001    /*
002     *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003     *
004     *  This file is licensed to You under the Eclipse Public License (EPL);
005     *  You may not use this file except in compliance with the License. You
006     *  may obtain a copy of the License at
007     *
008     *      http://www.opensource.org/licenses/eclipse-1.0.php
009     *
010     *  See the COPYRIGHT.txt file distributed with this work for information
011     *  regarding copyright ownership.
012     */
013    package org.jikesrvm.compilers.opt.controlflow;
014    
015    import org.jikesrvm.compilers.opt.OperationNotImplementedException;
016    import org.jikesrvm.compilers.opt.OptOptions;
017    import org.jikesrvm.compilers.opt.driver.CompilerPhase;
018    import org.jikesrvm.compilers.opt.driver.OptimizingCompiler;
019    import org.jikesrvm.compilers.opt.ir.IR;
020    
021    /**
022     * Driver routine for dominator tree computation
023     */
024    public final class DominatorTreePhase extends CompilerPhase {
025    
026      @Override
027      public boolean shouldPerform(OptOptions options) {
028        // only perform if the dominators were successfully computed and
029        // one of the following options are set.
030        return options.SSA || options.PRINT_DOMINATORS;
031      }
032    
033      /**
034       * Returns "Dominator Tree"
035       * @return "Dominator Tree"
036       */
037      @Override
038      public String getName() {
039        return "Dominator Tree";
040      }
041    
042      /**
043       * Should the IR be printed before and/or after this phase?
044       * @param options controlling compiler options
045       * @param before query control
046       * @return {@code false}
047       */
048      @Override
049      public boolean printingEnabled(OptOptions options, boolean before) {
050        return false;
051      }
052    
053      @Override
054      public void perform(IR ir) {
055        // make sure the dominator computation completed successfully
056        if (!ir.HIRInfo.dominatorsAreComputed) {
057          return;
058        }
059        try {
060          DominatorTree.perform(ir, true);
061        } catch (OperationNotImplementedException e) {
062          if (ir.options.PRINT_DOMINATORS || ir.options.PRINT_SSA) {
063            OptimizingCompiler.report(e.getMessage());
064          }
065        }
066      }
067    }