Re: [PATCH bpf-next] libbpf: Add cscope and TAGS targets to Makefile

[Andrii Nakryiko <andrii.nakryiko@gmail.com>]

On Thu, Oct 3, 2019 at 1:46 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
>
> Using cscope and/or TAGS files for navigating the source code is useful.
> Add simple targets to the Makefile to generate the index files for both
> tools.
>
> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
> ---

Thanks a lot for adding this!

I tested cscope only and it works (especially without -k), so:

Tested-by: Andrii Nakryiko <andriin@fb.com>


>  tools/lib/bpf/.gitignore |  2 ++
>  tools/lib/bpf/Makefile   | 10 +++++++++-
>  2 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/.gitignore b/tools/lib/bpf/.gitignore
> index d9e9dec04605..c1057c01223e 100644
> --- a/tools/lib/bpf/.gitignore
> +++ b/tools/lib/bpf/.gitignore
> @@ -3,3 +3,5 @@ libbpf.pc
>  FEATURE-DUMP.libbpf
>  test_libbpf
>  libbpf.so.*
> +TAGS
> +cscope.*
> diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
> index c6f94cffe06e..57df6b933196 100644
> --- a/tools/lib/bpf/Makefile
> +++ b/tools/lib/bpf/Makefile
> @@ -262,7 +262,7 @@ clean:
>
>
>
> -PHONY += force elfdep bpfdep
> +PHONY += force elfdep bpfdep cscope TAGS
>  force:
>
>  elfdep:
> @@ -271,6 +271,14 @@ elfdep:
>  bpfdep:
>         @if [ "$(feature-bpf)" != "1" ]; then echo "BPF API too old"; exit 1 ; fi
>
> +cscope:
> +       (echo \-k; echo \-q; for f in *.c *.h; do echo $$f; done) > cscope.files
> +       cscope -b -f cscope.out

1. I'd drop -k, given libbpf is user-land library, so it's convenient
to jump into system headers for some of BPF definitions.
2. Wouldn't this be simpler and work exactly the same?

ls *.c *.h > cscope.files
cscope -b -q -f cscope.out


> +
> +TAGS:

let's make it lower-case, please? Linux makefile supports both `make
tags` and `make TAGS`, but all-caps is terrible :)

> +       rm -f TAGS
> +       echo *.c *.h | xargs etags -a

nit: might as well do ls *.c *.h for consistency with cscope
suggestion above (though in both cases we just rely on shell expansion
logic, so doesn't matter).

> +
>  # Declare the contents of the .PHONY variable as phony.  We keep that
>  # information in a variable so we can use it in if_changed and friends.
>  .PHONY: $(PHONY)
> --
> 2.23.0
>