Re: [PATCH 2/2] qom/object: Remove pre-C11 check

[Markus Armbruster <armbru@xxxxxxxxxx>]

Philippe Mathieu-Daudé <philmd@xxxxxxxxxxxxxxxx> writes:

> We mandate a compiler supporting C11 since 2021-06-15 in
> commit d22797ce36a ("configure: Use -std=gnu11"), thus the
> max_align_t type definition exists. Remove what is now dead
> code.
>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxxxxxxxx>

> ---
>  qom/object.c | 14 +-------------
>  1 file changed, 1 insertion(+), 13 deletions(-)
>
> diff --git a/qom/object.c b/qom/object.c
> index 0ac201de4c1..f79b2cf3618 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -675,18 +675,6 @@ static void object_finalize(void *data)
>      }
>  }
>  
> -/* Find the minimum alignment guaranteed by the system malloc. */
> -#if __STDC_VERSION__ >= 201112L
> -typedef max_align_t qemu_max_align_t;
> -#else
> -typedef union {
> -    long l;
> -    void *p;
> -    double d;
> -    long double ld;
> -} qemu_max_align_t;
> -#endif
> -
>  static Object *object_new_with_type(Type type)
>  {
>      Object *obj;
> @@ -703,7 +691,7 @@ static Object *object_new_with_type(Type type)
>       * Do not use qemu_memalign unless required.  Depending on the
>       * implementation, extra alignment implies extra overhead.
>       */
> -    if (likely(align <= __alignof__(qemu_max_align_t))) {
> +    if (likely(align <= __alignof__(max_align_t))) {
>          obj = g_malloc(size);
>          obj_free = g_free;
>      } else {
           obj = qemu_memalign(align, size);
           obj_free = qemu_vfree;
       }

Reviewed-by: Markus Armbruster <armbru@xxxxxxxxxx>

Context leads me to qemu_try_memalign() via qemu_memalign():

   #elif defined(CONFIG_ALIGNED_MALLOC)
       ptr = _aligned_malloc(size, alignment);
   #elif defined(CONFIG_VALLOC)
       ptr = valloc(size);
   #elif defined(CONFIG_MEMALIGN)
       ptr = memalign(alignment, size);
   #else
       #error No function to allocate aligned memory available
   #endif

C11 provides aligned_alloc().