[watchos] Switch to building i386 sim and armv7k interfaces only

When the deployment target is above 9.0 (7.0 for simulator), only build
the module content such as the swiftinterface, as the support for
building dylibs for those arches goes away in that release.

Author: benlangmuir

CMakeLists.txt

@@ -468,7 +468,7 @@ set(SWIFT_DARWIN_SUPPORTED_ARCHS "" CACHE STRING
   "Semicolon-separated list of architectures to configure on Darwin platforms. \
 If left empty all default architectures are configured.")
 
-set(SWIFT_DARWIN_MODULE_ARCHS "" CACHE STRING
+set(SWIFT_DARWIN_MODULE_ARCHS "i386;armv7k" CACHE STRING
   "Semicolon-separated list of architectures to configure Swift module-only \
 targets on Darwin platforms. These targets are in addition to the full \
 library targets.")

cmake/modules/DarwinSDKs.cmake

@@ -8,13 +8,6 @@ set(SUPPORTED_OSX_ARCHS "x86_64;arm64")
 set(SUPPORTED_XROS_ARCHS "arm64;arm64e")
 set(SUPPORTED_XROS_SIMULATOR_ARCHS "arm64")
 
-if(SWIFT_DARWIN_DEPLOYMENT_VERSION_WATCHOS VERSION_GREATER_EQUAL 7.0)
-  list(REMOVE_ITEM SUPPORTED_WATCHOS_SIMULATOR_ARCHS "i386")
-endif()
-if(SWIFT_DARWIN_DEPLOYMENT_VERSION_WATCHOS VERSION_GREATER_EQUAL 9.0)
-  list(REMOVE_ITEM SUPPORTED_WATCHOS_ARCHS "armv7k")
-endif()
-
 is_sdk_requested(OSX swift_build_osx)
 if(swift_build_osx)
   configure_sdk_darwin(

cmake/modules/SwiftConfigureSDK.cmake

@@ -68,7 +68,7 @@ function(_report_sdk prefix)
 endfunction()
 
 # Remove architectures not supported by the SDK from the given list.
-function(remove_sdk_unsupported_archs name os sdk_path architectures_var)
+function(remove_sdk_unsupported_archs name os sdk_path deployment_version architectures_var)
   execute_process(COMMAND
       /usr/libexec/PlistBuddy -c "Print :SupportedTargets:${os}:Archs" ${sdk_path}/SDKSettings.plist
     OUTPUT_VARIABLE sdk_supported_archs
@@ -87,11 +87,11 @@ function(remove_sdk_unsupported_archs name os sdk_path architectures_var)
       # 32-bit iOS simulator is not listed explicitly in SDK settings.
       message(STATUS "Assuming ${name} SDK at ${sdk_path} supports architecture ${arch}")
       list(APPEND architectures ${arch})
-    elseif(arch STREQUAL "armv7k" AND os STREQUAL "watchos")
+    elseif(arch STREQUAL "armv7k" AND os STREQUAL "watchos" AND deployment_version VERSION_LESS "9.0")
       # 32-bit watchOS is not listed explicitly in SDK settings.
       message(STATUS "Assuming ${name} SDK at ${sdk_path} supports architecture ${arch}")
       list(APPEND architectures ${arch})
-    elseif(arch STREQUAL "i386" AND os STREQUAL "watchsimulator")
+    elseif(arch STREQUAL "i386" AND os STREQUAL "watchsimulator" AND deployment_version VERSION_LESS "7.0")
       # 32-bit watchOS simulator is not listed explicitly in SDK settings.
       message(STATUS "Assuming ${name} SDK at ${sdk_path} supports architecture ${arch}")
       list(APPEND architectures ${arch})
@@ -229,7 +229,7 @@ macro(configure_sdk_darwin
   endif()
 
   # Remove any architectures not supported by the SDK.
-  remove_sdk_unsupported_archs(${name} ${xcrun_name} ${SWIFT_SDK_${prefix}_PATH} SWIFT_SDK_${prefix}_ARCHITECTURES)
+  remove_sdk_unsupported_archs(${name} ${xcrun_name} ${SWIFT_SDK_${prefix}_PATH} "${SWIFT_SDK_${prefix}_DEPLOYMENT_VERSION}" SWIFT_SDK_${prefix}_ARCHITECTURES)
 
   list_intersect(
     "${SWIFT_DARWIN_MODULE_ARCHS}"            # lhs