Revert "Merge pull request #42447 from al45tair/eng/PR-90776105"

This reverts commit 8bcb71140f, reversing
changes made to c4dd271d36.

lib/Threading/Pthreads.cpp

@@ -1,120 +0,0 @@
-//==--- Pthreads.cpp - Threading abstraction implementation ---- -*-C++ -*-===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2022 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-//
-// Implements threading support for plain pthreads
-//
-//===----------------------------------------------------------------------===//
-
-#if SWIFT_THREADING_PTHREADS
-
-#if defined(__FreeBSD__) || defined(__OpenBSD__)
-#include <pthread_np.h>
-#endif
-
-#include "swift/Threading/Impl.h"
-#include "swift/Threading/Errors.h"
-
-namespace {
-
-#pragma clang diagnostic push
-#pragma GCC diagnostic ignored "-Wglobal-constructors"
-
-class MainThreadRememberer {
-private:
-  pthread_t mainThread_;
-
-public:
-  MainThreadRememberer() { mainThread_ = pthread_self(); }
-
-  pthread_t main_thread() const { return mainThread_; }
-};
-
-MainThreadRememberer rememberer;
-pthread_mutex_t onceMutex = PTHREAD_MUTEX_INITIALIZER;
-pthread_cond_t onceCond = PTHREAD_COND_INITIALIZER;
-
-#pragma clang diagnostic pop
-
-} // namespace
-
-using namespace swift;
-using namespace threading_impl;
-
-bool swift::threading_impl::thread_is_main() {
-  return pthread_equal(pthread_self(), rememberer.main_thread());
-}
-
-void swift::threading_impl::once_slow(once_t &predicate, void (*fn)(void *),
-                                      void *context) {
-  std::int64_t zero = 0;
-  if (predicate.compare_exchange_strong(zero, (std::int64_t)1,
-                                        std::memory_order_relaxed,
-                                        std::memory_order_relaxed)) {
-    fn(context);
-
-    predicate.store((std::int64_t)-1, std::memory_order_release);
-
-    pthread_mutex_lock(&onceMutex);
-    pthread_mutex_unlock(&onceMutex);
-    pthread_cond_broadcast(&onceCond);
-    return;
-  }
-
-  pthread_mutex_lock(&onceMutex);
-  while (predicate.load(std::memory_order_acquire) >= (std::int64_t)0) {
-    pthread_cond_wait(&onceCond);
-  }
-  pthread_mutex_unlock(&onceMutex);
-}
-
-#if defined(__OpenBSD__)
-llvm::Optional<swift::threading_impl::stack_bounds>
-swift::threading_impl::thread_get_current_stack_bounds() {
-  stack_t sinfo;
-
-  if (!pthread_stackseg_np(pthread_self(), &sinfo)) {
-    stack_bounds result = {
-      (char *)sinfo.ss_sp - sinfo.ss_size,
-      sinfo.ss_sp
-    };
-    return result;
-  }
-
-  return {};
-}
-#else
-llvm::Optional<swift::threading_impl::stack_bounds>
-swift::threading_impl::thread_get_current_stack_bounds() {
-  pthread_attr_t attr;
-  size_t size = 0;
-  void *begin = nullptr;
-
-#if defined(__FreeBSD__)
-  if (pthread_attr_init(&attr))
-    return {};
-#endif
-
-  if (!pthread_getattr_np(pthread_self(), &attr)) {
-    if (!pthread_attr_getstack(&attr, &begin, &size)) {
-      stack_bounds result = { begin, (char *)begin + size };
-      pthread_attr_destroy(&attr);
-      return result;
-    }
-
-    pthread_attr_destroy(&attr);
-  }
-
-  return {};
-}
-#endif
-
-#endif // SWIFT_THREADING_PTHREADS