InstanceofClassMarker.java revision db267bc191f906f55eaef21a27110cce2ec57fdf 
1/*
2 * ProGuard -- shrinking, optimization, obfuscation, and preverification
3 *             of Java bytecode.
4 *
5 * Copyright (c) 2002-2009 Eric Lafortune (eric@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 */
21package proguard.optimize.info;
22
23import proguard.classfile.*;
24import proguard.classfile.attribute.CodeAttribute;
25import proguard.classfile.constant.ClassConstant;
26import proguard.classfile.constant.visitor.ConstantVisitor;
27import proguard.classfile.instruction.*;
28import proguard.classfile.instruction.visitor.InstructionVisitor;
29import proguard.classfile.util.SimplifiedVisitor;
30import 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 */
38public class InstanceofClassMarker
39extends      SimplifiedVisitor
40implements   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}