content: /*******************************************************************************
   * Copyright (c) 2009, 2019 Mountainminds GmbH & Co. KG and Contributors
   * All rights reserved. This program and the accompanying materials
   * are made available under the terms of the Eclipse Public License v1.0
   * which accompanies this distribution, and is available at
   * http://www.eclipse.org/legal/epl-v10.html
   *
   * Contributors:
   *    Marc R. Hoffmann - initial API and implementation
   *    
   *******************************************************************************/
  package org.jacoco.core.internal.flow;
  
  import org.jacoco.core.internal.instr.InstrSupport;
  import org.objectweb.asm.Label;
  import org.objectweb.asm.MethodVisitor;
  import org.objectweb.asm.commons.JSRInlinerAdapter;
  
  /**
   * This method visitor fixes two potential issues with Java byte code:
   * 
   * <ul>
   * <li>Remove JSR/RET instructions by inlining subroutines which are deprecated
   * since Java 6. The RET statement complicates control flow analysis as the jump
   * target is not explicitly given.</li>
   * <li>Remove code attributes line number and local variable name if they point
   * to invalid offsets which some tools create. When writing out such invalid
   * labels with ASM class files do not verify any more.</li>
   * </ul>
   */
  class MethodSanitizer extends JSRInlinerAdapter {
  
  	MethodSanitizer(final MethodVisitor mv, final int access,
  			final String name, final String desc, final String signature,
  			final String[] exceptions) {
  		super(InstrSupport.ASM_API_VERSION, mv, access, name, desc, signature,
  				exceptions);
  	}
  
  	@Override
  	public void visitLocalVariable(final String name, final String desc,
  			final String signature, final Label start, final Label end,
  			final int index) {
  		// Here we rely on the usage of the info fields by the tree API. If the
  		// labels have been properly used before the info field contains a
  		// reference to the LabelNode, otherwise null.
  		if (start.info != null && end.info != null) {
  			super.visitLocalVariable(name, desc, signature, start, end, index);
  		}
  	}
  
  	@Override
  	public void visitLineNumber(final int line, final Label start) {
  		// Here we rely on the usage of the info fields by the tree API. If the
  		// labels have been properly used before the info field contains a
  		// reference to the LabelNode, otherwise null.
  		if (start.info != null) {
  			super.visitLineNumber(line, start);
  		}
  	}
  
  }
  