From: Michael Eager <eager@eagercon.com>
To: elfutils-devel@lists.fedorahosted.org
Subject: Re: [Dwarf-Discuss] Some DWARFv5 draft feedback
Date: Thu, 01 Dec 2016 11:32:05 -0800 [thread overview]
Message-ID: <58407AB5.9080308@eagercon.com> (raw)
In-Reply-To: m3h96nivir.fsf@oc1027705133.ibm.com
[-- Attachment #1: Type: text/plain, Size: 2279 bytes --]
Andreas --
Please submit comments about the Public Draft at http://dwarfstd.org/Comment.php.
On 12/01/2016 06:17 AM, Andreas Arnez wrote:
> On Thu, Dec 01 2016, Mark Wielaard wrote:
>
>> BTW. It would be handy if there were sources for the spec so one can
>> create patches for simple typos. Also it is somewhat opaque how Issues
>> are handled. Could they and any comments from the committee be sent to
>> the mailinglist to make tracking changes to the draft easier.
>
> +1.
>
>
> While we're at it, DWARF5 should improve the description of DW_OP_piece
> and DW_OP_bit_piece. AFAIK, their handling is fairly broken in all
> existing DWARF producers and consumers (certainly in GDB -- in multiple
> ways!), so even incompatible changes may not cause much harm. See my
> previous mails on this topic:
>
> http://lists.dwarfstd.org/private.cgi/dwarf-discuss-dwarfstd.org/2016-March/004229.html
> https://sourceware.org/ml/gdb/2016-01/msg00013.html
>
> E.g.:
>
> * DW_OP_bit_piece: [...] "If the location is a register, the offset is
> from the least significant bit end of the register."
>
> Is it intentional that this differs from the definition of
> DW_OP_piece, where the "placement of the piece within that register is
> defined by the ABI"? Or can it be assumed (like all current
> producers/consumers do, AFAIK) that DW_OP_piece shall behave as if it
> was a DW_OP_bit_piece with offset 0? What does the least significant
> bit end even mean, say, for a vector register? And is this really a
> useful definition for FP registers, where the natural alignment is
> from the *most* significant bit end?
>
> * DW_OP_piece: Some existing producers may emit DW_OP_piece operations
> that exceed the size of a single register, supposedly referring to
> multiple ("consecutive") registers.
>
> This usage is not covered by the current description of DW_OP_piece.
> Should it be?
>
> --
> Andreas
>
> _______________________________________________
> Dwarf-Discuss mailing list
> Dwarf-Discuss@lists.dwarfstd.org
> http://lists.dwarfstd.org/listinfo.cgi/dwarf-discuss-dwarfstd.org
>
--
Michael Eager eager(a)eagercon.com
1960 Park Blvd., Palo Alto, CA 94306 650-325-8077
next reply other threads:[~2016-12-01 19:32 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-01 19:32 Michael Eager [this message]
-- strict thread matches above, loose matches on Subject: below --
2016-12-06 18:56 Andreas Arnez
2016-12-01 17:40 Mark Wielaard
2016-12-01 14:17 Andreas Arnez
2016-12-01 14:04 Jakub Jelinek
2016-12-01 13:52 Robinson, Paul
2016-12-01 12:59 Todd Allen
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=58407AB5.9080308@eagercon.com \
--to=eager@eagercon.com \
--cc=elfutils-devel@lists.fedorahosted.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 read-only IMAP folder(s) and NNTP newsgroup(s).