On Sat, Aug 3, 2024 at 10:47 PM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
>
> 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
I am building the module as follows:
$ make -C ../linux/build M=$PWD modules compile_commands.json
The kernel itself was built with O=build though.
> > 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.
Thanks, that's much better. I should indeed have bisected to find the
source of the regression.
>
>
>
> > 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")
Done, and sent v2 as well.
Thank you!
Alex.
