[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH 1/3] configure: Fix atomic64 test for --enable-werror on macO
From: |
Christian Schoenebeck |
Subject: |
Re: [PATCH 1/3] configure: Fix atomic64 test for --enable-werror on macOS |
Date: |
Fri, 24 Jul 2020 17:01:59 +0200 |
On Freitag, 24. Juli 2020 16:32:18 CEST Thomas Huth wrote:
> When using --enable-werror for the macOS builders in the Cirrus-CI,
> the atomic64 test is currently failing, and config.log shows a bunch
> of error messages like this:
>
> config-temp/qemu-conf.c:6:7: error: implicit declaration of function
> '__atomic_load_8' is invalid in C99
> [-Werror,-Wimplicit-function-declaration] y = __atomic_load_8(&x, 0);
> ^
> config-temp/qemu-conf.c:6:7: error: this function declaration is not a
> prototype [-Werror,-Wstrict-prototypes]
>
> Seems like these __atomic_*_8 functions are available in one of the
> libraries there, so that the test links and passes there when not
> using --enable-werror. But there does not seem to be a valid prototype
> for them in any of the header files, so that the test fails when using
> --enable-werror.
>
> Fix it by using the "official" built-in functions instead (see e.g.
> https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html).
> We are not using the *_8 variants in QEMU anyway.
>
> Suggested-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
> configure | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/configure b/configure
> index 4bd80ed507..9eaf501f50 100755
> --- a/configure
> +++ b/configure
> @@ -5919,11 +5919,11 @@ int main(void)
> {
> uint64_t x = 0, y = 0;
> #ifdef __ATOMIC_RELAXED
> - y = __atomic_load_8(&x, 0);
> - __atomic_store_8(&x, y, 0);
> - __atomic_compare_exchange_8(&x, &y, x, 0, 0, 0);
> - __atomic_exchange_8(&x, y, 0);
> - __atomic_fetch_add_8(&x, y, 0);
> + y = __atomic_load_n(&x, __ATOMIC_RELAXED);
> + __atomic_store_n(&x, y, __ATOMIC_RELAXED);
> + __atomic_compare_exchange_n(&x, &y, x, 0, __ATOMIC_RELAXED,
> __ATOMIC_RELAXED); + __atomic_exchange_n(&x, y, __ATOMIC_RELAXED);
Ah right, there is also the __atomic_*_n() variant of these functions. I
actually had the more generic variants in mind.
But LGTM and yes, it resolves the warnings on macOS, so ...
Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> + __atomic_fetch_add(&x, y, __ATOMIC_RELAXED);
> #else
> typedef char is_host64[sizeof(void *) >= sizeof(uint64_t) ? 1 : -1];
> __sync_lock_test_and_set(&x, y);
Best regards,
Christian Schoenebeck
signature.asc
Description: This is a digitally signed message part.
- Re: [PATCH 2/3] cirrus.yml: Compile macOS and FreeBSD with -Werror, (continued)
- Re: [PATCH 2/3] cirrus.yml: Compile macOS and FreeBSD with -Werror, Thomas Huth, 2020/07/27
- Re: [PATCH 2/3] cirrus.yml: Compile macOS and FreeBSD with -Werror, Peter Maydell, 2020/07/24
- Re: [PATCH 2/3] cirrus.yml: Compile macOS and FreeBSD with -Werror, Christian Schoenebeck, 2020/07/24
- Re: [PATCH 2/3] cirrus.yml: Compile macOS and FreeBSD with -Werror, Daniel P . Berrangé, 2020/07/27
- Re: [PATCH 2/3] cirrus.yml: Compile macOS and FreeBSD with -Werror, Thomas Huth, 2020/07/28
Re: [PATCH 2/3] cirrus.yml: Compile macOS and FreeBSD with -Werror, Peter Maydell, 2020/07/24
Re: [PATCH 2/3] cirrus.yml: Compile macOS and FreeBSD with -Werror, Ed Maste, 2020/07/26
[PATCH 1/3] configure: Fix atomic64 test for --enable-werror on macOS, Thomas Huth, 2020/07/24
[PATCH 3/3] cirrus.yml: Update the macOS jobs to Catalina, Thomas Huth, 2020/07/24