From: "vvvvvv at google dot com" <sourceware-bugzilla@sourceware.org>
To: elfutils-devel@sourceware.org
Subject: [Bug libdw/30967] Discriminator in Dwarf_Line_s may exceed 24 bits
Date: Thu, 26 Oct 2023 15:37:38 +0000 [thread overview]
Message-ID: <bug-30967-10460-BrMpdAZzqn@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-30967-10460@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=30967
--- Comment #9 from Aleksei Vetrov <vvvvvv at google dot com> ---
(In reply to Frank Ch. Eigler from comment #7)
> So my preferred workaround:
I like this workaround and it works in our use case.
> appears to be based on the assumption that truncated bitfields will not
> collide. Has this assumption been tested?
No such assumption can be made, there is no guarantees from DWARF standard and
it is possible to manually generate DWARF with discriminators exceeding even
"unsigned int": just use any library and shift all values by 32 bits. It will
be
well within standard, however compilers are not expected to behave like this.
In an "liblog.so" attachment truncated values don't collide.
I'm more interested in this: what is worst that can happen on discriminator
collision? We are not using discriminator at all in ABI monitoring, so I'm not
familiar with its use cases.
--
You are receiving this mail because:
You are on the CC list for the bug.
next prev parent reply other threads:[~2023-10-26 15:37 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-12 13:30 [Bug libdw/30967] New: " vvvvvv at google dot com
2023-10-12 14:12 ` [Bug libdw/30967] " vvvvvv at google dot com
2023-10-12 14:30 ` mark at klomp dot org
2023-10-25 15:47 ` fche at redhat dot com
2023-10-26 11:19 ` vvvvvv at google dot com
2023-10-26 11:32 ` mark at klomp dot org
2023-10-26 14:55 ` mark at klomp dot org
2023-10-26 15:12 ` fche at redhat dot com
2023-10-26 15:30 ` fche at redhat dot com
2023-10-26 15:37 ` vvvvvv at google dot com [this message]
2023-10-26 15:46 ` mark at klomp dot org
2023-10-26 15:47 ` fche at redhat dot com
2023-10-31 16:57 ` vvvvvv at google dot com
2023-10-31 23:19 ` mark at klomp dot org
2023-10-31 23:19 ` mark at klomp dot org
2023-11-07 19:01 ` vvvvvv at google dot com
2023-11-07 19:11 ` vvvvvv at google dot com
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=bug-30967-10460-BrMpdAZzqn@http.sourceware.org/bugzilla/ \
--to=sourceware-bugzilla@sourceware.org \
--cc=elfutils-devel@sourceware.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).