proguard.classfile.util.PrimitiveArrayConstantReplacer Maven / Gradle / Ivy

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ProGuardCORE is a free library to read, analyze, modify, and write Java class files.
There is a newer version: 9.1.7
/*
 * ProGuardCORE -- library to process Java bytecode.
 *
 * Copyright (c) 2002-2020 Guardsquare NV
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package proguard.classfile.util;

import proguard.classfile.*;
import proguard.classfile.attribute.*;
import proguard.classfile.attribute.visitor.*;
import proguard.classfile.constant.*;
import proguard.classfile.constant.visitor.*;
import proguard.classfile.editor.*;
import proguard.classfile.instruction.*;
import proguard.classfile.instruction.visitor.InstructionVisitor;
import proguard.classfile.visitor.ClassVisitor;

/**
 * This {@link ClassVisitor} replaces all instances of {@link PrimitiveArrayConstant}
 * by Java bytecode compliant array store instructions.
 *
 * @see ArrayInitializationReplacer
 * @author Thomas Neidhart
 */
public class PrimitiveArrayConstantReplacer
implements   ClassVisitor,
             AttributeVisitor,
             InstructionVisitor,
             ConstantVisitor,
             PrimitiveArrayConstantElementVisitor
{
    private final CodeAttributeEditor  codeAttributeEditor  = new CodeAttributeEditor();
    private final ConstantPoolShrinker constantPoolShrinker = new ConstantPoolShrinker();

    // Fields acting as parameters and return values.

    private boolean                        classModified;
    private InstructionSequenceBuilder builder;


    // Implementations for ClassVisitor.

    @Override
    public void visitAnyClass(Clazz clazz) { }


    @Override
    public void visitProgramClass(ProgramClass programClass)
    {
        ConstantCounter counter = new ConstantCounter();
        programClass.constantPoolEntriesAccept(
            new ConstantTagFilter(Constant.PRIMITIVE_ARRAY,
            counter));

        // Replace PrimitiveArray constants if the class has any.
        if (counter.getCount() > 0)
        {
            classModified = false;

            programClass.methodsAccept(new AllAttributeVisitor(this));

            if (classModified)
            {
                // Remove the now unused PrimitiveArray constants.
                programClass.accept(constantPoolShrinker);
            }
        }
    }


    // Implementations for AttributeVisitor.

    public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}


    public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute)
    {
        codeAttributeEditor.reset(codeAttribute.u4codeLength);

        codeAttribute.instructionsAccept(clazz, method, this);

        if (codeAttributeEditor.isModified())
        {
            codeAttributeEditor.visitCodeAttribute(clazz, method, codeAttribute);

            classModified = true;
        }
    }


    // Implementations for InstructionVisitor.

    public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {}


    public void visitConstantInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, ConstantInstruction constantInstruction)
    {
        builder = null;

        clazz.constantPoolEntryAccept(constantInstruction.constantIndex, this);

        if (builder != null)
        {
            codeAttributeEditor.replaceInstruction(offset, builder.instructions());

            classModified = true;
        }
    }


    // Implementations for ConstantVisitor.

    public void visitAnyConstant(Clazz clazz, Constant constant) {}


    public void visitPrimitiveArrayConstant(Clazz clazz, PrimitiveArrayConstant primitiveArrayConstant)
    {
        char primitiveType = primitiveArrayConstant.getPrimitiveType();
        int  arrayLength   = primitiveArrayConstant.getLength();

        // Start composing a new array initialization sequence.
        builder = new InstructionSequenceBuilder((ProgramClass) clazz);

        // Push the primitive array length.
        builder.pushInt(arrayLength);

        // Create the primitive array.
        builder.newarray(InstructionUtil.arrayTypeFromInternalType(primitiveType));

        // Fill out the primitive array elements.
        primitiveArrayConstant.primitiveArrayElementsAccept(clazz, this);
    }


    // Implementations for PrimitiveArrayConstantElementVisitor.

    public void visitBooleanArrayConstantElement(Clazz clazz, PrimitiveArrayConstant primitiveArrayConstant, int index, boolean value)
    {
        builder.dup()
               .pushInt(index)
               .iconst(value ? 1 : 0)
               .bastore();
    }


    public void visitByteArrayConstantElement(Clazz clazz, PrimitiveArrayConstant primitiveArrayConstant, int index, byte value)
    {
        builder.dup()
               .pushInt(index)
               .pushInt(value)
               .bastore();
    }


    public void visitCharArrayConstantElement(Clazz clazz, PrimitiveArrayConstant primitiveArrayConstant, int index, char value)
    {
        builder.dup()
               .pushInt(index)
               .pushInt(value)
               .castore();
    }


    public void visitShortArrayConstantElement(Clazz clazz, PrimitiveArrayConstant primitiveArrayConstant, int index, short value)
    {
        builder.dup()
               .pushInt(index)
               .pushInt(value)
               .sastore();
    }


    public void visitIntArrayConstantElement(Clazz clazz, PrimitiveArrayConstant primitiveArrayConstant, int index, int value)
    {
        builder.dup()
               .pushInt(index)
               .pushInt(value)
               .iastore();
    }


    public void visitFloatArrayConstantElement(Clazz clazz, PrimitiveArrayConstant primitiveArrayConstant, int index, float value)
    {
        builder.dup()
               .pushInt(index)
               .pushFloat(value)
               .fastore();
    }


    public void visitLongArrayConstantElement(Clazz clazz, PrimitiveArrayConstant primitiveArrayConstant, int index, long value)
    {
        builder.dup()
               .pushInt(index)
               .pushLong(value)
               .lastore();
    }


    public void visitDoubleArrayConstantElement(Clazz clazz, PrimitiveArrayConstant primitiveArrayConstant, int index, double value)
    {
        builder.dup()
               .pushInt(index)
               .pushDouble(value)
               .dastore();
    }
}