langtools/src/share/classes/com/sun/tools/javac/jvm/CRTable.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2001, 2012, 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.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * 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 com.sun.tools.javac.jvm;

 import java.util.*;

 import com.sun.tools.javac.tree.*;
 import com.sun.tools.javac.util.*;
 import com.sun.tools.javac.util.List;
 import com.sun.tools.javac.tree.JCTree.*;
 import com.sun.tools.javac.tree.EndPosTable;

 /** This class contains the CharacterRangeTable for some method
  *  and the hashtable for mapping trees or lists of trees to their
  *  ending positions.
  *
  *  <p><b>This is NOT part of any supported API.
  *  If you write code that depends on this, you do so at your own risk.
  *  This code and its internal interfaces are subject to change or
  *  deletion without notice.</b>
  */
 public class CRTable
 implements CRTFlags {

     private final boolean crtDebug = false;

     /** The list of CRTable entries.
      */
     private ListBuffer<CRTEntry> entries = new ListBuffer<>();

     /** The hashtable for source positions.
      */
     private Map<Object,SourceRange> positions = new HashMap<>();

     /** The object for ending positions stored in the parser.
      */
     private EndPosTable endPosTable;

     /** The tree of the method this table is intended for.
      *  We should traverse this tree to get source ranges.
      */
     JCTree.JCMethodDecl methodTree;

     /** Constructor
      */
     public CRTable(JCTree.JCMethodDecl tree, EndPosTable endPosTable) {
         this.methodTree = tree;
         this.endPosTable = endPosTable;
     }

     /** Create a new CRTEntry and add it to the entries.
      *  @param tree     The tree or the list of trees for which
      *                  we are storing the code pointers.
      *  @param flags    The set of flags designating type of the entry.
      *  @param startPc  The starting code position.
      *  @param endPc    The ending code position.
      */
     public void put(Object tree, int flags, int startPc, int endPc) {
         entries.append(new CRTEntry(tree, flags, startPc, endPc));
     }

     /** Compute source positions and write CRT to the databuf.
      *  @param databuf  The buffer to write bytecodes to.
      */
     public int writeCRT(ByteBuffer databuf, Position.LineMap lineMap, Log log) {

         int crtEntries = 0;

         // compute source positions for the method
         new SourceComputer().csp(methodTree);

         for (List<CRTEntry> l = entries.toList(); l.nonEmpty(); l = l.tail) {

             CRTEntry entry = l.head;

             // eliminate entries that do not produce bytecodes:
             // for example, empty blocks and statements
             if (entry.startPc == entry.endPc)
                 continue;

             SourceRange pos = positions.get(entry.tree);
             Assert.checkNonNull(pos, "CRT: tree source positions are undefined");
             if ((pos.startPos == Position.NOPOS) || (pos.endPos == Position.NOPOS))
                 continue;

             if (crtDebug) {
                 System.out.println("Tree: " + entry.tree + ", type:" + getTypes(entry.flags));
                 System.out.print("Start: pos = " + pos.startPos + ", pc = " + entry.startPc);
             }

             // encode startPos into line/column representation
             int startPos = encodePosition(pos.startPos, lineMap, log);
             if (startPos == Position.NOPOS)
                 continue;

             if (crtDebug) {
                 System.out.print("End:   pos = " + pos.endPos + ", pc = " + (entry.endPc - 1));
             }

             // encode endPos into line/column representation
             int endPos = encodePosition(pos.endPos, lineMap, log);
             if (endPos == Position.NOPOS)
                 continue;

             // write attribute
             databuf.appendChar(entry.startPc);
             // 'endPc - 1' because endPc actually points to start of the next command
             databuf.appendChar(entry.endPc - 1);
             databuf.appendInt(startPos);
             databuf.appendInt(endPos);
             databuf.appendChar(entry.flags);

             crtEntries++;
         }

         return crtEntries;
     }

     /** Return the number of the entries.
      */
     public int length() {
         return entries.length();
     }

     /** Return string describing flags enabled.
      */
     private String getTypes(int flags) {
         String types = "";
         if ((flags & CRT_STATEMENT)       != 0) types += " CRT_STATEMENT";
         if ((flags & CRT_BLOCK)           != 0) types += " CRT_BLOCK";
         if ((flags & CRT_ASSIGNMENT)      != 0) types += " CRT_ASSIGNMENT";
         if ((flags & CRT_FLOW_CONTROLLER) != 0) types += " CRT_FLOW_CONTROLLER";
         if ((flags & CRT_FLOW_TARGET)     != 0) types += " CRT_FLOW_TARGET";
         if ((flags & CRT_INVOKE)          != 0) types += " CRT_INVOKE";
         if ((flags & CRT_CREATE)          != 0) types += " CRT_CREATE";
         if ((flags & CRT_BRANCH_TRUE)     != 0) types += " CRT_BRANCH_TRUE";
         if ((flags & CRT_BRANCH_FALSE)    != 0) types += " CRT_BRANCH_FALSE";
         return types;
     }

     /** Source file positions in CRT are integers in the format:
      *  {@literal line-number << LINESHIFT + column-number }
      */
      private int encodePosition(int pos, Position.LineMap lineMap, Log log) {
          int line = lineMap.getLineNumber(pos);
          int col = lineMap.getColumnNumber(pos);
          int new_pos = Position.encodePosition(line, col);
          if (crtDebug) {
              System.out.println(", line = " + line + ", column = " + col +
                                 ", new_pos = " + new_pos);
          }
          if (new_pos == Position.NOPOS)
              log.warning(pos, "position.overflow", line);

         return new_pos;
      }

 /* ************************************************************************
  * Traversal methods
  *************************************************************************/

     /**
      *  This class contains methods to compute source positions for trees.
      *  Extends Tree.Visitor to traverse the abstract syntax tree.
      */
     class SourceComputer extends JCTree.Visitor {

         /** The result of the tree traversal methods.
          */
         SourceRange result;

         /** Visitor method: compute source positions for a single node.
          */
         public SourceRange csp(JCTree tree) {
             if (tree == null) return null;
             tree.accept(this);
             if (result != null) {
                 positions.put(tree, result);
             }
             return result;
         }

         /** Visitor method: compute source positions for a list of nodes.
          */
         public SourceRange csp(List<? extends JCTree> trees) {
             if ((trees == null) || !(trees.nonEmpty())) return null;
             SourceRange list_sr = new SourceRange();
             for (List<? extends JCTree> l = trees; l.nonEmpty(); l = l.tail) {
                 list_sr.mergeWith(csp(l.head));
             }
             positions.put(trees, list_sr);
             return list_sr;
         }

         /**  Visitor method: compute source positions for
          *    a list of case blocks of switch statements.
          */
         public SourceRange cspCases(List<JCCase> trees) {
             if ((trees == null) || !(trees.nonEmpty())) return null;
             SourceRange list_sr = new SourceRange();
             for (List<JCCase> l = trees; l.nonEmpty(); l = l.tail) {
                 list_sr.mergeWith(csp(l.head));
             }
             positions.put(trees, list_sr);
             return list_sr;
         }

         /**  Visitor method: compute source positions for
          *   a list of catch clauses in try statements.
          */
         public SourceRange cspCatchers(List<JCCatch> trees) {
             if ((trees == null) || !(trees.nonEmpty())) return null;
             SourceRange list_sr = new SourceRange();
             for (List<JCCatch> l = trees; l.nonEmpty(); l = l.tail) {
                 list_sr.mergeWith(csp(l.head));
             }
             positions.put(trees, list_sr);
             return list_sr;
         }

         public void visitMethodDef(JCMethodDecl tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.body));
             result = sr;
         }

         public void visitVarDef(JCVariableDecl tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             csp(tree.vartype);
             sr.mergeWith(csp(tree.init));
             result = sr;
         }

         public void visitSkip(JCSkip tree) {
             // endPos is the same as startPos for the empty statement
             SourceRange sr = new SourceRange(startPos(tree), startPos(tree));
             result = sr;
         }

         public void visitBlock(JCBlock tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             csp(tree.stats);    // doesn't compare because block's ending position is defined
             result = sr;
         }

         public void visitDoLoop(JCDoWhileLoop tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.body));
             sr.mergeWith(csp(tree.cond));
             result = sr;
         }

         public void visitWhileLoop(JCWhileLoop tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.cond));
             sr.mergeWith(csp(tree.body));
             result = sr;
         }

         public void visitForLoop(JCForLoop tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.init));
             sr.mergeWith(csp(tree.cond));
             sr.mergeWith(csp(tree.step));
             sr.mergeWith(csp(tree.body));
             result = sr;
         }

         public void visitForeachLoop(JCEnhancedForLoop tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.var));
             sr.mergeWith(csp(tree.expr));
             sr.mergeWith(csp(tree.body));
             result = sr;
         }

         public void visitLabelled(JCLabeledStatement tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.body));
             result = sr;
         }

         public void visitSwitch(JCSwitch tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.selector));
             sr.mergeWith(cspCases(tree.cases));
             result = sr;
         }

         public void visitCase(JCCase tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.pat));
             sr.mergeWith(csp(tree.stats));
             result = sr;
         }

         public void visitSynchronized(JCSynchronized tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.lock));
             sr.mergeWith(csp(tree.body));
             result = sr;
         }

         public void visitTry(JCTry tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.resources));
             sr.mergeWith(csp(tree.body));
             sr.mergeWith(cspCatchers(tree.catchers));
             sr.mergeWith(csp(tree.finalizer));
             result = sr;
         }

         public void visitCatch(JCCatch tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.param));
             sr.mergeWith(csp(tree.body));
             result = sr;
         }

         public void visitConditional(JCConditional tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.cond));
             sr.mergeWith(csp(tree.truepart));
             sr.mergeWith(csp(tree.falsepart));
             result = sr;
         }

         public void visitIf(JCIf tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.cond));
             sr.mergeWith(csp(tree.thenpart));
             sr.mergeWith(csp(tree.elsepart));
             result = sr;
         }

         public void visitExec(JCExpressionStatement tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.expr));
             result = sr;
         }

         public void visitBreak(JCBreak tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             result = sr;
         }

         public void visitContinue(JCContinue tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             result = sr;
         }

         public void visitReturn(JCReturn tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.expr));
             result = sr;
         }

         public void visitThrow(JCThrow tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.expr));
             result = sr;
         }

         public void visitAssert(JCAssert tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.cond));
             sr.mergeWith(csp(tree.detail));
             result = sr;
         }

         public void visitApply(JCMethodInvocation tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.meth));
             sr.mergeWith(csp(tree.args));
             result = sr;
         }

         public void visitNewClass(JCNewClass tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.encl));
             sr.mergeWith(csp(tree.clazz));
             sr.mergeWith(csp(tree.args));
             sr.mergeWith(csp(tree.def));
             result = sr;
         }

         public void visitNewArray(JCNewArray tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.elemtype));
             sr.mergeWith(csp(tree.dims));
             sr.mergeWith(csp(tree.elems));
             result = sr;
         }

         public void visitParens(JCParens tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.expr));
             result = sr;
         }

         public void visitAssign(JCAssign tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.lhs));
             sr.mergeWith(csp(tree.rhs));
             result = sr;
         }

         public void visitAssignop(JCAssignOp tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.lhs));
             sr.mergeWith(csp(tree.rhs));
             result = sr;
         }

         public void visitUnary(JCUnary tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.arg));
             result = sr;
         }

         public void visitBinary(JCBinary tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.lhs));
             sr.mergeWith(csp(tree.rhs));
             result = sr;
         }

         public void visitTypeCast(JCTypeCast tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.clazz));
             sr.mergeWith(csp(tree.expr));
             result = sr;
         }

         public void visitTypeTest(JCInstanceOf tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.expr));
             sr.mergeWith(csp(tree.clazz));
             result = sr;
         }

         public void visitIndexed(JCArrayAccess tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.indexed));
             sr.mergeWith(csp(tree.index));
             result = sr;
         }

         public void visitSelect(JCFieldAccess tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.selected));
             result = sr;
         }

         public void visitIdent(JCIdent tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             result = sr;
         }

         public void visitLiteral(JCLiteral tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             result = sr;
         }

         public void visitTypeIdent(JCPrimitiveTypeTree tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             result = sr;
         }

         public void visitTypeArray(JCArrayTypeTree tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.elemtype));
             result = sr;
         }

         public void visitTypeApply(JCTypeApply tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.clazz));
             sr.mergeWith(csp(tree.arguments));
             result = sr;
         }

         @Override
         public void visitLetExpr(LetExpr tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.defs));
             sr.mergeWith(csp(tree.expr));
             result = sr;
         }

         public void visitTypeParameter(JCTypeParameter tree) {
             SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
             sr.mergeWith(csp(tree.bounds));
             result = sr;
         }

         public void visitWildcard(JCWildcard tree) {
             result = null;
         }

         public void visitErroneous(JCErroneous tree) {
             result = null;
         }

         public void visitTree(JCTree tree) {
             Assert.error();
         }

         /** The start position of given tree.
          */
         public int startPos(JCTree tree) {
             if (tree == null) return Position.NOPOS;
             return TreeInfo.getStartPos(tree);
         }

         /** The end position of given tree, if it has
          *  defined endpos, NOPOS otherwise.
          */
         public int endPos(JCTree tree) {
             if (tree == null) return Position.NOPOS;
             return TreeInfo.getEndPos(tree, endPosTable);
         }
     }

     /** This class contains a CharacterRangeTableEntry.
      */
     static class CRTEntry {

         /** A tree or a list of trees to obtain source positions.
          */
         Object tree;

         /** The flags described in the CharacterRangeTable spec.
          */
         int flags;

         /** The starting code position of this entry.
          */
         int startPc;

         /** The ending code position of this entry.
          */
         int endPc;

         /** Constructor */
         CRTEntry(Object tree, int flags, int startPc, int endPc) {
             this.tree = tree;
             this.flags = flags;
             this.startPc = startPc;
             this.endPc = endPc;
         }
     }


     /** This class contains source positions
      *  for some tree or list of trees.
      */
     static class SourceRange {

         /** The starting source position.
          */
         int startPos;

         /** The ending source position.
          */
         int endPos;

         /** Constructor */
         SourceRange() {
             startPos = Position.NOPOS;
             endPos = Position.NOPOS;
         }

         /** Constructor */
         SourceRange(int startPos, int endPos) {
             this.startPos = startPos;
             this.endPos = endPos;
         }

         /** Compare the starting and the ending positions
          *  of the source range and combines them assigning
          *  the widest range to this.
          */
         SourceRange mergeWith(SourceRange sr) {
             if (sr == null) return this;
             if (startPos == Position.NOPOS)
                 startPos = sr.startPos;
             else if (sr.startPos != Position.NOPOS)
                 startPos = (startPos < sr.startPos ? startPos : sr.startPos);
             if (endPos == Position.NOPOS)
                 endPos = sr.endPos;
             else if (sr.endPos != Position.NOPOS)
                 endPos = (endPos > sr.endPos ? endPos : sr.endPos);
             return this;
         }
     }

 }
	/*
	* Copyright (c) 2001, 2012, 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. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* 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 com.sun.tools.javac.jvm;

	import java.util.*;

	import com.sun.tools.javac.tree.*;
	import com.sun.tools.javac.util.*;
	import com.sun.tools.javac.util.List;
	import com.sun.tools.javac.tree.JCTree.*;
	import com.sun.tools.javac.tree.EndPosTable;

	/** This class contains the CharacterRangeTable for some method
	* and the hashtable for mapping trees or lists of trees to their
	* ending positions.
	*
	* <p><b>This is NOT part of any supported API.
	* If you write code that depends on this, you do so at your own risk.
	* This code and its internal interfaces are subject to change or
	* deletion without notice.</b>
	*/
	public class CRTable
	implements CRTFlags {

	private final boolean crtDebug = false;

	/** The list of CRTable entries.
	*/
	private ListBuffer<CRTEntry> entries = new ListBuffer<>();

	/** The hashtable for source positions.
	*/
	private Map<Object,SourceRange> positions = new HashMap<>();

	/** The object for ending positions stored in the parser.
	*/
	private EndPosTable endPosTable;

	/** The tree of the method this table is intended for.
	* We should traverse this tree to get source ranges.
	*/
	JCTree.JCMethodDecl methodTree;

	/** Constructor
	*/
	public CRTable(JCTree.JCMethodDecl tree, EndPosTable endPosTable) {
	this.methodTree = tree;
	this.endPosTable = endPosTable;
	}

	/** Create a new CRTEntry and add it to the entries.
	* @param tree The tree or the list of trees for which
	* we are storing the code pointers.
	* @param flags The set of flags designating type of the entry.
	* @param startPc The starting code position.
	* @param endPc The ending code position.
	*/
	public void put(Object tree, int flags, int startPc, int endPc) {
	entries.append(new CRTEntry(tree, flags, startPc, endPc));
	}

	/** Compute source positions and write CRT to the databuf.
	* @param databuf The buffer to write bytecodes to.
	*/
	public int writeCRT(ByteBuffer databuf, Position.LineMap lineMap, Log log) {

	int crtEntries = 0;

	// compute source positions for the method
	new SourceComputer().csp(methodTree);

	for (List<CRTEntry> l = entries.toList(); l.nonEmpty(); l = l.tail) {

	CRTEntry entry = l.head;

	// eliminate entries that do not produce bytecodes:
	// for example, empty blocks and statements
	if (entry.startPc == entry.endPc)
	continue;

	SourceRange pos = positions.get(entry.tree);
	Assert.checkNonNull(pos, "CRT: tree source positions are undefined");
	if ((pos.startPos == Position.NOPOS) \|\| (pos.endPos == Position.NOPOS))
	continue;

	if (crtDebug) {
	System.out.println("Tree: " + entry.tree + ", type:" + getTypes(entry.flags));
	System.out.print("Start: pos = " + pos.startPos + ", pc = " + entry.startPc);
	}

	// encode startPos into line/column representation
	int startPos = encodePosition(pos.startPos, lineMap, log);
	if (startPos == Position.NOPOS)
	continue;

	if (crtDebug) {
	System.out.print("End: pos = " + pos.endPos + ", pc = " + (entry.endPc - 1));
	}

	// encode endPos into line/column representation
	int endPos = encodePosition(pos.endPos, lineMap, log);
	if (endPos == Position.NOPOS)
	continue;

	// write attribute
	databuf.appendChar(entry.startPc);
	// 'endPc - 1' because endPc actually points to start of the next command
	databuf.appendChar(entry.endPc - 1);
	databuf.appendInt(startPos);
	databuf.appendInt(endPos);
	databuf.appendChar(entry.flags);

	crtEntries++;
	}

	return crtEntries;
	}

	/** Return the number of the entries.
	*/
	public int length() {
	return entries.length();
	}

	/** Return string describing flags enabled.
	*/
	private String getTypes(int flags) {
	String types = "";
	if ((flags & CRT_STATEMENT) != 0) types += " CRT_STATEMENT";
	if ((flags & CRT_BLOCK) != 0) types += " CRT_BLOCK";
	if ((flags & CRT_ASSIGNMENT) != 0) types += " CRT_ASSIGNMENT";
	if ((flags & CRT_FLOW_CONTROLLER) != 0) types += " CRT_FLOW_CONTROLLER";
	if ((flags & CRT_FLOW_TARGET) != 0) types += " CRT_FLOW_TARGET";
	if ((flags & CRT_INVOKE) != 0) types += " CRT_INVOKE";
	if ((flags & CRT_CREATE) != 0) types += " CRT_CREATE";
	if ((flags & CRT_BRANCH_TRUE) != 0) types += " CRT_BRANCH_TRUE";
	if ((flags & CRT_BRANCH_FALSE) != 0) types += " CRT_BRANCH_FALSE";
	return types;
	}

	/** Source file positions in CRT are integers in the format:
	* {@literal line-number << LINESHIFT + column-number }
	*/
	private int encodePosition(int pos, Position.LineMap lineMap, Log log) {
	int line = lineMap.getLineNumber(pos);
	int col = lineMap.getColumnNumber(pos);
	int new_pos = Position.encodePosition(line, col);
	if (crtDebug) {
	System.out.println(", line = " + line + ", column = " + col +
	", new_pos = " + new_pos);
	}
	if (new_pos == Position.NOPOS)
	log.warning(pos, "position.overflow", line);

	return new_pos;
	}

	/* ************************************************************************
	* Traversal methods
	*************************************************************************/

	/**
	* This class contains methods to compute source positions for trees.
	* Extends Tree.Visitor to traverse the abstract syntax tree.
	*/
	class SourceComputer extends JCTree.Visitor {

	/** The result of the tree traversal methods.
	*/
	SourceRange result;

	/** Visitor method: compute source positions for a single node.
	*/
	public SourceRange csp(JCTree tree) {
	if (tree == null) return null;
	tree.accept(this);
	if (result != null) {
	positions.put(tree, result);
	}
	return result;
	}

	/** Visitor method: compute source positions for a list of nodes.
	*/
	public SourceRange csp(List<? extends JCTree> trees) {
	if ((trees == null) \|\| !(trees.nonEmpty())) return null;
	SourceRange list_sr = new SourceRange();
	for (List<? extends JCTree> l = trees; l.nonEmpty(); l = l.tail) {
	list_sr.mergeWith(csp(l.head));
	}
	positions.put(trees, list_sr);
	return list_sr;
	}

	/** Visitor method: compute source positions for
	* a list of case blocks of switch statements.
	*/
	public SourceRange cspCases(List<JCCase> trees) {
	if ((trees == null) \|\| !(trees.nonEmpty())) return null;
	SourceRange list_sr = new SourceRange();
	for (List<JCCase> l = trees; l.nonEmpty(); l = l.tail) {
	list_sr.mergeWith(csp(l.head));
	}
	positions.put(trees, list_sr);
	return list_sr;
	}

	/** Visitor method: compute source positions for
	* a list of catch clauses in try statements.
	*/
	public SourceRange cspCatchers(List<JCCatch> trees) {
	if ((trees == null) \|\| !(trees.nonEmpty())) return null;
	SourceRange list_sr = new SourceRange();
	for (List<JCCatch> l = trees; l.nonEmpty(); l = l.tail) {
	list_sr.mergeWith(csp(l.head));
	}
	positions.put(trees, list_sr);
	return list_sr;
	}

	public void visitMethodDef(JCMethodDecl tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.body));
	result = sr;
	}

	public void visitVarDef(JCVariableDecl tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	csp(tree.vartype);
	sr.mergeWith(csp(tree.init));
	result = sr;
	}

	public void visitSkip(JCSkip tree) {
	// endPos is the same as startPos for the empty statement
	SourceRange sr = new SourceRange(startPos(tree), startPos(tree));
	result = sr;
	}

	public void visitBlock(JCBlock tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	csp(tree.stats); // doesn't compare because block's ending position is defined
	result = sr;
	}

	public void visitDoLoop(JCDoWhileLoop tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.body));
	sr.mergeWith(csp(tree.cond));
	result = sr;
	}

	public void visitWhileLoop(JCWhileLoop tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.cond));
	sr.mergeWith(csp(tree.body));
	result = sr;
	}

	public void visitForLoop(JCForLoop tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.init));
	sr.mergeWith(csp(tree.cond));
	sr.mergeWith(csp(tree.step));
	sr.mergeWith(csp(tree.body));
	result = sr;
	}

	public void visitForeachLoop(JCEnhancedForLoop tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.var));
	sr.mergeWith(csp(tree.expr));
	sr.mergeWith(csp(tree.body));
	result = sr;
	}

	public void visitLabelled(JCLabeledStatement tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.body));
	result = sr;
	}

	public void visitSwitch(JCSwitch tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.selector));
	sr.mergeWith(cspCases(tree.cases));
	result = sr;
	}

	public void visitCase(JCCase tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.pat));
	sr.mergeWith(csp(tree.stats));
	result = sr;
	}

	public void visitSynchronized(JCSynchronized tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.lock));
	sr.mergeWith(csp(tree.body));
	result = sr;
	}

	public void visitTry(JCTry tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.resources));
	sr.mergeWith(csp(tree.body));
	sr.mergeWith(cspCatchers(tree.catchers));
	sr.mergeWith(csp(tree.finalizer));
	result = sr;
	}

	public void visitCatch(JCCatch tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.param));
	sr.mergeWith(csp(tree.body));
	result = sr;
	}

	public void visitConditional(JCConditional tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.cond));
	sr.mergeWith(csp(tree.truepart));
	sr.mergeWith(csp(tree.falsepart));
	result = sr;
	}

	public void visitIf(JCIf tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.cond));
	sr.mergeWith(csp(tree.thenpart));
	sr.mergeWith(csp(tree.elsepart));
	result = sr;
	}

	public void visitExec(JCExpressionStatement tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.expr));
	result = sr;
	}

	public void visitBreak(JCBreak tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	result = sr;
	}

	public void visitContinue(JCContinue tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	result = sr;
	}

	public void visitReturn(JCReturn tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.expr));
	result = sr;
	}

	public void visitThrow(JCThrow tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.expr));
	result = sr;
	}

	public void visitAssert(JCAssert tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.cond));
	sr.mergeWith(csp(tree.detail));
	result = sr;
	}

	public void visitApply(JCMethodInvocation tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.meth));
	sr.mergeWith(csp(tree.args));
	result = sr;
	}

	public void visitNewClass(JCNewClass tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.encl));
	sr.mergeWith(csp(tree.clazz));
	sr.mergeWith(csp(tree.args));
	sr.mergeWith(csp(tree.def));
	result = sr;
	}

	public void visitNewArray(JCNewArray tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.elemtype));
	sr.mergeWith(csp(tree.dims));
	sr.mergeWith(csp(tree.elems));
	result = sr;
	}

	public void visitParens(JCParens tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.expr));
	result = sr;
	}

	public void visitAssign(JCAssign tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.lhs));
	sr.mergeWith(csp(tree.rhs));
	result = sr;
	}

	public void visitAssignop(JCAssignOp tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.lhs));
	sr.mergeWith(csp(tree.rhs));
	result = sr;
	}

	public void visitUnary(JCUnary tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.arg));
	result = sr;
	}

	public void visitBinary(JCBinary tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.lhs));
	sr.mergeWith(csp(tree.rhs));
	result = sr;
	}

	public void visitTypeCast(JCTypeCast tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.clazz));
	sr.mergeWith(csp(tree.expr));
	result = sr;
	}

	public void visitTypeTest(JCInstanceOf tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.expr));
	sr.mergeWith(csp(tree.clazz));
	result = sr;
	}

	public void visitIndexed(JCArrayAccess tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.indexed));
	sr.mergeWith(csp(tree.index));
	result = sr;
	}

	public void visitSelect(JCFieldAccess tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.selected));
	result = sr;
	}

	public void visitIdent(JCIdent tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	result = sr;
	}

	public void visitLiteral(JCLiteral tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	result = sr;
	}

	public void visitTypeIdent(JCPrimitiveTypeTree tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	result = sr;
	}

	public void visitTypeArray(JCArrayTypeTree tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.elemtype));
	result = sr;
	}

	public void visitTypeApply(JCTypeApply tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.clazz));
	sr.mergeWith(csp(tree.arguments));
	result = sr;
	}

	@Override
	public void visitLetExpr(LetExpr tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.defs));
	sr.mergeWith(csp(tree.expr));
	result = sr;
	}

	public void visitTypeParameter(JCTypeParameter tree) {
	SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
	sr.mergeWith(csp(tree.bounds));
	result = sr;
	}

	public void visitWildcard(JCWildcard tree) {
	result = null;
	}

	public void visitErroneous(JCErroneous tree) {
	result = null;
	}

	public void visitTree(JCTree tree) {
	Assert.error();
	}

	/** The start position of given tree.
	*/
	public int startPos(JCTree tree) {
	if (tree == null) return Position.NOPOS;
	return TreeInfo.getStartPos(tree);
	}

	/** The end position of given tree, if it has
	* defined endpos, NOPOS otherwise.
	*/
	public int endPos(JCTree tree) {
	if (tree == null) return Position.NOPOS;
	return TreeInfo.getEndPos(tree, endPosTable);
	}
	}

	/** This class contains a CharacterRangeTableEntry.
	*/
	static class CRTEntry {

	/** A tree or a list of trees to obtain source positions.
	*/
	Object tree;

	/** The flags described in the CharacterRangeTable spec.
	*/
	int flags;

	/** The starting code position of this entry.
	*/
	int startPc;

	/** The ending code position of this entry.
	*/
	int endPc;

	/** Constructor */
	CRTEntry(Object tree, int flags, int startPc, int endPc) {
	this.tree = tree;
	this.flags = flags;
	this.startPc = startPc;
	this.endPc = endPc;
	}
	}


	/** This class contains source positions
	* for some tree or list of trees.
	*/
	static class SourceRange {

	/** The starting source position.
	*/
	int startPos;

	/** The ending source position.
	*/
	int endPos;

	/** Constructor */
	SourceRange() {
	startPos = Position.NOPOS;
	endPos = Position.NOPOS;
	}

	/** Constructor */
	SourceRange(int startPos, int endPos) {
	this.startPos = startPos;
	this.endPos = endPos;
	}

	/** Compare the starting and the ending positions
	* of the source range and combines them assigning
	* the widest range to this.
	*/
	SourceRange mergeWith(SourceRange sr) {
	if (sr == null) return this;
	if (startPos == Position.NOPOS)
	startPos = sr.startPos;
	else if (sr.startPos != Position.NOPOS)
	startPos = (startPos < sr.startPos ? startPos : sr.startPos);
	if (endPos == Position.NOPOS)
	endPos = sr.endPos;
	else if (sr.endPos != Position.NOPOS)
	endPos = (endPos > sr.endPos ? endPos : sr.endPos);
	return this;
	}
	}

	}