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.peephole; 22b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 23b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.*; 24b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.attribute.*; 25b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.attribute.visitor.AttributeVisitor; 26b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.editor.CodeAttributeEditor; 27b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.instruction.*; 28b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.instruction.visitor.InstructionVisitor; 29b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimport proguard.classfile.util.SimplifiedVisitor; 30b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 31b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato/** 32b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * This AttributeVisitor redirects unconditional branches so any common code 33b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * is shared, and the code preceding the branch can be removed, in the code 34b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * attributes that it visits. 35b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * 36b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * @author Eric Lafortune 37b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato */ 38b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratopublic class GotoCommonCodeReplacer 39b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoextends SimplifiedVisitor 40b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onoratoimplements AttributeVisitor, 41b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato InstructionVisitor 42b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato{ 43b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato //* 44b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato private static final boolean DEBUG = false; 45b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato /*/ 46b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato private static boolean DEBUG = true; 47b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato //*/ 48b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 49b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 50b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato private final InstructionVisitor extraInstructionVisitor; 51b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 52b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato private final BranchTargetFinder branchTargetFinder = new BranchTargetFinder(); 53b9cc48a43ed984587c939d02fba5316bf5c0df6eYing Wang private final CodeAttributeEditor codeAttributeEditor = new CodeAttributeEditor(true, false); 54b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 55b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 56b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato /** 57b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * Creates a new GotoCommonCodeReplacer. 58b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * @param extraInstructionVisitor an optional extra visitor for all replaced 59b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * goto instructions. 60b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato */ 61b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato public GotoCommonCodeReplacer(InstructionVisitor extraInstructionVisitor) 62b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 63b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato this.extraInstructionVisitor = extraInstructionVisitor; 64b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 65b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 66b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 67b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Implementations for AttributeVisitor. 68b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 69b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato public void visitAnyAttribute(Clazz clazz, Attribute attribute) {} 70b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 71b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 72b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute) 73b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 74b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato// DEBUG = 75b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato// clazz.getName().equals("abc/Def") && 76b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato// method.getName(clazz).equals("abc"); 77b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 78b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Mark all branch targets. 79b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato branchTargetFinder.visitCodeAttribute(clazz, method, codeAttribute); 80b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 81b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Reset the code attribute editor. 82b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato codeAttributeEditor.reset(codeAttribute.u4codeLength); 83b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 84b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Remap the variables of the instructions. 85b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato codeAttribute.instructionsAccept(clazz, method, this); 86b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 87b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Apply the code atribute editor. 88b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato codeAttributeEditor.visitCodeAttribute(clazz, method, codeAttribute); 89b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 90b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 91b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 92b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Implementations for InstructionVisitor. 93b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 94b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {} 95b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 96b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 97b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato public void visitBranchInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, BranchInstruction branchInstruction) 98b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 99b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Check if the instruction is an unconditional goto instruction that 100b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // isn't the target of a branch itself. 101b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato byte opcode = branchInstruction.opcode; 102b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if ((opcode == InstructionConstants.OP_GOTO || 103b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato opcode == InstructionConstants.OP_GOTO_W) && 104b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato !branchTargetFinder.isBranchTarget(offset)) 105b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 106b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int branchOffset = branchInstruction.branchOffset; 107b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int targetOffset = offset + branchOffset; 108b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 109b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Get the number of common bytes. 110b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int commonCount = commonByteCodeCount(codeAttribute, offset, targetOffset); 111b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 112b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (commonCount > 0 && 113b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato !exceptionBoundary(codeAttribute, offset, targetOffset)) 114b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 115b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (DEBUG) 116b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 117b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato System.out.println("GotoCommonCodeReplacer: "+clazz.getName()+"."+method.getName(clazz)+" (["+(offset-commonCount)+"] - "+branchInstruction.toString(offset)+" -> "+targetOffset+")"); 118b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 119b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 120b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Delete the common instructions. 121b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato for (int delta = 0; delta <= commonCount; delta++) 122b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 123b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int deleteOffset = offset - delta; 124b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (branchTargetFinder.isInstruction(deleteOffset)) 125b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 126b9cc48a43ed984587c939d02fba5316bf5c0df6eYing Wang codeAttributeEditor.clearModifications(deleteOffset); 127b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato codeAttributeEditor.deleteInstruction(deleteOffset); 128b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 129b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 130b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 131b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Redirect the goto instruction, if it is still necessary. 132b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int newBranchOffset = branchOffset - commonCount; 133b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (newBranchOffset != branchInstruction.length(offset)) 134b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 135b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato Instruction newGotoInstruction = 136b9cc48a43ed984587c939d02fba5316bf5c0df6eYing Wang new BranchInstruction(opcode, newBranchOffset).shrink(); 137b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato codeAttributeEditor.replaceInstruction(offset, 138b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato newGotoInstruction); 139b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 140b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 141b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Visit the instruction, if required. 142b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (extraInstructionVisitor != null) 143b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 144b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato extraInstructionVisitor.visitBranchInstruction(clazz, method, codeAttribute, offset, branchInstruction); 145b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 146b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 147b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 148b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 149b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 150b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 151b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Small utility methods. 152b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 153b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato /** 154b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * Returns the number of common bytes preceding the given offsets, 155b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * avoiding branches and exception blocks. 156b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato */ 157b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato private int commonByteCodeCount(CodeAttribute codeAttribute, int offset1, int offset2) 158b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 159b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Find the block of common instructions preceding it. 160b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato byte[] code = codeAttribute.code; 161b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 162b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int successfulDelta = 0; 163b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 164b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato for (int delta = 1; 165b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato delta <= offset1 && 166b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato delta <= offset2 && 167b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato offset2 - delta != offset1; 168b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato delta++) 169b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 170b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int newOffset1 = offset1 - delta; 171b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int newOffset2 = offset2 - delta; 172b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 173b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Is the code identical at both offsets? 174b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (code[newOffset1] != code[newOffset2]) 175b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 176b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato break; 177b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 178b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 179b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Are there instructions at either offset but not both? 180b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (branchTargetFinder.isInstruction(newOffset1) ^ 181b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato branchTargetFinder.isInstruction(newOffset2)) 182b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 183b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato break; 184b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 185b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 186b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Are there instructions at both offsets? 187b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (branchTargetFinder.isInstruction(newOffset1) && 188b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato branchTargetFinder.isInstruction(newOffset2)) 189b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 190b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Are the offsets involved in some branches? 191b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Note that the preverifier doesn't like initializer 192b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // invocations to be moved around. 193b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Also note that the preverifier doesn't like pop instructions 194b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // that work on different operands. 195b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (branchTargetFinder.isBranchOrigin(newOffset1) || 196b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato branchTargetFinder.isBranchTarget(newOffset1) || 197b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato branchTargetFinder.isExceptionStart(newOffset1) || 198b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato branchTargetFinder.isExceptionEnd(newOffset1) || 199b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato branchTargetFinder.isInitializer(newOffset1) || 200b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato branchTargetFinder.isExceptionStart(newOffset2) || 201b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato branchTargetFinder.isExceptionEnd(newOffset2) || 202b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato isPop(code[newOffset1])) 203b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 204b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato break; 205b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 206b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 207b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Make sure the new branch target was a branch target before, 208b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // in order not to introduce new entries in the stack map table. 209b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (branchTargetFinder.isBranchTarget(newOffset2)) 210b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 211b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato successfulDelta = delta; 212b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 213b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 214b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (branchTargetFinder.isBranchTarget(newOffset1)) 215b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 216b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato break; 217b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 218b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 219b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 220b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 221b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato return successfulDelta; 222b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 223b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 224b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 225b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato /** 226b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * Returns whether the given opcode represents a pop instruction that must 227b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * get a consistent type (pop, pop2, arraylength). 228b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato */ 229b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato private boolean isPop(byte opcode) 230b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 231b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato return opcode == InstructionConstants.OP_POP || 232b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato opcode == InstructionConstants.OP_POP2 || 233b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato opcode == InstructionConstants.OP_ARRAYLENGTH; 234b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 235b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 236b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 237b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato /** 238b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * Returns the whether there is a boundary of an exception block between 239b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato * the given offsets (including both). 240b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato */ 241b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato private boolean exceptionBoundary(CodeAttribute codeAttribute, int offset1, int offset2) 242b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 243b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Swap the offsets if the second one is smaller than the first one. 244b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (offset2 < offset1) 245b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 246b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato int offset = offset1; 247b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato offset1 = offset2; 248b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato offset2 = offset; 249b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 250b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 251b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato // Check if there is a boundary of an exception block. 252b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato for (int offset = offset1; offset <= offset2; offset++) 253b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 254b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato if (branchTargetFinder.isExceptionStart(offset) || 255b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato branchTargetFinder.isExceptionEnd(offset)) 256b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato { 257b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato return true; 258b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 259b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 260b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato 261b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato return false; 262b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato } 263b72c5c2e5482cf10117b2b25f642f7616b2326c3Joe Onorato} 264