Clang segfault on rpi3 workaround using -O2

[bob prohaska]

On Tue, Feb 19, 2019 at 10:07:57AM -0800, bob prohaska wrote:
> The segfaults in clang during buildworld on rpi3 persisted past
> r339376, but a hint from 
> https://github.com/android-ndk/ndk/issues/386
> suggested trying CFLAGS=-O2 as a long-shot workaround.
> 
> To my surprise, it worked. Three passes were required to
> clear the segfaults, but now a -j4 buildworld/buildkernel
> cycle runs without error to completion. A test of www/chromium
> is underway now, and about half finished with no errors yet,
> using r344113.
> 
> The github report is more than a year old and notes that
> clang was fixed around that time. Is it possible the fix
> didn't find its way into FreeBSD?
> 

The CFLAGS=-O2 workaround also seems to (mostly) work building
www/chromium. There was only one segfault compiling chromium,
restarting make permitted a successful installation. Previously
make segfaulted several times per day, seemingly independent of
swap usage, so it doesn't seem related to VM pressure.

Unfortunately that version of chromium had a (now corrected)
libray bug so it wouldn't run. www/chromium is now up to date
and make is trying again.

There's a bit more detail at
http://www.zefox.net/~fbsd/rpi3/clang_trouble/r344113/readme
in case anybody's interested. 

Thanks for reading,

bob prohaska