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Date:   Mon, 14 Jun 2021 11:43:12 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Bill Wendling <morbo@google.com>
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Subject: Re: [PATCH v9] pgo: add clang's Profile Guided Optimization
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On Sun, Jun 13, 2021 at 11:07:26AM -0700, Bill Wendling wrote:

> > > 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.

Both seem to emit instrumentation, so they're both, simliarly, *broken*.

noinstr *MUST* disable all compiler generated instrumentation. Also see:

  https://lkml.kernel.org/r/20210527194448.3470080-1-elver@google.com

I'll go mark GCOV support as BROKEN for x86.