1b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato/* 2b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * ProGuard -- shrinking, optimization, obfuscation, and preverification 3b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * of Java bytecode. 4b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * 5b9cc48a43ed984587c939d02fba5316bf5c0df6eYing Wang * Copyright (c) 2002-2013 Eric Lafortune (eric@graphics.cornell.edu) 6b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * 7b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * This program is free software; you can redistribute it and/or modify it 8b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * under the terms of the GNU General Public License as published by the Free 9b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * Software Foundation; either version 2 of the License, or (at your option) 10b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * any later version. 11b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * 12b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * This program is distributed in the hope that it will be useful, but WITHOUT 13b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 14b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 15b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * more details. 16b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * 17b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * You should have received a copy of the GNU General Public License along 18b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * with this program; if not, write to the Free Software Foundation, Inc., 19b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato */ 21b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratopackage proguard.optimize; 22b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 23b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.*; 24b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.attribute.*; 25b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.attribute.visitor.AttributeVisitor; 26b9cc48a43ed984587c939d02fba5316bf5c0df6eYing Wangimport proguard.classfile.editor.VariableRemapper; 27b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.util.*; 28b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.visitor.MemberVisitor; 29b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.optimize.info.ParameterUsageMarker; 30b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 31b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato/** 32b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * This MemberVisitor removes unused parameters from the code of the methods 33b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * that it visits. 34b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * 35b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * @see ParameterUsageMarker 36b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * @see MethodStaticizer 37b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * @see MethodDescriptorShrinker 38b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * @author Eric Lafortune 39b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato */ 40b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratopublic class ParameterShrinker 41b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoextends SimplifiedVisitor 42b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimplements AttributeVisitor 43b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato{ 44b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato private static final boolean DEBUG = false; 45b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 46b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 47b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato private final MemberVisitor extraVariableMemberVisitor; 48b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 49b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato private final VariableRemapper variableRemapper = new VariableRemapper(); 50b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 51b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 52b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato /** 53b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * Creates a new ParameterShrinker. 54b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato */ 55b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato public ParameterShrinker() 56b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 57b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato this(null); 58b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 59b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 60b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 61b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato /** 62b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * Creates a new ParameterShrinker with an extra visitor. 63b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * @param extraVariableMemberVisitor an optional extra visitor for all 64b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * removed parameters. 65b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato */ 66b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato public ParameterShrinker(MemberVisitor extraVariableMemberVisitor) 67b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 68b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato this.extraVariableMemberVisitor = extraVariableMemberVisitor; 69b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 70b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 71b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 72b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Implementations for AttributeVisitor. 73b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 74b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato public void visitAnyAttribute(Clazz clazz, Attribute attribute) {} 75b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 76b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 77b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute) 78b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 79b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Get the original parameter size that was saved. 80b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int oldParameterSize = ParameterUsageMarker.getParameterSize(method); 81b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 82b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Compute the new parameter size from the shrunk descriptor. 83b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int newParameterSize = 84b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato ClassUtil.internalMethodParameterSize(method.getDescriptor(clazz), 85b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato method.getAccessFlags()); 86b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 87b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (oldParameterSize > newParameterSize) 88b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 89b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Get the total size of the local variable frame. 90b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int maxLocals = codeAttribute.u2maxLocals; 91b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 92b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (DEBUG) 93b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 94b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato System.out.println("ParameterShrinker: "+clazz.getName()+"."+method.getName(clazz)+method.getDescriptor(clazz)); 95b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato System.out.println(" Old parameter size = " + oldParameterSize); 96b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato System.out.println(" New parameter size = " + newParameterSize); 97b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato System.out.println(" Max locals = " + maxLocals); 98b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 99b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 100b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Create a variable map. 101b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int[] variableMap = new int[maxLocals]; 102b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 103b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Move unused parameters right after the parameter block. 104b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int usedParameterIndex = 0; 105b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int unusedParameterIndex = newParameterSize; 106b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato for (int parameterIndex = 0; parameterIndex < oldParameterSize; parameterIndex++) 107b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 108b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Is the variable required as a parameter? 109b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (ParameterUsageMarker.isParameterUsed(method, parameterIndex)) 110b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 111b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Keep the variable as a parameter. 112b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato variableMap[parameterIndex] = usedParameterIndex++; 113b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 114b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato else 115b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 116b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (DEBUG) 117b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 118b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato System.out.println(" Deleting parameter #"+parameterIndex); 119b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 120b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 121b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Shift the variable to the unused parameter block, 122b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // in case it is still used as a variable. 123b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato variableMap[parameterIndex] = unusedParameterIndex++; 124b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 125b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Visit the method, if required. 126b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (extraVariableMemberVisitor != null) 127b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 128b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato method.accept(clazz, extraVariableMemberVisitor); 129b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 130b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 131b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 132b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 133b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Fill out the remainder of the map. 134b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato for (int variableIndex = oldParameterSize; variableIndex < maxLocals; variableIndex++) 135b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 136b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato variableMap[variableIndex] = variableIndex; 137b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 138b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 139b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Set the map. 140b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato variableRemapper.setVariableMap(variableMap); 141b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 142b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Remap the variables. 143b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato variableRemapper.visitCodeAttribute(clazz, method, codeAttribute); 144b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 145b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 146b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato} 147