[PATCH v3 2/2] kbuild: Use if_changed for font and splash .incbin rules

[Rasmus Villemoes]

On Sun, Apr 05 2026, Simon Glass <sjg at chromium.org> wrote:

> The generated .S files for fonts and splash screens use .incbin with the
> full prerequisite path. When building with O= this bakes an absolute
> path into the .S file. If the build directory is later used on a
> different machine (e.g. in a container), the assembler cannot find the
> source file.
>
> Follow the existing DTB convention: rename the object targets to use
> compound suffixes (.ttf.o, .bmp.o), switch the pattern rules from
> direct $(call cmd,...) to FORCE + $(call if_changed,...), and register
> the new suffixes with intermediate_targets so that kbuild loads their
> .cmd files. This lets if_changed detect when the recorded command
> (including source paths) has changed and regenerate the .S file
> automatically.
>
> The EFI rule is left unchanged since its prerequisite is a generated
> file in the build directory, like the DTB and DTBO rules.
>
> Suggested-by: Rasmus Villemoes <ravi at prevas.dk>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
> Changes in v3:
> - Use if_changed with compound suffixes (.ttf.o, .bmp.o)
>
> Changes in v2:
> - Move U-Boot .incbin rules to Makefile.lib-u-boot first (previous patch)
> - Drop the EFI .incbin change since .efi files are generated, not source
> - Use per-file AFLAGS instead of modifying a_flags in Makefile.lib
>

> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index e625f99986e..067c38c4cdd 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -438,7 +438,9 @@ intermediate_targets = $(foreach sfx, $(2), \
>  targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
>  	   $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
>  	   $(call intermediate_targets, .lex.o, .lex.c) \
> -	   $(call intermediate_targets, .tab.o, .tab.c .tab.h)
> +	   $(call intermediate_targets, .tab.o, .tab.c .tab.h) \
> +	   $(call intermediate_targets, .ttf.o, .ttf.S) \
> +	   $(call intermediate_targets, .bmp.o, .bmp.S)

Do these extra lines need to go here, causing a conflict with the next
kbuild sync, or could one instead add

  targets += $(call intermediate_targets, .ttf.o, .ttf.S) \
             $(call intermediate_targets, .bmp.o, .bmp.S)

in the new Makefile.lib-u-boot? I think that would make more sense. But
there may be some ordering of makefile includes that makes that not
posssible.

At the very least, I think the additions to targets should go in a new
'targets +=', just to separate them a little better from upstream and
making it pure code addition instead of having to modify that last line
to add a continuation marker.

Rasmus