[PATCH v2] drm/xe: replace 'grouped target' in Makefile with pattern rule

[Lucas De Marchi]

On Sun, Feb 25, 2024 at 01:07:08PM +0200, Dafna Hirschfeld wrote:
>On 21.02.2024 23:49, Lucas De Marchi wrote:
>>On Wed, Feb 21, 2024 at 11:55:56AM +0200, Dafna Hirschfeld wrote:
>>>Since 'grouped target' is used only in 'make' 4.3, it should
>>>be avoided. Replace it with 'multi-target pattern rule' which
>>>has the same behavior.
>>>
>>>Signed-off-by: Dafna Hirschfeld <dhirschfeld at habana.ai>
>>>---
>>>v2 changes: instead of removing 'grouped target' we replace it with pattern-rule
>>>here is v1: https://lore.kernel.org/intel-xe/20240219135845.1463992-1-dhirschfeld@habana.ai/
>>>
>>>drivers/gpu/drm/xe/Makefile | 2 +-
>>>1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>>diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
>>>index c531210695db..64903841fbd4 100644
>>>--- a/drivers/gpu/drm/xe/Makefile
>>>+++ b/drivers/gpu/drm/xe/Makefile
>>>@@ -42,7 +42,7 @@ generated_oob := $(obj)/generated/xe_wa_oob.c $(obj)/generated/xe_wa_oob.h
>>>quiet_cmd_wa_oob = GEN     $(notdir $(generated_oob))
>>>     cmd_wa_oob = mkdir -p $(@D); $^ $(generated_oob)
>>>
>>>-$(generated_oob) &: $(obj)/xe_gen_wa_oob $(srctree)/$(src)/xe_wa_oob.rules
>>>+$(obj)/generated/%.c $(obj)/generated/%.h:  $(obj)/xe_gen_wa_oob $(srctree)/$(src)/xe_wa_oob.rules
>>
>>that means we can only ever have generated files for xe_wa_oob and
>>nothing else (or we would have to change this line too.
>>
>>did you see any issue with the line I suggested?
>
>I checked your suggestion:
>"
>%/generated/xe_wa_oob.c %/generated/xe_wa_oob.h: $(obj)/xe_gen_wa_oob $(srctree)/$(src)/xe_wa_oob.rules
>"
>which works as well. But the doc says "Always use $(obj) when referring to generated files."
>
>https://www.kernel.org/doc/html/latest/kbuild/makefiles.html#custom-rules
>
>So I think we rather keep it.

humn... but % at the beginning is already globbing it.
Note that the syntax I suggested is the very same used in /Makefile:

	# This exploits the 'multi-target pattern rule' trick.
	# The syncconfig should be executed only once to make all the targets.
	# (Note: use the grouped target '&:' when we bump to GNU Make 4.3)
	#
	# Do not use $(call cmd,...) here. That would suppress prompts from syncconfig,
	# so you cannot notice that Kconfig is waiting for the user input.
	%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h %/generated/rustc_cfg: $(KCONFIG_CONFIG)
		$(Q)$(kecho) "  SYNC    $@"
		$(Q)$(MAKE) -f $(srctree)/Makefile syncconfig

Alternative would be to use

	$(obj)/generated/%_wa_oob.c $(obj)/generated/%_wa_oob.h:

... that should also work (although ugly), but since the root Makefile
skips it, I'd just use the very same pattern.

The syntax you used is wrong because then the rule matches any 
generated/*.{c,h}, even if the file has nothing to do with oob WAs.

Lucas De Marchi

>
>thanks,
>Dafna
>
>
>>
>>Lucas De Marchi
>>
>>>	$(call cmd,wa_oob)
>>>
>>>uses_generated_oob := \
>>>-- 
>>>2.34.1
>>>