Date: Sun, 6 Aug 2023 21:27:40 GMT From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 15876d9fd83f - main - sys/cdefs.h: fix for use __restrict in C++ Message-ID: <202308062127.376LRei9026246@gitrepo.freebsd.org>
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The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=15876d9fd83fdfa7d541ea747eb40faeade975d2 commit 15876d9fd83fdfa7d541ea747eb40faeade975d2 Author: Sebastian Huber <sebastian.huber@embedded-brains.de> AuthorDate: 2023-08-06 13:27:27 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2023-08-06 21:09:52 +0000 sys/cdefs.h: fix for use __restrict in C++ Newlib shares large parts of <sys/cdefs.h> with FreeBSD and received this bug report: https://sourceware.org/pipermail/newlib/2023/020400.html 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 Rewrite the logic in the header so that __restrict is kept alone when available. PR: 272723 MFC after: 1 week --- sys/sys/cdefs.h | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) diff --git a/sys/sys/cdefs.h b/sys/sys/cdefs.h index 1de042339c3a..797460c08db8 100644 --- a/sys/sys/cdefs.h +++ b/sys/sys/cdefs.h @@ -403,17 +403,15 @@ #endif /* - * 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. + * We use `__restrict' as a way to define the `restrict' type qualifier + * without disturbing older software that is unaware of C99 keywords. + * GCC also provides `__restrict' as an extension to support C99-style + * restricted pointers in other language modes. */ -#if !(__GNUC__ == 2 && __GNUC_MINOR__ == 95) -#if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 199901 -#define __restrict -#else +#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901 #define __restrict restrict -#endif +#elif !__GNUC_PREREQ__(2, 95) +#define __restrict #endif /*
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