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 * Copyright (c) 2001, 2019, 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.
 *
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package com.sun.tools.javac.jvm;

import java.util.*;

import com.sun.tools.javac.resources.CompilerProperties.Warnings;
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;
import com.sun.tools.javac.tree.JCTree.JCSwitchExpression;

This class contains the CharacterRangeTable for some method
 and the hashtable for mapping trees or lists of trees to their
 ending positions.
 
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.
/** 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.
/** The list of CRTable entries.
     */
    private ListBuffer<CRTEntry> entries = new ListBuffer<>();

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

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

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

    
Return string describing flags enabled.
/** 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: line-number << LINESHIFT + column-number  /** 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, Warnings.PositionOverflow(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.
/**
     *  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.
/** The result of the tree traversal methods.
         */
        SourceRange result;

        
Visitor method: compute source positions for a single node.
/** 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.
/** 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.
/**  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.
/**  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;
        }

        @Override
        public void visitSwitchExpression(JCSwitchExpression 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.pats));
            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 visitYield(JCYield 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.pattern));
            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;
        }

        @Override
        public void visitTypeUnion(JCTypeUnion tree) {
            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));
            sr.mergeWith(csp(tree.alternatives));
            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.
/** 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.
/** 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.
/** This class contains a CharacterRangeTableEntry.
     */
    static class CRTEntry {

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

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

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

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

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

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

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

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

        
Constructor /** 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.
/** 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;
        }
    }

}