[Apple Silicon] [Build] Filter out any architectures that are unsupported by the SDKs

Author: shahmishal

cmake/modules/SwiftConfigureSDK.cmake

@@ -85,6 +85,38 @@ function(_report_sdk prefix)
   message(STATUS "")
 endfunction()
 
+# Remove architectures not supported by the SDK from the given list.
+function(remove_sdk_unsupported_archs name os sdk_path architectures_var)
+  execute_process(COMMAND
+      /usr/libexec/PlistBuddy -c "Print :SupportedTargets:${os}:Archs" ${sdk_path}/SDKSettings.plist
+    OUTPUT_VARIABLE sdk_supported_archs
+    RESULT_VARIABLE plist_error)
+
+  if (NOT plist_error EQUAL 0)
+    message(STATUS "${os} SDK at ${sdk_path} does not publish its supported architectures")
+    return()
+  endif()
+
+  set(architectures)
+  foreach(arch ${${architectures_var}})
+    if(sdk_supported_archs MATCHES "${arch}\n")
+      list(APPEND architectures ${arch})
+    elseif(arch MATCHES "^armv7(s)?$" AND os STREQUAL "iphoneos")
+      # 32-bit iOS 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 "iphonesimulator")
+      # 32-bit iOS simulatoris not listed explicitly in SDK settings.
+      message(STATUS "Assuming ${name} SDK at ${sdk_path} supports architecture ${arch}")
+      list(APPEND architectures ${arch})
+    else()
+      message(STATUS "${name} SDK at ${sdk_path} does not support architecture ${arch}")
+    endif()
+  endforeach()
+
+  set("${architectures_var}" ${architectures} PARENT_SCOPE)
+endfunction()
+
 # Configure an SDK
 #
 # Usage:
@@ -164,6 +196,9 @@ macro(configure_sdk_darwin
       SWIFT_SDK_${prefix}_ARCHITECTURES)  # result
   endif()
 
+  # Remove any architectures not supported by the SDK.
+  remove_sdk_unsupported_archs(${name} ${xcrun_name} ${SWIFT_SDK_${prefix}_PATH} SWIFT_SDK_${prefix}_ARCHITECTURES)
+
   list_intersect(
     "${SWIFT_DARWIN_MODULE_ARCHS}"            # lhs
     "${architectures}"                        # rhs

utils/build-script

@@ -350,6 +350,19 @@ def apply_default_arguments(toolchain, args):
                 target.arch in supported_archs)
         ]
 
+    # Filter out any macOS stdlib deployment targets that are not supported
+    # by the macOS SDK.
+    if platform.system() == "Darwin":
+        targets = StdlibDeploymentTarget.get_targets_by_name(
+            args.stdlib_deployment_targets)
+        args.stdlib_deployment_targets = [
+            target.name
+            for target in targets
+            if (target.platform.is_darwin and
+                target.platform.sdk_supports_architecture(
+                    target.arch, args.darwin_xcrun_toolchain))
+        ]
+
     # Include the Darwin module-only architectures in the CMake options.
     if args.swift_darwin_module_archs:
         args.extra_cmake_options.append(

utils/swift_build_support/swift_build_support/host_specific_configuration.py

@@ -41,7 +41,8 @@ def __init__(self, host_target, args):
             stdlib_targets_to_configure = [host_target]
             stdlib_targets_to_build = set(stdlib_targets_to_configure)
 
-        if args.stdlib_deployment_targets == []:
+        if (hasattr(args, 'stdlib_deployment_targets') and
+                args.stdlib_deployment_targets == []):
             stdlib_targets_to_configure = []
             stdlib_targets_to_build = []
 

utils/swift_build_support/swift_build_support/targets.py

@@ -11,6 +11,13 @@
 import os
 import platform
 
+from . import shell
+
+try:
+    from build_swift.build_swift.wrappers import xcrun
+except ImportError:
+    from build_swift.wrappers import xcrun
+
 
 class Platform(object):
     """
@@ -86,6 +93,39 @@ def uses_host_tests(self):
         """
         return self.is_embedded and not self.is_simulator
 
+    def sdk_supports_architecture(self, arch, toolchain):
+        """
+        Convenience function for checking whether the SDK supports the
+        target architecture.
+        """
+
+        # The names match up with the xcrun SDK names.
+        xcrun_sdk_name = self.name
+
+        # 32-bit iOS and iOS simulator are supported, but are not covered
+        # by the SDK settings. Handle this special case here.
+        if (xcrun_sdk_name == 'iphoneos' and
+           (arch == 'armv7' or arch == 'armv7s')):
+            return True
+
+        if (xcrun_sdk_name == 'iphonesimulator' and arch == 'i386'):
+            return True
+
+        sdk_path = xcrun.sdk_path(sdk=xcrun_sdk_name, toolchain=toolchain)
+        if not sdk_path:
+            raise RuntimeError('Cannot find SDK path for %s' % xcrun_sdk_name)
+
+        # Find the SDKSettings.plist for this sdK
+        plistCommand = [
+            '/usr/libexec/PlistBuddy',
+            '-c',
+            'Print :SupportedTargets:%s:Archs' % (self.name),
+            '%s/SDKSettings.plist' % (sdk_path)
+        ]
+
+        sdk_archs = shell.capture(plistCommand, dry_run=False, echo=True)
+        return arch in sdk_archs
+
 
 class AndroidPlatform(Platform):
     @property