nixpkgs/pkgs/stdenv/darwin/default.nix

# This file contains the standard build environment for Darwin. It is based on LLVM and is patterned
# after the Linux stdenv. It shares similar goals to the Linux standard environment in that the
# resulting environment should be built purely and not contain any references to it.
#
# For more on the design of the stdenv and updating it, see `README.md`.
#
# See also the top comments of the Linux stdenv `../linux/default.nix` for a good overview of
# the bootstrap process and working with it.

{
  lib,
  localSystem,
  crossSystem,
  config,
  overlays,
  crossOverlays ? [ ],
  # Allow passing in bootstrap files directly so we can test the stdenv bootstrap process when changing the bootstrap tools
  bootstrapFiles ? (config.replaceBootstrapFiles or lib.id) (
    if localSystem.isAarch64 then
      import ./bootstrap-files/aarch64-apple-darwin.nix
    else
      import ./bootstrap-files/x86_64-apple-darwin.nix
  ),
}:

assert crossSystem == localSystem;

let
  inherit (localSystem) system;

  useAppleSDKLibs = lib.versionAtLeast localSystem.darwinSdkVersion "11";

  commonImpureHostDeps = [
    "/bin/sh"
    "/usr/lib/libSystem.B.dylib"
    "/usr/lib/system/libunc.dylib" # This dependency is "hidden", so our scanning code doesn't pick it up
  ];

  isFromNixpkgs = pkg: !(isFromBootstrapFiles pkg);
  isFromBootstrapFiles = pkg: pkg.passthru.isFromBootstrapFiles or false;
  isBuiltByNixpkgsCompiler = pkg: isFromNixpkgs pkg && isFromNixpkgs pkg.stdenv.cc.cc;
  isBuiltByBootstrapFilesCompiler = pkg: isFromNixpkgs pkg && isFromBootstrapFiles pkg.stdenv.cc.cc;

  commonPreHook = ''
    export NIX_ENFORCE_NO_NATIVE=''${NIX_ENFORCE_NO_NATIVE-1}
    export NIX_ENFORCE_PURITY=''${NIX_ENFORCE_PURITY-1}
    export NIX_IGNORE_LD_THROUGH_GCC=1
    unset SDKROOT
  '';

  bootstrapTools =
    derivation (
      {
        inherit system;

        name = "bootstrap-tools";
        builder = "${bootstrapFiles.unpack}/bin/bash";

        args = [
          "${bootstrapFiles.unpack}/bootstrap-tools-unpack.sh"
          bootstrapFiles.bootstrapTools
        ];

        PATH = lib.makeBinPath [
          (placeholder "out")
          bootstrapFiles.unpack
        ];

        __impureHostDeps = commonImpureHostDeps;
      }
      // lib.optionalAttrs config.contentAddressedByDefault {
        __contentAddressed = true;
        outputHashAlgo = "sha256";
        outputHashMode = "recursive";
      }
    )
    // {
      passthru.isFromBootstrapFiles = true;
    };

  stageFun =
    prevStage:
    {
      name,
      overrides ? (self: super: { }),
      extraNativeBuildInputs ? [ ],
      extraPreHook ? "",
    }:

    let
      cc =
        if prevStage.llvmPackages.clang-unwrapped == null then
          null
        else
          lib.makeOverridable (import ../../build-support/cc-wrapper) {
            name = "${name}-clang-wrapper";

            nativeTools = false;
            nativeLibc = false;

            expand-response-params = lib.optionalString (
              prevStage.stdenv.hasCC or false && prevStage.stdenv.cc != "/dev/null"
            ) prevStage.expand-response-params;

            extraPackages = [ prevStage.llvmPackages.compiler-rt ];

            extraBuildCommands =
              let
                inherit (prevStage.llvmPackages) clang-unwrapped compiler-rt release_version;
              in
              ''
                function clangResourceRootIncludePath() {
                  clangLib="$1/lib/clang"
                  if (( $(ls "$clangLib" | wc -l) > 1 )); then
                    echo "Multiple LLVM versions were found at "$clangLib", but there must only be one used when building the stdenv." >&2
                    exit 1
                  fi
                  echo "$clangLib/$(ls -1 "$clangLib")/include"
                }

                rsrc="$out/resource-root"
                mkdir "$rsrc"
                ln -s "$(clangResourceRootIncludePath "${clang-unwrapped.lib}")" "$rsrc"
                ln -s "${compiler-rt.out}/lib"   "$rsrc/lib"
                ln -s "${compiler-rt.out}/share" "$rsrc/share"
                echo "-resource-dir=$rsrc" >> $out/nix-support/cc-cflags
              '';

            cc = prevStage.llvmPackages.clang-unwrapped;
            bintools = prevStage.darwin.binutils;

            isClang = true;
            libc = prevStage.darwin.Libsystem;
            inherit (prevStage.llvmPackages) libcxx;

            inherit lib;
            inherit (prevStage) coreutils gnugrep;

            stdenvNoCC = prevStage.ccWrapperStdenv;
            runtimeShell = prevStage.ccWrapperStdenv.shell;
          };

      bash = prevStage.bash or bootstrapTools;

      thisStdenv = import ../generic {
        name = "${name}-stdenv-darwin";

        buildPlatform = localSystem;
        hostPlatform = localSystem;
        targetPlatform = localSystem;

        inherit config;

        extraBuildInputs = [ prevStage.darwin.CF ];
        extraNativeBuildInputs = extraNativeBuildInputs ++ [ prevStage.darwin.apple_sdk.sdkRoot ];

        preHook =
          lib.optionalString (!isBuiltByNixpkgsCompiler bash) ''
            # Don't patch #!/interpreter because it leads to retained
            # dependencies on the bootstrapTools in the final stdenv.
            dontPatchShebangs=1
          ''
          + ''
            ${commonPreHook}
            ${extraPreHook}
          ''
          + lib.optionalString (prevStage.darwin ? locale) ''
            export PATH_LOCALE=${prevStage.darwin.locale}/share/locale
          '';

        shell = bash + "/bin/bash";
        initialPath = [
          bash
          bootstrapTools
        ];

        fetchurlBoot = import ../../build-support/fetchurl {
          inherit lib;
          stdenvNoCC = prevStage.ccWrapperStdenv or thisStdenv;
          curl = bootstrapTools;
        };

        inherit cc;

        # The stdenvs themselves don't use mkDerivation, so I need to specify this here
        __stdenvImpureHostDeps = commonImpureHostDeps;
        __extraImpureHostDeps = commonImpureHostDeps;

        # Using the bootstrap tools curl for fetchers allows the stdenv bootstrap to avoid
        # having a dependency on curl, allowing curl to be updated without triggering a
        # new stdenv bootstrap on Darwin.
        overrides =
          self: super:
          (overrides self super)
          // {
            fetchurl = thisStdenv.fetchurlBoot;
            fetchpatch = super.fetchpatch.override { inherit (self) fetchurl; };
            fetchzip = super.fetchzip.override { inherit (self) fetchurl; };
          };
      };

    in
    {
      inherit config overlays;
      stdenv = thisStdenv;
    };
in
assert bootstrapTools.passthru.isFromBootstrapFiles or false; # sanity check
[
  (
    { }:
    {
      __raw = true;

      cctools = true;
      ld64 = true;

      coreutils = null;
      gnugrep = null;

      pbzx = null;
      cpio = null;

      darwin = {
        apple_sdk.sdkRoot = null;
        binutils = null;
        binutils-unwrapped = null;
        print-reexports = null;
        rewrite-tbd = null;
        sigtool = null;
        CF = null;
        Libsystem = null;
      };

      llvmPackages = {
        clang-unwrapped = null;
        libllvm = null;
        libcxx = null;
        compiler-rt = null;
      };
    }
  )

  # Create a stage with the bootstrap tools. This will be used to build the subsequent stages and
  # build up the standard environment.
  #
  # Note: Each stage depends only on the the packages in `prevStage`. If a package is not to be
  # rebuilt, it should be passed through by inheriting it.
  (
    prevStage:
    stageFun prevStage {
      name = "bootstrap-stage0";

      overrides = self: super: {
        # We thread stage0's stdenv through under this name so downstream stages
        # can use it for wrapping gcc too. This way, downstream stages don't need
        # to refer to this stage directly, which violates the principle that each
        # stage should only access the stage that came before it.
        ccWrapperStdenv = self.stdenv;

        bash = bootstrapTools // {
          shellPath = "/bin/bash";
        };

        coreutils = bootstrapTools;
        cpio = bootstrapTools;
        gnugrep = bootstrapTools;
        pbzx = bootstrapTools;

        cctools = super.stdenv.mkDerivation {
          pname = "bootstrap-stage0-cctools";
          version = "boot";

          buildCommand = ''
            declare -a cctools=(
              ar
              bitcode_strip
              check_dylib
              checksyms
              cmpdylib
              codesign_allocate
              ctf_insert
              depinfo
              diagtest
              gas
              gprof
              install_name_tool
              libtool
              lipo
              mtoc
              mtor
              nm
              nmedit
              otool
              pagestuff
              ranlib
              redo_prebinding
              seg_addr_table
              seg_hack
              segedit
              size
              strings
              strip
              vtool
            )

            mkdir -p "$out/bin"
            for tool in "''${cctools[@]}"; do
              toolsrc="${bootstrapTools}/bin/$tool"
              if [ -e "$toolsrc" ]; then
                ln -s "$toolsrc" "$out/bin"
              fi
            done

            # Copy only the required headers to avoid accidentally linking headers that belong to other packages,
            # which can cause problems when building Libsystem in the source-based SDK.
            declare -a machohdrs=(
              arch.h
              fat.h
              fixup-chains.h
              getsect.h
              ldsyms.h
              loader.h
              nlist.h
              ranlib.h
              reloc.h
              stab.h
              swap.h
              arm
              arm64
              hppa
              i386
              i860
              m68k
              m88k
              ppc
              sparc
              x86_64
            )

            mkdir -p "$out/include/mach-o"
            for header in "''${machohdrs[@]}"; do
              machosrc="${bootstrapTools}/include-Libsystem/mach-o/$header"
              if [ -e "$machosrc" ]; then
                cp -r "$machosrc" "$out/include/mach-o/$header"
              fi
            done
          '';

          passthru = {
            isFromBootstrapFiles = true;
            targetPrefix = "";
          };
        };

        ld64 = bootstrapTools // {
          targetPrefix = "";
          version = "boot";
        };

        darwin = super.darwin.overrideScope (
          selfDarwin: superDarwin:
          {
            # Prevent CF from being propagated to the initial stdenv. Packages that require it
            # will have to manually add it to their build inputs.
            CF = null;

            binutils = super.wrapBintoolsWith {
              name = "bootstrap-stage0-binutils-wrapper";

              nativeTools = false;
              nativeLibc = false;

              expand-response-params = "";
              libc = selfDarwin.Libsystem;

              inherit lib;
              inherit (self) stdenvNoCC coreutils gnugrep;
              runtimeShell = self.stdenvNoCC.shell;

              bintools = selfDarwin.binutils-unwrapped;

              # Bootstrap tools cctools needs the hook and wrappers to make sure things are signed properly.
              # This can be dropped once the bootstrap tools cctools has been updated to 1010.6.
              extraBuildCommands = ''
                echo 'source ${selfDarwin.postLinkSignHook}' >> $out/nix-support/post-link-hook

                export signingUtils=${selfDarwin.signingUtils}

                wrap \
                  install_name_tool ${../../build-support/bintools-wrapper/darwin-install_name_tool-wrapper.sh} \
                  "${selfDarwin.binutils-unwrapped}/bin/install_name_tool"

                wrap \
                  strip ${../../build-support/bintools-wrapper/darwin-strip-wrapper.sh} \
                  "${selfDarwin.binutils-unwrapped}/bin/strip"
              '';
            };

            binutils-unwrapped =
              (superDarwin.binutils-unwrapped.overrideAttrs (old: {
                version = "boot";
                passthru = (old.passthru or { }) // {
                  isFromBootstrapFiles = true;
                };
              })).override
                { enableManpages = false; };

            locale = self.stdenv.mkDerivation {
              name = "bootstrap-stage0-locale";
              buildCommand = ''
                mkdir -p $out/share/locale
              '';
            };

            print-reexports = bootstrapTools;

            rewrite-tbd = bootstrapTools;

            sigtool = bootstrapTools;
          }
          // lib.optionalAttrs (!useAppleSDKLibs) {
            Libsystem = self.stdenv.mkDerivation {
              name = "bootstrap-stage0-Libsystem";
              buildCommand = ''
                mkdir -p $out

                cp -r ${selfDarwin.darwin-stubs}/usr/lib $out/lib
                chmod -R +w $out/lib
                substituteInPlace $out/lib/libSystem.B.tbd --replace /usr/lib/system $out/lib/system

                ln -s libSystem.B.tbd $out/lib/libSystem.tbd

                for name in c dbm dl info m mx poll proc pthread rpcsvc util gcc_s.10.4 gcc_s.10.5; do
                  ln -s libSystem.tbd $out/lib/lib$name.tbd
                done

                ln -s ${bootstrapTools}/lib/*.o $out/lib

                ln -s ${bootstrapTools}/lib/libresolv.9.dylib $out/lib
                ln -s libresolv.9.dylib $out/lib/libresolv.dylib

                ln -s ${bootstrapTools}/include-Libsystem $out/include
              '';
              passthru.isFromBootstrapFiles = true;
            };
          }
        );

        llvmPackages =
          super.llvmPackages
          // (
            let
              tools = super.llvmPackages.tools.extend (
                selfTools: _: {
                  libclang = self.stdenv.mkDerivation {
                    name = "bootstrap-stage0-clang";
                    version = "boot";
                    outputs = [
                      "out"
                      "lib"
                    ];
                    buildCommand = ''
                      mkdir -p $out/lib
                      ln -s $out $lib
                      ln -s ${bootstrapTools}/bin       $out/bin
                      ln -s ${bootstrapTools}/lib/clang $out/lib
                      ln -s ${bootstrapTools}/include   $out
                    '';
                    passthru = {
                      isFromBootstrapFiles = true;
                      hardeningUnsupportedFlags = [
                        "fortify3"
                        "shadowstack"
                        "stackclashprotection"
                        "zerocallusedregs"
                      ];
                    };
                  };
                  libllvm = self.stdenv.mkDerivation {
                    name = "bootstrap-stage0-llvm";
                    outputs = [
                      "out"
                      "lib"
                    ];
                    buildCommand = ''
                      mkdir -p $out/bin $out/lib
                      ln -s $out $lib
                      for tool in ${toString super.darwin.binutils-unwrapped.llvm_cmds}; do
                        cctoolsTool=''${tool//-/_}
                        toolsrc="${bootstrapTools}/bin/$cctoolsTool"
                        if [ -e "$toolsrc" ]; then
                          ln -s "$toolsrc" $out/bin/llvm-$tool
                        fi
                      done
                      ln -s ${bootstrapTools}/bin/dsymutil $out/bin/dsymutil
                      ln -s ${bootstrapTools}/lib/libLLVM* $out/lib
                    '';
                    passthru.isFromBootstrapFiles = true;
                  };
                }
              );
              libraries = super.llvmPackages.libraries.extend (
                _: _: {
                  libcxx = self.stdenv.mkDerivation {
                    name = "bootstrap-stage0-libcxx";
                    buildCommand = ''
                      mkdir -p $out/lib $out/include
                      ln -s ${bootstrapTools}/lib/libc++.dylib $out/lib
                      ln -s ${bootstrapTools}/include/c++      $out/include
                    '';
                    passthru = {
                      isLLVM = true;
                      isFromBootstrapFiles = true;
                    };
                  };
                  compiler-rt = self.stdenv.mkDerivation {
                    name = "bootstrap-stage0-compiler-rt";
                    buildCommand = ''
                      mkdir -p $out/lib $out/share
                      ln -s ${bootstrapTools}/lib/libclang_rt* $out/lib
                      ln -s ${bootstrapTools}/lib/darwin       $out/lib
                    '';
                    passthru.isFromBootstrapFiles = true;
                  };
                }
              );
            in
            { inherit tools libraries; } // tools // libraries
          );
      };

      extraPreHook = ''
        stripDebugFlags="-S" # llvm-strip does not support "-p" for Mach-O
      '';
    }
  )

  # This stage is primarily responsible for setting up versions of certain dependencies needed
  # by the rest of the build process. This stage also builds CF and Libsystem to simplify assertions
  # and assumptions for later by making sure both packages are present on x86_64-darwin and aarch64-darwin.
  (
    prevStage:
    # previous stage0 stdenv:
    assert lib.all isFromBootstrapFiles (
      with prevStage;
      [
        bash
        cctools
        coreutils
        cpio
        gnugrep
        ld64
      ]
      ++ lib.optionals useAppleSDKLibs [ pbzx ]
    );

    assert lib.all isFromBootstrapFiles (
      with prevStage.darwin;
      [
        binutils-unwrapped
        print-reexports
        rewrite-tbd
        sigtool
      ]
    );

    assert (!useAppleSDKLibs) -> lib.all isFromBootstrapFiles (with prevStage.darwin; [ Libsystem ]);
    assert useAppleSDKLibs -> lib.all isFromNixpkgs (with prevStage.darwin; [ Libsystem ]);
    assert lib.all isFromNixpkgs (
      with prevStage.darwin;
      [
        dyld
        launchd
        xnu
      ]
    );
    assert (with prevStage.darwin; (!useAppleSDKLibs) -> CF == null);

    assert lib.all isFromBootstrapFiles (
      with prevStage.llvmPackages;
      [
        clang-unwrapped
        libclang
        libllvm
        llvm
        compiler-rt
        libcxx
      ]
    );

    stageFun prevStage {
      name = "bootstrap-stage1";

      overrides = self: super: {
        inherit (prevStage)
          ccWrapperStdenv
          cctools
          coreutils
          gnugrep
          ld64
          ;

        binutils-unwrapped = builtins.throw "nothing in the Darwin bootstrap should depend on GNU binutils";
        curl = builtins.throw "nothing in the Darwin bootstrap can depend on curl";

        # Use this stage’s CF to build CMake. It’s required but can’t be included in the stdenv.
        cmake = self.cmakeMinimal;
        cmakeMinimal = super.cmakeMinimal.overrideAttrs (old: {
          buildInputs = old.buildInputs ++ [ self.darwin.CF ];
        });

        # Disable tests because they use dejagnu, which fails to run.
        libffi = super.libffi.override { doCheck = false; };

        # Use libconvReal to break an infinite recursion. It will be dropped in the next stage.
        libiconv = super.libiconvReal;

        # Avoid pulling in a full python and its extra dependencies for the llvm/clang builds.
        libxml2 = super.libxml2.override { pythonSupport = false; };

        ninja = super.ninja.override { buildDocs = false; };

        # Use this stage’s CF to build Python. It’s required, but it can’t be included in the stdenv.
        python3 = self.python3Minimal;
        python3Minimal =
          (super.python3Minimal.override { self = self.python3Minimal; }).overrideAttrs
            (old: {
              buildInputs = old.buildInputs or [ ] ++ [ self.darwin.CF ];
            });

        scons = super.scons.override { python3Packages = self.python3Minimal.pkgs; };

        darwin = super.darwin.overrideScope (
          selfDarwin: superDarwin: {
            apple_sdk = superDarwin.apple_sdk // {
              inherit (prevStage.darwin.apple_sdk) sdkRoot;
            };

            # Use this stage’s CF to build configd. It’s required, but it can’t be included in the stdenv.
            configd = superDarwin.configd.overrideAttrs (old: {
              buildInputs = old.buildInputs or [ ] ++ [ self.darwin.CF ];
            });

            signingUtils = prevStage.darwin.signingUtils.override { inherit (selfDarwin) sigtool; };

            postLinkSignHook = prevStage.darwin.postLinkSignHook.override { inherit (selfDarwin) sigtool; };

            # Rewrap binutils with the real Libsystem
            binutils = superDarwin.binutils.override {
              inherit (self) coreutils;
              bintools = selfDarwin.binutils-unwrapped;
              libc = selfDarwin.Libsystem;
              # TODO(@sternenseemann): can this be removed?
              runtimeShell = "${bootstrapTools}/bin/bash";

              # Bootstrap tools cctools needs the hook to make sure things are signed properly.
              # This can be dropped once the bootstrap tools cctools has been updated to 1010.6.
              extraBuildCommands = ''
                echo 'source ${selfDarwin.postLinkSignHook}' >> $out/nix-support/post-link-hook

                export signingUtils=${selfDarwin.signingUtils}

                wrap \
                  install_name_tool ${../../build-support/bintools-wrapper/darwin-install_name_tool-wrapper.sh} \
                  "${selfDarwin.binutils-unwrapped}/bin/install_name_tool"

                wrap \
                  strip ${../../build-support/bintools-wrapper/darwin-strip-wrapper.sh} \
                  "${selfDarwin.binutils-unwrapped}/bin/strip"
              '';
            };

            # Avoid building unnecessary Python dependencies due to building LLVM manpages.
            binutils-unwrapped = superDarwin.binutils-unwrapped.override {
              inherit (self) cctools ld64;
              enableManpages = false;
            };
          }
        );

        llvmPackages =
          super.llvmPackages
          // (
            let
              tools = super.llvmPackages.tools.extend (
                _: _: {
                  inherit (prevStage.llvmPackages)
                    clang-unwrapped
                    libclang
                    libllvm
                    llvm
                    ;
                }
              );
              libraries = super.llvmPackages.libraries.extend (
                _: _: { inherit (prevStage.llvmPackages) compiler-rt libcxx; }
              );
            in
            {
              inherit tools libraries;
              inherit (prevStage.llvmPackages) release_version;
            }
            // tools
            // libraries
          );
      };

      extraNativeBuildInputs = lib.optionals localSystem.isAarch64 [
        prevStage.updateAutotoolsGnuConfigScriptsHook
        prevStage.gnu-config
      ];

      extraPreHook = ''
        stripDebugFlags="-S" # llvm-strip does not support "-p" for Mach-O
      '';
    }
  )

  # Build sysctl for use by LLVM’s check phase. It must be built separately to avoid an infinite recursion.
  (
    prevStage:
    # previous stage1 stdenv:
    assert lib.all isFromBootstrapFiles (
      with prevStage;
      [
        cctools
        coreutils
        gnugrep
        ld64
      ]
    );

    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage;
      [
        autoconf
        automake
        bash
        bison
        brotli
        cmake
        cpio
        cyrus_sasl
        db
        ed
        expat
        flex
        gettext
        gmp
        groff
        icu
        libedit
        libffi
        libiconv
        libidn2
        libkrb5
        libssh2
        libtool
        libunistring
        libxml2
        m4
        ncurses
        nghttp2
        ninja
        openldap
        openssh
        openssl
        patchutils
        pbzx
        perl
        pkg-config.pkg-config
        python3
        python3Minimal
        scons
        serf
        sqlite
        subversion
        texinfo
        unzip
        which
        xz
        zlib
        zstd
      ]
    );

    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage.darwin;
      [
        locale
        print-reexports
        rewrite-tbd
        sigtool
      ]
    );

    assert
      (!useAppleSDKLibs)
      -> lib.all isBuiltByBootstrapFilesCompiler (
        with prevStage.darwin;
        [
          Libsystem
          configd
        ]
      );
    assert (!useAppleSDKLibs) -> lib.all isFromNixpkgs (with prevStage.darwin; [ CF ]);
    assert
      useAppleSDKLibs
      -> lib.all isFromNixpkgs (
        with prevStage.darwin;
        [
          CF
          Libsystem
          libobjc
        ]
      );
    assert lib.all isFromNixpkgs (
      with prevStage.darwin;
      [
        binutils-unwrapped
        dyld
        launchd
        xnu
      ]
    );

    assert lib.all isFromBootstrapFiles (
      with prevStage.llvmPackages;
      [
        clang-unwrapped
        libclang
        libllvm
        llvm
        compiler-rt
        libcxx
      ]
    );

    assert lib.getVersion prevStage.stdenv.cc.bintools.bintools == "boot";

    stageFun prevStage {
      name = "bootstrap-stage1-sysctl";

      overrides = self: super: {
        inherit (prevStage)
          ccWrapperStdenv
          autoconf
          automake
          bash
          binutils-unwrapped
          bison
          brotli
          cctools
          cmake
          cmakeMinimal
          coreutils
          cpio
          curl
          cyrus_sasl
          db
          ed
          expat
          flex
          gettext
          gmp
          gnugrep
          groff
          icu
          ld64
          libedit
          libffi
          libidn2
          libkrb5
          libssh2
          libtool
          libunistring
          libxml2
          m4
          ncurses
          nghttp2
          ninja
          openldap
          openssh
          openssl
          patchutils
          pbzx
          perl
          pkg-config
          python3Minimal
          scons
          sed
          serf
          sharutils
          sqlite
          subversion
          texinfo
          unzip
          which
          xz
          zlib
          zstd
          ;

        # Avoid pulling in openldap just to run Meson’s tests.
        meson = super.meson.overrideAttrs { doInstallCheck = false; };

        # The bootstrap Python needs its own `pythonAttr` to make sure the override works properly.
        python3 = self.python3-bootstrap;
        python3-bootstrap = super.python3.override {
          self = self.python3-bootstrap;
          pythonAttr = "python3-bootstrap";
          enableLTO = false;
        };

        darwin = super.darwin.overrideScope (
          _: superDarwin: {
            inherit (prevStage.darwin)
              CF
              sdkRoot
              Libsystem
              binutils
              binutils-unwrapped
              configd
              darwin-stubs
              dtrace
              dyld
              launchd
              libclosure
              libdispatch
              libobjc
              locale
              objc4
              postLinkSignHook
              print-reexports
              rewrite-tbd
              signingUtils
              sigtool
              ;

            apple_sdk = superDarwin.apple_sdk // {
              inherit (prevStage.darwin.apple_sdk) sdkRoot;
            };
          }
        );

        llvmPackages =
          super.llvmPackages
          // (
            let
              tools = super.llvmPackages.tools.extend (
                _: _: {
                  inherit (prevStage.llvmPackages)
                    clang-unwrapped
                    libclang
                    libllvm
                    llvm
                    ;
                  clang = prevStage.stdenv.cc;
                }
              );
              libraries = super.llvmPackages.libraries.extend (
                _: _: { inherit (prevStage.llvmPackages) compiler-rt libcxx; }
              );
            in
            {
              inherit tools libraries;
              inherit (prevStage.llvmPackages) release_version;
            }
            // tools
            // libraries
          );
      };

      extraNativeBuildInputs = lib.optionals localSystem.isAarch64 [
        prevStage.updateAutotoolsGnuConfigScriptsHook
        prevStage.gnu-config
      ];

      extraPreHook = ''
        stripDebugFlags="-S" # llvm-strip does not support "-p" for Mach-O
      '';
    }
  )

  # First rebuild of LLVM. While this LLVM is linked to a bunch of junk from the bootstrap tools,
  # the libc++ and libc++abi it produces are not. The compiler will be rebuilt in a later stage,
  # but those libraries will be used in the final stdenv.
  #
  # Rebuild coreutils and gnugrep to avoid unwanted references to the bootstrap tools on `PATH`.
  #
  # The first build of cctools is deferred until this stage because it depends on LLVM headers
  # that are not included in the bootstrap tools tarball.
  (
    prevStage:
    # previous stage-sysctl stdenv:
    assert lib.all isFromBootstrapFiles (
      with prevStage;
      [
        cctools
        coreutils
        gnugrep
        ld64
      ]
    );

    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage;
      [
        atf
        autoconf
        automake
        bash
        bison
        brotli
        cmake
        cpio
        cyrus_sasl
        db
        ed
        expat
        flex
        gettext
        gmp
        groff
        icu
        kyua
        libedit
        libffi
        libiconv
        libidn2
        libkrb5
        libssh2
        libtapi
        libtool
        libunistring
        libxml2
        m4
        meson
        ncurses
        nghttp2
        ninja
        openldap
        openssh
        openssl
        patchutils
        pbzx
        perl
        pkg-config.pkg-config
        python3
        python3Minimal
        scons
        serf
        sqlite
        subversion
        sysctl.provider
        texinfo
        unzip
        which
        xz
        zlib
        zstd
      ]
    );

    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage.darwin;
      [
        locale
        print-reexports
        rewrite-tbd
        sigtool
      ]
    );

    assert
      (!useAppleSDKLibs)
      -> lib.all isBuiltByBootstrapFilesCompiler (
        with prevStage.darwin;
        [
          Libsystem
          configd
        ]
      );
    assert (!useAppleSDKLibs) -> lib.all isFromNixpkgs (with prevStage.darwin; [ CF ]);
    assert
      useAppleSDKLibs
      -> lib.all isFromNixpkgs (
        with prevStage.darwin;
        [
          CF
          Libsystem
          libobjc
        ]
      );
    assert lib.all isFromNixpkgs (
      with prevStage.darwin;
      [
        binutils-unwrapped
        dyld
        launchd
        xnu
      ]
    );

    assert lib.all isFromBootstrapFiles (
      with prevStage.llvmPackages;
      [
        clang-unwrapped
        libclang
        libllvm
        llvm
        compiler-rt
        libcxx
      ]
    );

    stageFun prevStage {
      name = "bootstrap-stage-xclang";

      overrides = self: super: {
        inherit (prevStage)
          ccWrapperStdenv
          atf
          autoconf
          automake
          bash
          binutils-unwrapped
          bison
          brotli
          cmake
          cmakeMinimal
          cpio
          curl
          cyrus_sasl
          db
          ed
          expat
          flex
          gettext
          gmp
          groff
          icu
          kyua
          libedit
          libffi
          libiconv
          libidn2
          libkrb5
          libssh2
          libtool
          libunistring
          libxml2
          m4
          meson
          ncurses
          nghttp2
          ninja
          openldap
          openssh
          openssl
          patchutils
          pbzx
          perl
          pkg-config
          python3
          python3Minimal
          scons
          sed
          serf
          sharutils
          sqlite
          subversion
          sysctl
          texinfo
          unzip
          which
          xz
          zlib
          zstd
          ;

        # Disable ld64’s install check phase because the required LTO libraries are not built yet.
        ld64 = super.ld64.overrideAttrs { doInstallCheck = false; };

        darwin = super.darwin.overrideScope (
          selfDarwin: superDarwin: {
            inherit (prevStage.darwin)
              CF
              Libsystem
              configd
              darwin-stubs
              dyld
              launchd
              libclosure
              libdispatch
              libobjc
              locale
              objc4
              postLinkSignHook
              print-reexports
              rewrite-tbd
              signingUtils
              sigtool
              ;

            apple_sdk = superDarwin.apple_sdk // {
              inherit (prevStage.darwin.apple_sdk) sdkRoot;
            };

            binutils = superDarwin.binutils.override {
              inherit (prevStage) expand-response-params;
              libc = selfDarwin.Libsystem;
            };

            # Avoid building unnecessary Python dependencies due to building LLVM manpages.
            binutils-unwrapped = superDarwin.binutils-unwrapped.override { enableManpages = false; };
          }
        );

        llvmPackages =
          super.llvmPackages
          // (
            let
              llvmMajor = lib.versions.major super.llvmPackages.release_version;

              # libc++, and libc++abi do not need CoreFoundation. Avoid propagating the CF from prior
              # stages to the final stdenv via rpath by dropping it from `extraBuildInputs`.
              stdenvNoCF = self.stdenv.override { extraBuildInputs = [ ]; };

              libcxxBootstrapStdenv = self.overrideCC stdenvNoCF (
                self.llvmPackages.clangNoCompilerRtWithLibc.override {
                  nixSupport.cc-cflags = [ "-nostdlib" ];
                  nixSupport.cc-ldflags = [ "-lSystem" ];
                }
              );

              tools = super.llvmPackages.tools.extend (
                selfTools: superTools: {
                  # LLVM’s check phase takes a while to run, so disable it in the first LLVM build to speed up the bootstrap.
                  libllvm = superTools.libllvm.override { doCheck = false; };
                }
              );

              libraries = super.llvmPackages.libraries.extend (
                selfLib: superLib: {
                  compiler-rt = null;
                  libcxx = superLib.libcxx.override ({ stdenv = libcxxBootstrapStdenv; });
                }
              );
            in
            { inherit tools libraries; } // tools // libraries
          );
      };

      extraNativeBuildInputs = lib.optionals localSystem.isAarch64 [
        prevStage.updateAutotoolsGnuConfigScriptsHook
        prevStage.gnu-config
      ];

      extraPreHook = ''
        stripDebugFlags="-S" # llvm-strip does not support "-p" for Mach-O
      '';
    }
  )

  # This stage rebuilds Libsystem. It also rebuilds bash, which will be needed in later stages
  # to use in patched shebangs (e.g., to make sure `icu-config` uses bash from nixpkgs).
  (
    prevStage:
    # previous stage-xclang stdenv:
    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage;
      [
        atf
        autoconf
        automake
        bash
        bison
        cctools
        cmake
        cmakeMinimal
        coreutils
        cpio
        cyrus_sasl
        db
        ed
        expat
        flex
        gettext
        gmp
        gnugrep
        groff
        icu
        kyua
        ld64
        libedit
        libtapi
        libtool
        m4
        meson
        ninja
        openbsm
        openldap
        openpam
        openssh
        patchutils
        pbzx
        perl
        pkg-config.pkg-config
        python3
        python3Minimal
        scons
        serf
        sqlite
        subversion
        sysctl.provider
        texinfo
        unzip
        which
        xz
      ]
    );

    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage;
      [
        brotli
        libffi
        libiconv
        libidn2
        libkrb5
        libssh2
        libunistring
        libxml2
        ncurses
        nghttp2
        openssl
        zlib
        zstd
      ]
    );

    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage.darwin;
      [
        locale
        print-reexports
        rewrite-tbd
        sigtool
      ]
    );

    assert
      (!useAppleSDKLibs)
      -> lib.all isBuiltByBootstrapFilesCompiler (
        with prevStage.darwin;
        [
          Libsystem
          configd
        ]
      );
    assert (!useAppleSDKLibs) -> lib.all isFromNixpkgs (with prevStage.darwin; [ CF ]);
    assert
      useAppleSDKLibs
      -> lib.all isFromNixpkgs (
        with prevStage.darwin;
        [
          CF
          Libsystem
          libobjc
        ]
      );
    assert lib.all isFromNixpkgs (
      with prevStage.darwin;
      [
        binutils-unwrapped
        dyld
        launchd
        libclosure
        libdispatch
        xnu
      ]
    );

    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage.llvmPackages;
      [
        clang-unwrapped
        libclang
        libllvm
        llvm
      ]
    );
    assert lib.all isBuiltByNixpkgsCompiler (with prevStage.llvmPackages; [ libcxx ]);
    assert prevStage.llvmPackages.compiler-rt == null;

    stageFun prevStage {

      name = "bootstrap-stage2";

      overrides = self: super: {
        inherit (prevStage)
          ccWrapperStdenv
          atf
          autoconf
          automake
          binutils-unwrapped
          bison
          brotli
          cctools
          cmake
          cmakeMinimal
          coreutils
          cpio
          curl
          cyrus_sasl
          db
          ed
          expat
          flex
          gettext
          gmp
          gnugrep
          groff
          icu
          kyua
          ld64
          libedit
          libffi
          libiconv
          libidn2
          libkrb5
          libssh2
          libtapi
          libtool
          libunistring
          libxml2
          m4
          meson
          ncurses
          nghttp2
          ninja
          openbsm
          openldap
          openpam
          openssh
          openssl
          patchutils
          pbzx
          perl
          pkg-config
          python3
          python3Minimal
          scons
          serf
          sqlite
          subversion
          sysctl
          texinfo
          unzip
          which
          xz
          zlib
          zstd
          ;

        # Bash must be linked against the system CoreFoundation instead of the open-source one.
        # Otherwise, there will be a dependency cycle: bash -> CF -> icu -> bash (for icu^dev).
        bash = super.bash.overrideAttrs (super: {
          buildInputs = super.buildInputs ++ [ self.darwin.apple_sdk.frameworks.CoreFoundation ];
        });

        darwin = super.darwin.overrideScope (
          selfDarwin: superDarwin: {
            inherit (prevStage.darwin)
              binutils-unwrapped
              configd
              darwin-stubs
              launchd
              locale
              postLinkSignHook
              print-reexports
              rewrite-tbd
              signingUtils
              sigtool
              ;

            apple_sdk = superDarwin.apple_sdk // {
              inherit (prevStage.darwin.apple_sdk) sdkRoot;
            };

            # Rewrap binutils so it uses the rebuilt Libsystem.
            binutils =
              superDarwin.binutils.override {
                inherit (prevStage) expand-response-params;
                libc = selfDarwin.Libsystem;
              }
              // {
                passthru = {
                  inherit (prevStage.bintools.passthru) isFromBootstrapFiles;
                };
              };
          }
        );

        llvmPackages =
          super.llvmPackages
          // (
            let
              tools = super.llvmPackages.tools.extend (
                _: _: {
                  inherit (prevStage.llvmPackages)
                    clang-unwrapped
                    clangNoCompilerRtWithLibc
                    libclang
                    lld
                    libllvm
                    llvm
                    ;
                }
              );

              libraries = super.llvmPackages.libraries.extend (
                selfLib: superLib: {
                  inherit (prevStage.llvmPackages) libcxx;

                  # Make sure compiler-rt is linked against the CF from this stage, which can be
                  # propagated to the final stdenv. CF is required by ASAN.
                  compiler-rt = superLib.compiler-rt.override ({
                    inherit (self.llvmPackages) libllvm;
                    stdenv = self.stdenv.override { extraBuildInputs = [ self.darwin.CF ]; };
                  });
                }
              );
            in
            {
              inherit tools libraries;
              inherit (prevStage.llvmPackages) release_version;
            }
            // tools
            // libraries
          );

        # Don’t link anything in this stage against CF to prevent propagating CF from prior stages to
        # the final stdenv, which happens because of the rpath hook.
        stdenv =
          let
            stdenvNoCF = super.stdenv.override { extraBuildInputs = [ ]; };
          in
          self.overrideCC stdenvNoCF (
            self.llvmPackages.clangNoCompilerRtWithLibc.override { inherit (self.llvmPackages) libcxx; }
          );
      };

      extraNativeBuildInputs = lib.optionals localSystem.isAarch64 [
        prevStage.updateAutotoolsGnuConfigScriptsHook
        prevStage.gnu-config
      ];

      extraPreHook = ''
        stripDebugFlags="-S" # llvm-strip does not support "-p" for Mach-O
      '';
    }
  )

  # Rebuild LLVM with LLVM. This stage also rebuilds certain dependencies needed by LLVM.
  #
  # LLVM requires: libcxx libffi libiconv libxml2 ncurses python3 zlib
  (
    prevStage:
    # previous stage2 stdenv:
    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage;
      [
        autoconf
        automake
        bison
        brotli
        cctools
        cmake
        cmakeMinimal
        coreutils
        cpio
        cyrus_sasl
        db
        ed
        expat
        flex
        gettext
        gmp
        gnugrep
        groff
        icu
        ld64
        libedit
        libffi
        libiconv
        libidn2
        libkrb5
        libssh2
        libtool
        libtapi
        libunistring
        libxml2
        m4
        meson
        ncurses
        nghttp2
        ninja
        openbsm
        openldap
        openpam
        openssh
        openssl
        patchutils
        pbzx
        perl
        pkg-config.pkg-config
        python3
        python3Minimal
        scons
        serf
        sqlite
        subversion
        sysctl.provider
        texinfo
        unzip
        which
        xz
        zstd
        zlib
      ]
    );
    assert lib.all isBuiltByNixpkgsCompiler (with prevStage; [ bash ]);

    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage.darwin;
      [
        locale
        print-reexports
        rewrite-tbd
        sigtool
      ]
    );

    assert
      (!useAppleSDKLibs) -> lib.all isBuiltByBootstrapFilesCompiler (with prevStage.darwin; [ configd ]);
    assert
      (!useAppleSDKLibs) -> lib.all isBuiltByNixpkgsCompiler (with prevStage.darwin; [ Libsystem ]);
    assert (!useAppleSDKLibs) -> lib.all isFromNixpkgs (with prevStage.darwin; [ CF ]);
    assert
      useAppleSDKLibs
      -> lib.all isFromNixpkgs (
        with prevStage.darwin;
        [
          CF
          Libsystem
          libobjc
        ]
      );
    assert lib.all isFromNixpkgs (
      with prevStage.darwin;
      [
        binutils-unwrapped
        dyld
        launchd
        libclosure
        libdispatch
        xnu
      ]
    );

    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage.llvmPackages;
      [
        clang-unwrapped
        libclang
        libllvm
        llvm
      ]
    );
    assert lib.all isBuiltByNixpkgsCompiler (with prevStage.llvmPackages; [ libcxx ]);

    stageFun prevStage {

      name = "bootstrap-stage3";

      overrides = self: super: {
        inherit (prevStage)
          ccWrapperStdenv
          autoconf
          automake
          bash
          binutils-unwrapped
          bison
          brotli
          cmake
          cmakeMinimal
          coreutils
          cpio
          curl
          cyrus_sasl
          db
          ed
          expat
          flex
          gettext
          gmp
          gnugrep
          groff
          libedit
          libidn2
          libkrb5
          libssh2
          libtool
          libunistring
          m4
          meson
          nghttp2
          ninja
          openbsm
          openldap
          openpam
          openssh
          openssl
          patchutils
          pbzx
          perl
          pkg-config
          python3
          python3Minimal
          scons
          sed
          serf
          sharutils
          sqlite
          subversion
          sysctl
          texinfo
          unzip
          which
          xz
          zstd
          ;

        # Disable tests because they use dejagnu, which fails to run.
        libffi = super.libffi.override { doCheck = false; };

        # Avoid pulling in a full python and its extra dependencies for the llvm/clang builds.
        libxml2 = super.libxml2.override { pythonSupport = false; };

        darwin = super.darwin.overrideScope (
          selfDarwin: superDarwin: {
            inherit (prevStage.darwin)
              CF
              Libsystem
              binutils
              binutils-unwrapped
              configd
              darwin-stubs
              dyld
              launchd
              libclosure
              libdispatch
              libobjc
              locale
              objc4
              postLinkSignHook
              print-reexports
              rewrite-tbd
              signingUtils
              sigtool
              ;

            apple_sdk = superDarwin.apple_sdk // {
              inherit (prevStage.darwin.apple_sdk) sdkRoot;
            };
          }
        );

        llvmPackages =
          super.llvmPackages
          // (
            let
              libraries = super.llvmPackages.libraries.extend (
                _: _: { inherit (prevStage.llvmPackages) compiler-rt libcxx; }
              );
            in
            { inherit libraries; } // libraries
          );
      };

      extraNativeBuildInputs = lib.optionals localSystem.isAarch64 [
        prevStage.updateAutotoolsGnuConfigScriptsHook
        prevStage.gnu-config
      ];

      extraPreHook = ''
        stripDebugFlags="-S" # llvm-strip does not support "-p" for Mach-O
      '';
    }
  )

  # Construct a standard environment with the new clang. Also use the new compiler to rebuild
  # everything that will be part of the final stdenv and isn’t required by it, CF, or Libsystem.
  (
    prevStage:
    # previous stage3 stdenv:
    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage;
      [
        autoconf
        automake
        bison
        brotli
        cmake
        cmakeMinimal
        coreutils
        cpio
        cyrus_sasl
        db
        ed
        expat
        flex
        gettext
        gmp
        gnugrep
        groff
        libedit
        libidn2
        libkrb5
        libssh2
        libtool
        libunistring
        m4
        meson
        nghttp2
        ninja
        openbsm
        openldap
        openpam
        openssh
        openssl
        patchutils
        pbzx
        perl
        pkg-config.pkg-config
        python3
        python3Minimal
        scons
        serf
        sqlite
        subversion
        sysctl.provider
        texinfo
        unzip
        which
        xz
        zstd
      ]
    );

    assert lib.all isBuiltByNixpkgsCompiler (
      with prevStage;
      [
        bash
        cctools
        icu
        ld64
        libtapi
        libffi
        libiconv
        libxml2
        zlib
      ]
    );

    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage.darwin;
      [
        locale
        print-reexports
        rewrite-tbd
        sigtool
      ]
    );

    assert
      (!useAppleSDKLibs) -> lib.all isBuiltByBootstrapFilesCompiler (with prevStage.darwin; [ configd ]);
    assert
      (!useAppleSDKLibs) -> lib.all isBuiltByNixpkgsCompiler (with prevStage.darwin; [ Libsystem ]);
    assert (!useAppleSDKLibs) -> lib.all isFromNixpkgs (with prevStage.darwin; [ CF ]);
    assert
      useAppleSDKLibs
      -> lib.all isFromNixpkgs (
        with prevStage.darwin;
        [
          CF
          Libsystem
          libobjc
        ]
      );
    assert lib.all isFromNixpkgs (
      with prevStage.darwin;
      [
        binutils-unwrapped
        dyld
        launchd
        libclosure
        libdispatch
        xnu
      ]
    );

    assert lib.all isBuiltByNixpkgsCompiler (
      with prevStage.llvmPackages;
      [
        clang-unwrapped
        libclang
        libllvm
        llvm
        compiler-rt
        libcxx
      ]
    );

    stageFun prevStage {

      name = "bootstrap-stage4";

      overrides = self: super: {
        inherit (prevStage)
          ccWrapperStdenv
          autoconf
          automake
          bash
          binutils-unwrapped
          bison
          cmake
          cmakeMinimal
          curl
          cyrus_sasl
          db
          expat
          flex
          groff
          libedit
          libtool
          m4
          meson
          ninja
          openldap
          openssh
          patchutils
          perl
          pkg-config
          python3
          python3Minimal
          scons
          serf
          sqlite
          subversion
          sysctl
          texinfo
          unzip
          which

          # CF dependencies - don’t rebuild them.
          icu

          # LLVM dependencies - don’t rebuild them.
          libffi
          libiconv
          libiconv-darwin
          libxml2
          ncurses
          zlib
          ;

        darwin = super.darwin.overrideScope (
          selfDarwin: superDarwin: {
            inherit (prevStage.darwin)
              dyld
              CF
              Libsystem
              darwin-stubs
              # CF dependencies - don’t rebuild them.
              libobjc
              objc4
              ;

            apple_sdk = superDarwin.apple_sdk // {
              inherit (prevStage.darwin.apple_sdk) sdkRoot;
            };

            signingUtils = superDarwin.signingUtils.override { inherit (selfDarwin) sigtool; };

            binutils = superDarwin.binutils.override {
              inherit (prevStage) expand-response-params;

              bintools = selfDarwin.binutils-unwrapped;
              libc = selfDarwin.Libsystem;
            };

            # binutils-unwrapped needs to build the LLVM man pages, which requires a lot of Python stuff
            # that ultimately ends up depending on git. Fortunately, the git dependency is only for check
            # inputs. The following set of overrides allow the LLVM documentation to be built without
            # pulling curl (and other packages like ffmpeg) into the stdenv bootstrap.
            binutils-unwrapped = superDarwin.binutils-unwrapped.override (old: {
              llvm-manpages = super.llvmPackages.llvm-manpages.override {
                python3Packages = self.python3.pkgs.overrideScope (
                  _: superPython: {
                    hatch-vcs = superPython.hatch-vcs.overrideAttrs { doInstallCheck = false; };
                    markdown-it-py = superPython.markdown-it-py.overrideAttrs { doInstallCheck = false; };
                    mdit-py-plugins = superPython.mdit-py-plugins.overrideAttrs { doInstallCheck = false; };
                    myst-parser = superPython.myst-parser.overrideAttrs { doInstallCheck = false; };
                  }
                );
              };
            });
          }
        );

        llvmPackages =
          super.llvmPackages
          // (
            let
              tools = super.llvmPackages.tools.extend (
                _: _: {
                  inherit (prevStage.llvmPackages)
                    clang-unwrapped
                    libclang
                    libllvm
                    llvm
                    ;
                  libcxxClang = lib.makeOverridable (import ../../build-support/cc-wrapper) {
                    nativeTools = false;
                    nativeLibc = false;

                    inherit (prevStage) expand-response-params;

                    extraPackages = [ self.llvmPackages.compiler-rt ];

                    extraBuildCommands =
                      let
                        inherit (self.llvmPackages) clang-unwrapped compiler-rt release_version;

                        # Clang 16+ uses only the major version in resource-root, but older versions use the complete one.
                        clangResourceRootIncludePath =
                          clangLib: clangRelease:
                          let
                            clangVersion =
                              if lib.versionAtLeast clangRelease "16" then lib.versions.major clangRelease else clangRelease;
                          in
                          "${clangLib}/lib/clang/${clangVersion}/include";
                      in
                      ''
                        rsrc="$out/resource-root"
                        mkdir "$rsrc"
                        ln -s "${clangResourceRootIncludePath clang-unwrapped.lib release_version}" "$rsrc"
                        ln -s "${compiler-rt.out}/lib"   "$rsrc/lib"
                        ln -s "${compiler-rt.out}/share" "$rsrc/share"
                        echo "-resource-dir=$rsrc" >> $out/nix-support/cc-cflags
                      '';

                    cc = self.llvmPackages.clang-unwrapped;
                    bintools = self.darwin.binutils;

                    isClang = true;
                    libc = self.darwin.Libsystem;
                    inherit (self.llvmPackages) libcxx;

                    inherit lib;
                    inherit (self)
                      stdenvNoCC
                      coreutils
                      gnugrep
                      runtimeShell
                      ;
                  };
                }
              );
              libraries = super.llvmPackages.libraries.extend (
                _: _: { inherit (prevStage.llvmPackages) compiler-rt libcxx; }
              );
            in
            { inherit tools libraries; } // tools // libraries
          );
      };

      extraNativeBuildInputs = lib.optionals localSystem.isAarch64 [
        prevStage.updateAutotoolsGnuConfigScriptsHook
        prevStage.gnu-config
      ];

      extraPreHook = ''
        stripDebugFlags="-S" # llvm-strip does not support "-p" for Mach-O
      '';
    }
  )

  # Construct the final stdenv. The version of LLVM provided should match the one defined in
  # `all-packages.nix` for Darwin. Nothing should depend on the bootstrap tools or originate from
  # the bootstrap tools.
  #
  # When updating the Darwin stdenv, make sure that the result has no dependency (`nix-store -qR`)
  # on `bootstrapTools` or the binutils built in stage 1.
  (
    prevStage:
    # previous stage4 stdenv:
    assert lib.all isBuiltByNixpkgsCompiler (
      with prevStage;
      [
        bash
        brotli
        bzip2
        cctools
        cpio
        diffutils
        ed
        file
        findutils
        gawk
        gettext
        gmp
        gnugrep
        gnumake
        gnused
        gnutar
        gzip
        icu
        ld64
        libffi
        libiconv
        libidn2
        libkrb5
        libssh2
        libtapi
        libunistring
        libxml2
        libyaml
        ncurses
        nghttp2
        openbsm
        openpam
        openssl
        patch
        pbzx
        pcre
        xar
        xz
        zlib
        zstd
      ]
    );

    assert lib.all isBuiltByNixpkgsCompiler (
      with prevStage.darwin;
      [
        locale
        print-reexports
        rewrite-tbd
        sigtool
      ]
    );

    assert
      (!useAppleSDKLibs)
      -> lib.all isBuiltByNixpkgsCompiler (
        with prevStage.darwin;
        [
          Libsystem
          configd
        ]
      );
    assert (!useAppleSDKLibs) -> lib.all isFromNixpkgs (with prevStage.darwin; [ CF ]);
    assert
      useAppleSDKLibs
      -> lib.all isFromNixpkgs (
        with prevStage.darwin;
        [
          CF
          Libsystem
          libobjc
        ]
      );
    assert lib.all isFromNixpkgs (
      with prevStage.darwin;
      [
        binutils-unwrapped
        dyld
        launchd
        libclosure
        libdispatch
        xnu
      ]
    );

    assert lib.all isBuiltByNixpkgsCompiler (
      with prevStage.llvmPackages;
      [
        clang-unwrapped
        libclang
        libllvm
        llvm
        compiler-rt
        libcxx
      ]
    );

    assert lib.all isBuiltByBootstrapFilesCompiler (
      with prevStage;
      [
        autoconf
        automake
        bison
        cmake
        cmakeMinimal
        cyrus_sasl
        db
        expat
        flex
        groff
        libedit
        libtool
        m4
        meson
        ninja
        openldap
        openssh
        patchutils
        perl
        pkg-config.pkg-config
        python3
        python3Minimal
        scons
        serf
        sqlite
        subversion
        sysctl.provider
        texinfo
        unzip
        which
      ]
    );

    let
      cc = prevStage.llvmPackages.clang;
    in
    {
      inherit config overlays;
      stdenv = import ../generic {
        name = "stdenv-darwin";

        buildPlatform = localSystem;
        hostPlatform = localSystem;
        targetPlatform = localSystem;

        inherit config;

        preHook = ''
          ${commonPreHook}
          stripDebugFlags="-S" # llvm-strip does not support "-p" for Mach-O
          export PATH_LOCALE=${prevStage.darwin.locale}/share/locale
        '';

        initialPath = ((import ../generic/common-path.nix) { pkgs = prevStage; });

        extraNativeBuildInputs =
          lib.optionals localSystem.isAarch64 [ prevStage.updateAutotoolsGnuConfigScriptsHook ]
          ++ [ prevStage.darwin.apple_sdk.sdkRoot ];

        extraBuildInputs = [ prevStage.darwin.CF ];

        inherit cc;

        shell = cc.shell;

        inherit (prevStage.stdenv) fetchurlBoot;

        extraAttrs =
          {
            inherit bootstrapTools;
            libc = prevStage.darwin.Libsystem;
            shellPackage = prevStage.bash;
          }
          // lib.optionalAttrs useAppleSDKLibs {
            # This objc4 will be propagated to all builds using the final stdenv,
            # and we shouldn't mix different builds, because they would be
            # conflicting LLVM modules. Export it here so we can grab it later.
            inherit (prevStage.darwin) objc4;
          };

        disallowedRequisites = [ bootstrapTools.out ];

        allowedRequisites =
          (with prevStage; [
            bash
            bzip2.bin
            bzip2.out
            cc.expand-response-params
            cctools
            ld64.out
            ld64.lib
            libtapi.out
            coreutils
            darwin.binutils
            darwin.binutils.bintools
            diffutils
            ed
            file
            findutils
            gawk
            gettext
            gmp.out
            gnugrep
            gnugrep.pcre2.out
            gnumake
            gnused
            gnutar
            gzip
            icu.out
            libffi.out
            libiconv
            libunistring.out
            libxml2.out
            ncurses.dev
            ncurses.man
            ncurses.out
            openbsm
            openpam
            openssl.out
            patch
            xar
            xz.bin
            xz.out
            zlib.dev
            zlib.out
          ])
          ++ lib.optionals localSystem.isAarch64 [
            prevStage.updateAutotoolsGnuConfigScriptsHook
            prevStage.gnu-config
          ]
          ++ (with prevStage.llvmPackages; [
            bintools-unwrapped
            clang-unwrapped
            clang-unwrapped.lib
            compiler-rt
            compiler-rt.dev
            libcxx
            libcxx.dev
            lld
            llvm
            llvm.lib
          ])
          ++ (
            with prevStage.darwin;
            [
              CF
              Libsystem
              dyld
              locale
              apple_sdk.sdkRoot
            ]
            ++ lib.optionals useAppleSDKLibs [ objc4 ]
          );

        __stdenvImpureHostDeps = commonImpureHostDeps;
        __extraImpureHostDeps = commonImpureHostDeps;

        overrides =
          self: super:
          {
            inherit (prevStage)
              bash
              brotli
              bzip2
              coreutils
              cpio
              diffutils
              ed
              file
              findutils
              gawk
              gettext
              gmp
              gnugrep
              gnumake
              gnused
              gnutar
              gzip
              icu
              libffi
              libiconv
              libiconv-darwin
              libidn2
              libssh2
              libunistring
              libxml2
              libyaml
              ncurses
              nghttp2
              openbsm
              openpam
              openssl
              patch
              pbzx
              pcre
              python3Minimal
              xar
              xz
              zlib
              zstd
              ;

            darwin = super.darwin.overrideScope (
              _: superDarwin:
              {
                inherit (prevStage.darwin)
                  CF
                  Libsystem
                  darwin-stubs
                  dyld
                  locale
                  libobjc
                  rewrite-tbd
                  xnu
                  ;

                apple_sdk = superDarwin.apple_sdk // {
                  inherit (prevStage.darwin.apple_sdk) sdkRoot;
                };
              }
              // lib.optionalAttrs (super.stdenv.targetPlatform == localSystem) {
                inherit (prevStage.darwin) binutils binutils-unwrapped;
              }
            );
          }
          // lib.optionalAttrs (super.stdenv.targetPlatform == localSystem) {
            inherit (prevStage) cctools ld64 libtapi;
            inherit (prevStage.llvmPackages) clang llvm;

            # Need to get rid of these when cross-compiling.
            llvmPackages =
              super.llvmPackages
              // (
                let
                  tools = super.llvmPackages.tools.extend (
                    _: _: {
                      inherit (prevStage.llvmPackages)
                        clang
                        clang-unwrapped
                        libclang
                        libllvm
                        llvm
                        ;
                    }
                  );
                  libraries = super.llvmPackages.libraries.extend (
                    _: _: { inherit (prevStage.llvmPackages) compiler-rt libcxx; }
                  );
                in
                { inherit tools libraries; } // tools // libraries
              );
          };
      };
    }
  )

  # This "no-op" stage is just a place to put the assertions about the final stage.
  (
    prevStage:
    # previous final stage stdenv:
    assert isBuiltByNixpkgsCompiler prevStage.cctools;
    assert isBuiltByNixpkgsCompiler prevStage.ld64;
    assert isBuiltByNixpkgsCompiler prevStage.darwin.sigtool;
    assert isBuiltByNixpkgsCompiler prevStage.darwin.print-reexports;
    assert isBuiltByNixpkgsCompiler prevStage.darwin.rewrite-tbd;

    assert isFromNixpkgs prevStage.darwin.CF;
    assert isFromNixpkgs prevStage.darwin.Libsystem;
    assert isFromNixpkgs prevStage.darwin.binutils-unwrapped;

    assert isBuiltByNixpkgsCompiler prevStage.llvmPackages.clang-unwrapped;
    assert isBuiltByNixpkgsCompiler prevStage.llvmPackages.libllvm;
    assert isBuiltByNixpkgsCompiler prevStage.llvmPackages.libcxx;
    assert isBuiltByNixpkgsCompiler prevStage.llvmPackages.compiler-rt;

    # Make sure these evaluate since they were disabled explicitly in the bootstrap.
    assert isBuiltByNixpkgsCompiler prevStage.binutils-unwrapped;
    assert isFromNixpkgs prevStage.binutils-unwrapped.src;
    assert isBuiltByNixpkgsCompiler prevStage.curl;

    {
      inherit (prevStage) config overlays stdenv;
    }
  )
]