Re: [gentoo-dev] Clang toolchain [Was: status of bugs blocking gcc-4.8.3]

[Matthias Maier]

Am 27. Oct 2014, 11:14 schrieb Alexis Ballier <aballier@g.o>:

> By the way, any help for maintaining the libc++ stack is very welcome;
> as you can see from the age of the current snapshots, it's been some
> time I've not been playing with it.
>
>
> Some notes:
> - why not adding a clang subprofile ? there's one for amd64-fbsd; I had
>   been able to build a complete stage 3 without too much trouble.
>   There's probably nothing bsd specific there, so moving
>   generic code from there to profiles/features should work.

Yes, it looks fairly generic. This is definitely worth a try.

> - it'd be worth fixing/improving libunwind support, esp. as you write
>   here on the clang 'spec' parts; I don't remember if there were other
>   issues, but it was a bit pointless if we can't get rid of libgcc_s
>   because of clang (maybe there were even symbol collisions?)
> - libcxxabi is probably the new way to go instead of libcxxrt; last
>   time I checked there was a chicken and egg problem: libcxxabi needed
>   clang + libc++ to build, so bootstrapping the stack was a bit
>   painful.

The Toolchain behavior on GNU/Linux is fairly tailored to using gcc at
the moment (just grep for gcc_ on
tools/clang/lib/Driver/{Tools|Toolchain}.cpp).

In order to really pull off a clang/libc++ toolchain independent of gcc
assistance would involve quite a bunch of (preferably upstream) work...

> - there are a few todos in libcxx ebuild (mainly libsupc++ support, but
>   the same could apply to libcxxabi)
> - it'd be interesting to have stand-alone ebuilds for gcc's crt files;
>   or better, find BSD-like alternatives
>
> Alexis.

Best,
Matthias