Re: [XEN PATCH v8 30/47] build: rework "headers*.chk" prerequisite in include/

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On Tue, Dec 21, 2021 at 03:07:52PM +0100, Jan Beulich wrote:
> On 25.11.2021 14:39, Anthony PERARD wrote:
> > @@ -81,10 +81,21 @@ ifeq ($(XEN_TARGET_ARCH),$(XEN_COMPILE_ARCH))
> >  
> >  all: $(obj)/headers.chk $(obj)/headers99.chk $(obj)/headers++.chk
> >  
> > -PUBLIC_HEADERS := $(filter-out $(src)/public/arch-% 
> > $(src)/public/dom0_ops.h, $(wildcard $(src)/public/*.h $(src)/public/*/*.h) 
> > $(public-y))
> > +public-hdrs-path := $(srcdir)/public
> >  
> > -PUBLIC_C99_HEADERS := $(src)/public/io/9pfs.h $(src)/public/io/pvcalls.h
> > -PUBLIC_ANSI_HEADERS := $(filter-out $(src)/public/%ctl.h 
> > $(src)/public/xsm/% $(src)/public/%hvm/save.h $(PUBLIC_C99_HEADERS), 
> > $(PUBLIC_HEADERS))
> > +public-list-headers = $(wildcard $1/*.h $1/*/*.h)
> > +public-filter-headers = $(filter-out $(addprefix 
> > $(public-hdrs-path)/,$($1-filter)), $($1))
> > +
> > +public-c99-headers := io/9pfs.h io/pvcalls.h
> > +public-headers := $(call public-list-headers,$(public-hdrs-path)) 
> > $(public-y)
> > +public-ansi-headers := $(public-headers)
> 
> Personally I find it odd for public-c99-headers to be first in this group.
> Further down, in the upper-case counterparts, you have it at the end (still
> in context below).
> 
> > +public-headers-filter := dom0_ops.h arch-%
> 
> What is the criteria to be listed here vs ...
> 
> > +public-ansi-headers-filter := %ctl.h xsm/% %hvm/save.h 
> > $(public-headers-filter) $(public-c99-headers)
> 
> ... outside of that macro's expansion here? There's no other use of the
> macro that I can spot, so its presence is puzzling me.

The "%-filter" macro are used by the macro "public-filter-headers",
which takes "$(%)" and filter-out "$(%-filter)".

Currently, PUBLIC_ANSI_HEADERS is PUBLIC_HEADERS with headers
filtered-out.
And PUBLIC_HEADERS is public-y with headers filtered-out.

In my patch, I derive PUBLIC_ANSI_HEADERS from public-y, so I also need
to use the filter used to generate PUBLIC_HEADERS. So
$(public-headers-filter) is both used on its own and in the ansi-filter.

> > +PUBLIC_HEADERS := $(call public-filter-headers,public-headers)
> > +PUBLIC_ANSI_HEADERS := $(call public-filter-headers,public-ansi-headers)
> > +PUBLIC_C99_HEADERS := $(addprefix $(public-hdrs-path)/, 
> > $(public-c99-headers))
> 
> While benign right now, wouldn't it be more consistent if
> public-filter-headers was also applied in this last case? Or is
> there a reason not to?

It wouldn't work at the moment because $(public-c99-headers) aren't
prefix with "$(public-hdrs-path)" like $(public-headers). This is
because I'm using $(public-c99-headers) in
$(public-ansi-headers-filter).

Maybe I should just had the prefix to the c99-headers and removing the
prefix when using it in the filter, something like that:

    public-c99-headers := $(addprefix $(public-hdrs-path)/,io/9pfs.h 
io/pvcalls.h)
    public-ansi-headers-filter := %ctl.h xsm/% %hvm/save.h 
$(public-headers-filter) \
        $(patsubst $(public-hdrs-path)/%,%,$(public-c99-headers))

then I thin that would work:
    PUBLIC_C99_HEADERS := $(call public-filter-headers,public-c99-headers)

I could put an empty "public-c99-headers-filter :=" somewhere, just in
case one is looking for it later.

Thanks,

-- 
Anthony PERARD