1/* 2 * ProGuard -- shrinking, optimization, obfuscation, and preverification 3 * of Java bytecode. 4 * 5 * Copyright (c) 2002-2014 Eric Lafortune (eric@graphics.cornell.edu) 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License as published by the Free 9 * Software Foundation; either version 2 of the License, or (at your option) 10 * any later version. 11 * 12 * This program is distributed in the hope that it will be useful, but WITHOUT 13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 15 * more details. 16 * 17 * You should have received a copy of the GNU General Public License along 18 * with this program; if not, write to the Free Software Foundation, Inc., 19 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 */ 21package proguard.classfile.editor; 22 23import proguard.classfile.*; 24import proguard.classfile.attribute.*; 25import proguard.classfile.attribute.visitor.AttributeVisitor; 26import proguard.classfile.instruction.*; 27import proguard.classfile.instruction.visitor.InstructionVisitor; 28import proguard.classfile.util.*; 29 30/** 31 * This AttributeVisitor computes and updates the maximum local variable frame 32 * size of the code attributes that it visits. It also cleans up the local 33 * variable tables. 34 * 35 * @author Eric Lafortune 36 */ 37public class VariableSizeUpdater 38extends SimplifiedVisitor 39implements AttributeVisitor, 40 InstructionVisitor 41{ 42 //* 43 private static final boolean DEBUG = false; 44 /*/ 45 private static boolean DEBUG = true; 46 //*/ 47 48 49 private VariableCleaner variableCleaner = new VariableCleaner(); 50 51 52 // Implementations for AttributeVisitor. 53 54 public void visitAnyAttribute(Clazz clazz, Attribute attribute) {} 55 56 57 public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute) 58 { 59// DEBUG = 60// clazz.getName().equals("abc/Def") && 61// method.getName(clazz).equals("abc"); 62 63 // The minimum variable size is determined by the arguments. 64 codeAttribute.u2maxLocals = 65 ClassUtil.internalMethodParameterSize(method.getDescriptor(clazz), 66 method.getAccessFlags()); 67 68 if (DEBUG) 69 { 70 System.out.println("VariableSizeUpdater: "+clazz.getName()+"."+method.getName(clazz)+method.getDescriptor(clazz)); 71 System.out.println(" Max locals: "+codeAttribute.u2maxLocals+" <- parameters"); 72 } 73 74 // Go over all instructions. 75 codeAttribute.instructionsAccept(clazz, method, this); 76 77 // Remove the unused variables of the attributes. 78 variableCleaner.visitCodeAttribute(clazz, method, codeAttribute); 79 } 80 81 82 // Implementations for InstructionVisitor. 83 84 public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {} 85 86 87 public void visitVariableInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, VariableInstruction variableInstruction) 88 { 89 int variableSize = variableInstruction.variableIndex + 1; 90 if (variableInstruction.isCategory2()) 91 { 92 variableSize++; 93 } 94 95 if (codeAttribute.u2maxLocals < variableSize) 96 { 97 codeAttribute.u2maxLocals = variableSize; 98 99 if (DEBUG) 100 { 101 System.out.println(" Max locals: "+codeAttribute.u2maxLocals+" <- "+variableInstruction.toString(offset)); 102 } 103 } 104 } 105} 106