[PATCH RFC 01/12] kbuild: create destination directory for _shipped handling

[Dmitry Baryshkov]

On Mon, 26 Feb 2024 at 08:33, Masahiro Yamada <masahiroy at kernel.org> wrote:
>
> On Mon, Feb 26, 2024 at 11:11 AM Dmitry Baryshkov
> <dmitry.baryshkov at linaro.org> wrote:
> >
> > The driver might decide to put the _shipped files to the subdir.
>
>
>
> Please stop this sentence.
>
> This sounds like we are not learning.
>
> https://lore.kernel.org/all/CAHk-=wgSEi_ZrHdqr=20xv+d6dr5G895CbOAi8ok+7-CQUN=fQ@mail.gmail.com/
>
>
>
>
> > In such
> > case the cmd_copy might fail because the destination directory is not
> > present. Call mkdir -p to make sure that the destination directory is
> > present.
>
>
> There is no justification for this.
>
> If you need a single generated directory
> (drivers/gpu/drm/msm/registers/, divers/gpu/drm/msm/generated/ or whatever)
> that should be super simple.
>
> Why does scripts/Makefile.lib need the modification?

Could you please tell me how I should handle this?
I was looking for a way to generate
drivers/gpu/drm/msm/registers/foo.xml.h and then use it during
compilation.
In drivers/gpu/drm/msm/Makefile I added $(obj)/registers/foo.xml.h as
a dependency to the corresponding object files and then added
drivers/gpu/drm/msm/registers/foo.xml.h_shipped file.
This way Kbuild/make will attempt to call cmd_copy to generate target
file, which thanks to VPATH expansion boils down to `cat
$(srctree)/$(src)/registers/foo.xml.h_shopped >
$(obj)/registers/foo.xml.h`. However this breaks as there is no
$(obj)/registers.


> >
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> > ---
> >  scripts/Makefile.lib | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> > index cd5b181060f1..94373eeac420 100644
> > --- a/scripts/Makefile.lib
> > +++ b/scripts/Makefile.lib
> > @@ -297,7 +297,7 @@ endef
> >  # the copy would be read-only as well, leading to an error when executing the
> >  # rule next time. Use 'cat' instead in order to generate a writable file.
> >  quiet_cmd_copy = COPY    $@
> > -      cmd_copy = cat $< > $@
> > +      cmd_copy = mkdir -p $(shell dirname $@) && cat $< > $@
> >
> >  $(obj)/%: $(src)/%_shipped
> >         $(call cmd,copy)


-- 
With best wishes
Dmitry