instructionsequencematcher.java

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

                   offset,
                   lookUpSwitchInstruction);
    }


    // Implementations for ConstantVisitor.

    public void visitIntegerConstant(Clazz clazz, IntegerConstant integerConstant)
    {
        IntegerConstant integerPatternConstant = (IntegerConstant)patternConstant;

        // Compare the integer values.
        matchingConstant = integerConstant.getValue() ==
                           integerPatternConstant.getValue();
    }


    public void visitLongConstant(Clazz clazz, LongConstant longConstant)
    {
        LongConstant longPatternConstant = (LongConstant)patternConstant;

        // Compare the long values.
        matchingConstant = longConstant.getValue() ==
                           longPatternConstant.getValue();
    }


    public void visitFloatConstant(Clazz clazz, FloatConstant floatConstant)
    {
        FloatConstant floatPatternConstant = (FloatConstant)patternConstant;

        // Compare the float values.
        matchingConstant = floatConstant.getValue() ==
                           floatPatternConstant.getValue();
    }


    public void visitDoubleConstant(Clazz clazz, DoubleConstant doubleConstant)
    {
        DoubleConstant doublePatternConstant = (DoubleConstant)patternConstant;

        // Compare the double values.
        matchingConstant = doubleConstant.getValue() ==
                           doublePatternConstant.getValue();
    }


    public void visitStringConstant(Clazz clazz, StringConstant stringConstant)
    {
        StringConstant stringPatternConstant = (StringConstant)patternConstant;

        // Check the UTF-8 constant.
        matchingConstant =
            matchingConstantIndices(clazz,
                                    stringConstant.u2stringIndex,
                                    stringPatternConstant.u2stringIndex);
    }


    public void visitUtf8Constant(Clazz clazz, Utf8Constant utf8Constant)
    {
        Utf8Constant utf8PatternConstant = (Utf8Constant)patternConstant;

        // Compare the actual strings.
        matchingConstant = utf8Constant.getString().equals(
                           utf8PatternConstant.getString());
    }


    public void visitAnyRefConstant(Clazz clazz, RefConstant refConstant)
    {
        RefConstant refPatternConstant = (RefConstant)patternConstant;

        // Check the class and the name and type.
        matchingConstant =
            matchingConstantIndices(clazz,
                                    refConstant.getClassIndex(),
                                    refPatternConstant.getClassIndex()) &&
            matchingConstantIndices(clazz,
                                    refConstant.getNameAndTypeIndex(),
                                    refPatternConstant.getNameAndTypeIndex());
    }


    public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
    {
        ClassConstant classPatternConstant = (ClassConstant)patternConstant;

        // Check the class name.
        matchingConstant =
            matchingConstantIndices(clazz,
                                    classConstant.u2nameIndex,
                                    classPatternConstant.u2nameIndex);
    }


    public void visitNameAndTypeConstant(Clazz clazz, NameAndTypeConstant nameAndTypeConstant)
    {
        NameAndTypeConstant typePatternConstant = (NameAndTypeConstant)patternConstant;

        // Check the name and the descriptor.
        matchingConstant =
            matchingConstantIndices(clazz,
                                    nameAndTypeConstant.u2nameIndex,
                                    typePatternConstant.u2nameIndex) &&
            matchingConstantIndices(clazz,
                                    nameAndTypeConstant.u2descriptorIndex,
                                    typePatternConstant.u2descriptorIndex);
    }


    // Small utility methods.

    private boolean matchingOpcodes(Instruction instruction1,
                                    Instruction instruction2)
    {
        // Check the opcode.
        return instruction1.opcode            == instruction2.opcode ||
               instruction1.canonicalOpcode() == instruction2.opcode;
    }


    private boolean matchingArguments(int argument1,
                                      int argument2)
    {
        int argumentIndex = argument2 - X;
        if (argumentIndex < 0)
        {
            // Check the literal argument.
            return argument1 == argument2;
        }
        else if ((matchedArgumentFlags & (1 << argumentIndex)) == 0)
        {
            // Store a wildcard argument.
            matchedArguments[argumentIndex] = argument1;
            matchedArgumentFlags |= 1 << argumentIndex;

            return true;
        }
        else
        {
            // Check the previously stored wildcard argument.
            return matchedArguments[argumentIndex] == argument1;
        }
    }


    private boolean matchingArguments(int[] arguments1,
                                      int[] arguments2)
    {
        if (arguments1.length != arguments2.length)
        {
            return false;
        }

        for (int index = 0; index < arguments1.length; index++)
        {
            if (!matchingArguments(arguments1[index], arguments2[index]))
            {
                return false;
            }
        }

        return true;
    }


    private boolean matchingConstantIndices(Clazz clazz,
                                            int   constantIndex1,
                                            int   constantIndex2)
    {
        if (constantIndex2 >= X)
        {
            // Check the constant index.
            return matchingArguments(constantIndex1, constantIndex2);
        }
        else if ((matchedConstantFlags & (1 << constantIndex2)) == 0)
        {
            // Check the actual constant.
            matchingConstant = false;
            patternConstant  = patternConstants[constantIndex2];

            if (clazz.getTag(constantIndex1) == patternConstant.getTag())
            {
                clazz.constantPoolEntryAccept(constantIndex1, this);

                if (matchingConstant)
                {
                    // Store the constant index.
                    matchedConstantIndices[constantIndex2] = constantIndex1;
                    matchedConstantFlags |= 1 << constantIndex2;
                }
            }

            return matchingConstant;
        }
        else
        {
            // Check a previously stored constant index.
            return matchedConstantIndices[constantIndex2] == constantIndex1;
        }
    }


    private boolean matchingBranchOffsets(int offset,
                                          int branchOffset1,
                                          int branchOffset2)
    {
        int argumentIndex = branchOffset2 - X;
        if (argumentIndex < 0)
        {
            // Check the literal argument.
            return branchOffset1 == branchOffset2;
        }
        else if ((matchedArgumentFlags & (1 << argumentIndex)) == 0)
        {
            // Store a wildcard argument.
            matchedArguments[argumentIndex] = offset + branchOffset1;
            matchedArgumentFlags |= 1 << argumentIndex;

            return true;
        }
        else
        {
            // Check the previously stored wildcard argument.
            return matchedArguments[argumentIndex] == offset + branchOffset1;
        }
    }


    private boolean matchingJumpOffsets(int   offset,
                                        int[] jumpOffsets1,
                                        int[] jumpOffsets2)
    {
        if (jumpOffsets1.length != jumpOffsets2.length)
        {
            return false;
        }

        for (int index = 0; index < jumpOffsets1.length; index++)
        {
            if (!matchingBranchOffsets(offset,
                                       jumpOffsets1[index],
                                       jumpOffsets2[index]))
            {
                return false;
            }
        }

        return true;
    }


    private void checkMatch(boolean       condition,
                            Clazz         clazz,
                            Method        method,
                            CodeAttribute codeAttribute,
                            int           offset,
                            Instruction   instruction)
    {
        if (DEBUG_MORE)
        {
            System.out.println("InstructionSequenceMatcher: ["+clazz.getName()+"."+method.getName(clazz)+method.getDescriptor(clazz)+"]: "+patternInstructions[patternInstructionIndex].toString(patternInstructionIndex)+(condition?"\t== ":"\t   ")+instruction.toString(offset));
        }

        // Did the instruction match?
        if (condition)
        {
            // Remember the offset of the matching instruction.
            matchedInstructionOffsets[patternInstructionIndex] = offset;

            // Try to match the next instruction next time.
            patternInstructionIndex++;

            // Did we match all instructions in the sequence?
            matching = patternInstructionIndex == patternInstructions.length;

            if (matching)
            {
                if (DEBUG)
                {
                    System.out.println("InstructionSequenceMatcher: ["+clazz.getName()+"."+method.getName(clazz)+method.getDescriptor(clazz)+"]");
                    for (int index = 0; index < patternInstructionIndex; index++)
                    {
                        System.out.println("    "+InstructionFactory.create(codeAttribute.code, matchedInstructionOffsets[index]).toString(matchedInstructionOffsets[index]));
                    }
                }

                // Start matching from the first instruction again next time.
                reset();
            }
        }
        else
        {
            // The instruction didn't match.
            matching = false;

            // Is this a failed second instruction?
            boolean retry = patternInstructionIndex == 1;

            // Start matching from the first instruction next time.
            reset();

            // Retry a failed second instruction as a first instruction.
            if (retry)
            {
                instruction.accept(clazz, method, codeAttribute, offset, this);
            }
        }
    }
}