[staging-next] swift: bootstrap using system stdlib

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

@@ -36,6 +36,7 @@
 , CoreServices
 , Foundation
 , Combine
+, MacOSX-SDK
 , CLTools_Executables
 }:
 
@@ -169,6 +170,21 @@ let
     chmod a+x "$targetFile"
   '';
 
+  # On Darwin, we need to use BOOTSTRAPPING-WITH-HOSTLIBS because of ABI
+  # stability, and have to provide the definitions for the system stdlib.
+  appleSwiftCore = stdenv.mkDerivation {
+    name = "apple-swift-core";
+    dontUnpack = true;
+
+    installPhase = ''
+      mkdir -p $out/lib/swift
+      cp -r \
+        "${MacOSX-SDK}/usr/lib/swift/Swift.swiftmodule" \
+        "${MacOSX-SDK}/usr/lib/swift/libswiftCore.tbd" \
+        $out/lib/swift/
+    '';
+  };
+
 in stdenv.mkDerivation {
   pname = "swift";
   inherit (sources) version;
@@ -263,7 +279,6 @@ in stdenv.mkDerivation {
     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;
@@ -395,17 +410,31 @@ in stdenv.mkDerivation {
     "
     buildProject llvm llvm-project/llvm
 
+    '' + lib.optionalString stdenv.isDarwin ''
+    # Add appleSwiftCore to the search paths. We can't simply add it to
+    # buildInputs, because it is potentially an older stdlib than the one we're
+    # building. We have to remove it again after the main Swift build, or later
+    # build steps may fail. (Specific case: Concurrency backdeploy uses the
+    # Sendable protocol, which appears to not be present in the macOS 11 SDK.)
+    OLD_NIX_SWIFTFLAGS_COMPILE="$NIX_SWIFTFLAGS_COMPILE"
+    OLD_NIX_LDFLAGS="$NIX_LDFLAGS"
+    export NIX_SWIFTFLAGS_COMPILE+=" -I ${appleSwiftCore}/lib/swift"
+    export NIX_LDFLAGS+=" -L ${appleSwiftCore}/lib/swift"
+    '' + ''
+
     # Some notes:
-    # - Building with libswift defaults to OFF in CMake, but is enabled in
-    #   standard builds, so we enable it as well.
+    # - BOOTSTRAPPING_MODE defaults to OFF in CMake, but is enabled in standard
+    #   builds, so we enable it as well. On Darwin, we have to use the system
+    #   Swift libs because of ABI-stability, but this may be trouble if the
+    #   builder is an older macOS.
     # - Experimental features are OFF by default in CMake, but some are
     #   required to build the stdlib.
     # - SWIFT_STDLIB_ENABLE_OBJC_INTEROP is set explicitely because its check
     #   is buggy. (Uses SWIFT_HOST_VARIANT_SDK before initialized.)
     #   Fixed in: https://github.com/apple/swift/commit/84083afef1de5931904d5c815d53856cdb3fb232
     cmakeFlags="
       -GNinja
-      -DBOOTSTRAPPING_MODE=BOOTSTRAPPING
+      -DBOOTSTRAPPING_MODE=BOOTSTRAPPING${lib.optionalString stdenv.isDarwin "-WITH-HOSTLIBS"}
       -DSWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY=ON
       -DLLVM_DIR=$SWIFT_BUILD_ROOT/llvm/lib/cmake/llvm
       -DClang_DIR=$SWIFT_BUILD_ROOT/llvm/lib/cmake/clang
@@ -418,6 +447,12 @@ in stdenv.mkDerivation {
     "
     buildProject swift
 
+    '' + lib.optionalString stdenv.isDarwin ''
+    # Restore search paths to remove appleSwiftCore.
+    export NIX_SWIFTFLAGS_COMPILE="$OLD_NIX_SWIFTFLAGS_COMPILE"
+    export NIX_LDFLAGS="$OLD_NIX_LDFLAGS"
+    '' + ''
+
     # These are based on flags in `utils/build-script-impl`.
     #
     # LLDB_USE_SYSTEM_DEBUGSERVER=ON disables the debugserver build on Darwin,

pkgs/development/compilers/swift/default.nix

@@ -49,7 +49,7 @@ let
 
     swift-unwrapped = callPackage ./compiler {
       inherit (darwin) DarwinTools cctools sigtool;
-      inherit (apple_sdk) CLTools_Executables;
+      inherit (apple_sdk) MacOSX-SDK CLTools_Executables;
       inherit (apple_sdk.frameworks) CoreServices Foundation Combine;
     };
 

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

@@ -159,7 +159,7 @@
   ScreenSaver                      = {};
   ScreenTime                       = {};
   ScriptingBridge                  = {};
-  Security                         = { inherit IOKit libDER xpc; };
+  Security                         = { inherit IOKit libDER; };
   SecurityFoundation               = { inherit Security; };
   SecurityInterface                = { inherit Security SecurityFoundation; };
   SensorKit                        = {};