Extend freestanding to support targeting Darwin platforms (#40202)

* add an option to add freestanding to the Darwin platform, so that
  to get expected compile behaviours (e.g. setting the install name)
* rework testing configuration to relax assumptions about freestanding
* add a preset to test such configuration (at least for PR testing)

Addresses rdar://85465396

Author: edymtt

CMakeLists.txt

@@ -669,6 +669,9 @@ set(SWIFT_DARWIN_PLATFORMS "IOS" "IOS_SIMULATOR" "TVOS" "TVOS_SIMULATOR" "WATCHO
 set(SWIFT_APPLE_PLATFORMS ${SWIFT_DARWIN_PLATFORMS})
 if(SWIFT_FREESTANDING_FLAVOR STREQUAL "apple")
   list(APPEND SWIFT_APPLE_PLATFORMS "FREESTANDING")
+  if(SWIFT_FREESTANDING_IS_DARWIN)
+    list(APPEND SWIFT_DARWIN_PLATFORMS "FREESTANDING")
+  endif()
 endif()
 
 # Configuration flags passed to all of our invocations of gyb.  Try to

stdlib/public/Platform/CMakeLists.txt

@@ -17,7 +17,7 @@ if(SWIFT_ENABLE_REFLECTION)
 endif()
 
 set(swiftDarwin_target_sdks ALL_APPLE_PLATFORMS)
-if(SWIFT_FREESTANDING_FLAVOR STREQUAL "apple")
+if(SWIFT_FREESTANDING_FLAVOR STREQUAL "apple" AND NOT SWIFT_FREESTANDING_IS_DARWIN)
   set(swiftDarwin_target_sdks ALL_APPLE_PLATFORMS FREESTANDING)
 endif()
 

test/CMakeLists.txt

@@ -203,6 +203,8 @@ normalize_boolean_spelling(SWIFT_ENABLE_RUNTIME_FUNCTION_COUNTERS)
 normalize_boolean_spelling(SWIFT_HAVE_LIBXML2)
 normalize_boolean_spelling(SWIFT_INCLUDE_TOOLS)
 normalize_boolean_spelling(SWIFT_STDLIB_STATIC_PRINT)
+normalize_boolean_spelling(SWIFT_ENABLE_DISPATCH)
+normalize_boolean_spelling(SWIFT_STDLIB_ENABLE_OBJC_INTEROP)
 is_build_type_optimized("${SWIFT_STDLIB_BUILD_TYPE}" SWIFT_OPTIMIZED)
 
 set(profdata_merge_worker

test/lit.cfg

@@ -938,18 +938,24 @@ if run_vendor == 'apple':
     # The "freestanding" tests will link against the static libswiftCore.a and
     # cannot use any of Obj-C / Dispatch / Foundation.
     if "-freestanding" in config.variant_suffix:
-        config.target_runtime = "native"
-        config.available_features.remove('libdispatch')
-        config.available_features.remove('foundation')
-        config.available_features.remove('objc_interop')
+        if not config.swift_freestanding_is_darwin:
+            config.target_runtime = "native"
+        if not config.swift_enable_dispatch:
+            config.available_features.remove('libdispatch')
+        if not config.swift_freestanding_is_darwin:
+            config.available_features.remove('foundation')
+        if not config.swift_stdlib_enable_objc_interop:
+            config.available_features.remove('objc_interop')
         config.available_features.add('freestanding')
 
         # Build all "freestanding" tests with -disable-objc-interop
-        swift_execution_tests_extra_flags += ' -Xfrontend -disable-objc-interop'
+        if not config.swift_stdlib_enable_objc_interop:
+            swift_execution_tests_extra_flags += ' -Xfrontend -disable-objc-interop'
 
         # The Concurrency module is not available in "freestanding" mode.
-        swift_execution_tests_extra_flags += \
-                ' -Xfrontend -disable-implicit-concurrency-module-import'
+        if not 'concurrency' in config.available_features:
+            swift_execution_tests_extra_flags += \
+                    ' -Xfrontend -disable-implicit-concurrency-module-import'
 
         # To have visible references from symbolic manglings
         swift_execution_tests_extra_flags += \
@@ -958,9 +964,11 @@ if run_vendor == 'apple':
         # Link all "freestanding" tests with -dead_strip, which can effectively
         # even remove parts of the stdlib and runtime, if it's not needed. Since
         # it's a very desired behavior, let's enable it for all executable tests.
-        swift_execution_tests_extra_flags += ' -Xlinker -dead_strip'
+        if not config.swift_freestanding_is_darwin:
+            swift_execution_tests_extra_flags += ' -Xlinker -dead_strip'
 
-        swift_execution_tests_extra_flags += ' -experimental-hermetic-seal-at-link -lto=llvm-full'
+        if not config.swift_freestanding_is_darwin:
+            swift_execution_tests_extra_flags += ' -experimental-hermetic-seal-at-link -lto=llvm-full'
 
         # Build a resource dir for freestanding tests.
         new_resource_dir = os.path.join(config.test_exec_root, "resource_dir")
@@ -972,6 +980,8 @@ if run_vendor == 'apple':
         symlink_if_not_exists("clang", "clang")
         symlink_if_not_exists("shims", "shims")
         symlink_if_not_exists("freestanding", "macosx")
+        if config.swift_freestanding_is_darwin:
+            symlink_if_not_exists("apinotes", "apinotes")
         config.resource_dir_opt = "-resource-dir %s" % new_resource_dir
         lit_config.note('Using freestanding resource dir: ' + new_resource_dir)
 
@@ -1160,7 +1170,13 @@ if run_vendor == 'apple':
         'Running tests on %s version %s (%s)' %
         (sw_vers_name, sw_vers_vers, sw_vers_build))
 
-    config.target_sdk_name = xcrun_sdk_name
+    if "-freestanding" in config.variant_suffix and config.swift_freestanding_is_darwin:
+        # This will ensure we are able to find libraries
+        # and resource dir at the correct path in tests that require
+        # Foundation and ObjectiveC capabilities
+        config.target_sdk_name = config.freestanding_sdk_name
+    else:
+        config.target_sdk_name = xcrun_sdk_name
     config.target_ld = "%s ld -L%r" % (xcrun_prefix, make_path(test_resource_dir, config.target_sdk_name))
 
     maccatalyst_extra_frameworks = ""

test/lit.site.cfg.in

@@ -142,6 +142,12 @@ if "@SWIFT_STDLIB_STATIC_PRINT@" == "TRUE":
 if "@SWIFT_ENABLE_EXPERIMENTAL_STRING_PROCESSING@" == "TRUE":
     config.available_features.add('string_processing')
 
+config.swift_freestanding_is_darwin = "@SWIFT_FREESTANDING_IS_DARWIN@" == "TRUE"
+config.swift_enable_dispatch = "@SWIFT_ENABLE_DISPATCH@" == "TRUE"
+config.swift_stdlib_enable_objc_interop = "@SWIFT_STDLIB_ENABLE_OBJC_INTEROP@" == "TRUE"
+# Configured in DarwinSDKs.cmake
+config.freestanding_sdk_name = "@SWIFT_SDK_FREESTANDING_LIB_SUBDIR@"
+
 # Let the main config do the real work.
 if config.test_exec_root is None:
     config.test_exec_root = os.path.dirname(os.path.realpath(__file__))

test/stdlib/symbols-depended-on-in-freestanding.darwin.test-sh

@@ -5,5 +5,6 @@
 
 // REQUIRES: freestanding
 // REQUIRES: executable_test
+// UNSUPPORTED: objc_interop
 
 // RUN: %{python} %utils/check_freestanding_dependencies.py --vendor %target-vendor --library %test-resource-dir/freestanding/libswiftCore.a --nm-path %llvm-nm

utils/build-presets.ini

@@ -2564,6 +2564,30 @@ mixin-preset=stdlib_S_standalone_minimal_macho_x86_64,build
 test
 validation-test
 
+[preset: stdlib_S_standalone_darwin_x86_64,build]
+mixin-preset=
+    stdlib_S_standalone,build
+
+build-subdir=stdlib_S_standalone_darwin
+enable-experimental-differentiable-programming=0
+enable-experimental-concurrency=0
+enable-experimental-distributed=0
+
+stdlib-deployment-targets=freestanding-x86_64
+swift-primary-variant-sdk=FREESTANDING
+swift-primary-variant-arch=x86_64
+swift-freestanding-flavor=apple
+swift-freestanding-sdk=macosx
+swift-freestanding-is-darwin=1
+swift-freestanding-triple-name=macosx11.0
+swift-freestanding-module-name=macos
+swift-freestanding-archs=x86_64
+
+[preset: stdlib_S_standalone_darwin_x86_64,build,test]
+mixin-preset=stdlib_S_standalone_darwin_x86_64,build
+
+test
+validation-test
 
 #===----------------------------------------------------------------------===#
 # Preset for Source Compatibility Suite

utils/build_swift/build_swift/driver_arguments.py

@@ -589,6 +589,9 @@ def create_argument_parser():
                 'module-only targets on Darwin platforms. These targets are '
                 'in addition to the full library targets.')
 
+    option('--swift-freestanding-is-darwin', toggle_true,
+           help='True if the freestanding platform is a Darwin one.')
+
     # -------------------------------------------------------------------------
     in_group('Options to select projects')
 

utils/build_swift/tests/expected_options.py

@@ -218,6 +218,7 @@
     'swift_disable_dead_stripping': False,
     'swift_darwin_module_archs': None,
     'swift_darwin_supported_archs': None,
+    'swift_freestanding_is_darwin': False,
     'swift_stdlib_assertions': True,
     'swift_stdlib_build_variant': 'Debug',
     'swift_tools_max_parallel_lto_link_jobs':
@@ -681,6 +682,7 @@ class BuildScriptImplOption(_BaseOption):
     StrOption('--stdlib-deployment-targets'),
     StrOption('--swift-darwin-module-archs'),
     StrOption('--swift-darwin-supported-archs'),
+    SetTrueOption('--swift-freestanding-is-darwin'),
 
     PathOption('--android-deploy-device-path'),
     PathOption('--android-icu-i18n'),

utils/swift_build_support/swift_build_support/products/swift.py

@@ -62,6 +62,9 @@ def __init__(self, args, toolchain, source_dir, build_dir):
         # Add experimental string processing flag.
         self.cmake_options.extend(self._enable_experimental_string_processing)
 
+        # Add freestanding related flags.
+        self.cmake_options.extend(self._freestanding_is_darwin)
+
     @classmethod
     def is_build_script_impl_product(cls):
         """is_build_script_impl_product -> bool
@@ -171,6 +174,11 @@ def _enable_experimental_string_processing(self):
         return [('SWIFT_ENABLE_EXPERIMENTAL_STRING_PROCESSING:BOOL',
                  self.args.enable_experimental_string_processing)]
 
+    @property
+    def _freestanding_is_darwin(self):
+        return [('SWIFT_FREESTANDING_IS_DARWIN:BOOL',
+                 self.args.swift_freestanding_is_darwin)]
+
     @classmethod
     def get_dependencies(cls):
         return [cmark.CMark,