From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.3 required=5.0 tests=MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 31274 invoked from network); 17 Apr 2021 00:00:28 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 17 Apr 2021 00:00:28 -0000 Received: (qmail 22304 invoked by uid 550); 17 Apr 2021 00:00:26 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 22285 invoked from network); 17 Apr 2021 00:00:25 -0000 Date: Fri, 16 Apr 2021 20:00:13 -0400 From: Rich Felker To: James Y Knight Cc: musl@lists.openwall.com, =?utf-8?B?w4lyaWNv?= Nogueira Message-ID: <20210417000012.GQ2546@brightrain.aerifal.cx> References: <20210416003521.2147-1-ericonr@disroot.org> <20210416003521.2147-2-ericonr@disroot.org> <20210416142658.GO2546@brightrain.aerifal.cx> <20210416185118.GP2546@brightrain.aerifal.cx> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Subject: Re: [musl] [PATCH 2/2] include in On Fri, Apr 16, 2021 at 06:12:52PM -0400, James Y Knight wrote: > Ugh, I thought Clang had added support for this years ago. But it looks > like the change (https://reviews.llvm.org/D34158) never actually made it > in; it ran into some test failures after being committed and was > reverted, and then never reapplied. :( The story of LLVM.. Random junk getting committed and kept, actually important and correct changes getting reverted because of bogus tests. Rich > On Fri, Apr 16, 2021 at 2:51 PM Rich Felker wrote: > > > On Fri, Apr 16, 2021 at 02:57:21PM -0300, Érico Nogueira wrote: > > > Em 16/04/2021 11:26, Rich Felker escreveu: > > > >On Thu, Apr 15, 2021 at 09:35:21PM -0300, Érico Nogueira wrote: > > > >>GCC source code does contain a function to pre-include the > > > >> header for glibc targets, but even so glibc still > > > > > > I seem to have been mistaken about the feature being glibc specific; > > using > > > > > > echo "" | cc -xc - -E > > > > > > it seems the file does end up being included automatically. > > > > > > However, when using clang instead of gcc, it isn't included > > > automatically. I don't know if this is something that clang ought to > > > fix, is there some sort of standard about ? Michael > > > Forney's cproc compiler doesn't seem to touch it either. > > > > It's not a standard, but given that it's established I don't see any > > reasonable argument for other compilers not to just do the same. You > > can always fix them manually with CC="clang -include stdc-predef.h" or > > similar though. > > > > > >>includes it in their own header. furthermore, even if GCC > > > >>implemented this for musl targets, it is still necessary for other > > > >>compilers or previous versions of GCC. > > > >>--- > > > >> include/features.h | 2 ++ > > > >> 1 file changed, 2 insertions(+) > > > >> > > > >>diff --git a/include/features.h b/include/features.h > > > >>index 85cfb72a..f3d53cbe 100644 > > > >>--- a/include/features.h > > > >>+++ b/include/features.h > > > >>@@ -1,6 +1,8 @@ > > > >> #ifndef _FEATURES_H > > > >> #define _FEATURES_H > > > >>+#include > > > >>+ > > > >> #if defined(_ALL_SOURCE) && !defined(_GNU_SOURCE) > > > >> #define _GNU_SOURCE 1 > > > >> #endif > > > >>-- > > > >>2.31.1 > > > > > > > >I've hesitated to do this because features.h is not consistently > > > >included from all standard headers (only if it's needed), and the > > > >result would be inconsistent exposure of these macros. (Also > > > >inconsistent if they're checked before any standard headers are > > > >included, which is unfixable.) I think it makes more sense to just add > > > >"-include stdc-predef.h" to the compiler specfile or equivalent if it > > > >doesn't auto-include it, so that you get behavior that actually > > > >matches the spec. > > > > > > Do you know if clang can use the specfile? That would make it worth > > > it adding the entry, since GCC has the expected behavior already. > > > > No; specfiles are highly tied to GCC's compiler driver architecture. > > clang might have some other equivalent mechanism though. > > > > Rich > >