lld, part of the LLVM family of projects, is a high-performance linker for the ELF, COFF, and Mach-O object formats. This page describes the ongoing project to use lld as FreeBSD's base system linker.

FreeBSD-CURRENT contains LLD 5.0.0. To build world and kernel with LLD, and install LLD as /usr/bin/ld, add to /etc/src.conf:

WITH_LLD_IS_LD=yes
WITH_LLD_BOOTSTRAP=yes

WITH_LLD_BOOTSTRAP=yes uses lld as the linker for building the FreeBSD world, and has no effect on the linker installed in /usr/bin/ld. WITH_LLD_IS_LD=yes installes lld as /usr/bin/ld, and has no effect on the linker used for building world.

git clone https://github.com/llvm-mirror/llvm
cd llvm/tools
git clone https://github.com/llvm-mirror/lld
mkdir ../build && cd ../build
cmake -G "Unix Makefiles" ../
make -j8

cd build/bin
ln -s lld ld
setenv PATH /path/to/llvm/build/bin:$PATH
setenv LD /path/to/llvm/build/bin
rehash

To check if the changes took effect:

davide@rabbit1:/home/davide/llvm/build/bin $ ld --help | head -n 1
OVERVIEW: LLVM Linker

• Create reserved symbols early so they can be versioned

MIPS

• MIPS Multi-GOT implementation (2017-03-31)

ARM

• Record created ThunkSections in InputSectionDescription (2017-09-12)
• Pre-create ThunkSections at Target specific intervals (2017-06-27)
• Introduce range extension thunks for ARM (2017-06-27)
• Add support for multiple passes to createThunks (2017-06-27)

A FreeBSD ports exp-run is tracked in PR214864.

• go crashes on startup go Github issue 19018
• print/gl2ps needs explicit -L/usr/lib PR218399.

• Rui Ueyama's New LLD linker for ELF talk
• Linking the FreeBSD base system with LLD status update from March 2016
• lld as the FreeBSD base system linker Google Doc