-Wimplicit-fallthrough not working with ccache

[Kalle Valo <kvalo@codeaurora.org>]

(replying to an old thread but renaming it)

Kalle Valo <kvalo@codeaurora.org> writes:

> "Gustavo A. R. Silva" <gustavo@embeddedor.com> wrote:
>
>> In preparation to enabling -Wimplicit-fallthrough, mark switch cases
>> where we are expecting to fall through.
>> 
>> Notice that in this particular case, I replaced "pass through" with
>> a proper "fall through" comment, which is what GCC is expecting
>> to find.
>> 
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
>
> Patch applied to ath-next branch of ath.git, thanks.
>
> f1d270ae10ff ath10k: htt_tx: mark expected switch fall-throughs

Gustavo, I enabled W=1 on my ath10k build checks and it took me a while
to figure out why GCC was warning about fall through annotations missing
even I knew you had fixed them. Finally I figured out that the reason
was ccache, which I need because I work with different branches and need
to recompile the kernel quite often.

If the plan is to enable -Wimplicit-fallthrough by default in the kernel
IMHO this might become an issue, as otherwise people using ccache start
seeing lots of invalid warnings. Apparently CCACHE_COMMENTS=1 will fix
that but my version of ccache doesn't support it, and how would everyone
learn that trick anyway? Or maybe CCACHE_COMMENTS can enabled through
kernel Makefile?

-- 
Kalle Valo