1 /*
   2  * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package jdk.vm.ci.meta;
  24 
  25 /**
  26  * Maps bytecode indexes to source line numbers.
  27  *
  28  * @see "https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7.12"
  29  */
  30 public class LineNumberTable {
  31 
  32     private final int[] lineNumbers;
  33     private final int[] bcis;
  34 
  35     /**
  36      *
  37      * @param lineNumbers an array of source line numbers. This array is now owned by this object
  38      *            and should not be mutated by the caller.
  39      * @param bcis an array of bytecode indexes the same length at {@code lineNumbers} whose entries
  40      *            are sorted in ascending order. This array is now owned by this object and must not
  41      *            be mutated by the caller.
  42      */
  43     @SuppressFBWarnings(value = "EI_EXPOSE_REP2", justification = "caller transfers ownership of `lineNumbers` and `bcis`")
  44     public LineNumberTable(int[] lineNumbers, int[] bcis) {
  45         assert bcis.length == lineNumbers.length;
  46         this.lineNumbers = lineNumbers;
  47         this.bcis = bcis;
  48     }
  49 
  50     /**
  51      * Gets a source line number for bytecode index {@code atBci}.
  52      */
  53     public int getLineNumber(int atBci) {
  54         for (int i = 0; i < this.bcis.length - 1; i++) {
  55             if (this.bcis[i] <= atBci && atBci < this.bcis[i + 1]) {
  56                 return lineNumbers[i];
  57             }
  58         }
  59         return lineNumbers[lineNumbers.length - 1];
  60     }
  61 
  62     /**
  63      * Gets a copy of the array of line numbers that was passed to this object's constructor.
  64      */
  65     public int[] getLineNumbers() {
  66         return lineNumbers.clone();
  67     }
  68 
  69     /**
  70      * Gets a copy of the array of bytecode indexes that was passed to this object's constructor.
  71      */
  72     public int[] getBcis() {
  73         return bcis.clone();
  74     }
  75 }