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

Go to download
Show more of this group Show more artifacts with this name
Show all versions of proguard-core Show documentation
ProGuardCORE is a free library to read, analyze, modify, and write Java class files.
There is a newer version: 9.1.6
/*
 * 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();
  }
}