diff options
Diffstat (limited to 'third_party/java/proguard/proguard5.3.3/src/proguard/optimize/peephole/NopRemover.java')
-rw-r--r-- | third_party/java/proguard/proguard5.3.3/src/proguard/optimize/peephole/NopRemover.java | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/third_party/java/proguard/proguard5.3.3/src/proguard/optimize/peephole/NopRemover.java b/third_party/java/proguard/proguard5.3.3/src/proguard/optimize/peephole/NopRemover.java new file mode 100644 index 0000000000..fb40bea624 --- /dev/null +++ b/third_party/java/proguard/proguard5.3.3/src/proguard/optimize/peephole/NopRemover.java @@ -0,0 +1,89 @@ +/* + * ProGuard -- shrinking, optimization, obfuscation, and preverification + * of Java bytecode. + * + * Copyright (c) 2002-2017 Eric Lafortune @ GuardSquare + * + * 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.optimize.peephole; + +import proguard.classfile.*; +import proguard.classfile.attribute.CodeAttribute; +import proguard.classfile.editor.CodeAttributeEditor; +import proguard.classfile.instruction.*; +import proguard.classfile.instruction.visitor.InstructionVisitor; +import proguard.classfile.util.SimplifiedVisitor; + +/** + * This InstructionVisitor removes all nop instructions that it encounters. + * + * @author Eric Lafortune + */ +public class NopRemover +extends SimplifiedVisitor +implements InstructionVisitor +{ + private final CodeAttributeEditor codeAttributeEditor; + private final InstructionVisitor extraInstructionVisitor; + + + /** + * Creates a new NopRemover. + * @param codeAttributeEditor a code editor that can be used for + * accumulating changes to the code. + */ + public NopRemover(CodeAttributeEditor codeAttributeEditor) + { + this(codeAttributeEditor, null); + } + + + /** + * Creates a new NopRemover. + * @param codeAttributeEditor a code editor that can be used for + * accumulating changes to the code. + * @param extraInstructionVisitor an optional extra visitor for all removed + * nop instructions. + */ + public NopRemover(CodeAttributeEditor codeAttributeEditor, + InstructionVisitor extraInstructionVisitor) + { + this.codeAttributeEditor = codeAttributeEditor; + this.extraInstructionVisitor = extraInstructionVisitor; + } + + + // Implementations for InstructionVisitor. + + public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {} + + + public void visitSimpleInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, SimpleInstruction simpleInstruction) + { + // Check if the instruction is a nop instruction. + if (simpleInstruction.opcode == InstructionConstants.OP_NOP && + !codeAttributeEditor.isModified(offset)) + { + codeAttributeEditor.deleteInstruction(offset); + + // Visit the instruction, if required. + if (extraInstructionVisitor != null) + { + extraInstructionVisitor.visitSimpleInstruction(clazz, method, codeAttribute, offset, simpleInstruction); + } + } + } +} |