| /* |
| * ProGuard -- shrinking, optimization, obfuscation, and preverification |
| * of Java bytecode. |
| * |
| * Copyright (c) 2002-2009 Eric Lafortune (eric@graphics.cornell.edu) |
| * |
| * 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); |
| } |
| } |