[RFA v2 00/13] various frame filter fixes and cleanups

[Tom Tromey <tom@tromey.com>]

Here's version 2 of one my frame-filter-related patch series.  This
series rationalizes backtrace command-line parsing, fixes a few bugs,
and adds the ability to not print "elided" frames.

Reviews of v1 mostly were in June, e.g.:
https://sourceware.org/ml/gdb-patches/2017-06/msg00741.html
The series was posted here:
https://sourceware.org/ml/gdb-patches/2017-04/msg00671.html

I believe this new series addresses all the review comments.  However,
there have been changes and additions, so you will probably want to
re-read everything, and especially the new final patch.

There were a few questions last time.  Some are answered in specific
patches, but for the others:

[ about exceptions in py-framefilter.c ]

> Are any of these returning back to the Python runtime?  If so, then
> we can't let C++ exceptions cross it.

I think the answer is no.

> So "bt elide" means "elide the elided frames", not "show me the
> elided frames too".  It's fine with me, though I mildly wonder whether
> users will be confused by the "double negative".

"Elide" means "drop", so really "bt elide" should mean "drop whatever
frames are droppable".  Having "bt elide" mean "show the dropped
frames" would be confusing.  But maybe another word would be better
here, I don't know.

Tom