Re: [XEN PATCH v6 17/31] build: convert binfile use to if_changed

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On Wed, Jul 07, 2021 at 05:48:57PM +0200, Jan Beulich wrote:
> On 01.07.2021 16:09, Anthony PERARD wrote:
> > --- a/xen/common/Makefile
> > +++ b/xen/common/Makefile
> > @@ -80,8 +80,12 @@ config.gz: $(CONF_FILE)
> >  
> >  config_data.o: config.gz
> >  
> > -config_data.S: $(BASEDIR)/tools/binfile
> > -   $(SHELL) $(BASEDIR)/tools/binfile $@ config.gz xen_config_data
> > +quiet_cmd_binfile = BINFILE $@
> > +cmd_binfile = $(SHELL) $< $@ config.gz xen_config_data
> 
> This is an abuse of $< which I consider overly confusing:
> $(BASEDIR)/tools/binfile is not the input file to the rule. Instead
> the script generates an assembly file "out of thin air", with not
> input files at all. The rule and ...
> 
> > +config_data.S: $(BASEDIR)/tools/binfile FORCE
> 
> ... dependency shouldn't give a different impression. What would
> be nice (without having checked how difficult this might be) would
> be if quiet_cmd_binfile and cmd_binfile could move to xen/Rules.mk
> and merely be used from here (and the other location, where the
> same concern obviously applies).

I've though of having cmd_binfile in Rules.mk, but it's made more
complicated by having a "-i" flag used in flask/.

So one things I've writen was:

config_data.S: $(BASEDIR)/tools/binfile FORCE
       $(call if_changed,binfile,,config.gz xen_config_data)
flask-policy.S: $(BASEDIR)/tools/binfile FORCE
       $(call if_changed,binfile,-i,policy.bin xsm_flask_init_policy)

with:
cmd_binfile = $(SHELL) $(BASEDIR)/tools/binfile $(2) $@ $(3)

I thought this would be confusing, so I avoid it.
But maybe with the lists of flags at the end, it would be better:
   $(call if_changed,binfile,policy.bin xsm_flask_init_policy,-i)

Still want to move cmd_binfile to Rules.mk?

But I can at least spell "tools/binfile" instead of using $<.

Thanks,

-- 
Anthony PERARD