code: 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;
       }
docs: Source file positions in CRT are integers in the format:
  {@literal line-number << LINESHIFT + column-number }