To be able to correctly exercise Concurrency on freestanding, default to using 'pthread' threading package (#65329)

To be able to correctly exercise Concurrency on freestanding, default to using 'pthread' threading package

rdar://102259828

Author: kubamracek

stdlib/public/runtime/MetadataCache.h

@@ -174,7 +174,8 @@ class LockingConcurrentMapStorage {
   // TargetGenericMetadataInstantiationCache::PrivateData. On 32-bit archs, that
   // space is not large enough to accommodate a Mutex along with everything
   // else. There, use a SmallMutex to squeeze into the available space.
-  using MutexTy = std::conditional_t<sizeof(void *) == 8, Mutex, SmallMutex>;
+  using MutexTy = std::conditional_t<sizeof(void *) == 8 && sizeof(Mutex) <= 56,
+                                     Mutex, SmallMutex>;
   StableAddressConcurrentReadableHashMap<EntryType,
                                          TaggedMetadataAllocator<Tag>, MutexTy>
       Map;

test/Concurrency/Runtime/actor_counters_freestanding.swift

@@ -4,9 +4,6 @@
 // REQUIRES: concurrency
 // REQUIRES: freestanding
 
-// rdar://101938326
-// UNSUPPORTED: freestanding
-
 // rdar://76038845
 // REQUIRES: concurrency_runtime
 // UNSUPPORTED: back_deployment_runtime

utils/build-presets.ini

@@ -2603,7 +2603,7 @@ swift-stdlib-enable-vector-types=0
 swift-stdlib-experimental-hermetic-seal-at-link=1
 swift-stdlib-disable-instantiation-caches=1
 swift-stdlib-has-type-printing=0
-swift-threading-package=none
+swift-threading-package=pthreads
 build-swift-stdlib-unicode-data=0
 build-swift-stdlib-static-print=1
 darwin-crash-reporter-client=0

utils/check_freestanding_dependencies.py

@@ -40,6 +40,13 @@
     "_log2l", "_logf", "_logl", "_nearbyintl", "_remainder", "_remainderf",
     "_remainderl", "_rintl", "_roundl", "_sin", "_sinf", "_sinl", "_truncl",
 ]
+threading_package_dependencies = [
+    "_pthread_mutex_destroy", "_pthread_cond_broadcast",
+    "_pthread_get_stacksize_np", "_pthread_key_create", "_pthread_self",
+    "_pthread_equal", "_pthread_mutex_lock", "_pthread_getspecific",
+    "_pthread_mutex_unlock", "_pthread_cond_wait", "_pthread_setspecific",
+    "_pthread_get_stackaddr_np"
+]
 common_expected_dependencies = [
     "___bzero", "___divti3", "___error", "___stderrp", "___stdoutp",
     "___truncsfhf2", "___udivti3", "_abort", "_arc4random_buf",
@@ -97,7 +104,8 @@
         print("Error: Required dependency '{}' missing".format(symbol))
         fail = True
 
-allowlist = set(common_expected_dependencies + vendor_specific_dependencies)
+allowlist = set(common_expected_dependencies + vendor_specific_dependencies +
+                threading_package_dependencies)
 for symbol in deps:
     if symbol not in allowlist:
         print("Error: Unexpected dependency '{}'".format(symbol))