Home | History | Annotate | Download | only in analysis 
      1 /***
      2  * ASM: a very small and fast Java bytecode manipulation framework
      3  * Copyright (c) 2000-2005 INRIA, France Telecom
      4  * All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  * 3. Neither the name of the copyright holders nor the names of its
     15  *    contributors may be used to endorse or promote products derived from
     16  *    this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
     19  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     21  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
     22  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
     28  * THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 package org.objectweb.asm.tree.analysis;
     31 
     32 import java.util.ArrayList;
     33 import java.util.List;
     34 
     35 import org.objectweb.asm.Label;
     36 import org.objectweb.asm.tree.JumpInsnNode;
     37 
     38 /**
     39  * A method subroutine (corresponds to a JSR instruction).
     40  *
     41  * @author Eric Bruneton
     42  */
     43 class Subroutine {
     44 
     45     Label start;
     46 
     47     boolean[] access;
     48 
     49     List callers;
     50 
     51     private Subroutine() {
     52     }
     53 
     54     public Subroutine(
     55         final Label start,
     56         final int maxLocals,
     57         final JumpInsnNode caller)
     58     {
     59         this.start = start;
     60         this.access = new boolean[maxLocals];
     61         this.callers = new ArrayList();
     62         callers.add(caller);
     63     }
     64 
     65     public Subroutine copy() {
     66         Subroutine result = new Subroutine();
     67         result.start = start;
     68         result.access = new boolean[access.length];
     69         System.arraycopy(access, 0, result.access, 0, access.length);
     70         result.callers = new ArrayList(callers);
     71         return result;
     72     }
     73 
     74     public boolean merge(final Subroutine subroutine, boolean checkOverlap)
     75             throws AnalyzerException
     76     {
     77         if (checkOverlap && subroutine.start != start) {
     78             throw new AnalyzerException("Overlapping sub routines");
     79         }
     80         boolean changes = false;
     81         for (int i = 0; i < access.length; ++i) {
     82             if (subroutine.access[i] && !access[i]) {
     83                 access[i] = true;
     84                 changes = true;
     85             }
     86         }
     87         for (int i = 0; i < subroutine.callers.size(); ++i) {
     88             Object caller = subroutine.callers.get(i);
     89             if (!callers.contains(caller)) {
     90                 callers.add(caller);
     91                 changes = true;
     92             }
     93         }
     94         return changes;
     95     }
     96 }