swift: WIP darwin support

- Needs cleanup

- Need to check if swift-nix-toolchain.patch is still necessary.

- Should enable verbose-build, IMHO

- Can we build less? Tweak buildbot_linux preset?

- Currently fails at:

  [3400/3403][ 99%][2567.938s] Performing build step for 'compiler-rt'
  [104/806][ 12%][0.798s] Building C object lib/builtins/CMakeFiles/clang_rt.cc_kext_x86_64_osx.dir/os_version_check.c.o
  FAILED: lib/builtins/CMakeFiles/clang_rt.cc_kext_x86_64_osx.dir/os_version_check.c.o
  /tmp/nix-build-swift-5.1.1.drv-0/build/buildbot_linux/llvm-macosx-x86_64/./bin/clang -DKERNEL_USE  -O3 -DNDEBUG -arch x86_64 -isysroot /nix/store/afpv8r50svbrmdmk56wcwpzyp5zac3l5-SDKs/MacOSX10.12.sdk  -isysroot /nix/store/afpv8r50svbrmdmk56wcwpzyp5zac3l5-SDKs/MacOSX10.12.sdk -mmacosx-version-min=10.5 -fPIC -O3 -fvisibility=hidden -DVISIBILITY_HIDDEN -Wall -fomit-frame-pointer -arch x86_64 -mkernel -MD -MT lib/builtins/CMakeFiles/clang_rt.cc_kext_x86_64_osx.dir/os_version_check.c.o -MF lib/builtins/CMakeFiles/clang_rt.cc_kext_x86_64_osx.dir/os_version_check.c.o.d -o lib/builtins/CMakeFiles/clang_rt.cc_kext_x86_64_osx.dir/os_version_check.c.o -c /tmp/nix-build-swift-5.1.1.drv-0/src/llvm/projects/compiler-rt/lib/builtins/os_version_check.c
  /tmp/nix-build-swift-5.1.1.drv-0/src/llvm/projects/compiler-rt/lib/builtins/os_version_check.c:18:10: fatal error: 'TargetConditionals.h' file not found
  #include <TargetConditionals.h>
           ^~~~~~~~~~~~~~~~~~~~~~
  1 error generated.
  [113/806][ 14%][0.848s] Building C object lib/builtins/CMakeFiles/clang_rt.cc_kext_x86_64_osx.dir/popcountti2.c.o
  ninja: build stopped: subcommand failed.
  FAILED: tools/clang/runtime/compiler-rt-stamps/compiler-rt-build
  cd /tmp/nix-build-swift-5.1.1.drv-0/build/buildbot_linux/llvm-macosx-x86_64/tools/clang/runtime/compiler-rt-bins && /nix/store/mrz74myz60ig4asl3ldrch86mhwlfsai-cmake-3.18.4/bin/cmake --build . && /nix/store/mrz74myz60ig4asl3ldrch86mhwlfsai-cmake-3.18.4/bin/cmake -E touch /tmp/nix-build-swift-5.1.1.drv-0/build/buildbot_linux/llvm-macosx-x86_64/tools/clang/runtime/compiler-rt-stamps//compiler-rt-build
  ninja: build stopped: subcommand failed.

pkgs/development/compilers/swift/default.nix

@@ -32,6 +32,8 @@
 , makeWrapper
 , gnumake
 , file
+, darwin
+, xcbuild
 }:
 
 let
@@ -107,23 +109,27 @@ let
 
   devInputs = [
     curl
-    glibc
     icu
     libblocksruntime
     libbsd
     libedit
-    libuuid
     libxml2
     ncurses
     sqlite
     swig
-  ];
+  ]
+    ++ stdenv.lib.optionals stdenv.isLinux [
+      glibc
+      libuuid
+    ];
 
   cmakeFlags = [
-    "-DGLIBC_INCLUDE_PATH=${stdenv.cc.libc.dev}/include"
     "-DC_INCLUDE_DIRS=${stdenv.lib.makeSearchPathOutput "dev" "include" devInputs}:${libxml2.dev}/include/libxml2"
     "-DGCC_INSTALL_PREFIX=${gccForLibs}"
-  ];
+  ]
+    ++ stdenv.lib.optionals stdenv.isLinux [
+      "-DGLIBC_INCLUDE_PATH=${stdenv.cc.libc.dev}/include"
+    ];
 
 in
 stdenv.mkDerivation {
@@ -137,18 +143,25 @@ stdenv.mkDerivation {
     coreutils
     findutils
     gnumake
-    libtool
     makeWrapper
     ninja
     perl
     pkgconfig
     python
     rsync
     which
-  ];
-  buildInputs = devInputs ++ [
-    clang
-  ];
+  ]
+    ++ (stdenv.lib.optionals stdenv.isLinux [
+      libtool
+    ])
+    ++ (stdenv.lib.optionals stdenv.isDarwin [
+      xcbuild clang darwin.cctools darwin.PowerManagement
+    ]);
+
+  buildInputs = devInputs
+    ++ (stdenv.lib.optionals stdenv.isLinux [
+      clang
+    ]);
 
   # TODO: Revisit what's propagated and how
   propagatedBuildInputs = [
@@ -198,14 +211,16 @@ stdenv.mkDerivation {
       -e 's|/usr/bin/file|${file}/bin/file|g'
 
     substituteInPlace swift/stdlib/public/Platform/CMakeLists.txt \
-      --replace '/usr/include' "${stdenv.cc.libc.dev}/include"
+      --replace '/usr/include' "${stdenv.cc.libc_dev}/include"
     substituteInPlace swift/utils/build-script-impl \
       --replace '/usr/include/c++' "${gccForLibs}/include/c++"
     patch -p1 -d swift -i ${./patches/glibc-arch-headers.patch}
     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/swift-darwin-sandbox.patch}
+    patch -p1 -d swift -i ${./patches/swift-nix-toolchain.patch}
 
     sed -i swift/utils/build-presets.ini \
       -e 's/^test-installable-package$/# \0/' \
@@ -217,17 +232,22 @@ stdenv.mkDerivation {
       \
       -e 's/^swift-install-components=autolink.*$/\0;editor-integration/'
 
+    ${stdenv.lib.optionalString stdenv.isLinux ''
     substituteInPlace clang/lib/Driver/ToolChains/Linux.cpp \
       --replace 'SysRoot + "/lib' '"${glibc}/lib" "'
     substituteInPlace clang/lib/Driver/ToolChains/Linux.cpp \
       --replace 'SysRoot + "/usr/lib' '"${glibc}/lib" "'
+    ''}
     patch -p1 -d clang -i ${./patches/llvm-toolchain-dir.patch}
     patch -p1 -d clang -i ${./purity.patch}
 
     # Workaround hardcoded dep on "libcurses" (vs "libncurses"):
     sed -i 's/curses/ncurses/' llbuild/*/*/CMakeLists.txt
+
     # uuid.h is not part of glibc, but of libuuid
+    ${stdenv.lib.optionalString (libuuid != null) ''
     sed -i 's|''${GLIBC_INCLUDE_PATH}/uuid/uuid.h|${libuuid.dev}/include/uuid/uuid.h|' swift/stdlib/public/Platform/glibc.modulemap.gyb
+    ''}
 
     # Compatibility with glibc 2.30
     # Adapted from https://github.com/apple/swift-package-manager/pull/2408
@@ -295,7 +315,10 @@ stdenv.mkDerivation {
     rm $SWIFT_SOURCE_ROOT/swift/validation-test/Python/build_swift.swift  # install_prefix not passed properly
 
     # match the swift wrapper in the install phase
-    export LIBRARY_PATH=${icu}/lib:${libuuid.out}/lib
+    export LIBRARY_PATH=${icu}/lib
+    ${stdenv.lib.optionalString (libuuid != null) ''
+    export LIBRARY_PATH=${libuuid.out}/lib:$LIBRARY_PATH
+    ''}
 
     checkTarget=check-swift-all
     ninjaFlags='-C buildbot_linux/swift-${stdenv.hostPlatform.parsed.kernel.name}-${stdenv.hostPlatform.parsed.cpu.name}'
@@ -314,10 +337,15 @@ stdenv.mkDerivation {
     rmdir $out/local/include $out/local
     rm -r $out/bin/sdk-module-lists $out/bin/swift-api-checker.py
 
+    export LIBRARY_PATH=${icu}/lib
+    ${stdenv.lib.optionalString (libuuid != null) ''
+    export LIBRARY_PATH=${libuuid.out}/lib:$LIBRARY_PATH
+    ''}
+
     wrapProgram $out/bin/swift \
       --suffix C_INCLUDE_PATH : $out/lib/swift/clang/include \
       --suffix CPLUS_INCLUDE_PATH : $out/lib/swift/clang/include \
-      --suffix LIBRARY_PATH : ${icu}/lib:${libuuid.out}/lib
+      --suffix LIBRARY_PATH : $LIBRARY_PATH
   '';
 
   # Hack to avoid build and install directories in RPATHs.
@@ -329,7 +357,7 @@ stdenv.mkDerivation {
     maintainers = with maintainers; [ dtzWill ];
     license = licenses.asl20;
     # Swift doesn't support 32bit Linux, unknown on other platforms.
-    platforms = platforms.linux;
+    platforms = platforms.linux ++ platforms.darwin;
     badPlatforms = platforms.i686;
     broken = stdenv.isAarch64; # 2018-09-04, never built on Hydra
   };

pkgs/development/compilers/swift/patches/swift-darwin-sandbox.patch

@@ -0,0 +1,21 @@
+Disable Darwin build-time checks broken within the sandbox
+
+--- a/utils/swift_build_support/swift_build_support/host.py
++++ b/utils/swift_build_support/swift_build_support/host.py
+@@ -44,7 +44,6 @@ def _darwin_system_memory():
+
+
+ _PER_PLATFORM_SYSTEM_MEMORY = {
+-    ('Darwin', 'x86_64'): _darwin_system_memory
+ }
+
+
+@@ -79,8 +78,6 @@ def _darwin_max_num_swift_parallel_lto_link_jobs():
+
+
+ _PER_PLATFORM_MAX_PARALLEL_LTO_JOBS = {
+-    ('Darwin', 'x86_64'): (_darwin_max_num_llvm_parallel_lto_link_jobs,
+-                           _darwin_max_num_swift_parallel_lto_link_jobs)
+ }
+
+

pkgs/development/compilers/swift/patches/swift-nix-toolchain.patch

@@ -0,0 +1,30 @@
+Force PATH lookup of toolchain on all platforms
+
+--- a/utils/swift_build_support/swift_build_support/toolchain.py
++++ b/utils/swift_build_support/swift_build_support/toolchain.py
+@@ -16,6 +16,7 @@ Represent toolchain - the versioned executables.
+
+ from __future__ import absolute_import
+
++import os
+ import platform
+
+ from . import cache_util
+@@ -192,9 +193,16 @@ class Haiku(GenericUnix):
+         super(Haiku, self)
+
+
++class Nix(GenericUnix):
++    def __init__(self):
++        super(Nix, self).__init__([''])
++
++
+ def host_toolchain(**kwargs):
+     sys = platform.system()
+-    if sys == 'Darwin':
++    if 'NIX_BUILD_TOP' in os.environ:
++        return Nix()
++    elif sys == 'Darwin':
+         return MacOSX(kwargs.pop('xcrun_toolchain', 'default'))
+     elif sys == 'Linux':
+         return Linux()