Installation of GNAT LLVM on macOS

General
1

Hello,

I am trying to build GNAT LLVM on macOS (Apple Silicon) and I am running into toolchain issues.

Current setup:

  • LLVM 21.1.8 (Homebrew)

  • Clang 21.1.8

  • GNAT Native 14.2.1

  • gprbuild 26.0.1

  • Alire configured with gnat_native=14.2.1

I configured LLVM using:

  • PATH=/opt/homebrew/opt/llvm@21/bin

  • CPPFLAGS=/opt/homebrew/opt/llvm@21/include

  • LDFLAGS=/opt/homebrew/opt/llvm@21/lib

llvm-config --version correctly shows 21.1.8.

Initially I had:

  • opt: command not found

  • gprbuild: c++ compiler not found

After fixing those, make now fails with:

clang: error: unknown argument: '-gnatea'
clang: error: unknown argument: '-gnatez'
gnatmake: "xoscons.adb" compilation error

It looks like Clang is being invoked instead of the GNAT Ada compiler.

Also, my GNAT installation seems incomplete:

  • gnatmake, gnatbind, gnatlink exist

  • but gnat, gnatls, and gnatgcc are missing

I also installed Homebrew GCC 15, but the build still fails with the same errors.

Has anyone successfully built GNAT LLVM on macOS Apple Silicon recently?
Could you share:

  • the exact LLVM / Clang / GNAT versions you used,

  • whether extra setup is needed on macOS,

  • and whether the missing GNAT binaries indicate a broken Alire toolchain installation?

Thanks