| /* |
| * 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.info; |
| |
| import proguard.classfile.*; |
| import proguard.classfile.attribute.CodeAttribute; |
| import proguard.classfile.constant.*; |
| import proguard.classfile.constant.visitor.ConstantVisitor; |
| import proguard.classfile.instruction.*; |
| import proguard.classfile.instruction.visitor.InstructionVisitor; |
| import proguard.classfile.util.SimplifiedVisitor; |
| import proguard.classfile.visitor.MemberVisitor; |
| |
| /** |
| * This InstructionVisitor marks all fields that are write-only. |
| * |
| * @author Eric Lafortune |
| */ |
| public class ReadWriteFieldMarker |
| extends SimplifiedVisitor |
| implements InstructionVisitor, |
| ConstantVisitor, |
| MemberVisitor |
| { |
| // Parameters for the visitor methods. |
| private boolean reading = true; |
| private boolean writing = 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) |
| { |
| byte opcode = constantInstruction.opcode; |
| |
| // Check for instructions that involve fields. |
| switch (opcode) |
| { |
| case InstructionConstants.OP_LDC: |
| case InstructionConstants.OP_LDC_W: |
| // Mark the field, if any, as being read from and written to. |
| reading = true; |
| writing = true; |
| clazz.constantPoolEntryAccept(constantInstruction.constantIndex, this); |
| break; |
| |
| case InstructionConstants.OP_GETSTATIC: |
| case InstructionConstants.OP_GETFIELD: |
| // Mark the field as being read from. |
| reading = true; |
| writing = false; |
| clazz.constantPoolEntryAccept(constantInstruction.constantIndex, this); |
| break; |
| |
| case InstructionConstants.OP_PUTSTATIC: |
| case InstructionConstants.OP_PUTFIELD: |
| // Mark the field as being written to. |
| reading = false; |
| writing = true; |
| clazz.constantPoolEntryAccept(constantInstruction.constantIndex, this); |
| break; |
| } |
| } |
| |
| |
| // Implementations for ConstantVisitor. |
| |
| public void visitAnyConstant(Clazz clazz, Constant constant) {} |
| |
| |
| public void visitStringConstant(Clazz clazz, StringConstant stringConstant) |
| { |
| // Mark the referenced field, if any. |
| stringConstant.referencedMemberAccept(this); |
| } |
| |
| |
| public void visitFieldrefConstant(Clazz clazz, FieldrefConstant fieldrefConstant) |
| { |
| // Mark the referenced field. |
| fieldrefConstant.referencedMemberAccept(this); |
| } |
| |
| |
| // Implementations for MemberVisitor. |
| |
| public void visitAnyMember(Clazz Clazz, Member member) {} |
| |
| |
| public void visitProgramField(ProgramClass programClass, ProgramField programField) |
| { |
| // Mark the field if it is being read from. |
| if (reading) |
| { |
| markAsRead(programField); |
| } |
| |
| // Mark the field if it is being written to. |
| if (writing) |
| { |
| markAsWritten(programField); |
| } |
| } |
| |
| |
| // Small utility methods. |
| |
| private static void markAsRead(Field field) |
| { |
| FieldOptimizationInfo info = FieldOptimizationInfo.getFieldOptimizationInfo(field); |
| if (info != null) |
| { |
| info.setRead(); |
| } |
| } |
| |
| |
| public static boolean isRead(Field field) |
| { |
| FieldOptimizationInfo info = FieldOptimizationInfo.getFieldOptimizationInfo(field); |
| return info == null || |
| info.isRead(); |
| } |
| |
| |
| private static void markAsWritten(Field field) |
| { |
| FieldOptimizationInfo info = FieldOptimizationInfo.getFieldOptimizationInfo(field); |
| if (info != null) |
| { |
| info.setWritten(); |
| } |
| } |
| |
| |
| public static boolean isWritten(Field field) |
| { |
| FieldOptimizationInfo info = FieldOptimizationInfo.getFieldOptimizationInfo(field); |
| return info == null || |
| info.isWritten(); |
| } |
| } |