Re: [PATCH v2 08/13] compiler.h: explicit case for Clang printf attribute

[Peter Maydell]

On Thu, 26 Nov 2020 at 11:30, <marcandre.lureau@redhat.com> wrote:
>
> From: Marc-André Lureau <marcandre.lureau@redhat.com>
>
> Since commit efc6c07 ("configure: Add a test for the minimum compiler
> version"), QEMU explicitely depends on GCC >= 4.8, we could thus drop
> earlier version checks. Except clang advertizes itself as GCC 4.2.1.
>
> Since clang doesn't support gnu_printf, make that case explicitely and
> drop GCC version check.
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  include/qemu/compiler.h | 22 ++++++++++------------
>  1 file changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h
> index ae3e0df34c..108bfdb391 100644
> --- a/include/qemu/compiler.h
> +++ b/include/qemu/compiler.h
> @@ -90,18 +90,16 @@
>  #define QEMU_BUILD_BUG_ON_ZERO(x) (sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)) - \
>                                     sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)))
>
> -#if defined __GNUC__
> -# if !G_GNUC_CHECK_VERSION(4, 4)
> -   /* gcc versions before 4.4.x don't support gnu_printf, so use printf. */
> -#  define GCC_FMT_ATTR(n, m) __attribute__((format(printf, n, m)))
> -# else
> -   /* Use gnu_printf when supported (qemu uses standard format strings). */
> -#  define GCC_FMT_ATTR(n, m) __attribute__((format(gnu_printf, n, m)))
> -#  if defined(_WIN32)
> -    /* Map __printf__ to __gnu_printf__ because we want standard format 
> strings
> -     * even when MinGW or GLib include files use __printf__. */
> -#   define __printf__ __gnu_printf__
> -#  endif
> +#if defined(__clang__)
> +  /* clang doesn't support gnu_printf, so use printf. */
> +# define GCC_FMT_ATTR(n, m) __attribute__((format(printf, n, m)))
> +#elif defined(__GNUC__)
> +   /* Use gnu_printf (qemu uses standard format strings). */
> +# define GCC_FMT_ATTR(n, m) __attribute__((format(gnu_printf, n, m)))
> +# if defined(_WIN32)
> +   /* Map __printf__ to __gnu_printf__ because we want standard format 
> strings
> +    * even when MinGW or GLib include files use __printf__. */
> +#  define __printf__ __gnu_printf__
>  # endif

checkpatch probably warns about the block comment style so you might
as well fix it while touching that line, but otherwise
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM