[U-Boot] [U-Boot, v0, 07/20] vsprintf.c: add wide string (%ls) support

[Tom Rini <trini@konsulko.com>]

On Tue, Aug 08, 2017 at 08:14:41PM -0400, Rob Clark wrote:
> On Tue, Aug 8, 2017 at 7:55 PM, Alexander Graf <agraf@suse.de> wrote:
> >
> >
> > On 09.08.17 00:39, Rob Clark wrote:
> >>
> >> On Tue, Aug 8, 2017 at 7:08 PM, Heinrich Schuchardt <xypron.glpk@gmx.de>
> >> wrote:
> >>>
> >>> On 08/09/2017 12:44 AM, Rob Clark wrote:
> >>>>
> >>>> On Tue, Aug 8, 2017 at 6:03 PM, Heinrich Schuchardt <xypron.glpk@gmx.de>
> >>>> wrote:
> >>>>>
> >>>>> On 08/04/2017 09:31 PM, Rob Clark wrote:
> >>>>>>
> >>>>>> This is convenient for efi_loader which deals a lot with utf16.
> >>>>>>
> >>>>>> Signed-off-by: Rob Clark <robdclark@gmail.com>
> >>>>>
> >>>>>
> >>>>> Please, put this patch together with
> >>>>> [PATCH] vsprintf.c: add GUID printing
> >>>>> https://patchwork.ozlabs.org/patch/798362/
> >>>>> and
> >>>>> [PATCH v0 06/20] common: add some utf16 handling helpers
> >>>>> https://patchwork.ozlabs.org/patch/797968/
> >>>>> into a separate patch series.
> >>>>>
> >>>>> These three patches can be reviewed independently of the efi_loader
> >>>>> patches and probably will not be integrated via the efi-next tree.
> >>>>
> >>>>
> >>>> I'll resend these as a separate patchset, and just not in next
> >>>> revision of efi_loader patchset that it is a dependency
> >>>>
> >>>>>> ---
> >>>>>>   lib/vsprintf.c | 30 ++++++++++++++++++++++++++++--
> >>>>>>   1 file changed, 28 insertions(+), 2 deletions(-)
> >>>>>>
> >>>>>> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> >>>>>> index 874a2951f7..0c40f852ce 100644
> >>>>>> --- a/lib/vsprintf.c
> >>>>>> +++ b/lib/vsprintf.c
> >>>>>> @@ -17,6 +17,7 @@
> >>>>>>   #include <linux/ctype.h>
> >>>>>>
> >>>>>>   #include <common.h>
> >>>>>> +#include <charset.h>
> >>>>>>
> >>>>>>   #include <div64.h>
> >>>>>>   #define noinline __attribute__((noinline))
> >>>>>> @@ -270,6 +271,26 @@ static char *string(char *buf, char *end, char
> >>>>>> *s, int field_width,
> >>>>>>        return buf;
> >>>>>>   }
> >>>>>>
> >>>>>> +static char *string16(char *buf, char *end, u16 *s, int field_width,
> >>>>>> +             int precision, int flags)
> >>>>>> +{
> >>>>>> +     u16 *str = s ? s : L"<NULL>";
> >>>>>
> >>>>> Please, do not use the L-notation here as it requires -fshort-wchar.
> >>>>> As we currently cannot switch the complete project to C11 you cannot
> >>>>> use
> >>>>> the u-notation either.
> >>>>
> >>>>
> >>>> current plan was to either switch whole project to -fshort-wchar or
> >>>> c11 and rework these patches (as well as a few patches in the
> >>>> efi_loader patchset).  (In the c11 case, I'm not sure what we'll use
> >>>> as the fmt string, since afaict that isn't specified.  We could use %S
> >>>> although that seems to be a deprecated way to do %ls, or something
> >>>> different like %A, I guess)..
> >>>>
> >>>> how far are we from c11?  If there is stuff I can do to help let me
> >>>> know.  If feasible, I'd rather do that first rather than have a bunch
> >>>> of stuff in vsprintf and elsewhere that needs to be cleaned up later
> >>>> after the switch.
> >>>
> >>>
> >>> buildman downloads very old compilers (gcc < 4.8) from kernel.org which
> >>> do not support C11.
> >>> Travis CI uses Ubuntu 14.04 with gcc 4.8.4 which incorrectly throws an
> >>> error for disk/part.c in C11 mode.
> >>
> >>
> >> ugg, 4.8 is pretty old..   Not sure how much older than 4.8 buildman
> >> uses.  It seems like *some* c11 was supported w/ >=4.6 so if we
> >> approach the conversion piecemeal (for example skipping code that
> >> triggers gcc bugs on old compilers) we might be able to keep 4.8.4
> >> working until travis provides something newer.
> >>
> >> (btw, even going back say 8 fedora releases or more, I've used distro
> >> packaged arm and aarch64 toolchains exclusively.. are there that many
> >> distro's where we really can't assume availability of an
> >> cross-toolchain?  If there isn't something newer from kernel.org can
> >> we just drop relying on ancient prebuilt toolchains?  I'm anyways not
> >> hugely a fan of downloading binary executables from even kernel.org,
> >> instead of using something from a distro build system which I at least
> >> know is very locked down.)
> >>
> >>> To get things right we would have to
> >>> * build our own cross tool chains based on a current gcc version
> >>> * use our own tool chain in Travis for x86-64 or use a docker
> >>>    container with a current gcc version.
> >>>
> >>> In the long run heading for C11 would be the right thing to do.
> >>> Until then use an initializer { '<', 'N', 'U', 'L', 'L', '>' }.
> >>> It looks ugly but does not consume more bytes once compiled.
> >>>
> >>
> >> Sure, that I'm less worried about, as much as adding stuff that is
> >> very soon going to be legacy.  Even in vfprintf.c it isn't such a big
> >> deal, as efi_loader where it would be more cumbersome.
> >>
> >> Maybe we can write out u"<NULL>" longhand in vsprintf.c as you
> >> suggest, but restrict efi_loader to gcc >= 4.9?  That seems like it
> >> shouldn't be a problem for any arm/arm64 device and it shouldn't be a
> >> problem for any device that is likely to have an efi payload to load
> >> in the first place..
> >
> >
> > I don't understand? We enable EFI_LOADER on all arm/arm64 systems for a good
> > reason, so they all get checked by travis. If we break travis, that won't do
> > anyone any good.
> 
> I was more thinking if there was some oddball non-arm arch that u-boot
> supported which didn't haven good mainline gcc support and required
> something ancient ;-)

So, with v2018.01 I want to say that for ARM*, gcc-6.x is the minimum.

Looking around, nds32 requires gcc-4.4.4.  NDS32 folks, is there a newer
toolchain available?

Other than that, everything else has a gcc-6.x available in some form or
another.  Thanks!

-- 
Tom
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