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.regalloc;
014    
015    import org.jikesrvm.compilers.opt.ir.IR;
016    
017    /**
018     * An object that returns an estimate of the relative cost of spilling a
019     * symbolic register.
020     *
021     * This implementation returns a cost of zero for all registers.
022     */
023    class BrainDeadSpillCost extends SpillCostEstimator {
024    
025      BrainDeadSpillCost(IR ir) {
026        calculate(ir);
027      }
028    
029      /**
030       * Calculate the estimated cost for each register.
031       * This brain-dead version does nothing.
032       */
033      void calculate(IR ir) {
034      }
035    }