[CMake] Introduce availability macros for all known stdlib releases

Introduce "SwiftStdlib x.y"-style availability macros for all known releases of the stdlib, adding them to the swift flags of all Swift libraries and tests.

Author: lorentey

CMakeLists.txt

@@ -525,6 +525,18 @@ if(SWIFT_ENABLE_DISPATCH AND NOT CMAKE_SYSTEM_NAME STREQUAL Darwin)
   endif()
 endif()
 
+set(SWIFT_STDLIB_AVAILABILITY_DEFINITIONS
+  "SwiftStdlib 5.0:macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2"
+  "SwiftStdlib 5.1:macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0"
+  "SwiftStdlib 5.2:macOS 10.15.4, iOS 13.4, watchOS 6.2, tvOS 13.4"
+  "SwiftStdlib 5.3:macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0"
+  "SwiftStdlib 5.4:macOS 11.3, iOS 14.5, watchOS 7.4, tvOS 14.5"
+  "SwiftStdlib 5.5:macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0"
+  "SwiftStdlib 5.6:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999"
+  "SwiftStdlib 9999:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999" # Unknown future release
+  CACHE STRING
+  "Availability macros for stdlib versions")
+
 #
 # Include CMake modules
 #

stdlib/cmake/modules/AddSwiftStdlib.cmake

@@ -1722,6 +1722,11 @@ function(add_swift_target_library name)
         "Either SHARED, STATIC, or OBJECT_LIBRARY must be specified")
   endif()
 
+  # Define availability macros.
+  foreach(def ${SWIFT_STDLIB_AVAILABILITY_DEFINITIONS})
+    list(APPEND SWIFTLIB_SWIFT_COMPILE_FLAGS "-Xfrontend" "-define-availability" "-Xfrontend" "${def}") 
+  endforeach()
+  
   # In the standard library and overlays, warn about implicit overrides
   # as a reminder to consider when inherited protocols need different
   # behavior for their requirements.

stdlib/private/StdlibUnittest/CMakeLists.txt

@@ -55,8 +55,6 @@ add_swift_target_library(swiftStdlibUnittest ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES}
   SWIFT_MODULE_DEPENDS_HAIKU Glibc
   SWIFT_MODULE_DEPENDS_WINDOWS CRT WinSDK
   SWIFT_COMPILE_FLAGS ${swift_stdlib_unittest_compile_flags} ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
-    -Xfrontend -define-availability
-    -Xfrontend "SwiftStdlib 5.1:macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0"
   INSTALL_IN_COMPONENT stdlib-experimental
   DARWIN_INSTALL_NAME_DIR "${SWIFT_DARWIN_STDLIB_PRIVATE_INSTALL_NAME_DIR}"
   LINK_LIBRARIES ${swift_stdlib_unittest_link_libraries})

stdlib/public/Concurrency/CMakeLists.txt

@@ -127,8 +127,6 @@ add_swift_target_library(swift_Concurrency ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} I
     ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
     -parse-stdlib
     -Xfrontend -enable-experimental-concurrency
-    -Xfrontend -define-availability
-    -Xfrontend "SwiftStdlib 5.1:macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0"
     ${SWIFT_RUNTIME_CONCURRENCY_SWIFT_FLAGS}
   ${swift_concurrency_options}
   INSTALL_IN_COMPONENT ${swift_concurrency_install_component}

stdlib/public/Distributed/CMakeLists.txt

@@ -34,10 +34,6 @@ add_swift_target_library(swift_Distributed ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} I
     ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
     -parse-stdlib
     -Xfrontend -enable-experimental-distributed
-    -Xfrontend -define-availability
-    -Xfrontend "SwiftStdlib 5.1:macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0"
-    -Xfrontend -define-availability
-    -Xfrontend "SwiftStdlib 5.6:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999"
   LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
 
   SWIFT_MODULE_DEPENDS _Concurrency

test/CMakeLists.txt

@@ -385,6 +385,10 @@ foreach(SDK ${SWIFT_SDKS})
           list(APPEND LIT_ARGS "--param" "distributed")
         endif()
 
+        # Define availability macros, escaping semicolons to get around CMake
+        string(REPLACE ";" "\\$<SEMICOLON>" availability_defs "${SWIFT_STDLIB_AVAILABILITY_DEFINITIONS}")
+        list(APPEND LIT_ARGS "--param" "availability_macros=${availability_defs}")
+
         foreach(test_subset ${TEST_SUBSETS})
           set(directories)
           set(dependencies ${test_dependencies})

test/lit.cfg

@@ -431,10 +431,10 @@ swift_version = lit_config.params.get('swift-version',
 lit_config.note('Compiling with -swift-version ' + swift_version)
 config.swift_test_options = '-swift-version ' + swift_version
 
-# Define a macro for the next release OS version.
-swift_stdlib_macro = '\'SwiftStdlib 5.1:macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0\''
-config.swift_frontend_test_options += ' -define-availability ' + swift_stdlib_macro
-config.swift_driver_test_options += ' -Xfrontend -define-availability -Xfrontend ' + swift_stdlib_macro
+# Define availability macros for known stdlib releases.
+for macro in lit_config.params.get('availability_macros').split(";"):
+    config.swift_frontend_test_options += " -define-availability '{0}'".format(macro)
+    config.swift_driver_test_options += " -Xfrontend -define-availability -Xfrontend '{0}'".format(macro)
 
 differentiable_programming = lit_config.params.get('differentiable_programming', None)
 if differentiable_programming is not None: