BridgeMethodFixer.java revision 8a6199f0c36a778f22394364347a301b0b28e94b 
1/*
2 * ProGuard -- shrinking, optimization, obfuscation, and preverification
3 *             of Java bytecode.
4 *
5 * Copyright (c) 2002-2013 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.classfile.editor;
22
23import proguard.classfile.*;
24import proguard.classfile.attribute.*;
25import proguard.classfile.attribute.visitor.AttributeVisitor;
26import proguard.classfile.constant.*;
27import proguard.classfile.constant.visitor.ConstantVisitor;
28import proguard.classfile.instruction.*;
29import proguard.classfile.instruction.visitor.InstructionVisitor;
30import proguard.classfile.util.*;
31import proguard.classfile.visitor.*;
32
33/**
34 * This MemberVisitor fixes all inappropriate bridge access flags of the
35 * program methods that it visits, checking whether the methods to which they
36 * bridge have the same name. Some compilers, like in Eclipse and in later
37 * versions of JDK 1.6, complain if they can't find the method with the same
38 * name.
39 *
40 * @author Eric Lafortune
41 */
42public class BridgeMethodFixer
43extends      SimplifiedVisitor
44implements   MemberVisitor,
45             AttributeVisitor,
46             InstructionVisitor,
47             ConstantVisitor
48{
49    private static final boolean DEBUG = false;
50
51
52    // Return values for the visitor methods.
53    private String bridgedMethodName;
54
55
56    // Implementations for MemberVisitor.
57
58    public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod)
59    {
60        if ((programMethod.getAccessFlags() & ClassConstants.INTERNAL_ACC_BRIDGE) != 0)
61        {
62            programMethod.attributesAccept(programClass, this);
63        }
64    }
65
66
67    // Implementations for AttributeVisitor.
68
69    public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}
70
71
72    public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute)
73    {
74        // Go over the instructions of the bridge method.
75        codeAttribute.instructionsAccept(clazz, method, this);
76    }
77
78
79    // Implementations for InstructionVisitor.
80
81    public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {}
82
83
84    public void visitConstantInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, ConstantInstruction constantInstruction)
85    {
86        switch (constantInstruction.opcode)
87        {
88            case InstructionConstants.OP_INVOKEVIRTUAL:
89            case InstructionConstants.OP_INVOKESPECIAL:
90            case InstructionConstants.OP_INVOKESTATIC:
91            case InstructionConstants.OP_INVOKEINTERFACE:
92                // Get the name of the bridged method.
93                clazz.constantPoolEntryAccept(constantInstruction.constantIndex, this);
94
95                // Check if the name is different.
96                if (!method.getName(clazz).equals(bridgedMethodName))
97                {
98                    if (DEBUG)
99                    {
100                        System.out.println("BridgeMethodFixer: ["+clazz.getName()+"."+method.getName(clazz)+method.getDescriptor(clazz)+"] does not bridge to ["+bridgedMethodName+"]");
101                    }
102
103                    // Clear the bridge flag.
104                    ((ProgramMethod)method).u2accessFlags &= ~ClassConstants.INTERNAL_ACC_BRIDGE;
105                }
106                break;
107        }
108    }
109
110
111    // Implementations for ConstantVisitor.
112
113    public void visitAnyMethodrefConstant(Clazz clazz, RefConstant refConstant)
114    {
115        bridgedMethodName = refConstant.getName(clazz);
116    }
117}