Re: [XEN PATCH v8 01/47] build: factorise generation of the linker scripts

[Julien Grall <julien@xxxxxxx>]

Hi,

On 14/12/2021 17:09, Anthony PERARD wrote:
> On Tue, Dec 14, 2021 at 04:54:21PM +0000, Julien Grall wrote:
> > On 25/11/2021 13:39, Anthony PERARD wrote:
> > > diff --git a/xen/Rules.mk b/xen/Rules.mk
> > > +# Linker scripts, .lds.S -> .lds
> > > +quiet_cmd_cpp_lds_S = LDS     $@
> > > +cmd_cpp_lds_S = $(CPP) -P $(call cpp_flags,$(a_flags)) -D__LINKER__ -MQ $@ -o $@ 
> > > $<
> > > +
> > > diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
> > > +xen.lds: xen.lds.S FORCE
> > > +       $(call if_changed,cpp_lds_S)
> > Sorry, I haven't really followed the build system rework. Could you explain
> > why it is necessary to add FORCE?
> This new rules make use of a new macro "if_changed", and we need to
> execute this new macro every time, even if the source file hasn't been
> modified.
>
> if_changed, in addition to checking if the source is newer than the
> target that make does, also compare the command line used to generate
> the target. If the command line have changed, the macro update the
> target.
Ah, that's the part I was missing. Thanks for the clarification! With that:

Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

Cheers,

--
Julien Grall