Extract experimental feature flags

Extracting experimental feature flags into a separate file so that we
can add Allan as a code owner of just that file. He has to deal with
breakage when folks remove these flags improperly.

Author: etcwilde

.github/CODEOWNERS

@@ -32,9 +32,10 @@
 # TODO: /README.md
 
 # Runtimes
-/Runtimes/**/*.cmake                       @etcwilde @compnerd @edymtt @justice-adams-apple
-/Runtimes/**/CMakeLists.txt                @etcwilde @compnerd @edymtt @justice-adams-apple
-/Runtimes/Core/cmake/caches/Vendors/Apple/ @etcwilde @shahmishal @edymtt @justice-adams-apple
+/Runtimes/**/*.cmake                                    @etcwilde @compnerd @edymtt @justice-adams-apple
+/Runtimes/**/CMakeLists.txt                             @etcwilde @compnerd @edymtt @justice-adams-apple
+/Runtimes/Core/cmake/caches/Vendors/Apple/              @etcwilde @shahmishal @edymtt @justice-adams-apple
+/Runtimes/Core/cmake/modules/ExperimentalFeatures.cmake @tshortli @etcwilde @compnerd @edymtt @justice-adams-apple
 
 # SwiftCompilerSources
 /SwiftCompilerSources                     @eeckstein

Runtimes/Core/CMakeLists.txt

@@ -178,20 +178,7 @@ add_compile_options(
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-runtime-compatibility-version none>"
   "$<$<COMPILE_LANGUAGE:Swift>:-disable-autolinking-runtime-compatibility-dynamic-replacements>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-autolinking-runtime-compatibility-concurrency>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NoncopyableGenerics2>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SuppressedAssociatedTypes>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SE427NoInferenceOnExtension>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-strict-memory-safety>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NonescapableTypes>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependence>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature MemberImportVisibility>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature TypedThrows>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature Macros>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature FreestandingMacros>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature BitwiseCopyable>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature Extern>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature ValueGenerics>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature AddressableParameters>"
   # TODO: we should reevaluate if it still makes sense to restrict this
   # to Darwin, https://github.com/swiftlang/swift/issues/79279
   "$<$<AND:$<PLATFORM_ID:Darwin>,$<COMPILE_LANGUAGE:Swift>>:-save-optimization-record=bitstream>"
@@ -209,6 +196,8 @@ add_compile_options(
   "$<$<AND:$<BOOL:${SwiftCore_ENABLE_LIBRARY_EVOLUTION}>,$<COMPILE_LANGUAGE:Swift>>:-enable-library-evolution>"
   "$<$<AND:$<BOOL:${SwiftCore_ENABLE_PRESPECIALIZATION}>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -prespecialize-generic-metadata>")
 
+include(ExperimentalFeatures)
+
 include_directories(include)
 
 add_subdirectory(LLVMSupport)

Runtimes/Core/cmake/modules/ExperimentalFeatures.cmake

@@ -0,0 +1,14 @@
+add_compile_options(
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NoncopyableGenerics2>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SuppressedAssociatedTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SE427NoInferenceOnExtension>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NonescapableTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature MemberImportVisibility>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature TypedThrows>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature Macros>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature FreestandingMacros>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature BitwiseCopyable>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature Extern>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature ValueGenerics>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature AddressableParameters>")