Re: [PATCH] Makefile: add $(srctree) to dependency of compile_commands.json target

[Masahiro Yamada]

On Sat, Aug 3, 2024 at 9:52 PM Alexandre Courbot <gnurou@xxxxxxxxx> wrote:
>
> When trying to build the compile_commands.json target from an external
> module's directory, the following error is displayed:
>
>         make[1]: *** No rule to make target 'scripts/clang-tools/gen_compile_commands.py',
>         needed by 'compile_commands.json'. Stop.


Good catch.

But, to reproduce this, O= option is also needed, right?

e.g.

  $ make O=path/to/build/dir M=path/to/external/module/dir




> This appears to be because gen_compile_commands.py is looked up using
> relative path, which doesn't exist from the module's source tree.


The phrase "appears to be ..." is somewhat modest.


You can reword this to pin-point the first bad commit.


For example:

gen_compile_commands.py was previously looked up using a relative path
to $(srctree), but commit b1992c3772e6 ("kbuild: use $(src) instead of
$(srctree)/$(src) for source directory") stopped defining VPATH for
external module builds.



> Prefixing the dependency with $(srctree) fixes the problem.



This needs back-porting.


Please add this:

Fixes: b1992c3772e6 ("kbuild: use $(src) instead of $(srctree)/$(src)
for source directory")


Thanks.




> Signed-off-by: Alexandre Courbot <gnurou@xxxxxxxxx>
> ---
>  Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Makefile b/Makefile
> index 8ad55d6e7b60..52d7dfe4212a 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1980,7 +1980,7 @@ nsdeps: modules
>  quiet_cmd_gen_compile_commands = GEN     $@
>        cmd_gen_compile_commands = $(PYTHON3) $< -a $(AR) -o $@ $(filter-out $<, $(real-prereqs))
>
> -$(extmod_prefix)compile_commands.json: scripts/clang-tools/gen_compile_commands.py \
> +$(extmod_prefix)compile_commands.json: $(srctree)/scripts/clang-tools/gen_compile_commands.py \
>         $(if $(KBUILD_EXTMOD),, vmlinux.a $(KBUILD_VMLINUX_LIBS)) \
>         $(if $(CONFIG_MODULES), $(MODORDER)) FORCE
>         $(call if_changed,gen_compile_commands)
> --
> 2.46.0
>


--
Best Regards

Masahiro Yamada