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From:   Bill Wendling <morbo@google.com>
Date:   Sat, 12 Jun 2021 15:47:56 -0700
Message-ID: <CAGG=3QUFRM85bpyjdokO93=Nem_w7-784-_qihP1P_CJMOsdqg@mail.gmail.com>
Subject: Re: [PATCH v9] pgo: add clang's Profile Guided Optimization infrastructure
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Kees Cook <keescook@google.com>, Jonathan Corbet <corbet@lwn.net>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Linux Doc Mailing List <linux-doc@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Nathan Chancellor <natechancellor@gmail.com>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Sami Tolvanen <samitolvanen@google.com>,
        Fangrui Song <maskray@google.com>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@kernel.org>
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On Sat, Jun 12, 2021 at 1:56 PM Bill Wendling <morbo@google.com> wrote:
> On Sat, Jun 12, 2021 at 1:25 PM Peter Zijlstra <peterz@infradead.org> wrote:
> > On Sat, Jun 12, 2021 at 12:10:03PM -0700, Bill Wendling wrote:
> > Yes it is, but is that sufficient in this case? It very much isn't for
> > KASAN, UBSAN, and a whole host of other instrumentation crud. They all
> > needed their own 'bugger-off' attributes.
> >
> Now, for the "nointr" issue. I'll see if we need an additional change for that.
>
The GCOV implementation disables profiling in those directories where
instrumentation would fail. We do the same. Both clang and gcc seem to
treat the no_instrument_function attribute similarly.

-bw