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.baseline;
014    
015    /**
016     * Profile data for a branch instruction.
017     */
018    public final class SwitchBranchProfile extends BranchProfile {
019    
020      /**
021       * The number of times that the different arms of a switch were
022       * taken. By convention, the default case is the last entry.
023       */
024      final float[] counts;
025    
026      /**
027       * @param _bci the bytecode index of the source branch instruction
028       * @param cs counts
029       * @param start idx of first entry in cs
030       * @param numEntries number of entries in cs for this switch
031       */
032      SwitchBranchProfile(int _bci, int[] cs, int start, int numEntries) {
033        super(_bci, sumCounts(cs, start, numEntries));
034        counts = new float[numEntries];
035        for (int i = 0; i < numEntries; i++) {
036          counts[i] = (float) cs[start + i];
037        }
038      }
039    
040      public float getDefaultProbability() {
041        return getProbability(counts.length - 1);
042      }
043    
044      public float getCaseProbability(int n) {
045        return getProbability(n);
046      }
047    
048      float getProbability(int n) {
049        if (freq > 0) {
050          return counts[n] / freq;
051        } else {
052          return 1.0f / counts.length;
053        }
054      }
055    
056      public String toString() {
057        String res = bci + "\tswitch     < " + (int) counts[0];
058        for (int i = 1; i < counts.length; i++) {
059          res += ", " + (int) counts[i];
060        }
061        return res + " >";
062      }
063    
064      private static float sumCounts(int[] counts, int start, int numEntries) {
065        float sum = 0.0f;
066        for (int i = start; i < start + numEntries; i++) {
067          sum += (float) counts[i];
068        }
069        return sum;
070      }
071    }