code: public int getLineNumber(Location start) {
          LineNumberTableAttr table = mOldLineNumberTable;
          if (table == null) {
              table = mLineNumberTable;
          }
  
          if (table == null || start.getLocation() < 0) {
              return -1;
          } else {
              return table.getLineNumber(start);
          }
      }
docs: Returns the line number in the source code from the given bytecode
  address (start_pc).
  
  @return -1 if no line number is mapped for the start_pc.