1 files changed, 154 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__mutex/once_flag.h b/contrib/llvm-project/libcxx/include/__mutex/once_flag.h
new file mode 100644
index 000000000000..5a6f8e09055f
--- /dev/null
+++ b/contrib/llvm-project/libcxx/include/__mutex/once_flag.h
@@ -0,0 +1,154 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MUTEX_ONCE_FLAG_H
+#define _LIBCPP___MUTEX_ONCE_FLAG_H
+
+#include <__config>
+#include <__functional/invoke.h>
+#include <__memory/shared_ptr.h> // __libcpp_acquire_load
+#include <__tuple/tuple_indices.h>
+#include <__tuple/tuple_size.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <cstdint>
+#ifndef _LIBCPP_CXX03_LANG
+#  include <tuple>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+struct _LIBCPP_TEMPLATE_VIS once_flag;
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Callable, class... _Args>
+_LIBCPP_HIDE_FROM_ABI void call_once(once_flag&, _Callable&&, _Args&&...);
+
+#else // _LIBCPP_CXX03_LANG
+
+template <class _Callable>
+_LIBCPP_HIDE_FROM_ABI void call_once(once_flag&, _Callable&);
+
+template <class _Callable>
+_LIBCPP_HIDE_FROM_ABI void call_once(once_flag&, const _Callable&);
+
+#endif // _LIBCPP_CXX03_LANG
+
+struct _LIBCPP_TEMPLATE_VIS once_flag {
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR once_flag() _NOEXCEPT : __state_(_Unset) {}
+  once_flag(const once_flag&)            = delete;
+  once_flag& operator=(const once_flag&) = delete;
+
+#if defined(_LIBCPP_ABI_MICROSOFT)
+  typedef uintptr_t _State_type;
+#else
+  typedef unsigned long _State_type;
+#endif
+
+  static const _State_type _Unset    = 0;
+  static const _State_type _Pending  = 1;
+  static const _State_type _Complete = ~_State_type(0);
+
+private:
+  _State_type __state_;
+
+#ifndef _LIBCPP_CXX03_LANG
+  template <class _Callable, class... _Args>
+  friend void call_once(once_flag&, _Callable&&, _Args&&...);
+#else  // _LIBCPP_CXX03_LANG
+  template <class _Callable>
+  friend void call_once(once_flag&, _Callable&);
+
+  template <class _Callable>
+  friend void call_once(once_flag&, const _Callable&);
+#endif // _LIBCPP_CXX03_LANG
+};
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Fp>
+class __call_once_param {
+  _Fp& __f_;
+
+public:
+  _LIBCPP_HIDE_FROM_ABI explicit __call_once_param(_Fp& __f) : __f_(__f) {}
+
+  _LIBCPP_HIDE_FROM_ABI void operator()() {
+    typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
+    __execute(_Index());
+  }
+
+private:
+  template <size_t... _Indices>
+  _LIBCPP_HIDE_FROM_ABI void __execute(__tuple_indices<_Indices...>) {
+    std::__invoke(std::get<0>(std::move(__f_)), std::get<_Indices>(std::move(__f_))...);
+  }
+};
+
+#else
+
+template <class _Fp>
+class __call_once_param {
+  _Fp& __f_;
+
+public:
+  _LIBCPP_HIDE_FROM_ABI explicit __call_once_param(_Fp& __f) : __f_(__f) {}
+
+  _LIBCPP_HIDE_FROM_ABI void operator()() { __f_(); }
+};
+
+#endif
+
+template <class _Fp>
+void _LIBCPP_HIDE_FROM_ABI __call_once_proxy(void* __vp) {
+  __call_once_param<_Fp>* __p = static_cast<__call_once_param<_Fp>*>(__vp);
+  (*__p)();
+}
+
+_LIBCPP_EXPORTED_FROM_ABI void __call_once(volatile once_flag::_State_type&, void*, void (*)(void*));
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Callable, class... _Args>
+inline _LIBCPP_HIDE_FROM_ABI void call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args) {
+  if (__libcpp_acquire_load(&__flag.__state_) != once_flag::_Complete) {
+    typedef tuple<_Callable&&, _Args&&...> _Gp;
+    _Gp __f(std::forward<_Callable>(__func), std::forward<_Args>(__args)...);
+    __call_once_param<_Gp> __p(__f);
+    std::__call_once(__flag.__state_, &__p, &__call_once_proxy<_Gp>);
+  }
+}
+
+#else // _LIBCPP_CXX03_LANG
+
+template <class _Callable>
+inline _LIBCPP_HIDE_FROM_ABI void call_once(once_flag& __flag, _Callable& __func) {
+  if (__libcpp_acquire_load(&__flag.__state_) != once_flag::_Complete) {
+    __call_once_param<_Callable> __p(__func);
+    std::__call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
+  }
+}
+
+template <class _Callable>
+inline _LIBCPP_HIDE_FROM_ABI void call_once(once_flag& __flag, const _Callable& __func) {
+  if (__libcpp_acquire_load(&__flag.__state_) != once_flag::_Complete) {
+    __call_once_param<const _Callable> __p(__func);
+    std::__call_once(__flag.__state_, &__p, &__call_once_proxy<const _Callable>);
+  }
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MUTEX_ONCE_FLAG_H