Re: [PATCH] x86/build: correctly record dependencies of asm-offsets.s

[Julien Grall <julien@xxxxxxx>]

Hi Jan,

On 01/02/2021 14:56, Jan Beulich wrote:
> Going through an intermediate *.new file requires telling the compiler
> what the real target is, so that the inclusion of the resulting .*.d
> file will actually be useful.
>
> Fixes: 7d2d7a43d014 ("x86/build: limit rebuilding of asm-offsets.h")
> Reported-by: Julien Grall <julien@xxxxxxx>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> ---
> Already on the original patch I did suggest that perhaps Arm would want
> to follow suit. So again - perhaps the rules should be unified by moving
> to common code?
Sorry I missed the original patch. The recent changes looks beneficials 
to Arm as well.
> --- a/xen/arch/x86/Makefile
> +++ b/xen/arch/x86/Makefile
> @@ -241,7 +241,7 @@ efi/buildid.o efi/relocs-dummy.o: $(BASE
>   efi/buildid.o efi/relocs-dummy.o: ;
>   
>   asm-offsets.s: $(TARGET_SUBARCH)/asm-offsets.c $(BASEDIR)/include/asm-x86/asm-macros.h
On Arm, only asm-offsets.c is a pre-requisite. May I ask why you need 
the second on x86?
> -       $(CC) $(filter-out -Wa$(comma)% -flto,$(c_flags)) -S -g0 -o $@.new $<
> +       $(CC) $(filter-out -Wa$(comma)% -flto,$(c_flags)) -S -g0 -o $@.new -MQ $@ 
> $<
>         $(call move-if-changed,$@.new,$@)
>   
>   asm-macros.i: CFLAGS-y += -D__ASSEMBLY__ -P
Cheers,

--
Julien Grall