FreeBSD and LLVM

[Roman Divacky]

On Tue, May 20, 2008 at 07:06:39PM +0200, Ed Schouten wrote:
> Hello everyone,
> 
> First of all, for those of you who went to BSDCan, I hope you had a
> pleasant flight/trip back home. :-)
> 
> On Saturday I went to the LLVM talk (see http://llvm.org/), which I
> really enjoyed. On Friday Remko Lodder and I already talked with him
> about the LLVM project. I was excited about the project, so I decided to
> give it a try at the office.
> 
> At first I tried LLVM 2.2 with LLVM GCC4 4.2 from Ports, but it didn't
> work like expected. I won't go into many details about it.
> 
> When I discussed the problems I was seeing on my system at the office,
> someone pointed me to the beta tarballs of the upcoming version 2.3,
> which I installed by patching our FreeBSD port.
> 
> 	http://llvm.org/prereleases/2.3/
> 
> As an ideal benchmark, I decided to compile an i386 kernel using the
> LLVM 2.3 snapshot. I didn't expect it to happen, but it works! I was

did you try clang as well? I wonder what it's able to do....

> capable of successfully booting into single user mode and shutting it
> down safely. There is one problem however:
> 
> 	http://llvm.org/bugs/show_bug.cgi?id=2267
> 
> For some reason, the inline asm support of LLVM is incomplete and causes
> compilation errors when generating some of the atomic functions in
> i386/include/atomic.h (lines 262 to 265). To work around this, I made
> the functions non-atomic. Silly, I know, but it was good enough to
> perform some basic tests.
> 
> I think it would be nice if LLVM would once become our standard C
> compiler. LLVM currently uses GCC as its frontend, which proves to be
> somewhat compatible with the original GCC>

yeah... thats a worthy goal :)

thnx!

roman