linux: fix compiler selection (#402198)

pkgs/development/compilers/gcc/common/configure-flags.nix

···
   enablePlugin,
   disableGdbPlugin ? !enablePlugin,
   enableShared,
+  targetPrefix,
 
   langC,
   langCC,
···
   crossMingw = (!lib.systems.equals targetPlatform hostPlatform) && targetPlatform.isMinGW;
   crossDarwin =
     (!lib.systems.equals targetPlatform hostPlatform) && targetPlatform.libc == "libSystem";
-
-  targetPrefix = lib.optionalString (
-    !lib.systems.equals stdenv.targetPlatform stdenv.hostPlatform
-  ) "${stdenv.targetPlatform.config}-";
 
   crossConfigureFlags =
     # Ensure that -print-prog-name is able to find the correct programs.

pkgs/development/compilers/gcc/common/meta.nix

···
-{ lib, version }:
+{
+  lib,
+  version,
+  targetPrefix,
+}:
 
 let
   inherit (lib)
···
 
   platforms = platforms.unix;
   teams = [ teams.gcc ];
+  mainProgram = "${targetPrefix}gcc";
 
 }

pkgs/development/compilers/gcc/default.nix

···
     !lib.systems.equals targetPlatform hostPlatform
   ) "${targetPlatform.config}${stageNameAddon}-";
 
+  targetPrefix = lib.optionalString (
+    !lib.systems.equals stdenv.targetPlatform stdenv.hostPlatform
+  ) "${stdenv.targetPlatform.config}-";
+
   callFile = callPackageWith {
     # lets
     inherit
···
         "target"
       ];
 
-      configureFlags = callFile ./common/configure-flags.nix { };
+      configureFlags = callFile ./common/configure-flags.nix { inherit targetPrefix; };
 
       inherit targetConfig;
 
···
       inherit enableShared enableMultilib;
 
       meta = {
-        inherit (callFile ./common/meta.nix { })
+        inherit (callFile ./common/meta.nix { inherit targetPrefix; })
           homepage
           license
           description
           longDescription
           platforms
           teams
+          mainProgram
           ;
       }
       // optionalAttrs (!atLeast11) {

pkgs/development/compilers/zig/cc.nix

···
 runCommand "zig-cc-${zig.version}"
   {
     pname = "zig-cc";
-    inherit (zig) version meta;
+    inherit (zig) version;
 
     nativeBuildInputs = [ makeWrapper ];
 
···
     };
 
     inherit zig;
+
+    meta = zig.meta // {
+      mainProgram = "${targetPrefix}clang";
+    };
   }
   ''
     mkdir -p $out/bin

pkgs/os-specific/linux/kernel/common-config.nix

···
         DRM_AMD_DC_DCN = lib.mkIf (with stdenv.hostPlatform; isx86 || isPower64) (
           whenBetween "5.11" "6.4" yes
         );
-        DRM_AMD_DC_FP = whenAtLeast "6.4" yes;
+        # Not available when using clang
+        # See: https://github.com/torvalds/linux/blob/172a9d94339cea832d89630b89d314e41d622bd8/drivers/gpu/drm/amd/display/Kconfig#L14
+        DRM_AMD_DC_FP = lib.mkIf (!stdenv.cc.isClang) (whenAtLeast "6.4" yes);
         DRM_AMD_DC_HDCP = whenBetween "5.5" "6.4" yes;
         DRM_AMD_DC_SI = whenAtLeast "5.10" yes;
 

pkgs/os-specific/linux/kernel/common-flags.nix

···
+{
+  lib,
+  stdenv,
+  buildPackages,
+  extraMakeFlags ? [ ],
+}:
+# Absolute paths for compilers avoid any PATH-clobbering issues.
+[
+  #
+  # We use the unwrapped compiler, because the clang-wrapper doesn't like -target.
+  "CC=${lib.getExe stdenv.cc.cc}"
+  # The wrapper for ld.lld breaks linking the kernel. We use the unwrapped linker as workaround. See:
+  # https://github.com/NixOS/nixpkgs/issues/321667
+  "LD=${lib.getExe' stdenv.cc.bintools.bintools "${stdenv.cc.targetPrefix}ld"}"
+  "AR=${lib.getExe' stdenv.cc "${stdenv.cc.targetPrefix}ar"}"
+  "NM=${lib.getExe' stdenv.cc "${stdenv.cc.targetPrefix}nm"}"
+  "STRIP=${lib.getExe' stdenv.cc.bintools.bintools "${stdenv.cc.targetPrefix}strip"}"
+  "OBJCOPY=${lib.getExe' stdenv.cc "${stdenv.cc.targetPrefix}objcopy"}"
+  "OBJDUMP=${lib.getExe' stdenv.cc "${stdenv.cc.targetPrefix}objdump"}"
+  "READELF=${lib.getExe' stdenv.cc "${stdenv.cc.targetPrefix}readelf"}"
+  "HOSTCC=${lib.getExe' buildPackages.stdenv.cc "${buildPackages.stdenv.cc.targetPrefix}cc"}"
+  "HOSTCXX=${lib.getExe' buildPackages.stdenv.cc "${buildPackages.stdenv.cc.targetPrefix}c++"}"
+  "HOSTAR=${lib.getExe' buildPackages.stdenv.cc.bintools "${buildPackages.stdenv.cc.targetPrefix}ar"}"
+  "HOSTLD=${lib.getExe' buildPackages.stdenv.cc.bintools "${buildPackages.stdenv.cc.targetPrefix}ld"}"
+  "ARCH=${stdenv.hostPlatform.linuxArch}"
+  "CROSS_COMPILE=${stdenv.cc.targetPrefix}"
+]
+# Add the built in headers the kernel needs
+++ lib.optionals (stdenv.cc.isClang) [
+  "CFLAGS_MODULE=-I${lib.getLib stdenv.cc.cc}/lib/clang/${lib.versions.major stdenv.cc.cc.version}/include"
+  "CFLAGS_KERNEL=-I${lib.getLib stdenv.cc.cc}/lib/clang/${lib.versions.major stdenv.cc.cc.version}/include"
+]
+++ (stdenv.hostPlatform.linux-kernel.makeFlags or [ ])
+++ extraMakeFlags

pkgs/os-specific/linux/kernel/generic.nix

···
         ++ lib.optional (lib.versionAtLeast version "5.2") pahole
         ++ lib.optionals withRust [
           rust-bindgen
-          rustc
+          rustc.unwrapped
         ];
 
         RUST_LIB_SRC = lib.optionalString withRust rustPlatform.rustLibSrc;
···
         kernelBaseConfig =
           if defconfig != null then defconfig else stdenv.hostPlatform.linux-kernel.baseConfig;
 
-        makeFlags =
-          lib.optionals (
-            stdenv.hostPlatform.linux-kernel ? makeFlags
-          ) stdenv.hostPlatform.linux-kernel.makeFlags
-          ++ extraMakeFlags;
+        makeFlags = import ./common-flags.nix {
+          inherit
+            lib
+            stdenv
+            buildPackages
+            extraMakeFlags
+            ;
+        };
 
         postPatch = kernel.postPatch + ''
           # Patch kconfig to print "###" after every question so that
···
             KERNEL_CONFIG="$buildRoot/kernel-config" AUTO_MODULES=$autoModules \
             PREFER_BUILTIN=$preferBuiltin BUILD_ROOT="$buildRoot" SRC=. MAKE_FLAGS="$makeFlags" \
             perl -w $generateConfig
+        ''
+        + lib.optionalString stdenv.cc.isClang ''
+          if ! grep -Fq CONFIG_CC_IS_CLANG=y $buildRoot/.config; then
+            echo "Kernel config didn't recognize the clang compiler?"
+            exit 1
+          fi
+        ''
+        + lib.optionalString stdenv.cc.bintools.isLLVM ''
+          if ! grep -Fq CONFIG_LD_IS_LLD=y $buildRoot/.config; then
+            echo "Kernel config didn't recognize the LLVM linker?"
+            exit 1
+          fi
+        ''
+        + lib.optionalString withRust ''
+          if ! grep -Fq CONFIG_RUST_IS_AVAILABLE=y $buildRoot/.config; then
+            echo "Kernel config didn't find Rust toolchain?"
+            exit 1
+          fi
         '';
 
         installPhase = "mv $buildRoot/.config $out";

pkgs/os-specific/linux/kernel/manual-config.nix

···
         ++ optional (lib.versionAtLeast version "5.13") zstd
         ++ optionals withRust [
           rustc
-          rust-bindgen
+          rust-bindgen.unwrapped
         ];
 
       in
···
         ]
         ++ optionals withRust [
           rustc
-          rust-bindgen
+          rust-bindgen.unwrapped
         ];
 
         RUST_LIB_SRC = lib.optionalString withRust rustPlatform.rustLibSrc;
···
         // extraMeta;
       };
 
-    # Absolute paths for compilers avoid any PATH-clobbering issues.
-    commonMakeFlags = [
-      "ARCH=${stdenv.hostPlatform.linuxArch}"
-      "CROSS_COMPILE=${stdenv.cc.targetPrefix}"
-    ]
-    ++ lib.optionals (stdenv.isx86_64 && stdenv.cc.bintools.isLLVM) [
-      # The wrapper for ld.lld breaks linking the kernel. We use the
-      # unwrapped linker as workaround. See:
-      #
-      # https://github.com/NixOS/nixpkgs/issues/321667
-      "LD=${stdenv.cc.bintools.bintools}/bin/${stdenv.cc.targetPrefix}ld"
-    ]
-    ++ (stdenv.hostPlatform.linux-kernel.makeFlags or [ ])
-    ++ extraMakeFlags;
+    commonMakeFlags = import ./common-flags.nix {
+      inherit
+        lib
+        stdenv
+        buildPackages
+        extraMakeFlags
+        ;
+    };
   in
 
   stdenv.mkDerivation (

pkgs/os-specific/linux/minimal-bootstrap/gcc/4.6.cxx.nix

···
       license = licenses.gpl3Plus;
       teams = [ teams.minimal-bootstrap ];
       platforms = platforms.unix;
+      mainProgram = "gcc";
     };
   }
   ''

pkgs/os-specific/linux/minimal-bootstrap/gcc/4.6.nix

···
       license = licenses.gpl3Plus;
       teams = [ teams.minimal-bootstrap ];
       platforms = platforms.unix;
+      mainProgram = "gcc";
     };
   }
   ''

pkgs/os-specific/linux/minimal-bootstrap/gcc/8.nix

···
       license = licenses.gpl3Plus;
       teams = [ teams.minimal-bootstrap ];
       platforms = platforms.unix;
+      mainProgram = "gcc";
     };
   }
   ''

pkgs/os-specific/linux/minimal-bootstrap/gcc/latest.nix

···
       license = licenses.gpl3Plus;
       teams = [ teams.minimal-bootstrap ];
       platforms = platforms.unix;
+      mainProgram = "gcc";
     };
   }
   ''