On Thu, 31 Mar 2022 at 17:03, Marc Glisse via Libstdc++
<libstd...@gcc.gnu.org> wrote:
>
> On Thu, 31 Mar 2022, Matthias Kretz via Gcc-patches wrote:
>
> > I like it. But I'd like it even more if we could have
> >
> > #elif defined _UBSAN
> > __ubsan_invoke_ub("reached std::unreachable()");
> >
> > But to my knowledge UBSAN has no hooks for the library like this (yet).
>
> -fsanitize=undefined already replaces __builtin_unreachable with its own
> thing, so I was indeed going to ask if the assertion / trap provide a
> better debugging experience compared to plain __builtin_unreachable, with
> the possibility to get a stack trace (UBSAN_OPTIONS=print_stacktrace=1),
> etc? Detecting if (the right subset of) ubsan is enabled sounds like a
> good idea.
Does UBsan define a macro that we can use to detect it?
