swift: compiler only build & darwin support

pkgs/development/compilers/swift/compiler/default.nix

···
+{ lib
+, stdenv
+, cmake
+, coreutils
+, gnugrep
+, perl
+, ninja
+, pkg-config
+, clang
+, bintools
+, python3
+, git
+, fetchFromGitHub
+, fetchpatch
+, makeWrapper
+, gnumake
+, file
+, runCommand
+, writeShellScriptBin
+# For lldb
+, libedit
+, ncurses
+, swig
+, libxml2
+# Linux-specific
+, glibc
+, libuuid
+# Darwin-specific
+, substituteAll
+, fixDarwinDylibNames
+, runCommandLocal
+, xcbuild
+, cctools # libtool
+, sigtool
+, DarwinTools
+, CoreServices
+, Foundation
+, Combine
+, CLTools_Executables
+}:
+
+let
+
+  inherit (stdenv) hostPlatform targetPlatform;
+
+  # The Swift toolchain script builds projects with separate repos. By convention, some of them share
+  # the same version with the main Swift compiler project per release.
+  version = "5.7";
+
+  fetchSwiftRelease = { repo, hash }:
+    fetchFromGitHub {
+      owner = "apple";
+      inherit repo hash;
+      rev = "swift-${version}-RELEASE";
+      name = "${repo}-${version}-src";
+    };
+
+  # Names in this set match the directory the source is unpacked to.
+  sources = {
+    cmark = fetchSwiftRelease {
+      repo = "swift-cmark";
+      hash = "sha256-f0BoTs4HYdx/aJ9HIGCWMalhl8PvClWD6R4QK3qSgAw=";
+    };
+    llvm-project = fetchSwiftRelease {
+      repo = "llvm-project";
+      hash = "sha256-uW6dEAFaDOlHXnq8lFYxrKNLRPEukauZJxX4UCpWpIY=";
+    };
+    swift = fetchSwiftRelease {
+      repo = "swift";
+      hash = "sha256-n8WVQYinAyIj4wmQnDhvPsH+t8ydANkGbjFJ6blfHOY=";
+    };
+    swift-experimental-string-processing = fetchSwiftRelease {
+      repo = "swift-experimental-string-processing";
+      hash = "sha256-Ar9fQWi8bYSvGErrS0SWrxIxwEwCjsYIZcWweZ8bV28=";
+    };
+  }
+    // lib.optionalAttrs (!stdenv.isDarwin) {
+      swift-corelibs-libdispatch = fetchSwiftRelease {
+        repo = "swift-corelibs-libdispatch";
+        hash = "sha256-1qbXiC1k9+T+L6liqXKg6EZXqem6KEEx8OctuL4Kb2o=";
+      };
+    };
+
+  # Tools invoked by swift at run-time.
+  runtimeDeps = lib.optionals stdenv.isDarwin [
+    # libtool is used for static linking. This is part of cctools, but adding
+    # that as a build input puts an unwrapped linker in PATH, and breaks
+    # builds. This small derivation exposes just libtool.
+    # NOTE: The same applies to swift-driver, but that is currently always
+    # invoked via the old `swift` / `swiftc`. May change in the future.
+    (runCommandLocal "libtool" { } ''
+      mkdir -p $out/bin
+      ln -s ${cctools}/bin/libtool $out/bin/libtool
+    '')
+  ];
+
+  # There are apparently multiple naming conventions on Darwin. Swift uses the
+  # xcrun naming convention. See `configure_sdk_darwin` calls in CMake files.
+  swiftOs = if targetPlatform.isDarwin
+    then {
+      "macos" = "macosx";
+      "ios" = "iphoneos";
+      #iphonesimulator
+      #appletvos
+      #appletvsimulator
+      #watchos
+      #watchsimulator
+    }.${targetPlatform.darwinPlatform}
+      or (throw "Cannot build Swift for target Darwin platform '${targetPlatform.darwinPlatform}'")
+    else targetPlatform.parsed.kernel.name;
+
+  # Apple Silicon uses a different CPU name in the target triple.
+  swiftArch = if stdenv.isDarwin && stdenv.isAarch64 then "arm64"
+    else targetPlatform.parsed.cpu.name;
+
+  # On Darwin, a `.swiftmodule` is a subdirectory in `lib/swift/<OS>`,
+  # containing binaries for supported archs. On other platforms, binaries are
+  # installed to `lib/swift/<OS>/<ARCH>`. Note that our setup-hook also adds
+  # `lib/swift` for convenience.
+  swiftLibSubdir = "lib/swift/${swiftOs}";
+  swiftModuleSubdir = if hostPlatform.isDarwin
+    then "lib/swift/${swiftOs}"
+    else "lib/swift/${swiftOs}/${swiftArch}";
+
+  # And then there's also a separate subtree for statically linked  modules.
+  toStaticSubdir = lib.replaceStrings [ "/swift/" ] [ "/swift_static/" ];
+  swiftStaticLibSubdir = toStaticSubdir swiftLibSubdir;
+  swiftStaticModuleSubdir = toStaticSubdir swiftModuleSubdir;
+
+  # This matches _SWIFT_DEFAULT_COMPONENTS, with specific components disabled.
+  swiftInstallComponents = [
+    "autolink-driver"
+    "compiler"
+    # "clang-builtin-headers"
+    "stdlib"
+    "sdk-overlay"
+    "parser-lib"
+    "static-mirror-lib"
+    "editor-integration"
+    # "tools"
+    # "testsuite-tools"
+    "toolchain-tools"
+    "toolchain-dev-tools"
+    "license"
+    (if stdenv.isDarwin then "sourcekit-xpc-service" else "sourcekit-inproc")
+    "swift-remote-mirror"
+    "swift-remote-mirror-headers"
+  ];
+
+  # Build a tool used during the build to create a custom clang wrapper, with
+  # which we wrap the clang produced by the swift build.
+  #
+  # This is used in a `POST_BUILD` for the CMake target, so we rename the
+  # actual clang to clang-unwrapped, then put the wrapper in place.
+  #
+  # We replace the `exec ...` command with `exec -a "$0"` in order to
+  # preserve $0 for clang. This is because, unlike Nix, we don't have
+  # separate wrappers for clang/clang++, and clang uses $0 to detect C++.
+  #
+  # Similarly, the C++ detection in the wrapper itself also won't work for us,
+  # so we base it on $0 as well.
+  makeClangWrapper = writeShellScriptBin "nix-swift-make-clang-wrapper" ''
+    set -euo pipefail
+
+    targetFile="$1"
+    unwrappedClang="$targetFile-unwrapped"
+
+    mv "$targetFile" "$unwrappedClang"
+    sed < '${clang}/bin/clang' > "$targetFile" \
+      -e 's|^\s*exec|exec -a "$0"|g' \
+      -e 's|^\[\[ "${clang.cc}/bin/clang" = \*++ ]]|[[ "$0" = *++ ]]|' \
+      -e "s|${clang.cc}/bin/clang|$unwrappedClang|g"
+    chmod a+x "$targetFile"
+  '';
+
+  # Create a tool used during the build to create a custom swift wrapper for
+  # each of the swift executables produced by the build.
+  #
+  # The build produces several `swift-frontend` executables during
+  # bootstrapping. Each of these has numerous aliases via symlinks, and the
+  # executable uses $0 to detect what tool is called.
+  wrapperParams = {
+    inherit bintools;
+    default_cc_wrapper = clang; # Instead of `@out@` in the original.
+    coreutils_bin = lib.getBin coreutils;
+    gnugrep_bin = gnugrep;
+    suffixSalt = lib.replaceStrings ["-" "."] ["_" "_"] targetPlatform.config;
+    use_response_file_by_default = 1;
+    # NOTE: @prog@ needs to be filled elsewhere.
+  };
+  swiftWrapper = runCommand "swift-wrapper.sh" wrapperParams ''
+    substituteAll '${../wrapper/wrapper.sh}' "$out"
+  '';
+  makeSwiftcWrapper = writeShellScriptBin "nix-swift-make-swift-wrapper" ''
+    set -euo pipefail
+
+    targetFile="$1"
+    unwrappedSwift="$targetFile-unwrapped"
+
+    mv "$targetFile" "$unwrappedSwift"
+    sed < '${swiftWrapper}' > "$targetFile" \
+      -e "s|@prog@|'$unwrappedSwift'|g" \
+      -e 's|exec "$prog"|exec -a "$0" "$prog"|g'
+    chmod a+x "$targetFile"
+  '';
+
+in stdenv.mkDerivation {
+  pname = "swift";
+  inherit version;
+
+  outputs = [ "out" "lib" "dev" "doc" "man" ];
+
+  nativeBuildInputs = [
+    cmake
+    git
+    ninja
+    perl # pod2man
+    pkg-config
+    python3
+    makeWrapper
+    makeClangWrapper
+    makeSwiftcWrapper
+  ]
+    ++ lib.optionals stdenv.isDarwin [
+      xcbuild
+      sigtool # codesign
+      DarwinTools # sw_vers
+      fixDarwinDylibNames
+    ];
+
+  buildInputs = [
+    # For lldb
+    python3
+    swig
+    libxml2
+  ]
+    ++ lib.optionals stdenv.isLinux [
+      libuuid
+    ]
+    ++ lib.optionals stdenv.isDarwin [
+      CoreServices
+      Foundation
+      Combine
+    ];
+
+  # This is a partial reimplementation of our setup hook. Because we reuse
+  # the Swift wrapper for the Swift build itself, we need to do some of the
+  # same preparation.
+  postHook = ''
+    for pkg in "''${pkgsHostTarget[@]}" '${clang.libc}'; do
+      for subdir in ${swiftModuleSubdir} ${swiftStaticModuleSubdir} lib/swift; do
+        if [[ -d "$pkg/$subdir" ]]; then
+          export NIX_SWIFTFLAGS_COMPILE+=" -I $pkg/$subdir"
+        fi
+      done
+      for subdir in ${swiftLibSubdir} ${swiftStaticLibSubdir} lib/swift; do
+        if [[ -d "$pkg/$subdir" ]]; then
+          export NIX_LDFLAGS+=" -L $pkg/$subdir"
+        fi
+      done
+    done
+  '';
+
+  # We invoke cmakeConfigurePhase multiple times, but only need this once.
+  dontFixCmake = true;
+  # We setup custom build directories.
+  dontUseCmakeBuildDir = true;
+
+  unpackPhase = ''
+    mkdir src
+    cd src
+
+    ${lib.concatStrings (lib.mapAttrsToList (dir: src: ''
+      cp -r ${src} ${dir}
+    '') sources)}
+
+    chmod -R u+w .
+  '';
+
+  patchPhase = ''
+    # Just patch all the things for now, we can focus this later.
+    # TODO: eliminate use of env.
+    find -type f -print0 | xargs -0 sed -i \
+    ${lib.optionalString stdenv.isDarwin
+      "-e 's|/usr/libexec/PlistBuddy|${xcbuild}/bin/PlistBuddy|g'"} \
+      -e 's|/usr/bin/env|${coreutils}/bin/env|g' \
+      -e 's|/usr/bin/make|${gnumake}/bin/make|g' \
+      -e 's|/bin/mkdir|${coreutils}/bin/mkdir|g' \
+      -e 's|/bin/cp|${coreutils}/bin/cp|g' \
+      -e 's|/usr/bin/file|${file}/bin/file|g'
+
+    patch -p1 -d swift -i ${./patches/swift-wrap.patch}
+    patch -p1 -d swift -i ${./patches/swift-nix-resource-root.patch}
+    patch -p1 -d swift -i ${./patches/swift-linux-fix-linking.patch}
+    patch -p1 -d swift -i ${./patches/swift-darwin-fix-bootstrap.patch}
+    patch -p1 -d swift -i ${substituteAll {
+      src = ./patches/swift-darwin-plistbuddy-workaround.patch;
+      inherit swiftArch;
+    }}
+    patch -p1 -d swift -i ${substituteAll {
+      src = ./patches/swift-prevent-sdk-dirs-warning.patch;
+      inherit (builtins) storeDir;
+    }}
+    substituteInPlace swift/cmake/modules/SwiftConfigureSDK.cmake \
+      --replace '/usr/include' "${stdenv.cc.libc_dev}/include"
+
+    # This patch needs to know the lib output location, so must be substituted
+    # in the same derivation as the compiler.
+    storeDir="${builtins.storeDir}" \
+      substituteAll ${./patches/swift-separate-lib.patch} $TMPDIR/swift-separate-lib.patch
+    patch -p1 -d swift -i $TMPDIR/swift-separate-lib.patch
+
+    patch -p1 -d llvm-project/llvm -i ${./patches/llvm-module-cache.patch}
+
+    patch -p1 -d llvm-project/clang -i ${./patches/clang-toolchain-dir.patch}
+    patch -p1 -d llvm-project/clang -i ${./patches/clang-wrap.patch}
+    patch -p1 -d llvm-project/clang -i ${../../llvm/14/clang/purity.patch}
+    patch -p2 -d llvm-project/clang -i ${fetchpatch {
+      name = "clang-cmake-fix-interpreter.patch";
+      url = "https://github.com/llvm/llvm-project/commit/b5eaf500f2441eff2277ea2973878fb1f171fd0a.patch";
+      sha256 = "1rma1al0rbm3s3ql6bnvbcighp74lri1lcrwbyacgdqp80fgw1b6";
+    }}
+
+    ${lib.optionalString stdenv.isLinux ''
+    substituteInPlace llvm-project/clang/lib/Driver/ToolChains/Linux.cpp \
+      --replace 'SysRoot + "/lib' '"${glibc}/lib" "' \
+      --replace 'SysRoot + "/usr/lib' '"${glibc}/lib" "' \
+      --replace 'LibDir = "lib";' 'LibDir = "${glibc}/lib";' \
+      --replace 'LibDir = "lib64";' 'LibDir = "${glibc}/lib";' \
+      --replace 'LibDir = X32 ? "libx32" : "lib64";' 'LibDir = "${glibc}/lib";'
+
+    # uuid.h is not part of glibc, but of libuuid.
+    sed -i 's|''${GLIBC_INCLUDE_PATH}/uuid/uuid.h|${libuuid.dev}/include/uuid/uuid.h|' \
+      swift/stdlib/public/Platform/glibc.modulemap.gyb
+    ''}
+
+    # Remove tests for cross compilation, which we don't currently support.
+    rm swift/test/Interop/Cxx/class/constructors-copy-irgen.swift
+    rm swift/test/Interop/Cxx/class/constructors-irgen.swift
+
+    # TODO: consider fixing and re-adding. This test fails due to a non-standard "install_prefix".
+    rm swift/validation-test/Python/build_swift.swift
+
+    # We cannot handle the SDK location being in "Weird Location" due to Nix isolation.
+    rm swift/test/DebugInfo/compiler-flags.swift
+
+    # TODO: Fix issue with ld.gold invoked from script finding crtbeginS.o and crtendS.o.
+    rm swift/test/IRGen/ELF-remove-autolink-section.swift
+
+    # The following two tests fail because we use don't use the bundled libicu:
+    # [SOURCE_DIR/utils/build-script] ERROR: can't find source directory for libicu (tried /build/src/icu)
+    rm swift/validation-test/BuildSystem/default_build_still_performs_epilogue_opts_after_split.test
+    rm swift/validation-test/BuildSystem/test_early_swift_driver_and_infer.swift
+
+    # TODO: This test fails for some unknown reason
+    rm swift/test/Serialization/restrict-swiftmodule-to-revision.swift
+
+    # This test was flaky in ofborg, see #186476
+    rm swift/test/AutoDiff/compiler_crashers_fixed/sr14290-missing-debug-scopes-in-pullback-trampoline.swift
+
+    patchShebangs .
+
+    ${lib.optionalString (!stdenv.isDarwin) ''
+    # NOTE: This interferes with ABI stability on Darwin, which uses the system
+    # libraries in the hardcoded path /usr/lib/swift.
+    fixCmakeFiles .
+    ''}
+  '';
+
+  configurePhase = ''
+    export SWIFT_SOURCE_ROOT="$PWD"
+    mkdir -p ../build
+    cd ../build
+    export SWIFT_BUILD_ROOT="$PWD"
+
+    # Most builds set a target, but LLDB doesn't. Harmless on non-Darwin.
+    export MACOSX_DEPLOYMENT_TARGET=10.15
+  '';
+
+  # These steps are derived from doing a normal build with.
+  #
+  #   ./swift/utils/build-toolchain test --dry-run
+  #
+  # But dealing with the custom Python build system is far more trouble than
+  # simply invoking CMake directly. Few variables it passes to CMake are
+  # actually required or non-default.
+  #
+  # Using CMake directly also allows us to split up the already large build,
+  # and package Swift components separately.
+  #
+  # Besides `--dry-run`, another good way to compare build changes between
+  # Swift releases is to diff the scripts:
+  #
+  #   git diff swift-5.6.3-RELEASE..swift-5.7-RELEASE -- utils/build*
+  #
+  buildPhase = ''
+    # Helper to build a subdirectory.
+    #
+    # Always reset cmakeFlags before calling this. The cmakeConfigurePhase
+    # amends flags and would otherwise keep expanding it.
+    function buildProject() {
+      mkdir -p $SWIFT_BUILD_ROOT/$1
+      cd $SWIFT_BUILD_ROOT/$1
+
+      cmakeDir=$SWIFT_SOURCE_ROOT/''${2-$1}
+      cmakeConfigurePhase
+
+      ninjaBuildPhase
+    }
+
+    cmakeFlags="-GNinja"
+    buildProject cmark
+
+    # Some notes:
+    # - The Swift build just needs Clang.
+    # - We can further reduce targets to just our targetPlatform.
+    cmakeFlags="
+      -GNinja
+      -DLLVM_ENABLE_PROJECTS=clang
+      -DLLVM_TARGETS_TO_BUILD=${{
+        "x86_64" = "X86";
+        "aarch64" = "AArch64";
+      }.${targetPlatform.parsed.cpu.name}}
+    "
+    buildProject llvm llvm-project/llvm
+
+    # Some notes:
+    # - Building with libswift defaults to OFF in CMake, but is enabled in
+    #   standard builds, so we enable it as well.
+    # - Experimental features are OFF by default in CMake, but some are
+    #   required to build the stdlib.
+    # - SWIFT_STDLIB_ENABLE_OBJC_INTEROP is set explicitely because its check
+    #   is buggy. (Uses SWIFT_HOST_VARIANT_SDK before initialized.)
+    #   Fixed in: https://github.com/apple/swift/commit/84083afef1de5931904d5c815d53856cdb3fb232
+    cmakeFlags="
+      -GNinja
+      -DBOOTSTRAPPING_MODE=BOOTSTRAPPING
+      -DSWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY=ON
+      -DLLVM_DIR=$SWIFT_BUILD_ROOT/llvm/lib/cmake/llvm
+      -DClang_DIR=$SWIFT_BUILD_ROOT/llvm/lib/cmake/clang
+      -DSWIFT_PATH_TO_CMARK_SOURCE=$SWIFT_SOURCE_ROOT/cmark
+      -DSWIFT_PATH_TO_CMARK_BUILD=$SWIFT_BUILD_ROOT/cmark
+      -DSWIFT_PATH_TO_LIBDISPATCH_SOURCE=$SWIFT_SOURCE_ROOT/swift-corelibs-libdispatch
+      -DEXPERIMENTAL_STRING_PROCESSING_SOURCE_DIR=$SWIFT_SOURCE_ROOT/swift-experimental-string-processing
+      -DSWIFT_INSTALL_COMPONENTS=${lib.concatStringsSep ";" swiftInstallComponents}
+      -DSWIFT_STDLIB_ENABLE_OBJC_INTEROP=${if stdenv.isDarwin then "ON" else "OFF"}
+    "
+    buildProject swift
+
+    # These are based on flags in `utils/build-script-impl`.
+    #
+    # LLDB_USE_SYSTEM_DEBUGSERVER=ON disables the debugserver build on Darwin,
+    # which requires a special signature.
+    #
+    # CMAKE_BUILD_WITH_INSTALL_NAME_DIR ensures we don't use rpath on Darwin.
+    #
+    # NOTE: On Darwin, we only want ncurses in the linker search path, because
+    # headers are part of libsystem. Adding its headers to the search path
+    # causes strange mixing and errors. Note that libedit propagates ncurses,
+    # so we add both manually here, instead of relying on setup hooks.
+    # TODO: Find a better way to prevent this conflict.
+    cmakeFlags="
+      -GNinja
+      -DLLDB_SWIFTC=$SWIFT_BUILD_ROOT/swift/bin/swiftc
+      -DLLDB_SWIFT_LIBS=$SWIFT_BUILD_ROOT/swift/lib/swift
+      -DLLVM_DIR=$SWIFT_BUILD_ROOT/llvm/lib/cmake/llvm
+      -DClang_DIR=$SWIFT_BUILD_ROOT/llvm/lib/cmake/clang
+      -DSwift_DIR=$SWIFT_BUILD_ROOT/swift/lib/cmake/swift
+      -DLLDB_ENABLE_CURSES=ON
+      -DLLDB_ENABLE_LIBEDIT=ON
+      -DLLDB_ENABLE_PYTHON=ON
+      -DLLDB_ENABLE_LZMA=OFF
+      -DLLDB_ENABLE_LUA=OFF
+      -DLLDB_INCLUDE_TESTS=OFF
+      -DCMAKE_BUILD_WITH_INSTALL_NAME_DIR=ON
+      ${lib.optionalString stdenv.isDarwin ''
+      -DLLDB_USE_SYSTEM_DEBUGSERVER=ON
+      ''}
+      -DLibEdit_INCLUDE_DIRS=${libedit.dev}/include
+      -DLibEdit_LIBRARIES=${libedit}/lib/libedit${stdenv.hostPlatform.extensions.sharedLibrary}
+      -DCURSES_INCLUDE_DIRS=${if stdenv.isDarwin then "/var/empty" else ncurses.dev}/include
+      -DCURSES_LIBRARIES=${ncurses}/lib/libncurses${stdenv.hostPlatform.extensions.sharedLibrary}
+      -DPANEL_LIBRARIES=${ncurses}/lib/libpanel${stdenv.hostPlatform.extensions.sharedLibrary}
+    ";
+    buildProject lldb llvm-project/lldb
+
+    ${lib.optionalString stdenv.isDarwin ''
+    # Need to do a standalone build of concurrency for Darwin back deployment.
+    # Based on: utils/swift_build_support/swift_build_support/products/backdeployconcurrency.py
+    cmakeFlags="
+      -GNinja
+      -DCMAKE_Swift_COMPILER=$SWIFT_BUILD_ROOT/swift/bin/swiftc
+
+      -DTOOLCHAIN_DIR=/var/empty
+      -DSWIFT_NATIVE_LLVM_TOOLS_PATH=${stdenv.cc}/bin
+      -DSWIFT_NATIVE_CLANG_TOOLS_PATH=${stdenv.cc}/bin
+      -DSWIFT_NATIVE_SWIFT_TOOLS_PATH=$SWIFT_BUILD_ROOT/swift/bin
+
+      -DCMAKE_CROSSCOMPILING=ON
+
+      -DBUILD_SWIFT_CONCURRENCY_BACK_DEPLOYMENT_LIBRARIES=ON
+      -DSWIFT_INCLUDE_TOOLS=OFF
+      -DSWIFT_BUILD_STDLIB_EXTRA_TOOLCHAIN_CONTENT=OFF
+      -DSWIFT_BUILD_TEST_SUPPORT_MODULES=OFF
+      -DSWIFT_BUILD_STDLIB=OFF
+      -DSWIFT_BUILD_DYNAMIC_STDLIB=OFF
+      -DSWIFT_BUILD_STATIC_STDLIB=OFF
+      -DSWIFT_BUILD_REMOTE_MIRROR=OFF
+      -DSWIFT_BUILD_SDK_OVERLAY=OFF
+      -DSWIFT_BUILD_DYNAMIC_SDK_OVERLAY=OFF
+      -DSWIFT_BUILD_STATIC_SDK_OVERLAY=OFF
+      -DSWIFT_INCLUDE_TESTS=OFF
+      -DSWIFT_BUILD_PERF_TESTSUITE=OFF
+
+      -DSWIFT_HOST_VARIANT_ARCH=${swiftArch}
+      -DBUILD_STANDALONE=ON
+
+      -DSWIFT_INSTALL_COMPONENTS=back-deployment
+
+      -DSWIFT_SDKS=${{
+        "macos" = "OSX";
+        "ios" = "IOS";
+        #IOS_SIMULATOR
+        #TVOS
+        #TVOS_SIMULATOR
+        #WATCHOS
+        #WATCHOS_SIMULATOR
+      }.${targetPlatform.darwinPlatform}}
+
+      -DLLVM_DIR=$SWIFT_BUILD_ROOT/llvm/lib/cmake/llvm
+
+      -DSWIFT_DEST_ROOT=$out
+      -DSWIFT_HOST_VARIANT_SDK=OSX
+
+      -DSWIFT_DARWIN_DEPLOYMENT_VERSION_OSX=10.15
+      -DSWIFT_DARWIN_DEPLOYMENT_VERSION_IOS=13.0
+      -DSWIFT_DARWIN_DEPLOYMENT_VERSION_MACCATALYST=13.0
+      -DSWIFT_DARWIN_DEPLOYMENT_VERSION_TVOS=13.0
+      -DSWIFT_DARWIN_DEPLOYMENT_VERSION_WATCHOS=6.0
+    "
+
+    # This depends on the special Clang build specific to the Swift branch.
+    # We also need to call a specific Ninja target.
+    export CC=$SWIFT_BUILD_ROOT/llvm/bin/clang
+    export CXX=$SWIFT_BUILD_ROOT/llvm/bin/clang++
+    ninjaFlags="back-deployment"
+
+    buildProject swift-concurrency-backdeploy swift
+
+    export CC=$NIX_CC/bin/clang
+    export CXX=$NIX_CC/bin/clang++
+    unset ninjaFlags
+  ''}
+  '';
+
+  # TODO: ~50 failing tests on x86_64-linux. Other platforms not checked.
+  doCheck = false;
+  checkInputs = [ file ];
+  # TODO: consider using stress-tester and integration-test.
+  checkPhase = ''
+    cd $SWIFT_BUILD_ROOT/swift
+    checkTarget=check-swift-all
+    ninjaCheckPhase
+    unset checkTarget
+  '';
+
+  installPhase = ''
+    # Undo the clang and swift wrapping we did for the build.
+    # (This happened via patches to cmake files.)
+    cd $SWIFT_BUILD_ROOT
+    mv llvm/bin/clang-14{-unwrapped,}
+    mv swift/bin/swift-frontend{-unwrapped,}
+
+    mkdir $out $lib
+
+    # Install clang binaries only. We hide these with the wrapper, so they are
+    # for private use by Swift only.
+    cd $SWIFT_BUILD_ROOT/llvm
+    installTargets=install-clang
+    ninjaInstallPhase
+    unset installTargets
+
+    # LLDB is also a private install.
+    cd $SWIFT_BUILD_ROOT/lldb
+    ninjaInstallPhase
+
+    cd $SWIFT_BUILD_ROOT/swift
+    ninjaInstallPhase
+
+    ${lib.optionalString stdenv.isDarwin ''
+    cd $SWIFT_BUILD_ROOT/swift-concurrency-backdeploy
+    installTargets=install-back-deployment
+    ninjaInstallPhase
+    unset installTargets
+    ''}
+
+    # Separate $lib output here, because specific logic follows.
+    # Only move the dynamic run-time parts, to keep $lib small. Every Swift
+    # build will depend on it.
+    moveToOutput "lib/swift" "$lib"
+    moveToOutput "lib/libswiftDemangle.*" "$lib"
+
+    # This link is here because various tools (swiftpm) check for stdlib
+    # relative to the swift compiler. It's fine if this is for build-time
+    # stuff, but we should patch all cases were it would end up in an output.
+    ln -s $lib/lib/swift $out/lib/swift
+
+    # Swift has a separate resource root from Clang, but locates the Clang
+    # resource root via subdir or symlink. Provide a default here, but we also
+    # patch Swift to prefer NIX_CC if set.
+    ln -s ${clang}/resource-root $lib/lib/swift/clang
+
+    ${lib.optionalString stdenv.isDarwin ''
+    # Install required library for ObjC interop.
+    # TODO: Is there no source code for this available?
+    cp -r ${CLTools_Executables}/usr/lib/arc $out/lib/arc
+    ''}
+  '';
+
+  preFixup = lib.optionalString stdenv.isLinux ''
+    # This is cheesy, but helps the patchelf hook remove /build from RPATH.
+    cd $NIX_BUILD_TOP
+    mv build buildx
+  '';
+
+  postFixup = lib.optionalString stdenv.isDarwin ''
+    # These libraries need to use the system install name. The official SDK
+    # does the same (as opposed to using rpath). Presumably, they are part of
+    # the stable ABI. Not using the system libraries at run-time is known to
+    # cause ObjC class conflicts and segfaults.
+    declare -A systemLibs=(
+      [libswiftCore.dylib]=1
+      [libswiftDarwin.dylib]=1
+      [libswiftSwiftOnoneSupport.dylib]=1
+      [libswift_Concurrency.dylib]=1
+    )
+
+    for systemLib in "''${!systemLibs[@]}"; do
+      install_name_tool -id /usr/lib/swift/$systemLib $lib/${swiftLibSubdir}/$systemLib
+    done
+
+    for file in $out/bin/swift-frontend $lib/${swiftLibSubdir}/*.dylib; do
+      changeArgs=""
+      for dylib in $(otool -L $file | awk '{ print $1 }'); do
+        if [[ ''${systemLibs["$(basename $dylib)"]} ]]; then
+          changeArgs+=" -change $dylib /usr/lib/swift/$(basename $dylib)"
+        elif [[ "$dylib" = */bootstrapping1/* ]]; then
+          changeArgs+=" -change $dylib $lib/lib/swift/$(basename $dylib)"
+        fi
+      done
+      if [[ -n "$changeArgs" ]]; then
+        install_name_tool $changeArgs $file
+      fi
+    done
+
+    wrapProgram $out/bin/swift-frontend \
+      --prefix PATH : ${lib.makeBinPath runtimeDeps}
+  '';
+
+  passthru = {
+    inherit
+      swiftOs swiftArch
+      swiftModuleSubdir swiftLibSubdir
+      swiftStaticModuleSubdir swiftStaticLibSubdir;
+
+    # Internal attr for the wrapper.
+    _wrapperParams = wrapperParams;
+  };
+
+  meta = {
+    description = "The Swift Programming Language";
+    homepage = "https://github.com/apple/swift";
+    maintainers = with lib.maintainers; [ dtzWill trepetti dduan trundle stephank ];
+    license = lib.licenses.asl20;
+    platforms = with lib.platforms; linux ++ darwin;
+    # Swift doesn't support 32-bit Linux, unknown on other platforms.
+    badPlatforms = lib.platforms.i686;
+    timeout = 86400; # 24 hours.
+  };
+}

pkgs/development/compilers/swift/compiler/patches/clang-wrap.patch

···
+Wrap the clang produced during the build
+
+--- a/tools/driver/CMakeLists.txt
++++ b/tools/driver/CMakeLists.txt
+@@ -59,6 +59,13 @@ endif()
+ 
+ add_dependencies(clang clang-resource-headers)
+ 
++# Nix: wrap the clang build.
++add_custom_command(
++  TARGET clang POST_BUILD
++  COMMAND nix-swift-make-clang-wrapper $<TARGET_FILE:clang>
++  VERBATIM
++)
++
+ if(NOT CLANG_LINKS_TO_CREATE)
+   set(CLANG_LINKS_TO_CREATE clang++ clang-cl clang-cpp)
+ endif()

pkgs/development/compilers/swift/compiler/patches/llvm-module-cache.patch

···
+The compiler fails if LLVM modules are enabled and it cannot write its module
+cache. This patch detects and rejects the fake, non-existant $HOME used in Nix
+builds.
+
+We could simply return false in `cache_directory`, but that completely disables
+module caching, and may unnecessarily slow down builds. Instead, let it use
+'/tmp/.cache'.
+
+--- a/lib/Support/Unix/Path.inc
++++ b/lib/Support/Unix/Path.inc
+@@ -1380,6 +1380,9 @@ bool user_config_directory(SmallVectorImpl<char> &result) {
+   if (!home_directory(result)) {
+     return false;
+   }
++  if (std::equal(result.begin(), result.end(), "/homeless-shelter")) {
++    return false;
++  }
+   append(result, ".config");
+   return true;
+ }
+@@ -1401,6 +1404,9 @@ bool cache_directory(SmallVectorImpl<char> &result) {
+   if (!home_directory(result)) {
+     return false;
+   }
++  if (std::equal(result.begin(), result.end(), "/homeless-shelter")) {
++    system_temp_directory(true/*ErasedOnReboot*/, result);
++  }
+   append(result, ".cache");
+   return true;
+ }

pkgs/development/compilers/swift/compiler/patches/swift-darwin-fix-bootstrap.patch

···
+This patch fixes dylib references during bootstrapping. It's possible
+`LIBSWIFT_BUILD_MODE=BOOTSTRAPPING` is not really well tested on Darwin,
+because official builds don't use it.
+
+In the near future, Swift will require an existing Swift toolchain to
+bootstrap, and we will likely have to replace this any way.
+
+--- a/stdlib/cmake/modules/AddSwiftStdlib.cmake
++++ b/stdlib/cmake/modules/AddSwiftStdlib.cmake
+@@ -1035,6 +1035,10 @@ function(add_swift_target_library_single target name)
+       set(install_name_dir "${SWIFTLIB_SINGLE_DARWIN_INSTALL_NAME_DIR}")
+     endif()
+ 
++    if(DEFINED SWIFTLIB_SINGLE_BOOTSTRAPPING)
++      set(install_name_dir "${lib_dir}/${output_sub_dir}")
++    endif()
++
+     set_target_properties("${target}"
+       PROPERTIES
+       INSTALL_NAME_DIR "${install_name_dir}")

pkgs/development/compilers/swift/compiler/patches/swift-darwin-plistbuddy-workaround.patch

···
+CMake tries to read a list field from SDKSettings.plist, but the output of
+facebook/xcbuild PlistBuddy is incompatible with Apple's.
+
+Simply set the supported architectures to the one target architecture we're
+building for.
+
+--- a/cmake/modules/SwiftConfigureSDK.cmake
++++ b/cmake/modules/SwiftConfigureSDK.cmake
+@@ -189,7 +189,7 @@ macro(configure_sdk_darwin
+   endif()
+ 
+   # Remove any architectures not supported by the SDK.
+-  remove_sdk_unsupported_archs(${name} ${xcrun_name} ${SWIFT_SDK_${prefix}_PATH} SWIFT_SDK_${prefix}_ARCHITECTURES)
++  set(SWIFT_SDK_${prefix}_ARCHITECTURES "@swiftArch@")
+ 
+   list_intersect(
+     "${SWIFT_DARWIN_MODULE_ARCHS}"            # lhs

pkgs/development/compilers/swift/compiler/patches/swift-linux-fix-linking.patch

···
+--- a/lib/Driver/ToolChains.cpp
++++ b/lib/Driver/ToolChains.cpp
+@@ -1475,7 +1475,17 @@ const char *ToolChain::getClangLinkerDriver(
+ 
+     // If there is a linker driver in the toolchain folder, use that instead.
+     if (auto tool = llvm::sys::findProgramByName(LinkerDriver, {toolchainPath}))
+-      LinkerDriver = Args.MakeArgString(tool.get());
++      return Args.MakeArgString(tool.get());
++  }
++
++  // For Nix, prefer linking using the wrapped system clang, instead of using
++  // the unwrapped clang packaged with swift. The latter is unable to link, but
++  // we still want to use it for other purposes (clang importer).
++  if (auto nixCC = llvm::sys::Process::GetEnv("NIX_CC")) {
++    llvm::SmallString<128> binDir(nixCC.getValue());
++    llvm::sys::path::append(binDir, "bin");
++    if (auto tool = llvm::sys::findProgramByName(LinkerDriver, {binDir.str()}))
++      return Args.MakeArgString(tool.get());
+   }
+ 
+   return LinkerDriver;

pkgs/development/compilers/swift/compiler/patches/swift-nix-resource-root.patch

···
+Swift normally looks for the Clang resource dir in a subdir/symlink of its own
+resource dir. We provide a symlink to the Swift build-time Clang as a default
+there, but we also here patch two checks to try locate it via NIX_CC.
+
+The first (ClangImporter.cpp) happens when Swift code imports C modules. The
+second (ToolChains.cpp) happens when Swift is used to link the final product.
+
+--- a/lib/ClangImporter/ClangImporter.cpp
++++ b/lib/ClangImporter/ClangImporter.cpp
+@@ -68,6 +68,7 @@
+ #include "llvm/Support/FileSystem.h"
+ #include "llvm/Support/Memory.h"
+ #include "llvm/Support/Path.h"
++#include "llvm/Support/Process.h"
+ #include "llvm/Support/YAMLParser.h"
+ #include "llvm/Support/YAMLTraits.h"
+ #include <algorithm>
+@@ -809,6 +810,17 @@ importer::addCommonInvocationArguments(
+ 
+   const std::string &overrideResourceDir = importerOpts.OverrideResourceDir;
+   if (overrideResourceDir.empty()) {
++    // Prefer the Clang resource directory from NIX_CC, to allow swapping in a
++    // different stdenv.
++    // TODO: Figure out how to provide a user override for this. Probably a
++    // niche use case, though, and for now a user can unset NIX_CC to work
++    // around it if necessary.
++    if (auto nixCC = llvm::sys::Process::GetEnv("NIX_CC")) {
++      llvm::SmallString<128> resourceDir(nixCC.getValue());
++      llvm::sys::path::append(resourceDir, "resource-root");
++      invocationArgStrs.push_back("-resource-dir");
++      invocationArgStrs.push_back(std::string(resourceDir.str()));
++    } else {
+     llvm::SmallString<128> resourceDir(searchPathOpts.RuntimeResourcePath);
+ 
+     // Adjust the path to refer to our copy of the Clang resource directory
+@@ -824,6 +836,7 @@ importer::addCommonInvocationArguments(
+     // Set the Clang resource directory to the path we computed.
+     invocationArgStrs.push_back("-resource-dir");
+     invocationArgStrs.push_back(std::string(resourceDir.str()));
++    } // nixCC
+   } else {
+     invocationArgStrs.push_back("-resource-dir");
+     invocationArgStrs.push_back(overrideResourceDir);
+--- a/lib/Driver/ToolChains.cpp
++++ b/lib/Driver/ToolChains.cpp
+@@ -1372,10 +1372,20 @@ void ToolChain::getClangLibraryPath(const ArgList &Args,
+                                     SmallString<128> &LibPath) const {
+   const llvm::Triple &T = getTriple();
+ 
++  // Nix: We provide a `clang` symlink in the default Swift resource root, but
++  // prefer detecting the Clang resource root via NIX_CC, to allow swapping in
++  // a different stdenv. However, always honor a user-provided `-resource-dir`.
++  auto nixCC = llvm::sys::Process::GetEnv("NIX_CC");
++  if (nixCC && !Args.hasArgNoClaim(options::OPT_resource_dir)) {
++    LibPath.assign(nixCC.getValue());
++    llvm::sys::path::append(LibPath, "resource-root");
++  } else {
+   getResourceDirPath(LibPath, Args, /*Shared=*/true);
+   // Remove platform name.
+   llvm::sys::path::remove_filename(LibPath);
+-  llvm::sys::path::append(LibPath, "clang", "lib",
++  llvm::sys::path::append(LibPath, "clang");
++  } // nixCC
++  llvm::sys::path::append(LibPath, "lib",
+                           T.isOSDarwin() ? "darwin"
+                                          : getPlatformNameForTriple(T));
+ }

pkgs/development/compilers/swift/compiler/patches/swift-prevent-sdk-dirs-warning.patch

···
+Prevents a user-visible warning on every compilation:
+
+  ld: warning: directory not found for option '-L.../MacOSX11.0.sdk/usr/lib/swift'
+
+--- a/lib/Driver/ToolChains.cpp
++++ b/lib/Driver/ToolChains.cpp
+@@ -1455,9 +1455,11 @@ void ToolChain::getRuntimeLibraryPaths(SmallVectorImpl<std::string> &runtimeLibP
+       runtimeLibPaths.push_back(std::string(scratchPath.str()));
+     }
+ 
++    if (!SDKPath.startswith("@storeDir@")) {
+     scratchPath = SDKPath;
+     llvm::sys::path::append(scratchPath, "usr", "lib", "swift");
+     runtimeLibPaths.push_back(std::string(scratchPath.str()));
++    }
+   }
+ }
+ 
+--- a/lib/Frontend/CompilerInvocation.cpp
++++ b/lib/Frontend/CompilerInvocation.cpp
+@@ -185,7 +185,9 @@ static void updateRuntimeLibraryPaths(SearchPathOptions &SearchPathOpts,
+       RuntimeLibraryImportPaths.push_back(std::string(LibPath.str()));
+     }
+ 
+-    LibPath = SearchPathOpts.getSDKPath();
++    auto SDKPath = SearchPathOpts.getSDKPath();
++    if (!SDKPath.startswith("@storeDir@")) {
++    LibPath = SDKPath;
+     llvm::sys::path::append(LibPath, "usr", "lib", "swift");
+     if (!Triple.isOSDarwin()) {
+       // Use the non-architecture suffixed form with directory-layout
+@@ -200,6 +202,7 @@ static void updateRuntimeLibraryPaths(SearchPathOptions &SearchPathOpts,
+       llvm::sys::path::append(LibPath, swift::getMajorArchitectureName(Triple));
+     }
+     RuntimeLibraryImportPaths.push_back(std::string(LibPath.str()));
++    }
+   }
+   SearchPathOpts.setRuntimeLibraryImportPaths(RuntimeLibraryImportPaths);
+ }

pkgs/development/compilers/swift/compiler/patches/swift-separate-lib.patch

···
+Patch paths to use the separate 'lib' output. One of the things this patch
+fixes is the output of `swift -frontend -print-target-info`, which swiftpm uses
+to set rpath on Linux.
+
+The check if the executable path starts with 'out' is necessary for
+bootstrapping, or the compiler will fail when run from the build directory.
+
+--- a/lib/Frontend/CompilerInvocation.cpp
++++ b/lib/Frontend/CompilerInvocation.cpp
+@@ -49,11 +49,16 @@ swift::CompilerInvocation::CompilerInvocation() {
+ void CompilerInvocation::computeRuntimeResourcePathFromExecutablePath(
+     StringRef mainExecutablePath, bool shared,
+     llvm::SmallVectorImpl<char> &runtimeResourcePath) {
++  if (mainExecutablePath.startswith("@storeDir@")) {
++    auto libPath = StringRef("@lib@");
++    runtimeResourcePath.append(libPath.begin(), libPath.end());
++  } else {
+   runtimeResourcePath.append(mainExecutablePath.begin(),
+                              mainExecutablePath.end());
+ 
+   llvm::sys::path::remove_filename(runtimeResourcePath); // Remove /swift
+   llvm::sys::path::remove_filename(runtimeResourcePath); // Remove /bin
++  }
+   appendSwiftLibDir(runtimeResourcePath, shared);
+ }
+ 

pkgs/development/compilers/swift/compiler/patches/swift-wrap.patch

···
+Wrap the swift compiler produced during the build
+
+--- a/tools/driver/CMakeLists.txt
++++ b/tools/driver/CMakeLists.txt
+@@ -16,6 +16,13 @@ if(${LIBSWIFT_BUILD_MODE} MATCHES "BOOTSTRAPPING.*")
+                           swiftDriverTool
+                           libswiftStub)
+ 
++  # Nix: wrap the swift build.
++  add_custom_command(
++    TARGET swift-frontend-bootstrapping0 POST_BUILD
++    COMMAND nix-swift-make-swift-wrapper $<TARGET_FILE:swift-frontend-bootstrapping0>
++    VERBATIM
++  )
++
+   swift_create_post_build_symlink(swift-frontend-bootstrapping0
+     SOURCE "swift-frontend${CMAKE_EXECUTABLE_SUFFIX}"
+     DESTINATION "swiftc${CMAKE_EXECUTABLE_SUFFIX}"
+@@ -34,6 +41,13 @@ if(${LIBSWIFT_BUILD_MODE} MATCHES "BOOTSTRAPPING.*")
+                           swiftDriverTool
+                           libswift-bootstrapping1)
+ 
++  # Nix: wrap the swift build.
++  add_custom_command(
++    TARGET swift-frontend-bootstrapping1 POST_BUILD
++    COMMAND nix-swift-make-swift-wrapper $<TARGET_FILE:swift-frontend-bootstrapping1>
++    VERBATIM
++  )
++
+   swift_create_post_build_symlink(swift-frontend-bootstrapping1
+     SOURCE "swift-frontend${CMAKE_EXECUTABLE_SUFFIX}"
+     DESTINATION "swiftc${CMAKE_EXECUTABLE_SUFFIX}"
+@@ -50,6 +64,13 @@ target_link_libraries(swift-frontend
+                         swiftDriverTool
+                         libswift)
+ 
++# Nix: wrap the swift build.
++add_custom_command(
++  TARGET swift-frontend POST_BUILD
++  COMMAND nix-swift-make-swift-wrapper $<TARGET_FILE:swift-frontend>
++  VERBATIM
++)
++
+ # Create a `swift-driver` executable adjacent to the `swift-frontend` executable
+ # to ensure that `swiftc` forwards to the standalone driver when invoked.
+ swift_create_early_driver_copies(swift-frontend)

pkgs/development/compilers/swift/default.nix

···
-{ lib, stdenv
-, cmake
-, coreutils
-, glibc
-, gccForLibs
-, which
-, perl
-, libedit
-, ninja
-, pkg-config
-, sqlite
-, libxml2
-, clang_13
-, python3
-, ncurses
-, libuuid
-, libxcrypt
-, icu
-, libgcc
-, libblocksruntime
-, curl
-, rsync
-, git
-, libgit2
-, fetchFromGitHub
-, makeWrapper
-, gnumake
-, file
+{ lib
+, pkgs
+, newScope
+, darwin
+, llvmPackages_latest
+, overrideCC
 }:
 
 let
-  # The Swift toolchain script builds projects with separate repos. By convention, some of them share
-  # the same version with the main Swift compiler project per release. We fetch these with
-  # `fetchSwiftRelease`. The rest have their own versions locked to each Swift release, as defined in the
-  # Swift compiler repo:
-  #   utils/update_checkout/update_checkout-config.json.
-  #
-  # ... among projects listed in that file, we provide our own:
-  # - CMake
-  # - ninja
-  # - icu
-  #
-  # ... we'd like to include the following in the future:
-  # - stress-tester
-  # - integration-tests
-
-  versions = {
-    swift = "5.6.2";
-    yams = "4.0.2";
-    argumentParser = "1.0.3";
-    format = "release/5.6";
-    crypto = "1.1.5";
-    nio = "2.31.2";
-    nio-ssl = "2.15.0";
-  };
+  self = rec {
 
-  fetchAppleRepo = { repo, rev, sha256 }:
-    fetchFromGitHub {
-      owner = "apple";
-      inherit repo rev sha256;
-      name = "${repo}-${rev}-src";
-    };
+    callPackage = newScope self;
 
-  fetchSwiftRelease = { repo, sha256, fetchSubmodules ? false }:
-    fetchFromGitHub {
-      owner = "apple";
-      inherit repo sha256 fetchSubmodules;
-      rev = "swift-${versions.swift}-RELEASE";
-      name = "${repo}-${versions.swift}-src";
-    };
+    # Current versions of Swift on Darwin require macOS SDK 10.15 at least.
+    # Re-export this so we can rely on the minimum Swift SDK elsewhere.
+    apple_sdk = pkgs.darwin.apple_sdk_11_0;
 
-  sources = {
-    # Projects that share `versions.swift` for each release.
+    # Our current Clang on Darwin is v11, but we need at least v12. The
+    # following applies the newer Clang with the same libc overrides as
+    # `apple_sdk.stdenv`.
+    #
+    # If 'latest' becomes an issue, recommend replacing it with v14, which is
+    # currently closest to the official Swift builds.
+    clang = if pkgs.stdenv.isDarwin
+      then
+        llvmPackages_latest.clang.override rec {
+          libc = apple_sdk.Libsystem;
+          bintools = pkgs.bintools.override { inherit libc; };
+        }
+      else
+        llvmPackages_latest.clang;
 
-    swift = fetchSwiftRelease {
-      repo = "swift";
-      sha256 = "sha256-wiRXAXWEksJuy+YQQ+B7tzr2iLkSVkgV6o+wIz7yKJA=";
-    };
-    cmark = fetchSwiftRelease {
-      repo = "swift-cmark";
-      sha256 = "sha256-f0BoTs4HYdx/aJ9HIGCWMalhl8PvClWD6R4QK3qSgAw=";
-    };
-    llbuild = fetchSwiftRelease {
-      repo = "swift-llbuild";
-      sha256 = "sha256-SQ6V0zVshIYMjayx+ZpYuLijgQ89tqRnPlXBPf2FYqM=";
+    # Overrides that create a useful environment for swift packages, allowing
+    # packaging with `swiftPackages.callPackage`. These are similar to
+    # `apple_sdk_11_0.callPackage`, with our clang on top.
+    inherit (clang) bintools;
+    stdenv = overrideCC pkgs.stdenv clang;
+    darwin = pkgs.darwin.overrideScope (_: prev: {
+      inherit apple_sdk;
+      inherit (apple_sdk) Libsystem LibsystemCross libcharset libunwind objc4 configd IOKit Security;
+      CF = apple_sdk.CoreFoundation;
+    });
+    xcodebuild = pkgs.xcbuild.override {
+      inherit (apple_sdk.frameworks) CoreServices CoreGraphics ImageIO;
+      inherit stdenv;
+      sdkVer = "10.15";
     };
-    driver = fetchSwiftRelease {
-      repo = "swift-driver";
-      sha256 = "sha256-D5/C4Rbv5KIsKpy6YbuMxGIGaQkn80PD4Cp0l6bPKzY=";
-    };
-    toolsSupportCore = fetchSwiftRelease {
-      repo = "swift-tools-support-core";
-      sha256 = "sha256-FbtQCq1sSlzrskCrgzD4iYuo5eGaXrAUUxoNX/BiOfg=";
-    };
-    swiftpm = fetchSwiftRelease {
-      repo = "swift-package-manager";
-      sha256 = "sha256-esO4Swz3UYngbVgxoV+fkhSC0AU3IaxVjWkgK/s3x68=";
-    };
-    syntax = fetchSwiftRelease {
-      repo = "swift-syntax";
-      sha256 = "sha256-C9FPCtq49BvKXtTWWeReYWNrU70pHzT2DhAv3NiTbPU=";
-    };
-    corelibsXctest = fetchSwiftRelease {
-      repo = "swift-corelibs-xctest";
-      sha256 = "sha256-0hizfnKJaUUA+jXuXzXWk72FmlSyc+UGEf7BTLdJrx4=";
-    };
-    corelibsFoundation = fetchSwiftRelease {
-      repo = "swift-corelibs-foundation";
-      sha256 = "sha256-8sCL8Ia6yb6bRsJZ52gUJH0jN3lwClM573G8jgUdEhw=";
-    };
-    corelibsLibdispatch = fetchSwiftRelease {
-      repo = "swift-corelibs-libdispatch";
-      sha256 = "sha256-1tIskUMnfblnvZaFDQPUMBfWTmBYG98s7rEww7PwZO8=";
-      fetchSubmodules = true;
-    };
-    indexstoreDb = fetchSwiftRelease {
-      repo = "indexstore-db";
-      sha256 = "sha256-/PO4eMiASZN3pjFjBQ1r8vYwGRn6xm3SWaB2HDZlkPs=";
-    };
-    sourcekitLsp = fetchSwiftRelease {
-      repo = "sourcekit-lsp";
-      sha256 = "sha256-ttgUC4ZHD3P/xLHllEbACtHVrJ6HXqeVWccXcoPMkts=";
-    };
-    llvmProject = fetchSwiftRelease {
-      repo = "llvm-project";
-      sha256 = "sha256-YVs3lKV2RlaovpYkdGO+vzypolrmXmbKBBP4+osNMYw=";
-    };
-    docc = fetchSwiftRelease {
-      repo = "swift-docc";
-      sha256 = "sha256-rWiaNamZoHTO1bKpubxuT7m1IBOl7amT5M71mNauilY=";
-    };
-    docc-render-artifact = fetchSwiftRelease {
-      repo = "swift-docc-render-artifact";
-      sha256 = "sha256-AX+rtDLhq8drk7N6/hoH3fQioudmmTCnEhR45bME8uU=";
-    };
-    docc-symbolkit = fetchSwiftRelease {
-      repo = "swift-docc-symbolkit";
-      sha256 = "sha256-Xy1TQ5ucDW+MnkeOvVznsATBmwcQ3p1x+ofQ22ofk+o=";
-    };
-    lmdb = fetchSwiftRelease {
-      repo = "swift-lmdb";
-      sha256 = "sha256-i2GkWRWq1W5j8rF4PiHwWgT4Dur5FCY2o44HvUU3vtQ=";
-    };
-    markdown = fetchSwiftRelease {
-      repo = "swift-markdown";
-      sha256 = "sha256-XtFSBiNHhmULjS4OqSpMgUetLu3peRg7l6HpjwVsTj8=";
+    xcbuild = xcodebuild;
+
+    swift-unwrapped = callPackage ./compiler {
+      inherit (darwin) DarwinTools cctools sigtool;
+      inherit (apple_sdk) CLTools_Executables;
+      inherit (apple_sdk.frameworks) CoreServices Foundation Combine;
     };
 
-    cmark-gfm = fetchAppleRepo {
-      repo = "swift-cmark";
-      rev = "swift-${versions.swift}-RELEASE-gfm";
-      sha256 = "sha256-g28iKmMR2W0r1urf8Fk1HBxAp5OlonNYSVN3Ril66tQ=";
+    swift = callPackage ./wrapper {
+      swift = swift-unwrapped;
     };
 
-    # Projects that have their own versions during each release
-
-    argumentParser = fetchAppleRepo {
-      repo = "swift-argument-parser";
-      rev = "${versions.argumentParser}";
-      sha256 = "sha256-vNqkuAwSZNCWvwe6E5BqbXQdIbmIia0dENmmSQ9P8Mo=";
-    };
-    format = fetchAppleRepo {
-      repo = "swift-format";
-      rev = "${versions.format}";
-      sha256 = "sha256-1f5sIrv9IbPB7Vnahq1VwH8gT41dcjWldRwvVEaMdto=";
-    };
-    crypto = fetchAppleRepo {
-      repo = "swift-crypto";
-      rev = "${versions.crypto}";
-      sha256 = "sha256-jwxXQuOF+CnpLMwTZ2z52Fgx2b97yWzXiPTx0Ye8KCQ=";
-    };
-    nio = fetchAppleRepo {
-      repo = "swift-nio";
-      rev = versions.nio;
-      sha256 = "sha256-FscOA/S7on31QCR/MZFjg4ZB3FGJ+rdptZ6MRZJXexE=";
-    };
-    nio-ssl = fetchAppleRepo {
-      repo = "swift-nio-ssl";
-      rev = versions.nio-ssl;
-      sha256 = "sha256-5QGkmkCOXhG3uOdf0bd3Fo1MFekB8/WcveBXGhtVZKo=";
-    };
-    yams = fetchFromGitHub {
-      owner = "jpsim";
-      repo = "Yams";
-      rev = versions.yams;
-      sha256 = "sha256-cTkCAwxxLc35laOon1ZXXV8eAxX02oDolJyPauhZado=";
-      name = "Yams-${versions.yams}-src";
-    };
   };
 
-  devInputs = [
-    curl
-    glibc
-    icu
-    libblocksruntime
-    libedit
-    libgcc
-    libuuid
-    libxcrypt
-    libxml2
-    ncurses
-    sqlite
-  ];
-
-  python = (python3.withPackages (ps: [ps.six]));
-
-  cmakeFlags = [
-    "-DGLIBC_INCLUDE_PATH=${stdenv.cc.libc.dev}/include"
-    "-DC_INCLUDE_DIRS=${lib.makeSearchPathOutput "dev" "include" devInputs}:${libxml2.dev}/include/libxml2"
-    "-DGCC_INSTALL_PREFIX=${gccForLibs}"
-  ];
-
-in
-stdenv.mkDerivation {
-  pname = "swift";
-  version = versions.swift;
-
-  nativeBuildInputs = [
-    cmake
-    git
-    makeWrapper
-    ninja
-    perl
-    pkg-config
-    python
-    rsync
-    which
-  ];
-  buildInputs = devInputs ++ [
-    clang_13
-  ];
-
-  # TODO: Revisit what needs to be propagated and how.
-  propagatedBuildInputs = [
-    libgcc
-    libgit2
-    python
-  ];
-  propagatedUserEnvPkgs = [ git pkg-config ];
-
-  hardeningDisable = [ "format" ]; # for LLDB
-
-  unpackPhase = ''
-    mkdir src
-    cd src
-    export SWIFT_SOURCE_ROOT=$PWD
-
-    cp -r ${sources.swift} swift
-    cp -r ${sources.cmark} cmark
-    cp -r ${sources.llbuild} llbuild
-    cp -r ${sources.argumentParser} swift-argument-parser
-    cp -r ${sources.driver} swift-driver
-    cp -r ${sources.toolsSupportCore} swift-tools-support-core
-    cp -r ${sources.swiftpm} swiftpm
-    cp -r ${sources.syntax} swift-syntax
-    cp -r ${sources.corelibsXctest} swift-corelibs-xctest
-    cp -r ${sources.corelibsFoundation} swift-corelibs-foundation
-    cp -r ${sources.corelibsLibdispatch} swift-corelibs-libdispatch
-    cp -r ${sources.yams} yams
-    cp -r ${sources.indexstoreDb} indexstore-db
-    cp -r ${sources.sourcekitLsp} sourcekit-lsp
-    cp -r ${sources.format} swift-format
-    cp -r ${sources.crypto} swift-crypto
-    cp -r ${sources.llvmProject} llvm-project
-    cp -r ${sources.cmark-gfm} swift-cmark-gfm
-    cp -r ${sources.docc} swift-docc
-    cp -r ${sources.docc-render-artifact} swift-docc-render-artifact
-    cp -r ${sources.docc-symbolkit} swift-docc-symbolkit
-    cp -r ${sources.lmdb} swift-lmdb
-    cp -r ${sources.markdown} swift-markdown
-    cp -r ${sources.nio} swift-nio
-    cp -r ${sources.nio-ssl} swift-nio-ssl
-
-    chmod -R u+w .
-  '';
-
-  patchPhase = ''
-    # Just patch all the things for now, we can focus this later.
-    patchShebangs $SWIFT_SOURCE_ROOT
-
-    # TODO: eliminate use of env.
-    find -type f -print0 | xargs -0 sed -i \
-      -e 's|/usr/bin/env|${coreutils}/bin/env|g' \
-      -e 's|/usr/bin/make|${gnumake}/bin/make|g' \
-      -e 's|/bin/mkdir|${coreutils}/bin/mkdir|g' \
-      -e 's|/bin/cp|${coreutils}/bin/cp|g' \
-      -e 's|/usr/bin/file|${file}/bin/file|g'
-
-    # Build configuration patches.
-    patch -p1 -d swift -i ${./patches/0001-build-presets-linux-don-t-require-using-Ninja.patch}
-    patch -p1 -d swift -i ${./patches/0002-build-presets-linux-allow-custom-install-prefix.patch}
-    patch -p1 -d swift -i ${./patches/0003-build-presets-linux-don-t-build-extra-libs.patch}
-    patch -p1 -d swift -i ${./patches/0004-build-presets-linux-plumb-extra-cmake-options.patch}
-    patch -p1 -d swift -i ${./patches/0007-build-presets-linux-os-stdlib.patch}
-    substituteInPlace swift/cmake/modules/SwiftConfigureSDK.cmake \
-      --replace '/usr/include' "${stdenv.cc.libc.dev}/include"
-    sed -i swift/utils/build-presets.ini \
-      -e 's/^test-installable-package$/# \0/' \
-      -e 's/^test$/# \0/' \
-      -e 's/^validation-test$/# \0/' \
-      -e 's/^long-test$/# \0/' \
-      -e 's/^stress-test$/# \0/' \
-      -e 's/^test-optimized$/# \0/' \
-      -e 's/^swift-install-components=autolink.*$/\0;editor-integration/'
-
-    # LLVM toolchain patches.
-    patch -p1 -d llvm-project/clang -i ${./patches/0005-clang-toolchain-dir.patch}
-    patch -p1 -d llvm-project/clang -i ${./patches/0006-clang-purity.patch}
-    substituteInPlace llvm-project/clang/lib/Driver/ToolChains/Linux.cpp \
-      --replace 'SysRoot + "/lib' '"${glibc}/lib" "' \
-      --replace 'SysRoot + "/usr/lib' '"${glibc}/lib" "' \
-      --replace 'LibDir = "lib";' 'LibDir = "${glibc}/lib";' \
-      --replace 'LibDir = "lib64";' 'LibDir = "${glibc}/lib";' \
-      --replace 'LibDir = X32 ? "libx32" : "lib64";' 'LibDir = "${glibc}/lib";'
-
-    # Substitute ncurses for curses in llbuild.
-    sed -i 's/curses/ncurses/' llbuild/*/*/CMakeLists.txt
-    sed -i 's/curses/ncurses/' llbuild/*/*/*/CMakeLists.txt
-
-    # uuid.h is not part of glibc, but of libuuid.
-    sed -i 's|''${GLIBC_INCLUDE_PATH}/uuid/uuid.h|${libuuid.dev}/include/uuid/uuid.h|' swift/stdlib/public/Platform/glibc.modulemap.gyb
-
-    # Support library build script patches.
-    PREFIX=''${out/#\/}
-    substituteInPlace swift/utils/swift_build_support/swift_build_support/products/benchmarks.py \
-      --replace \
-      "'--toolchain', toolchain_path," \
-      "'--toolchain', '/build/install/$PREFIX',"
-    substituteInPlace swift/benchmark/scripts/build_script_helper.py \
-      --replace \
-      "swiftbuild_path = os.path.join(args.toolchain, \"usr\", \"bin\", \"swift-build\")" \
-      "swiftbuild_path = os.path.join(args.toolchain, \"bin\", \"swift-build\")"
-    substituteInPlace swift-corelibs-xctest/build_script.py \
-      --replace usr "$PREFIX"
-
-    # Can be removed in later swift-docc versions, see
-    # https://github.com/apple/swift-docc/commit/bff70b847008f91ac729cfd299a85481eef3f581
-    substituteInPlace swift-docc/build-script-helper.py \
-      --replace \
-      "subprocess.check_output(cmd, env=env).strip(), 'docc')" \
-      "subprocess.check_output(cmd, env=env).strip().decode(), 'docc')"
-
-    # Can be removed in later Swift versions, see
-    # https://github.com/apple/swift/pull/58755
-    substituteInPlace swift/utils/process-stats-dir.py \
-      --replace \
-      "type=argparse.FileType('wb', 0)," \
-      "type=argparse.FileType('w', 0),"
-
-    # Apply Python 3 fix, see
-    # https://github.com/apple/swift/commit/ec6bc595092974628b27b114a472e84162261bbd
-    substituteInPlace swift/utils/swift_build_support/swift_build_support/productpipeline_list_builder.py \
-      --replace \
-      "filter(lambda x: x is not None, pipeline)" \
-      "[p for p in pipeline if p is not None]"
-  '';
-
-  configurePhase = ''
-    cd ..
-
-    mkdir build install
-    export SWIFT_BUILD_ROOT=$PWD/build
-    export SWIFT_INSTALL_DIR=$PWD/install
-
-    export INSTALLABLE_PACKAGE=$PWD/swift.tar.gz
-    export NIX_ENFORCE_PURITY=
-
-    cd $SWIFT_BUILD_ROOT
-  '';
-
-  buildPhase = ''
-    # Explicitly include C++ headers to prevent errors where stdlib.h is not found from cstdlib.
-    export NIX_CFLAGS_COMPILE="$(< ${clang_13}/nix-support/libcxx-cxxflags) $NIX_CFLAGS_COMPILE"
-
-    # During the Swift build, a full local LLVM build is performed and the resulting clang is
-    # invoked. This compiler is not using the Nix wrappers, so it needs some help to find things.
-    export NIX_LDFLAGS_BEFORE="-rpath ${gccForLibs.lib}/lib -L${gccForLibs.lib}/lib $NIX_LDFLAGS_BEFORE"
-
-    # However, we want to use the wrapped compiler whenever possible.
-    export CC="${clang_13}/bin/clang"
-
-    $SWIFT_SOURCE_ROOT/swift/utils/build-script \
-      --preset=buildbot_linux \
-      installable_package=$INSTALLABLE_PACKAGE \
-      install_prefix=$out \
-      install_destdir=$SWIFT_INSTALL_DIR \
-      extra_cmake_options="${lib.concatStringsSep "," cmakeFlags}"
-  '';
-
-  doCheck = true;
-
-  checkInputs = [ file ];
-
-  checkPhase = ''
-    # Remove compiler build system tests which fail due to our modified default build profile and
-    # nixpkgs-provided version of CMake.
-    rm $SWIFT_SOURCE_ROOT/swift/validation-test/BuildSystem/infer_implies_install_all.test
-    rm $SWIFT_SOURCE_ROOT/swift/validation-test/BuildSystem/infer_dumps_deps_if_verbose_build.test
-
-    # This test apparently requires Python 2 (strings are assumed to be bytes-like), but the build
-    # process overall now otherwise requires Python 3 (which is what we have updated to). A fix PR
-    # has been submitted upstream.
-    rm $SWIFT_SOURCE_ROOT/swift/validation-test/SIL/verify_all_overlays.py
-
-    # TODO: consider fixing and re-adding. This test fails due to a non-standard "install_prefix".
-    rm $SWIFT_SOURCE_ROOT/swift/validation-test/Python/build_swift.swift
-
-    # We cannot handle the SDK location being in "Weird Location" due to Nix isolation.
-    rm $SWIFT_SOURCE_ROOT/swift/test/DebugInfo/compiler-flags.swift
-
-    # TODO: Fix issue with ld.gold invoked from script finding crtbeginS.o and crtendS.o.
-    rm $SWIFT_SOURCE_ROOT/swift/test/IRGen/ELF-remove-autolink-section.swift
-
-    # The following two tests fail because we use don't use the bundled libicu:
-    # [SOURCE_DIR/utils/build-script] ERROR: can't find source directory for libicu (tried /build/src/icu)
-    rm $SWIFT_SOURCE_ROOT/swift/validation-test/BuildSystem/default_build_still_performs_epilogue_opts_after_split.test
-    rm $SWIFT_SOURCE_ROOT/swift/validation-test/BuildSystem/test_early_swift_driver_and_infer.swift
-
-    # TODO: This test fails for some unknown reason
-    rm $SWIFT_SOURCE_ROOT/swift/test/Serialization/restrict-swiftmodule-to-revision.swift
-
-    # This test was flaky in ofborg, see #186476
-    rm $SWIFT_SOURCE_ROOT/swift/test/AutoDiff/compiler_crashers_fixed/sr14290-missing-debug-scopes-in-pullback-trampoline.swift
-
-    # TODO: consider using stress-tester and integration-test.
-
-    # Match the wrapped version of Swift to be installed.
-    export LIBRARY_PATH=${lib.makeLibraryPath [icu libgcc libuuid]}:$l
-
-    checkTarget=check-swift-all-${stdenv.hostPlatform.parsed.kernel.name}-${stdenv.hostPlatform.parsed.cpu.name}
-    ninjaFlags='-C buildbot_linux/swift-${stdenv.hostPlatform.parsed.kernel.name}-${stdenv.hostPlatform.parsed.cpu.name}'
-    ninjaCheckPhase
-  '';
-
-  installPhase = ''
-    mkdir -p $out
-
-    # Extract the generated tarball into the store.
-    tar xf $INSTALLABLE_PACKAGE -C $out --strip-components=3 ''${out/#\/}
-    find $out -type d -empty -delete
-
-    # Fix installation weirdness, also present in Apple’s official tarballs.
-    mv $out/local/include/indexstore $out/include
-    rmdir $out/local/include $out/local
-    rm -r $out/bin/sdk-module-lists $out/bin/swift-api-checker.py
-
-    wrapProgram $out/bin/swift \
-      --set CC $out/bin/clang \
-      --suffix C_INCLUDE_PATH : $out/lib/swift/clang/include \
-      --suffix CPLUS_INCLUDE_PATH : $out/lib/swift/clang/include \
-      --suffix LIBRARY_PATH : ${lib.makeLibraryPath [icu libgcc libuuid]} \
-      --suffix PATH : ${lib.makeBinPath [ stdenv.cc.bintools ]}
-
-    wrapProgram $out/bin/swiftc \
-      --set CC $out/bin/clang \
-      --suffix C_INCLUDE_PATH : $out/lib/swift/clang/include \
-      --suffix CPLUS_INCLUDE_PATH : $out/lib/swift/clang/include \
-      --suffix LIBRARY_PATH : ${lib.makeLibraryPath [icu libgcc libuuid]} \
-      --suffix PATH : ${lib.makeBinPath [ stdenv.cc.bintools ]}
-  '';
-
-  # Hack to avoid build and install directories in RPATHs.
-  preFixup = "rm -rf $SWIFT_BUILD_ROOT $SWIFT_INSTALL_DIR";
-
-  meta = with lib; {
-    description = "The Swift Programming Language";
-    homepage = "https://github.com/apple/swift";
-    maintainers = with maintainers; [ dtzWill trepetti dduan trundle ];
-    license = licenses.asl20;
-    # Swift doesn't support 32-bit Linux, unknown on other platforms.
-    platforms = platforms.linux;
-    badPlatforms = platforms.i686;
-    timeout = 86400; # 24 hours.
-  };
-}
+in self

pkgs/development/compilers/swift/patches/0001-build-presets-linux-don-t-require-using-Ninja.patch

···
-Don't build Ninja, we use our own.
-
---- a/utils/build-presets.ini
-+++ b/utils/build-presets.ini
-@@ -779,7 +779,7 @@ swiftpm
-
- dash-dash
-
--build-ninja
-+# build-ninja
- install-llvm
- install-swift
- install-lldb

pkgs/development/compilers/swift/patches/0002-build-presets-linux-allow-custom-install-prefix.patch

···
-Use custom install prefix.
-
---- a/utils/build-presets.ini
-+++ b/utils/build-presets.ini
-@@ -788,7 +788,7 @@
- install-swiftpm
- install-xctest
- install-libicu
--install-prefix=/usr
-+install-prefix=%(install_prefix)s
- install-libcxx
- install-sourcekit-lsp
- build-swift-static-stdlib

pkgs/development/compilers/swift/patches/0003-build-presets-linux-don-t-build-extra-libs.patch

···
-Disable targets, where we use Nix packages.
-
---- a/utils/build-presets.ini
-+++ b/utils/build-presets.ini
-@@ -818,8 +818,6 @@
- swiftpm
- swift-driver
- xctest
--libicu
--libcxx
- swiftdocc
- 
- # build-ninja
-@@ -830,9 +828,7 @@
- install-swiftpm
- install-swift-driver
- install-xctest
--install-libicu
- install-prefix=%(install_prefix)s
--install-libcxx
- install-sourcekit-lsp
- install-swiftdocc
- build-swift-static-stdlib

pkgs/development/compilers/swift/patches/0004-build-presets-linux-plumb-extra-cmake-options.patch

···
-Plumb extra-cmake-options.
-
---- a/utils/build-presets.ini
-+++ b/utils/build-presets.ini
-@@ -812,6 +812,8 @@
- # Path to the .tar.gz package we would create.
- installable-package=%(installable_package)s
-
-+extra-cmake-options=%(extra_cmake_options)s
-+
- [preset: buildbot_linux]
- mixin-preset=mixin_linux_installation
- build-subdir=buildbot_linux

pkgs/development/compilers/swift/patches/0006-clang-purity.patch

···
-Apply the "purity" patch (updated for 5.4.2).
-
---- a/lib/Driver/ToolChains/Gnu.cpp
-+++ b/lib/Driver/ToolChains/Gnu.cpp
-@@ -488,11 +488,5 @@
-     if (Args.hasArg(options::OPT_rdynamic))
-       CmdArgs.push_back("-export-dynamic");
--
--    if (!Args.hasArg(options::OPT_shared) && !IsStaticPIE) {
--      CmdArgs.push_back("-dynamic-linker");
--      CmdArgs.push_back(Args.MakeArgString(Twine(D.DyldPrefix) +
--                                           ToolChain.getDynamicLinker(Args)));
--    }
-   }
-
-   CmdArgs.push_back("-o");

pkgs/development/compilers/swift/patches/0007-build-presets-linux-os-stdlib.patch

···
-Use os-stdlib in tests.
-
---- a/utils/build-presets.ini
-+++ b/utils/build-presets.ini
-@@ -872,7 +872,7 @@
- indexstore-db
- sourcekit-lsp
- swiftdocc
--lit-args=-v --time-tests
-+lit-args=-v --time-tests --param use_os_stdlib
- 
- # rdar://problem/31454823
- lldb-test-swift-only

pkgs/development/compilers/swift/wrapper/default.nix

···
+{ stdenv
+, swift
+, wrapperParams ? swift._wrapperParams
+}:
+
+stdenv.mkDerivation (wrapperParams // {
+  pname = "swift-wrapper";
+  inherit (swift) version meta;
+
+  outputs = [ "out" "man" ];
+
+  # Setup hook variables.
+  inherit swift;
+  inherit (swift)
+    swiftOs swiftArch
+    swiftModuleSubdir swiftLibSubdir
+    swiftStaticModuleSubdir swiftStaticLibSubdir;
+
+  passAsFile = [ "buildCommand" ];
+  buildCommand = ''
+    mkdir -p $out/bin $out/nix-support
+
+    # Symlink all Swift binaries first.
+    # NOTE: This specifically omits clang binaries. We want to hide these for
+    # private use by Swift only.
+    ln -s -t $out/bin/ $swift/bin/swift*
+
+    # Replace specific binaries with wrappers.
+    for executable in swift swiftc swift-frontend; do
+      export prog=$swift/bin/$executable
+      rm $out/bin/$executable
+      substituteAll '${./wrapper.sh}' $out/bin/$executable
+      chmod a+x $out/bin/$executable
+    done
+
+    ln -s ${swift.man} $man
+
+    # This link is here because various tools (swiftpm) check for stdlib
+    # relative to the swift compiler. It's fine if this is for build-time
+    # stuff, but we should patch all cases were it would end up in an output.
+    ln -s ${swift.lib}/lib $out/lib
+
+    substituteAll ${./setup-hook.sh} $out/nix-support/setup-hook
+  '';
+
+  passthru = {
+    inherit swift;
+    inherit (swift) swiftOs swiftArch swiftModuleSubdir swiftLibSubdir;
+  };
+})

pkgs/development/compilers/swift/wrapper/setup-hook.sh

···
+# Add import paths for build inputs.
+swiftWrapper_addImports () {
+    # Include subdirectories following both the Swift platform convention, and
+    # a simple `lib/swift` for Nix convenience.
+    for subdir in @swiftModuleSubdir@ @swiftStaticModuleSubdir@ lib/swift; do
+        if [[ -d "$1/$subdir" ]]; then
+            export NIX_SWIFTFLAGS_COMPILE+=" -I $1/$subdir"
+        fi
+    done
+    for subdir in @swiftLibSubdir@ @swiftStaticLibSubdir@ lib/swift; do
+        if [[ -d "$1/$subdir" ]]; then
+            export NIX_LDFLAGS+=" -L $1/$subdir"
+        fi
+    done
+}
+
+addEnvHooks "$targetOffset" swiftWrapper_addImports
+
+# Use a postHook here because we rely on NIX_CC, which is set by the cc-wrapper
+# setup hook, so delay until we're sure it was run.
+swiftWrapper_postHook () {
+    # On Darwin, libc also contains Swift modules.
+    if [[ -e "$NIX_CC/nix-support/orig-libc" ]]; then
+        swiftWrapper_addImports "$(<$NIX_CC/nix-support/orig-libc)"
+    fi
+}
+
+postHooks+=(swiftWrapper_postHook)

pkgs/development/compilers/swift/wrapper/wrapper.sh

···
+#! @shell@
+# NOTE: This wrapper is derived from cc-wrapper.sh, and is hopefully somewhat
+# diffable with the original, so changes can be merged if necessary.
+set -eu -o pipefail +o posix
+shopt -s nullglob
+
+if (( "${NIX_DEBUG:-0}" >= 7 )); then
+    set -x
+fi
+
+cc_wrapper="${NIX_CC:-@default_cc_wrapper@}"
+
+source $cc_wrapper/nix-support/utils.bash
+
+expandResponseParams "$@"
+
+# Check if we should wrap this Swift invocation at all, and how. Specifically,
+# there are some internal tools we don't wrap, plus swift-frontend doesn't link
+# and doesn't understand linker flags. This follows logic in
+# `lib/DriverTool/driver.cpp`.
+prog=@prog@
+progName="$(basename "$prog")"
+firstArg="${params[0]:-}"
+isFrontend=0
+isRepl=0
+
+# These checks follow `shouldRunAsSubcommand`.
+if [[ "$progName" == swift ]]; then
+    case "$firstArg" in
+        "" | -* | *.* | */* | repl)
+            ;;
+        *)
+            exec "swift-$firstArg" "${params[@]:1}"
+            ;;
+    esac
+fi
+
+# These checks follow the first part of `run_driver`.
+#
+# NOTE: The original function short-circuits, but we can't here, because both
+# paths must be wrapped. So we use an 'isFrontend' flag instead.
+case "$firstArg" in
+    -frontend)
+        isFrontend=1
+        # Ensure this stays the first argument.
+        params=( "${params[@]:1}" )
+        extraBefore+=( "-frontend" )
+        ;;
+    -modulewrap)
+        # Don't wrap this integrated tool.
+        exec "$prog" "${params[@]}"
+        ;;
+    repl)
+        isRepl=1
+        params=( "${params[@]:1}" )
+        ;;
+    --driver-mode=*)
+        ;;
+    *)
+        if [[ "$progName" == swift-frontend ]]; then
+            isFrontend=1
+        fi
+        ;;
+esac
+
+path_backup="$PATH"
+
+# That @-vars are substituted separately from bash evaluation makes
+# shellcheck think this, and others like it, are useless conditionals.
+# shellcheck disable=SC2157
+if [[ -n "@coreutils_bin@" && -n "@gnugrep_bin@" ]]; then
+    PATH="@coreutils_bin@/bin:@gnugrep_bin@/bin"
+fi
+
+# Parse command line options and set several variables.
+# For instance, figure out if linker flags should be passed.
+# GCC prints annoying warnings when they are not needed.
+isCxx=0
+dontLink=$isFrontend
+
+for p in "${params[@]}"; do
+    case "$p" in
+        -enable-cxx-interop)
+            isCxx=1 ;;
+    esac
+done
+
+# NOTE: We don't modify these for Swift, but sourced scripts may use them.
+cxxInclude=1
+cxxLibrary=1
+cInclude=1
+
+linkType=$(checkLinkType "${params[@]}")
+
+# Optionally filter out paths not refering to the store.
+if [[ "${NIX_ENFORCE_PURITY:-}" = 1 && -n "$NIX_STORE" ]]; then
+    kept=()
+    nParams=${#params[@]}
+    declare -i n=0
+    while (( "$n" < "$nParams" )); do
+        p=${params[n]}
+        p2=${params[n+1]:-} # handle `p` being last one
+        n+=1
+
+        skipNext=false
+        path=""
+        case "$p" in
+            -[IL]/*) path=${p:2} ;;
+            -[IL]) path=$p2 skipNext=true ;;
+        esac
+
+        if [[ -n $path ]] && badPath "$path"; then
+            skip "$path"
+            $skipNext && n+=1
+            continue
+        fi
+
+        kept+=("$p")
+    done
+    # Old bash empty array hack
+    params=(${kept+"${kept[@]}"})
+fi
+
+# Flirting with a layer violation here.
+if [ -z "${NIX_BINTOOLS_WRAPPER_FLAGS_SET_@suffixSalt@:-}" ]; then
+    source @bintools@/nix-support/add-flags.sh
+fi
+
+# Put this one second so libc ldflags take priority.
+if [ -z "${NIX_CC_WRAPPER_FLAGS_SET_@suffixSalt@:-}" ]; then
+    source $cc_wrapper/nix-support/add-flags.sh
+fi
+
+if [[ "$isCxx" = 1 ]]; then
+    if [[ "$cxxInclude" = 1 ]]; then
+        NIX_CFLAGS_COMPILE_@suffixSalt@+=" $NIX_CXXSTDLIB_COMPILE_@suffixSalt@"
+    fi
+    if [[ "$cxxLibrary" = 1 ]]; then
+        NIX_CFLAGS_LINK_@suffixSalt@+=" $NIX_CXXSTDLIB_LINK_@suffixSalt@"
+    fi
+fi
+
+source $cc_wrapper/nix-support/add-hardening.sh
+
+# Add the flags for the C compiler proper.
+addCFlagsToList() {
+    declare -n list="$1"
+    shift
+
+    for ((i = 1; i <= $#; i++)); do
+        local val="${!i}"
+        case "$val" in
+            # Pass through using -Xcc, but also convert to Swift -I.
+            # These have slightly different meaning for Clang, but Swift
+            # doesn't have exact equivalents.
+            -isystem | -idirafter)
+                i=$((i + 1))
+                list+=("-Xcc" "$val" "-Xcc" "${!i}" "-I" "${!i}")
+                ;;
+            # Simple rename.
+            -iframework)
+                i=$((i + 1))
+                list+=("-Fsystem" "${!i}")
+                ;;
+            # Pass through verbatim.
+            -I | -Fsystem)
+                i=$((i + 1))
+                list+=("${val}" "${!i}")
+                ;;
+            -I* | -L* | -F*)
+                list+=("${val}")
+                ;;
+            # Pass through using -Xcc.
+            *)
+                list+=("-Xcc" "$val")
+                ;;
+        esac
+    done
+}
+for i in ${NIX_SWIFTFLAGS_COMPILE:-}; do
+    extraAfter+=("$i")
+done
+for i in ${NIX_SWIFTFLAGS_COMPILE_BEFORE:-}; do
+    extraBefore+=("$i")
+done
+addCFlagsToList extraAfter $NIX_CFLAGS_COMPILE_@suffixSalt@
+addCFlagsToList extraBefore ${hardeningCFlags[@]+"${hardeningCFlags[@]}"} $NIX_CFLAGS_COMPILE_BEFORE_@suffixSalt@
+
+if [ "$dontLink" != 1 ]; then
+
+    # Add the flags that should only be passed to the compiler when
+    # linking.
+    addCFlagsToList extraAfter $(filterRpathFlags "$linkType" $NIX_CFLAGS_LINK_@suffixSalt@)
+
+    # Add the flags that should be passed to the linker (and prevent
+    # `ld-wrapper' from adding NIX_LDFLAGS_@suffixSalt@ again).
+    for i in $(filterRpathFlags "$linkType" $NIX_LDFLAGS_BEFORE_@suffixSalt@); do
+        extraBefore+=("-Xlinker" "$i")
+    done
+    if [[ "$linkType" == dynamic && -n "$NIX_DYNAMIC_LINKER_@suffixSalt@" ]]; then
+        extraBefore+=("-Xlinker" "-dynamic-linker=$NIX_DYNAMIC_LINKER_@suffixSalt@")
+    fi
+    for i in $(filterRpathFlags "$linkType" $NIX_LDFLAGS_@suffixSalt@); do
+        if [ "${i:0:3}" = -L/ ]; then
+            extraAfter+=("$i")
+        else
+            extraAfter+=("-Xlinker" "$i")
+        fi
+    done
+    export NIX_LINK_TYPE_@suffixSalt@=$linkType
+fi
+
+# TODO: If we ever need to expand functionality of this hook, it may no longer
+# be compatible with Swift. Right now, it is only used on Darwin to force
+# -target, which also happens to work with Swift.
+if [[ -e $cc_wrapper/nix-support/add-local-cc-cflags-before.sh ]]; then
+    source $cc_wrapper/nix-support/add-local-cc-cflags-before.sh
+fi
+
+# May need to transform the triple injected by the above.
+for ((i = 1; i < ${#extraBefore[@]}; i++)); do
+    if [[ "${extraBefore[i]}" = -target ]]; then
+        i=$((i + 1))
+        # On Darwin only, need to change 'aarch64' to 'arm64'.
+        extraBefore[i]="${extraBefore[i]/aarch64-apple-/arm64-apple-}"
+        # On Darwin, Swift requires the triple to be annotated with a version.
+        # TODO: Assumes macOS.
+        extraBefore[i]="${extraBefore[i]/-apple-darwin/-apple-macosx${MACOSX_DEPLOYMENT_TARGET:-11.0}}"
+        break
+    fi
+done
+
+# As a very special hack, if the arguments are just `-v', then don't
+# add anything.  This is to prevent `gcc -v' (which normally prints
+# out the version number and returns exit code 0) from printing out
+# `No input files specified' and returning exit code 1.
+if [ "$*" = -v ]; then
+    extraAfter=()
+    extraBefore=()
+fi
+
+# Optionally print debug info.
+if (( "${NIX_DEBUG:-0}" >= 1 )); then
+    # Old bash workaround, see ld-wrapper for explanation.
+    echo "extra flags before to $prog:" >&2
+    printf "  %q\n" ${extraBefore+"${extraBefore[@]}"}  >&2
+    echo "original flags to $prog:" >&2
+    printf "  %q\n" ${params+"${params[@]}"} >&2
+    echo "extra flags after to $prog:" >&2
+    printf "  %q\n" ${extraAfter+"${extraAfter[@]}"} >&2
+fi
+
+PATH="$path_backup"
+# Old bash workaround, see above.
+
+if (( "${NIX_CC_USE_RESPONSE_FILE:-@use_response_file_by_default@}" >= 1 )); then
+    exec "$prog" @<(printf "%q\n" \
+       ${extraBefore+"${extraBefore[@]}"} \
+       ${params+"${params[@]}"} \
+       ${extraAfter+"${extraAfter[@]}"})
+else
+    exec "$prog" \
+       ${extraBefore+"${extraBefore[@]}"} \
+       ${params+"${params[@]}"} \
+       ${extraAfter+"${extraAfter[@]}"}
+fi

pkgs/os-specific/darwin/apple-sdk-11.0/default.nix

···
 , xar, cpio, python3, pbzx }:
 
 let
-  MacOSX-SDK = stdenvNoCC.mkDerivation rec {
-    pname = "MacOSX-SDK";
-    version = "11.0.0";
-
-    # https://swscan.apple.com/content/catalogs/others/index-11-10.15-10.14-10.13-10.12-10.11-10.10-10.9-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog
-    src = fetchurl {
-      url = "http://swcdn.apple.com/content/downloads/46/21/001-89745-A_56FM390IW5/v1um2qppgfdnam2e9cdqcqu2r6k8aa3lis/CLTools_macOSNMOS_SDK.pkg";
-      sha256 = "0n425smj4q1vxbza8fzwnk323fyzbbq866q32w288c44hl5yhwsf";
-    };
-
+  mkSusDerivation = args: stdenvNoCC.mkDerivation (args // {
     dontBuild = true;
     darwinDontCodeSign = true;
 
···
       pbzx $src | cpio -idm
     '';
 
+    passthru = {
+      inherit (args) version;
+    };
+  });
+
+  MacOSX-SDK = mkSusDerivation {
+    pname = "MacOSX-SDK";
+    version = "11.0.0";
+
+    # https://swscan.apple.com/content/catalogs/others/index-11-10.15-10.14-10.13-10.12-10.11-10.10-10.9-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog
+    src = fetchurl {
+      url = "http://swcdn.apple.com/content/downloads/46/21/001-89745-A_56FM390IW5/v1um2qppgfdnam2e9cdqcqu2r6k8aa3lis/CLTools_macOSNMOS_SDK.pkg";
+      sha256 = "0n425smj4q1vxbza8fzwnk323fyzbbq866q32w288c44hl5yhwsf";
+    };
+
     installPhase = ''
       cd Library/Developer/CommandLineTools/SDKs/MacOSX11.1.sdk
 
       mkdir $out
       cp -r System usr $out/
     '';
+  };
 
-    passthru = {
-      inherit version;
+  CLTools_Executables = mkSusDerivation {
+    pname = "CLTools_Executables";
+    version = "11.0.0";
+
+    # https://swscan.apple.com/content/catalogs/others/index-11-10.15-10.14-10.13-10.12-10.11-10.10-10.9-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog
+    src = fetchurl {
+      url = "http://swcdn.apple.com/content/downloads/46/21/001-89745-A_56FM390IW5/v1um2qppgfdnam2e9cdqcqu2r6k8aa3lis/CLTools_Executables.pkg";
+      sha256 = "0nvb1qx7l81l2wcl8wvgbpsg5rcn51ylhivqmlfr2hrrv3zrrpl0";
     };
+
+    installPhase = ''
+      cd Library/Developer/CommandLineTools
+
+      mkdir $out
+      cp -r Library usr $out/
+    '';
   };
 
   callPackage = newScope (packages // pkgs.darwin // { inherit MacOSX-SDK; });
···
 
     # TODO: this is nice to be private. is it worth the callPackage above?
     # Probably, I don't think that callPackage costs much at all.
-    inherit MacOSX-SDK;
+    inherit MacOSX-SDK CLTools_Executables;
 
     Libsystem = callPackage ./libSystem.nix {};
     LibsystemCross = pkgs.darwin.Libsystem;

pkgs/top-level/all-packages.nix

···
 
   svdtools = callPackage ../development/embedded/svdtools { };
 
-  swift = callPackage ../development/compilers/swift { };
+  swiftPackages = recurseIntoAttrs (callPackage ../development/compilers/swift { });
+  inherit (swiftPackages) swift;
 
   swiProlog = callPackage ../development/compilers/swi-prolog {
     openssl = openssl_1_1;