Re: [lmi] LLVM libc++

[Vadim Zeitlin]

On Wed, 5 Oct 2022 15:58:03 +0000 Greg Chicares <gchicares@sbcglobal.net> wrote:

GC> On 10/4/22 16:12, Vadim Zeitlin wrote:
GC> > On Tue, 4 Oct 2022 15:02:26 +0000 Greg Chicares <gchicares@sbcglobal.net> 
wrote:
GC> > 
GC> > GC> I'm doing something equivalent to your patch, but I've run into two
GC> > GC> linker problems.
GC> 
GC> Without even addressing those problems yet, I've found another, which
GC> is triggered by llvm's unwind library, with gcc and libstdc++'s regex
GC> in combination with ubsan:

 Sorry, but how is this related to llvm libunwind? I must be missing
something, but I just don't see how does it affect this?

GC> We've seen something like this before:
GC> 
GC>   commit 5a4fcaed7309f5d4caee3443538ceb3edf0e119b
GC>   Author: Gregory W. Chicares <gchicares@sbcglobal.net>
GC>   Date:   2022-08-18T16:22:15+00:00
GC>   [...]
GC>   +# gcc-12 gives spurious warnings when <regex> is used. See:
GC>   +#   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105562
GC>   +# For lmi, this seems to affect only UBSAN builds.
GC> 
GC> Now, with llvm's unwinder, it affects unit tests as well,
GC> and the resolution is the same: '-Wno-maybe-uninitialized',
GC> only if target-is-affected AND gcc AND ubsan.

 Could we perhaps disable it just for <regex> contents, i.e. use the usual
pragma push/ignored/pop around it?

VZ

pgpFDfP4JSqeL.pgp
Description: PGP signature