include(SwiftList)
include(SwiftXcodeSupport)
include(SwiftWindowsSupport)
include(SwiftAndroidSupport)

# SWIFTLIB_DIR is the directory in the build tree where Swift resource files
# should be placed.  Note that $CMAKE_CFG_INTDIR expands to "." for
# single-configuration builds.
set(SWIFTLIB_DIR
    "${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib/swift")
set(SWIFTSTATICLIB_DIR
    "${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib/swift_static")

function(add_dependencies_multiple_targets)
  cmake_parse_arguments(
      ADMT # prefix
      "" # options
      "" # single-value args
      "TARGETS;DEPENDS" # multi-value args
      ${ARGN})
  precondition(ADMT_UNPARSED_ARGUMENTS NEGATE MESSAGE "unrecognized arguments: ${ADMT_UNPARSED_ARGUMENTS}")

  if(NOT "${ADMT_DEPENDS}" STREQUAL "")
    foreach(target ${ADMT_TARGETS})
      add_dependencies("${target}" ${ADMT_DEPENDS})
    endforeach()
  endif()
endfunction()

# Compute the library subdirectory to use for the given sdk and
# architecture, placing the result in 'result_var_name'.
function(compute_library_subdir result_var_name sdk arch)
  if(sdk IN_LIST SWIFT_APPLE_PLATFORMS)
    set("${result_var_name}" "${SWIFT_SDK_${sdk}_LIB_SUBDIR}" PARENT_SCOPE)
  else()
    set("${result_var_name}" "${SWIFT_SDK_${sdk}_LIB_SUBDIR}/${arch}" PARENT_SCOPE)
  endif()
endfunction()

function(_compute_lto_flag option out_var)
  string(TOLOWER "${option}" lowercase_option)
  if (lowercase_option STREQUAL "full")
    set(${out_var} "-flto=full" PARENT_SCOPE)
  elseif (lowercase_option STREQUAL "thin")
    set(${out_var} "-flto=thin" PARENT_SCOPE)
  endif()
endfunction()

function(_set_target_prefix_and_suffix target kind sdk)
  precondition(target MESSAGE "target is required")
  precondition(kind MESSAGE "kind is required")
  precondition(sdk MESSAGE "sdk is required")

  if(${sdk} STREQUAL ANDROID)
    if(${kind} STREQUAL STATIC)
      set_target_properties(${target} PROPERTIES PREFIX "lib" SUFFIX ".a")
    elseif(${kind} STREQUAL SHARED)
      set_target_properties(${target} PROPERTIES PREFIX "lib" SUFFIX ".so")
    endif()
  elseif(${sdk} STREQUAL WINDOWS)
    if(${kind} STREQUAL STATIC)
      set_target_properties(${target} PROPERTIES PREFIX "" SUFFIX ".lib")
    elseif(${kind} STREQUAL SHARED)
      set_target_properties(${target} PROPERTIES PREFIX "" SUFFIX ".dll")
    endif()
  endif()
endfunction()

function(is_darwin_based_sdk sdk_name out_var)
  if ("${sdk_name}" STREQUAL "OSX" OR
      "${sdk_name}" STREQUAL "IOS" OR
      "${sdk_name}" STREQUAL "IOS_SIMULATOR" OR
      "${sdk_name}" STREQUAL "TVOS" OR
      "${sdk_name}" STREQUAL "TVOS_SIMULATOR" OR
      "${sdk_name}" STREQUAL "WATCHOS" OR
      "${sdk_name}" STREQUAL "WATCHOS_SIMULATOR")
    set(${out_var} TRUE PARENT_SCOPE)
  else()
    set(${out_var} FALSE PARENT_SCOPE)
  endif()
endfunction()

# Usage:
# _add_variant_c_compile_link_flags(
#   SDK sdk
#   ARCH arch
#   BUILD_TYPE build_type
#   ENABLE_LTO enable_lto
#   ANALYZE_CODE_COVERAGE analyze_code_coverage
#   RESULT_VAR_NAME result_var_name
#   DEPLOYMENT_VERSION_OSX version # If provided, overrides the default value of the OSX deployment target set by the Swift project for this compilation only.
#   DEPLOYMENT_VERSION_IOS version
#   DEPLOYMENT_VERSION_TVOS version
#   DEPLOYMENT_VERSION_WATCHOS version
#
# )
function(_add_variant_c_compile_link_flags)
  set(oneValueArgs SDK ARCH BUILD_TYPE RESULT_VAR_NAME ENABLE_LTO ANALYZE_CODE_COVERAGE
    DEPLOYMENT_VERSION_OSX DEPLOYMENT_VERSION_IOS DEPLOYMENT_VERSION_TVOS DEPLOYMENT_VERSION_WATCHOS)
  cmake_parse_arguments(CFLAGS
    ""
    "${oneValueArgs}"
    ""
    ${ARGN})

  set(result ${${CFLAGS_RESULT_VAR_NAME}})

  is_darwin_based_sdk("${CFLAGS_SDK}" IS_DARWIN)
  if(IS_DARWIN)
    # Check if there's a specific OS deployment version needed for this invocation
    if("${CFLAGS_SDK}" STREQUAL "OSX")
      set(DEPLOYMENT_VERSION ${CFLAGS_DEPLOYMENT_VERSION_OSX})
    elseif("${CFLAGS_SDK}" STREQUAL "IOS" OR "${CFLAGS_SDK}" STREQUAL "IOS_SIMULATOR")
      set(DEPLOYMENT_VERSION ${CFLAGS_DEPLOYMENT_VERSION_IOS})
    elseif("${CFLAGS_SDK}" STREQUAL "TVOS" OR "${CFLAGS_SDK}" STREQUAL "TVOS_SIMULATOR")
      set(DEPLOYMENT_VERSION ${CFLAGS_DEPLOYMENT_VERSION_TVOS})
    elseif("${CFLAGS_SDK}" STREQUAL "WATCHOS" OR "${CFLAGS_SDK}" STREQUAL "WATCHOS_SIMULATOR")
      set(DEPLOYMENT_VERSION ${CFLAGS_DEPLOYMENT_VERSION_WATCHOS})
    endif()

    if("${DEPLOYMENT_VERSION}" STREQUAL "")
      set(DEPLOYMENT_VERSION "${SWIFT_SDK_${CFLAGS_SDK}_DEPLOYMENT_VERSION}")
    endif()
  endif()

  # MSVC, clang-cl, gcc don't understand -target.
  if(CMAKE_C_COMPILER_ID MATCHES "^Clang|AppleClang$" AND
      NOT SWIFT_COMPILER_IS_MSVC_LIKE)
    list(APPEND result "-target" "${SWIFT_SDK_${CFLAGS_SDK}_ARCH_${CFLAGS_ARCH}_TRIPLE}${DEPLOYMENT_VERSION}")
  endif()

  set(_sysroot "${SWIFT_SDK_${CFLAGS_SDK}_ARCH_${CFLAGS_ARCH}_PATH}")
  if(IS_DARWIN)
    list(APPEND result "-isysroot" "${_sysroot}")
  elseif(NOT SWIFT_COMPILER_IS_MSVC_LIKE AND NOT "${_sysroot}" STREQUAL "/")
    list(APPEND result "--sysroot=${_sysroot}")
  endif()

  if("${CFLAGS_SDK}" STREQUAL "ANDROID")
    # lld can handle targeting the android build.  However, if lld is not
    # enabled, then fallback to the linker included in the android NDK.
    if(NOT SWIFT_ENABLE_LLD_LINKER)
      list(APPEND result "-B" "${SWIFT_SDK_ANDROID_ARCH_${CFLAGS_ARCH}_NDK_PREBUILT_PATH}/${SWIFT_SDK_ANDROID_ARCH_${CFLAGS_ARCH}_NDK_TRIPLE}/bin")
    endif()
  endif()

  if(IS_DARWIN)
    list(APPEND result
      "-arch" "${CFLAGS_ARCH}"
      "-F" "${SWIFT_SDK_${CFLAGS_SDK}_PATH}/../../../Developer/Library/Frameworks"
      "-m${SWIFT_SDK_${CFLAGS_SDK}_VERSION_MIN_NAME}-version-min=${DEPLOYMENT_VERSION}")
  endif()

  if(CFLAGS_ANALYZE_CODE_COVERAGE)
    list(APPEND result "-fprofile-instr-generate"
                       "-fcoverage-mapping")
  endif()

  _compute_lto_flag("${CFLAGS_ENABLE_LTO}" _lto_flag_out)
  if (_lto_flag_out)
    list(APPEND result "${_lto_flag_out}")
  endif()

  set("${CFLAGS_RESULT_VAR_NAME}" "${result}" PARENT_SCOPE)
endfunction()

function(_add_variant_c_compile_flags)
  set(oneValueArgs SDK ARCH BUILD_TYPE ENABLE_ASSERTIONS ANALYZE_CODE_COVERAGE
    DEPLOYMENT_VERSION_OSX DEPLOYMENT_VERSION_IOS DEPLOYMENT_VERSION_TVOS DEPLOYMENT_VERSION_WATCHOS
    RESULT_VAR_NAME ENABLE_LTO)
  cmake_parse_arguments(CFLAGS
    "FORCE_BUILD_OPTIMIZED"
    "${oneValueArgs}"
    ""
    ${ARGN})

  set(result ${${CFLAGS_RESULT_VAR_NAME}})

  _add_variant_c_compile_link_flags(
    SDK "${CFLAGS_SDK}"
    ARCH "${CFLAGS_ARCH}"
    BUILD_TYPE "${CFLAGS_BUILD_TYPE}"
    ENABLE_ASSERTIONS "${CFLAGS_ENABLE_ASSERTIONS}"
    ENABLE_LTO "${CFLAGS_ENABLE_LTO}"
    ANALYZE_CODE_COVERAGE FALSE
    DEPLOYMENT_VERSION_OSX "${CFLAGS_DEPLOYMENT_VERSION_OSX}"
    DEPLOYMENT_VERSION_IOS "${CFLAGS_DEPLOYMENT_VERSION_IOS}"
    DEPLOYMENT_VERSION_TVOS "${CFLAGS_DEPLOYMENT_VERSION_TVOS}"
    DEPLOYMENT_VERSION_WATCHOS "${CFLAGS_DEPLOYMENT_VERSION_WATCHOS}"
    RESULT_VAR_NAME result)

  is_build_type_optimized("${CFLAGS_BUILD_TYPE}" optimized)
  if(optimized OR CFLAGS_FORCE_BUILD_OPTIMIZED)
    list(APPEND result "-O2")

    # Omit leaf frame pointers on x86 production builds (optimized, no debug
    # info, and no asserts).
    is_build_type_with_debuginfo("${CFLAGS_BUILD_TYPE}" debug)
    if(NOT debug AND NOT CFLAGS_ENABLE_ASSERTIONS)
      if("${CFLAGS_ARCH}" STREQUAL "i386" OR "${CFLAGS_ARCH}" STREQUAL "i686")
        if(NOT SWIFT_COMPILER_IS_MSVC_LIKE)
          list(APPEND result "-momit-leaf-frame-pointer")
        else()
          list(APPEND result "/Oy")
        endif()
      endif()
    endif()
  else()
    if(NOT SWIFT_COMPILER_IS_MSVC_LIKE)
      list(APPEND result "-O0")
    else()
      list(APPEND result "/Od")
    endif()
  endif()

  # CMake automatically adds the flags for debug info if we use MSVC/clang-cl.
  if(NOT SWIFT_COMPILER_IS_MSVC_LIKE)
    is_build_type_with_debuginfo("${CFLAGS_BUILD_TYPE}" debuginfo)
    if(debuginfo)
      _compute_lto_flag("${CFLAGS_ENABLE_LTO}" _lto_flag_out)
      if(_lto_flag_out)
        list(APPEND result "-gline-tables-only")
      else()
        list(APPEND result "-g")
      endif()
    else()
      list(APPEND result "-g0")
    endif()
  endif()

  if("${CFLAGS_SDK}" STREQUAL "WINDOWS")
    # MSVC doesn't support -Xclang. We don't need to manually specify
    # -D_MD or D_MDd either, as CMake does this automatically.
    if(NOT "${CMAKE_C_COMPILER_ID}" STREQUAL "MSVC")
      list(APPEND result -Xclang;--dependent-lib=oldnames)
      # TODO(compnerd) handle /MT, /MTd
      if("${CFLAGS_BUILD_TYPE}" STREQUAL "Debug")
        list(APPEND result "-D_MDd")
        list(APPEND result -Xclang;--dependent-lib=msvcrtd)
      else()
        list(APPEND result "-D_MD")
        list(APPEND result -Xclang;--dependent-lib=msvcrt)
      endif()
    endif()

    # MSVC/clang-cl don't support -fno-pic or -fms-compatibility-version.
    if(NOT SWIFT_COMPILER_IS_MSVC_LIKE)
      list(APPEND result -fno-pic)
      list(APPEND result "-fms-compatibility-version=1900")
    endif()

    list(APPEND result "-DLLVM_ON_WIN32")
    list(APPEND result "-D_CRT_SECURE_NO_WARNINGS")
    list(APPEND result "-D_CRT_NONSTDC_NO_WARNINGS")
    if(NOT "${CMAKE_C_COMPILER_ID}" STREQUAL "MSVC")
      list(APPEND result "-D_CRT_USE_BUILTIN_OFFSETOF")
    endif()
    # TODO(compnerd) permit building for different families
    list(APPEND result "-D_CRT_USE_WINAPI_FAMILY_DESKTOP_APP")
    if("${CFLAGS_ARCH}" MATCHES arm)
      list(APPEND result "-D_ARM_WINAPI_PARTITION_DESKTOP_SDK_AVAILABLE")
    endif()
    # TODO(compnerd) handle /MT
    list(APPEND result "-D_DLL")
    # NOTE: We assume that we are using VS 2015 U2+
    list(APPEND result "-D_ENABLE_ATOMIC_ALIGNMENT_FIX")

    # msvcprt's std::function requires RTTI, but we do not want RTTI data.
    # Emulate /GR-.
    # TODO(compnerd) when moving up to VS 2017 15.3 and newer, we can disable
    # RTTI again
    if(SWIFT_COMPILER_IS_MSVC_LIKE)
      list(APPEND result /GR-)
    else()
      list(APPEND result -frtti)
      list(APPEND result -Xclang;-fno-rtti-data)
    endif()

    # NOTE: VS 2017 15.3 introduced this to disable the static components of
    # RTTI as well.  This requires a newer SDK though and we do not have
    # guarantees on the SDK version currently.
    list(APPEND result "-D_HAS_STATIC_RTTI=0")

    # NOTE(compnerd) workaround LLVM invoking `add_definitions(-D_DEBUG)` which
    # causes failures for the runtime library when cross-compiling due to
    # undefined symbols from the standard library.
    if(NOT CMAKE_BUILD_TYPE STREQUAL Debug)
      list(APPEND result "-U_DEBUG")
    endif()
  endif()

  if(CFLAGS_ENABLE_ASSERTIONS)
    list(APPEND result "-UNDEBUG")
  else()
    list(APPEND result "-DNDEBUG")
  endif()
  
  if(SWIFT_ENABLE_RUNTIME_FUNCTION_COUNTERS)
    list(APPEND result "-DSWIFT_ENABLE_RUNTIME_FUNCTION_COUNTERS")
  endif()

  if(CFLAGS_ANALYZE_CODE_COVERAGE)
    list(APPEND result "-fprofile-instr-generate"
                       "-fcoverage-mapping")
  endif()

  if("${CFLAGS_SDK}" STREQUAL "ANDROID")
    swift_android_libcxx_include_paths(CFLAGS_CXX_INCLUDES)
    swift_android_include_for_arch("${CFLAGS_ARCH}" "${CFLAGS_ARCH}_INCLUDE")
    foreach(path IN LISTS CFLAGS_CXX_INCLUDES ${CFLAGS_ARCH}_INCLUDE)
      list(APPEND result "\"${CMAKE_INCLUDE_FLAG_C}${path}\"")
    endforeach()
    list(APPEND result "-D__ANDROID_API__=${SWIFT_ANDROID_API_LEVEL}")
  elseif(CFLAGS_SDK STREQUAL WINDOWS)
    swift_windows_include_for_arch(${CFLAGS_ARCH} ${CFLAGS_ARCH}_INCLUDE)
    foreach(path ${${CFLAGS_ARCH}_INCLUDE})
      list(APPEND result "\"${CMAKE_INCLUDE_FLAG_C}${path}\"")
    endforeach()
  endif()

  set("${CFLAGS_RESULT_VAR_NAME}" "${result}" PARENT_SCOPE)
endfunction()

function(_add_variant_swift_compile_flags
    sdk arch build_type enable_assertions result_var_name)
  set(result ${${result_var_name}})

  # On Windows, we don't set SWIFT_SDK_WINDOWS_PATH_ARCH_{ARCH}_PATH, so don't include it.
  # On Android the sdk is split to two different paths for includes and libs, so these
  # need to be set manually.
  if (NOT "${sdk}" STREQUAL "WINDOWS" AND NOT "${sdk}" STREQUAL "ANDROID")
    list(APPEND result "-sdk" "${SWIFT_SDK_${sdk}_ARCH_${arch}_PATH}")
  endif()

  is_darwin_based_sdk("${sdk}" IS_DARWIN)
  if(IS_DARWIN)
    list(APPEND result
        "-target" "${SWIFT_SDK_${sdk}_ARCH_${arch}_TRIPLE}${SWIFT_SDK_${sdk}_DEPLOYMENT_VERSION}")
  else()
    list(APPEND result
        "-target" "${SWIFT_SDK_${sdk}_ARCH_${arch}_TRIPLE}")
  endif()

  if("${sdk}" STREQUAL "ANDROID")
    swift_android_include_for_arch(${arch} ${arch}_swift_include)
    foreach(path IN LISTS ${arch}_swift_include)
      list(APPEND result "\"${CMAKE_INCLUDE_FLAG_C}${path}\"")
    endforeach()
  endif()

  if(NOT BUILD_STANDALONE)
    list(APPEND result "-resource-dir" "${SWIFTLIB_DIR}")
  endif()

  if(IS_DARWIN)
    list(APPEND result
      "-F" "${SWIFT_SDK_${sdk}_ARCH_${arch}_PATH}/../../../Developer/Library/Frameworks")
  endif()

  is_build_type_optimized("${build_type}" optimized)
  if(optimized)
    list(APPEND result "-O")
  else()
    list(APPEND result "-Onone")
  endif()

  is_build_type_with_debuginfo("${build_type}" debuginfo)
  if(debuginfo)
    list(APPEND result "-g")
  endif()

  if(enable_assertions)
    list(APPEND result "-D" "INTERNAL_CHECKS_ENABLED")
  endif()

  if(SWIFT_ENABLE_RUNTIME_FUNCTION_COUNTERS)
    list(APPEND result "-D" "SWIFT_ENABLE_RUNTIME_FUNCTION_COUNTERS")
  endif()

  set("${result_var_name}" "${result}" PARENT_SCOPE)
endfunction()

function(_add_variant_link_flags)
  set(oneValueArgs SDK ARCH BUILD_TYPE ENABLE_ASSERTIONS ANALYZE_CODE_COVERAGE
  DEPLOYMENT_VERSION_OSX DEPLOYMENT_VERSION_IOS DEPLOYMENT_VERSION_TVOS DEPLOYMENT_VERSION_WATCHOS
  RESULT_VAR_NAME ENABLE_LTO LTO_OBJECT_NAME LINK_LIBRARIES_VAR_NAME LIBRARY_SEARCH_DIRECTORIES_VAR_NAME)
  cmake_parse_arguments(LFLAGS
    ""
    "${oneValueArgs}"
    ""
    ${ARGN})

  precondition(LFLAGS_SDK MESSAGE "Should specify an SDK")
  precondition(LFLAGS_ARCH MESSAGE "Should specify an architecture")

  set(result ${${LFLAGS_RESULT_VAR_NAME}})
  set(link_libraries ${${LFLAGS_LINK_LIBRARIES_VAR_NAME}})
  set(library_search_directories ${${LFLAGS_LIBRARY_SEARCH_DIRECTORIES_VAR_NAME}})

  _add_variant_c_compile_link_flags(
    SDK "${LFLAGS_SDK}"
    ARCH "${LFLAGS_ARCH}"
    BUILD_TYPE "${LFLAGS_BUILD_TYPE}"
    ENABLE_ASSERTIONS "${LFLAGS_ENABLE_ASSERTIONS}"
    ENABLE_LTO "${LFLAGS_ENABLE_LTO}"
    ANALYZE_CODE_COVERAGE "${LFLAGS_ANALYZE_CODE_COVERAGE}"
    DEPLOYMENT_VERSION_OSX "${LFLAGS_DEPLOYMENT_VERSION_OSX}"
    DEPLOYMENT_VERSION_IOS "${LFLAGS_DEPLOYMENT_VERSION_IOS}"
    DEPLOYMENT_VERSION_TVOS "${LFLAGS_DEPLOYMENT_VERSION_TVOS}"
    DEPLOYMENT_VERSION_WATCHOS "${LFLAGS_DEPLOYMENT_VERSION_WATCHOS}"
    RESULT_VAR_NAME result)

  if("${LFLAGS_SDK}" STREQUAL "LINUX")
    list(APPEND link_libraries "pthread" "atomic" "dl")
  elseif("${LFLAGS_SDK}" STREQUAL "FREEBSD")
    list(APPEND link_libraries "pthread")
  elseif("${LFLAGS_SDK}" STREQUAL "CYGWIN")
    # No extra libraries required.
  elseif("${LFLAGS_SDK}" STREQUAL "WINDOWS")
    # We don't need to add -nostdlib using MSVC or clang-cl, as MSVC and clang-cl rely on auto-linking entirely.
    if(NOT SWIFT_COMPILER_IS_MSVC_LIKE)
      # NOTE: we do not use "/MD" or "/MDd" and select the runtime via linker
      # options. This causes conflicts.
      list(APPEND result "-nostdlib")
    endif()
    swift_windows_lib_for_arch(${LFLAGS_ARCH} ${LFLAGS_ARCH}_LIB)
    list(APPEND library_search_directories ${${LFLAGS_ARCH}_LIB})

    # NOTE(compnerd) workaround incorrectly extensioned import libraries from
    # the Windows SDK on case sensitive file systems.
    list(APPEND library_search_directories
         ${CMAKE_BINARY_DIR}/winsdk_lib_${LFLAGS_ARCH}_symlinks)
  elseif("${LFLAGS_SDK}" STREQUAL "HAIKU")
    list(APPEND link_libraries "bsd" "atomic")
    list(APPEND result "-Wl,-Bsymbolic")
  elseif("${LFLAGS_SDK}" STREQUAL "ANDROID")
    list(APPEND link_libraries "dl" "log" "atomic" "icudataswift" "icui18nswift" "icuucswift")
    # We provide our own C++ below, so we ask the linker not to do it. However,
    # we need to add the math library, which is linked implicitly by libc++.
    list(APPEND result "-nostdlib++" "-lm")
    if("${LFLAGS_ARCH}" MATCHES armv7)
      set(android_libcxx_path "${SWIFT_ANDROID_NDK_PATH}/sources/cxx-stl/llvm-libc++/libs/armeabi-v7a")
    elseif("${LFLAGS_ARCH}" MATCHES aarch64)
      set(android_libcxx_path "${SWIFT_ANDROID_NDK_PATH}/sources/cxx-stl/llvm-libc++/libs/arm64-v8a")
    else()
      message(SEND_ERROR "unknown architecture (${LFLAGS_ARCH}) for android")
    endif()
    list(APPEND link_libraries "${android_libcxx_path}/libc++abi.a")
    list(APPEND link_libraries "${android_libcxx_path}/libc++_shared.so")
    swift_android_lib_for_arch(${LFLAGS_ARCH} ${LFLAGS_ARCH}_LIB)
    foreach(path IN LISTS ${LFLAGS_ARCH}_LIB)
      list(APPEND library_search_directories ${path})
    endforeach()
  else()
    # If lto is enabled, we need to add the object path flag so that the LTO code
    # generator leaves the intermediate object file in a place where it will not
    # be touched. The reason why this must be done is that on OS X, debug info is
    # left in object files. So if the object file is removed when we go to
    # generate a dsym, the debug info is gone.
    if (LFLAGS_ENABLE_LTO)
      precondition(LFLAGS_LTO_OBJECT_NAME
        MESSAGE "Should specify a unique name for the lto object")
      set(lto_object_dir ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR})
      set(lto_object ${lto_object_dir}/${LFLAGS_LTO_OBJECT_NAME}-lto.o)
        list(APPEND result "-Wl,-object_path_lto,${lto_object}")
      endif()
  endif()

  if(NOT "${SWIFT_${LFLAGS_SDK}_${LFLAGS_ARCH}_ICU_UC}" STREQUAL "")
    get_filename_component(SWIFT_${LFLAGS_SDK}_${LFLAGS_ARCH}_ICU_UC_LIBDIR
      "${SWIFT_${LFLAGS_SDK}_${LFLAGS_ARCH}_ICU_UC}" DIRECTORY)
    list(APPEND library_search_directories "${SWIFT_${LFLAGS_SDK}_${LFLAGS_ARCH}_ICU_UC_LIBDIR}")
  endif()
  if(NOT "${SWIFT_${LFLAGS_SDK}_${LFLAGS_ARCH}_ICU_I18N}" STREQUAL "")
    get_filename_component(SWIFT_${LFLAGS_SDK}_${LFLAGS_ARCH}_ICU_I18N_LIBDIR
      "${SWIFT_${LFLAGS_SDK}_${LFLAGS_ARCH}_ICU_I18N}" DIRECTORY)
    list(APPEND library_search_directories "${SWIFT_${LFLAGS_SDK}_${LFLAGS_ARCH}_ICU_I18N_LIBDIR}")
  endif()

  if(NOT SWIFT_COMPILER_IS_MSVC_LIKE)
    # FIXME: On Apple platforms, find_program needs to look for "ld64.lld"
    find_program(LDLLD_PATH "ld.lld")
    if((SWIFT_ENABLE_LLD_LINKER AND LDLLD_PATH AND NOT APPLE) OR
       ("${LFLAGS_SDK}" STREQUAL "WINDOWS" AND
        NOT "${CMAKE_SYSTEM_NAME}" STREQUAL "WINDOWS"))
      list(APPEND result "-fuse-ld=lld")
    elseif(SWIFT_ENABLE_GOLD_LINKER AND
       "${SWIFT_SDK_${LFLAGS_SDK}_OBJECT_FORMAT}" STREQUAL "ELF")
      list(APPEND result "-fuse-ld=gold")
    endif()
  endif()

  # Enable dead stripping. Portions of this logic were copied from llvm's
  # `add_link_opts` function (which, perhaps, should have been used here in the
  # first place, but at this point it's hard to say whether that's feasible).
  #
  # TODO: Evaluate/enable -f{function,data}-sections --gc-sections for bfd,
  # gold, and lld.
  if(NOT CMAKE_BUILD_TYPE STREQUAL Debug)
    if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
      # See rdar://48283130: This gives 6MB+ size reductions for swift and
      # SourceKitService, and much larger size reductions for sil-opt etc.
      list(APPEND result "-Wl,-dead_strip")
    endif()
  endif()

  set("${LFLAGS_RESULT_VAR_NAME}" "${result}" PARENT_SCOPE)
  set("${LFLAGS_LINK_LIBRARIES_VAR_NAME}" "${link_libraries}" PARENT_SCOPE)
  set("${LFLAGS_LIBRARY_SEARCH_DIRECTORIES_VAR_NAME}" "${library_search_directories}" PARENT_SCOPE)
endfunction()

# Look up extra flags for a module that matches a regexp.
function(_add_extra_swift_flags_for_module module_name result_var_name)
  set(result_list)
  list(LENGTH SWIFT_EXPERIMENTAL_EXTRA_REGEXP_FLAGS listlen)
  if (${listlen} GREATER 0)
    math(EXPR listlen "${listlen}-1")
    foreach(i RANGE 0 ${listlen} 2)
      list(GET SWIFT_EXPERIMENTAL_EXTRA_REGEXP_FLAGS ${i} regex)
      if (module_name MATCHES "${regex}")
        math(EXPR ip1 "${i}+1")
        list(GET SWIFT_EXPERIMENTAL_EXTRA_REGEXP_FLAGS ${ip1} flags)
        list(APPEND result_list ${flags})
        message(STATUS "Matched '${regex}' to module '${module_name}'. Compiling ${module_name} with special flags: ${flags}")
      endif()
    endforeach()
  endif()
  list(LENGTH SWIFT_EXPERIMENTAL_EXTRA_NEGATIVE_REGEXP_FLAGS listlen)
  if (${listlen} GREATER 0)
    math(EXPR listlen "${listlen}-1")
    foreach(i RANGE 0 ${listlen} 2)
      list(GET SWIFT_EXPERIMENTAL_EXTRA_NEGATIVE_REGEXP_FLAGS ${i} regex)
      if (NOT module_name MATCHES "${regex}")
        math(EXPR ip1 "${i}+1")
        list(GET SWIFT_EXPERIMENTAL_EXTRA_NEGATIVE_REGEXP_FLAGS ${ip1} flags)
        list(APPEND result_list ${flags})
        message(STATUS "Matched NEGATIVE '${regex}' to module '${module_name}'. Compiling ${module_name} with special flags: ${flags}")
      endif()
    endforeach()
  endif()
  set("${result_var_name}" ${result_list} PARENT_SCOPE)
endfunction()

# Add a universal binary target created from the output of the given
# set of targets by running 'lipo'.
#
# Usage:
#   _add_swift_lipo_target(
#     sdk                 # The name of the SDK the target was created for.
#                         # Examples include "OSX", "IOS", "ANDROID", etc.
#     target              # The name of the target to create
#     output              # The file to be created by this target
#     source_targets...   # The source targets whose outputs will be
#                         # lipo'd into the output.
#   )
function(_add_swift_lipo_target)
  cmake_parse_arguments(
    LIPO                # prefix
    "CODESIGN"          # options
    "SDK;TARGET;OUTPUT" # single-value args
    ""                  # multi-value args
    ${ARGN})

  precondition(LIPO_SDK MESSAGE "sdk is required")
  precondition(LIPO_TARGET MESSAGE "target is required")
  precondition(LIPO_OUTPUT MESSAGE "output is required")
  precondition(LIPO_UNPARSED_ARGUMENTS MESSAGE "one or more inputs are required")

  set(source_targets ${LIPO_UNPARSED_ARGUMENTS})

  # Gather the source binaries.
  set(source_binaries)
  foreach(source_target ${source_targets})
    list(APPEND source_binaries $<TARGET_FILE:${source_target}>)
  endforeach()

  if(${LIPO_SDK} IN_LIST SWIFT_APPLE_PLATFORMS)
    if(LIPO_CODESIGN)
      set(codesign_command COMMAND "codesign" "-f" "-s" "-" "${LIPO_OUTPUT}")
    endif()
    # Use lipo to create the final binary.
    add_custom_command_target(unused_var
        COMMAND "${SWIFT_LIPO}" "-create" "-output" "${LIPO_OUTPUT}" ${source_binaries}
        ${codesign_command}
        CUSTOM_TARGET_NAME "${LIPO_TARGET}"
        OUTPUT "${LIPO_OUTPUT}"
        DEPENDS ${source_targets})
  else()
    # We don't know how to create fat binaries for other platforms.
    add_custom_command_target(unused_var
        COMMAND "${CMAKE_COMMAND}" "-E" "copy" "${source_binaries}" "${LIPO_OUTPUT}"
        CUSTOM_TARGET_NAME "${LIPO_TARGET}"
        OUTPUT "${LIPO_OUTPUT}"
        DEPENDS ${source_targets})
  endif()
endfunction()

function(swift_target_link_search_directories target directories)
  set(STLD_FLAGS "")
  foreach(directory ${directories})
    set(STLD_FLAGS "${STLD_FLAGS} \"${CMAKE_LIBRARY_PATH_FLAG}${directory}\"")
  endforeach()
  set_property(TARGET ${target} APPEND_STRING PROPERTY LINK_FLAGS ${STLD_FLAGS})
endfunction()

# Add a single variant of a new Swift library.
#
# Usage:
#   _add_swift_library_single(
#     target
#     name
#     [MODULE_TARGET]
#     [SHARED]
#     [STATIC]
#     [SDK sdk]
#     [ARCHITECTURE architecture]
#     [DEPENDS dep1 ...]
#     [LINK_LIBRARIES dep1 ...]
#     [FRAMEWORK_DEPENDS dep1 ...]
#     [FRAMEWORK_DEPENDS_WEAK dep1 ...]
#     [LLVM_COMPONENT_DEPENDS comp1 ...]
#     [C_COMPILE_FLAGS flag1...]
#     [SWIFT_COMPILE_FLAGS flag1...]
#     [LINK_FLAGS flag1...]
#     [FILE_DEPENDS target1 ...]
#     [DONT_EMBED_BITCODE]
#     [IS_STDLIB]
#     [FORCE_BUILD_OPTIMIZED]
#     [IS_STDLIB_CORE]
#     [IS_SDK_OVERLAY]
#     INSTALL_IN_COMPONENT comp
#     source1 [source2 source3 ...])
#
# target
#   Name of the target (e.g., swiftParse-IOS-armv7).
#
# name
#   Name of the library (e.g., swiftParse).
#
# MODULE_TARGET
#   Name of the module target (e.g., swiftParse-swiftmodule-IOS-armv7).
#
# SHARED
#   Build a shared library.
#
# STATIC
#   Build a static library.
#
# SDK sdk
#   SDK to build for.
#
# ARCHITECTURE
#   Architecture to build for.
#
# DEPENDS
#   Targets that this library depends on.
#
# LINK_LIBRARIES
#   Libraries this library depends on.
#
# FRAMEWORK_DEPENDS
#   System frameworks this library depends on.
#
# FRAMEWORK_DEPENDS_WEAK
#   System frameworks this library depends on that should be weakly-linked.
#
# LLVM_COMPONENT_DEPENDS
#   LLVM components this library depends on.
#
# C_COMPILE_FLAGS
#   Extra compile flags (C, C++, ObjC).
#
# SWIFT_COMPILE_FLAGS
#   Extra compile flags (Swift).
#
# LINK_FLAGS
#   Extra linker flags.
#
# FILE_DEPENDS
#   Additional files this library depends on.
#
# DONT_EMBED_BITCODE
#   Don't embed LLVM bitcode in this target, even if it is enabled globally.
#
# IS_STDLIB
#   Install library dylib and swift module files to lib/swift.
#
# IS_STDLIB_CORE
#   Compile as the standard library core.
#
# IS_SDK_OVERLAY
#   Treat the library as a part of the Swift SDK overlay.
#
# INSTALL_IN_COMPONENT comp
#   The Swift installation component that this library belongs to.
#
# source1 ...
#   Sources to add into this library
function(_add_swift_library_single target name)
  set(SWIFTLIB_SINGLE_options
        DONT_EMBED_BITCODE
        FORCE_BUILD_OPTIMIZED
        IS_SDK_OVERLAY
        IS_STDLIB
        IS_STDLIB_CORE
        NOSWIFTRT
        OBJECT_LIBRARY
        SHARED
        STATIC
        TARGET_LIBRARY)
  set(SWIFTLIB_SINGLE_single_parameter_options
        ARCHITECTURE
        DEPLOYMENT_VERSION_IOS
        DEPLOYMENT_VERSION_OSX
        DEPLOYMENT_VERSION_TVOS
        DEPLOYMENT_VERSION_WATCHOS
        INSTALL_IN_COMPONENT
        MODULE_TARGET
        SDK)
  set(SWIFTLIB_SINGLE_multiple_parameter_options
        C_COMPILE_FLAGS
        DEPENDS
        FILE_DEPENDS
        FRAMEWORK_DEPENDS
        FRAMEWORK_DEPENDS_WEAK
        GYB_SOURCES
        INCORPORATE_OBJECT_LIBRARIES
        INCORPORATE_OBJECT_LIBRARIES_SHARED_ONLY
        INTERFACE_LINK_LIBRARIES
        LINK_FLAGS
        LINK_LIBRARIES
        LLVM_COMPONENT_DEPENDS
        PRIVATE_LINK_LIBRARIES
        SWIFT_COMPILE_FLAGS)

  cmake_parse_arguments(SWIFTLIB_SINGLE
                        "${SWIFTLIB_SINGLE_options}"
                        "${SWIFTLIB_SINGLE_single_parameter_options}"
                        "${SWIFTLIB_SINGLE_multiple_parameter_options}"
                        ${ARGN})
  set(SWIFTLIB_SINGLE_SOURCES ${SWIFTLIB_SINGLE_UNPARSED_ARGUMENTS})

  translate_flags(SWIFTLIB_SINGLE "${SWIFTLIB_SINGLE_options}")

  # Check arguments.
  precondition(SWIFTLIB_SINGLE_SDK MESSAGE "Should specify an SDK")
  precondition(SWIFTLIB_SINGLE_ARCHITECTURE MESSAGE "Should specify an architecture")
  precondition(SWIFTLIB_SINGLE_INSTALL_IN_COMPONENT MESSAGE "INSTALL_IN_COMPONENT is required")

  if(NOT SWIFTLIB_SINGLE_SHARED AND
     NOT SWIFTLIB_SINGLE_STATIC AND
     NOT SWIFTLIB_SINGLE_OBJECT_LIBRARY)
    message(FATAL_ERROR
        "Either SHARED, STATIC, or OBJECT_LIBRARY must be specified")
  endif()

  # Determine the subdirectory where this library will be installed.
  set(SWIFTLIB_SINGLE_SUBDIR
      "${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}/${SWIFTLIB_SINGLE_ARCHITECTURE}")

  # Include LLVM Bitcode slices for iOS, Watch OS, and Apple TV OS device libraries.
  set(embed_bitcode_arg)
  if(SWIFT_EMBED_BITCODE_SECTION AND NOT SWIFTLIB_SINGLE_DONT_EMBED_BITCODE)
    if("${SWIFTLIB_SINGLE_SDK}" STREQUAL "IOS" OR "${SWIFTLIB_SINGLE_SDK}" STREQUAL "TVOS" OR "${SWIFTLIB_SINGLE_SDK}" STREQUAL "WATCHOS")
      list(APPEND SWIFTLIB_SINGLE_C_COMPILE_FLAGS "-fembed-bitcode")
      list(APPEND SWIFTLIB_SINGLE_LINK_FLAGS "-Xlinker" "-bitcode_bundle" "-Xlinker" "-lto_library" "-Xlinker" "${LLVM_LIBRARY_DIR}/libLTO.dylib")
      # If we are asked to hide symbols, pass the obfuscation flag to libLTO.
      if (SWIFT_EMBED_BITCODE_SECTION_HIDE_SYMBOLS)
        list(APPEND SWIFTLIB_SINGLE_LINK_FLAGS "-Xlinker" "-bitcode_hide_symbols")
      endif()
      set(embed_bitcode_arg EMBED_BITCODE)
    endif()
  endif()

  if(${SWIFTLIB_SINGLE_SDK} IN_LIST SWIFT_APPLE_PLATFORMS)
    list(APPEND SWIFTLIB_SINGLE_LINK_FLAGS "-Xlinker" "-compatibility_version" "-Xlinker" "1")
    if (SWIFT_COMPILER_VERSION)
      list(APPEND SWIFTLIB_SINGLE_LINK_FLAGS "-Xlinker" "-current_version" "-Xlinker" "${SWIFT_COMPILER_VERSION}" )
    endif()
  endif()

  if(XCODE)
    string(REGEX MATCHALL "/[^/]+" split_path ${CMAKE_CURRENT_SOURCE_DIR})
    list(GET split_path -1 dir)
    file(GLOB_RECURSE SWIFTLIB_SINGLE_HEADERS
      ${SWIFT_SOURCE_DIR}/include/swift${dir}/*.h
      ${SWIFT_SOURCE_DIR}/include/swift${dir}/*.def
      ${CMAKE_CURRENT_SOURCE_DIR}/*.def)

    file(GLOB_RECURSE SWIFTLIB_SINGLE_TDS
      ${SWIFT_SOURCE_DIR}/include/swift${dir}/*.td)

    set_source_files_properties(${SWIFTLIB_SINGLE_HEADERS} ${SWIFTLIB_SINGLE_TDS}
      PROPERTIES
      HEADER_FILE_ONLY true)
    source_group("TableGen descriptions" FILES ${SWIFTLIB_SINGLE_TDS})

    set(SWIFTLIB_SINGLE_SOURCES ${SWIFTLIB_SINGLE_SOURCES} ${SWIFTLIB_SINGLE_HEADERS} ${SWIFTLIB_SINGLE_TDS})
  endif()

  if(MODULE)
    set(libkind MODULE)
  elseif(SWIFTLIB_SINGLE_OBJECT_LIBRARY)
    set(libkind OBJECT)
  # If both SHARED and STATIC are specified, we add the SHARED library first.
  # The STATIC library is handled further below.
  elseif(SWIFTLIB_SINGLE_SHARED)
    set(libkind SHARED)
  elseif(SWIFTLIB_SINGLE_STATIC)
    set(libkind STATIC)
  else()
    message(FATAL_ERROR
        "Either SHARED, STATIC, or OBJECT_LIBRARY must be specified")
  endif()

  if(SWIFTLIB_SINGLE_GYB_SOURCES)
    handle_gyb_sources(
        gyb_dependency_targets
        SWIFTLIB_SINGLE_GYB_SOURCES
        "${SWIFTLIB_SINGLE_ARCHITECTURE}")
    set(SWIFTLIB_SINGLE_SOURCES ${SWIFTLIB_SINGLE_SOURCES}
      ${SWIFTLIB_SINGLE_GYB_SOURCES})
  endif()

  # Remove the "swift" prefix from the name to determine the module name.
  if(SWIFTLIB_IS_STDLIB_CORE)
    set(module_name "Swift")
  else()
    string(REPLACE swift "" module_name "${name}")
  endif()

  if("${SWIFTLIB_SINGLE_SDK}" STREQUAL "WINDOWS")
    if(NOT "${CMAKE_C_COMPILER_ID}" STREQUAL "MSVC")
      swift_windows_generate_sdk_vfs_overlay(SWIFTLIB_SINGLE_VFS_OVERLAY_FLAGS)
      foreach(flag ${SWIFTLIB_SINGLE_VFS_OVERLAY_FLAGS})
        list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS -Xcc;${flag})
        list(APPEND SWIFTLIB_SINGLE_C_COMPILE_FLAGS ${flag})
      endforeach()
    endif()
    swift_windows_include_for_arch(${SWIFTLIB_SINGLE_ARCHITECTURE} SWIFTLIB_INCLUDE)
    foreach(directory ${SWIFTLIB_INCLUDE})
      list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS -Xcc;-isystem;-Xcc;${directory})
    endforeach()
    if("${SWIFTLIB_SINGLE_ARCHITECTURE}" MATCHES arm)
      list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS -Xcc;-D_ARM_WINAPI_PARTITION_DESKTOP_SDK_AVAILABLE)
    endif()
    list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS -Xfrontend;-autolink-library;-Xfrontend;oldnames)
    # TODO(compnerd) handle /MT and /MTd
    if(CMAKE_BUILD_TYPE MATCHES Debug)
      list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS -Xfrontend;-autolink-library;-Xfrontend;msvcrtd)
    else()
      list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS -Xfrontend;-autolink-library;-Xfrontend;msvcrt)
    endif()
  endif()

  # FIXME: don't actually depend on the libraries in SWIFTLIB_SINGLE_LINK_LIBRARIES,
  # just any swiftmodule files that are associated with them.
  handle_swift_sources(
      swift_object_dependency_target
      swift_module_dependency_target
      swift_sib_dependency_target
      swift_sibopt_dependency_target
      swift_sibgen_dependency_target
      SWIFTLIB_SINGLE_SOURCES
      SWIFTLIB_SINGLE_EXTERNAL_SOURCES ${name}
      DEPENDS
        ${gyb_dependency_targets}
        ${SWIFTLIB_SINGLE_DEPENDS}
        ${SWIFTLIB_SINGLE_FILE_DEPENDS}
        ${SWIFTLIB_SINGLE_LINK_LIBRARIES}
        ${SWIFTLIB_SINGLE_INTERFACE_LINK_LIBRARIES}
      SDK ${SWIFTLIB_SINGLE_SDK}
      ARCHITECTURE ${SWIFTLIB_SINGLE_ARCHITECTURE}
      MODULE_NAME ${module_name}
      COMPILE_FLAGS ${SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS}
      ${SWIFTLIB_SINGLE_IS_STDLIB_keyword}
      ${SWIFTLIB_SINGLE_IS_STDLIB_CORE_keyword}
      ${SWIFTLIB_SINGLE_IS_SDK_OVERLAY_keyword}
      ${embed_bitcode_arg}
      INSTALL_IN_COMPONENT "${SWIFTLIB_SINGLE_INSTALL_IN_COMPONENT}")
  add_swift_source_group("${SWIFTLIB_SINGLE_EXTERNAL_SOURCES}")

  # If there were any swift sources, then a .swiftmodule may have been created.
  # If that is the case, then add a target which is an alias of the module files.
  set(VARIANT_SUFFIX "-${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}-${SWIFTLIB_SINGLE_ARCHITECTURE}")
  if(NOT "${SWIFTLIB_SINGLE_MODULE_TARGET}" STREQUAL "" AND NOT "${swift_module_dependency_target}" STREQUAL "")
    add_custom_target("${SWIFTLIB_SINGLE_MODULE_TARGET}"
      DEPENDS ${swift_module_dependency_target})
    set_target_properties("${SWIFTLIB_SINGLE_MODULE_TARGET}" PROPERTIES
      FOLDER "Swift libraries/Modules")
  endif()

  # For standalone overlay builds to work
  if(NOT BUILD_STANDALONE)
    if (EXISTS swift_sib_dependency_target AND NOT "${swift_sib_dependency_target}" STREQUAL "")
      add_dependencies(swift-stdlib${VARIANT_SUFFIX}-sib ${swift_sib_dependency_target})
    endif()

    if (EXISTS swift_sibopt_dependency_target AND NOT "${swift_sibopt_dependency_target}" STREQUAL "")
      add_dependencies(swift-stdlib${VARIANT_SUFFIX}-sibopt ${swift_sibopt_dependency_target})
    endif()

    if (EXISTS swift_sibgen_dependency_target AND NOT "${swift_sibgen_dependency_target}" STREQUAL "")
      add_dependencies(swift-stdlib${VARIANT_SUFFIX}-sibgen ${swift_sibgen_dependency_target})
    endif()
  endif()

  set(SWIFTLIB_INCORPORATED_OBJECT_LIBRARIES_EXPRESSIONS)
  foreach(object_library ${SWIFTLIB_SINGLE_INCORPORATE_OBJECT_LIBRARIES})
    list(APPEND SWIFTLIB_INCORPORATED_OBJECT_LIBRARIES_EXPRESSIONS
        $<TARGET_OBJECTS:${object_library}${VARIANT_SUFFIX}>)
  endforeach()

  set(SWIFTLIB_INCORPORATED_OBJECT_LIBRARIES_EXPRESSIONS_SHARED_ONLY)
  foreach(object_library ${SWIFTLIB_SINGLE_INCORPORATE_OBJECT_LIBRARIES_SHARED_ONLY})
    list(APPEND SWIFTLIB_INCORPORATED_OBJECT_LIBRARIES_EXPRESSIONS_SHARED_ONLY
        $<TARGET_OBJECTS:${object_library}${VARIANT_SUFFIX}>)
  endforeach()

  set(SWIFTLIB_SINGLE_XCODE_WORKAROUND_SOURCES)
  if(XCODE AND SWIFTLIB_SINGLE_TARGET_LIBRARY)
    set(SWIFTLIB_SINGLE_XCODE_WORKAROUND_SOURCES
        # Note: the dummy.cpp source file provides no definitions. However,
        # it forces Xcode to properly link the static library.
        ${SWIFT_SOURCE_DIR}/cmake/dummy.cpp)
  endif()

  set(INCORPORATED_OBJECT_LIBRARIES_EXPRESSIONS ${SWIFTLIB_INCORPORATED_OBJECT_LIBRARIES_EXPRESSIONS})
  if(${libkind} STREQUAL "SHARED")
    list(APPEND INCORPORATED_OBJECT_LIBRARIES_EXPRESSIONS
         ${SWIFTLIB_INCORPORATED_OBJECT_LIBRARIES_EXPRESSIONS_SHARED_ONLY})
  endif()

  add_library("${target}" ${libkind}
              ${SWIFTLIB_SINGLE_SOURCES}
              ${SWIFTLIB_SINGLE_EXTERNAL_SOURCES}
              ${INCORPORATED_OBJECT_LIBRARIES_EXPRESSIONS}
              ${SWIFTLIB_SINGLE_XCODE_WORKAROUND_SOURCES})
  if(("${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_OBJECT_FORMAT}" STREQUAL "ELF" OR
      "${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_OBJECT_FORMAT}" STREQUAL "COFF") AND
     SWIFTLIB_TARGET_LIBRARY)
    if("${libkind}" STREQUAL "SHARED" AND NOT SWIFTLIB_SINGLE_NOSWIFTRT)
      # TODO(compnerd) switch to the generator expression when cmake is upgraded
      # to a version which supports it.
      # target_sources(${target}
      #                PRIVATE
      #                  $<TARGET_OBJECTS:swiftImageRegistrationObject${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_OBJECT_FORMAT}-${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}-${SWIFTLIB_SINGLE_ARCHITECTURE}>)
      if(SWIFTLIB_SINGLE_SDK STREQUAL WINDOWS)
        set(extension .obj)
      else()
        set(extension .o)
      endif()
      target_sources(${target}
                     PRIVATE
                       "${SWIFTLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR}/swiftrt${extension}")
      set_source_files_properties("${SWIFTLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR}/swiftrt${extension}"
                                  PROPERTIES
                                    GENERATED 1)
    endif()
  endif()
  _set_target_prefix_and_suffix("${target}" "${libkind}" "${SWIFTLIB_SINGLE_SDK}")

  if(SWIFTLIB_SINGLE_TARGET_LIBRARY)
    if(NOT "${SWIFT_${SWIFTLIB_SINGLE_SDK}_${SWIFTLIB_SINGLE_ARCHITECTURE}_ICU_UC_INCLUDE}" STREQUAL "" AND
       NOT "${SWIFT_${SWIFTLIB_SINGLE_SDK}_${SWIFTLIB_SINGLE_ARCHITECTURE}_ICU_UC_INCLUDE}" STREQUAL "/usr/include" AND
       NOT "${SWIFT_${SWIFTLIB_SINGLE_SDK}_${SWIFTLIB_SINGLE_ARCHITECTURE}_ICU_UC_INCLUDE}" STREQUAL "/usr/${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_ARCH_${SWIFTLIB_SINGLE_ARCHITECTURE}_TRIPLE}/include" AND
       NOT "${SWIFT_${SWIFTLIB_SINGLE_SDK}_${SWIFTLIB_SINGLE_ARCHITECTURE}_ICU_UC_INCLUDE}" STREQUAL "/usr/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_ARCH_${SWIFT_HOST_VARIANT_ARCH}_TRIPLE}/include")
     target_include_directories("${target}" SYSTEM PRIVATE "${SWIFT_${SWIFTLIB_SINGLE_SDK}_${SWIFTLIB_SINGLE_ARCHITECTURE}_ICU_UC_INCLUDE}")
    endif()
    if(NOT "${SWIFT_${SWIFTLIB_SINGLE_SDK}_${SWIFTLIB_SINGLE_ARCHITECTURE}_ICU_I18N_INCLUDE}" STREQUAL "" AND
       NOT "${SWIFT_${SWIFTLIB_SINGLE_SDK}_${SWIFTLIB_SINGLE_ARCHITECTURE}_ICU_I18N_INCLUDE}" STREQUAL "/usr/include" AND
       NOT "${SWIFT_${SWIFTLIB_SINGLE_SDK}_${SWIFTLIB_SINGLE_ARCHITECTURE}_ICU_I18N_INCLUDE}" STREQUAL "/usr/${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_ARCH_${SWIFTLIB_SINGLE_ARCHITECTURE}_TRIPLE}/include" AND
       NOT "${SWIFT_${SWIFTLIB_SINGLE_SDK}_${SWIFTLIB_SINGLE_ARCHITECTURE}_ICU_I18N_INCLUDE}" STREQUAL "/usr/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_ARCH_${SWIFT_HOST_VARIANT_ARCH}_TRIPLE}/include")
     target_include_directories("${target}" SYSTEM PRIVATE "${SWIFT_${SWIFTLIB_SINGLE_SDK}_${SWIFTLIB_SINGLE_ARCHITECTURE}_ICU_I18N_INCLUDE}")
    endif()
  endif()

  if("${SWIFTLIB_SINGLE_SDK}" STREQUAL "WINDOWS")
    swift_windows_include_for_arch(${SWIFTLIB_SINGLE_ARCHITECTURE} SWIFTLIB_INCLUDE)
    target_include_directories("${target}" SYSTEM PRIVATE ${SWIFTLIB_INCLUDE})
    set_target_properties(${target}
                          PROPERTIES
                            CXX_STANDARD 14)
  endif()

  if("${SWIFTLIB_SINGLE_SDK}" STREQUAL "WINDOWS" AND NOT "${CMAKE_SYSTEM_NAME}" STREQUAL "Windows")
    if("${libkind}" STREQUAL "SHARED")
      # Each dll has an associated .lib (import library); since we may be
      # building on a non-DLL platform (not windows), create an imported target
      # for the library which created implicitly by the dll.
      add_custom_command_target(${target}_IMPORT_LIBRARY
                                OUTPUT "${SWIFTLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR}/${name}.lib"
                                DEPENDS "${target}")
      add_library(${target}_IMPLIB SHARED IMPORTED GLOBAL)
      set_property(TARGET "${target}_IMPLIB" PROPERTY
          IMPORTED_LOCATION "${SWIFTLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR}/${name}.lib")
      add_dependencies(${target}_IMPLIB ${${target}_IMPORT_LIBRARY})
    endif()
    set_property(TARGET "${target}" PROPERTY NO_SONAME ON)
  endif()

  llvm_update_compile_flags(${target})

  set_output_directory(${target}
      BINARY_DIR ${SWIFT_RUNTIME_OUTPUT_INTDIR}
      LIBRARY_DIR ${SWIFT_LIBRARY_OUTPUT_INTDIR})

  if(MODULE)
    set_target_properties("${target}" PROPERTIES
        PREFIX ""
        SUFFIX ${LLVM_PLUGIN_EXT})
  endif()

  if(SWIFTLIB_SINGLE_TARGET_LIBRARY)
    # Install runtime libraries to lib/swift instead of lib. This works around
    # the fact that -isysroot prevents linking to libraries in the system
    # /usr/lib if Swift is installed in /usr.
    set_target_properties("${target}" PROPERTIES
      LIBRARY_OUTPUT_DIRECTORY ${SWIFTLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR}
      ARCHIVE_OUTPUT_DIRECTORY ${SWIFTLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR})

    foreach(config ${CMAKE_CONFIGURATION_TYPES})
      string(TOUPPER ${config} config_upper)
      escape_path_for_xcode("${config}" "${SWIFTLIB_DIR}" config_lib_dir)
      set_target_properties(${target} PROPERTIES
        LIBRARY_OUTPUT_DIRECTORY_${config_upper} ${config_lib_dir}/${SWIFTLIB_SINGLE_SUBDIR}
        ARCHIVE_OUTPUT_DIRECTORY_${config_upper} ${config_lib_dir}/${SWIFTLIB_SINGLE_SUBDIR})
    endforeach()
  endif()

  if(SWIFTLIB_SINGLE_SDK IN_LIST SWIFT_APPLE_PLATFORMS)
    set(install_name_dir "@rpath")

    if(SWIFTLIB_SINGLE_IS_STDLIB)
      set(install_name_dir "${SWIFT_DARWIN_STDLIB_INSTALL_NAME_DIR}")
    endif()

    # Always use @rpath for XCTest
    if(module_name STREQUAL "XCTest")
      set(install_name_dir "@rpath")
    endif()

    set_target_properties("${target}"
      PROPERTIES
      INSTALL_NAME_DIR "${install_name_dir}")
  elseif("${SWIFTLIB_SINGLE_SDK}" STREQUAL "LINUX" AND NOT "${SWIFTLIB_SINGLE_SDK}" STREQUAL "ANDROID")
    set_target_properties("${target}"
      PROPERTIES
      INSTALL_RPATH "$ORIGIN:/usr/lib/swift/linux")
  elseif("${SWIFTLIB_SINGLE_SDK}" STREQUAL "CYGWIN")
    set_target_properties("${target}"
      PROPERTIES
      INSTALL_RPATH "$ORIGIN:/usr/lib/swift/cygwin")
  endif()

  set_target_properties("${target}" PROPERTIES BUILD_WITH_INSTALL_RPATH YES)
  set_target_properties("${target}" PROPERTIES FOLDER "Swift libraries")

  # Configure the static library target.
  # Set compile and link flags for the non-static target.
  # Do these LAST.
  set(target_static)
  if(SWIFTLIB_SINGLE_IS_STDLIB AND SWIFTLIB_SINGLE_STATIC)
    set(target_static "${target}-static")

    # We have already compiled Swift sources.  Link everything into a static
    # library.
    add_library(${target_static} STATIC
        ${SWIFTLIB_SINGLE_SOURCES}
        ${SWIFTLIB_INCORPORATED_OBJECT_LIBRARIES_EXPRESSIONS}
        ${SWIFTLIB_SINGLE_XCODE_WORKAROUND_SOURCES})

    set_output_directory(${target_static}
        BINARY_DIR ${SWIFT_RUNTIME_OUTPUT_INTDIR}
        LIBRARY_DIR ${SWIFT_LIBRARY_OUTPUT_INTDIR})

    foreach(config ${CMAKE_CONFIGURATION_TYPES})
      string(TOUPPER ${config} config_upper)
      escape_path_for_xcode(
          "${config}" "${SWIFTSTATICLIB_DIR}" config_lib_dir)
      set_target_properties(${target_static} PROPERTIES
        LIBRARY_OUTPUT_DIRECTORY_${config_upper} ${config_lib_dir}/${SWIFTLIB_SINGLE_SUBDIR}
        ARCHIVE_OUTPUT_DIRECTORY_${config_upper} ${config_lib_dir}/${SWIFTLIB_SINGLE_SUBDIR})
    endforeach()

    set_target_properties(${target_static} PROPERTIES
      LIBRARY_OUTPUT_DIRECTORY ${SWIFTSTATICLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR}
      ARCHIVE_OUTPUT_DIRECTORY ${SWIFTSTATICLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR})
  endif()

  set_target_properties(${target}
      PROPERTIES
      # Library name (without the variant information)
      OUTPUT_NAME ${name})
  if(target_static)
    set_target_properties(${target_static}
        PROPERTIES
        OUTPUT_NAME ${name})
  endif()

  # Don't build standard libraries by default.  We will enable building
  # standard libraries that the user requested; the rest can be built on-demand.
  if(SWIFTLIB_SINGLE_TARGET_LIBRARY)
    foreach(t "${target}" ${target_static})
      set_target_properties(${t} PROPERTIES EXCLUDE_FROM_ALL TRUE)
    endforeach()
  endif()

  # Handle linking and dependencies.
  add_dependencies_multiple_targets(
      TARGETS "${target}" ${target_static}
      DEPENDS
        ${SWIFTLIB_SINGLE_DEPENDS}
        ${gyb_dependency_targets}
        "${swift_object_dependency_target}"
        "${swift_module_dependency_target}"
        ${LLVM_COMMON_DEPENDS})

  # HACK: On some systems or build directory setups, CMake will not find static
  # archives of Clang libraries in the Clang build directory, and it will pass
  # them as '-lclangFoo'.  Some other logic in CMake would reorder libraries
  # specified with this syntax, which breaks linking.
  set(prefixed_link_libraries)
  foreach(dep ${SWIFTLIB_SINGLE_LINK_LIBRARIES})
    if("${dep}" MATCHES "^clang")
      if("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "WINDOWS")
        set(dep "${LLVM_LIBRARY_OUTPUT_INTDIR}/${dep}.lib")
      else()
        set(dep "${LLVM_LIBRARY_OUTPUT_INTDIR}/lib${dep}.a")
      endif()
    endif()
    list(APPEND prefixed_link_libraries "${dep}")
  endforeach()
  set(SWIFTLIB_SINGLE_LINK_LIBRARIES "${prefixed_link_libraries}")

  if("${libkind}" STREQUAL "SHARED")
    target_link_libraries("${target}" PRIVATE ${SWIFTLIB_SINGLE_LINK_LIBRARIES})
  elseif("${libkind}" STREQUAL "OBJECT")
    precondition_list_empty(
        "${SWIFTLIB_SINGLE_LINK_LIBRARIES}"
        "OBJECT_LIBRARY may not link to anything")
  else()
    target_link_libraries("${target}" INTERFACE ${SWIFTLIB_SINGLE_LINK_LIBRARIES})
  endif()

  # Don't add the icucore target.
  set(SWIFTLIB_SINGLE_LINK_LIBRARIES_WITHOUT_ICU)
  foreach(item ${SWIFTLIB_SINGLE_LINK_LIBRARIES})
    if(NOT "${item}" STREQUAL "icucore")
      list(APPEND SWIFTLIB_SINGLE_LINK_LIBRARIES_WITHOUT_ICU "${item}")
    endif()
  endforeach()

  if(target_static)
    _list_add_string_suffix(
        "${SWIFTLIB_SINGLE_LINK_LIBRARIES_WITHOUT_ICU}"
        "-static"
        target_static_depends)
    # FIXME: should this be target_link_libraries?
    add_dependencies_multiple_targets(
        TARGETS "${target_static}"
        DEPENDS ${target_static_depends})
  endif()

  # Link against system frameworks.
  foreach(FRAMEWORK ${SWIFTLIB_SINGLE_FRAMEWORK_DEPENDS})
    foreach(t "${target}" ${target_static})
      target_link_libraries("${t}" PUBLIC "-framework ${FRAMEWORK}")
    endforeach()
  endforeach()
  foreach(FRAMEWORK ${SWIFTLIB_SINGLE_FRAMEWORK_DEPENDS_WEAK})
    foreach(t "${target}" ${target_static})
      target_link_libraries("${t}" PUBLIC "-weak_framework ${FRAMEWORK}")
    endforeach()
  endforeach()

  if(NOT SWIFTLIB_SINGLE_TARGET_LIBRARY)
    # Call llvm_config() only for libraries that are part of the compiler.
    swift_common_llvm_config("${target}" ${SWIFTLIB_SINGLE_LLVM_COMPONENT_DEPENDS})
  endif()

  # Collect compile and link flags for the static and non-static targets.
  # Don't set PROPERTY COMPILE_FLAGS or LINK_FLAGS directly.
  set(c_compile_flags ${SWIFTLIB_SINGLE_C_COMPILE_FLAGS})
  set(link_flags ${SWIFTLIB_SINGLE_LINK_FLAGS})

  set(library_search_subdir "${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}")
  set(library_search_directories
      "${SWIFTLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR}"
      "${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFTLIB_SINGLE_SUBDIR}"
      "${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}")

  # Add variant-specific flags.
  if(SWIFTLIB_SINGLE_TARGET_LIBRARY)
    set(build_type "${SWIFT_STDLIB_BUILD_TYPE}")
    set(enable_assertions "${SWIFT_STDLIB_ASSERTIONS}")
  else()
    set(build_type "${CMAKE_BUILD_TYPE}")
    set(enable_assertions "${LLVM_ENABLE_ASSERTIONS}")
    set(analyze_code_coverage "${SWIFT_ANALYZE_CODE_COVERAGE}")
  endif()

  if (NOT SWIFTLIB_SINGLE_TARGET_LIBRARY)
    set(lto_type "${SWIFT_TOOLS_ENABLE_LTO}")
  endif()

  _add_variant_c_compile_flags(
    SDK "${SWIFTLIB_SINGLE_SDK}"
    ARCH "${SWIFTLIB_SINGLE_ARCHITECTURE}"
    BUILD_TYPE "${build_type}"
    ENABLE_ASSERTIONS "${enable_assertions}"
    ANALYZE_CODE_COVERAGE "${analyze_code_coverage}"
    ENABLE_LTO "${lto_type}"
    DEPLOYMENT_VERSION_OSX "${SWIFTLIB_DEPLOYMENT_VERSION_OSX}"
    DEPLOYMENT_VERSION_IOS "${SWIFTLIB_DEPLOYMENT_VERSION_IOS}"
    DEPLOYMENT_VERSION_TVOS "${SWIFTLIB_DEPLOYMENT_VERSION_TVOS}"
    DEPLOYMENT_VERSION_WATCHOS "${SWIFTLIB_DEPLOYMENT_VERSION_WATCHOS}"
    "${SWIFTLIB_SINGLE_FORCE_BUILD_OPTIMIZED_keyword}"
    RESULT_VAR_NAME c_compile_flags
    )

  if(SWIFTLIB_IS_STDLIB)
    # We don't ever want to link against the ABI-breakage checking symbols
    # in the standard library, runtime, or overlays because they only rely
    # on the header parts of LLVM's ADT.
    list(APPEND c_compile_flags
      "-DLLVM_DISABLE_ABI_BREAKING_CHECKS_ENFORCING=1")
  endif()

  if(SWIFTLIB_SINGLE_SDK STREQUAL WINDOWS)
    if(libkind STREQUAL SHARED)
      list(APPEND c_compile_flags -D_WINDLL)
    endif()
  endif()
  _add_variant_link_flags(
    SDK "${SWIFTLIB_SINGLE_SDK}"
    ARCH "${SWIFTLIB_SINGLE_ARCHITECTURE}"
    BUILD_TYPE "${build_type}"
    ENABLE_ASSERTIONS "${enable_assertions}"
    ANALYZE_CODE_COVERAGE "${analyze_code_coverage}"
    ENABLE_LTO "${lto_type}"
    LTO_OBJECT_NAME "${target}-${SWIFTLIB_SINGLE_SDK}-${SWIFTLIB_SINGLE_ARCHITECTURE}"
    DEPLOYMENT_VERSION_OSX "${SWIFTLIB_DEPLOYMENT_VERSION_OSX}"
    DEPLOYMENT_VERSION_IOS "${SWIFTLIB_DEPLOYMENT_VERSION_IOS}"
    DEPLOYMENT_VERSION_TVOS "${SWIFTLIB_DEPLOYMENT_VERSION_TVOS}"
    DEPLOYMENT_VERSION_WATCHOS "${SWIFTLIB_DEPLOYMENT_VERSION_WATCHOS}"
    RESULT_VAR_NAME link_flags
    LINK_LIBRARIES_VAR_NAME link_libraries
    LIBRARY_SEARCH_DIRECTORIES_VAR_NAME library_search_directories
      )

  # Configure plist creation for OS X.
  set(PLIST_INFO_PLIST "Info.plist" CACHE STRING "Plist name")
  if("${SWIFTLIB_SINGLE_SDK}" IN_LIST SWIFT_APPLE_PLATFORMS AND SWIFTLIB_SINGLE_IS_STDLIB)
    set(PLIST_INFO_NAME ${name})
    set(PLIST_INFO_UTI "com.apple.dt.runtime.${name}")
    set(PLIST_INFO_VERSION "${SWIFT_VERSION}")
    if (SWIFT_COMPILER_VERSION)
      set(PLIST_INFO_BUILD_VERSION
        "${SWIFT_COMPILER_VERSION}")
    endif()

    set(PLIST_INFO_PLIST_OUT "${PLIST_INFO_PLIST}")
    list(APPEND link_flags
         "-Wl,-sectcreate,__TEXT,__info_plist,${CMAKE_CURRENT_BINARY_DIR}/${PLIST_INFO_PLIST_OUT}")
    configure_file(
        "${SWIFT_SOURCE_DIR}/stdlib/${PLIST_INFO_PLIST}.in"
        "${PLIST_INFO_PLIST_OUT}"
        @ONLY
        NEWLINE_STYLE UNIX)

    # If Application Extensions are enabled, pass the linker flag marking
    # the dylib as safe.
    if (CXX_SUPPORTS_FAPPLICATION_EXTENSION AND (NOT DISABLE_APPLICATION_EXTENSION))
      list(APPEND link_flags "-Wl,-application_extension")
    endif()

    set(PLIST_INFO_UTI)
    set(PLIST_INFO_NAME)
    set(PLIST_INFO_VERSION)
    set(PLIST_INFO_BUILD_VERSION)
  endif()

  # Convert variables to space-separated strings.
  _list_escape_for_shell("${c_compile_flags}" c_compile_flags)
  _list_escape_for_shell("${link_flags}" link_flags)

  # Set compilation and link flags.
  set_property(TARGET "${target}" APPEND_STRING PROPERTY
      COMPILE_FLAGS " ${c_compile_flags}")
  set_property(TARGET "${target}" APPEND_STRING PROPERTY
      LINK_FLAGS " ${link_flags}")
  set_property(TARGET "${target}" APPEND PROPERTY LINK_LIBRARIES ${link_libraries})
  swift_target_link_search_directories("${target}" "${library_search_directories}")

  # Adjust the linked libraries for windows targets.  On Windows, the link is
  # performed against the import library, and the runtime uses the dll.  Not
  # doing so will result in incorrect symbol resolution and linkage.  We created
  # import library targets when the library was added.  Use that to adjust the
  # link libraries.
  if(SWIFTLIB_SINGLE_SDK STREQUAL WINDOWS AND NOT CMAKE_HOST_SYSTEM_NAME STREQUAL Windows)
    foreach(library_list LINK_LIBRARIES INTERFACE_LINK_LIBRARIES PRIVATE_LINK_LIBRARIES)
      set(import_libraries)
      foreach(library ${SWIFTLIB_SINGLE_${library_list}})
        # Ensure that the library is a target.  If an absolute path was given,
        # then we do not have an import library associated with it.  This occurs
        # primarily with ICU (which will be an import library).  Import
        # libraries are only associated with shared libraries, so add an
        # additional check for that as well.
        set(import_library ${library})
        if(TARGET ${library})
          get_target_property(type ${library} TYPE)
          if(${type} STREQUAL "SHARED_LIBRARY")
            set(import_library ${library}_IMPLIB)
          endif()
        endif()
        list(APPEND import_libraries ${import_library})
      endforeach()
      set(SWIFTLIB_SINGLE_${library_list} ${import_libraries})
    endforeach()
  endif()

  if("${libkind}" STREQUAL "OBJECT")
    precondition_list_empty(
        "${SWIFTLIB_SINGLE_PRIVATE_LINK_LIBRARIES}"
        "OBJECT_LIBRARY may not link to anything")
  else()
    target_link_libraries("${target}" PRIVATE
        ${SWIFTLIB_SINGLE_PRIVATE_LINK_LIBRARIES})
  endif()
  if("${libkind}" STREQUAL "OBJECT")
    precondition_list_empty(
        "${SWIFTLIB_SINGLE_INTERFACE_LINK_LIBRARIES}"
        "OBJECT_LIBRARY may not link to anything")
  else()
    target_link_libraries("${target}" INTERFACE
        ${SWIFTLIB_SINGLE_INTERFACE_LINK_LIBRARIES})
  endif()

  set_property(TARGET "${target}" PROPERTY
      LINKER_LANGUAGE "CXX")

  if(target_static)
    set_property(TARGET "${target_static}" APPEND_STRING PROPERTY
        COMPILE_FLAGS " ${c_compile_flags}")
    # FIXME: The fallback paths here are going to be dynamic libraries.
    set(library_search_directories
        "${SWIFTSTATICLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR}"
        "${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFTLIB_SINGLE_SUBDIR}"
        "${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}")
    swift_target_link_search_directories("${target_static}" "${library_search_directories}")
    target_link_libraries("${target_static}" PRIVATE
        ${SWIFTLIB_SINGLE_PRIVATE_LINK_LIBRARIES})
  endif()

  # Do not add code here.
endfunction()

# Add a new Swift host library.
#
# Usage:
#   add_swift_host_library(name
#     [SHARED]
#     [STATIC]
#     [DEPENDS dep1 ...]
#     [INTERFACE_LINK_LIBRARIES dep1 ...]
#     [SWIFT_MODULE_DEPENDS dep1 ...]
#     [LLVM_COMPONENT_DEPENDS comp1 ...]
#     [FILE_DEPENDS target1 ...]
#     [C_COMPILE_FLAGS flag1...]
#     [LINK_FLAGS flag1...]
#     [INSTALL]
#     INSTALL_IN_COMPONENT comp
#     source1 [source2 source3 ...])
#
# name
#   Name of the library (e.g., swiftParse).
#
# SHARED
#   Build a shared library.
#
# STATIC
#   Build a static library.
#
# DEPENDS
#   Targets that this library depends on.
#
# LLVM_COMPONENT_DEPENDS
#   LLVM components this library depends on.
#
# FILE_DEPENDS
#   Additional files this library depends on.
#
# C_COMPILE_FLAGS
#   Extra compiler flags (C, C++, ObjC).
#
# LINK_FLAGS
#   Extra linker flags.
#
# INSTALL_IN_COMPONENT comp
#   The Swift installation component that this library belongs to.
#
# source1 ...
#   Sources to add into this library.
function(add_swift_host_library name)
  set(options
        FORCE_BUILD_OPTIMIZED
        SHARED
        STATIC)
  set(single_parameter_options)
  set(multiple_parameter_options
        C_COMPILE_FLAGS
        DEPENDS
        FILE_DEPENDS
        INTERFACE_LINK_LIBRARIES
        LINK_FLAGS
        LINK_LIBRARIES
        LLVM_COMPONENT_DEPENDS)

  cmake_parse_arguments(ASHL
                        "${options}"
                        "${single_parameter_options}"
                        "${multiple_parameter_options}"
                        ${ARGN})
  set(ASHL_SOURCES ${ASHL_UNPARSED_ARGUMENTS})

  if(ASHL_LINK_LIBRARIES)
    message(SEND_ERROR "library ${name} is using LINK_LIBRARIES parameter which is deprecated.  Please use target_link_libraries instead")
  endif()

  translate_flags(ASHL "${options}")

  if(NOT ASHL_SHARED AND NOT ASHL_STATIC)
    message(FATAL_ERROR "Either SHARED or STATIC must be specified")
  endif()

  _add_swift_library_single(
    ${name}
    ${name}
    ${ASHL_SHARED_keyword}
    ${ASHL_STATIC_keyword}
    ${ASHL_SOURCES}
    ${ASHL_FORCE_BUILD_OPTIMIZED_keyword}
    SDK ${SWIFT_HOST_VARIANT_SDK}
    ARCHITECTURE ${SWIFT_HOST_VARIANT_ARCH}
    DEPENDS ${ASHL_DEPENDS}
    LLVM_COMPONENT_DEPENDS ${ASHL_LLVM_COMPONENT_DEPENDS}
    FILE_DEPENDS ${ASHL_FILE_DEPENDS}
    C_COMPILE_FLAGS ${ASHL_C_COMPILE_FLAGS}
    LINK_FLAGS ${ASHL_LINK_FLAGS}
    INTERFACE_LINK_LIBRARIES ${ASHL_INTERFACE_LINK_LIBRARIES}
    INSTALL_IN_COMPONENT "dev"
    )

  if(NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
    swift_install_in_component(dev
      TARGETS ${name}
      ARCHIVE DESTINATION lib${LLVM_LIBDIR_SUFFIX}
      LIBRARY DESTINATION lib${LLVM_LIBDIR_SUFFIX}
      RUNTIME DESTINATION bin)
  endif()

  swift_is_installing_component(dev is_installing)
  if(NOT is_installing)
    set_property(GLOBAL APPEND PROPERTY SWIFT_BUILDTREE_EXPORTS ${name})
  else()
    set_property(GLOBAL APPEND PROPERTY SWIFT_EXPORTS ${name})
  endif()
endfunction()

# Add a new Swift target library.
#
# NOTE: This has not had the swift host code debrided from it yet. That will be
# in a forthcoming commit.
#
# Usage:
#   add_swift_target_library(name
#     [SHARED]
#     [STATIC]
#     [DEPENDS dep1 ...]
#     [LINK_LIBRARIES dep1 ...]
#     [INTERFACE_LINK_LIBRARIES dep1 ...]
#     [SWIFT_MODULE_DEPENDS dep1 ...]
#     [FRAMEWORK_DEPENDS dep1 ...]
#     [FRAMEWORK_DEPENDS_WEAK dep1 ...]
#     [LLVM_COMPONENT_DEPENDS comp1 ...]
#     [FILE_DEPENDS target1 ...]
#     [TARGET_SDKS sdk1...]
#     [C_COMPILE_FLAGS flag1...]
#     [SWIFT_COMPILE_FLAGS flag1...]
#     [LINK_FLAGS flag1...]
#     [DONT_EMBED_BITCODE]
#     [INSTALL]
#     [IS_STDLIB]
#     [IS_STDLIB_CORE]
#     [TARGET_LIBRARY]
#     INSTALL_IN_COMPONENT comp
#     DEPLOYMENT_VERSION_OSX version
#     DEPLOYMENT_VERSION_IOS version
#     DEPLOYMENT_VERSION_TVOS version
#     DEPLOYMENT_VERSION_WATCHOS version
#     source1 [source2 source3 ...])
#
# name
#   Name of the library (e.g., swiftParse).
#
# SHARED
#   Build a shared library.
#
# STATIC
#   Build a static library.
#
# DEPENDS
#   Targets that this library depends on.
#
# LINK_LIBRARIES
#   Libraries this library depends on.
#
# SWIFT_MODULE_DEPENDS
#   Swift modules this library depends on.
#
# SWIFT_MODULE_DEPENDS_OSX
#   Swift modules this library depends on when built for OS X.
#
# SWIFT_MODULE_DEPENDS_IOS
#   Swift modules this library depends on when built for iOS.
#
# SWIFT_MODULE_DEPENDS_TVOS
#   Swift modules this library depends on when built for tvOS.
#
# SWIFT_MODULE_DEPENDS_WATCHOS
#   Swift modules this library depends on when built for watchOS.
#
# SWIFT_MODULE_DEPENDS_FREEBSD
#   Swift modules this library depends on when built for FreeBSD.
#
# SWIFT_MODULE_DEPENDS_LINUX
#   Swift modules this library depends on when built for Linux.
#
# SWIFT_MODULE_DEPENDS_CYGWIN
#   Swift modules this library depends on when built for Cygwin.
#
# SWIFT_MODULE_DEPENDS_HAIKU
#   Swift modules this library depends on when built for Haiku.
#
# FRAMEWORK_DEPENDS
#   System frameworks this library depends on.
#
# FRAMEWORK_DEPENDS_WEAK
#   System frameworks this library depends on that should be weak-linked
#
# LLVM_COMPONENT_DEPENDS
#   LLVM components this library depends on.
#
# FILE_DEPENDS
#   Additional files this library depends on.
#
# TARGET_SDKS
#   The set of SDKs in which this library is included. If empty, the library
#   is included in all SDKs.
#
# C_COMPILE_FLAGS
#   Extra compiler flags (C, C++, ObjC).
#
# SWIFT_COMPILE_FLAGS
#   Extra compiler flags (Swift).
#
# LINK_FLAGS
#   Extra linker flags.
#
# DONT_EMBED_BITCODE
#   Don't embed LLVM bitcode in this target, even if it is enabled globally.
#
# IS_STDLIB
#   Treat the library as a part of the Swift standard library.
#   IS_STDLIB implies TARGET_LIBRARY.
#
# IS_STDLIB_CORE
#   Compile as the Swift standard library core.
#
# IS_SDK_OVERLAY
#   Treat the library as a part of the Swift SDK overlay.
#   IS_SDK_OVERLAY implies TARGET_LIBRARY and IS_STDLIB.
#
# TARGET_LIBRARY
#   Build library for the target SDKs.
#
# INSTALL_IN_COMPONENT comp
#   The Swift installation component that this library belongs to.
#
# DEPLOYMENT_VERSION_OSX
#   The minimum deployment version to build for if this is an OSX library.
#
# DEPLOYMENT_VERSION_IOS
#   The minimum deployment version to build for if this is an iOS library.
#
# DEPLOYMENT_VERSION_TVOS
#   The minimum deployment version to build for if this is an TVOS library.
#
# DEPLOYMENT_VERSION_WATCHOS
#   The minimum deployment version to build for if this is an WATCHOS library.
#
# source1 ...
#   Sources to add into this library.
function(add_swift_target_library name)
  set(SWIFTLIB_options
        DONT_EMBED_BITCODE
        FORCE_BUILD_OPTIMIZED
        HAS_SWIFT_CONTENT
        IS_SDK_OVERLAY
        IS_STDLIB
        IS_STDLIB_CORE
        NOSWIFTRT
        OBJECT_LIBRARY
        SHARED
        STATIC
        TARGET_LIBRARY)
  set(SWIFTLIB_single_parameter_options
        DEPLOYMENT_VERSION_IOS
        DEPLOYMENT_VERSION_OSX
        DEPLOYMENT_VERSION_TVOS
        DEPLOYMENT_VERSION_WATCHOS
        INSTALL_IN_COMPONENT)
  set(SWIFTLIB_multiple_parameter_options
        C_COMPILE_FLAGS
        DEPENDS
        FILE_DEPENDS
        FRAMEWORK_DEPENDS
        FRAMEWORK_DEPENDS_IOS_TVOS
        FRAMEWORK_DEPENDS_OSX
        FRAMEWORK_DEPENDS_WEAK
        GYB_SOURCES
        INCORPORATE_OBJECT_LIBRARIES
        INCORPORATE_OBJECT_LIBRARIES_SHARED_ONLY
        INTERFACE_LINK_LIBRARIES
        LINK_FLAGS
        LINK_LIBRARIES
        LLVM_COMPONENT_DEPENDS
        PRIVATE_LINK_LIBRARIES
        SWIFT_COMPILE_FLAGS
        SWIFT_COMPILE_FLAGS_IOS
        SWIFT_COMPILE_FLAGS_OSX
        SWIFT_COMPILE_FLAGS_TVOS
        SWIFT_COMPILE_FLAGS_WATCHOS
        SWIFT_MODULE_DEPENDS
        SWIFT_MODULE_DEPENDS_CYGWIN
        SWIFT_MODULE_DEPENDS_FREEBSD
        SWIFT_MODULE_DEPENDS_HAIKU
        SWIFT_MODULE_DEPENDS_IOS
        SWIFT_MODULE_DEPENDS_LINUX
        SWIFT_MODULE_DEPENDS_OSX
        SWIFT_MODULE_DEPENDS_TVOS
        SWIFT_MODULE_DEPENDS_WATCHOS
        SWIFT_MODULE_DEPENDS_WINDOWS
        TARGET_SDKS)

  cmake_parse_arguments(SWIFTLIB
                        "${SWIFTLIB_options}"
                        "${SWIFTLIB_single_parameter_options}"
                        "${SWIFTLIB_multiple_parameter_options}"
                        ${ARGN})
  set(SWIFTLIB_SOURCES ${SWIFTLIB_UNPARSED_ARGUMENTS})

  # Infer arguments.

  if(SWIFTLIB_IS_SDK_OVERLAY)
    set(SWIFTLIB_HAS_SWIFT_CONTENT TRUE)
    set(SWIFTLIB_IS_STDLIB TRUE)
    set(SWIFTLIB_TARGET_LIBRARY TRUE)

    # Install to sdk-overlay by default, but don't hardcode it
    if(NOT SWIFTLIB_INSTALL_IN_COMPONENT)
      set(SWIFTLIB_INSTALL_IN_COMPONENT sdk-overlay)
    endif()
  endif()

  # Standard library is always a target library.
  if(SWIFTLIB_IS_STDLIB)
    set(SWIFTLIB_HAS_SWIFT_CONTENT TRUE)
    set(SWIFTLIB_TARGET_LIBRARY TRUE)
  endif()

  if(NOT SWIFTLIB_TARGET_LIBRARY)
    set(SWIFTLIB_INSTALL_IN_COMPONENT dev)
  endif()

  # If target SDKs are not specified, build for all known SDKs.
  if("${SWIFTLIB_TARGET_SDKS}" STREQUAL "")
    set(SWIFTLIB_TARGET_SDKS ${SWIFT_SDKS})
  endif()
  list_replace(SWIFTLIB_TARGET_SDKS ALL_POSIX_PLATFORMS "ALL_APPLE_PLATFORMS;ANDROID;CYGWIN;FREEBSD;LINUX;HAIKU")
  list_replace(SWIFTLIB_TARGET_SDKS ALL_APPLE_PLATFORMS "${SWIFT_APPLE_PLATFORMS}")

  # All Swift code depends on the standard library, except for the standard
  # library itself.
  if(SWIFTLIB_HAS_SWIFT_CONTENT AND NOT SWIFTLIB_IS_STDLIB_CORE)
    list(APPEND SWIFTLIB_SWIFT_MODULE_DEPENDS Core)

    # swiftSwiftOnoneSupport does not depend on itself, obviously.
    if(NOT ${name} STREQUAL swiftSwiftOnoneSupport)
      # All Swift code depends on the SwiftOnoneSupport in non-optimized mode,
      # except for the standard library itself.
      is_build_type_optimized("${SWIFT_STDLIB_BUILD_TYPE}" optimized)
      if(NOT optimized)
        list(APPEND SWIFTLIB_SWIFT_MODULE_DEPENDS SwiftOnoneSupport)
      endif()
    endif()
  endif()

  if((NOT "${SWIFT_BUILD_STDLIB}") AND
     (NOT "${SWIFTLIB_SWIFT_MODULE_DEPENDS}" STREQUAL ""))
    list(REMOVE_ITEM SWIFTLIB_SWIFT_MODULE_DEPENDS Core SwiftOnoneSupport)
  endif()

  translate_flags(SWIFTLIB "${SWIFTLIB_options}")
  precondition(SWIFTLIB_INSTALL_IN_COMPONENT MESSAGE "INSTALL_IN_COMPONENT is required")

  if(NOT SWIFTLIB_SHARED AND
     NOT SWIFTLIB_STATIC AND
     NOT SWIFTLIB_OBJECT_LIBRARY)
    message(FATAL_ERROR
        "Either SHARED, STATIC, or OBJECT_LIBRARY must be specified")
  endif()

  precondition(SWIFTLIB_TARGET_LIBRARY
    MESSAGE "TARGET_LIBRARY not inferred in add_swift_target_library?!")

  # In the standard library and overlays, warn about implicit overrides
  # as a reminder to consider when inherited protocols need different
  # behavior for their requirements.
  if (SWIFTLIB_IS_STDLIB)
    list(APPEND SWIFTLIB_SWIFT_COMPILE_FLAGS "-warn-implicit-overrides")
  endif()

  if(NOT SWIFT_BUILD_RUNTIME_WITH_HOST_COMPILER AND NOT BUILD_STANDALONE)
    list(APPEND SWIFTLIB_DEPENDS clang)
  endif()

  # If we are building this library for targets, loop through the various
  # SDKs building the variants of this library.
  list_intersect(
      "${SWIFTLIB_TARGET_SDKS}" "${SWIFT_SDKS}" SWIFTLIB_TARGET_SDKS)

  foreach(sdk ${SWIFTLIB_TARGET_SDKS})
    if(NOT SWIFT_SDK_${sdk}_ARCHITECTURES)
      # SWIFT_SDK_${sdk}_ARCHITECTURES is empty, so just continue
      continue()
    endif()

    set(THIN_INPUT_TARGETS)

    # Collect architecture agnostic SDK module dependencies
    set(swiftlib_module_depends_flattened ${SWIFTLIB_SWIFT_MODULE_DEPENDS})
    if(${sdk} STREQUAL OSX)
      list(APPEND swiftlib_module_depends_flattened
           ${SWIFTLIB_SWIFT_MODULE_DEPENDS_OSX})
    elseif(${sdk} STREQUAL IOS OR ${sdk} STREQUAL IOS_SIMULATOR)
      list(APPEND swiftlib_module_depends_flattened
           ${SWIFTLIB_SWIFT_MODULE_DEPENDS_IOS})
    elseif(${sdk} STREQUAL TVOS OR ${sdk} STREQUAL TVOS_SIMULATOR)
      list(APPEND swiftlib_module_depends_flattened
           ${SWIFTLIB_SWIFT_MODULE_DEPENDS_TVOS})
    elseif(${sdk} STREQUAL WATCHOS OR ${sdk} STREQUAL WATCHOS_SIMULATOR)
      list(APPEND swiftlib_module_depends_flattened
           ${SWIFTLIB_SWIFT_MODULE_DEPENDS_WATCHOS})
    elseif(${sdk} STREQUAL FREEBSD)
      list(APPEND swiftlib_module_depends_flattened
           ${SWIFTLIB_SWIFT_MODULE_DEPENDS_FREEBSD})
    elseif(${sdk} STREQUAL LINUX OR ${sdk} STREQUAL ANDROID)
      list(APPEND swiftlib_module_depends_flattened
           ${SWIFTLIB_SWIFT_MODULE_DEPENDS_LINUX})
    elseif(${sdk} STREQUAL CYGWIN)
      list(APPEND swiftlib_module_depends_flattened
           ${SWIFTLIB_SWIFT_MODULE_DEPENDS_CYGWIN})
    elseif(${sdk} STREQUAL HAIKU)
      list(APPEND swiftlib_module_depends_flattened
           ${SWIFTLIB_SWIFT_MODULE_DEPENDS_HAIKU})
    elseif(${sdk} STREQUAL WINDOWS)
      list(APPEND swiftlib_module_depends_flattened
           ${SWIFTLIB_SWIFT_MODULE_DEPENDS_WINDOWS})
    endif()

    # Collect architecture agnostic SDK framework dependencies
    set(swiftlib_framework_depends_flattened ${SWIFTLIB_FRAMEWORK_DEPENDS})
    if(${sdk} STREQUAL OSX)
      list(APPEND swiftlib_framework_depends_flattened
           ${SWIFTLIB_FRAMEWORK_DEPENDS_OSX})
    elseif(${sdk} STREQUAL IOS OR ${sdk} STREQUAL IOS_SIMULATOR OR
           ${sdk} STREQUAL TVOS OR ${sdk} STREQUAL TVOS_SIMULATOR)
      list(APPEND swiftlib_framework_depends_flattened
           ${SWIFTLIB_FRAMEWORK_DEPENDS_IOS_TVOS})
    endif()

    # Collect architecutre agnostic compiler flags
    set(swiftlib_swift_compile_flags_all ${SWIFTLIB_SWIFT_COMPILE_FLAGS})
    if(${sdk} STREQUAL OSX)
      list(APPEND swiftlib_swift_compile_flags_all
           ${SWIFTLIB_SWIFT_COMPILE_FLAGS_OSX})
    elseif(${sdk} STREQUAL IOS OR ${sdk} STREQUAL IOS_SIMULATOR)
      list(APPEND swiftlib_swift_compile_flags_all
           ${SWIFTLIB_SWIFT_COMPILE_FLAGS_IOS})
    elseif(${sdk} STREQUAL TVOS OR ${sdk} STREQUAL TVOS_SIMULATOR)
      list(APPEND swiftlib_swift_compile_flags_all
           ${SWIFTLIB_SWIFT_COMPILE_FLAGS_TVOS})
    elseif(${sdk} STREQUAL WATCHOS OR ${sdk} STREQUAL WATCHOS_SIMULATOR)
      list(APPEND swiftlib_swift_compile_flags_all
           ${SWIFTLIB_SWIFT_COMPILE_FLAGS_WATCHOS})
    elseif(${sdk} STREQUAL WINDOWS)
      # FIXME(SR2005) static and shared are not mutually exclusive; however
      # since we do a single build of the sources, this doesn't work for
      # building both simultaneously.  Effectively, only shared builds are
      # supported on windows currently.
      if(SWIFTLIB_SHARED)
        list(APPEND swiftlib_swift_compile_flags_all -D_WINDLL)
        if(SWIFTLIB_IS_STDLIB_CORE)
          list(APPEND swiftlib_swift_compile_flags_all -DswiftCore_EXPORTS)
        endif()
      elseif(SWIFTLIB_STATIC)
        list(APPEND swiftlib_swift_compile_flags_all -D_LIB)
      endif()
    endif()


    # Collect architecture agnostic SDK linker flags
    set(swiftlib_link_flags_all ${SWIFTLIB_LINK_FLAGS})
    if(${sdk} STREQUAL IOS_SIMULATOR AND ${name} STREQUAL swiftMediaPlayer)
      # message("DISABLING AUTOLINK FOR swiftMediaPlayer")
      list(APPEND swiftlib_link_flags_all "-Xlinker" "-ignore_auto_link")
    endif()

    # We unconditionally removed "-z,defs" from CMAKE_SHARED_LINKER_FLAGS in
    # swift_common_standalone_build_config_llvm within
    # SwiftSharedCMakeConfig.cmake, where it was added by a call to
    # HandleLLVMOptions.
    #
    # Rather than applying it to all targets and libraries, we here add it
    # back to supported targets and libraries only.  This is needed for ELF
    # targets only; however, RemoteMirror needs to build with undefined
    # symbols.
    if(${SWIFT_SDK_${sdk}_OBJECT_FORMAT} STREQUAL ELF AND
       NOT ${name} STREQUAL swiftRemoteMirror)
      list(APPEND swiftlib_link_flags_all "-Wl,-z,defs")
    endif()

    # For each architecture supported by this SDK
    foreach(arch ${SWIFT_SDK_${sdk}_ARCHITECTURES})
      # Configure variables for this subdirectory.
      set(VARIANT_SUFFIX "-${SWIFT_SDK_${sdk}_LIB_SUBDIR}-${arch}")
      set(VARIANT_NAME "${name}${VARIANT_SUFFIX}")
      set(MODULE_VARIANT_SUFFIX "-swiftmodule${VARIANT_SUFFIX}")
      set(MODULE_VARIANT_NAME "${name}${MODULE_VARIANT_SUFFIX}")

      # Map dependencies over to the appropriate variants.
      set(swiftlib_link_libraries)
      foreach(lib ${SWIFTLIB_LINK_LIBRARIES})
        if(TARGET "${lib}${VARIANT_SUFFIX}")
          list(APPEND swiftlib_link_libraries "${lib}${VARIANT_SUFFIX}")
        else()
          list(APPEND swiftlib_link_libraries "${lib}")
        endif()
      endforeach()

      # Swift compiles depend on swift modules, while links depend on
      # linked libraries.  Find targets for both of these here.
      set(swiftlib_module_dependency_targets)
      set(swiftlib_private_link_libraries_targets)

      if(NOT BUILD_STANDALONE)
        foreach(mod ${swiftlib_module_depends_flattened})
          list(APPEND swiftlib_module_dependency_targets
              "swift${mod}${MODULE_VARIANT_SUFFIX}")

          list(APPEND swiftlib_private_link_libraries_targets
              "swift${mod}${VARIANT_SUFFIX}")
        endforeach()
      endif()

      foreach(lib ${SWIFTLIB_PRIVATE_LINK_LIBRARIES})
        if(TARGET "${lib}${VARIANT_SUFFIX}")
          list(APPEND swiftlib_private_link_libraries_targets
              "${lib}${VARIANT_SUFFIX}")
        else()
          list(APPEND swiftlib_private_link_libraries_targets "${lib}")
        endif()
      endforeach()

      # Add PrivateFrameworks, rdar://28466433
      set(swiftlib_c_compile_flags_all ${SWIFTLIB_C_COMPILE_FLAGS})
      if(sdk IN_LIST SWIFT_APPLE_PLATFORMS AND SWIFTLIB_IS_SDK_OVERLAY)
        set(swiftlib_swift_compile_private_frameworks_flag "-Fsystem" "${SWIFT_SDK_${sdk}_ARCH_${arch}_PATH}/System/Library/PrivateFrameworks/")
      endif()

      list(APPEND swiftlib_c_compile_flags_all "-DSWIFT_TARGET_LIBRARY_NAME=${name}")

      # Add this library variant.
      _add_swift_library_single(
        ${VARIANT_NAME}
        ${name}
        ${SWIFTLIB_SHARED_keyword}
        ${SWIFTLIB_STATIC_keyword}
        ${SWIFTLIB_OBJECT_LIBRARY_keyword}
        ${SWIFTLIB_SOURCES}
        MODULE_TARGET ${MODULE_VARIANT_NAME}
        SDK ${sdk}
        ARCHITECTURE ${arch}
        DEPENDS ${SWIFTLIB_DEPENDS}
        LINK_LIBRARIES ${swiftlib_link_libraries}
        FRAMEWORK_DEPENDS ${swiftlib_framework_depends_flattened}
        FRAMEWORK_DEPENDS_WEAK ${SWIFTLIB_FRAMEWORK_DEPENDS_WEAK}
        LLVM_COMPONENT_DEPENDS ${SWIFTLIB_LLVM_COMPONENT_DEPENDS}
        FILE_DEPENDS ${SWIFTLIB_FILE_DEPENDS} ${swiftlib_module_dependency_targets}
        C_COMPILE_FLAGS ${swiftlib_c_compile_flags_all}
        SWIFT_COMPILE_FLAGS ${swiftlib_swift_compile_flags_all} ${swiftlib_swift_compile_flags_arch} ${swiftlib_swift_compile_private_frameworks_flag}
        LINK_FLAGS ${swiftlib_link_flags_all}
        PRIVATE_LINK_LIBRARIES ${swiftlib_private_link_libraries_targets}
        INCORPORATE_OBJECT_LIBRARIES ${SWIFTLIB_INCORPORATE_OBJECT_LIBRARIES}
        INCORPORATE_OBJECT_LIBRARIES_SHARED_ONLY ${SWIFTLIB_INCORPORATE_OBJECT_LIBRARIES_SHARED_ONLY}
        ${SWIFTLIB_DONT_EMBED_BITCODE_keyword}
        ${SWIFTLIB_IS_STDLIB_keyword}
        ${SWIFTLIB_IS_STDLIB_CORE_keyword}
        ${SWIFTLIB_IS_SDK_OVERLAY_keyword}
        ${SWIFTLIB_TARGET_LIBRARY_keyword}
        ${SWIFTLIB_FORCE_BUILD_OPTIMIZED_keyword}
        ${SWIFTLIB_NOSWIFTRT_keyword}
        INSTALL_IN_COMPONENT "${SWIFTLIB_INSTALL_IN_COMPONENT}"
        DEPLOYMENT_VERSION_OSX "${SWIFTLIB_DEPLOYMENT_VERSION_OSX}"
        DEPLOYMENT_VERSION_IOS "${SWIFTLIB_DEPLOYMENT_VERSION_IOS}"
        DEPLOYMENT_VERSION_TVOS "${SWIFTLIB_DEPLOYMENT_VERSION_TVOS}"
        DEPLOYMENT_VERSION_WATCHOS "${SWIFTLIB_DEPLOYMENT_VERSION_WATCHOS}"
        GYB_SOURCES ${SWIFTLIB_GYB_SOURCES}
      )

      if(NOT SWIFTLIB_OBJECT_LIBRARY)
        # Add dependencies on the (not-yet-created) custom lipo target.
        foreach(DEP ${SWIFTLIB_LINK_LIBRARIES})
          if (NOT "${DEP}" STREQUAL "icucore")
            add_dependencies(${VARIANT_NAME}
              "${DEP}-${SWIFT_SDK_${sdk}_LIB_SUBDIR}")
          endif()
        endforeach()

        if (SWIFTLIB_IS_STDLIB AND SWIFTLIB_STATIC)
          # Add dependencies on the (not-yet-created) custom lipo target.
          foreach(DEP ${SWIFTLIB_LINK_LIBRARIES})
            if (NOT "${DEP}" STREQUAL "icucore")
              add_dependencies("${VARIANT_NAME}-static"
                "${DEP}-${SWIFT_SDK_${sdk}_LIB_SUBDIR}-static")
            endif()
          endforeach()
        endif()

        # Note this thin library.
        list(APPEND THIN_INPUT_TARGETS ${VARIANT_NAME})
      endif()
    endforeach()

    if(NOT SWIFTLIB_OBJECT_LIBRARY)
      # Determine the name of the universal library.
      if(SWIFTLIB_SHARED)
        if("${sdk}" STREQUAL "WINDOWS")
          set(UNIVERSAL_LIBRARY_NAME
            "${SWIFTLIB_DIR}/${SWIFT_SDK_${sdk}_LIB_SUBDIR}/${name}.dll")
        else()
          set(UNIVERSAL_LIBRARY_NAME
            "${SWIFTLIB_DIR}/${SWIFT_SDK_${sdk}_LIB_SUBDIR}/${CMAKE_SHARED_LIBRARY_PREFIX}${name}${CMAKE_SHARED_LIBRARY_SUFFIX}")
        endif()
      else()
        if("${sdk}" STREQUAL "WINDOWS")
          set(UNIVERSAL_LIBRARY_NAME
            "${SWIFTLIB_DIR}/${SWIFT_SDK_${sdk}_LIB_SUBDIR}/${name}.lib")
        else()
          set(UNIVERSAL_LIBRARY_NAME
            "${SWIFTLIB_DIR}/${SWIFT_SDK_${sdk}_LIB_SUBDIR}/${CMAKE_STATIC_LIBRARY_PREFIX}${name}${CMAKE_STATIC_LIBRARY_SUFFIX}")
        endif()
      endif()

      set(lipo_target "${name}-${SWIFT_SDK_${sdk}_LIB_SUBDIR}")
      if("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin" AND SWIFTLIB_SHARED)
        set(codesign_arg CODESIGN)
      endif()
      precondition(THIN_INPUT_TARGETS)
      _add_swift_lipo_target(SDK
                               ${sdk}
                             TARGET
                               ${lipo_target}
                             OUTPUT
                               ${UNIVERSAL_LIBRARY_NAME}
                             ${codesign_arg}
                             ${THIN_INPUT_TARGETS})

      # Cache universal libraries for dependency purposes
      set(UNIVERSAL_LIBRARY_NAMES_${SWIFT_SDK_${sdk}_LIB_SUBDIR}
        ${UNIVERSAL_LIBRARY_NAMES_${SWIFT_SDK_${sdk}_LIB_SUBDIR}}
        ${lipo_target}
        CACHE INTERNAL "UNIVERSAL_LIBRARY_NAMES_${SWIFT_SDK_${sdk}_LIB_SUBDIR}")

      # Determine the subdirectory where this library will be installed.
      set(resource_dir_sdk_subdir "${SWIFT_SDK_${sdk}_LIB_SUBDIR}")
      precondition(resource_dir_sdk_subdir)

      if(SWIFTLIB_SHARED)
        set(resource_dir "swift")
        set(file_permissions
            OWNER_READ OWNER_WRITE OWNER_EXECUTE
            GROUP_READ GROUP_EXECUTE
            WORLD_READ WORLD_EXECUTE)
      else()
        set(resource_dir "swift_static")
        set(file_permissions
            OWNER_READ OWNER_WRITE
            GROUP_READ
            WORLD_READ)
      endif()

      set(optional_arg)
      if(sdk IN_LIST SWIFT_APPLE_PLATFORMS)
        # Allow installation of stdlib without building all variants on Darwin.
        set(optional_arg "OPTIONAL")
      endif()

      if(sdk STREQUAL WINDOWS AND CMAKE_SYSTEM_NAME STREQUAL Windows)
        swift_install_in_component("${SWIFTLIB_INSTALL_IN_COMPONENT}"
          TARGETS ${name}-windows-${SWIFT_PRIMARY_VARIANT_ARCH}
          RUNTIME DESTINATION "bin"
          LIBRARY DESTINATION "lib${LLVM_LIBDIR_SUFFIX}/${resource_dir}/${resource_dir_sdk_subdir}/${SWIFT_PRIMARY_VARIANT_ARCH}"
          ARCHIVE DESTINATION "lib${LLVM_LIBDIR_SUFFIX}/${resource_dir}/${resource_dir_sdk_subdir}/${SWIFT_PRIMARY_VARIANT_ARCH}"
          PERMISSIONS ${file_permissions})
      else()
        swift_install_in_component("${SWIFTLIB_INSTALL_IN_COMPONENT}"
            FILES "${UNIVERSAL_LIBRARY_NAME}"
            DESTINATION "lib${LLVM_LIBDIR_SUFFIX}/${resource_dir}/${resource_dir_sdk_subdir}"
            PERMISSIONS ${file_permissions}
            "${optional_arg}")
      endif()
      if(sdk STREQUAL WINDOWS)
        foreach(arch ${SWIFT_SDK_WINDOWS_ARCHITECTURES})
          if(TARGET ${name}-windows-${arch}_IMPLIB)
            get_target_property(import_library ${name}-windows-${arch}_IMPLIB IMPORTED_LOCATION)
            swift_install_in_component(${SWIFTLIB_INSTALL_IN_COMPONENT}
              FILES ${import_library}
              DESTINATION "lib${LLVM_LIBDIR_SUFFIX}/${resource_dir}/${resource_dir_sdk_subdir}/${arch}"
              PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ)
          endif()
        endforeach()
      endif()

      swift_is_installing_component("${SWIFTLIB_INSTALL_IN_COMPONENT}" is_installing)
      if(NOT is_installing)
        set_property(GLOBAL APPEND PROPERTY SWIFT_BUILDTREE_EXPORTS ${VARIANT_NAME})
      else()
        set_property(GLOBAL APPEND PROPERTY SWIFT_EXPORTS ${VARIANT_NAME})
      endif()

      # If we built static variants of the library, create a lipo target for
      # them.
      set(lipo_target_static)
      if (SWIFTLIB_IS_STDLIB AND SWIFTLIB_STATIC)
        set(THIN_INPUT_TARGETS_STATIC)
        foreach(TARGET ${THIN_INPUT_TARGETS})
          list(APPEND THIN_INPUT_TARGETS_STATIC "${TARGET}-static")
        endforeach()

        set(lipo_target_static
            "${name}-${SWIFT_SDK_${sdk}_LIB_SUBDIR}-static")
        set(UNIVERSAL_LIBRARY_NAME
            "${SWIFTSTATICLIB_DIR}/${SWIFT_SDK_${sdk}_LIB_SUBDIR}/${CMAKE_STATIC_LIBRARY_PREFIX}${name}${CMAKE_STATIC_LIBRARY_SUFFIX}")
        _add_swift_lipo_target(SDK
                                 ${sdk}
                               TARGET
                                 ${lipo_target_static}
                               OUTPUT
                                 "${UNIVERSAL_LIBRARY_NAME}"
                               ${THIN_INPUT_TARGETS_STATIC})
        swift_install_in_component("${SWIFTLIB_INSTALL_IN_COMPONENT}"
            FILES "${UNIVERSAL_LIBRARY_NAME}"
            DESTINATION "lib${LLVM_LIBDIR_SUFFIX}/swift_static/${resource_dir_sdk_subdir}"
            PERMISSIONS
              OWNER_READ OWNER_WRITE
              GROUP_READ
              WORLD_READ
            "${optional_arg}")
      endif()

      # Add Swift standard library targets as dependencies to the top-level
      # convenience target.
      set(FILTERED_UNITTESTS
            swiftStdlibCollectionUnittest
            swiftStdlibUnicodeUnittest)

      foreach(arch ${SWIFT_SDK_${sdk}_ARCHITECTURES})
        set(VARIANT_SUFFIX "-${SWIFT_SDK_${sdk}_LIB_SUBDIR}-${arch}")
        if(TARGET "swift-stdlib${VARIANT_SUFFIX}" AND
           TARGET "swift-test-stdlib${VARIANT_SUFFIX}")
          add_dependencies("swift-stdlib${VARIANT_SUFFIX}"
              ${lipo_target}
              ${lipo_target_static})
          if(NOT "${name}" IN_LIST FILTERED_UNITTESTS)
            add_dependencies("swift-test-stdlib${VARIANT_SUFFIX}"
                ${lipo_target}
                ${lipo_target_static})
          endif()
        endif()
      endforeach()
    endif()
  endforeach()
endfunction()

# Add an executable compiled for a given variant.
#
# Don't use directly, use add_swift_executable and add_swift_target_executable
# instead.
#
# See add_swift_executable for detailed documentation.
#
# Additional parameters:
#   [SDK sdk]
#     SDK to build for.
#
#   [ARCHITECTURE architecture]
#     Architecture to build for.
function(_add_swift_executable_single name)
  # Parse the arguments we were given.
  cmake_parse_arguments(SWIFTEXE_SINGLE
    "EXCLUDE_FROM_ALL"
    "SDK;ARCHITECTURE"
    "DEPENDS;LLVM_COMPONENT_DEPENDS;LINK_LIBRARIES;COMPILE_FLAGS"
    ${ARGN})

  set(SWIFTEXE_SINGLE_SOURCES ${SWIFTEXE_SINGLE_UNPARSED_ARGUMENTS})

  translate_flag(${SWIFTEXE_SINGLE_EXCLUDE_FROM_ALL}
      "EXCLUDE_FROM_ALL"
      SWIFTEXE_SINGLE_EXCLUDE_FROM_ALL_FLAG)

  # Check arguments.
  precondition(SWIFTEXE_SINGLE_SDK MESSAGE "Should specify an SDK")
  precondition(SWIFTEXE_SINGLE_ARCHITECTURE MESSAGE "Should specify an architecture")

  # Determine compiler flags.
  set(c_compile_flags)
  set(link_flags)

  # Prepare linker search directories.
  set(library_search_directories
        "${SWIFTLIB_DIR}/${SWIFT_SDK_${SWIFTEXE_SINGLE_SDK}_LIB_SUBDIR}")

  # Add variant-specific flags.
  _add_variant_c_compile_flags(
    SDK "${SWIFTEXE_SINGLE_SDK}"
    ARCH "${SWIFTEXE_SINGLE_ARCHITECTURE}"
    BUILD_TYPE "${CMAKE_BUILD_TYPE}"
    ENABLE_ASSERTIONS "${LLVM_ENABLE_ASSERTIONS}"
    ENABLE_LTO "${SWIFT_TOOLS_ENABLE_LTO}"
    ANALYZE_CODE_COVERAGE "${SWIFT_ANALYZE_CODE_COVERAGE}"
    RESULT_VAR_NAME c_compile_flags)
  _add_variant_link_flags(
    SDK "${SWIFTEXE_SINGLE_SDK}"
    ARCH "${SWIFTEXE_SINGLE_ARCHITECTURE}"
    BUILD_TYPE "${CMAKE_BUILD_TYPE}"
    ENABLE_ASSERTIONS "${LLVM_ENABLE_ASSERTIONS}"
    ENABLE_LTO "${SWIFT_TOOLS_ENABLE_LTO}"
    LTO_OBJECT_NAME "${name}-${SWIFTEXE_SINGLE_SDK}-${SWIFTEXE_SINGLE_ARCHITECTURE}"
    ANALYZE_CODE_COVERAGE "${SWIFT_ANALYZE_CODE_COVERAGE}"
    RESULT_VAR_NAME link_flags
    LINK_LIBRARIES_VAR_NAME link_libraries
    LIBRARY_SEARCH_DIRECTORIES_VAR_NAME library_search_directories)

  if(${SWIFTEXE_SINGLE_SDK} IN_LIST SWIFT_APPLE_PLATFORMS)
    list(APPEND link_flags
        "-Xlinker" "-rpath"
        "-Xlinker" "@executable_path/../lib/swift/${SWIFT_SDK_${SWIFTEXE_SINGLE_SDK}_LIB_SUBDIR}")
  endif()

  _list_add_string_suffix(
      "${SWIFTEXE_SINGLE_LINK_LIBRARIES}"
      "-${SWIFT_SDK_${SWIFTEXE_SINGLE_SDK}_LIB_SUBDIR}-${SWIFTEXE_SINGLE_ARCHITECTURE}"
      SWIFTEXE_SINGLE_LINK_LIBRARIES_TARGETS)
  set(SWIFTEXE_SINGLE_LINK_LIBRARIES ${SWIFTEXE_SINGLE_LINK_LIBRARIES_TARGETS})

  handle_swift_sources(
      dependency_target
      unused_module_dependency_target
      unused_sib_dependency_target
      unused_sibopt_dependency_target
      unused_sibgen_dependency_target
      SWIFTEXE_SINGLE_SOURCES SWIFTEXE_SINGLE_EXTERNAL_SOURCES ${name}
      DEPENDS
        ${SWIFTEXE_SINGLE_DEPENDS}
      MODULE_NAME ${name}
      SDK ${SWIFTEXE_SINGLE_SDK}
      ARCHITECTURE ${SWIFTEXE_SINGLE_ARCHITECTURE}
      COMPILE_FLAGS ${SWIFTEXE_SINGLE_COMPILE_FLAGS}
      IS_MAIN)
  add_swift_source_group("${SWIFTEXE_SINGLE_EXTERNAL_SOURCES}")

  add_executable(${name}
      ${SWIFTEXE_SINGLE_EXCLUDE_FROM_ALL_FLAG}
      ${SWIFTEXE_SINGLE_SOURCES}
      ${SWIFTEXE_SINGLE_EXTERNAL_SOURCES})

  add_dependencies_multiple_targets(
      TARGETS "${name}"
      DEPENDS
        ${dependency_target}
        ${LLVM_COMMON_DEPENDS}
        ${SWIFTEXE_SINGLE_DEPENDS})
  llvm_update_compile_flags("${name}")

  # Convert variables to space-separated strings.
  _list_escape_for_shell("${c_compile_flags}" c_compile_flags)
  _list_escape_for_shell("${link_flags}" link_flags)

  set_property(TARGET ${name} APPEND_STRING PROPERTY
      COMPILE_FLAGS " ${c_compile_flags}")
  swift_target_link_search_directories("${name}" "${library_search_directories}")
  set_property(TARGET ${name} APPEND_STRING PROPERTY
      LINK_FLAGS " ${link_flags}")
  set_property(TARGET ${name} APPEND PROPERTY LINK_LIBRARIES ${link_libraries})
  if (SWIFT_PARALLEL_LINK_JOBS)
    set_property(TARGET ${name} PROPERTY JOB_POOL_LINK swift_link_job_pool)
  endif()
  set_output_directory(${name}
      BINARY_DIR ${SWIFT_RUNTIME_OUTPUT_INTDIR}
      LIBRARY_DIR ${SWIFT_LIBRARY_OUTPUT_INTDIR})

  target_link_libraries("${name}" PRIVATE ${SWIFTEXE_SINGLE_LINK_LIBRARIES})
  swift_common_llvm_config("${name}" ${SWIFTEXE_SINGLE_LLVM_COMPONENT_DEPENDS})

  set_target_properties(${name} PROPERTIES FOLDER "Swift executables")
endfunction()

macro(add_swift_tool_subdirectory name)
  add_llvm_subdirectory(SWIFT TOOL ${name})
endmacro()

macro(add_swift_lib_subdirectory name)
  add_llvm_subdirectory(SWIFT LIB ${name})
endmacro()

function(add_swift_host_tool executable)
  set(options)
  set(single_parameter_options SWIFT_COMPONENT)
  set(multiple_parameter_options LINK_LIBRARIES)

  cmake_parse_arguments(ASHT
    "${options}"
    "${single_parameter_options}"
    "${multiple_parameter_options}"
    ${ARGN})

  if(ASHT_LINK_LIBRARIES)
    message(SEND_ERROR "${executable} is using LINK_LIBRARIES parameter which is deprecated.  Please use target_link_libraries instead")
  endif()

  precondition(ASHT_SWIFT_COMPONENT
               MESSAGE "Swift Component is required to add a host tool")

  # Create the executable rule.
  _add_swift_executable_single(${executable}
    SDK ${SWIFT_HOST_VARIANT_SDK}
    ARCHITECTURE ${SWIFT_HOST_VARIANT_ARCH}
    ${ASHT_UNPARSED_ARGUMENTS})

  swift_install_in_component(${ASHT_SWIFT_COMPONENT}
    TARGETS ${executable}
    RUNTIME DESTINATION bin)

  swift_is_installing_component(${ASHT_SWIFT_COMPONENT} is_installing)

  if(NOT is_installing)
    set_property(GLOBAL APPEND PROPERTY SWIFT_BUILDTREE_EXPORTS ${executable})
  else()
    set_property(GLOBAL APPEND PROPERTY SWIFT_EXPORTS ${executable})
  endif()
endfunction()

# This declares a swift host tool that links with libfuzzer.
function(add_swift_fuzzer_host_tool executable)
  # First create our target. We do not actually parse the argument since we do
  # not care about the arguments, we just pass them all through to
  # add_swift_host_tool.
  add_swift_host_tool(${executable} ${ARGN})

  # Then make sure that we pass the -fsanitize=fuzzer flag both on the cflags
  # and cxx flags line.
  target_compile_options(${executable} PRIVATE "-fsanitize=fuzzer")
  target_link_libraries(${executable} PRIVATE "-fsanitize=fuzzer")
endfunction()

macro(add_swift_tool_symlink name dest component)
  add_llvm_tool_symlink(${name} ${dest} ALWAYS_GENERATE)
  llvm_install_symlink(${name} ${dest} ALWAYS_GENERATE COMPONENT ${component})
endmacro()