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      1 /*
      2  * ProGuard -- shrinking, optimization, obfuscation, and preverification
      3  *             of Java bytecode.
      4  *
      5  * Copyright (c) 2002-2014 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.ClassConstant;
     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 import proguard.classfile.visitor.ClassVisitor;
     31 
     32 /**
     33  * This InstructionVisitor marks all classes that are used in an 'instanceof'
     34  * test by any of the instructions that it visits.
     35  *
     36  * @author Eric Lafortune
     37  */
     38 public class InstanceofClassMarker
     39 extends      SimplifiedVisitor
     40 implements   InstructionVisitor,
     41              ConstantVisitor,
     42              ClassVisitor
     43 {
     44     // Implementations for InstructionVisitor.
     45 
     46     public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {}
     47 
     48 
     49     public void visitConstantInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, ConstantInstruction constantInstruction)
     50     {
     51         if (constantInstruction.opcode == InstructionConstants.OP_INSTANCEOF)
     52         {
     53             clazz.constantPoolEntryAccept(constantInstruction.constantIndex, this);
     54         }
     55     }
     56 
     57 
     58     // Implementations for ConstantVisitor.
     59 
     60     public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
     61     {
     62         classConstant.referencedClassAccept(this);
     63     }
     64 
     65 
     66     // Implementations for ClassVisitor.
     67 
     68     public void visitLibraryClass(LibraryClass libraryClass) {}
     69 
     70     public void visitProgramClass(ProgramClass programClass)
     71     {
     72         setInstanceofed(programClass);
     73     }
     74 
     75 
     76     // Small utility methods.
     77 
     78     private static void setInstanceofed(Clazz clazz)
     79     {
     80         ClassOptimizationInfo info = ClassOptimizationInfo.getClassOptimizationInfo(clazz);
     81         if (info != null)
     82         {
     83             info.setInstanceofed();
     84         }
     85     }
     86 
     87 
     88     public static boolean isInstanceofed(Clazz clazz)
     89     {
     90         ClassOptimizationInfo info = ClassOptimizationInfo.getClassOptimizationInfo(clazz);
     91         return info == null || info.isInstanceofed();
     92     }
     93 }