haskellPackages.ghc not available on aarch64

[thefloweringash]

On current master (74e9b17).

nix-build -A haskellPackages.ghc

Fails with

[1 of 1] Compiling Main             ( Setup.hs, /build/Main.o )

<no location info>: error:
    Warning: Couldn't figure out LLVM version!
             Make sure you have installed LLVM 3.9

<no location info>: error: ghc: could not execute: opt

builder for '/nix/store/dazj2j2ccmg1kklfgn5igl77v7sbxk7m-hscolour-1.24.4.drv' failed with exit code 1

See also the full log.

Additional context

The hscolour derivation mentioned here does not contain llvm in its buildInputs. It seems sufficient to make llvm be a propagated build input for ghc-8.2.2-binary, after doing so I can build ghc itself.

diff --git a/pkgs/development/compilers/ghc/8.2.2-binary.nix b/pkgs/development/compilers/ghc/8.2.2-binary.nix
index 1f24b9a1ff2..bd1b8833087 100644
--- a/pkgs/development/compilers/ghc/8.2.2-binary.nix
+++ b/pkgs/development/compilers/ghc/8.2.2-binary.nix
@@ -53,7 +53,7 @@ stdenv.mkDerivation rec {
     or (throw "cannot bootstrap GHC on this platform"));
 
   nativeBuildInputs = [ perl ];
-  buildInputs = stdenv.lib.optionals (stdenv.targetPlatform.isAarch32 || stdenv.targetPlatform.isAarch64) [ llvm ];
+  propagatedBuildInputs = stdenv.lib.optionals (stdenv.targetPlatform.isAarch32 || stdenv.targetPlatform.isAarch64) [ llvm ];
 
   # Cannot patchelf beforehand due to relative RPATHs that anticipate
   # the final install location/

There's a lot of

You are using an unsupported version of LLVM!
Currently only 3.9 is supported.

Metadata

 - system: `"aarch64-linux"`
 - host os: `Linux 4.19.68, NixOS, 19.09.2070.b9cb3b2fb2f (Loris)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.3.2`
 - channels(root): `"nixos-19.09.2070.b9cb3b2fb2f"`
 - channels(lorne): `""`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

Maintainer information:

attribute: haskellPackages.ghc

[cdepillabout]

@thefloweringash Can you send a PR fixing this?

[thefloweringash]

@thefloweringash Can you send a PR fixing this?

Done, see #80355

[vcunat]

• port to release-20.03

[thefloweringash]

Since this issue was opened the situation has changed. There's still no ghc on aarch64, but now it fails due to the lack of aarch64 support in bootPkgs (aka ghc863Binary).

[vcunat]

After PR #83048 the default ghc builds for aarch64 (8c06685, ATM only in haskell-updates branch).