Re: [PATCH] f2fs: Disable gcc9 -Waddress-of-packed-member

[Daniel Kiper]

Neil, could you test this patch?

On Wed, May 29, 2019 at 08:34:55AM +0200, John Paul Adrian Glaubitz wrote:
> Disable the -Wadress-of-packaed-member diagnostic for the grub_f2fs_label
> function since the result is found to be false postive.
>
> A pointer to the 'volume_name' member of 'struct grub_f2fs_superblock' is
> guaranteed to be aligned as the offset of 'volume_name' within the struct
> is dividable by the natural alignment on both 32- and 64-bit targets.
>
> grub-core/fs/f2fs.c: In function ‘grub_f2fs_label’:
> grub-core/fs/f2fs.c:1253:60: error: taking address of packed member of 
> ‘struct grub_f2fs_superblock’ may result in an unaligned pointer value 
> [-Werror=address-of-packed-member]
>  1253 |     *label = (char *) grub_f2fs_utf16_to_utf8 
> (data->sblock.volume_name);
>       |                                                
> ~~~~~~~~~~~~^~~~~~~~~~~~
> cc1: all warnings being treated as errors
>
> Signed-off-by: John Paul Adrian Glaubitz <address@hidden>
> ---
>  grub-core/fs/f2fs.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/grub-core/fs/f2fs.c b/grub-core/fs/f2fs.c
> index bb28b291b..8a9992ca9 100644
> --- a/grub-core/fs/f2fs.c
> +++ b/grub-core/fs/f2fs.c
> @@ -1240,6 +1240,11 @@ grub_f2fs_utf16_to_utf8 (grub_uint16_t *in_buf_le)
>    return out_buf;
>  }
>
> +#if __GNUC__ >= 9
> +#pragma GCC diagnostic push
> +#pragma GCC diagnostic ignored "-Waddress-of-packed-member"
> +#endif
> +
>  static grub_err_t
>  grub_f2fs_label (grub_device_t device, char **label)
>  {
> @@ -1260,6 +1265,10 @@ grub_f2fs_label (grub_device_t device, char **label)
>    return grub_errno;
>  }
>
> +#if __GNUC__ >= 9
> +#pragma GCC diagnostic pop
> +#endif
> +
>  static grub_err_t
>  grub_f2fs_uuid (grub_device_t device, char **uuid)
>  {
> --
> 2.20.1