From: Jeff King <peff@peff.net>
To: Stephan Beyer <s-beyer@gmx.net>
Cc: "Junio C Hamano" <gitster@pobox.com>,
"René Scharfe" <l.s.r@web.de>, "Paul Tan" <pyokagan@gmail.com>,
"brian m. carlson" <sandals@crustytoothpaste.net>,
"Johannes Schindelin" <Johannes.Schindelin@gmx.de>,
git@vger.kernel.org
Subject: Re: [PATCH] Fix maybe-uninitialized warnings found by gcc 9 -flto
Date: Thu, 5 Sep 2019 18:48:59 -0400 [thread overview]
Message-ID: <20190905224859.GA28660@sigill.intra.peff.net> (raw)
In-Reply-To: <20190905082459.26816-1-s-beyer@gmx.net>
On Thu, Sep 05, 2019 at 10:24:59AM +0200, Stephan Beyer wrote:
> Compiler heuristics for detection of potentially uninitialized variables
> may change between compiler versions and enabling link-time optimization
> may find new warnings. Indeed, compiling with gcc 9.2.1 and enabled
> link-time optimization feature resulted in a few hits that are fixed by
> this patch in the most naïve way. This allows to compile git using the
> DEVELOPER=1 switch (which sets -Werror) and using the -flto flag.
Lots of discussion in this thread. Let's try to turn it into some
patches. :)
After the patches below, I can compile cleanly with gcc 9.2.1 using
-flto with both -O2 and -O3 (some of the cases only seemed to trigger
for me with -O3).
I've ordered them in decreasing value. The first one is a real bugfix,
the second is a related cleanup. The next 3 are appeasing the compiler,
but I think are a good idea (but note I went more for root causes than
your originals). The last one is perhaps more controversial, but IMHO
worth doing.
[1/6]: git-am: handle missing "author" when parsing commit
[2/6]: pack-objects: use object_id in packlist_alloc()
[3/6]: bulk-checkin: zero-initialize hashfile_checkpoint
[4/6]: diff-delta: set size out-parameter to 0 for NULL delta
[5/6]: test-read-cache: drop namelen variable
[6/6]: pack-objects: drop packlist index_pos optimization
builtin/am.c | 4 +++-
builtin/pack-objects.c | 33 ++++++++++++++-------------------
bulk-checkin.c | 2 +-
diff-delta.c | 2 ++
pack-bitmap-write.c | 2 +-
pack-bitmap.c | 2 +-
pack-objects.c | 20 ++++++++++----------
pack-objects.h | 6 ++----
t/helper/test-read-cache.c | 5 ++---
9 files changed, 36 insertions(+), 40 deletions(-)
-Peff
next prev parent reply other threads:[~2019-09-05 22:49 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-05 8:24 [PATCH] Fix maybe-uninitialized warnings found by gcc 9 -flto Stephan Beyer
2019-09-05 17:08 ` René Scharfe
2019-09-05 17:53 ` Jeff King
2019-09-05 19:09 ` René Scharfe
2019-09-05 19:25 ` Junio C Hamano
2019-09-05 19:39 ` René Scharfe
2019-09-05 19:50 ` Junio C Hamano
2019-09-05 17:41 ` Junio C Hamano
2019-09-05 17:56 ` Junio C Hamano
2019-09-05 18:03 ` Jeff King
2019-09-05 18:22 ` Junio C Hamano
2019-09-05 22:48 ` Jeff King [this message]
2019-09-05 22:50 ` [PATCH 1/6] git-am: handle missing "author" when parsing commit Jeff King
2019-09-05 22:52 ` [PATCH 2/6] pack-objects: use object_id in packlist_alloc() Jeff King
2019-09-05 22:52 ` [PATCH 3/6] bulk-checkin: zero-initialize hashfile_checkpoint Jeff King
2019-09-05 22:53 ` [PATCH 4/6] diff-delta: set size out-parameter to 0 for NULL delta Jeff King
2019-09-05 22:53 ` [PATCH] Fix maybe-uninitialized warnings found by gcc 9 -flto Stephan Beyer
2019-09-05 22:58 ` Jeff King
2019-09-05 23:10 ` Stephan Beyer
2019-09-06 1:24 ` Jeff King
2019-09-06 1:36 ` [PATCH v2 6/6] pack-objects: drop packlist index_pos optimization Jeff King
2019-09-05 22:54 ` [PATCH 5/6] test-read-cache: drop namelen variable Jeff King
2019-09-05 22:56 ` [PATCH 6/6] pack-objects: drop packlist index_pos optimization Jeff King
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
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190905224859.GA28660@sigill.intra.peff.net \
--to=peff@peff.net \
--cc=Johannes.Schindelin@gmx.de \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=l.s.r@web.de \
--cc=pyokagan@gmail.com \
--cc=s-beyer@gmx.net \
--cc=sandals@crustytoothpaste.net \
/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.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
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).