proguard.optimize.peephole.PeepholeOptimizer Maven / Gradle / Ivy
/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2018 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.peephole;
import proguard.classfile.*;
import proguard.classfile.attribute.*;
import proguard.classfile.attribute.visitor.AttributeVisitor;
import proguard.classfile.editor.CodeAttributeEditor;
import proguard.classfile.instruction.visitor.InstructionVisitor;
import proguard.classfile.util.SimplifiedVisitor;
/**
* This AttributeVisitor sets up and applies the peephole optimizations of its
* instruction visitor. The instruction visitor should be using the same
* (optional) branch target finder and code attribute editor.
*
* @author Eric Lafortune
*/
public class PeepholeOptimizer
extends SimplifiedVisitor
implements AttributeVisitor
{
private final BranchTargetFinder branchTargetFinder;
private final CodeAttributeEditor codeAttributeEditor;
private final InstructionVisitor instructionVisitor;
/**
* Creates a new PeepholeOptimizer.
* @param codeAttributeEditor the code attribute editor that will be reset
* and then executed.
* @param instructionVisitor the instruction visitor that performs
* peephole optimizations using the above code
* attribute editor.
*/
public PeepholeOptimizer(CodeAttributeEditor codeAttributeEditor,
InstructionVisitor instructionVisitor)
{
this(null, codeAttributeEditor, instructionVisitor);
}
/**
* Creates a new PeepholeOptimizer.
* @param branchTargetFinder branch target finder that will be initialized
* to indicate branch targets in the visited code.
* @param codeAttributeEditor the code attribute editor that will be reset
* and then executed.
* @param instructionVisitor the instruction visitor that performs
* peephole optimizations using the above code
* attribute editor.
*/
public PeepholeOptimizer(BranchTargetFinder branchTargetFinder,
CodeAttributeEditor codeAttributeEditor,
InstructionVisitor instructionVisitor)
{
this.branchTargetFinder = branchTargetFinder;
this.codeAttributeEditor = codeAttributeEditor;
this.instructionVisitor = instructionVisitor;
}
// Implementations for AttributeVisitor.
public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}
public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute)
{
if (branchTargetFinder != null)
{
// Set up the branch target finder.
branchTargetFinder.visitCodeAttribute(clazz, method, codeAttribute);
}
// Set up the code attribute editor.
codeAttributeEditor.reset(codeAttribute.u4codeLength);
// Find the peephole optimizations.
codeAttribute.instructionsAccept(clazz, method, instructionVisitor);
// Apply the peephole optimizations.
codeAttributeEditor.visitCodeAttribute(clazz, method, codeAttribute);
}
}
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