instructionsequencematcher.java

来自「proguard 一个java的混淆器」· Java 代码 · 共 625 行 · 第 1/2 页

/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification
 *             of Java bytecode.
 *
 * Copyright (c) 2002-2007 Eric Lafortune ([e-mail])
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.util;

import proguard.classfile.*;
import proguard.classfile.attribute.CodeAttribute;
import proguard.classfile.constant.*;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.classfile.instruction.*;
import proguard.classfile.instruction.visitor.InstructionVisitor;

/**
 * This InstructionVisitor checks whether a given pattern instruction sequence
 * occurs in the instructions that are visited. The arguments of the
 * instruction sequence can be wildcards that are matched.
 *
 * @author Eric Lafortune
 */
public class InstructionSequenceMatcher
extends      SimplifiedVisitor
implements   InstructionVisitor,
             ConstantVisitor
{
    /*
    private static       boolean DEBUG      = false;
    public  static       boolean DEBUG_MORE = false;
    /*/
    private static final boolean DEBUG      = false;
    private static final boolean DEBUG_MORE = false;
    //*/

    public static final int X = 0x40000000;
    public static final int Y = 0x40000001;
    public static final int Z = 0x40000002;

    public static final int A = 0x40000003;
    public static final int B = 0x40000004;
    public static final int C = 0x40000005;
    public static final int D = 0x40000006;


    private final Constant[]    patternConstants;
    private final Instruction[] patternInstructions;

    private boolean matching;
    private int   patternInstructionIndex;
    private final int[] matchedInstructionOffsets;
    private int   matchedArgumentFlags;
    private final int[] matchedArguments = new int[7];
    private int   matchedConstantFlags;
    private final int[] matchedConstantIndices;

    // Fields acting as a parameter and a return value for visitor methods.
    private Constant patternConstant;
    private boolean  matchingConstant;


    /**
     * Creates a new InstructionSequenceMatcher.
     * @param patternConstants        any constants referenced by the pattern
     *                                instruction.
     * @param patternInstructions     the pattern instruction sequence.
     */
    public InstructionSequenceMatcher(Constant[]    patternConstants,
                                      Instruction[] patternInstructions)
    {
        this.patternConstants    = patternConstants;
        this.patternInstructions = patternInstructions;

        matchedInstructionOffsets = new int[patternInstructions.length];
        matchedConstantIndices    = new int[patternConstants.length];
    }


    /**
     * Starts matching from the first instruction again next time.
     */
    public void reset()
    {
        patternInstructionIndex = 0;
        matchedArgumentFlags    = 0;
        matchedConstantFlags    = 0;
    }


    public boolean isMatching()
    {
        return matching;
    }


    public int instructionCount()
    {
        return patternInstructions.length;
    }


    public int matchedInstructionOffset(int index)
    {
        return matchedInstructionOffsets[index];
    }


    public int matchedArgument(int argument)
    {
        int argumentIndex = argument - X;
        return argumentIndex < 0 ?
            argument :
            matchedArguments[argumentIndex];
    }


    public int[] matchedArguments(int[] arguments)
    {
        int[] matchedArguments = new int[arguments.length];

        for (int index = 0; index < arguments.length; index++)
        {
            matchedArguments[index] = matchedArgument(arguments[index]);
        }

        return matchedArguments;
    }


    public int matchedConstantIndex(int constantIndex)
    {
        int argumentIndex = constantIndex - X;
        return argumentIndex < 0 ?
            matchedConstantIndices[constantIndex] :
            matchedArguments[argumentIndex];
    }


    public int matchedBranchOffset(int offset, int branchOffset)
    {
        int argumentIndex = branchOffset - X;
        return argumentIndex < 0 ?
            branchOffset :
            matchedArguments[argumentIndex] - offset;
    }


    public int[] matchedJumpOffsets(int offset, int[] jumpOffsets)
    {
        int[] matchedJumpOffsets = new int[jumpOffsets.length];

        for (int index = 0; index < jumpOffsets.length; index++)
        {
            matchedJumpOffsets[index] = matchedBranchOffset(offset,
                                                            jumpOffsets[index]);
        }

        return matchedJumpOffsets;
    }


    // Implementations for InstructionVisitor.

    public void visitSimpleInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, SimpleInstruction simpleInstruction)
    {
        Instruction patternInstruction = patternInstructions[patternInstructionIndex];

        // Check if the instruction matches the next instruction in the sequence.
        boolean condition =
            matchingOpcodes(simpleInstruction, patternInstruction) &&
            matchingArguments(simpleInstruction.constant,
                              ((SimpleInstruction)patternInstruction).constant);

        // Check if the instruction sequence is matching now.
        checkMatch(condition,
                   clazz,
                   method,
                   codeAttribute,
                   offset,
                   simpleInstruction);
    }


    public void visitVariableInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, VariableInstruction variableInstruction)
    {
        Instruction patternInstruction = patternInstructions[patternInstructionIndex];

        // Check if the instruction matches the next instruction in the sequence.
        boolean condition =
            matchingOpcodes(variableInstruction, patternInstruction) &&
            matchingArguments(variableInstruction.variableIndex,
                              ((VariableInstruction)patternInstruction).variableIndex) &&
            matchingArguments(variableInstruction.constant,
                              ((VariableInstruction)patternInstruction).constant);

        // Check if the instruction sequence is matching now.
        checkMatch(condition,
                   clazz,
                   method,
                   codeAttribute,
                   offset,
                   variableInstruction);
    }


    public void visitConstantInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, ConstantInstruction constantInstruction)
    {
        Instruction patternInstruction = patternInstructions[patternInstructionIndex];

        // Check if the instruction matches the next instruction in the sequence.
        boolean condition =
            matchingOpcodes(constantInstruction, patternInstruction) &&
            matchingConstantIndices(clazz,
                                    constantInstruction.constantIndex,
                                    ((ConstantInstruction)patternInstruction).constantIndex) &&
            matchingArguments(constantInstruction.constant,
                              ((ConstantInstruction)patternInstruction).constant);

        // Check if the instruction sequence is matching now.
        checkMatch(condition,
                   clazz,
                   method,
                   codeAttribute,
                   offset,
                   constantInstruction);
    }


    public void visitBranchInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, BranchInstruction branchInstruction)
    {
        Instruction patternInstruction = patternInstructions[patternInstructionIndex];

        // Check if the instruction matches the next instruction in the from
        // sequence.
        boolean condition =
            matchingOpcodes(branchInstruction, patternInstruction) &&
            matchingBranchOffsets(offset,
                                  branchInstruction.branchOffset,
                                  ((BranchInstruction)patternInstruction).branchOffset);

        // Check if the instruction sequence is matching now.
        checkMatch(condition,
                   clazz,
                   method,
                   codeAttribute,
                   offset,
                   branchInstruction);
    }


    public void visitTableSwitchInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, TableSwitchInstruction tableSwitchInstruction)
    {
        Instruction patternInstruction = patternInstructions[patternInstructionIndex];

        // Check if the instruction matches the next instruction in the sequence.
        boolean condition =
            matchingOpcodes(tableSwitchInstruction, patternInstruction) &&
            matchingBranchOffsets(offset,
                                  tableSwitchInstruction.defaultOffset,
                                  ((TableSwitchInstruction)patternInstruction).defaultOffset) &&
            matchingArguments(tableSwitchInstruction.lowCase,
                              ((TableSwitchInstruction)patternInstruction).lowCase)  &&
            matchingArguments(tableSwitchInstruction.highCase,
                              ((TableSwitchInstruction)patternInstruction).highCase) &&
            matchingJumpOffsets(offset,
                                tableSwitchInstruction.jumpOffsets,
                                ((TableSwitchInstruction)patternInstruction).jumpOffsets);

        // Check if the instruction sequence is matching now.
        checkMatch(condition,
                   clazz,
                   method,
                   codeAttribute,
                   offset,
                   tableSwitchInstruction);
    }


    public void visitLookUpSwitchInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, LookUpSwitchInstruction lookUpSwitchInstruction)
    {
        Instruction patternInstruction = patternInstructions[patternInstructionIndex];

        // Check if the instruction matches the next instruction in the sequence.
        boolean condition =
            matchingOpcodes(lookUpSwitchInstruction, patternInstruction) &&
            matchingBranchOffsets(offset,
                                  lookUpSwitchInstruction.defaultOffset,
                                  ((LookUpSwitchInstruction)patternInstruction).defaultOffset) &&
            matchingArguments(lookUpSwitchInstruction.cases,
                              ((LookUpSwitchInstruction)patternInstruction).cases) &&
            matchingJumpOffsets(offset,
                                lookUpSwitchInstruction.jumpOffsets,
                                ((LookUpSwitchInstruction)patternInstruction).jumpOffsets);

        // Check if the instruction sequence is matching now.
        checkMatch(condition,
                   clazz,
                   method,
                   codeAttribute,