One day I'd love to be able to build a Linux distro with a fully working ARMv7 LLVM compiler.. it's looking a few years away still though.
Not so easy, since LLVM developers usually supports just Mach-O (i.e. Darwin family), while ELF (Linux family) developers usually works on GCC...
It shouldn't be too much of a problem then since ELF is just an object format and it's the object code inside (which is arguably exactly the same no matter which container you put it in) that stops anyone from doing this, or more likely the code generation in the first place (lack of support for language features, processors and instruction sets..) rather than anything to do with the choice of operating system.
LLVM just doesn't do very well on ARM, where it works great on x86 and Linux in general..
Well, LLVM running on ARM is more buggy than LLVM running on x86 and this also means that LLVM running on x86 cross-compiling to ARM produce probably less buggy code than LLVM running on ARM compiling to ARM. Unfortunately so far LLVM devs are most interested in x86->arm cross-compilation. Also some of linux specific issues are simply left unfixed due to Apple not putting priority on competitive OS... Ditto for ELF versus Mach-O which I mentioned above.
Well, well, LLVM looks like fantastic project, but, big BUT is that it's BSD licensed and Linux community does not endorse it that much -- at least so far! For Linux community notural choice is GPL hence you do have kind of license clash here... Completely different world exist in Apple domain of course, where LLVM is in the core of their devs plans. What do you thing compiles all the code for iOS including iOS itself? My bet is that it's just LLVM in cross-compilation mode (x86->ARM)...