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

[Neil MacLeod]

Hi Daniel

I can confirm that grub (based on
53e70d30cf0d18e6c28bab0ab8d223a90d3e1b46) is building with gcc-9.1 and
this new patch.

I'm not in a position to run-time test the resulting grub binary, but
it does at least now build!

Many thanks
Neil

On Wed, 29 May 2019 at 12:18, Daniel Kiper <address@hidden> wrote:
>
> 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