Re: [PATCH v2 1/4] build: add make macro for making file from file.in

[Jan Beulich <jbeulich@suse.com>]

On 14.11.2025 12:32, Juergen Gross wrote:
> Add a new make macro for creating <file> from <file>.in at build
> time. To be used like this:
> 
> $(foreach file,$(IN_FILES),$(eval $(call apply-build-vars,$(file))))
> 
> This can be used instead of the current approach to perform the similar
> step for file.in during ./configure.
> 
> This will avoid having to run ./configure just because of modifying a
> file depending on a variable set by configure.
> 
> Prepare to have multiple files as source for the replacement patterns.
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
> V2:
> - don't use pattern rule, but create explicit dependency in macro,
>   don't require to rename source files (Jan Beulich, Andrew Cooper)
> ---
>  Config.mk | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/Config.mk b/Config.mk
> index e1556dfbfa..d21d67945a 100644
> --- a/Config.mk
> +++ b/Config.mk
> @@ -159,6 +159,19 @@ define move-if-changed
>  	if ! cmp -s $(1) $(2); then mv -f $(1) $(2); else rm -f $(1); fi
>  endef
>  
> +PATH_FILES := Paths
> +INC_FILES := $(foreach f, $(PATH_FILES), $(XEN_ROOT)/config/$(f).mk)
> +
> +include $(INC_FILES)

Is any of the above part of introducing the macro? "Paths" is already a
specific case of holding patterns that want replacing. In turn ...

> +BUILD_MAKE_VARS := $(foreach f, $(PATH_FILES), $(shell awk '$$2 == ":=" { print $$1; }' $(XEN_ROOT)/config/$(f).mk.in))

... it's not quite clear to me how it can be $(PATH_FILES) here.

> +# Replace @xxx@ markers in $(1).in with $(xxx) variable contents, write to $(1)
> +define apply-build-vars
> + $(1): $(1).in

This being indented by a space looks a little unusual.

Jan

> +	sed $$(foreach v, $$(BUILD_MAKE_VARS), -e 's#@$$(v)@#$$($$(v))#g') <$$< >$$@
> +endef
> +
>  CFLAGS += -fno-strict-aliasing
>  
>  CFLAGS += -std=gnu99