LLVM is now able to link entirely to the FreeBSD/amd64 base system. LLVM is a compiler, and LLD is a linker based on the “atom” model. See the full story below, as well as a lengthy discussion from Phoronix.
LLVM-Logo-Derivative-4

LLVM’s LLD linker has been making a lot of progress over the past year and now it’s hit the milestone of being able to link the entire FreeBSD/amd64 base system.

FreeBSD developers have been looking to use LLD as their system linker, following their move a while back now of using LLVM/Clang in place of GCC.

Original article: http://www.phoronix.com/scan.php?page=news_item&px=FreeBSD-LLD-Success

Discussion: https://www.phoronix.com/forums/forum/software/bsd-mac-os-x-hurd-others/922116-the-freebsd-64-bit-base-system-can-now-be-linked-using-lld