1b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato/* 2b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * ProGuard -- shrinking, optimization, obfuscation, and preverification 3b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * of Java bytecode. 4b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * 52270795fbe0b277bfd49f40950ecaa78583175ccBrian Carlstrom * Copyright (c) 2002-2014 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.info; 22b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 23b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.*; 24b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.attribute.CodeAttribute; 25b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.instruction.*; 26b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.instruction.visitor.InstructionVisitor; 27b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.util.SimplifiedVisitor; 28b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 29b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato/** 30b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * This InstructionVisitor marks all methods that branch backward in any of the 31b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * instructions that it visits. 32b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * 33b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * @author Eric Lafortune 34b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato */ 35b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratopublic class BackwardBranchMarker 36b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoextends SimplifiedVisitor 37b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimplements InstructionVisitor 38b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato{ 39b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Implementations for InstructionVisitor. 40b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 41b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {} 42b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 43b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 44b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato public void visitBranchInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, BranchInstruction branchInstruction) 45b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 46b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato markBackwardBranch(method, branchInstruction.branchOffset); 47b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 48b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 49b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 50b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato public void visitAnySwitchInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, SwitchInstruction switchInstruction) 51b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 52b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato markBackwardBranch(method, switchInstruction.defaultOffset); 53b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 54b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato for (int index = 0; index < switchInstruction.jumpOffsets.length; index++) 55b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 56b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato markBackwardBranch(method, switchInstruction.jumpOffsets[index]); 57b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 58b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 59b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 60b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 61b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Small utility methods. 62b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 63b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato /** 64b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * Marks the given method if the given branch offset is negative. 65b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato */ 66b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato private void markBackwardBranch(Method method, int branchOffset) 67b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 68b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (branchOffset < 0) 69b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 70b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato setBranchesBackward(method); 71b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 72b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 73b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 74b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 75b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato private static void setBranchesBackward(Method method) 76b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 77b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato MethodOptimizationInfo info = MethodOptimizationInfo.getMethodOptimizationInfo(method); 78b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (info != null) 79b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 80b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato info.setBranchesBackward(); 81b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 82b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 83b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 84b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 85b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato public static boolean branchesBackward(Method method) 86b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 87b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato MethodOptimizationInfo info = MethodOptimizationInfo.getMethodOptimizationInfo(method); 88b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato return info == null || info.branchesBackward(); 89b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 90b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato} 91