# mold

> MIT drop-in Unix linker by the lld author — multi-x faster links for Rust, C and C++ debug builds

**Category:** Rust  
**Pricing:** open-source  
**URL:** https://github.com/rui314/mold  
**GitHub:** https://github.com/rui314/mold  
**Added:** 2026-10-07

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## The Hook

mold is a drop-in replacement for ld, gold and lld that makes the link step of compiled builds much faster, which matters most in edit-rebuild loops on big Rust, C and C++ projects where linking dominates the wait.

## 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.