The script that generates the waterfall summary report needs options/arguments, to allow customizing the reports: generating report for only the main waterfall builders or only the rotating builders or only a failures report, or omitting the failures report.

It would also be nice to have the option of running the report without updating all the data files.

In addition, we've started using llvm-next in the rotating builders; the waterfall summary report should be updated to report on that.