hotspot/agent/src/share/classes/sun/jvm/hotspot/jdi/ConcreteMethodImpl.java - edge/openjdk - Git at Google

 /*
  * Copyright (c) 2003, 2004, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code 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
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */

 package sun.jvm.hotspot.jdi;

 import com.sun.jdi.*;
 import sun.jvm.hotspot.oops.Symbol;
 import sun.jvm.hotspot.oops.LocalVariableTableElement;
 import sun.jvm.hotspot.oops.LineNumberTableElement;
 import java.util.List;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.HashMap;
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.lang.ref.SoftReference;
 import java.util.Collections;

 public class ConcreteMethodImpl extends MethodImpl {

     /*
      * A subset of the line number info that is softly cached
      */
     static private class SoftLocationXRefs {
         final String stratumID;   // The stratum of this information
         final Map lineMapper;     // Maps line number to location(s)
         final List lineLocations; // List of locations ordered by code index

         /*
          * Note: these do not necessarily correspond to
          * the line numbers of the first and last elements
          * in the lineLocations list. Use these only for bounds
          * checking and with lineMapper.
          */
         final int lowestLine;
         final int highestLine;

         SoftLocationXRefs(String stratumID, Map lineMapper, List lineLocations,
                      int lowestLine, int highestLine) {
             this.stratumID = stratumID;
             this.lineMapper = Collections.unmodifiableMap(lineMapper);
             this.lineLocations =
                 Collections.unmodifiableList(lineLocations);
             this.lowestLine = lowestLine;
             this.highestLine = highestLine;
         }
     }

     private SoftReference softBaseLocationXRefsRef;
     private SoftReference softOtherLocationXRefsRef;
     private SoftReference variablesRef = null;
     private int firstIndex = -1;
     private int lastIndex = -1;
     private Location location;
     private SoftReference bytecodesRef = null;

     ConcreteMethodImpl(VirtualMachine vm, ReferenceTypeImpl declaringType,
                sun.jvm.hotspot.oops.Method saMethod ) {
         super(vm, declaringType, saMethod);
     }

     int argSlotCount() throws AbsentInformationException {
         return (int) saMethod.getSizeOfParameters();
     }

     private SoftLocationXRefs getLocations(SDE.Stratum stratum) {
         if (stratum.isJava()) {
             return getBaseLocations();
         }
         String stratumID = stratum.id();
         SoftLocationXRefs info =
             (softOtherLocationXRefsRef == null) ? null :
                (SoftLocationXRefs)softOtherLocationXRefsRef.get();
         if (info != null && info.stratumID.equals(stratumID)) {
             return info;
         }

         List lineLocations = new ArrayList();
         Map lineMapper = new HashMap();
         int lowestLine = -1;
         int highestLine = -1;
         SDE.LineStratum lastLineStratum = null;
         SDE.Stratum baseStratum =
             declaringType.stratum(SDE.BASE_STRATUM_NAME);
         Iterator it = getBaseLocations().lineLocations.iterator();
         while(it.hasNext()) {
             LocationImpl loc = (LocationImpl)it.next();
             int baseLineNumber = loc.lineNumber(baseStratum);
             SDE.LineStratum lineStratum =
                   stratum.lineStratum(declaringType,
                                       baseLineNumber);

             if (lineStratum == null) {
                 // location not mapped in this stratum
                 continue;
             }

             int lineNumber = lineStratum.lineNumber();

             // remove unmapped and dup lines
             if ((lineNumber != -1) &&
                           (!lineStratum.equals(lastLineStratum))) {
                 lastLineStratum = lineStratum;
                 // Remember the largest/smallest line number
                 if (lineNumber > highestLine) {
                     highestLine = lineNumber;
                 }
                 if ((lineNumber < lowestLine) || (lowestLine == -1)) {
                     lowestLine = lineNumber;
                 }

                 loc.addStratumLineInfo(
                 new StratumLineInfo(stratumID,
                                       lineNumber,
                                       lineStratum.sourceName(),
                                       lineStratum.sourcePath()));

                 // Add to the location list
                 lineLocations.add(loc);

                 // Add to the line -> locations map
                 Integer key = new Integer(lineNumber);
                 List mappedLocs = (List)lineMapper.get(key);
                 if (mappedLocs == null) {
                     mappedLocs = new ArrayList(1);
                     lineMapper.put(key, mappedLocs);
                 }
                 mappedLocs.add(loc);
             }
         }

         info = new SoftLocationXRefs(stratumID,
                                 lineMapper, lineLocations,
                                 lowestLine, highestLine);
         softOtherLocationXRefsRef = new SoftReference(info);
         return info;
     }

     private SoftLocationXRefs getBaseLocations() {
         SoftLocationXRefs info = (softBaseLocationXRefsRef == null) ? null :
                                      (SoftLocationXRefs)softBaseLocationXRefsRef.get();
         if (info != null) {
             return info;
         }

         byte[] codeBuf = bytecodes();
         firstIndex = 0;
         lastIndex = codeBuf.length - 1;
         // This is odd; what is the Location of a Method?
         // A StackFrame can have a location, but a Method?
         // I guess it must be the Location for bci 0.
         location = new LocationImpl(virtualMachine(), this, 0);

         boolean hasLineInfo = saMethod.hasLineNumberTable();
         LineNumberTableElement[] lntab = null;
         int count;

         if (hasLineInfo) {
             lntab = saMethod.getLineNumberTable();
             count = lntab.length;
         } else {
             count = 0;
         }

         List lineLocations = new ArrayList(count);
         Map lineMapper = new HashMap();
         int lowestLine = -1;
         int highestLine = -1;
         for (int i = 0; i < count; i++) {
             long bci = lntab[i].getStartBCI();
             int lineNumber = lntab[i].getLineNumber();

             /*
              * Some compilers will point multiple consecutive
              * lines at the same location. We need to choose
              * one of them so that we can consistently map back
              * and forth between line and location. So we choose
              * to record only the last line entry at a particular
              * location.
              */
             if ((i + 1 == count) || (bci != lntab[i+1].getStartBCI())) {
                 // Remember the largest/smallest line number
                 if (lineNumber > highestLine) {
                     highestLine = lineNumber;
                 }
                 if ((lineNumber < lowestLine) || (lowestLine == -1)) {
                     lowestLine = lineNumber;
                 }
                 LocationImpl loc =
                     new LocationImpl(virtualMachine(), this, bci);
                 loc.addBaseLineInfo(
                     new BaseLineInfo(lineNumber, declaringType));

                 // Add to the location list
                 lineLocations.add(loc);

                 // Add to the line -> locations map
                 Integer key = new Integer(lineNumber);
                 List mappedLocs = (List)lineMapper.get(key);
                 if (mappedLocs == null) {
                     mappedLocs = new ArrayList(1);
                     lineMapper.put(key, mappedLocs);
                 }
                 mappedLocs.add(loc);
             }
         }

         info = new SoftLocationXRefs(SDE.BASE_STRATUM_NAME,
                                 lineMapper, lineLocations,
                                 lowestLine, highestLine);
         softBaseLocationXRefsRef = new SoftReference(info);
         return info;
     }

     List sourceNameFilter(List list,
                           SDE.Stratum stratum,
                           String sourceName)
                             throws AbsentInformationException {
         if (sourceName == null) {
             return list;
         } else {
             /* needs sourceName filteration */
             List locs = new ArrayList();
             Iterator it = list.iterator();
             while (it.hasNext()) {
                 LocationImpl loc = (LocationImpl)it.next();
                 if (loc.sourceName(stratum).equals(sourceName)) {
                     locs.add(loc);
                 }
             }
             return locs;
         }
     }

     public List allLineLocations(SDE.Stratum stratum, String sourceName)
         throws AbsentInformationException {
         List lineLocations = getLocations(stratum).lineLocations;

         if (lineLocations.size() == 0) {
             throw new AbsentInformationException();
         }

         return Collections.unmodifiableList(
           sourceNameFilter(lineLocations, stratum, sourceName));
     }

     public List locationsOfLine(SDE.Stratum stratum, String sourceName,
                          int lineNumber) throws AbsentInformationException {
         SoftLocationXRefs info = getLocations(stratum);

         if (info.lineLocations.size() == 0) {
             throw new AbsentInformationException();
         }

         /*
          * Find the locations which match the line number
          * passed in.
          */
         List list = (List)info.lineMapper.get(
                                   new Integer(lineNumber));

         if (list == null) {
             list = new ArrayList(0);
         }
         return Collections.unmodifiableList(
           sourceNameFilter(list, stratum, sourceName));
     }

     LineInfo codeIndexToLineInfo(SDE.Stratum stratum,
                                  long codeIndex) {
         if (firstIndex == -1) {
             getBaseLocations();
         }

         /*
          * Check for invalid code index.
          */
         if (codeIndex < firstIndex || codeIndex > lastIndex) {
             throw new InternalError(
                     "Location with invalid code index");
         }

         List lineLocations = getLocations(stratum).lineLocations;

         /*
          * Check for absent line numbers.
          */
         if (lineLocations.size() == 0) {
             return super.codeIndexToLineInfo(stratum, codeIndex);
         }

         Iterator iter = lineLocations.iterator();
         /*
          * Treat code before the beginning of the first line table
          * entry as part of the first line.  javac will generate
          * code like this for some local classes. This "prolog"
          * code contains assignments from locals in the enclosing
          * scope to synthetic fields in the local class.  Same for
          * other language prolog code.
          */
         LocationImpl bestMatch = (LocationImpl)iter.next();
         while (iter.hasNext()) {
             LocationImpl current = (LocationImpl)iter.next();
             if (current.codeIndex() > codeIndex) {
                 break;
             }
             bestMatch = current;
         }
         return bestMatch.getLineInfo(stratum);
     }

     public Location locationOfCodeIndex(long codeIndex) {
         if (firstIndex == -1) {
             getBaseLocations();
         }

         /*
          * Check for invalid code index.
          */
         if (codeIndex < firstIndex || codeIndex > lastIndex) {
             return null;
         }

         return new LocationImpl(virtualMachine(), this, codeIndex);
     }

     public List variables() throws AbsentInformationException {
         return getVariables();
     }

     public List variablesByName(String name) throws AbsentInformationException {
         List variables = getVariables();

         List retList = new ArrayList(2);
         Iterator iter = variables.iterator();
         while(iter.hasNext()) {
             LocalVariable variable = (LocalVariable)iter.next();
             if (variable.name().equals(name)) {
                 retList.add(variable);
             }
         }
         return retList;
     }

     public List arguments() throws AbsentInformationException {
         if (argumentTypeNames().size() == 0) {
             return new ArrayList(0);
         }
         List variables = getVariables();
         List retList = new ArrayList(variables.size());
         Iterator iter = variables.iterator();
         while(iter.hasNext()) {
             LocalVariable variable = (LocalVariable)iter.next();
             if (variable.isArgument()) {
                 retList.add(variable);
             }
         }
         return retList;
     }

     public byte[] bytecodes() {
         byte[] bytecodes = (bytecodesRef == null) ? null :
                                      (byte[])bytecodesRef.get();
         if (bytecodes == null) {
             bytecodes = saMethod.getByteCode();
             bytecodesRef = new SoftReference(bytecodes);
         }
         /*
          * Arrays are always modifiable, so it is a little unsafe
          * to return the cached bytecodes directly; instead, we
          * make a clone at the cost of using more memory.
          */
         return (byte[])bytecodes.clone();
     }

     public Location location() {
         if (location == null) {
             getBaseLocations();
         }
         return location;
     }

     private List getVariables() throws AbsentInformationException {
         List variables = (variablesRef == null) ? null :
                                      (List)variablesRef.get();
         if (variables != null) {
             return variables;
         }

         // if there are no locals, there won't be a LVT
         if (saMethod.getMaxLocals() == 0) {
            variables = Collections.unmodifiableList(new ArrayList(0));
            variablesRef = new SoftReference(variables);
            return variables;
         }

         if (! saMethod.hasLocalVariableTable()) {
             throw new AbsentInformationException();
         }
         //Build up the JDI view of local variable table.
         LocalVariableTableElement[] locals = saMethod.getLocalVariableTable();
         int localCount = locals.length;
         variables = new ArrayList(localCount);
         for (int ii = 0; ii < localCount; ii++) {
             String name =
                 saMethod.getConstants().getSymbolAt(locals[ii].getNameCPIndex()).asString();
             /*
              * Skip "this$*", "this+*", "this" entries because they are never real
              * variables from the JLS perspective. "this+*" is new with 1.5.
              * Instead of using '+', we check for java letter or digit to avoid
              * depending on javac's current choice of '+'.
              */
             boolean isInternalName = name.startsWith("this") &&
                   (name.length() == 4 || name.charAt(4)=='$' || !Character.isJavaIdentifierPart(name.charAt(4)));
             if (! isInternalName) {
                 int slot = locals[ii].getSlot();
                 long codeIndex = locals[ii].getStartBCI();
                 int length = locals[ii].getLength();
                 Location scopeStart = new LocationImpl(virtualMachine(),
                                                        this, codeIndex);
                 Location scopeEnd =
                     new LocationImpl(virtualMachine(), this,
                                      codeIndex + length - 1);
                 String signature =
                     saMethod.getConstants().getSymbolAt(locals[ii].getDescriptorCPIndex()).asString();

                 int genericSigIndex = locals[ii].getSignatureCPIndex();
                 String genericSignature = null;
                 if (genericSigIndex != 0) {
                     genericSignature = saMethod.getConstants().getSymbolAt(genericSigIndex).asString();
                 }

                 LocalVariable variable =
                     new LocalVariableImpl(virtualMachine(), this,
                                           slot, scopeStart, scopeEnd,
                                           name, signature, genericSignature);
                 // Add to the variable list
                 variables.add(variable);
             }
         }

         variables = Collections.unmodifiableList(variables);
         variablesRef = new SoftReference(variables);
         return variables;
     }
 }
	/*
	* Copyright (c) 2003, 2004, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation.
	*
	* This code 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
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*
	*/

	package sun.jvm.hotspot.jdi;

	import com.sun.jdi.*;
	import sun.jvm.hotspot.oops.Symbol;
	import sun.jvm.hotspot.oops.LocalVariableTableElement;
	import sun.jvm.hotspot.oops.LineNumberTableElement;
	import java.util.List;
	import java.util.Iterator;
	import java.util.Map;
	import java.util.HashMap;
	import java.util.ArrayList;
	import java.util.Comparator;
	import java.lang.ref.SoftReference;
	import java.util.Collections;

	public class ConcreteMethodImpl extends MethodImpl {

	/*
	* A subset of the line number info that is softly cached
	*/
	static private class SoftLocationXRefs {
	final String stratumID; // The stratum of this information
	final Map lineMapper; // Maps line number to location(s)
	final List lineLocations; // List of locations ordered by code index

	/*
	* Note: these do not necessarily correspond to
	* the line numbers of the first and last elements
	* in the lineLocations list. Use these only for bounds
	* checking and with lineMapper.
	*/
	final int lowestLine;
	final int highestLine;

	SoftLocationXRefs(String stratumID, Map lineMapper, List lineLocations,
	int lowestLine, int highestLine) {
	this.stratumID = stratumID;
	this.lineMapper = Collections.unmodifiableMap(lineMapper);
	this.lineLocations =
	Collections.unmodifiableList(lineLocations);
	this.lowestLine = lowestLine;
	this.highestLine = highestLine;
	}
	}

	private SoftReference softBaseLocationXRefsRef;
	private SoftReference softOtherLocationXRefsRef;
	private SoftReference variablesRef = null;
	private int firstIndex = -1;
	private int lastIndex = -1;
	private Location location;
	private SoftReference bytecodesRef = null;

	ConcreteMethodImpl(VirtualMachine vm, ReferenceTypeImpl declaringType,
	sun.jvm.hotspot.oops.Method saMethod ) {
	super(vm, declaringType, saMethod);
	}

	int argSlotCount() throws AbsentInformationException {
	return (int) saMethod.getSizeOfParameters();
	}

	private SoftLocationXRefs getLocations(SDE.Stratum stratum) {
	if (stratum.isJava()) {
	return getBaseLocations();
	}
	String stratumID = stratum.id();
	SoftLocationXRefs info =
	(softOtherLocationXRefsRef == null) ? null :
	(SoftLocationXRefs)softOtherLocationXRefsRef.get();
	if (info != null && info.stratumID.equals(stratumID)) {
	return info;
	}

	List lineLocations = new ArrayList();
	Map lineMapper = new HashMap();
	int lowestLine = -1;
	int highestLine = -1;
	SDE.LineStratum lastLineStratum = null;
	SDE.Stratum baseStratum =
	declaringType.stratum(SDE.BASE_STRATUM_NAME);
	Iterator it = getBaseLocations().lineLocations.iterator();
	while(it.hasNext()) {
	LocationImpl loc = (LocationImpl)it.next();
	int baseLineNumber = loc.lineNumber(baseStratum);
	SDE.LineStratum lineStratum =
	stratum.lineStratum(declaringType,
	baseLineNumber);

	if (lineStratum == null) {
	// location not mapped in this stratum
	continue;
	}

	int lineNumber = lineStratum.lineNumber();

	// remove unmapped and dup lines
	if ((lineNumber != -1) &&
	(!lineStratum.equals(lastLineStratum))) {
	lastLineStratum = lineStratum;
	// Remember the largest/smallest line number
	if (lineNumber > highestLine) {
	highestLine = lineNumber;
	}
	if ((lineNumber < lowestLine) \|\| (lowestLine == -1)) {
	lowestLine = lineNumber;
	}

	loc.addStratumLineInfo(
	new StratumLineInfo(stratumID,
	lineNumber,
	lineStratum.sourceName(),
	lineStratum.sourcePath()));

	// Add to the location list
	lineLocations.add(loc);

	// Add to the line -> locations map
	Integer key = new Integer(lineNumber);
	List mappedLocs = (List)lineMapper.get(key);
	if (mappedLocs == null) {
	mappedLocs = new ArrayList(1);
	lineMapper.put(key, mappedLocs);
	}
	mappedLocs.add(loc);
	}
	}

	info = new SoftLocationXRefs(stratumID,
	lineMapper, lineLocations,
	lowestLine, highestLine);
	softOtherLocationXRefsRef = new SoftReference(info);
	return info;
	}

	private SoftLocationXRefs getBaseLocations() {
	SoftLocationXRefs info = (softBaseLocationXRefsRef == null) ? null :
	(SoftLocationXRefs)softBaseLocationXRefsRef.get();
	if (info != null) {
	return info;
	}

	byte[] codeBuf = bytecodes();
	firstIndex = 0;
	lastIndex = codeBuf.length - 1;
	// This is odd; what is the Location of a Method?
	// A StackFrame can have a location, but a Method?
	// I guess it must be the Location for bci 0.
	location = new LocationImpl(virtualMachine(), this, 0);

	boolean hasLineInfo = saMethod.hasLineNumberTable();
	LineNumberTableElement[] lntab = null;
	int count;

	if (hasLineInfo) {
	lntab = saMethod.getLineNumberTable();
	count = lntab.length;
	} else {
	count = 0;
	}

	List lineLocations = new ArrayList(count);
	Map lineMapper = new HashMap();
	int lowestLine = -1;
	int highestLine = -1;
	for (int i = 0; i < count; i++) {
	long bci = lntab[i].getStartBCI();
	int lineNumber = lntab[i].getLineNumber();

	/*
	* Some compilers will point multiple consecutive
	* lines at the same location. We need to choose
	* one of them so that we can consistently map back
	* and forth between line and location. So we choose
	* to record only the last line entry at a particular
	* location.
	*/
	if ((i + 1 == count) \|\| (bci != lntab[i+1].getStartBCI())) {
	// Remember the largest/smallest line number
	if (lineNumber > highestLine) {
	highestLine = lineNumber;
	}
	if ((lineNumber < lowestLine) \|\| (lowestLine == -1)) {
	lowestLine = lineNumber;
	}
	LocationImpl loc =
	new LocationImpl(virtualMachine(), this, bci);
	loc.addBaseLineInfo(
	new BaseLineInfo(lineNumber, declaringType));

	// Add to the location list
	lineLocations.add(loc);

	// Add to the line -> locations map
	Integer key = new Integer(lineNumber);
	List mappedLocs = (List)lineMapper.get(key);
	if (mappedLocs == null) {
	mappedLocs = new ArrayList(1);
	lineMapper.put(key, mappedLocs);
	}
	mappedLocs.add(loc);
	}
	}

	info = new SoftLocationXRefs(SDE.BASE_STRATUM_NAME,
	lineMapper, lineLocations,
	lowestLine, highestLine);
	softBaseLocationXRefsRef = new SoftReference(info);
	return info;
	}

	List sourceNameFilter(List list,
	SDE.Stratum stratum,
	String sourceName)
	throws AbsentInformationException {
	if (sourceName == null) {
	return list;
	} else {
	/* needs sourceName filteration */
	List locs = new ArrayList();
	Iterator it = list.iterator();
	while (it.hasNext()) {
	LocationImpl loc = (LocationImpl)it.next();
	if (loc.sourceName(stratum).equals(sourceName)) {
	locs.add(loc);
	}
	}
	return locs;
	}
	}

	public List allLineLocations(SDE.Stratum stratum, String sourceName)
	throws AbsentInformationException {
	List lineLocations = getLocations(stratum).lineLocations;

	if (lineLocations.size() == 0) {
	throw new AbsentInformationException();
	}

	return Collections.unmodifiableList(
	sourceNameFilter(lineLocations, stratum, sourceName));
	}

	public List locationsOfLine(SDE.Stratum stratum, String sourceName,
	int lineNumber) throws AbsentInformationException {
	SoftLocationXRefs info = getLocations(stratum);

	if (info.lineLocations.size() == 0) {
	throw new AbsentInformationException();
	}

	/*
	* Find the locations which match the line number
	* passed in.
	*/
	List list = (List)info.lineMapper.get(
	new Integer(lineNumber));

	if (list == null) {
	list = new ArrayList(0);
	}
	return Collections.unmodifiableList(
	sourceNameFilter(list, stratum, sourceName));
	}

	LineInfo codeIndexToLineInfo(SDE.Stratum stratum,
	long codeIndex) {
	if (firstIndex == -1) {
	getBaseLocations();
	}

	/*
	* Check for invalid code index.
	*/
	if (codeIndex < firstIndex \|\| codeIndex > lastIndex) {
	throw new InternalError(
	"Location with invalid code index");
	}

	List lineLocations = getLocations(stratum).lineLocations;

	/*
	* Check for absent line numbers.
	*/
	if (lineLocations.size() == 0) {
	return super.codeIndexToLineInfo(stratum, codeIndex);
	}

	Iterator iter = lineLocations.iterator();
	/*
	* Treat code before the beginning of the first line table
	* entry as part of the first line. javac will generate
	* code like this for some local classes. This "prolog"
	* code contains assignments from locals in the enclosing
	* scope to synthetic fields in the local class. Same for
	* other language prolog code.
	*/
	LocationImpl bestMatch = (LocationImpl)iter.next();
	while (iter.hasNext()) {
	LocationImpl current = (LocationImpl)iter.next();
	if (current.codeIndex() > codeIndex) {
	break;
	}
	bestMatch = current;
	}
	return bestMatch.getLineInfo(stratum);
	}

	public Location locationOfCodeIndex(long codeIndex) {
	if (firstIndex == -1) {
	getBaseLocations();
	}

	/*
	* Check for invalid code index.
	*/
	if (codeIndex < firstIndex \|\| codeIndex > lastIndex) {
	return null;
	}

	return new LocationImpl(virtualMachine(), this, codeIndex);
	}

	public List variables() throws AbsentInformationException {
	return getVariables();
	}

	public List variablesByName(String name) throws AbsentInformationException {
	List variables = getVariables();

	List retList = new ArrayList(2);
	Iterator iter = variables.iterator();
	while(iter.hasNext()) {
	LocalVariable variable = (LocalVariable)iter.next();
	if (variable.name().equals(name)) {
	retList.add(variable);
	}
	}
	return retList;
	}

	public List arguments() throws AbsentInformationException {
	if (argumentTypeNames().size() == 0) {
	return new ArrayList(0);
	}
	List variables = getVariables();
	List retList = new ArrayList(variables.size());
	Iterator iter = variables.iterator();
	while(iter.hasNext()) {
	LocalVariable variable = (LocalVariable)iter.next();
	if (variable.isArgument()) {
	retList.add(variable);
	}
	}
	return retList;
	}

	public byte[] bytecodes() {
	byte[] bytecodes = (bytecodesRef == null) ? null :
	(byte[])bytecodesRef.get();
	if (bytecodes == null) {
	bytecodes = saMethod.getByteCode();
	bytecodesRef = new SoftReference(bytecodes);
	}
	/*
	* Arrays are always modifiable, so it is a little unsafe
	* to return the cached bytecodes directly; instead, we
	* make a clone at the cost of using more memory.
	*/
	return (byte[])bytecodes.clone();
	}

	public Location location() {
	if (location == null) {
	getBaseLocations();
	}
	return location;
	}

	private List getVariables() throws AbsentInformationException {
	List variables = (variablesRef == null) ? null :
	(List)variablesRef.get();
	if (variables != null) {
	return variables;
	}

	// if there are no locals, there won't be a LVT
	if (saMethod.getMaxLocals() == 0) {
	variables = Collections.unmodifiableList(new ArrayList(0));
	variablesRef = new SoftReference(variables);
	return variables;
	}

	if (! saMethod.hasLocalVariableTable()) {
	throw new AbsentInformationException();
	}
	//Build up the JDI view of local variable table.
	LocalVariableTableElement[] locals = saMethod.getLocalVariableTable();
	int localCount = locals.length;
	variables = new ArrayList(localCount);
	for (int ii = 0; ii < localCount; ii++) {
	String name =
	saMethod.getConstants().getSymbolAt(locals[ii].getNameCPIndex()).asString();
	/*
	* Skip "this$", "this+", "this" entries because they are never real
	* variables from the JLS perspective. "this+*" is new with 1.5.
	* Instead of using '+', we check for java letter or digit to avoid
	* depending on javac's current choice of '+'.
	*/
	boolean isInternalName = name.startsWith("this") &&
	(name.length() == 4 \|\| name.charAt(4)=='$' \|\| !Character.isJavaIdentifierPart(name.charAt(4)));
	if (! isInternalName) {
	int slot = locals[ii].getSlot();
	long codeIndex = locals[ii].getStartBCI();
	int length = locals[ii].getLength();
	Location scopeStart = new LocationImpl(virtualMachine(),
	this, codeIndex);
	Location scopeEnd =
	new LocationImpl(virtualMachine(), this,
	codeIndex + length - 1);
	String signature =
	saMethod.getConstants().getSymbolAt(locals[ii].getDescriptorCPIndex()).asString();

	int genericSigIndex = locals[ii].getSignatureCPIndex();
	String genericSignature = null;
	if (genericSigIndex != 0) {
	genericSignature = saMethod.getConstants().getSymbolAt(genericSigIndex).asString();
	}

	LocalVariable variable =
	new LocalVariableImpl(virtualMachine(), this,
	slot, scopeStart, scopeEnd,
	name, signature, genericSignature);
	// Add to the variable list
	variables.add(variable);
	}
	}

	variables = Collections.unmodifiableList(variables);
	variablesRef = new SoftReference(variables);
	return variables;
	}
	}