Take another route, use on older nixpkgs with llvm-12

cabal.project

@@ -156,10 +156,11 @@ source-repository-package
     location: https://github.com/chessai/eigen.git
     tag: 1790fdf9138970dde0dbabf8b270698145a4a88c
 
+-- llvm-12 with support for GHC 9.4.*
 source-repository-package
     type: git
     location: https://github.com/adinapoli/llvm-hs.git
-    tag: 787dddc034c94fbe5322b3a3c766c153c9259306
+    tag: 7533a9ccd3bfe77141745f6b61039a26aaf5c83b
     subdir: llvm-hs-pure
 
 source-repository-package

nix/overlays/ghc947.nix

+# DO NOT port this expression to hadrian. It is not possible to build a GHC
+# cross compiler with 9.4.* and hadrian.
+{ lib, stdenv, pkgsBuildTarget, pkgsHostTarget, targetPackages
+
+# build-tools
+, bootPkgs
+, autoconf, automake, coreutils, fetchpatch, fetchurl, perl, python3, m4, sphinx
+, xattr, autoSignDarwinBinariesHook
+, bash
+
+, libiconv ? null, ncurses
+, glibcLocales ? null
+
+, # GHC can be built with system libffi or a bundled one.
+  libffi ? null
+
+, useLLVM ? !(stdenv.targetPlatform.isx86
+              || stdenv.targetPlatform.isPower
+              || stdenv.targetPlatform.isSparc
+              || stdenv.targetPlatform.isAarch64)
+, # LLVM is conceptually a run-time-only dependency, but for
+  # non-x86, we need LLVM to bootstrap later stages, so it becomes a
+  # build-time dependency too.
+  buildTargetLlvmPackages, llvmPackages
+
+, # If enabled, GHC will be built with the GPL-free but slightly slower native
+  # bignum backend instead of the faster but GPLed gmp backend.
+  enableNativeBignum ? !(lib.meta.availableOn stdenv.hostPlatform gmp
+                         && lib.meta.availableOn stdenv.targetPlatform gmp)
+, gmp
+
+, # If enabled, use -fPIC when compiling static libs.
+  enableRelocatedStaticLibs ? stdenv.targetPlatform != stdenv.hostPlatform
+
+, enableProfiledLibs ? true
+
+, # Whether to build dynamic libs for the standard library (on the target
+  # platform). Static libs are always built.
+  enableShared ? with stdenv.targetPlatform; !isWindows && !useiOSPrebuilt && !isStatic
+
+, # Whether to build terminfo.
+  enableTerminfo ? !stdenv.targetPlatform.isWindows
+
+, # What flavour to build. An empty string indicates no
+  # specific flavour and falls back to ghc default values.
+  ghcFlavour ? lib.optionalString (stdenv.targetPlatform != stdenv.hostPlatform)
+    (if useLLVM then "perf-cross" else "perf-cross-ncg")
+
+, #  Whether to build sphinx documentation.
+  enableDocs ? (
+    # Docs disabled for musl and cross because it's a large task to keep
+    # all `sphinx` dependencies building in those environments.
+    # `sphinx` pulls in among others:
+    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
+    (stdenv.targetPlatform == stdenv.hostPlatform)
+    && !stdenv.hostPlatform.isMusl
+  )
+
+, enableHaddockProgram ?
+    # Disabled for cross; see note [HADDOCK_DOCS].
+    (stdenv.targetPlatform == stdenv.hostPlatform)
+
+, # Whether to disable the large address space allocator
+  # necessary fix for iOS: https://www.reddit.com/r/haskell/comments/4ttdz1/building_an_osxi386_to_iosarm64_cross_compiler/d5qvd67/
+  disableLargeAddressSpace ? stdenv.targetPlatform.isiOS
+}:
+
+assert !enableNativeBignum -> gmp != null;
+
+# Cross cannot currently build the `haddock` program for silly reasons,
+# see note [HADDOCK_DOCS].
+assert (stdenv.targetPlatform != stdenv.hostPlatform) -> !enableHaddockProgram;
+
+let
+  inherit (stdenv) buildPlatform hostPlatform targetPlatform;
+
+  inherit (bootPkgs) ghc;
+
+  # TODO(@Ericson2314) Make unconditional
+  targetPrefix = lib.optionalString
+    (targetPlatform != hostPlatform)
+    "${targetPlatform.config}-";
+
+  buildMK = ''
+    BuildFlavour = ${ghcFlavour}
+    ifneq \"\$(BuildFlavour)\" \"\"
+    include mk/flavours/\$(BuildFlavour).mk
+    endif
+    BUILD_SPHINX_HTML = ${if enableDocs then "YES" else "NO"}
+    BUILD_SPHINX_PDF = NO
+  '' +
+  # Note [HADDOCK_DOCS]:
+  # Unfortunately currently `HADDOCK_DOCS` controls both whether the `haddock`
+  # program is built (which we generally always want to have a complete GHC install)
+  # and whether it is run on the GHC sources to generate hyperlinked source code
+  # (which is impossible for cross-compilation); see:
+  # https://gitlab.haskell.org/ghc/ghc/-/issues/20077
+  # This implies that currently a cross-compiled GHC will never have a `haddock`
+  # program, so it can never generate haddocks for any packages.
+  # If this is solved in the future, we'd like to unconditionally
+  # build the haddock program (removing the `enableHaddockProgram` option).
+  ''
+    HADDOCK_DOCS = ${if enableHaddockProgram then "YES" else "NO"}
+    # Build haddocks for boot packages with hyperlinking
+    EXTRA_HADDOCK_OPTS += --hyperlinked-source --quickjump
+
+    DYNAMIC_GHC_PROGRAMS = ${if enableShared then "YES" else "NO"}
+    BIGNUM_BACKEND = ${if enableNativeBignum then "native" else "gmp"}
+  '' + lib.optionalString (targetPlatform != hostPlatform) ''
+    Stage1Only = ${if targetPlatform.system == hostPlatform.system then "NO" else "YES"}
+    CrossCompilePrefix = ${targetPrefix}
+  '' + lib.optionalString (!enableProfiledLibs) ''
+    GhcLibWays = "v dyn"
+  '' +
+  # -fexternal-dynamic-refs apparently (because it's not clear from the documentation)
+  # makes the GHC RTS able to load static libraries, which may be needed for TemplateHaskell.
+  # This solution was described in https://www.tweag.io/blog/2020-09-30-bazel-static-haskell
+  lib.optionalString enableRelocatedStaticLibs ''
+    GhcLibHcOpts += -fPIC -fexternal-dynamic-refs
+    GhcRtsHcOpts += -fPIC -fexternal-dynamic-refs
+  '' + lib.optionalString targetPlatform.useAndroidPrebuilt ''
+    EXTRA_CC_OPTS += -std=gnu99
+  '';
+
+  # Splicer will pull out correct variations
+  libDeps = platform: lib.optional enableTerminfo ncurses
+    ++ [libffi]
+    ++ lib.optional (!enableNativeBignum) gmp
+    ++ lib.optional (platform.libc != "glibc" && !targetPlatform.isWindows) libiconv;
+
+  # TODO(@sternenseemann): is buildTarget LLVM unnecessary?
+  # GHC doesn't seem to have {LLC,OPT}_HOST
+  toolsForTarget = [
+    pkgsBuildTarget.targetPackages.stdenv.cc
+  ] ++ lib.optional useLLVM buildTargetLlvmPackages.llvm;
+
+  targetCC = builtins.head toolsForTarget;
+
+  # Sometimes we have to dispatch between the bintools wrapper and the unwrapped
+  # derivation for certain tools depending on the platform.
+  bintoolsFor = {
+    # GHC needs install_name_tool on all darwin platforms. On aarch64-darwin it is
+    # part of the bintools wrapper (due to codesigning requirements), but not on
+    # x86_64-darwin.
+    install_name_tool =
+      if stdenv.targetPlatform.isAarch64
+      then targetCC.bintools
+      else targetCC.bintools.bintools;
+    # Same goes for strip.
+    strip =
+      # TODO(@sternenseemann): also use wrapper if linker == "bfd" or "gold"
+      if stdenv.targetPlatform.isAarch64 && stdenv.targetPlatform.isDarwin
+      then targetCC.bintools
+      else targetCC.bintools.bintools;
+  };
+
+  # Use gold either following the default, or to avoid the BFD linker due to some bugs / perf issues.
+  # But we cannot avoid BFD when using musl libc due to https://sourceware.org/bugzilla/show_bug.cgi?id=23856
+  # see #84670 and #49071 for more background.
+  useLdGold = targetPlatform.linker == "gold" ||
+    (targetPlatform.linker == "bfd" && (targetCC.bintools.bintools.hasGold or false) && !targetPlatform.isMusl);
+
+  # Makes debugging easier to see which variant is at play in `nix-store -q --tree`.
+  variantSuffix = lib.concatStrings [
+    (lib.optionalString stdenv.hostPlatform.isMusl "-musl")
+    (lib.optionalString enableNativeBignum "-native-bignum")
+  ];
+
+in
+
+# C compiler, bintools and LLVM are used at build time, but will also leak into
+# the resulting GHC's settings file and used at runtime. This means that we are
+# currently only able to build GHC if hostPlatform == buildPlatform.
+assert targetCC == pkgsHostTarget.targetPackages.stdenv.cc;
+assert buildTargetLlvmPackages.llvm == llvmPackages.llvm;
+assert stdenv.targetPlatform.isDarwin -> buildTargetLlvmPackages.clang == llvmPackages.clang;
+
+stdenv.mkDerivation (rec {
+  version = "9.4.7";
+  pname = "${targetPrefix}ghc${variantSuffix}";
+
+  src = fetchurl {
+    url = "https://downloads.haskell.org/ghc/${version}/ghc-${version}-src.tar.xz";
+    sha256 = "06775a52b4d13ac09edc6dabc299fd11e59d8886bbcae450af367baee2684c8f";
+  };
+
+  enableParallelBuilding = true;
+
+  outputs = [ "out" "doc" ];
+
+  patches = [
+    # Don't generate code that doesn't compile when --enable-relocatable is passed to Setup.hs
+    # Can be removed if the Cabal library included with ghc backports the linked fix
+    (fetchpatch {
+      url = "https://github.com/haskell/cabal/commit/6c796218c92f93c95e94d5ec2d077f6956f68e98.patch";
+      stripLen = 1;
+      extraPrefix = "libraries/Cabal/";
+      sha256 = "sha256-yRQ6YmMiwBwiYseC5BsrEtDgFbWvst+maGgDtdD0vAY=";
+    })
+
+  ] ++ lib.optionals (stdenv.targetPlatform.isDarwin && stdenv.targetPlatform.isAarch64) [
+    # Prevent the paths module from emitting symbols that we don't use
+    # when building with separate outputs.
+    #
+    # These cause problems as they're not eliminated by GHC's dead code
+    # elimination on aarch64-darwin. (see
+    # https://github.com/NixOS/nixpkgs/issues/140774 for details).
+    ./Cabal-3.6-3.8-paths-fix-cycle-aarch64-darwin.patch
+  ] ++ (if stdenv.isDarwin
+           then [ # Reverts the linking behavior of GHC to not resolve `-libc++` to `c++`.
+                    (fetchpatch {
+                      url = "https://gist.githubusercontent.com/adinapoli/bf722db15f72763bf79dff13a3104b6f/raw/21e4fe65e71e721aece563b0c39be6ba1ace5b28/ghc947-macOS-loadArchive-fix.patch";
+                      sha256 = "sha256-0rWN6nGIVlB65QBGX3PaHPQFCitGGC8wTJg8kPJu5KQ=";
+                    })
+                ]
+           else []);
+
+  postPatch = "patchShebangs .";
+
+  # GHC needs the locale configured during the Haddock phase.
+  LANG = "en_US.UTF-8";
+
+  # GHC is a bit confused on its cross terminology.
+  # TODO(@sternenseemann): investigate coreutils dependencies and pass absolute paths
+  preConfigure = ''
+    for env in $(env | grep '^TARGET_' | sed -E 's|\+?=.*||'); do
+      export "''${env#TARGET_}=''${!env}"
+    done
+    # GHC is a bit confused on its cross terminology, as these would normally be
+    # the *host* tools.
+    export CC="${targetCC}/bin/${targetCC.targetPrefix}cc"
+    export CXX="${targetCC}/bin/${targetCC.targetPrefix}c++"
+    # Use gold to work around https://sourceware.org/bugzilla/show_bug.cgi?id=16177
+    export LD="${targetCC.bintools}/bin/${targetCC.bintools.targetPrefix}ld${lib.optionalString useLdGold ".gold"}"
+    export AS="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}as"
+    export AR="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}ar"
+    export NM="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}nm"
+    export RANLIB="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}ranlib"
+    export READELF="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}readelf"
+    export STRIP="${bintoolsFor.strip}/bin/${bintoolsFor.strip.targetPrefix}strip"
+  '' + lib.optionalString (stdenv.targetPlatform.linker == "cctools") ''
+    export OTOOL="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}otool"
+    export INSTALL_NAME_TOOL="${bintoolsFor.install_name_tool}/bin/${bintoolsFor.install_name_tool.targetPrefix}install_name_tool"
+  '' + lib.optionalString useLLVM ''
+    export LLC="${lib.getBin buildTargetLlvmPackages.llvm}/bin/llc"
+    export OPT="${lib.getBin buildTargetLlvmPackages.llvm}/bin/opt"
+  '' + lib.optionalString (useLLVM && stdenv.targetPlatform.isDarwin) ''
+    # LLVM backend on Darwin needs clang: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/codegens.html#llvm-code-generator-fllvm
+    export CLANG="${buildTargetLlvmPackages.clang}/bin/${buildTargetLlvmPackages.clang.targetPrefix}clang"
+  '' + ''
+
+    echo -n "${buildMK}" > mk/build.mk
+
+    sed -i -e 's|-isysroot /Developer/SDKs/MacOSX10.5.sdk||' configure
+  '' + lib.optionalString (stdenv.isLinux && hostPlatform.libc == "glibc") ''
+    export LOCALE_ARCHIVE="${glibcLocales}/lib/locale/locale-archive"
+  '' + lib.optionalString (!stdenv.isDarwin) ''
+    export NIX_LDFLAGS+=" -rpath $out/lib/ghc-${version}"
+  '' + lib.optionalString stdenv.isDarwin ''
+    export NIX_LDFLAGS+=" -no_dtrace_dof"
+
+    # GHC tries the host xattr /usr/bin/xattr by default which fails since it expects python to be 2.7
+    export XATTR=${lib.getBin xattr}/bin/xattr
+  '' + lib.optionalString targetPlatform.useAndroidPrebuilt ''
+    sed -i -e '5i ,("armv7a-unknown-linux-androideabi", ("e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64", "cortex-a8", ""))' llvm-targets
+  '' + lib.optionalString targetPlatform.isMusl ''
+      echo "patching llvm-targets for musl targets..."
+      echo "Cloning these existing '*-linux-gnu*' targets:"
+      grep linux-gnu llvm-targets | sed 's/^/  /'
+      echo "(go go gadget sed)"
+      sed -i 's,\(^.*linux-\)gnu\(.*\)$,\0\n\1musl\2,' llvm-targets
+      echo "llvm-targets now contains these '*-linux-musl*' targets:"
+      grep linux-musl llvm-targets | sed 's/^/  /'
+
+      echo "And now patching to preserve '-musleabi' as done with '-gnueabi'"
+      # (aclocal.m4 is actual source, but patch configure as well since we don't re-gen)
+      for x in configure aclocal.m4; do
+        substituteInPlace $x \
+          --replace '*-android*|*-gnueabi*)' \
+                    '*-android*|*-gnueabi*|*-musleabi*)'
+      done
+  ''
+  # HACK: allow bootstrapping with GHC 8.10 which works fine, as we don't have
+  # binary 9.0 packaged. Bootstrapping with 9.2 is broken without hadrian.
+  + ''
+    substituteInPlace configure --replace \
+      'MinBootGhcVersion="9.0"' \
+      'MinBootGhcVersion="8.10"'
+  '';
+
+  # TODO(@Ericson2314): Always pass "--target" and always prefix.
+  configurePlatforms = [ "build" "host" ]
+    ++ lib.optional (targetPlatform != hostPlatform) "target";
+
+  # `--with` flags for libraries needed for RTS linker
+  configureFlags = [
+    "--datadir=$doc/share/doc/ghc"
+    "--with-curses-includes=${ncurses.dev}/include" "--with-curses-libraries=${ncurses.out}/lib"
+  ] ++ lib.optionals (libffi != null) [
+    "--with-system-libffi"
+    "--with-ffi-includes=${targetPackages.libffi.dev}/include"
+    "--with-ffi-libraries=${targetPackages.libffi.out}/lib"
+  ] ++ lib.optionals (targetPlatform == hostPlatform && !enableNativeBignum) [
+    "--with-gmp-includes=${targetPackages.gmp.dev}/include"
+    "--with-gmp-libraries=${targetPackages.gmp.out}/lib"
+  ] ++ lib.optionals (targetPlatform == hostPlatform && hostPlatform.libc != "glibc" && !targetPlatform.isWindows) [
+    "--with-iconv-includes=${libiconv}/include"
+    "--with-iconv-libraries=${libiconv}/lib"
+  ] ++ lib.optionals (targetPlatform != hostPlatform) [
+    "--enable-bootstrap-with-devel-snapshot"
+  ] ++ lib.optionals useLdGold [
+    "CFLAGS=-fuse-ld=gold"
+    "CONF_GCC_LINKER_OPTS_STAGE1=-fuse-ld=gold"
+    "CONF_GCC_LINKER_OPTS_STAGE2=-fuse-ld=gold"
+  ] ++ lib.optionals (disableLargeAddressSpace) [
+    "--disable-large-address-space"
+  ];
+
+  # Make sure we never relax`$PATH` and hooks support for compatibility.
+  strictDeps = true;
+
+  # Don’t add -liconv to LDFLAGS automatically so that GHC will add it itself.
+  dontAddExtraLibs = true;
+
+  nativeBuildInputs = [
+    perl autoconf automake m4 python3
+    ghc bootPkgs.alex bootPkgs.happy bootPkgs.hscolour
+  ] ++ lib.optionals (stdenv.isDarwin && stdenv.isAarch64) [
+    autoSignDarwinBinariesHook
+  ] ++ lib.optionals enableDocs [
+    sphinx
+  ];
+
+  # For building runtime libs
+  depsBuildTarget = toolsForTarget;
+
+  buildInputs = [ perl bash ] ++ (libDeps hostPlatform);
+
+  depsTargetTarget = map lib.getDev (libDeps targetPlatform);
+  depsTargetTargetPropagated = map (lib.getOutput "out") (libDeps targetPlatform);
+
+  # required, because otherwise all symbols from HSffi.o are stripped, and
+  # that in turn causes GHCi to abort
+  stripDebugFlags = [ "-S" ] ++ lib.optional (!targetPlatform.isDarwin) "--keep-file-symbols";
+
+  checkTarget = "test";
+
+  hardeningDisable =
+    [ "format" ]
+    # In nixpkgs, musl based builds currently enable `pie` hardening by default
+    # (see `defaultHardeningFlags` in `make-derivation.nix`).
+    # But GHC cannot currently produce outputs that are ready for `-pie` linking.
+    # Thus, disable `pie` hardening, otherwise `recompile with -fPIE` errors appear.
+    # See:
+    # * https://github.com/NixOS/nixpkgs/issues/129247
+    # * https://gitlab.haskell.org/ghc/ghc/-/issues/19580
+    ++ lib.optional stdenv.targetPlatform.isMusl "pie";
+
+  # big-parallel allows us to build with more than 2 cores on
+  # Hydra which already warrants a significant speedup
+  requiredSystemFeatures = [ "big-parallel" ];
+
+  postInstall = ''
+    # Install the bash completion file.
+    install -D -m 444 utils/completion/ghc.bash $out/share/bash-completion/completions/${targetPrefix}ghc
+  '';
+
+  passthru = {
+    inherit bootPkgs targetPrefix;
+
+    inherit llvmPackages;
+    inherit enableShared;
+
+    # This is used by the haskell builder to query
+    # the presence of the haddock program.
+    hasHaddock = enableHaddockProgram;
+
+    # Our Cabal compiler name
+    haskellCompilerName = "ghc-${version}";
+  };
+
+  meta = {
+    homepage = "http://haskell.org/ghc";
+    description = "The Glasgow Haskell Compiler";
+    maintainers = with lib.maintainers; [
+      guibou
+    ] ++ lib.teams.haskell.members;
+    timeout = 24 * 3600;
+    inherit (ghc.meta) license platforms;
+  };
+
+} // lib.optionalAttrs targetPlatform.useAndroidPrebuilt {
+  dontStrip = true;
+  dontPatchELF = true;
+  noAuditTmpdir = true;
+})

nix/pinned-23.05.nix

+import (builtins.fetchGit {
+  name = "nixos-23.05";
+  url = "https://github.com/nixos/nixpkgs";
+  ref = "refs/heads/nixos-23.05";
+  rev = "4ecab3273592f27479a583fb6d975d4aba3486fe";
+})

nix/pkgs.nix

-{ pkgs       ? import ./pinned-23.11.nix {} }:
+{ pkgs       ? import ./pinned-23.05.nix {} }:
 
 rec {
   inherit pkgs;
-  # If we are on a Mac, in order to build successfully with cabal we need a bit more work.
-  ghc = if pkgs.stdenv.isDarwin
-           then haskell1.compiler.ghc947.overrideAttrs (finalAttrs: previousAttrs: {
-                # See https://github.com/NixOS/nixpkgs/pull/149942/files
-                patches = previousAttrs.patches ++ [
-                            # Reverts the linking behavior of GHC to not resolve `-libc++` to `c++`.
-                            (pkgs.fetchpatch {
-                              url = "https://gist.githubusercontent.com/adinapoli/bf722db15f72763bf79dff13a3104b6f/raw/21e4fe65e71e721aece563b0c39be6ba1ace5b28/ghc947-macOS-loadArchive-fix.patch";
-                              sha256 = "sha256-0rWN6nGIVlB65QBGX3PaHPQFCitGGC8wTJg8kPJu5KQ=";
-                            })
-                          ];
-                })
-           else pkgs.haskell.compiler.ghc947;
-  haskell1 = pkgs.haskell // {
-      packages = pkgs.haskell.packages // {
-        ghc947 = pkgs.haskell.packages.ghc947.override {
-          overrides = self: super: {
-            #directory            = self.callPackage ./overlays/directory-1.3.7.1.nix {};
-            #process              = self.callPackage ./overlays/process-1.6.17.0.nix {};
-            #hackage-security     = self.callPackage ./overlays/hackage-security-0.6.2.3.nix {};
-            #Cabal                = self.callPackage ./overlays/Cabal-3.10.1.0.nix {};
-            #Cabal-syntax         = self.callPackage ./overlays/Cabal-syntax-3.10.1.0.nix {};
-            #cabal-install-solver = self.callPackage ./overlays/cabal-install-solver-3.10.1.0.nix {};
-            #cabal-install        = self.callPackage ./overlays/cabal-install-3.10.1.0.nix {};
-          };
-        };
-      };
+  ghc947 = pkgs.callPackage ./overlays/ghc947.nix {
+      bootPkgs = pkgs.haskell.packages.ghc8107;
+      inherit (pkgs.buildPackages.python3Packages) sphinx;
+      # Need to use apple's patched xattr until
+      # https://github.com/xattr/xattr/issues/44 and
+      # https://github.com/xattr/xattr/issues/55 are solved.
+      inherit (pkgs.buildPackages.darwin) xattr autoSignDarwinBinariesHook;
+      buildTargetLlvmPackages = pkgs.pkgsBuildTarget.llvmPackages_12;
+      llvmPackages = pkgs.llvmPackages_12;
   };
   #cabal_install_3_10_1_0 = pkgs.haskell.lib.compose.justStaticExecutables haskell1.packages.ghc947.cabal-install;
   graphviz = pkgs.graphviz.overrideAttrs (finalAttrs: previousAttrs: {
@@ -44,7 +26,7 @@ rec {
   igraph_0_10_4 = pkgs.igraph.overrideAttrs (finalAttrs: previousAttrs: {
     version = "0.10.4";
 
-    nativeBuildInputs = previousAttrs.nativeBuildInputs or [] ++ [ pkgs.gcc7 pkgs.clang_11 ];
+    nativeBuildInputs = previousAttrs.nativeBuildInputs or [] ++ [ pkgs.clang_12 ];
 
     src = pkgs.fetchFromGitHub {
       owner = "igraph";
@@ -99,7 +81,7 @@ rec {
 
   });
   hsBuildInputs = [
-    ghc
+    ghc947
     #cabal_install_3_10_1_0
   ];
   nonhsBuildInputs = with pkgs; [
@@ -121,12 +103,11 @@ rec {
     zlib
     blas
     gfortran7
-    #    gfortran7.cc.lib
     expat
     icu
     graphviz
-    llvm_11
-    clang_11
+    llvm_12
+    clang_12
     gcc7
     igraph_0_10_4
     libpqxx