Merge pull request #74090 from obsidiansystems/ghcjs-cross-without-cc

stdenv, haskell: bonafied GHCJS cross compilation without stdenv.cc

3 files changed, 30 insertions, 7 deletions

diff --git a/pkgs/stdenv/booter.nix b/pkgs/stdenv/booter.nix
index 1df05099fbf..51d617354e8 100644
--- a/pkgs/stdenv/booter.nix
+++ b/pkgs/stdenv/booter.nix
@@ -121,9 +121,16 @@ stageFuns: let
   postStage = buildPackages: {
     __raw = true;
     stdenv.cc =
-      if buildPackages.stdenv.cc.isClang or false
-      then buildPackages.clang
-      else buildPackages.gcc;
+      if buildPackages.stdenv.hasCC
+      then
+        if buildPackages.stdenv.cc.isClang or false
+        then buildPackages.clang
+        else buildPackages.gcc
+      else
+        # This will blow up if anything uses it, but that's OK. The `if
+        # buildPackages.stdenv.cc.isClang then ... else ...` would blow up
+        # everything, so we make sure to avoid that.
+        buildPackages.stdenv.cc;
   };
 
 in dfold folder postStage (_: {}) withAllowCustomOverrides
diff --git a/pkgs/stdenv/cross/default.nix b/pkgs/stdenv/cross/default.nix
index 4e5c4cc2e83..cc49af7de3b 100644
--- a/pkgs/stdenv/cross/default.nix
+++ b/pkgs/stdenv/cross/default.nix
@@ -51,12 +51,18 @@ in lib.init bootStages ++ [
       extraBuildInputs = [ ]; # Old ones run on wrong platform
       allowedRequisites = null;
 
+      hasCC = !targetPlatform.isGhcjs;
+
       cc = if crossSystem.useiOSPrebuilt or false
              then buildPackages.darwin.iosSdkPkgs.clang
            else if crossSystem.useAndroidPrebuilt or false
              then buildPackages."androidndkPkgs_${crossSystem.ndkVer}".clang
            else if targetPlatform.isGhcjs
-             then null
+             # Need to use `throw` so tryEval for splicing works, ugh.  Using
+             # `null` or skipping the attribute would cause an eval failure
+             # `tryEval` wouldn't catch, wrecking accessing previous stages
+             # when there is a C compiler and everything should be fine.
+             then throw "no C compiler provided for this platform"
            else if crossSystem.useLLVM or false
              then buildPackages.llvmPackages_8.lldClang
            else buildPackages.gcc;
diff --git a/pkgs/stdenv/generic/default.nix b/pkgs/stdenv/generic/default.nix
index 2f43db9cfc2..befeb450997 100644
--- a/pkgs/stdenv/generic/default.nix
+++ b/pkgs/stdenv/generic/default.nix
@@ -1,6 +1,15 @@
 let lib = import ../../../lib; in lib.makeOverridable (
 
-{ name ? "stdenv", preHook ? "", initialPath, cc, shell
+{ name ? "stdenv", preHook ? "", initialPath
+
+, # If we don't have a C compiler, we might either have `cc = null` or `cc =
+  # throw ...`, but if we do have a C compiler we should definiely have `cc !=
+  # null`.
+  #
+  # TODO(@Ericson2314): Add assert without creating infinite recursion
+  hasCC ? cc != null, cc
+
+, shell
 , allowedRequisites ? null, extraAttrs ? {}, overrides ? (self: super: {}), config
 
 , # The `fetchurl' to use for downloading curl and its dependencies
@@ -57,7 +66,8 @@ let
       ../../build-support/setup-hooks/move-sbin.sh
       ../../build-support/setup-hooks/move-lib64.sh
       ../../build-support/setup-hooks/set-source-date-epoch-to-latest.sh
-      cc
+      # TODO use lib.optional instead
+      (if hasCC then cc else null)
     ];
 
   defaultBuildInputs = extraBuildInputs;
@@ -145,7 +155,7 @@ let
 
       inherit overrides;
 
-      inherit cc;
+      inherit cc hasCC;
     }
 
     # Propagate any extra attributes.  For instance, we use this to