From: Florian Weimer <fw@deneb.enyo.de>
To: David Malcolm <dmalcolm@redhat.com>
Cc: Andrea Corallo <Andrea.Corallo@arm.com>,
"gcc-patches\@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
"jit\@gcc.gnu.org" <jit@gcc.gnu.org>, nd <nd@arm.com>
Subject: Re: [PATCH][gcc] libgccjit: introduce version entry points
Date: Wed, 01 Jan 2020 00:00:00 -0000 [thread overview]
Message-ID: <87v9nh3o89.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <e8d7ce1feaada9ec28886d4870da37e0a3a7c15a.camel@redhat.com> (David Malcolm's message of "Thu, 05 Mar 2020 21:34:53 -0500")
* David Malcolm:
>
> My first thought here was that we should have a way to get all three at
> once, but it turns out that parse_basever does its own caching
> internally.
>
> I don't think the current implementation is thread-safe; parse_basever
> has:
>
> static int s_major = -1, s_minor, s_patchlevel;
>
> if (s_major == -1)
> if (sscanf (BASEVER, "%d.%d.%d", &s_major, &s_minor, &s_patchlevel) != 3)
> {
> sscanf (BASEVER, "%d.%d", &s_major, &s_minor);
> s_patchlevel = 0;
> }
>
> I think there's a race here:
Right, it's not thread-safe.
One possiblity would be to store all three numbers in one unsigned
int, and used relaxed MO loads and stores. A zero value would
indicate that initialization is needed.
It will break if there are ever more than 1000 or so GCC releases, but
it will be good for a while.
next prev parent reply other threads:[~2020-03-06 8:04 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-01 0:00 Andrea Corallo
2020-01-01 0:00 ` David Malcolm
2020-01-01 0:00 ` David Malcolm
2020-03-08 14:08 ` Andrea Corallo
2020-01-01 0:00 ` Andrea Corallo
2020-01-01 0:00 ` Florian Weimer [this message]
2020-03-18 22:51 ` [PATCH V3][gcc] " Andrea Corallo
2020-03-21 1:32 ` David Malcolm
2020-03-23 13:03 ` Richard Biener
2020-03-29 20:31 ` Andrea Corallo
2020-03-30 16:09 ` David Malcolm
2020-03-31 1:13 ` David Malcolm
2020-03-31 8:03 ` Andrea Corallo
2020-03-31 12:05 ` [PATCH V4][gcc] " Andrea Corallo
2020-03-31 17:33 ` David Malcolm
2020-03-31 19:00 ` Andrea Corallo
-- strict thread matches above, loose matches on Subject: below --
2020-01-01 0:00 [PATCH][gcc] " Andrea Corallo
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