diff options
| author | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2023-08-06 16:27:27 +0300 |
|---|---|---|
| committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2023-08-07 14:45:21 +0300 |
| commit | 3c75fac130b5720068707f67b12f4372abf4ad38 (patch) | |
| tree | 1d9690822a760212ae8cc547bf28b2589711cbd0 /newlib | |
| parent | b12934540f17ba7c22923940e48bfbf02d0ae082 (diff) | |
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
Diffstat (limited to 'newlib')
| -rw-r--r-- | newlib/libc/include/sys/cdefs.h | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/newlib/libc/include/sys/cdefs.h b/newlib/libc/include/sys/cdefs.h index 808498c50..cc1a8a1cc 100644 --- a/newlib/libc/include/sys/cdefs.h +++ b/newlib/libc/include/sys/cdefs.h @@ -412,17 +412,15 @@ #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 /* |