From: "Daniel P. Berrangé" <berrange@redhat.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Wielaard <mark@klomp.org>, dwarves@vger.kernel.org
Subject: Re: [PATCH/RFC] Re: DWARF5 DW_AT_data_bit_offset
Date: Thu, 28 Jan 2021 12:54:43 +0000 [thread overview]
Message-ID: <20210128125443.GI3832029@redhat.com> (raw)
In-Reply-To: <20210128121122.GA775562@kernel.org>
On Thu, Jan 28, 2021 at 09:11:22AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Thu, Jan 21, 2021 at 12:35:16PM +0100, Mark Wielaard escreveu:
> > On Fri, Oct 02, 2020 at 06:18:19PM -0300, Arnaldo Carvalho de Melo wrote:
> > > Em Fri, Oct 02, 2020 at 06:11:06PM +0200, Mark Wielaard escreveu:
> > > > Seems pahole with a recent version of elfutils libdw already handles
> > > > most DWARF5 encodings. One thing it doesn't handle yet is
> > > > DW_AT_data_bit_offset (this is actually a DWARF4 thing, but gcc only
> > > > emits it for -gdwarf-5).
>
> <SNIP>
>
> > > > $ gcc -gdwarf-5 -c bf.c
> > > > $ ./pahole ./bf.o
> > > > DW_AT_<0xd>=0x21
> > > > DW_AT_<0xd>=0x21
> > > > DW_AT_<0xd>=0x21
> > > > struct pea {
> > > > int type; /* 0 4 */
> > > > static long int a; /* 0 0 */
> > > > static long int b; /* 0 0 */
> > > > static long int c; /* 0 0 */
> > > >
> > > > /* size: 8, cachelines: 1, members: 1, static members: 3 */
> > > > /* padding: 4 */
> > > > /* last cacheline: 8 bytes */
> > > > };
>
> > > > Note that GCC11 might default to DWARF5.
>
> > > Thanks for the detailed report, I'm releasing v1.18 right now, will look
> > > into that for v1.19.
>
> > Note that GCC11 indeed just switched to producing DWARF5 by default.
> > It is not released yet, but already in stage4 and Fedora will start
> > doing a mass-rebuild with it soon to shake out the last remaining bugs.
>
> So, 1.20 will have the fix below, please check if what is in:
>
> https://git.kernel.org/pub/scm/devel/pahole/pahole.git/log/?h=DW_AT_data_bit_offset
>
> Fixes it for you, the cset with all the tests performed is this one:
>
> https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?h=DW_AT_data_bit_offset&id=a77f039bb49bc97badf938049245f013fe3de4aa
>
> Now looking at https://bugzilla.redhat.com/show_bug.cgi?id=1919965 ...
The XDR generated code example I give in that bug *does* appear
to be fixed when using your DW_AT_data_bit_offset branch.
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
next prev parent reply other threads:[~2021-01-28 12:56 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-02 16:11 DWARF5 DW_AT_data_bit_offset Mark Wielaard
2020-10-02 21:18 ` Arnaldo Carvalho de Melo
2021-01-21 11:35 ` Mark Wielaard
2021-01-28 12:11 ` [PATCH/RFC] " Arnaldo Carvalho de Melo
2021-01-28 12:54 ` Daniel P. Berrangé [this message]
2021-01-28 13:48 ` Arnaldo Carvalho de Melo
2021-01-28 13:54 ` Arnaldo Carvalho de Melo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210128125443.GI3832029@redhat.com \
--to=berrange@redhat.com \
--cc=acme@kernel.org \
--cc=dwarves@vger.kernel.org \
--cc=mark@klomp.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).