diff --git a/nix-darwin/home.nix b/nix-darwin/home.nix
index e884a77..a7239b9 100644
--- a/nix-darwin/home.nix
+++ b/nix-darwin/home.nix
@@ -27,6 +27,7 @@
       #     patches = [ ./change-hello-to-hi.patch ];
       #   });
       # })
+      (import ./overlays/ghdl-llvm.nix)
     ];
     # Configure your nixpkgs instance
     config = {
@@ -87,7 +88,11 @@
     sshfs
     libqalculate
     imagemagick
+
+    # compiler stuff
     llvm
+    libllvm
+    ghdl-llvm
 
     # Simulators
     # ngspice
diff --git a/nix-darwin/overlays/ghdl-llvm.nix b/nix-darwin/overlays/ghdl-llvm.nix
new file mode 100644
index 0000000..4ccea2d
--- /dev/null
+++ b/nix-darwin/overlays/ghdl-llvm.nix
@@ -0,0 +1,126 @@
+{ stdenv
+, fetchFromGitHub
+, callPackage
+, gnat
+, zlib
+, llvm
+, lib
+, gcc-unwrapped
+, texinfo
+, gmp
+, mpfr
+, libmpc
+, gnutar
+, glibc
+, makeWrapper
+, backend ? "mcode"
+, isDarwin ? stdenv.isDarwin
+}:
+
+assert backend == "mcode" || backend == "llvm" || backend == "gcc";
+
+stdenv.mkDerivation (finalAttrs: {
+  pname = "ghdl-${backend}";
+  version = "4.1.0";
+
+  src = fetchFromGitHub {
+    owner  = "ghdl";
+    repo   = "ghdl";
+    rev    = "v${finalAttrs.version}";
+    hash   = "sha256-tPSHer3qdtEZoPh9BsEyuTOrXgyENFUyJqnUS3UYAvM=";
+  };
+
+  LIBRARY_PATH = "${stdenv.cc.libc}/lib";
+
+  nativeBuildInputs = [
+    gnat
+  ] ++ lib.optionals (backend == "gcc") [
+    texinfo
+    makeWrapper
+  ];
+  buildInputs = [
+    zlib
+  ] ++ lib.optionals (backend == "llvm") [
+    llvm
+  ] ++ lib.optionals (backend == "gcc") [
+    gmp
+    mpfr
+    libmpc
+  ];
+  propagatedBuildInputs = [
+  ] ++ lib.optionals (backend == "llvm" || backend == "gcc") [
+    zlib
+  ];
+
+  preConfigure = ''
+    # If llvm 7.0 works, 7.x releases should work too.
+    sed -i 's/check_version  7.0/check_version  7/g' configure
+  '' + lib.optionalString (backend == "gcc") ''
+    ${gnutar}/bin/tar -xf ${gcc-unwrapped.src}
+  '';
+
+  configureFlags = [
+    # See https://github.com/ghdl/ghdl/pull/2058
+    "--disable-werror"
+    "--enable-synth"
+  ] ++ lib.optionals (backend == "llvm") [
+    "--with-llvm-config=${llvm.dev}/bin/llvm-config"
+  ] ++ lib.optionals (backend == "gcc") [
+    "--with-gcc=gcc-${gcc-unwrapped.version}"
+  ];
+
+  buildPhase = lib.optionalString (backend == "gcc") ''
+    make copy-sources
+    mkdir gcc-objs
+    cd gcc-objs
+    ../gcc-${gcc-unwrapped.version}/configure \
+      --with-native-system-header-dir=/include \
+      --with-build-sysroot=${lib.getDev glibc} \
+      --prefix=$out \
+      --enable-languages=c,vhdl \
+      --disable-bootstrap \
+      --disable-lto \
+      --disable-multilib \
+      --disable-libssp \
+      --disable-libgomp \
+      --disable-libquadmath
+    make -j $NIX_BUILD_CORES
+    make install
+    cd ../
+    make -j $NIX_BUILD_CORES ghdllib
+  '';
+
+  postFixup = lib.optionalString (backend == "gcc") ''
+    wrapProgram $out/bin/ghdl \
+      --set LIBRARY_PATH ${lib.makeLibraryPath [
+        glibc
+      ]}
+  '';
+
+  hardeningDisable = [
+  ] ++ lib.optionals (backend == "gcc") [
+    # GCC compilation fails with format errors
+    "format"
+  ];
+
+  enableParallelBuilding = true;
+
+  passthru = {
+    # run with:
+    # nix-build -A ghdl-mcode.passthru.tests
+    # nix-build -A ghdl-llvm.passthru.tests
+    # nix-build -A ghdl-gcc.passthru.tests
+    tests = {
+      simple = callPackage ./test-simple.nix { inherit backend; };
+    };
+  };
+
+  meta = {
+    homepage = "https://github.com/ghdl/ghdl";
+    description = "VHDL 2008/93/87 simulator";
+    license = lib.licenses.gpl2Plus;
+    mainProgram = "ghdl";
+    maintainers = with lib.maintainers; [ lucus16 thoughtpolice ];
+    platforms = lib.platforms.all;
+  };
+})