feature idea: upto

[Roland McGrath <roland at redhat dot com>]

A common pattern for me is to hit a breakpoint or signal/crash,
and then "up" and hit return until I'm where I want to be.
When it's many frames I do "bt" and then "f N" after eyeballing
the particular frame.  

With today's programs, the "bt" output can have really long lines (e.g. 
huge C++ names, calls with many/long-valued arguments) so the quick
eyeball scan is not so quick any more.

Some common eyeball-based algorithms seem automatable:

upto "a frame with source"
upto source foobar.c
upto source */myapp/*
upto shlib foo.so*
upto exec			# not shlib
upto func
upto funcpfx_*
upto cl::func(over,load)
upto cl::			# any method/func with this ns/class prefix
upto foo.c:27 where arg==17	# skip frames where !expr
upto where arg==23		# also skip frames where expr not resolvable
upto where $r13 == 27		# cond can apply to any context

Perhaps some other dwimmy options too, like "upto mine" which is sort of
"upto source skipping /usr/include/* /usr/src/debug/*" or some stranger
heuristic.  (Maybe something like upto a frame whose source line's file
name shares a longish prefix with the executable, or with cwd, or something.)


Thanks,
Roland