build: attempt to add swift support to cmake

cmake/modules/SwiftSupport.cmake

@@ -0,0 +1,69 @@
+
+include(CMakeParseArguments)
+
+function(add_swift_library library)
+  set(options)
+  set(single_value_options MODULE_NAME;MODULE_LINK_NAME;MODULE_PATH;MODULE_CACHE_PATH;OUTPUT)
+  set(multiple_value_options SOURCES;SWIFT_FLAGS;CFLAGS)
+
+  cmake_parse_arguments(ASL "${options}" "${single_value_options}" "${multiple_value_options}" ${ARGN})
+
+  set(flags ${CMAKE_SWIFT_FLAGS})
+
+  list(APPEND flags -emit-library)
+
+  if(ASL_MODULE_NAME)
+    list(APPEND flags -module-name;${ASL_MODULE_NAME})
+  endif()
+  if(ASL_MODULE_LINK_NAME)
+    list(APPEND flags -module-link-name;${ASL_MODULE_LINK_NAME})
+  endif()
+  if(ASL_MODULE_PATH)
+    list(APPEND flags -emit-module-path;${ASL_MODULE_PATH})
+  endif()
+  if(ASL_MODULE_CACHE_PATH)
+    list(APPEND flags -module-cache-path;${ASL_MODULE_CACHE_PATH})
+  endif()
+  if(ASL_SWIFT_FLAGS)
+    foreach(flag ${ASL_SWIFT_FLAGS})
+      list(APPEND flags ${flag})
+    endforeach()
+  endif()
+  if(ASL_CFLAGS)
+    foreach(flag ${ASL_CFLAGS})
+      list(APPEND flags -Xcc;${flag})
+    endforeach()
+  endif()
+
+  # FIXME: We shouldn't /have/ to build things in a single process.
+  # <rdar://problem/15972329>
+  list(APPEND flags -force-single-frontend-invocation)
+
+  set(sources)
+  foreach(source ${ASL_SOURCES})
+    get_filename_component(location ${source} PATH)
+    if(IS_ABSOLUTE ${location})
+      list(APPEND sources ${source})
+    else()
+      list(APPEND sources ${CMAKE_CURRENT_SOURCE_DIR}/${source})
+    endif()
+  endforeach()
+
+  get_filename_component(module_directory ${ASL_MODULE_PATH} DIRECTORY)
+
+  add_custom_command(OUTPUT
+                       ${ASL_OUTPUT}
+                       ${ASL_MODULE_PATH}
+                       ${moodule_directory}/${ASL_MODULE_NAME}.swiftdoc
+                     DEPENDS
+                       ${ASL_SOURCES}
+                     COMMAND
+                       ${CMAKE_COMMAND} -E make_directory ${module_directory}
+                     COMMAND
+                       ${CMAKE_SWIFT_COMPILER} ${flags} -c ${sources} -o ${ASL_OUTPUT})
+  add_custom_target(${library}
+                    DEPENDS
+                       ${ASL_OUTPUT}
+                       ${ASL_MODULE_PATH}
+                       ${moodule_directory}/${ASL_MODULE_NAME}.swiftdoc)
+endfunction()

src/CMakeLists.txt

@@ -1,8 +1,44 @@
 
+include(SwiftSupport)
+
 set(dispatch_BLOCK_SOURCES block.cpp)
 if(HAVE_OBJC)
   list(APPEND dispatch_BLOCK_SOURCES data.m object.m)
 endif()
+set(dispatch_SWIFT_SOURCES)
+if(CMAKE_SWIFT_COMPILER)
+  set(swift_optimization_flags)
+  if(CMAKE_BUILD_TYPE MATCHES Release)
+    set(swift_optimization_flags -O)
+  endif()
+  add_swift_library(swiftDispatch
+                    MODULE_NAME
+                      Dispatch
+                    MODULE_LINK_NAME
+                      dispatch
+                    MODULE_PATH
+                      ${CMAKE_CURRENT_BINARY_DIR}/swift/Dispatch.swiftmodule
+                    OUTPUT
+                      ${CMAKE_CURRENT_BINARY_DIR}/swiftDispatch.o
+                    SOURCES
+                      swift/Block.swift
+                      swift/Data.swift
+                      swift/Dispatch.swift
+                      swift/IO.swift
+                      swift/Private.swift
+                      swift/Queue.swift
+                      swift/Source.swift
+                      swift/Time.swift
+                      swift/Wrapper.swift
+                    CFLAGS
+                      -fblocks
+                      -fmodule-map-file=${CMAKE_SOURCE_DIR}/dispatch/module.modulemap
+                    SWIFT_FLAGS
+                      -I ${CMAKE_SOURCE_DIR}
+                      ${swift_optimization_flags})
+  list(APPEND dispatch_SWIFT_SOURCES
+       swift/DispatchStubs.cc;${CMAKE_CURRENT_BINARY_DIR}/swiftDispatch.o)
+endif()
 add_library(dispatch
               allocator.c
               apply.c
@@ -55,7 +91,8 @@ add_library(dispatch
               shims/time.h
               shims/tsd.h
               shims/yield.h
-              ${dispatch_BLOCK_SOURCES})
+              ${dispatch_BLOCK_SOURCES}
+              ${dispatch_SWIFT_SOURCES})
 target_include_directories(dispatch
                            PRIVATE
                              ${CMAKE_BINARY_DIR}