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      1 /*
      2  * ProGuard -- shrinking, optimization, obfuscation, and preverification
      3  *             of Java bytecode.
      4  *
      5  * Copyright (c) 2002-2009 Eric Lafortune (eric (at) graphics.cornell.edu)
      6  *
      7  * This program is free software; you can redistribute it and/or modify it
      8  * under the terms of the GNU General Public License as published by the Free
      9  * Software Foundation; either version 2 of the License, or (at your option)
     10  * any later version.
     11  *
     12  * This program is distributed in the hope that it will be useful, but WITHOUT
     13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
     14  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
     15  * more details.
     16  *
     17  * You should have received a copy of the GNU General Public License along
     18  * with this program; if not, write to the Free Software Foundation, Inc.,
     19  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
     20  */
     21 package proguard.optimize.info;
     22 
     23 import proguard.classfile.*;
     24 import proguard.classfile.attribute.CodeAttribute;
     25 import proguard.classfile.constant.RefConstant;
     26 import proguard.classfile.constant.visitor.ConstantVisitor;
     27 import proguard.classfile.instruction.*;
     28 import proguard.classfile.instruction.visitor.InstructionVisitor;
     29 import proguard.classfile.util.SimplifiedVisitor;
     30 
     31 /**
     32  * This InstructionVisitor marks all methods that invoke super methods (other
     33  * than initializers) from the instructions that it visits.
     34  *
     35  * @author Eric Lafortune
     36  */
     37 public class SuperInvocationMarker
     38 extends      SimplifiedVisitor
     39 implements   InstructionVisitor,
     40              ConstantVisitor
     41 {
     42     private boolean invokesSuperMethods;
     43 
     44 
     45     // Implementations for InstructionVisitor.
     46 
     47     public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {}
     48 
     49 
     50     public void visitConstantInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, ConstantInstruction constantInstruction)
     51     {
     52         if (constantInstruction.opcode == InstructionConstants.OP_INVOKESPECIAL)
     53         {
     54             invokesSuperMethods = false;
     55 
     56             clazz.constantPoolEntryAccept(constantInstruction.constantIndex, this);
     57 
     58             if (invokesSuperMethods)
     59             {
     60                 setInvokesSuperMethods(method);
     61             }
     62         }
     63     }
     64 
     65 
     66     // Implementations for ConstantVisitor.
     67 
     68     public void visitAnyMethodrefConstant(Clazz clazz, RefConstant refConstant)
     69     {
     70         invokesSuperMethods =
     71             !clazz.equals(refConstant.referencedClass) &&
     72             !refConstant.getName(clazz).equals(ClassConstants.INTERNAL_METHOD_NAME_INIT);
     73     }
     74 
     75 
     76     // Small utility methods.
     77 
     78     private static void setInvokesSuperMethods(Method method)
     79     {
     80         MethodOptimizationInfo info = MethodOptimizationInfo.getMethodOptimizationInfo(method);
     81         if (info != null)
     82         {
     83             info.setInvokesSuperMethods();
     84         }
     85     }
     86 
     87 
     88     public static boolean invokesSuperMethods(Method method)
     89     {
     90         MethodOptimizationInfo info = MethodOptimizationInfo.getMethodOptimizationInfo(method);
     91         return info == null || info.invokesSuperMethods();
     92     }
     93 }
     94