[tlbuild] Clang + LLVM 3.5 compilers and build advances

[Mojca Miklavec]

On Fri, Jul 25, 2014 at 6:55 PM, Nelson H. F. Beebe wrote:
> The experience of attempting to build TeX Live releases in recent
> years has shown the need for up-to-date C and C++ compilers.
>
> The Clang + LLVM suite shows great promise, and appears to be nearer
> recent ISO Standards for C and C++ than any other compiler family.
> Unfortunately, in the past, that suite has proved to be quite
> difficult to build successfully, and I now have build logs from over
> 240 attempts over the last five years.
>
> Earlier this month, thanks to my colleague Pieter Bowman, we found a
> solution that solves the build problems for many systems, and I have
> documented that experience here:
>
>         http://www.math.utah.edu/pub/llvm/
>
> That site also provides links to shell scripts and pre-built binary
> trees for sixteen different platforms of mid-July-2014 snapshots of
> the developing 3.5 compiler release.
>
> Because of library dependencies, it is still unclear how useful those
> binary distributions could be, and more work is required to package
> additional libraries.  Nevertheless, I'm encouraged by the progress
> that I've made, and the document describes why builds will not work on
> older systems (e.g., GNU/Linux Red Hat 5).
>
> I'll be happy to hear off-list from any of you who are adventuresome
> enough to try my build recipes for Clang + LLVM snapshots.

Thanks a lot for the links.

I didn't try the recipes, I already have a working version of clang
here. I just wanted to comment about Mac OS X. Clang should work on
x86_64, but because it requires C++11 to build it it is not sufficient
to link against libstdc++ (which is the default on pre-10.9 versions).
You need to build against libc++. And if you are trying to build it on
10.6, you need to install libc++ first.

As far as the abandoned PowerPC architecture is concerned, there's a
very detailed bug & patch report site for clang on
http://www.csl.cornell.edu/~fang/sw/llvm/.

OpenCSW on Solaris contains GCC 4.9.0, so apparently it is possible to
build it (but it might be that one also needs a lot of other
up-to-date tools to be able to do that). There also exist experimental
packages for clang, but it is unclear if they are of sufficient
quality to be usable out-of-the-box (that is: without fixing a bunch
of bugs first).

Mojca