| /* |
| * 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.classfile.editor; |
| |
| import proguard.classfile.*; |
| import proguard.classfile.attribute.*; |
| import proguard.classfile.attribute.visitor.*; |
| import proguard.classfile.instruction.*; |
| import proguard.classfile.instruction.visitor.InstructionVisitor; |
| import proguard.classfile.util.SimplifiedVisitor; |
| |
| /** |
| * This AttributeVisitor remaps variable indexes in all attributes that it |
| * visits, based on a given index map. |
| * |
| * @author Eric Lafortune |
| */ |
| public class VariableRemapper |
| extends SimplifiedVisitor |
| implements AttributeVisitor, |
| InstructionVisitor, |
| LocalVariableInfoVisitor, |
| LocalVariableTypeInfoVisitor |
| { |
| private final CodeAttributeEditor codeAttributeEditor = new CodeAttributeEditor(); |
| |
| private int[] variableMap; |
| |
| |
| /** |
| * Sets the given mapping of old variable indexes to their new indexes. |
| * Variables that should disappear can be mapped to -1. |
| */ |
| public void setVariableMap(int[] variableMap) |
| { |
| this.variableMap = variableMap; |
| } |
| |
| |
| // Implementations for AttributeVisitor. |
| |
| public void visitAnyAttribute(Clazz clazz, Attribute attribute) {} |
| |
| |
| public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute) |
| { |
| // Initially, the code attribute editor doesn't contain any changes. |
| codeAttributeEditor.reset(codeAttribute.u4codeLength); |
| |
| // Remap the variables of the instructions. |
| codeAttribute.instructionsAccept(clazz, method, this); |
| |
| // Apply the code atribute editor. |
| codeAttributeEditor.visitCodeAttribute(clazz, method, codeAttribute); |
| |
| // Remap the variables of the attributes. |
| codeAttribute.attributesAccept(clazz, method, this); |
| } |
| |
| |
| public void visitLocalVariableTableAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTableAttribute localVariableTableAttribute) |
| { |
| // Remap the variable references of the local variables. |
| localVariableTableAttribute.localVariablesAccept(clazz, method, codeAttribute, this); |
| |
| // Remove local variables that haven't been mapped. |
| localVariableTableAttribute.u2localVariableTableLength = |
| removeEmptyLocalVariables(localVariableTableAttribute.localVariableTable, |
| localVariableTableAttribute.u2localVariableTableLength); |
| } |
| |
| |
| public void visitLocalVariableTypeTableAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTypeTableAttribute localVariableTypeTableAttribute) |
| { |
| // Remap the variable references of the local variables. |
| localVariableTypeTableAttribute.localVariablesAccept(clazz, method, codeAttribute, this); |
| |
| // Remove local variables that haven't been mapped. |
| localVariableTypeTableAttribute.u2localVariableTypeTableLength = |
| removeEmptyLocalVariableTypes(localVariableTypeTableAttribute.localVariableTypeTable, |
| localVariableTypeTableAttribute.u2localVariableTypeTableLength); |
| } |
| |
| |
| // Implementations for LocalVariableInfoVisitor. |
| |
| public void visitLocalVariableInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableInfo localVariableInfo) |
| { |
| localVariableInfo.u2index = |
| remapVariable(localVariableInfo.u2index); |
| } |
| |
| |
| // Implementations for LocalVariableTypeInfoVisitor. |
| |
| public void visitLocalVariableTypeInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTypeInfo localVariableTypeInfo) |
| { |
| localVariableTypeInfo.u2index = |
| remapVariable(localVariableTypeInfo.u2index); |
| } |
| |
| |
| // Implementations for InstructionVisitor. |
| |
| public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {} |
| |
| |
| public void visitVariableInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, VariableInstruction variableInstruction) |
| { |
| // Is the new variable index different from the original one? |
| int oldVariableIndex = variableInstruction.variableIndex; |
| int newVariableIndex = remapVariable(oldVariableIndex); |
| if (newVariableIndex != oldVariableIndex) |
| { |
| // Replace the instruction. |
| Instruction replacementInstruction = |
| new VariableInstruction(variableInstruction.opcode, |
| newVariableIndex, |
| variableInstruction.constant).shrink(); |
| |
| codeAttributeEditor.replaceInstruction(offset, replacementInstruction); |
| } |
| } |
| |
| |
| // Small utility methods. |
| |
| /** |
| * Returns the new variable index of the given variable. |
| */ |
| private int remapVariable(int variableIndex) |
| { |
| return variableMap[variableIndex]; |
| } |
| |
| |
| /** |
| * Returns the given list of local variables, without the ones that have |
| * been removed. |
| */ |
| private int removeEmptyLocalVariables(LocalVariableInfo[] localVariableInfos, |
| int localVariableInfoCount) |
| { |
| // Overwrite all empty local variable entries. |
| int newIndex = 0; |
| for (int index = 0; index < localVariableInfoCount; index++) |
| { |
| LocalVariableInfo localVariableInfo = localVariableInfos[index]; |
| if (localVariableInfo.u2index >= 0) |
| { |
| localVariableInfos[newIndex++] = localVariableInfo; |
| } |
| } |
| |
| return newIndex; |
| } |
| |
| |
| /** |
| * Returns the given list of local variable types, without the ones that |
| * have been removed. |
| */ |
| private int removeEmptyLocalVariableTypes(LocalVariableTypeInfo[] localVariableTypeInfos, |
| int localVariableTypeInfoCount) |
| { |
| // Overwrite all empty local variable type entries. |
| int newIndex = 0; |
| for (int index = 0; index < localVariableTypeInfoCount; index++) |
| { |
| LocalVariableTypeInfo localVariableTypeInfo = localVariableTypeInfos[index]; |
| if (localVariableTypeInfo.u2index >= 0) |
| { |
| localVariableTypeInfos[newIndex++] = localVariableTypeInfo; |
| } |
| } |
| |
| return newIndex; |
| } |
| } |