 * Dataflow analysis to compute postdominator sets for a CFG.
 * 
 * @author David Hovemeyer
 * @see CFG
 * @see AbstractDominatorsAnalysis
 */
public class PostDominatorsAnalysis extends AbstractDominatorsAnalysis {
    final private ReverseDepthFirstSearch rdfs;

    final private DepthFirstSearch dfs;

    /**
     * Constructor.
     * 
     * @param cfg
     *            the CFG to compute dominator relationships for
     * @param rdfs
     *            the ReverseDepthFirstSearch on the CFG
     * @param dfs
     *            the DepthFirstSearch on the CFG
     * @param edgeChooser
     *            EdgeChooser to choose which Edges to consider significant
     */
    protected PostDominatorsAnalysis(CFG cfg, ReverseDepthFirstSearch rdfs, DepthFirstSearch dfs, EdgeChooser edgeChooser) {
        super(cfg, edgeChooser);
        this.rdfs = rdfs;
        this.dfs = dfs;
    }

    /**
     * Constructor.
     * 
     * @param cfg
     *            the CFG to compute dominator relationships for
     * @param rdfs
     *            the ReverseDepthFirstSearch on the CFG
     * @param dfs
     *            the DepthFirstSearch on the CFG
     * @param ignoreExceptionEdges
     *            true if exception edges should be ignored
     */
    protected PostDominatorsAnalysis(CFG cfg, ReverseDepthFirstSearch rdfs, DepthFirstSearch dfs, boolean ignoreExceptionEdges) {
        super(cfg, ignoreExceptionEdges);
        this.rdfs = rdfs;
        this.dfs = dfs;
    }

    public boolean isForwards() {
        return false;
    }

    public BlockOrder getBlockOrder(CFG cfg) {
        return new ReverseDFSOrder(cfg, rdfs, dfs);
    }

    // public static void main(String[] args) throws Exception {
    // if (args.length != 1) {
    // System.err.println("Usage: " + PostDominatorsAnalysis.class.getName() +
    // " <classfile>");
    // System.exit(1);
    // }
    //
    // DataflowTestDriver<BitSet, PostDominatorsAnalysis> driver =
    // new DataflowTestDriver<BitSet, PostDominatorsAnalysis>() {
    //
    // /* (non-Javadoc)
    // * @see
    // edu.umd.cs.findbugs.ba.DataflowTestDriver#createDataflow(edu.umd.cs.findbugs.ba.ClassContext,
    // org.apache.bcel.classfile.Method)
    // */
    // @Override
    // public Dataflow<BitSet, PostDominatorsAnalysis>
    // createDataflow(ClassContext classContext, Method method) throws
    // CFGBuilderException, DataflowAnalysisException {
    // CFG cfg = classContext.getCFG(method);
    // ReverseDepthFirstSearch rdfs =
    // classContext.getReverseDepthFirstSearch(method);
    //
    // PostDominatorsAnalysis analysis =
    // new PostDominatorsAnalysis(cfg, rdfs,
    // classContext.getDepthFirstSearch(method),
    // SystemProperties.getBoolean("dominators.ignoreexceptionedges"));
    //
    // Dataflow<BitSet, PostDominatorsAnalysis> dataflow =
    // new Dataflow<BitSet, PostDominatorsAnalysis>(cfg, analysis);
    //
    // dataflow.execute();
    //
    // return dataflow;
    // }
    //
    // };
    //
    // driver.execute(args[0]);
    // }
}

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