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/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2019 Guardsquare NV
*
* 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.optimize.evaluation;
import proguard.classfile.*;
import proguard.classfile.attribute.*;
import proguard.classfile.attribute.visitor.*;
import proguard.classfile.constant.*;
import proguard.classfile.editor.*;
import proguard.classfile.instruction.*;
import proguard.classfile.instruction.visitor.InstructionVisitor;
import proguard.classfile.util.SimplifiedVisitor;
import proguard.classfile.visitor.*;
import proguard.optimize.info.SimpleEnumMarker;
import proguard.optimize.peephole.*;
/**
* This ClassVisitor simplifies the classes that it visits to simple enums.
*
* @see SimpleEnumMarker
* @see MemberReferenceFixer
* @author Eric Lafortune
*/
public class SimpleEnumClassSimplifier
extends SimplifiedVisitor
implements ClassVisitor,
AttributeVisitor,
InstructionVisitor
{
//*
private static final boolean DEBUG = false;
/*/
private static boolean DEBUG = System.getProperty("enum") != null;
//*/
private static final int ENUM_CLASS_NAME = InstructionSequenceReplacer.A;
private static final int ENUM_TYPE_NAME = InstructionSequenceReplacer.B;
private static final int ENUM_CONSTANT_NAME = InstructionSequenceReplacer.X;
private static final int ENUM_CONSTANT_ORDINAL = InstructionSequenceReplacer.Y;
private static final int ENUM_CONSTANT_FIELD_NAME = InstructionSequenceReplacer.Z;
private static final int STRING_ENUM_CONSTANT_NAME = 0;
private static final int METHOD_ENUM_INIT = 1;
private static final int FIELD_ENUM_CONSTANT = 2;
private static final int CLASS_ENUM = 3;
private static final int NAME_AND_TYPE_ENUM_INIT = 4;
private static final int NAME_AND_TYPE_ENUM_CONSTANT = 5;
private static final int UTF8_INIT = 6;
private static final int UTF8_STRING_I = 7;
private static final Constant[] CONSTANTS = new Constant[]
{
new StringConstant(ENUM_CONSTANT_NAME, null, null),
new MethodrefConstant(CLASS_ENUM, NAME_AND_TYPE_ENUM_INIT, null, null),
new FieldrefConstant( CLASS_ENUM, NAME_AND_TYPE_ENUM_CONSTANT, null, null),
new ClassConstant(ENUM_CLASS_NAME, null),
new NameAndTypeConstant(UTF8_INIT, UTF8_STRING_I),
new NameAndTypeConstant(ENUM_CONSTANT_FIELD_NAME, ENUM_TYPE_NAME),
new Utf8Constant(ClassConstants.METHOD_NAME_INIT),
new Utf8Constant(ClassConstants.METHOD_TYPE_INIT_ENUM),
};
private static final Instruction[][][] INSTRUCTION_SEQUENCES = new Instruction[][][]
{
{
// Replace new Enum("name", constant)
// by constant + 1.
{
new ConstantInstruction(InstructionConstants.OP_NEW, CLASS_ENUM),
new SimpleInstruction(InstructionConstants.OP_DUP),
new ConstantInstruction(InstructionConstants.OP_LDC, STRING_ENUM_CONSTANT_NAME),
new SimpleInstruction(InstructionConstants.OP_ICONST_0, ENUM_CONSTANT_ORDINAL),
new ConstantInstruction(InstructionConstants.OP_INVOKESPECIAL, METHOD_ENUM_INIT),
},
{
new SimpleInstruction(InstructionConstants.OP_SIPUSH, ENUM_CONSTANT_ORDINAL),
new SimpleInstruction(InstructionConstants.OP_ICONST_1),
new SimpleInstruction(InstructionConstants.OP_IADD),
}
},
{
// The name constants may have been encrypted.
// Replace (..., constant)
// by (..., 0); pop; constant + 1.
{
new SimpleInstruction(InstructionConstants.OP_ICONST_0, ENUM_CONSTANT_ORDINAL),
new ConstantInstruction(InstructionConstants.OP_INVOKESPECIAL, METHOD_ENUM_INIT),
},
{
new SimpleInstruction(InstructionConstants.OP_ICONST_0),
new ConstantInstruction(InstructionConstants.OP_INVOKESPECIAL, METHOD_ENUM_INIT),
new SimpleInstruction(InstructionConstants.OP_POP),
new SimpleInstruction(InstructionConstants.OP_SIPUSH, ENUM_CONSTANT_ORDINAL),
new SimpleInstruction(InstructionConstants.OP_ICONST_1),
new SimpleInstruction(InstructionConstants.OP_IADD),
}
},
};
private final CodeAttributeEditor codeAttributeEditor =
new CodeAttributeEditor(true, true);
private final InstructionSequencesReplacer instructionSequenceReplacer =
new InstructionSequencesReplacer(CONSTANTS,
INSTRUCTION_SEQUENCES,
null,
codeAttributeEditor);
private final MemberVisitor initializerSimplifier = new AllAttributeVisitor(this);
// Implementations for ClassVisitor.
public void visitProgramClass(ProgramClass programClass)
{
if (DEBUG)
{
System.out.println("SimpleEnumClassSimplifier: ["+programClass.getName()+"]");
}
// Unmark the class as an enum.
programClass.u2accessFlags &= ~ClassConstants.ACC_ENUM;
// Remove the valueOf method, if present.
Method valueOfMethod =
programClass.findMethod(ClassConstants.METHOD_NAME_VALUEOF, null);
if (valueOfMethod != null)
{
new ClassEditor(programClass).removeMethod(valueOfMethod);
}
// Simplify the static initializer.
programClass.methodAccept(ClassConstants.METHOD_NAME_CLINIT,
ClassConstants.METHOD_TYPE_CLINIT,
initializerSimplifier);
}
// Implementations for AttributeVisitor.
public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}
public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute)
{
// Set up the code attribute editor.
codeAttributeEditor.reset(codeAttribute.u4codeLength);
// Find the peephole changes.
codeAttribute.instructionsAccept(clazz, method, instructionSequenceReplacer);
// Apply the peephole changes.
codeAttributeEditor.visitCodeAttribute(clazz, method, codeAttribute);
}
}