llvm@21

brew install llvm@21 v21.1.8 Apache-2.0 WITH LLVM-exception keg-only

LLVM 21.x compiler infrastructure toolkit: C/C++ frontend, optimization passes, code generators, and toolchain components.

Why you might care

Use LLVM@21 when you need a specific versioned toolchain for projects requiring cutting-edge optimizations, custom backends, or compatibility with LLVM 21's API. It's keg-only to coexist with other LLVM versions. Primary use: build dependency for clang-based projects, language runtimes, and JIT compilers that target LLVM IR.

Alternatives

GCC Clang LLVM@20 LLVM@19

3.6k

30-day installs · #740

31.0k

90-day · #388

61.9k

365-day · #573

Runtime dependencies

zstd

Build dependencies

cmake ninja python@3.14

Caveats

CLANG_CONFIG_FILE_SYSTEM_DIR: $HOMEBREW_PREFIX/etc/clang
CLANG_CONFIG_FILE_USER_DIR:   ~/.config/clang

LLD is now provided in a separate formula:
  brew install lld@21

Using `clang`, `clang++`, etc., requires a CLT installation at `/Library/Developer/CommandLineTools`.
If you don't want to install the CLT, you can write appropriate configuration files pointing to your
SDK at ~/.config/clang.

To use the bundled libunwind please use the following LDFLAGS:
  LDFLAGS="-L$HOMEBREW_PREFIX/opt/llvm@21/lib/unwind -lunwind"

To use the bundled libc++ please use the following LDFLAGS:
  LDFLAGS="-L$HOMEBREW_PREFIX/opt/llvm@21/lib/c++ -L$HOMEBREW_PREFIX/opt/llvm@21/lib/unwind -lunwind"
Features newer than system libc++ will require the following define to enable:
  CPPFLAGS="-D_LIBCPP_DISABLE_AVAILABILITY"

NOTE: You probably want to use the libunwind and libc++ provided by macOS unless you know what you're doing.

Keg-only reason

:versioned_formula

Blurb generated by claude-haiku-4-5 on today.

Raw metadata

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