mold
MIT drop-in Unix linker by the lld author — multi-x faster links for Rust, C and C++ debug builds
Rust / Systems · OSS/MIT · 17.7k
Reviewed 2026-10-07 · last push 2026-10-19 · repo checked 2026-10-19
What's Good
MIT (rui314/mold), written by the original author of LLVM lld and in production use since 2021. Free path: install from your distro package manager or build from source, then pass -fuse-ld=mold to clang or GCC 12.1+, or add link-arg=-fuse-ld=mold to rustflags in .cargo/config.toml. The project publishes a reproducible benchmark (suite on Zenodo) where mold beats lld by roughly 4 to 16x on large debug links on a 64-core Threadripper. Supports x86-64, ARM, RISC-V, PowerPC, s390x, LoongArch and more. ★~17.5k.
The Catch
It links ELF binaries for Linux and other Unix-likes; it is not a drop-in for the macOS or Windows system linker. Gains are biggest on many-core machines and large debug outputs; small crates or release builds dominated by codegen will barely notice. Older GCC needs the -B libexec path trick instead of -fuse-ld=mold. Vs wild (newer Rust linker) and lld: mold is the mature, widely adopted fast default.
Verdict
If you build big Rust or C++ on Linux, switching to mold is a one-line config change that cuts link time — free and battle-tested; no help on macOS or Windows.
Embed
Maintainer? Add the badge to your README. It is free, links to this review, and there is no paid version.
Markdown
[](https://stackgems.com/gems/mold)
HTML
<a href="https://stackgems.com/gems/mold"><img src="https://stackgems.com/badge/mold.svg" alt="mold reviewed on Stack Gems" height="20"></a>