From: Pedro Alves <palves@redhat.com>
To: Jakub Jelinek <jakub@redhat.com>, Nick Clifton <nickc@redhat.com>
Cc: Jason Merrill <jason@redhat.com>,
Ian Lance Taylor <iant@google.com>,
Richard Biener <richard.guenther@gmail.com>,
matz@gcc.gnu.org, Scott Gayou <sgayou@redhat.com>,
Tom Tromey <tom@tromey.com>,
gcc-patches List <gcc-patches@gcc.gnu.org>,
Binutils <binutils@sourceware.org>,
GDB Patches <gdb-patches@sourceware.org>
Subject: Re: RFC: libiberty PATCH to disable demangling of ancient mangling schemes
Date: Fri, 07 Dec 2018 16:11:00 -0000 [thread overview]
Message-ID: <aff87924-f257-733c-cb6c-0b45dd1a9684@redhat.com> (raw)
In-Reply-To: <20181207104011.GD12380@tucnak>
Adding gdb-patches, since demangling affects gdb.
Ref: https://gcc.gnu.org/ml/gcc-patches/2018-12/msg00407.html
On 12/07/2018 10:40 AM, Jakub Jelinek wrote:
> On Fri, Dec 07, 2018 at 10:27:17AM +0000, Nick Clifton wrote:
>>>> Looks good to me. Independently, do you see a reason not to disable the
>>>> old demangler entirely?
>>>
>>> Like so. Does anyone object to this? These mangling schemes haven't
>>> been relevant in decades.
>>
>> I am not really familiar with this old scheme, so please excuse my ignorance
>> in asking these questions:
>>
>> * How likely is it that there are old toolchain in use out there that still
>> use the v2 mangling ? Ie I guess that I am asking "which generation(s)
>> of gcc used v2 mangling ?"
>
> GCC 3.0 and up used the new (Itanium C++ ABI) mangling, 2.95 and older used the old
> mangling (2.96-RH used the new mangling I believe).
> So you need compiler older than 17.5 years to have the old mangling.
> Such a compiler didn't support most of the contemporarily used platforms
> though at all (e.g. x86-64, powerpc64le, aarch64, I believe not even
> powerpc64-linux).
>
Yeah.
I guess the question would be whether it is reasonable to expect
that people will still need to debug&inspect (with gdb, c++filt, etc.)
any such old binary, and that they will need to do it with with modern
tools, as opposed to sticking with older binutils&gdb, and how often
would that be needed.
I would say that it's very, very unlikely, and not worth it of the
maintenance burden.
Last I heard of 2.95-produced binaries I think was for some ancient gcc-2.95-based
cross compiler that was still being minimally maintained, because it was needed
to build&maintain some legacy stuff. That was maybe over 8 years ago, and
it was off trunk. It's probably dead by now. And if isn't dead,
whoever maintains the compiler off trunk certainly can also maintain old-ish
binutils & gdb off trunk.
Thanks,
Pedro Alves
next prev parent reply other threads:[~2018-12-07 16:11 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-30 8:38 RFA/RFC: Add stack recursion limit to libiberty's demangler Nick Clifton
2018-11-30 8:42 ` Jakub Jelinek
2018-11-30 10:27 ` Nick Clifton
2018-11-30 13:46 ` Michael Matz
2018-11-30 14:57 ` Ian Lance Taylor
2018-12-02 0:49 ` Cary Coutant
2018-12-03 14:53 ` Nick Clifton
2018-12-03 22:00 ` Joseph Myers
2018-11-30 13:56 ` Ian Lance Taylor
2018-11-30 14:03 ` Jakub Jelinek
2018-11-30 17:41 ` RFA/RFC: Add stack recursion limit to libiberty's demangler [v3] Nick Clifton
2018-11-30 17:49 ` Jakub Jelinek
2018-11-30 18:19 ` Pedro Alves
2018-12-03 10:28 ` Richard Biener
2018-12-03 14:45 ` Nick Clifton
2018-12-03 18:49 ` Ian Lance Taylor via gcc-patches
2018-12-04 14:00 ` RFA/RFC: Add stack recursion limit to libiberty's demangler [v4] Nick Clifton
2018-12-04 15:02 ` Pedro Alves
2018-12-04 16:57 ` RFA/RFC: Add stack recursion limit to libiberty's demangler [v5] Nick Clifton
2018-12-04 17:08 ` Pedro Alves
2018-12-06 11:12 ` Nick Clifton
2018-12-06 18:04 ` Ian Lance Taylor via gcc-patches
2018-12-07 16:17 ` H.J. Lu
2018-12-07 16:25 ` [PATCH] Set DEMANGLE_RECURSION_LIMIT to 1536 H.J. Lu
2018-12-10 14:52 ` Michael Matz
2018-12-10 15:10 ` Jakub Jelinek
2018-12-10 15:34 ` Jason Merrill
2018-12-11 0:33 ` Jeff Law
2018-12-11 6:58 ` Jakub Jelinek
2018-12-11 11:05 ` Pedro Alves
2018-12-11 14:26 ` Ian Lance Taylor via gcc-patches
2018-12-11 15:07 ` Pedro Alves
2018-12-11 10:34 ` Pedro Alves
2018-12-10 15:12 ` Nick Clifton
2018-12-10 15:18 ` Jakub Jelinek
2018-12-10 15:26 ` Nick Clifton
2018-12-10 15:35 ` Jakub Jelinek
2018-12-10 18:20 ` Ian Lance Taylor via gcc-patches
2018-12-10 18:55 ` Jakub Jelinek
2018-12-10 23:47 ` Jason Merrill
2018-12-10 15:18 ` David Malcolm
2018-12-10 15:31 ` Nick Clifton
2018-12-06 16:14 ` RFA/RFC: Add stack recursion limit to libiberty's demangler [v5] Jason Merrill
2018-12-06 21:22 ` RFC: libiberty PATCH to disable demangling of ancient mangling schemes Jason Merrill
2018-12-07 10:27 ` Nick Clifton
2018-12-07 10:40 ` Jakub Jelinek
2018-12-07 16:11 ` Pedro Alves [this message]
2018-12-07 17:49 ` Tom Tromey
2018-12-07 21:00 ` Jason Merrill
2018-12-14 22:39 ` Jason Merrill
2018-12-16 4:50 ` Simon Marchi
2018-12-07 16:28 ` Nick Clifton
2018-12-07 11:37 ` Richard Biener
2018-12-07 15:49 ` Jason Merrill
2018-12-10 1:04 ` Eric Gallager
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=aff87924-f257-733c-cb6c-0b45dd1a9684@redhat.com \
--to=palves@redhat.com \
--cc=binutils@sourceware.org \
--cc=gcc-patches@gcc.gnu.org \
--cc=gdb-patches@sourceware.org \
--cc=iant@google.com \
--cc=jakub@redhat.com \
--cc=jason@redhat.com \
--cc=matz@gcc.gnu.org \
--cc=nickc@redhat.com \
--cc=richard.guenther@gmail.com \
--cc=sgayou@redhat.com \
--cc=tom@tromey.com \
/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).