Re: [PATCH v9] pgo: add clang's Profile Guided Optimization infrastructure

Peter Zijlstra
2021-06-14T09:43:31Z

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.