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RE: [PATCH 13/17] btrace: non-stop
- From: "Metzger, Markus T" <markus dot t dot metzger at intel dot com>
- To: Pedro Alves <palves at redhat dot com>
- Cc: "gdb-patches at sourceware dot org" <gdb-patches at sourceware dot org>
- Date: Wed, 9 Sep 2015 12:20:49 +0000
- Subject: RE: [PATCH 13/17] btrace: non-stop
- Authentication-results: sourceware.org; auth=none
- References: <1441794909-32718-1-git-send-email-markus dot t dot metzger at intel dot com> <1441794909-32718-14-git-send-email-markus dot t dot metzger at intel dot com> <55F01DEC dot 4030209 at redhat dot com>
> -----Original Message-----
> From: Pedro Alves [mailto:palves@redhat.com]
> Sent: Wednesday, September 9, 2015 1:54 PM
> To: Metzger, Markus T
> Cc: gdb-patches@sourceware.org
> Subject: Re: [PATCH 13/17] btrace: non-stop
>
> On 09/09/2015 11:35 AM, Markus Metzger wrote:
>
> > +# make sure $line matches the full expected output per thread.
> > +# and let's hope that GDB never mixes the output from different threads.
> > +#
> > +# this is quite fragile, mostly because the prompt appears somewhere in
> > +# the middle of the output.
> > +proc gdb_cont_to { threads cmd line nthreads } {
> > + global gdb_prompt
> > + set full_cmd "thread apply $threads $cmd"
> > + set prompt_seen 0
> > +
> > + send_gdb "$full_cmd\n"
> > +
> > + for {set i 0} {$i < $nthreads} {incr i} {
> > + set test "$full_cmd: thread $i"
> > +
> > + # check for the prompt. it may be in front of one of the lines we
> > + # try to match.
> > + gdb_test_multiple "" "$test: check prompt" {
> > + -notransfer -re "$gdb_prompt " {
> > + set prompt_seen 1
> > + }
> > + }
> > +
>
> Hmmm. I'm not sure I'm missing some subtlety, but it seems to me
> that if you used -notransfer, then the prompt will still be in the buffer,
> and ...
>
> > + # check for the line. and for a typical error.
> > + gdb_test_multiple "" $test {
> > + -re "Cannot execute this command \[^\\\r\\\n\]* is running\." {
> > + fail $test
> > + }
> > + -re "$line\[^\\\r\\\n\]*\r\n" {
> > + pass $test
> > + }
> > + }
>
> ... thus this gdb_test_multiple can trip on it and issue a fail.
As far as I understand expect, the above gdb_test_multiple would
simply skip the $gdb_prompt at the beginning of the line.
That's why I'm trying to detect it with a separate gdb_test_multiple
above. I use -notransfer so I can still analyse the line for the expected
output.
> Wouldn't this instead work?
>
> gdb_test_multiple "" $test {
> -re "Cannot execute this command \[^\\\r\\\n\]* is running\." {
> fail $test
> }
> -re "$line\[^\\\r\\\n\]*\r\n" {
> pass $test
> }
> -re "$gdb_prompt " {
> set prompt_seen 1
> exp_continue
> }
> }
Wouldn't the 1st or 2nd pattern skip any $gdb_prompt before the pattern?
For the "Cannot execute..." pattern, I could add "^" but this will be difficult
for the $line pattern.
Does the 3rd pattern consume just the $gdb_prompt or the entire line?
This non-stop testing is quite difficult. I also have not found too many
examples when I searched for "non-stop".
thanks,
Markus.
Intel Deutschland GmbH
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