1 files changed, 53 insertions, 9 deletions

diff --git a/pkgs/development/compilers/ghc/8.8.4.nix b/pkgs/development/compilers/ghc/8.8.4.nix
index 544b96f5e4f..23826614716 100644
--- a/pkgs/development/compilers/ghc/8.8.4.nix
+++ b/pkgs/development/compilers/ghc/8.8.4.nix
@@ -38,6 +38,20 @@
   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` pullls 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.isDarwin && stdenv.targetPlatform.isAarch64
@@ -45,6 +59,10 @@
 
 assert !enableIntegerSimple -> 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;
 
@@ -60,6 +78,21 @@ let
     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"}
     DYNAMIC_GHC_PROGRAMS = ${if enableShared then "YES" else "NO"}
     INTEGER_LIBRARY = ${if enableIntegerSimple then "integer-simple" else "integer-gmp"}
   ''
@@ -72,9 +105,6 @@ let
   + lib.optionalString (targetPlatform != hostPlatform) ''
     Stage1Only = ${if (targetPlatform.system == hostPlatform.system && !targetPlatform.isiOS) then "NO" else "YES"}
     CrossCompilePrefix = ${targetPrefix}
-    HADDOCK_DOCS = NO
-    BUILD_SPHINX_HTML = NO
-    BUILD_SPHINX_PDF = NO
   '' + lib.optionalString dontStrip ''
     STRIP_CMD = :
   '' + lib.optionalString (!enableProfiledLibs) ''
@@ -142,11 +172,14 @@ stdenv.mkDerivation (rec {
   postPatch = "patchShebangs .";
 
   # GHC is a bit confused on its cross terminology.
-  preConfigure = lib.optionalString stdenv.isAarch64 ''
+  preConfigure =
     # Aarch64 allow backward bootstrapping since earlier versions are unstable.
-    find . -name \*\.cabal\* -exec sed -i -e 's/\(base.*\)4.14/\14.16/' {} \; \
-      -exec sed -i -e 's/\(prim.*\)0.6/\10.8/' {} \;
-  '' + ''
+    # Same for musl, as earlier versions do not provide a musl bindist for bootstrapping.
+    lib.optionalString (stdenv.isAarch64 || stdenv.hostPlatform.isMusl) ''
+      find . -name \*\.cabal\* -exec sed -i -e 's/\(base.*\)4.14/\14.16/' {} \; \
+        -exec sed -i -e 's/\(prim.*\)0.6/\10.8/' {} \;
+    ''
+  + ''
     for env in $(env | grep '^TARGET_' | sed -E 's|\+?=.*||'); do
       export "''${env#TARGET_}=''${!env}"
     done
@@ -224,8 +257,10 @@ stdenv.mkDerivation (rec {
   dontAddExtraLibs = true;
 
   nativeBuildInputs = [
-    perl autoconf automake m4 python3 sphinx
+    perl autoconf automake m4 python3
     ghc bootPkgs.alex bootPkgs.happy bootPkgs.hscolour
+  ] ++ lib.optionals enableDocs [
+    sphinx
   ];
 
   # For building runtime libs
@@ -245,7 +280,16 @@ stdenv.mkDerivation (rec {
 
   checkTarget = "test";
 
-  hardeningDisable = [ "format" ] ++ lib.optional stdenv.targetPlatform.isMusl "pie";
+  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";
 
   postInstall = ''
     # Install the bash completion file.