Thanks all for the explanations and workaround.
From: "Mojca Miklavec"
To: "smogus"
Cc: "macports-users"
Sent: Friday, October 18, 2019 5:02:55 AM
Subject: Re: mpv, ffmpeg seg fault in macOS catalina
V čet., 17. okt. 2019 22:58 je oseba Gill Bates < [ mailto:smo...@shaw.ca |
smo...@shaw.ca ] > napisala:
I recently updated to catalina (10.15) and Xcode (11.1), installed MacPorts
from source (2.6.1) and had it build mpv and its dependencies. However, mpv
(and ffmpeg for example) do not run apparently related to some new default
compiler option enforcing 16 byte stack alignment? See:
[ https://trac.ffmpeg.org/ticket/8073 | https://trac.ffmpeg.org/ticket/8073 ]
[ https://github.com/mpv-player/mpv/issues/7053 |
https://github.com/mpv-player/mpv/issues/7053 ]
[ https://forums.developer.apple.com/thread/121887 |
https://forums.developer.apple.com/thread/121887 ]
I first saw [ https://github.com/LuaJIT/LuaJIT/issues/518 |
https://github.com/LuaJIT/LuaJIT/issues/518 ] , but that one eventually leads
to the same thread linked above.
BQ_BEGIN
The advice seems to be to revert Xcode but will rebuilding everything with
Xcode 10.3 on macos 10.15 really be a workaround? Or is a better choice to
modify portfiles to include the CFLAG option to disable stack checks as
mentioned in the linked posts and use Xcode 11.1?
BQ_END
Workaround is to either blacklist the compiler which has this option turned on
by default (which is what Chris replied) or in fact use a flag to disable this.
But disabling this flag is not needed for non-broken compilers, so it's
probably better to just blacklist the compiler, and the latest compiler with be
automatically used again when the bug gets fixed.
BQ_BEGIN
"Part B" is a question for my understanding, is this a really an Xcode/compiler
issue or a problem with the source software packages?
BQ_END
I would say that this is in fact an issue with the compiler. As they said, the
bug has been present before, it's just that nobody noticed it until it was
switched on by default. I've seen an email saying that this is likely to be
fixed in one of the next Xcode updates, so it's just a matter of time.
I believe this affects only source code which uses some heavy optimisations,
which is why you would not see it in most of the software where high
performance is not crucially important for the functionality.
Mojca
