From: Tom Tromey <tom@tromey.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: Tom Tromey <tromey@adacore.com>,
gdb-patches@sourceware.org, Pedro Alves <palves@redhat.com>
Subject: Re: [PATCH 2/3] Consistently use BFD's time
Date: Thu, 18 Jun 2020 08:14:18 -0600 [thread overview]
Message-ID: <87k1044g1x.fsf@tromey.com> (raw)
In-Reply-To: <83wo9s4sac.fsf@gnu.org> (Eli Zaretskii's message of "Wed, 15 Jan 2020 18:07:39 +0200")
>>>>> "Eli" == Eli Zaretskii <eliz@gnu.org> writes:
>> From: Tom Tromey <tromey@adacore.com>
>> Cc: Tom Tromey <tromey@adacore.com>
>> Date: Tue, 14 Jan 2020 14:09:55 -0700
>>
>> gdb uses the gnulib stat, while BFD does not. This can lead to
>> inconsistencies between the two, because the gnulib stat adjusts for
>> timezones.
Eli> There's one more potential issue with Gnulib's replacement of 'fstat':
Eli> it also replaces the definition of 'struct stat', and it does that in
Eli> a way that might yield incompatibility between the definition on
Eli> <sys/stat.h> the system header and Gnulib's sys/stat.h replacement.
I am looking into this issue again for the upcoming gdb 10 release.
Looking at the gnulib in the gdb tree, as far as I can tell, it doesn't
actually override struct stat. The code is all there:
/* Optionally, override 'struct stat' on native Windows. */
#if @GNULIB_OVERRIDES_STRUCT_STAT@
[...]
... however, this is only ever set to 0 in our tree:
$ git grep 'GNULIB_OVERRIDES_STRUCT_STAT.*=' -- gnulib/import/
gnulib/import/Makefile.in:GNULIB_OVERRIDES_STRUCT_STAT = @GNULIB_OVERRIDES_STRUCT_STAT@
gnulib/import/m4/sys_stat_h.m4: GNULIB_OVERRIDES_STRUCT_STAT=0; AC_SUBST([GNULIB_OVERRIDES_STRUCT_STAT])
(I chose a tighter grep for the purposes of posting, but in reality I
looked at all mentions of GNULIB_OVERRIDES_STRUCT_STAT.)
So, I think this is maybe not an issue.
The timezone thing, however, remains an issue. It seems dangerous to me
that we would have two implementations of stat that would give different
answers. It's too easy, IMO, to accidentally compare values from one
with values from the other -- in fact, that's what lead to the patches
in this thread I'm replying to.
Based on this, my inclination is to patch our copy of gnulib to avoid
replacing stat on Windows. I'm looking into how to do this.
Much of the rest of this series will still be needed. In particular it
unearths a real race in the BFD cache.
Let me know what you think.
Tom
next prev parent reply other threads:[~2020-06-18 14:14 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 21:10 [PATCH 0/3] Fix gdb's BFD cache Tom Tromey
2020-01-14 21:10 ` [PATCH 2/3] Consistently use BFD's time Tom Tromey
2020-01-14 23:17 ` Christian Biesinger via gdb-patches
2020-01-15 17:51 ` Eli Zaretskii
2020-01-16 20:47 ` Pedro Alves
2020-01-16 21:58 ` Christian Biesinger via gdb-patches
2020-01-16 22:31 ` Pedro Alves
2020-01-17 8:48 ` Eli Zaretskii
2020-01-17 18:32 ` Tom Tromey
2020-01-17 21:03 ` Tom Tromey
2020-01-18 11:07 ` Eli Zaretskii
2020-01-20 15:52 ` Pedro Alves
2020-01-20 15:53 ` Pedro Alves
2020-01-20 20:50 ` Eli Zaretskii
2020-01-20 20:58 ` Pedro Alves
2020-01-21 15:50 ` Pedro Alves
2020-01-21 19:38 ` Eli Zaretskii
2020-01-21 17:56 ` Eli Zaretskii
2020-01-23 22:05 ` Tom Tromey
2020-06-19 17:51 ` Tom Tromey
2020-04-01 20:20 ` Tom Tromey
2020-06-18 14:14 ` Tom Tromey [this message]
2020-06-18 15:04 ` Eli Zaretskii
2020-06-18 16:00 ` Tom Tromey
2020-06-18 17:27 ` Eli Zaretskii
2020-06-18 17:32 ` Pedro Alves
2020-06-18 17:54 ` Eli Zaretskii
2020-06-19 12:02 ` Pedro Alves
2020-06-19 12:13 ` Eli Zaretskii
2020-06-19 17:09 ` Tom Tromey
2020-06-19 20:24 ` Tom Tromey
2020-06-19 23:05 ` Pedro Alves
2020-07-21 19:39 ` Tom Tromey
2020-07-28 19:31 ` Tom Tromey
2020-08-13 12:15 ` Tom de Vries
2020-08-14 23:40 ` Joel Brobecker
2020-08-23 16:09 ` Joel Brobecker
2020-08-23 23:32 ` Pedro Alves
2020-08-24 20:04 ` Joel Brobecker
2020-09-02 14:45 ` Tom Tromey
2020-09-02 14:59 ` Joel Brobecker
2020-06-18 17:57 ` Tom Tromey
2020-01-14 21:10 ` [PATCH 1/3] Avoid hash table corruption in gdb_bfd.c Tom Tromey
2020-01-14 22:26 ` Christian Biesinger via gdb-patches
2020-01-14 22:13 ` [PATCH 3/3] Further simplify gdb BFD caching Tom Tromey
2020-01-23 22:30 ` Tom Tromey
2020-09-02 18:45 ` Tom Tromey
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=87k1044g1x.fsf@tromey.com \
--to=tom@tromey.com \
--cc=eliz@gnu.org \
--cc=gdb-patches@sourceware.org \
--cc=palves@redhat.com \
--cc=tromey@adacore.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