From: Corinna Vinschen <vinschen@redhat.com>
To: Sebastian Huber <sebastian.huber@embedded-brains.de>
Cc: Bruno De Fraine <Bruno.DeFraine@synopsys.com>,
"newlib@sourceware.org" <newlib@sourceware.org>
Subject: Re: newlib header breaks restricted pointers in C++
Date: Tue, 25 Jul 2023 20:48:35 +0200 [thread overview]
Message-ID: <ZMAZA1r+fNty6/BK@calimero.vinschen.de> (raw)
In-Reply-To: <3126b987-ca19-97f6-9c7a-06243add9354@embedded-brains.de>
On Jul 25 19:46, Sebastian Huber wrote:
> On 25.07.23 19:35, Corinna Vinschen wrote:
> > Hi Bruno,
> >
> > On Jul 24 22:23, Bruno De Fraine wrote:
> > > Hello,
> > >
> > > As an extension, GCC and clang offer C99-style restricted pointers in C++ mode:
> > > https://gcc.gnu.org/onlinedocs/gcc/Restricted-Pointers.html
> > >
> > > We notice that this extension is broken when including newlib headers: restricted pointers are treated as ordinary pointers.
> > >
> > > We traced this to the following section of newlib/libc/include/sys/cdefs.h:
> > >
> > > /*
> > > * GCC 2.95 provides `__restrict' as an extension to C90 to support the
> > > * C99-specific `restrict' type qualifier. We happen to use `__restrict' as
> > > * a way to define the `restrict' type qualifier without disturbing older
> > > * software that is unaware of C99 keywords.
> > > */
> > > #if !(__GNUC__ == 2 && __GNUC_MINOR__ == 95)
> > > #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 199901
> > > #define __restrict
> > > #else
> > > #define __restrict restrict
> > > #endif
> > > #endif
> > >
> > > While the GCC __restrict extension was indeed introduced in GCC 2.95, it is not limited to this version; the extension is also not limited to C90:
> > > https://gcc.gnu.org/gcc-2.95/c++features.html
> > Either way, the above has been taken from FreeBSD, and it is still,
> > as of today, the same expression as used in FreeBSDs sys/cdefs.h
> > file.
> >
> > Seb, any input on this?
>
> I added a FreeBSD bug report:
>
> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=272723
Great, thanks! Do we want to wait for a FreeBSD solution, or do
we want to change it now and, maybe, take the FreeBSD version later?
Does anybody want to provide a git compatible patch?
Thanks,
Corinna
next prev parent reply other threads:[~2023-07-25 18:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-24 22:23 Bruno De Fraine
2023-07-25 17:35 ` Corinna Vinschen
2023-07-25 17:46 ` Sebastian Huber
2023-07-25 18:48 ` Corinna Vinschen [this message]
2023-07-25 23:48 ` Steven J Abner
2023-07-27 9:00 ` Corinna Vinschen
2023-07-28 14:15 ` Sebastian Huber
2023-07-28 14:42 ` Joel Sherrill
2023-07-31 11:04 ` Bruno De Fraine
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