Re: [Qemu-devel] [PULL v3 26/28] seccomp: Work-around GCC 4.x bug in gnu99 mode

[Eduardo Otubo <otubo@redhat.com>]

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On 17/01/2019 - 14:38:12, Thomas Huth wrote:
> We'd like to compile QEMU with -std=gnu99, but GCC 4.8 currently
> fails to compile qemu-seccomp.c in this mode:
> 
> qemu-seccomp.c:45:1: error: initializer element is not constant
>  };
>  ^
> qemu-seccomp.c:45:1: error: (near initialization for ‘sched_setscheduler_arg[0]’)
> 
> This is due to a compiler bug which has just been fixed in GCC 5.0:
> 
>  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63567
> 
> Since we still want to support GCC 4.8 for a while and also want to use
> gnu99 mode, work-around the issue by expanding the macro manually.
> 
> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  qemu-seccomp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/qemu-seccomp.c b/qemu-seccomp.c
> index 5c73e6a..36d5829 100644
> --- a/qemu-seccomp.c
> +++ b/qemu-seccomp.c
> @@ -41,7 +41,8 @@ struct QemuSeccompSyscall {
>  };
>  
>  const struct scmp_arg_cmp sched_setscheduler_arg[] = {
> -    SCMP_A1(SCMP_CMP_NE, SCHED_IDLE)
> +    /* was SCMP_A1(SCMP_CMP_NE, SCHED_IDLE), but expanded due to GCC 4.x bug */
> +    { .arg = 1, .op = SCMP_CMP_NE, .datum_a = SCHED_IDLE }
>  };
>  
>  static const struct QemuSeccompSyscall blacklist[] = {
> -- 
> 1.8.3.1
> 
> 

Just noticed you already sent the pull request, sorry, my tree was outdated.
Please ignore my previous email :)

-- 
Eduardo Otubo

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