+ private llvm build, compiles.

pkgs/llvm.nix

@@ -0,0 +1,113 @@
+{
+  lib,
+
+  stdenv, cmake, python3,
+
+  enableSharedLibraries ? !stdenv.hostPlatform.isStatic,
+
+  libxml2, libffi, libedit, ncurses, zlib,
+
+  fetchFromGitHub,
+} :
+
+let
+  version = "18.1.7";
+
+  src = fetchFromGitHub {
+    name = "llvm-${version}-source";
+    owner = "llvm";
+    repo = "llvm-project";
+    rev = "llvmorg-${version}";
+    hash = "sha256-qBL/1zh2YFabiPAyHehvzDSDfnwnCvyH6nY/pzG757A=";
+  };
+
+  defaultTargets =
+    if stdenv.hostPlatform.isAarch64 then "AArch64"
+    else if stdenv.hostPlatform.isx86 then "X86"
+    else "all";
+
+in {
+  # running out of memory during linking!!
+
+  llvm = stdenv.mkDerivation (finalAttrs:
+    {
+      pname = "llvm-xo";
+      inherit version src;
+
+      # only taking llvm subdir from upstream repo
+      sourceRoot = "${src.name}/llvm";
+
+      outputs = [ "out" ];
+
+      nativeBuildInputs = [ cmake python3 ];
+
+      #NIX_CFLAGS_LINK = "-Wl,--no-keep-memory, -Wl,--reduce-memory-overheads";
+      #NIX_CFLAGS_LINK = "-fuse-ld=gold"; # or -fuse-ld=lld
+
+      buildInputs = [ libxml2
+                      libffi
+                      zlib
+                      ncurses
+                      libedit
+      ];
+
+      propagatedBuildInputs = [ ncurses zlib ];
+
+      cmakeFlags = [
+        "-DCMAKE_BUILD_TYPE=Release"
+
+        "-DLLVM_TARGETS_TO_BUILD=${defaultTargets}"
+
+        "-DLLVM_BUILD_LLVM_DYLIB=${lib.boolToString enableSharedLibraries}"
+        "-DLLVM_LINK_LLVM_DYLIB=${lib.boolToString enableSharedLibraries}"
+
+        # host configuration
+        "-DLLVM_INSTALL_CMAKE_DIR=${placeholder "bin"}/lib/cmake/llvm"
+        "-DLLVM_INSTALL_BINUTILS_SYMLINKS=OFF"
+
+      ];
+
+      buildFlags = [
+        "VERBOSE=1"
+        "-j 12"
+      ];
+
+      # running out of memory!
+      enableParallelBuilding = true;
+
+      # for llvm keep debug symbols
+      separateDebugInfo = stdenv.isLinux;
+
+      postInstall = ''
+        # create compatibility symlinks
+        mkdir -p $out/bin
+        for tool in llvm-config llvm-nm llvm-objdump llvm-readobj llvm-ar; do
+          ln -sf $out/bin/$tool $out/bin/${stdenv.hostPlatform.config}-$tool
+        done
+
+#        # dev related files to llvm.dev
+#        moveToOutput "lib/cmake" "$dev"
+#        moveToOutput "include" "$dev"
+#        moveToOutput "lib/*.a" "$dev"
+
+#        # move any shared libraries to llvm.lib
+#        mkdir -p $lib/lib
+#        mv $out/lib/*.so* $lib/lib/ || true
+      '';
+
+      passthru = {
+        inherit src;
+        isClang = false;
+        hardeningUnsupportedFlags = [ "fortify3" ];
+      };
+
+      meta = with lib; {
+        description = "A collection of modular and reusable compiler and toolchain technologies";
+        homepage = "https://llvm.org/";
+        license = lib.licenses.ncsa;
+        maintainers = with maintainers; [];
+        platforms = platforms.all;
+        broken = stdenv.hostPlatform.is32bit;
+      };
+    });
+}