[Threading] Fix threading package defaults.

These are better done via the SwiftConfigureSDK mechanism rather than
how I was doing them previously.  Additionally, I've changed the way
that the swift-threading-package option works.  In addition to
specifying just a single package name, you can specify it as a CMake
list (i.e.  separate by semicolons) of colon-separated `sdk:package`
pairs, e.g.  `osx:darwin;linux:pthreads`.  You can also override it
for all SDKs and then specify for a given SDK; specifications for a
particular SDK take precedence over the global override.  For instance
`pthreads;osx:darwin` says to use `pthreads` except on the OS X SDK
where we should use `darwin`.

Author: al45tair

CMakeLists.txt

@@ -192,16 +192,6 @@ option(SWIFT_STDLIB_ENABLE_UNICODE_DATA
     NOTE: Disabling this will cause many String methods to crash."
     TRUE)
 
-include(Threading)
-
-threading_package_default("${SWIFT_HOST_VARIANT_SDK}"
-  SWIFT_THREADING_PACKAGE_default)
-
-set(SWIFT_THREADING_PACKAGE "${SWIFT_THREADING_PACKAGE_default}"
-    CACHE STRING
-    "The threading package to use.  Must be one of 'none', 'pthreads',
-    'darwin', 'linux', 'win32', 'c11'.")
-
 option(SWIFT_BUILD_DYNAMIC_SDK_OVERLAY
     "Build dynamic variants of the Swift SDK overlay"
     TRUE)
@@ -589,6 +579,12 @@ cmake_dependent_option(SWIFT_ENABLE_SOURCEKIT_TESTS
   "Enable running SourceKit tests" TRUE
   "SWIFT_BUILD_SOURCEKIT" FALSE)
 
+option(SWIFT_THREADING_PACKAGE
+  "Override the threading package used for the build.  This can either be a
+   single package name, or a semicolon separated sequence of sdk:package pairs.
+   Valid package names are 'pthreads', 'darwin', 'linux', 'win32', 'c11', 'none'
+   or the empty string for the SDK default.")
+
 #
 # End of user-configurable options.
 #
@@ -820,6 +816,30 @@ if("${CMAKE_C_COMPILER_ID}" STREQUAL "MSVC" OR "${CMAKE_CXX_SIMULATE_ID}" STREQU
   set(SWIFT_COMPILER_IS_MSVC_LIKE TRUE)
 endif()
 
+#
+# Display a message if the threading package has been overridden
+#
+
+if(SWIFT_THREADING_PACKAGE)
+  message(STATUS "")
+  message(STATUS "Threading package override enabled")
+  foreach(elt ${SWIFT_THREADING_PACKAGE})
+    string(REPLACE ":" ";" elt_list "${elt}")
+    list(LENGTH elt_list elt_list_len)
+    if(elt_list_len EQUAL 1)
+      set(elt_sdk "Global")
+      list(GET elt_list 0 elt_package)
+    else()
+      list(GET elt_list 0 elt_sdk)
+      list(GET elt_list 1 elt_package)
+      string(TOUPPER "${elt_sdk}" elt_sdk)
+    endif()
+    string(TOLOWER "${elt_package}" elt_package)
+    message(STATUS "  ${elt_sdk}: ${elt_package}")
+  endforeach()
+  message(STATUS "")
+endif()
+
 #
 # Configure SDKs.
 #
@@ -1054,7 +1074,6 @@ if(SWIFT_BUILD_STDLIB OR SWIFT_BUILD_SDK_OVERLAY)
   message(STATUS "  Leak Detection Checker Entrypoints: ${SWIFT_RUNTIME_ENABLE_LEAK_CHECKER}")
   message(STATUS "")
 
-  message(STATUS "Threading Package:                  ${SWIFT_THREADING_PACKAGE}")
   message(STATUS "Differentiable Programming Support: ${SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING}")
   message(STATUS "Concurrency Support:                ${SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY}")
   message(STATUS "Distributed Support:                ${SWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED}")

cmake/modules/AddSwift.cmake

@@ -4,7 +4,6 @@ include(SwiftXcodeSupport)
 include(SwiftWindowsSupport)
 include(SwiftAndroidSupport)
 include(SwiftCXXUtils)
-include(Threading)
 
 function(_swift_gyb_target_sources target scope)
   file(GLOB GYB_UNICODE_DATA ${SWIFT_SOURCE_DIR}/utils/UnicodeData/*)
@@ -309,7 +308,7 @@ function(_add_host_variant_c_compile_flags target)
       $<$<COMPILE_LANGUAGE:C,CXX,OBJC,OBJCXX>:SWIFT_ENABLE_RUNTIME_FUNCTION_COUNTERS>)
   endif()
 
-  threading_package_name("${SWIFT_HOST_VARIANT_SDK}" _threading_package)
+  string(TOUPPER "${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_THREADING_PACKAGE}" _threading_package)
   target_compile_definitions(${target} PRIVATE
     "SWIFT_THREADING_${_threading_package}")
 

cmake/modules/AddSwiftUnittests.cmake

@@ -1,6 +1,5 @@
 
 include(AddSwift)
-include(Threading)
 
 add_custom_target(SwiftUnitTests)
 
@@ -54,7 +53,8 @@ function(add_swift_unittest test_dirname)
     target_compile_definitions("${test_dirname}" PRIVATE
       SWIFT_STDLIB_SINGLE_THREADED_CONCURRENCY)
   endif()
-  threading_package_name("${SWIFT_HOST_VARIANT_SDK}" _threading_package)
+
+  string(TOUPPER "${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_THREADING_PACKAGE}" _threading_package)
   target_compile_definitions("${test_dirname}" PRIVATE
     "SWIFT_THREADING_${_threading_package}")
 

cmake/modules/SwiftConfigureSDK.cmake

@@ -13,6 +13,7 @@ function(_report_sdk prefix)
   message(STATUS "${SWIFT_SDK_${prefix}_NAME} SDK:")
   message(STATUS "  Object File Format: ${SWIFT_SDK_${prefix}_OBJECT_FORMAT}")
   message(STATUS "  Swift Standard Library Path: ${SWIFT_SDK_${prefix}_LIB_SUBDIR}")
+  message(STATUS "  Threading Package: ${SWIFT_SDK_${prefix}_THREADING_PACKAGE}")
 
   if("${prefix}" STREQUAL "WINDOWS")
     message(STATUS "  UCRT Version: ${UCRTVersion}")
@@ -101,6 +102,34 @@ function(remove_sdk_unsupported_archs name os sdk_path architectures_var)
   set("${architectures_var}" ${architectures} PARENT_SCOPE)
 endfunction()
 
+# Work out which threading package to use by consulting SWIFT_THREADING_PACKAGE
+function(find_threading_package sdk default package_var)
+  set(global_override)
+  foreach(elt ${SWIFT_THREADING_PACKAGE})
+    string(REPLACE ":" ";" elt_list "${elt}")
+    list(LENGTH elt_list elt_list_len)
+    if(elt_list_len EQUAL 1)
+      list(GET elt_list 0 global_override)
+      string(TOLOWER "${global_override}" global_override)
+    else()
+      list(GET elt_list 0 elt_sdk)
+      list(GET elt_list 1 elt_package)
+      string(TOUPPER "${elt_sdk}" elt_sdk)
+      string(TOLOWER "${elt_package}" elt_package)
+
+      if("${elt_sdk}" STREQUAL "${sdk}")
+        set("${package_var}" "${elt_package}" PARENT_SCOPE)
+        return()
+      endif()
+    endif()
+  endforeach()
+  if(global_override)
+    set("${package_var}" "${global_override}" PARENT_SCOPE)
+  else()
+    set("${package_var}" "${default}" PARENT_SCOPE)
+  endif()
+endfunction()
+
 # Configure an SDK
 #
 # Usage:
@@ -179,6 +208,7 @@ macro(configure_sdk_darwin
   set(SWIFT_SDK_${prefix}_STATIC_LIBRARY_SUFFIX ".a")
   set(SWIFT_SDK_${prefix}_IMPORT_LIBRARY_PREFIX "")
   set(SWIFT_SDK_${prefix}_IMPORT_LIBRARY_SUFFIX "")
+  find_threading_package(${prefix} "darwin" SWIFT_SDK_${prefix}_THREADING_PACKAGE)
 
   set(SWIFT_SDK_${prefix}_ARCHITECTURES ${architectures})
   if(SWIFT_DARWIN_SUPPORTED_ARCHS)
@@ -297,6 +327,15 @@ macro(configure_sdk_unix name architectures)
       -Xcc --gcc-toolchain=/usr
     CACHE STRING "Extra flags for compiling the C++ overlay")
 
+  set(_default_threading_package "pthreads")
+  if("${prefix}" STREQUAL "LINUX")
+    set(_default_threading_package "linux")
+  elseif("${prefix}" STREQUAL "WASI")
+    set(_default_threading_package "none")
+  endif()
+  find_threading_package(${prefix} ${_default_threading_package}
+    SWIFT_SDK_${prefix}_THREADING_PACKAGE)
+
   foreach(arch ${architectures})
     if("${prefix}" STREQUAL "ANDROID")
       swift_android_sysroot(android_sysroot)
@@ -423,6 +462,7 @@ macro(configure_sdk_windows name environment architectures)
   set(SWIFT_SDK_${prefix}_STATIC_LIBRARY_SUFFIX ".lib")
   set(SWIFT_SDK_${prefix}_IMPORT_LIBRARY_PREFIX "")
   set(SWIFT_SDK_${prefix}_IMPORT_LIBRARY_SUFFIX ".lib")
+  find_threading_package(${prefix} "win32" SWIFT_SDK_${prefix}_THREADING_PACKAGE)
 
   foreach(arch ${architectures})
     if(arch STREQUAL armv7)
@@ -489,5 +529,6 @@ function(configure_target_variant prefix name sdk build_config lib_subdir)
   set(SWIFT_VARIANT_${prefix}_STATIC_LIBRARY_SUFFIX ${SWIFT_SDK_${sdk}_STATIC_LIBRARY_SUFFIX})
   set(SWIFT_VARIANT_${prefix}_IMPORT_LIBRARY_PREFIX ${SWIFT_SDK_${sdk}_IMPORT_LIBRARY_PREFIX})
   set(SWIFT_VARIANT_${prefix}_IMPORT_LIBRARY_SUFFIX ${SWIFT_SDK_${sdk}_IMPORT_LIBRARY_SUFFIX})
+  find_threading_package(${prefix} ${SWIFT_SDK_${sdk}_THREADING_PACKAGE} SWIFT_VARIANT_${prefix}_THREADING_PACKAGE)
 endfunction()
 

cmake/modules/Threading.cmake

@@ -1,7 +1,6 @@
 
 include(AddSwift)
 include(SwiftSource)
-include(Threading)
 
 function(add_dependencies_multiple_targets)
   cmake_parse_arguments(
@@ -355,7 +354,7 @@ function(_add_target_variant_c_compile_flags)
     list(APPEND result "-DSWIFT_STDLIB_SINGLE_THREADED_CONCURRENCY")
   endif()
 
-  threading_package_name("${CFLAGS_SDK}" _threading_package)
+  string(TOUPPER "${SWIFT_SDK_${CFLAGS_SDK}_THREADING_PACKAGE}" _threading_package)
   list(APPEND result "-DSWIFT_THREADING_${_threading_package}")
 
   if(SWIFT_STDLIB_OS_VERSIONING)

stdlib/cmake/modules/AddSwiftStdlib.cmake

@@ -1,7 +1,6 @@
 include_guard(GLOBAL)
 
 include(${CMAKE_CURRENT_LIST_DIR}/../../../cmake/modules/SwiftUtils.cmake)
-include(${CMAKE_CURRENT_LIST_DIR}/../../../cmake/modules/Threading.cmake)
 
 precondition(SWIFT_HOST_VARIANT_SDK)
 precondition(SWIFT_DARWIN_PLATFORMS)
@@ -191,16 +190,6 @@ else()
   set(SWIFT_CONCURRENCY_GLOBAL_EXECUTOR_default "dispatch")
 endif()
 
-include(Threading)
-
-threading_package_default("${SWIFT_HOST_VARIANT_SDK}"
-  SWIFT_THREADING_PACKAGE_default)
-
-set(SWIFT_THREADING_PACKAGE "${SWIFT_THREADING_PACKAGE_default}"
-    CACHE STRING
-    "The threading package to use.  Must be one of 'none', 'pthreads',
-    'darwin', 'linux', 'win32', 'c11'.")
-
 set(SWIFT_CONCURRENCY_GLOBAL_EXECUTOR
     "${SWIFT_CONCURRENCY_GLOBAL_EXECUTOR_default}" CACHE STRING
     "Build the concurrency library to use the given global executor (options: dispatch, singlethreaded, hooked)")

stdlib/cmake/modules/StdlibOptions.cmake

@@ -1,6 +1,5 @@
 include(macCatalystUtils)
 include(SwiftUtils)
-include(Threading)
 
 function(_compute_lto_swift_flag option out_var)
   string(TOLOWER "${option}" lowercase_option)
@@ -327,7 +326,7 @@ function(_add_target_variant_swift_compile_flags
     list(APPEND result "-D" "SWIFT_STDLIB_SINGLE_THREADED_CONCURRENCY")
   endif()
 
-  threading_package_name("${sdk}" _threading_package)
+  string(TOUPPER "${SWIFT_SDK_${sdk}_THREADING_PACKAGE}" _threading_package)
   list(APPEND result "-D" "SWIFT_THREADING_${_threading_package}")
 
   set("${result_var_name}" "${result}" PARENT_SCOPE)
@@ -483,7 +482,7 @@ function(_compile_swift_files
     list(APPEND swift_flags "-Xfrontend" "-library-level"  "-Xfrontend" "api")
   endif()
 
-  if(SWIFT_THREADING_PACKAGE STREQUAL "none")
+  if("${SWIFT_SDK_${SWIFTFILE_SDK}_THREADING_PACKAGE}" STREQUAL "none")
     list(APPEND swift_flags "-Xfrontend" "-assume-single-threaded")
   endif()
 

stdlib/cmake/modules/SwiftSource.cmake

@@ -1,7 +1,6 @@
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules")
 
 include(SwiftTestUtils)
-include(Threading)
 
 function(swift_configure_lit_site_cfg source_path destination_path installed_name)
   if (CMAKE_CFG_INTDIR STREQUAL ".")
@@ -395,14 +394,7 @@ foreach(SDK ${SWIFT_SDKS})
           list(APPEND LIT_ARGS "--param" "string_processing")
         endif()
 
-        if("${SWIFT_SDK_${SDK}_THREADING_PACKAGE}")
-          list(APPEND LIT_ARGS "--param" "threading=${SWIFT_SDK_${SDK}_THREADING_PACKAGE}")
-        else()
-          threading_package_default("${SDK}" SWIFT_THREADING_PACKAGE)
-          list(APPEND LIT_ARGS "--param"
-            "threading=${SWIFT_THREADING_PACKAGE}")
-        endif()
-
+        list(APPEND LIT_ARGS "--param" "threading=${SWIFT_SDK_${SDK}_THREADING_PACKAGE}")
         foreach(test_subset ${TEST_SUBSETS})
           set(directories)
           set(dependencies ${test_dependencies})

test/CMakeLists.txt

@@ -99,11 +99,6 @@ if "@SWIFT_OPTIMIZED@" == "TRUE":
 if "@SWIFT_STDLIB_SINGLE_THREADED_CONCURRENCY@" == "TRUE":
     config.available_features.add("single_threaded_concurrency")
 
-if "@SWIFT_THREADING_PACKAGE@" != "none":
-    # This is not called "threading" because we might want that later
-    config.available_features.add("thread_safe_runtime")
-    config.available_features.add("threading_@SWIFT_THREADING_PACKAGE@")
-
 if "@SWIFT_ENABLE_REFLECTION@" == "TRUE":
     config.available_features.add("reflection")
 

test/lit.site.cfg.in

@@ -206,7 +206,7 @@ KNOWN_SETTINGS=(
     swift-stdlib-has-dladdr                       "1"               "whether to build stdlib assuming the runtime environment provides dladdr API"
     swift-stdlib-supports-backtrace-reporting     ""                "whether to build stdlib assuming the runtime environment provides the backtrace(3) API, if not set defaults to true on all platforms except for Cygwin, Haiku and wasm"
     swift-runtime-static-image-inspection         "0"               "whether to build stdlib assuming the runtime environment only supports a single runtime image with Swift code"
-    swift-threading-package                       ""                "which threading package to use for Swift; valid values are empty string (default based on platform), 'pthreads', 'darwin', 'linux', 'win32', 'c11', 'none'"
+    swift-threading-package                       ""                "override the threading package for the host build; this is either a single package or a semicolon-separated list of sdk:package pairs.  Valid packages are empty string (no override), 'pthreads', 'darwin', 'linux', 'win32', 'c11', 'none'"
     swift-stdlib-single-threaded-concurrency      "0"               "build Swift concurrency in single-threaded mode"
     swift-stdlib-concurrency-tracing              ""                "whether to enable tracing signposts for concurrency; default is 1 on Darwin platforms, 0 otherwise"
     swift-stdlib-os-versioning                    "1"               "whether to build stdlib with availability based on OS versions (Darwin only)"
@@ -2227,15 +2227,34 @@ for host in "${ALL_HOSTS[@]}"; do
                     )
                 fi
 
-                if [[ "${SWIFT_THREADING_PACKAGE}" ]] ; then
-                    case "${SWIFT_THREADING_PACKAGE}" in
+                # SWIFT_THREADING_PACKAGE can be:
+                #
+                #    - Empty
+                #    - A single package name
+                #    - A semicolon separated sequence of sdk:package pairs
+                #
+                OFS=$IFS
+                IFS=';'
+                for elt in $SWIFT_THREADING_PACKAGE; do
+                    if [[ $elt == *:* ]]; then
+                        sdk=${elt/:*/}
+                        package=${elt/*:/}
+                    else
+                        sdk='<any>'
+                        package=$elt
+                    fi
+
+                    case $package in
                         "" | pthreads | darwin | linux | win32 | c11 | none) ;;
                         *)
-                            echo "build-script: unknown threading package ${SWIFT_THREADING_PACKAGE}; must be one of 'pthreads', 'darwin', 'linux', 'win32', 'c11', 'none', or empty for platform default" >&2
-                            exit 1
-                            ;;
+                        echo "build-script: unknown threading package $package for sdk $sdk; must be one of 'pthreads', 'darwin', 'linux', 'win32', 'c11', 'none', or empty for sdk default"
+                        exit 1
+                        ;;
                     esac
+                done
+                IFS=$OFS
 
+                if [[ "$SWIFT_THREADING_PACKAGE" ]] ; then
                     cmake_options=(
                         "${cmake_options[@]}"
                         -DSWIFT_THREADING_PACKAGE:STRING="${SWIFT_THREADING_PACKAGE}"