[FFmpeg-devel] [PATCH v2] configure: Work around a start-up crash when building with clang.

[Michael Niedermayer]

On Thu, Nov 21, 2019 at 09:44:56AM -0500, Rick Kern wrote:
> On Wed, Nov 20, 2019 at 11:29 AM Hendrik Leppkes <h.leppkes at gmail.com>
> wrote:
> 
> > On Wed, Nov 20, 2019 at 5:00 PM Timo Rothenpieler <timo at rothenpieler.org>
> > wrote:
> > >
> > > On 20.11.2019 13:51, Rick Kern wrote:
> > > > The current version of clang enables stack checking by default, causing
> > > > a crash when binaries are run.
> > >
> > > Why does it trigger a crash? Doesn't it indicate something is wrong that
> > > should be fixed instead?
> >
> 
> Here's the discussion about the compiler bug -
> https://forums.developer.apple.com/thread/121887
> 
> Maybe this is too heavy-handed. Disabling avx, avx2, and avx512 fixes the
> issue too, so maybe this is the better than disabling a security feature.
> Detecting the compiler bug in configure and disabling only when present
> would have less impact on performance.
> 
> I'm torn between automatically disabling it when the bug is detected, or
> bailing from configure with an error message to disable it.  What's the
> best option?

can it be worked around automatically ?
IIUC one workaround reduces speed, the other reduces security.
its maybe better to "ask" the user what she cares more about if theres no
"universal" workaround and either means loosing something or at least
give a clear warning at the end of configure that describes the issue
and what the user can do to get the other workaround.

Thanks

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

It is what and why we do it that matters, not just one of them.
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