Re: [RFC] perf tools: Filter out hidden symbols from labels

Arnaldo Carvalho de Melo
2019-01-16T13:31:22Z

Em Wed, Jan 16, 2019 at 11:38:30AM +0000, Nick Clifton escreveu:
> Hi Guys,
>
>
> >> Humm, it would be nice for perf annotate to show those options when one
> >> navigates the annotation,
>
> Usually the command line options can also be found in the debug info for
> the executable. Assuming it has not been stripped, of course.
>
> One of the advantages of the annobin strategy of using ELF notes is that
> these are not stripped from executables...
>
> Unfortunately the annobin notes will probably not be very helpful as they
> only record a minor subset of the typical gcc command line options.
> (Specifically: -O, -g, -D_FORTIFY_SOURCE, -D_GLIBCXX_ASSERTIONS,
> -fcf-protection, -fpic (and variants), -fshort-enum, -fstack-clash-protection,
> -fstack-protector, -mstackrealign, -fexceptions).

Humm, is -fno-omit-frame-pointer there by any chance? :-)

> >> Is there any library that gets those
> >> annotations and put them in some linked list that we could use in
> >> tools/perf/?
>
> Sorry - no such library exists.

No problem...

> > If it's just an ELF note, we could parse it directly.

As we already parse some of the ELF notes, like the buildid, so just one
more to read and make available in the TUI somehow, should be handy.

> > https://developers.redhat.com/blog/2018/02/20/annobin-storing-information-binaries/
>
> Exactly - and what a great blog author that person is ... :-)

:-)

- Arnaldo