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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Thu, 15 Jul 2021 18:22:45 -0700
Message-ID: <CAHk-=wj8GqP8ughGBbwcyrBNNdtcXVo_G=XjQ1MAUVUuJfUtGg@mail.gmail.com>
Subject: Re: [GIT PULL] fallthrough fixes for Clang for 5.14-rc2
To:     "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc:     "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Kees Cook <keescook@chromium.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>
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On Thu, Jul 15, 2021 at 6:14 PM Gustavo A. R. Silva
<gustavo@embeddedor.com> wrote:
>
> Kees just opened a bug report for this:
>
> https://bugs.llvm.org/show_bug.cgi?id=51094

I don't have an account on that bugzilla, but it might be worth adding
the note that no warning or error should EVER not say where it
happens.

That's the thing that made me pissed off in the first place. I build
my kernels with "make -j128", and if the warning doesn't specify the
filename and the line number, the warning is just unacceptably bad.

How can a compiler _ever_ give a warning without specifying where it is?

The fact that the warning is also entirely wrong-headed in the first
place is just the extra cherry on top.

But at least it should hopefully make it easy to fix in clang - just
remove the incredibly broken thing entirely.

             Linus