[libc++] Granularize <atomic>

[philnik]

Generate files

[philnik]

Try to fix CI

[philnik]

Try to fix CI

[philnik]

Try to fix CI

[philnik]

Try to fix CI

[philnik]

Try to fix CI

[philnik]

Rebased

[Mordante]

LGTM!
Since the patch already most likely breaks possible patches, I would suggest to do a followup patch to change some code to our current preferred style. WDYT?

libcxx/include/__atomic/aliases.h

28

Suggestion, change this to using in a NFC follow up patch.

libcxx/include/__atomic/atomic.h

37

Followup suggestion s/_LIBCPP_INLINE_VISIBILITY/_LIBCPP_HIDE_FROM_ABI/

libcxx/include/__atomic/atomic_sync.h

87

Followup suggestion s/_VSTD/std/

[philnik]

In D142972#4132999, @Mordante wrote:

LGTM!
Since the patch already most likely breaks possible patches, I would suggest to do a followup patch to change some code to our current preferred style. WDYT?

Sounds good. I'll make a few NFC patches.

[philnik]

Rebased

[philnik]

ignore format

[paulkirth]

libcxx/include/__atomic/cxx_atomic_impl.h

774

I think the use of __libcpp_is_always_lock_free requires a new #include <__atomic/is_always_lock_free.h>, doesn't it?

We're seeing some build failures after this change that appear to be caused by a missing include. If that is the case can you provide a forward fix?

Here's our error message, and a link to our failing bot.

[38461/300130](185) CXX kernel.efi_x64/obj/src/lib/utf_conversion/libutf_conversion.utf_conversion.cc.o
FAILED: kernel.efi_x64/obj/src/lib/utf_conversion/libutf_conversion.utf_conversion.cc.o
../../../recipe_cleanup/clangr8n6ja_c/bin/clang++ -MD -MF kernel.efi_x64/obj/src/lib/utf_conversion/libutf_conversion.utf_conversion.cc.o.d -o kernel.efi_x64/obj/src/lib/utf_conversion/libutf_conversion.utf_conversion.cc.o -D_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS -D_LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS=1 -DZX_ASSERT_LEVEL=2 -DWITH_FRAME_POINTERS=1 -I../../zircon/system/public -I../../sdk/lib...
In file included from ../../src/lib/utf_conversion/utf_conversion.cc:7:
In file included from ../../sdk/lib/stdcompat/include/lib/stdcompat/bit.h:12:
In file included from ../../sdk/lib/stdcompat/include/lib/stdcompat/memory.h:8:
In file included from ../../../recipe_cleanup/clangr8n6ja_c/include/c++/v1/memory:898:
In file included from ../../../recipe_cleanup/clangr8n6ja_c/include/c++/v1/__memory/shared_ptr.h:42:
In file included from ../../../recipe_cleanup/clangr8n6ja_c/include/c++/v1/atomic:522:
In file included from ../../../recipe_cleanup/clangr8n6ja_c/include/c++/v1/__atomic/aliases.h:12:
In file included from ../../../recipe_cleanup/clangr8n6ja_c/include/c++/v1/__atomic/atomic.h:12:
In file included from ../../../recipe_cleanup/clangr8n6ja_c/include/c++/v1/__atomic/atomic_base.h:12:
In file included from ../../../recipe_cleanup/clangr8n6ja_c/include/c++/v1/__atomic/atomic_sync.h:12:
In file included from ../../../recipe_cleanup/clangr8n6ja_c/include/c++/v1/__atomic/contention_t.h:12:
../../../recipe_cleanup/clangr8n6ja_c/include/c++/v1/__atomic/cxx_atomic_impl.h:773:49: error: no template named '__libcpp_is_always_lock_free'
          typename _Base = typename conditional<__libcpp_is_always_lock_free<_Tp>::__value,
                                                ^
../../../recipe_cleanup/clangr8n6ja_c/include/c++/v1/__atomic/cxx_atomic_impl.h:775:80: error: no type named 'type' in the global namespace
                                                __cxx_atomic_lock_impl<_Tp> >::type>
                                                                             ~~^
../../../recipe_cleanup/clangr8n6ja_c/include/c++/v1/__atomic/cxx_atomic_impl.h:775:84: error: expected unqualified-id
                                                __cxx_atomic_lock_impl<_Tp> >::type>

https://ci.chromium.org/ui/p/fuchsia/builders/ci/clang_toolchain.ci.core.x64-debug-tot-build_only/b8788907734054093697/overview

[philnik]

libcxx/include/__atomic/cxx_atomic_impl.h

774

Thanks for the report! I fixed it in 21a543656cf4840023078359a6c7e0db7d5391b2. We should definitely get a runner for a minimal freestanding implementation to catch these kinds of problems.

[paulkirth]

libcxx/include/__atomic/cxx_atomic_impl.h

774

Thanks for the quick fix. Fuchsia's build is a bit complex, so I wasn't 100% sure there wasn't' something wacky going on.

[paulkirth]

libcxx/include/__atomic/cxx_atomic_impl.h

774

I think this is still missing #include <__type_traits/conditional.h>

Do you have an intuition as to why these wouldn't fail in presubmit testing? AFAICT this should always be an issue w/ the new header structure. Well, at least in this code path, which seems to be a common/tested case. Are other platforms getting definitions pulled in earlier for some reason? I didn't see anything in the preprocessor logic that stood out, so I'm a bit puzzled as to why this crops up in our build more than others. The code being built is a user-land library that just pulls in standard headers, and isn't overly complex (counter to my earlier statement).

[53272/300225](640) CXX kernel.efi_x64/obj/zircon/kernel/lib/libc/libc.rand.cc.o
FAILED: kernel.efi_x64/obj/zircon/kernel/lib/libc/libc.rand.cc.o
../../../recipe_cleanup/clangmfsa2yky/bin/clang++ -MD -MF kernel.efi_x64/obj/zircon/kernel/lib/libc/libc.rand.cc.o.d -o kernel.efi_x64/obj/zircon/kernel/lib/libc/libc.rand.cc.o -D_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS -D_LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS=1 -DZX_ASSERT_LEVEL=2 -DWITH_FRAME_POINTERS=1 -I../../zircon/system/public -I../../zircon/kernel/lib/libc/include -I../../zircon/kernel/...
In file included from ../../zircon/kernel/lib/libc/rand.cc:10:
In file included from ../../zircon/kernel/lib/ktl/include/ktl/atomic.h:10:
In file included from ../../sdk/lib/stdcompat/include/lib/stdcompat/atomic.h:10:
In file included from ../../../recipe_cleanup/clangmfsa2yky/include/c++/v1/atomic:522:
In file included from ../../../recipe_cleanup/clangmfsa2yky/include/c++/v1/__atomic/aliases.h:12:
In file included from ../../../recipe_cleanup/clangmfsa2yky/include/c++/v1/__atomic/atomic.h:12:
In file included from ../../../recipe_cleanup/clangmfsa2yky/include/c++/v1/__atomic/atomic_base.h:12:
In file included from ../../../recipe_cleanup/clangmfsa2yky/include/c++/v1/__atomic/atomic_sync.h:12:
In file included from ../../../recipe_cleanup/clangmfsa2yky/include/c++/v1/__atomic/contention_t.h:12:
../../../recipe_cleanup/clangmfsa2yky/include/c++/v1/__atomic/cxx_atomic_impl.h:774:37: error: no template named 'conditional'
          typename _Base = typename conditional<__libcpp_is_always_lock_free<_Tp>::__value,

[philnik]

libcxx/include/__atomic/cxx_atomic_impl.h

774

I think we don't test _LIBCPP_ATOMIC_ONLY_USE_BUILTINS in our CI, which means this code gets never executed. I've uploaded D144307, which should hopefully fix the remaining problems. Could you apply it locally and check?

[paulkirth]

libcxx/include/__atomic/cxx_atomic_impl.h

774

sorry was commuting. it may take me a bit to spin something up and check locally, but I can give it a whirl.

[paulkirth]

libcxx/include/__atomic/cxx_atomic_impl.h

774

Seems like D144307 addresses the last of these issues from what I can see.

libcxx/include/CMakeLists.txt

set(files
   __algorithm/transform.h
   __algorithm/uniform_random_bit_generator_adaptor.h
   __algorithm/unique.h
   __algorithm/unique_copy.h
   __algorithm/unwrap_iter.h
   __algorithm/unwrap_range.h
   __algorithm/upper_bound.h
   __assert
+  __atomic/aliases.h
+  __atomic/atomic.h
+  __atomic/atomic_base.h
+  __atomic/atomic_flag.h
+  __atomic/atomic_init.h
+  __atomic/atomic_lock_free.h
+  __atomic/atomic_sync.h
+  __atomic/check_memory_order.h
+  __atomic/contention_t.h
+  __atomic/cxx_atomic_impl.h
+  __atomic/fence.h
+  __atomic/is_always_lock_free.h
+  __atomic/kill_dependency.h
+  __atomic/memory_order.h
   __availability
   __bit/bit_cast.h
   __bit/bit_ceil.h
   __bit/bit_floor.h
   __bit/bit_log2.h
   __bit/bit_width.h
   __bit/blsr.h
   __bit/byteswap.h

libcxx/include/__atomic/aliases.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_ALIASES_H
+#define _LIBCPP___ATOMIC_ALIASES_H
+
+#include <__atomic/atomic.h>
+#include <__atomic/atomic_lock_free.h>
+#include <__atomic/contention_t.h>
+#include <__atomic/is_always_lock_free.h>
+#include <__config>
+#include <__type_traits/conditional.h>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+typedef atomic<bool>               atomic_bool;
+typedef atomic<char>               atomic_char;
+typedef atomic<signed char>        atomic_schar;
+typedef atomic<unsigned char>      atomic_uchar;
+typedef atomic<short>              atomic_short;
+typedef atomic<unsigned short>     atomic_ushort;
+typedef atomic<int>                atomic_int;
+typedef atomic<unsigned int>       atomic_uint;
+typedef atomic<long>               atomic_long;
+typedef atomic<unsigned long>      atomic_ulong;
+typedef atomic<long long>          atomic_llong;
+typedef atomic<unsigned long long> atomic_ullong;
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+typedef atomic<char8_t>            atomic_char8_t;
+#endif
+typedef atomic<char16_t>           atomic_char16_t;
+typedef atomic<char32_t>           atomic_char32_t;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef atomic<wchar_t>            atomic_wchar_t;
+#endif
+
+typedef atomic<int_least8_t>   atomic_int_least8_t;
+typedef atomic<uint_least8_t>  atomic_uint_least8_t;
+typedef atomic<int_least16_t>  atomic_int_least16_t;
+typedef atomic<uint_least16_t> atomic_uint_least16_t;
+typedef atomic<int_least32_t>  atomic_int_least32_t;
+typedef atomic<uint_least32_t> atomic_uint_least32_t;
+typedef atomic<int_least64_t>  atomic_int_least64_t;
+typedef atomic<uint_least64_t> atomic_uint_least64_t;
+
+typedef atomic<int_fast8_t>   atomic_int_fast8_t;
+typedef atomic<uint_fast8_t>  atomic_uint_fast8_t;
+typedef atomic<int_fast16_t>  atomic_int_fast16_t;
+typedef atomic<uint_fast16_t> atomic_uint_fast16_t;
+typedef atomic<int_fast32_t>  atomic_int_fast32_t;
+typedef atomic<uint_fast32_t> atomic_uint_fast32_t;
+typedef atomic<int_fast64_t>  atomic_int_fast64_t;
+typedef atomic<uint_fast64_t> atomic_uint_fast64_t;
+
+typedef atomic< int8_t>  atomic_int8_t;
+typedef atomic<uint8_t>  atomic_uint8_t;
+typedef atomic< int16_t> atomic_int16_t;
+typedef atomic<uint16_t> atomic_uint16_t;
+typedef atomic< int32_t> atomic_int32_t;
+typedef atomic<uint32_t> atomic_uint32_t;
+typedef atomic< int64_t> atomic_int64_t;
+typedef atomic<uint64_t> atomic_uint64_t;
+
+typedef atomic<intptr_t>  atomic_intptr_t;
+typedef atomic<uintptr_t> atomic_uintptr_t;
+typedef atomic<size_t>    atomic_size_t;
+typedef atomic<ptrdiff_t> atomic_ptrdiff_t;
+typedef atomic<intmax_t>  atomic_intmax_t;
+typedef atomic<uintmax_t> atomic_uintmax_t;
+
+// atomic_*_lock_free : prefer the contention type most highly, then the largest lock-free type
+
+#ifdef __cpp_lib_atomic_is_always_lock_free
+# define _LIBCPP_CONTENTION_LOCK_FREE ::std::__libcpp_is_always_lock_free<__cxx_contention_t>::__value
+#else
+# define _LIBCPP_CONTENTION_LOCK_FREE false
+#endif
+
+#if ATOMIC_LLONG_LOCK_FREE == 2
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, long long>          __libcpp_signed_lock_free;
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned long long> __libcpp_unsigned_lock_free;
+#elif ATOMIC_INT_LOCK_FREE == 2
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, int>                __libcpp_signed_lock_free;
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned int>       __libcpp_unsigned_lock_free;
+#elif ATOMIC_SHORT_LOCK_FREE == 2
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, short>              __libcpp_signed_lock_free;
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned short>     __libcpp_unsigned_lock_free;
+#elif ATOMIC_CHAR_LOCK_FREE == 2
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, char>               __libcpp_signed_lock_free;
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned char>      __libcpp_unsigned_lock_free;
+#else
+    // No signed/unsigned lock-free types
+#define _LIBCPP_NO_LOCK_FREE_TYPES
+#endif
+
+#if !defined(_LIBCPP_NO_LOCK_FREE_TYPES)
+typedef atomic<__libcpp_signed_lock_free> atomic_signed_lock_free;
+typedef atomic<__libcpp_unsigned_lock_free> atomic_unsigned_lock_free;
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ATOMIC_ALIASES_H

libcxx/include/__atomic/atomic.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_ATOMIC_H
+#define _LIBCPP___ATOMIC_ATOMIC_H
+
+#include <__atomic/atomic_base.h>
+#include <__atomic/check_memory_order.h>
+#include <__atomic/cxx_atomic_impl.h>
+#include <__atomic/memory_order.h>
+#include <__config>
+#include <__type_traits/is_function.h>
+#include <__type_traits/is_same.h>
+#include <__type_traits/remove_pointer.h>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+struct atomic
+    : public __atomic_base<_Tp>
+{
+    typedef __atomic_base<_Tp> __base;
+    typedef _Tp value_type;
+    typedef value_type difference_type;
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    atomic() = default;
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    atomic() _NOEXCEPT = default;
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR atomic(_Tp __d) _NOEXCEPT : __base(__d) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator=(_Tp __d) volatile _NOEXCEPT
+        {__base::store(__d); return __d;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator=(_Tp __d) _NOEXCEPT
+        {__base::store(__d); return __d;}
+
+    atomic& operator=(const atomic&) = delete;
+    atomic& operator=(const atomic&) volatile = delete;
+};
+
+// atomic<T*>
+
+template <class _Tp>
+struct atomic<_Tp*>
+    : public __atomic_base<_Tp*>
+{
+    typedef __atomic_base<_Tp*> __base;
+    typedef _Tp* value_type;
+    typedef ptrdiff_t difference_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    atomic() _NOEXCEPT = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR atomic(_Tp* __d) _NOEXCEPT : __base(__d) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator=(_Tp* __d) volatile _NOEXCEPT
+        {__base::store(__d); return __d;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator=(_Tp* __d) _NOEXCEPT
+        {__base::store(__d); return __d;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT {
+        // __atomic_fetch_add accepts function pointers, guard against them.
+        static_assert(!is_function<__remove_pointer_t<_Tp> >::value, "Pointer to function isn't allowed");
+        return std::__cxx_atomic_fetch_add(&this->__a_, __op, __m);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT {
+        // __atomic_fetch_add accepts function pointers, guard against them.
+        static_assert(!is_function<__remove_pointer_t<_Tp> >::value, "Pointer to function isn't allowed");
+        return std::__cxx_atomic_fetch_add(&this->__a_, __op, __m);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT {
+        // __atomic_fetch_add accepts function pointers, guard against them.
+        static_assert(!is_function<__remove_pointer_t<_Tp> >::value, "Pointer to function isn't allowed");
+        return std::__cxx_atomic_fetch_sub(&this->__a_, __op, __m);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT {
+        // __atomic_fetch_add accepts function pointers, guard against them.
+        static_assert(!is_function<__remove_pointer_t<_Tp> >::value, "Pointer to function isn't allowed");
+        return std::__cxx_atomic_fetch_sub(&this->__a_, __op, __m);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator++(int) volatile _NOEXCEPT            {return fetch_add(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator++(int) _NOEXCEPT                     {return fetch_add(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator--(int) volatile _NOEXCEPT            {return fetch_sub(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator--(int) _NOEXCEPT                     {return fetch_sub(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator++() volatile _NOEXCEPT               {return fetch_add(1) + 1;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator++() _NOEXCEPT                        {return fetch_add(1) + 1;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator--() volatile _NOEXCEPT               {return fetch_sub(1) - 1;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator--() _NOEXCEPT                        {return fetch_sub(1) - 1;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator+=(ptrdiff_t __op) volatile _NOEXCEPT {return fetch_add(__op) + __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator+=(ptrdiff_t __op) _NOEXCEPT          {return fetch_add(__op) + __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator-=(ptrdiff_t __op) volatile _NOEXCEPT {return fetch_sub(__op) - __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator-=(ptrdiff_t __op) _NOEXCEPT          {return fetch_sub(__op) - __op;}
+
+    atomic& operator=(const atomic&) = delete;
+    atomic& operator=(const atomic&) volatile = delete;
+};
+
+// atomic_is_lock_free
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_is_lock_free(const volatile atomic<_Tp>* __o) _NOEXCEPT
+{
+    return __o->is_lock_free();
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_is_lock_free(const atomic<_Tp>* __o) _NOEXCEPT
+{
+    return __o->is_lock_free();
+}
+
+// atomic_init
+
+template <class _Tp>
+_LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_INLINE_VISIBILITY
+void
+atomic_init(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    std::__cxx_atomic_init(&__o->__a_, __d);
+}
+
+template <class _Tp>
+_LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_INLINE_VISIBILITY
+void
+atomic_init(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    std::__cxx_atomic_init(&__o->__a_, __d);
+}
+
+// atomic_store
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void
+atomic_store(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    __o->store(__d);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void
+atomic_store(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    __o->store(__d);
+}
+
+// atomic_store_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void
+atomic_store_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
+  _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
+{
+    __o->store(__d, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void
+atomic_store_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
+  _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
+{
+    __o->store(__d, __m);
+}
+
+// atomic_load
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_load(const volatile atomic<_Tp>* __o) _NOEXCEPT
+{
+    return __o->load();
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_load(const atomic<_Tp>* __o) _NOEXCEPT
+{
+    return __o->load();
+}
+
+// atomic_load_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_load_explicit(const volatile atomic<_Tp>* __o, memory_order __m) _NOEXCEPT
+  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
+{
+    return __o->load(__m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_load_explicit(const atomic<_Tp>* __o, memory_order __m) _NOEXCEPT
+  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
+{
+    return __o->load(__m);
+}
+
+// atomic_exchange
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_exchange(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    return __o->exchange(__d);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_exchange(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    return __o->exchange(__d);
+}
+
+// atomic_exchange_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_exchange_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
+{
+    return __o->exchange(__d, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_exchange_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
+{
+    return __o->exchange(__d, __m);
+}
+
+// atomic_compare_exchange_weak
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_weak(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    return __o->compare_exchange_weak(*__e, __d);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_weak(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    return __o->compare_exchange_weak(*__e, __d);
+}
+
+// atomic_compare_exchange_strong
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_strong(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    return __o->compare_exchange_strong(*__e, __d);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_strong(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    return __o->compare_exchange_strong(*__e, __d);
+}
+
+// atomic_compare_exchange_weak_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_weak_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e,
+                                      typename atomic<_Tp>::value_type __d,
+                                      memory_order __s, memory_order __f) _NOEXCEPT
+  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+{
+    return __o->compare_exchange_weak(*__e, __d, __s, __f);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_weak_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d,
+                                      memory_order __s, memory_order __f) _NOEXCEPT
+  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+{
+    return __o->compare_exchange_weak(*__e, __d, __s, __f);
+}
+
+// atomic_compare_exchange_strong_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_strong_explicit(volatile atomic<_Tp>* __o,
+                                        typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d,
+                                        memory_order __s, memory_order __f) _NOEXCEPT
+  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+{
+    return __o->compare_exchange_strong(*__e, __d, __s, __f);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_strong_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e,
+                                        typename atomic<_Tp>::value_type __d,
+                                        memory_order __s, memory_order __f) _NOEXCEPT
+  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+{
+    return __o->compare_exchange_strong(*__e, __d, __s, __f);
+}
+
+// atomic_wait
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_wait(const volatile atomic<_Tp>* __o,
+                 typename atomic<_Tp>::value_type __v) _NOEXCEPT
+{
+    return __o->wait(__v);
+}
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_wait(const atomic<_Tp>* __o,
+                 typename atomic<_Tp>::value_type __v) _NOEXCEPT
+{
+    return __o->wait(__v);
+}
+
+// atomic_wait_explicit
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_wait_explicit(const volatile atomic<_Tp>* __o,
+                          typename atomic<_Tp>::value_type __v,
+                          memory_order __m) _NOEXCEPT
+  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
+{
+    return __o->wait(__v, __m);
+}
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_wait_explicit(const atomic<_Tp>* __o,
+                          typename atomic<_Tp>::value_type __v,
+                          memory_order __m) _NOEXCEPT
+  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
+{
+    return __o->wait(__v, __m);
+}
+
+// atomic_notify_one
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_notify_one(volatile atomic<_Tp>* __o) _NOEXCEPT
+{
+    __o->notify_one();
+}
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_notify_one(atomic<_Tp>* __o) _NOEXCEPT
+{
+    __o->notify_one();
+}
+
+// atomic_notify_all
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_notify_all(volatile atomic<_Tp>* __o) _NOEXCEPT
+{
+    __o->notify_all();
+}
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_notify_all(atomic<_Tp>* __o) _NOEXCEPT
+{
+    __o->notify_all();
+}
+
+// atomic_fetch_add
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_fetch_add(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
+{
+    return __o->fetch_add(__op);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_fetch_add(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
+{
+    return __o->fetch_add(__op);
+}
+
+// atomic_fetch_add_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp atomic_fetch_add_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_add(__op, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp atomic_fetch_add_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_add(__op, __m);
+}
+
+// atomic_fetch_sub
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp atomic_fetch_sub(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
+{
+    return __o->fetch_sub(__op);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp atomic_fetch_sub(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
+{
+    return __o->fetch_sub(__op);
+}
+
+// atomic_fetch_sub_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp atomic_fetch_sub_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_sub(__op, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp atomic_fetch_sub_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_sub(__op, __m);
+}
+
+// atomic_fetch_and
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_and(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
+{
+    return __o->fetch_and(__op);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_and(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
+{
+    return __o->fetch_and(__op);
+}
+
+// atomic_fetch_and_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_and_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_and(__op, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_and_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_and(__op, __m);
+}
+
+// atomic_fetch_or
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_or(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
+{
+    return __o->fetch_or(__op);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_or(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
+{
+    return __o->fetch_or(__op);
+}
+
+// atomic_fetch_or_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_or_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_or(__op, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_or_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_or(__op, __m);
+}
+
+// atomic_fetch_xor
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_xor(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
+{
+    return __o->fetch_xor(__op);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_xor(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
+{
+    return __o->fetch_xor(__op);
+}
+
+// atomic_fetch_xor_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_xor_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_xor(__op, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_xor_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_xor(__op, __m);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ATOMIC_ATOMIC_H

libcxx/include/__atomic/atomic_base.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_ATOMIC_BASE_H
+#define _LIBCPP___ATOMIC_ATOMIC_BASE_H
+
+#include <__atomic/atomic_sync.h>
+#include <__atomic/check_memory_order.h>
+#include <__atomic/cxx_atomic_impl.h>
+#include <__atomic/is_always_lock_free.h>
+#include <__atomic/memory_order.h>
+#include <__availability>
+#include <__config>
+#include <__type_traits/is_integral.h>
+#include <__type_traits/is_nothrow_default_constructible.h>
+#include <__type_traits/is_same.h>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, bool = is_integral<_Tp>::value && !is_same<_Tp, bool>::value>
+struct __atomic_base  // false
+{
+    mutable __cxx_atomic_impl<_Tp> __a_;
+
+#if defined(__cpp_lib_atomic_is_always_lock_free)
+  static _LIBCPP_CONSTEXPR bool is_always_lock_free = __libcpp_is_always_lock_free<__cxx_atomic_impl<_Tp> >::__value;
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool is_lock_free() const volatile _NOEXCEPT
+        {return __cxx_atomic_is_lock_free(sizeof(_Tp));}
+    _LIBCPP_INLINE_VISIBILITY
+    bool is_lock_free() const _NOEXCEPT
+        {return static_cast<__atomic_base const volatile*>(this)->is_lock_free();}
+    _LIBCPP_INLINE_VISIBILITY
+    void store(_Tp __d, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+      _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
+        {std::__cxx_atomic_store(&__a_, __d, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    void store(_Tp __d, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+      _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
+        {std::__cxx_atomic_store(&__a_, __d, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp load(memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
+      _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
+        {return std::__cxx_atomic_load(&__a_, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp load(memory_order __m = memory_order_seq_cst) const _NOEXCEPT
+      _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
+        {return std::__cxx_atomic_load(&__a_, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    operator _Tp() const volatile _NOEXCEPT {return load();}
+    _LIBCPP_INLINE_VISIBILITY
+    operator _Tp() const _NOEXCEPT          {return load();}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return std::__cxx_atomic_exchange(&__a_, __d, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return std::__cxx_atomic_exchange(&__a_, __d, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_weak(_Tp& __e, _Tp __d,
+                               memory_order __s, memory_order __f) volatile _NOEXCEPT
+      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+        {return std::__cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_weak(_Tp& __e, _Tp __d,
+                               memory_order __s, memory_order __f) _NOEXCEPT
+      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+        {return std::__cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_strong(_Tp& __e, _Tp __d,
+                                 memory_order __s, memory_order __f) volatile _NOEXCEPT
+      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+        {return std::__cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_strong(_Tp& __e, _Tp __d,
+                                 memory_order __s, memory_order __f) _NOEXCEPT
+      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+        {return std::__cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_weak(_Tp& __e, _Tp __d,
+                              memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return std::__cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_weak(_Tp& __e, _Tp __d,
+                               memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return std::__cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_strong(_Tp& __e, _Tp __d,
+                              memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return std::__cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_strong(_Tp& __e, _Tp __d,
+                                 memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return std::__cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
+
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void wait(_Tp __v, memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
+        {std::__cxx_atomic_wait(&__a_, __v, __m);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void wait(_Tp __v, memory_order __m = memory_order_seq_cst) const _NOEXCEPT
+        {std::__cxx_atomic_wait(&__a_, __v, __m);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_one() volatile _NOEXCEPT
+        {std::__cxx_atomic_notify_one(&__a_);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_one() _NOEXCEPT
+        {std::__cxx_atomic_notify_one(&__a_);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_all() volatile _NOEXCEPT
+        {std::__cxx_atomic_notify_all(&__a_);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_all() _NOEXCEPT
+        {std::__cxx_atomic_notify_all(&__a_);}
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY constexpr
+    __atomic_base() noexcept(is_nothrow_default_constructible_v<_Tp>) : __a_(_Tp()) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    __atomic_base() _NOEXCEPT = default;
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    __atomic_base(_Tp __d) _NOEXCEPT : __a_(__d) {}
+
+    __atomic_base(const __atomic_base&) = delete;
+};
+
+#if defined(__cpp_lib_atomic_is_always_lock_free)
+template <class _Tp, bool __b>
+_LIBCPP_CONSTEXPR bool __atomic_base<_Tp, __b>::is_always_lock_free;
+#endif
+
+// atomic<Integral>
+
+template <class _Tp>
+struct __atomic_base<_Tp, true>
+    : public __atomic_base<_Tp, false>
+{
+    typedef __atomic_base<_Tp, false> __base;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+    __atomic_base() _NOEXCEPT = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR __atomic_base(_Tp __d) _NOEXCEPT : __base(__d) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return std::__cxx_atomic_fetch_add(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return std::__cxx_atomic_fetch_add(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return std::__cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return std::__cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return std::__cxx_atomic_fetch_and(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return std::__cxx_atomic_fetch_and(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return std::__cxx_atomic_fetch_or(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return std::__cxx_atomic_fetch_or(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return std::__cxx_atomic_fetch_xor(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return std::__cxx_atomic_fetch_xor(&this->__a_, __op, __m);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator++(int) volatile _NOEXCEPT      {return fetch_add(_Tp(1));}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator++(int) _NOEXCEPT               {return fetch_add(_Tp(1));}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator--(int) volatile _NOEXCEPT      {return fetch_sub(_Tp(1));}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator--(int) _NOEXCEPT               {return fetch_sub(_Tp(1));}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator++() volatile _NOEXCEPT         {return fetch_add(_Tp(1)) + _Tp(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator++() _NOEXCEPT                  {return fetch_add(_Tp(1)) + _Tp(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator--() volatile _NOEXCEPT         {return fetch_sub(_Tp(1)) - _Tp(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator--() _NOEXCEPT                  {return fetch_sub(_Tp(1)) - _Tp(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator+=(_Tp __op) volatile _NOEXCEPT {return fetch_add(__op) + __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator+=(_Tp __op) _NOEXCEPT          {return fetch_add(__op) + __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator-=(_Tp __op) volatile _NOEXCEPT {return fetch_sub(__op) - __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator-=(_Tp __op) _NOEXCEPT          {return fetch_sub(__op) - __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator&=(_Tp __op) volatile _NOEXCEPT {return fetch_and(__op) & __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator&=(_Tp __op) _NOEXCEPT          {return fetch_and(__op) & __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator|=(_Tp __op) volatile _NOEXCEPT {return fetch_or(__op) | __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator|=(_Tp __op) _NOEXCEPT          {return fetch_or(__op) | __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator^=(_Tp __op) volatile _NOEXCEPT {return fetch_xor(__op) ^ __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator^=(_Tp __op) _NOEXCEPT          {return fetch_xor(__op) ^ __op;}
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ATOMIC_ATOMIC_BASE_H

libcxx/include/__atomic/atomic_flag.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_ATOMIC_FLAG_H
+#define _LIBCPP___ATOMIC_ATOMIC_FLAG_H
+
+#include <__atomic/atomic_sync.h>
+#include <__atomic/contention_t.h>
+#include <__atomic/cxx_atomic_impl.h>
+#include <__atomic/memory_order.h>
+#include <__chrono/duration.h>
+#include <__config>
+#include <__threading_support>
+#include <cstdint>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+typedef struct atomic_flag
+{
+    __cxx_atomic_impl<_LIBCPP_ATOMIC_FLAG_TYPE> __a_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool test(memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
+        {return _LIBCPP_ATOMIC_FLAG_TYPE(true) == __cxx_atomic_load(&__a_, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool test(memory_order __m = memory_order_seq_cst) const _NOEXCEPT
+        {return _LIBCPP_ATOMIC_FLAG_TYPE(true) == __cxx_atomic_load(&__a_, __m);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool test_and_set(memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool test_and_set(memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear(memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear(memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
+
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void wait(bool __v, memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
+        {__cxx_atomic_wait(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(__v), __m);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void wait(bool __v, memory_order __m = memory_order_seq_cst) const _NOEXCEPT
+        {__cxx_atomic_wait(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(__v), __m);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void notify_one() volatile _NOEXCEPT
+        {__cxx_atomic_notify_one(&__a_);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void notify_one() _NOEXCEPT
+        {__cxx_atomic_notify_one(&__a_);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void notify_all() volatile _NOEXCEPT
+        {__cxx_atomic_notify_all(&__a_);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void notify_all() _NOEXCEPT
+        {__cxx_atomic_notify_all(&__a_);}
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY constexpr
+    atomic_flag() _NOEXCEPT : __a_(false) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    atomic_flag() _NOEXCEPT = default;
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    atomic_flag(bool __b) _NOEXCEPT : __a_(__b) {} // EXTENSION
+
+    atomic_flag(const atomic_flag&) = delete;
+    atomic_flag& operator=(const atomic_flag&) = delete;
+    atomic_flag& operator=(const atomic_flag&) volatile = delete;
+
+} atomic_flag;
+
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test(const volatile atomic_flag* __o) _NOEXCEPT
+{
+    return __o->test();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test(const atomic_flag* __o) _NOEXCEPT
+{
+    return __o->test();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test_explicit(const volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
+{
+    return __o->test(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test_explicit(const atomic_flag* __o, memory_order __m) _NOEXCEPT
+{
+    return __o->test(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test_and_set(volatile atomic_flag* __o) _NOEXCEPT
+{
+    return __o->test_and_set();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test_and_set(atomic_flag* __o) _NOEXCEPT
+{
+    return __o->test_and_set();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test_and_set_explicit(volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
+{
+    return __o->test_and_set(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test_and_set_explicit(atomic_flag* __o, memory_order __m) _NOEXCEPT
+{
+    return __o->test_and_set(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+atomic_flag_clear(volatile atomic_flag* __o) _NOEXCEPT
+{
+    __o->clear();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+atomic_flag_clear(atomic_flag* __o) _NOEXCEPT
+{
+    __o->clear();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+atomic_flag_clear_explicit(volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
+{
+    __o->clear(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+atomic_flag_clear_explicit(atomic_flag* __o, memory_order __m) _NOEXCEPT
+{
+    __o->clear(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_wait(const volatile atomic_flag* __o, bool __v) _NOEXCEPT
+{
+    __o->wait(__v);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_wait(const atomic_flag* __o, bool __v) _NOEXCEPT
+{
+    __o->wait(__v);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_wait_explicit(const volatile atomic_flag* __o,
+                          bool __v, memory_order __m) _NOEXCEPT
+{
+    __o->wait(__v, __m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_wait_explicit(const atomic_flag* __o,
+                          bool __v, memory_order __m) _NOEXCEPT
+{
+    __o->wait(__v, __m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_notify_one(volatile atomic_flag* __o) _NOEXCEPT
+{
+    __o->notify_one();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_notify_one(atomic_flag* __o) _NOEXCEPT
+{
+    __o->notify_one();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_notify_all(volatile atomic_flag* __o) _NOEXCEPT
+{
+    __o->notify_all();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_notify_all(atomic_flag* __o) _NOEXCEPT
+{
+    __o->notify_all();
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ATOMIC_ATOMIC_FLAG_H

libcxx/include/__atomic/atomic_init.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_ATOMIC_INIT_H
+#define _LIBCPP___ATOMIC_ATOMIC_INIT_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#define ATOMIC_FLAG_INIT {false}
+#define ATOMIC_VAR_INIT(__v) {__v}
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS)
+# if defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER >= 1400
+#  pragma clang deprecated(ATOMIC_VAR_INIT)
+# endif
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS)
+
+#endif // _LIBCPP___ATOMIC_ATOMIC_INIT_H

libcxx/include/__atomic/atomic_lock_free.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_ATOMIC_LOCK_FREE_H
+#define _LIBCPP___ATOMIC_ATOMIC_LOCK_FREE_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if defined(__CLANG_ATOMIC_BOOL_LOCK_FREE)
+# define ATOMIC_BOOL_LOCK_FREE      __CLANG_ATOMIC_BOOL_LOCK_FREE
+# define ATOMIC_CHAR_LOCK_FREE      __CLANG_ATOMIC_CHAR_LOCK_FREE
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+# define ATOMIC_CHAR8_T_LOCK_FREE   __CLANG_ATOMIC_CHAR8_T_LOCK_FREE
+#endif
+# define ATOMIC_CHAR16_T_LOCK_FREE  __CLANG_ATOMIC_CHAR16_T_LOCK_FREE
+# define ATOMIC_CHAR32_T_LOCK_FREE  __CLANG_ATOMIC_CHAR32_T_LOCK_FREE
+# define ATOMIC_WCHAR_T_LOCK_FREE   __CLANG_ATOMIC_WCHAR_T_LOCK_FREE
+# define ATOMIC_SHORT_LOCK_FREE     __CLANG_ATOMIC_SHORT_LOCK_FREE
+# define ATOMIC_INT_LOCK_FREE       __CLANG_ATOMIC_INT_LOCK_FREE
+# define ATOMIC_LONG_LOCK_FREE      __CLANG_ATOMIC_LONG_LOCK_FREE
+# define ATOMIC_LLONG_LOCK_FREE     __CLANG_ATOMIC_LLONG_LOCK_FREE
+# define ATOMIC_POINTER_LOCK_FREE   __CLANG_ATOMIC_POINTER_LOCK_FREE
+#elif defined(__GCC_ATOMIC_BOOL_LOCK_FREE)
+# define ATOMIC_BOOL_LOCK_FREE      __GCC_ATOMIC_BOOL_LOCK_FREE
+# define ATOMIC_CHAR_LOCK_FREE      __GCC_ATOMIC_CHAR_LOCK_FREE
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+# define ATOMIC_CHAR8_T_LOCK_FREE   __GCC_ATOMIC_CHAR8_T_LOCK_FREE
+#endif
+# define ATOMIC_CHAR16_T_LOCK_FREE  __GCC_ATOMIC_CHAR16_T_LOCK_FREE
+# define ATOMIC_CHAR32_T_LOCK_FREE  __GCC_ATOMIC_CHAR32_T_LOCK_FREE
+# define ATOMIC_WCHAR_T_LOCK_FREE   __GCC_ATOMIC_WCHAR_T_LOCK_FREE
+# define ATOMIC_SHORT_LOCK_FREE     __GCC_ATOMIC_SHORT_LOCK_FREE
+# define ATOMIC_INT_LOCK_FREE       __GCC_ATOMIC_INT_LOCK_FREE
+# define ATOMIC_LONG_LOCK_FREE      __GCC_ATOMIC_LONG_LOCK_FREE
+# define ATOMIC_LLONG_LOCK_FREE     __GCC_ATOMIC_LLONG_LOCK_FREE
+# define ATOMIC_POINTER_LOCK_FREE   __GCC_ATOMIC_POINTER_LOCK_FREE
+#endif
+
+#endif // _LIBCPP___ATOMIC_ATOMIC_LOCK_FREE_H

libcxx/include/__atomic/atomic_sync.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_ATOMIC_SYNC_H
+#define _LIBCPP___ATOMIC_ATOMIC_SYNC_H
+
+#include <__atomic/contention_t.h>
+#include <__atomic/cxx_atomic_impl.h>
+#include <__atomic/memory_order.h>
+#include <__availability>
+#include <__chrono/duration.h>
+#include <__config>
+#include <__thread/poll_with_backoff.h>
+#include <__threading_support>
+#include <__type_traits/decay.h>
+#include <cstring>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(void const volatile*);
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(void const volatile*);
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t __libcpp_atomic_monitor(void const volatile*);
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __libcpp_atomic_wait(void const volatile*, __cxx_contention_t);
+
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(__cxx_atomic_contention_t const volatile*);
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(__cxx_atomic_contention_t const volatile*);
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t __libcpp_atomic_monitor(__cxx_atomic_contention_t const volatile*);
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __libcpp_atomic_wait(__cxx_atomic_contention_t const volatile*, __cxx_contention_t);
+
+template <class _Atp, class _Fn>
+struct __libcpp_atomic_wait_backoff_impl {
+    _Atp* __a;
+    _Fn __test_fn;
+    _LIBCPP_AVAILABILITY_SYNC
+    _LIBCPP_INLINE_VISIBILITY bool operator()(chrono::nanoseconds __elapsed) const
+    {
+        if(__elapsed > chrono::microseconds(64))
+        {
+            auto const __monitor = std::__libcpp_atomic_monitor(__a);
+            if(__test_fn())
+                return true;
+            std::__libcpp_atomic_wait(__a, __monitor);
+        }
+        else if(__elapsed > chrono::microseconds(4))
+            __libcpp_thread_yield();
+        else
+            {} // poll
+        return false;
+    }
+};
+
+template <class _Atp, class _Fn>
+_LIBCPP_AVAILABILITY_SYNC
+_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp* __a, _Fn && __test_fn)
+{
+    __libcpp_atomic_wait_backoff_impl<_Atp, typename decay<_Fn>::type> __backoff_fn = {__a, __test_fn};
+    return std::__libcpp_thread_poll_with_backoff(__test_fn, __backoff_fn);
+}
+
+#else // _LIBCPP_HAS_NO_THREADS
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY void __cxx_atomic_notify_all(__cxx_atomic_impl<_Tp> const volatile*) { }
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY void __cxx_atomic_notify_one(__cxx_atomic_impl<_Tp> const volatile*) { }
+template <class _Atp, class _Fn>
+_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp*, _Fn && __test_fn)
+{
+    return __libcpp_thread_poll_with_backoff(__test_fn, __spinning_backoff_policy());
+}
+
+#endif // _LIBCPP_HAS_NO_THREADS
+
+template <typename _Tp> _LIBCPP_INLINE_VISIBILITY
+bool __cxx_nonatomic_compare_equal(_Tp const& __lhs, _Tp const& __rhs) {
+    return _VSTD::memcmp(&__lhs, &__rhs, sizeof(_Tp)) == 0;
+}
+
+template <class _Atp, class _Tp>
+struct __cxx_atomic_wait_test_fn_impl {
+    _Atp* __a;
+    _Tp __val;
+    memory_order __order;
+    _LIBCPP_INLINE_VISIBILITY bool operator()() const
+    {
+        return !std::__cxx_nonatomic_compare_equal(std::__cxx_atomic_load(__a, __order), __val);
+    }
+};
+
+template <class _Atp, class _Tp>
+_LIBCPP_AVAILABILITY_SYNC
+_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp* __a, _Tp const __val, memory_order __order)
+{
+    __cxx_atomic_wait_test_fn_impl<_Atp, _Tp> __test_fn = {__a, __val, __order};
+    return std::__cxx_atomic_wait(__a, __test_fn);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ATOMIC_ATOMIC_SYNC_H

libcxx/include/__atomic/check_memory_order.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_CHECK_MEMORY_ORDER_H
+#define _LIBCPP___ATOMIC_CHECK_MEMORY_ORDER_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#define _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m) \
+  _LIBCPP_DIAGNOSE_WARNING(__m == memory_order_consume || \
+                           __m == memory_order_acquire || \
+                           __m == memory_order_acq_rel,   \
+                        "memory order argument to atomic operation is invalid")
+
+#define _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m) \
+  _LIBCPP_DIAGNOSE_WARNING(__m == memory_order_release || \
+                           __m == memory_order_acq_rel,   \
+                        "memory order argument to atomic operation is invalid")
+
+#define _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__m, __f) \
+  _LIBCPP_DIAGNOSE_WARNING(__f == memory_order_release || \
+                           __f == memory_order_acq_rel,   \
+                        "memory order argument to atomic operation is invalid")
+
+#endif // _LIBCPP___ATOMIC_CHECK_MEMORY_ORDER_H

libcxx/include/__atomic/contention_t.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_CONTENTION_T_H
+#define _LIBCPP___ATOMIC_CONTENTION_T_H
+
+#include <__atomic/cxx_atomic_impl.h>
+#include <__config>
+#include <cstdint>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if defined(__linux__) || (defined(_AIX) && !defined(__64BIT__))
+    using __cxx_contention_t = int32_t;
+#else
+    using __cxx_contention_t = int64_t;
+#endif // __linux__ || (_AIX && !__64BIT__)
+
+using __cxx_atomic_contention_t = __cxx_atomic_impl<__cxx_contention_t>;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ATOMIC_CONTENTION_T_H

libcxx/include/__atomic/cxx_atomic_impl.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_CXX_ATOMIC_IMPL_H
+#define _LIBCPP___ATOMIC_CXX_ATOMIC_IMPL_H
+
+#include <__atomic/memory_order.h>
+#include <__config>
+#include <__type_traits/is_assignable.h>
+#include <__type_traits/is_trivially_copyable.h>
+#include <__type_traits/remove_const.h>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if defined(_LIBCPP_HAS_GCC_ATOMIC_IMP) || \
+    defined(_LIBCPP_ATOMIC_ONLY_USE_BUILTINS)
+
+// [atomics.types.generic]p1 guarantees _Tp is trivially copyable. Because
+// the default operator= in an object is not volatile, a byte-by-byte copy
+// is required.
+template <typename _Tp, typename _Tv> _LIBCPP_INLINE_VISIBILITY
+typename enable_if<is_assignable<_Tp&, _Tv>::value>::type
+__cxx_atomic_assign_volatile(_Tp& __a_value, _Tv const& __val) {
+  __a_value = __val;
+}
+template <typename _Tp, typename _Tv> _LIBCPP_INLINE_VISIBILITY
+typename enable_if<is_assignable<_Tp&, _Tv>::value>::type
+__cxx_atomic_assign_volatile(_Tp volatile& __a_value, _Tv volatile const& __val) {
+  volatile char* __to = reinterpret_cast<volatile char*>(&__a_value);
+  volatile char* __end = __to + sizeof(_Tp);
+  volatile const char* __from = reinterpret_cast<volatile const char*>(&__val);
+  while (__to != __end)
+    *__to++ = *__from++;
+}
+
+#endif
+
+#if defined(_LIBCPP_HAS_GCC_ATOMIC_IMP)
+
+template <typename _Tp>
+struct __cxx_atomic_base_impl {
+
+  _LIBCPP_INLINE_VISIBILITY
+#ifndef _LIBCPP_CXX03_LANG
+    __cxx_atomic_base_impl() _NOEXCEPT = default;
+#else
+    __cxx_atomic_base_impl() _NOEXCEPT : __a_value() {}
+#endif // _LIBCPP_CXX03_LANG
+  _LIBCPP_CONSTEXPR explicit __cxx_atomic_base_impl(_Tp value) _NOEXCEPT
+    : __a_value(value) {}
+  _Tp __a_value;
+};
+
+_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR int __to_gcc_order(memory_order __order) {
+  // Avoid switch statement to make this a constexpr.
+  return __order == memory_order_relaxed ? __ATOMIC_RELAXED:
+         (__order == memory_order_acquire ? __ATOMIC_ACQUIRE:
+          (__order == memory_order_release ? __ATOMIC_RELEASE:
+           (__order == memory_order_seq_cst ? __ATOMIC_SEQ_CST:
+            (__order == memory_order_acq_rel ? __ATOMIC_ACQ_REL:
+              __ATOMIC_CONSUME))));
+}
+
+_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR int __to_gcc_failure_order(memory_order __order) {
+  // Avoid switch statement to make this a constexpr.
+  return __order == memory_order_relaxed ? __ATOMIC_RELAXED:
+         (__order == memory_order_acquire ? __ATOMIC_ACQUIRE:
+          (__order == memory_order_release ? __ATOMIC_RELAXED:
+           (__order == memory_order_seq_cst ? __ATOMIC_SEQ_CST:
+            (__order == memory_order_acq_rel ? __ATOMIC_ACQUIRE:
+              __ATOMIC_CONSUME))));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_init(volatile __cxx_atomic_base_impl<_Tp>* __a,  _Tp __val) {
+  __cxx_atomic_assign_volatile(__a->__a_value, __val);
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp>* __a,  _Tp __val) {
+  __a->__a_value = __val;
+}
+
+_LIBCPP_INLINE_VISIBILITY inline
+void __cxx_atomic_thread_fence(memory_order __order) {
+  __atomic_thread_fence(__to_gcc_order(__order));
+}
+
+_LIBCPP_INLINE_VISIBILITY inline
+void __cxx_atomic_signal_fence(memory_order __order) {
+  __atomic_signal_fence(__to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_store(volatile __cxx_atomic_base_impl<_Tp>* __a,  _Tp __val,
+                        memory_order __order) {
+  __atomic_store(&__a->__a_value, &__val,
+                 __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp>* __a,  _Tp __val,
+                        memory_order __order) {
+  __atomic_store(&__a->__a_value, &__val,
+                 __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_load(const volatile __cxx_atomic_base_impl<_Tp>* __a,
+                      memory_order __order) {
+  _Tp __ret;
+  __atomic_load(&__a->__a_value, &__ret,
+                __to_gcc_order(__order));
+  return __ret;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_load(const __cxx_atomic_base_impl<_Tp>* __a, memory_order __order) {
+  _Tp __ret;
+  __atomic_load(&__a->__a_value, &__ret,
+                __to_gcc_order(__order));
+  return __ret;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_exchange(volatile __cxx_atomic_base_impl<_Tp>* __a,
+                          _Tp __value, memory_order __order) {
+  _Tp __ret;
+  __atomic_exchange(&__a->__a_value, &__value, &__ret,
+                    __to_gcc_order(__order));
+  return __ret;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp>* __a, _Tp __value,
+                          memory_order __order) {
+  _Tp __ret;
+  __atomic_exchange(&__a->__a_value, &__value, &__ret,
+                    __to_gcc_order(__order));
+  return __ret;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_strong(
+    volatile __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value,
+    memory_order __success, memory_order __failure) {
+  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
+                                   false,
+                                   __to_gcc_order(__success),
+                                   __to_gcc_failure_order(__failure));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_strong(
+    __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success,
+    memory_order __failure) {
+  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
+                                   false,
+                                   __to_gcc_order(__success),
+                                   __to_gcc_failure_order(__failure));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_weak(
+    volatile __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value,
+    memory_order __success, memory_order __failure) {
+  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
+                                   true,
+                                   __to_gcc_order(__success),
+                                   __to_gcc_failure_order(__failure));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_weak(
+    __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success,
+    memory_order __failure) {
+  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
+                                   true,
+                                   __to_gcc_order(__success),
+                                   __to_gcc_failure_order(__failure));
+}
+
+template <typename _Tp>
+struct __skip_amt { enum {value = 1}; };
+
+template <typename _Tp>
+struct __skip_amt<_Tp*> { enum {value = sizeof(_Tp)}; };
+
+// FIXME: Haven't figured out what the spec says about using arrays with
+// atomic_fetch_add. Force a failure rather than creating bad behavior.
+template <typename _Tp>
+struct __skip_amt<_Tp[]> { };
+template <typename _Tp, int n>
+struct __skip_amt<_Tp[n]> { };
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_add(volatile __cxx_atomic_base_impl<_Tp>* __a,
+                           _Td __delta, memory_order __order) {
+  return __atomic_fetch_add(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp>* __a, _Td __delta,
+                           memory_order __order) {
+  return __atomic_fetch_add(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_sub(volatile __cxx_atomic_base_impl<_Tp>* __a,
+                           _Td __delta, memory_order __order) {
+  return __atomic_fetch_sub(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp>* __a, _Td __delta,
+                           memory_order __order) {
+  return __atomic_fetch_sub(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_and(volatile __cxx_atomic_base_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order __order) {
+  return __atomic_fetch_and(&__a->__a_value, __pattern,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order __order) {
+  return __atomic_fetch_and(&__a->__a_value, __pattern,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_or(volatile __cxx_atomic_base_impl<_Tp>* __a,
+                          _Tp __pattern, memory_order __order) {
+  return __atomic_fetch_or(&__a->__a_value, __pattern,
+                           __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp>* __a, _Tp __pattern,
+                          memory_order __order) {
+  return __atomic_fetch_or(&__a->__a_value, __pattern,
+                           __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_xor(volatile __cxx_atomic_base_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order __order) {
+  return __atomic_fetch_xor(&__a->__a_value, __pattern,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp>* __a, _Tp __pattern,
+                           memory_order __order) {
+  return __atomic_fetch_xor(&__a->__a_value, __pattern,
+                            __to_gcc_order(__order));
+}
+
+#define __cxx_atomic_is_lock_free(__s) __atomic_is_lock_free(__s, 0)
+
+#elif defined(_LIBCPP_HAS_C_ATOMIC_IMP)
+
+template <typename _Tp>
+struct __cxx_atomic_base_impl {
+
+  _LIBCPP_INLINE_VISIBILITY
+#ifndef _LIBCPP_CXX03_LANG
+    __cxx_atomic_base_impl() _NOEXCEPT = default;
+#else
+    __cxx_atomic_base_impl() _NOEXCEPT : __a_value() {}
+#endif // _LIBCPP_CXX03_LANG
+  _LIBCPP_CONSTEXPR explicit __cxx_atomic_base_impl(_Tp __value) _NOEXCEPT
+    : __a_value(__value) {}
+  _LIBCPP_DISABLE_EXTENSION_WARNING _Atomic(_Tp) __a_value;
+};
+
+#define __cxx_atomic_is_lock_free(__s) __c11_atomic_is_lock_free(__s)
+
+_LIBCPP_INLINE_VISIBILITY inline
+void __cxx_atomic_thread_fence(memory_order __order) _NOEXCEPT {
+    __c11_atomic_thread_fence(static_cast<__memory_order_underlying_t>(__order));
+}
+
+_LIBCPP_INLINE_VISIBILITY inline
+void __cxx_atomic_signal_fence(memory_order __order) _NOEXCEPT {
+    __c11_atomic_signal_fence(static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __val) _NOEXCEPT {
+    __c11_atomic_init(&__a->__a_value, __val);
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp> * __a, _Tp __val) _NOEXCEPT {
+    __c11_atomic_init(&__a->__a_value, __val);
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __val, memory_order __order) _NOEXCEPT {
+    __c11_atomic_store(&__a->__a_value, __val, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp> * __a, _Tp __val, memory_order __order) _NOEXCEPT {
+    __c11_atomic_store(&__a->__a_value, __val, static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_load(__cxx_atomic_base_impl<_Tp> const volatile* __a, memory_order __order) _NOEXCEPT {
+    using __ptr_type = __remove_const_t<decltype(__a->__a_value)>*;
+    return __c11_atomic_load(const_cast<__ptr_type>(&__a->__a_value), static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_load(__cxx_atomic_base_impl<_Tp> const* __a, memory_order __order) _NOEXCEPT {
+    using __ptr_type = __remove_const_t<decltype(__a->__a_value)>*;
+    return __c11_atomic_load(const_cast<__ptr_type>(&__a->__a_value), static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __value, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_exchange(&__a->__a_value, __value, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp> * __a, _Tp __value, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_exchange(&__a->__a_value, __value, static_cast<__memory_order_underlying_t>(__order));
+}
+
+_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR memory_order __to_failure_order(memory_order __order) {
+  // Avoid switch statement to make this a constexpr.
+  return __order == memory_order_release ? memory_order_relaxed:
+         (__order == memory_order_acq_rel ? memory_order_acquire:
+             __order);
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
+    return __c11_atomic_compare_exchange_strong(&__a->__a_value, __expected, __value, static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_base_impl<_Tp> * __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
+    return __c11_atomic_compare_exchange_strong(&__a->__a_value, __expected, __value, static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
+    return __c11_atomic_compare_exchange_weak(&__a->__a_value, __expected, __value, static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_base_impl<_Tp> * __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
+    return __c11_atomic_compare_exchange_weak(&__a->__a_value, __expected, __value,  static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp> * __a, _Tp __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp* __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp* __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp*> * __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp> * __a, _Tp __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp* __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp* __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp*> * __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_and(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_and(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_or(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_or(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_xor(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_xor(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
+}
+
+#endif // _LIBCPP_HAS_GCC_ATOMIC_IMP, _LIBCPP_HAS_C_ATOMIC_IMP
+
+#ifdef _LIBCPP_ATOMIC_ONLY_USE_BUILTINS
+
+template<typename _Tp>
+struct __cxx_atomic_lock_impl {
+
+  _LIBCPP_INLINE_VISIBILITY
+  __cxx_atomic_lock_impl() _NOEXCEPT
+    : __a_value(), __a_lock(0) {}
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR explicit
+  __cxx_atomic_lock_impl(_Tp value) _NOEXCEPT
+    : __a_value(value), __a_lock(0) {}
+
+  _Tp __a_value;
+  mutable __cxx_atomic_base_impl<_LIBCPP_ATOMIC_FLAG_TYPE> __a_lock;
+
+  _LIBCPP_INLINE_VISIBILITY void __lock() const volatile {
+    while(1 == __cxx_atomic_exchange(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(true), memory_order_acquire))
+        /*spin*/;
+  }
+  _LIBCPP_INLINE_VISIBILITY void __lock() const {
+    while(1 == __cxx_atomic_exchange(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(true), memory_order_acquire))
+        /*spin*/;
+  }
+  _LIBCPP_INLINE_VISIBILITY void __unlock() const volatile {
+    __cxx_atomic_store(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(false), memory_order_release);
+  }
+  _LIBCPP_INLINE_VISIBILITY void __unlock() const {
+    __cxx_atomic_store(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(false), memory_order_release);
+  }
+  _LIBCPP_INLINE_VISIBILITY _Tp __read() const volatile {
+    __lock();
+    _Tp __old;
+    __cxx_atomic_assign_volatile(__old, __a_value);
+    __unlock();
+    return __old;
+  }
+  _LIBCPP_INLINE_VISIBILITY _Tp __read() const {
+    __lock();
+    _Tp __old = __a_value;
+    __unlock();
+    return __old;
+  }
+};
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_init(volatile __cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val) {
+  __cxx_atomic_assign_volatile(__a->__a_value, __val);
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_init(__cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val) {
+  __a->__a_value = __val;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_store(volatile __cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val, memory_order) {
+  __a->__lock();
+  __cxx_atomic_assign_volatile(__a->__a_value, __val);
+  __a->__unlock();
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_store(__cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val, memory_order) {
+  __a->__lock();
+  __a->__a_value = __val;
+  __a->__unlock();
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_load(const volatile __cxx_atomic_lock_impl<_Tp>* __a, memory_order) {
+  return __a->__read();
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_load(const __cxx_atomic_lock_impl<_Tp>* __a, memory_order) {
+  return __a->__read();
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_exchange(volatile __cxx_atomic_lock_impl<_Tp>* __a, _Tp __value, memory_order) {
+  __a->__lock();
+  _Tp __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, __value);
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_exchange(__cxx_atomic_lock_impl<_Tp>* __a, _Tp __value, memory_order) {
+  __a->__lock();
+  _Tp __old = __a->__a_value;
+  __a->__a_value = __value;
+  __a->__unlock();
+  return __old;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_strong(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                                          _Tp* __expected, _Tp __value, memory_order, memory_order) {
+  _Tp __temp;
+  __a->__lock();
+  __cxx_atomic_assign_volatile(__temp, __a->__a_value);
+  bool __ret = (_VSTD::memcmp(&__temp, __expected, sizeof(_Tp)) == 0);
+  if(__ret)
+    __cxx_atomic_assign_volatile(__a->__a_value, __value);
+  else
+    __cxx_atomic_assign_volatile(*__expected, __a->__a_value);
+  __a->__unlock();
+  return __ret;
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_lock_impl<_Tp>* __a,
+                                          _Tp* __expected, _Tp __value, memory_order, memory_order) {
+  __a->__lock();
+  bool __ret = (_VSTD::memcmp(&__a->__a_value, __expected, sizeof(_Tp)) == 0);
+  if(__ret)
+    _VSTD::memcpy(&__a->__a_value, &__value, sizeof(_Tp));
+  else
+    _VSTD::memcpy(__expected, &__a->__a_value, sizeof(_Tp));
+  __a->__unlock();
+  return __ret;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_weak(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                                        _Tp* __expected, _Tp __value, memory_order, memory_order) {
+  _Tp __temp;
+  __a->__lock();
+  __cxx_atomic_assign_volatile(__temp, __a->__a_value);
+  bool __ret = (_VSTD::memcmp(&__temp, __expected, sizeof(_Tp)) == 0);
+  if(__ret)
+    __cxx_atomic_assign_volatile(__a->__a_value, __value);
+  else
+    __cxx_atomic_assign_volatile(*__expected, __a->__a_value);
+  __a->__unlock();
+  return __ret;
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_lock_impl<_Tp>* __a,
+                                        _Tp* __expected, _Tp __value, memory_order, memory_order) {
+  __a->__lock();
+  bool __ret = (_VSTD::memcmp(&__a->__a_value, __expected, sizeof(_Tp)) == 0);
+  if(__ret)
+    _VSTD::memcpy(&__a->__a_value, &__value, sizeof(_Tp));
+  else
+    _VSTD::memcpy(__expected, &__a->__a_value, sizeof(_Tp));
+  __a->__unlock();
+  return __ret;
+}
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_add(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                           _Td __delta, memory_order) {
+  __a->__lock();
+  _Tp __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old + __delta));
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_add(__cxx_atomic_lock_impl<_Tp>* __a,
+                           _Td __delta, memory_order) {
+  __a->__lock();
+  _Tp __old = __a->__a_value;
+  __a->__a_value += __delta;
+  __a->__unlock();
+  return __old;
+}
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp* __cxx_atomic_fetch_add(volatile __cxx_atomic_lock_impl<_Tp*>* __a,
+                           ptrdiff_t __delta, memory_order) {
+  __a->__lock();
+  _Tp* __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, __old + __delta);
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp* __cxx_atomic_fetch_add(__cxx_atomic_lock_impl<_Tp*>* __a,
+                           ptrdiff_t __delta, memory_order) {
+  __a->__lock();
+  _Tp* __old = __a->__a_value;
+  __a->__a_value += __delta;
+  __a->__unlock();
+  return __old;
+}
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_sub(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                           _Td __delta, memory_order) {
+  __a->__lock();
+  _Tp __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old - __delta));
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_sub(__cxx_atomic_lock_impl<_Tp>* __a,
+                           _Td __delta, memory_order) {
+  __a->__lock();
+  _Tp __old = __a->__a_value;
+  __a->__a_value -= __delta;
+  __a->__unlock();
+  return __old;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_and(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order) {
+  __a->__lock();
+  _Tp __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old & __pattern));
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_and(__cxx_atomic_lock_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order) {
+  __a->__lock();
+  _Tp __old = __a->__a_value;
+  __a->__a_value &= __pattern;
+  __a->__unlock();
+  return __old;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_or(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                          _Tp __pattern, memory_order) {
+  __a->__lock();
+  _Tp __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old | __pattern));
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_or(__cxx_atomic_lock_impl<_Tp>* __a,
+                          _Tp __pattern, memory_order) {
+  __a->__lock();
+  _Tp __old = __a->__a_value;
+  __a->__a_value |= __pattern;
+  __a->__unlock();
+  return __old;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_xor(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order) {
+  __a->__lock();
+  _Tp __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old ^ __pattern));
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_xor(__cxx_atomic_lock_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order) {
+  __a->__lock();
+  _Tp __old = __a->__a_value;
+  __a->__a_value ^= __pattern;
+  __a->__unlock();
+  return __old;
+}
+
+template <typename _Tp,
+          typename _Base = typename conditional<__libcpp_is_always_lock_free<_Tp>::__value,
+                                                __cxx_atomic_base_impl<_Tp>,
+                                                __cxx_atomic_lock_impl<_Tp> >::type>
+#else
+template <typename _Tp,
+          typename _Base = __cxx_atomic_base_impl<_Tp> >
+#endif //_LIBCPP_ATOMIC_ONLY_USE_BUILTINS
+struct __cxx_atomic_impl : public _Base {
+    static_assert(is_trivially_copyable<_Tp>::value,
+      "std::atomic<T> requires that 'T' be a trivially copyable type");
+
+  _LIBCPP_INLINE_VISIBILITY __cxx_atomic_impl() _NOEXCEPT = default;
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR explicit __cxx_atomic_impl(_Tp __value) _NOEXCEPT
+    : _Base(__value) {}
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ATOMIC_CXX_ATOMIC_IMPL_H

libcxx/include/__atomic/fence.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_FENCE_H
+#define _LIBCPP___ATOMIC_FENCE_H
+
+#include <__atomic/cxx_atomic_impl.h>
+#include <__atomic/memory_order.h>
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+atomic_thread_fence(memory_order __m) _NOEXCEPT
+{
+    __cxx_atomic_thread_fence(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+atomic_signal_fence(memory_order __m) _NOEXCEPT
+{
+    __cxx_atomic_signal_fence(__m);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ATOMIC_FENCE_H

libcxx/include/__atomic/is_always_lock_free.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_IS_ALWAYS_LOCK_FREE_H
+#define _LIBCPP___ATOMIC_IS_ALWAYS_LOCK_FREE_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+struct __libcpp_is_always_lock_free {
+  // __atomic_always_lock_free is available in all Standard modes
+  static const bool __value = __atomic_always_lock_free(sizeof(_Tp), 0);
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ATOMIC_IS_ALWAYS_LOCK_FREE_H

libcxx/include/__atomic/kill_dependency.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_KILL_DEPENDENCY_H
+#define _LIBCPP___ATOMIC_KILL_DEPENDENCY_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp kill_dependency(_Tp __y) _NOEXCEPT
+{
+    return __y;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ATOMIC_KILL_DEPENDENCY_H

libcxx/include/__atomic/memory_order.h

+//===----------------------------------------------------------------------===//
+//
+// 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___ATOMIC_MEMORY_ORDER_H
+#define _LIBCPP___ATOMIC_MEMORY_ORDER_H
+
+#include <__config>
+#include <__type_traits/is_same.h>
+#include <__type_traits/underlying_type.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Figure out what the underlying type for `memory_order` would be if it were
+// declared as an unscoped enum (accounting for -fshort-enums). Use this result
+// to pin the underlying type in C++20.
+enum __legacy_memory_order {
+    __mo_relaxed,
+    __mo_consume,
+    __mo_acquire,
+    __mo_release,
+    __mo_acq_rel,
+    __mo_seq_cst
+};
+
+typedef underlying_type<__legacy_memory_order>::type __memory_order_underlying_t;
+
+#if _LIBCPP_STD_VER > 17
+
+enum class memory_order : __memory_order_underlying_t {
+  relaxed = __mo_relaxed,
+  consume = __mo_consume,
+  acquire = __mo_acquire,
+  release = __mo_release,
+  acq_rel = __mo_acq_rel,
+  seq_cst = __mo_seq_cst
+};
+
+static_assert((is_same<underlying_type<memory_order>::type, __memory_order_underlying_t>::value),
+  "unexpected underlying type for std::memory_order");
+
+inline constexpr auto memory_order_relaxed = memory_order::relaxed;
+inline constexpr auto memory_order_consume = memory_order::consume;
+inline constexpr auto memory_order_acquire = memory_order::acquire;
+inline constexpr auto memory_order_release = memory_order::release;
+inline constexpr auto memory_order_acq_rel = memory_order::acq_rel;
+inline constexpr auto memory_order_seq_cst = memory_order::seq_cst;
+
+#else
+
+typedef enum memory_order {
+  memory_order_relaxed = __mo_relaxed,
+  memory_order_consume = __mo_consume,
+  memory_order_acquire = __mo_acquire,
+  memory_order_release = __mo_release,
+  memory_order_acq_rel = __mo_acq_rel,
+  memory_order_seq_cst = __mo_seq_cst,
+} memory_order;
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ATOMIC_MEMORY_ORDER_H

libcxx/include/atomic

 
 #define ATOMIC_FLAG_INIT see below
 
 }  // std
 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
-#include <__availability>
-#include <__chrono/duration.h>
+#include <__atomic/aliases.h>
+#include <__atomic/atomic.h>
+#include <__atomic/atomic_base.h>
+#include <__atomic/atomic_flag.h>
+#include <__atomic/atomic_init.h>
+#include <__atomic/atomic_lock_free.h>
+#include <__atomic/atomic_sync.h>
+#include <__atomic/check_memory_order.h>
+#include <__atomic/contention_t.h>
+#include <__atomic/cxx_atomic_impl.h>
+#include <__atomic/fence.h>
+#include <__atomic/is_always_lock_free.h>
+#include <__atomic/kill_dependency.h>
+#include <__atomic/memory_order.h>
 #include <__config>
-#include <__thread/poll_with_backoff.h>
-#include <__thread/timed_backoff_policy.h>
-#include <__type_traits/conditional.h>
-#include <__type_traits/decay.h>
-#include <__type_traits/is_assignable.h>
-#include <__type_traits/is_function.h>
-#include <__type_traits/is_nothrow_default_constructible.h>
-#include <__type_traits/is_same.h>
-#include <__type_traits/is_trivially_copyable.h>
-#include <__type_traits/remove_const.h>
-#include <__type_traits/remove_pointer.h>
-#include <__type_traits/underlying_type.h>
 #include <cstddef>
 #include <cstdint>
 #include <cstring>
 #include <version>
 
 #ifndef _LIBCPP_HAS_NO_THREADS
 # include <__threading_support>
 #endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #ifdef _LIBCPP_HAS_NO_ATOMIC_HEADER
 # error <atomic> is not implemented
 #endif
 #ifdef kill_dependency
 # error <atomic> is incompatible with <stdatomic.h> before C++23. Please compile with -std=c++23.
 #endif
 
-#define _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m) \
-  _LIBCPP_DIAGNOSE_WARNING(__m == memory_order_consume || \
-                           __m == memory_order_acquire || \
-                           __m == memory_order_acq_rel,   \
-                        "memory order argument to atomic operation is invalid")
-
-#define _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m) \
-  _LIBCPP_DIAGNOSE_WARNING(__m == memory_order_release || \
-                           __m == memory_order_acq_rel,   \
-                        "memory order argument to atomic operation is invalid")
-
-#define _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__m, __f) \
-  _LIBCPP_DIAGNOSE_WARNING(__f == memory_order_release || \
-                           __f == memory_order_acq_rel,   \
-                        "memory order argument to atomic operation is invalid")
-
-_LIBCPP_BEGIN_NAMESPACE_STD
-
-// Figure out what the underlying type for `memory_order` would be if it were
-// declared as an unscoped enum (accounting for -fshort-enums). Use this result
-// to pin the underlying type in C++20.
-enum __legacy_memory_order {
-    __mo_relaxed,
-    __mo_consume,
-    __mo_acquire,
-    __mo_release,
-    __mo_acq_rel,
-    __mo_seq_cst
-};
-
-typedef underlying_type<__legacy_memory_order>::type __memory_order_underlying_t;
-
-#if _LIBCPP_STD_VER > 17
-
-enum class memory_order : __memory_order_underlying_t {
-  relaxed = __mo_relaxed,
-  consume = __mo_consume,
-  acquire = __mo_acquire,
-  release = __mo_release,
-  acq_rel = __mo_acq_rel,
-  seq_cst = __mo_seq_cst
-};
-
-inline constexpr auto memory_order_relaxed = memory_order::relaxed;
-inline constexpr auto memory_order_consume = memory_order::consume;
-inline constexpr auto memory_order_acquire = memory_order::acquire;
-inline constexpr auto memory_order_release = memory_order::release;
-inline constexpr auto memory_order_acq_rel = memory_order::acq_rel;
-inline constexpr auto memory_order_seq_cst = memory_order::seq_cst;
-
-#else
-
-typedef enum memory_order {
-  memory_order_relaxed = __mo_relaxed,
-  memory_order_consume = __mo_consume,
-  memory_order_acquire = __mo_acquire,
-  memory_order_release = __mo_release,
-  memory_order_acq_rel = __mo_acq_rel,
-  memory_order_seq_cst = __mo_seq_cst,
-} memory_order;
-
-#endif // _LIBCPP_STD_VER > 17
-
-template <typename _Tp> _LIBCPP_INLINE_VISIBILITY
-bool __cxx_nonatomic_compare_equal(_Tp const& __lhs, _Tp const& __rhs) {
-    return _VSTD::memcmp(&__lhs, &__rhs, sizeof(_Tp)) == 0;
-}
-
-static_assert((is_same<underlying_type<memory_order>::type, __memory_order_underlying_t>::value),
-  "unexpected underlying type for std::memory_order");
-
-#if defined(_LIBCPP_HAS_GCC_ATOMIC_IMP) || \
-    defined(_LIBCPP_ATOMIC_ONLY_USE_BUILTINS)
-
-// [atomics.types.generic]p1 guarantees _Tp is trivially copyable. Because
-// the default operator= in an object is not volatile, a byte-by-byte copy
-// is required.
-template <typename _Tp, typename _Tv> _LIBCPP_INLINE_VISIBILITY
-typename enable_if<is_assignable<_Tp&, _Tv>::value>::type
-__cxx_atomic_assign_volatile(_Tp& __a_value, _Tv const& __val) {
-  __a_value = __val;
-}
-template <typename _Tp, typename _Tv> _LIBCPP_INLINE_VISIBILITY
-typename enable_if<is_assignable<_Tp&, _Tv>::value>::type
-__cxx_atomic_assign_volatile(_Tp volatile& __a_value, _Tv volatile const& __val) {
-  volatile char* __to = reinterpret_cast<volatile char*>(&__a_value);
-  volatile char* __end = __to + sizeof(_Tp);
-  volatile const char* __from = reinterpret_cast<volatile const char*>(&__val);
-  while (__to != __end)
-    *__to++ = *__from++;
-}
-
-#endif
-
-#if defined(_LIBCPP_HAS_GCC_ATOMIC_IMP)
-
-template <typename _Tp>
-struct __cxx_atomic_base_impl {
-
-  _LIBCPP_INLINE_VISIBILITY
-#ifndef _LIBCPP_CXX03_LANG
-    __cxx_atomic_base_impl() _NOEXCEPT = default;
-#else
-    __cxx_atomic_base_impl() _NOEXCEPT : __a_value() {}
-#endif // _LIBCPP_CXX03_LANG
-  _LIBCPP_CONSTEXPR explicit __cxx_atomic_base_impl(_Tp value) _NOEXCEPT
-    : __a_value(value) {}
-  _Tp __a_value;
-};
-
-_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR int __to_gcc_order(memory_order __order) {
-  // Avoid switch statement to make this a constexpr.
-  return __order == memory_order_relaxed ? __ATOMIC_RELAXED:
-         (__order == memory_order_acquire ? __ATOMIC_ACQUIRE:
-          (__order == memory_order_release ? __ATOMIC_RELEASE:
-           (__order == memory_order_seq_cst ? __ATOMIC_SEQ_CST:
-            (__order == memory_order_acq_rel ? __ATOMIC_ACQ_REL:
-              __ATOMIC_CONSUME))));
-}
-
-_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR int __to_gcc_failure_order(memory_order __order) {
-  // Avoid switch statement to make this a constexpr.
-  return __order == memory_order_relaxed ? __ATOMIC_RELAXED:
-         (__order == memory_order_acquire ? __ATOMIC_ACQUIRE:
-          (__order == memory_order_release ? __ATOMIC_RELAXED:
-           (__order == memory_order_seq_cst ? __ATOMIC_SEQ_CST:
-            (__order == memory_order_acq_rel ? __ATOMIC_ACQUIRE:
-              __ATOMIC_CONSUME))));
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void __cxx_atomic_init(volatile __cxx_atomic_base_impl<_Tp>* __a,  _Tp __val) {
-  __cxx_atomic_assign_volatile(__a->__a_value, __val);
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp>* __a,  _Tp __val) {
-  __a->__a_value = __val;
-}
-
-_LIBCPP_INLINE_VISIBILITY inline
-void __cxx_atomic_thread_fence(memory_order __order) {
-  __atomic_thread_fence(__to_gcc_order(__order));
-}
-
-_LIBCPP_INLINE_VISIBILITY inline
-void __cxx_atomic_signal_fence(memory_order __order) {
-  __atomic_signal_fence(__to_gcc_order(__order));
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void __cxx_atomic_store(volatile __cxx_atomic_base_impl<_Tp>* __a,  _Tp __val,
-                        memory_order __order) {
-  __atomic_store(&__a->__a_value, &__val,
-                 __to_gcc_order(__order));
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp>* __a,  _Tp __val,
-                        memory_order __order) {
-  __atomic_store(&__a->__a_value, &__val,
-                 __to_gcc_order(__order));
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_load(const volatile __cxx_atomic_base_impl<_Tp>* __a,
-                      memory_order __order) {
-  _Tp __ret;
-  __atomic_load(&__a->__a_value, &__ret,
-                __to_gcc_order(__order));
-  return __ret;
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_load(const __cxx_atomic_base_impl<_Tp>* __a, memory_order __order) {
-  _Tp __ret;
-  __atomic_load(&__a->__a_value, &__ret,
-                __to_gcc_order(__order));
-  return __ret;
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_exchange(volatile __cxx_atomic_base_impl<_Tp>* __a,
-                          _Tp __value, memory_order __order) {
-  _Tp __ret;
-  __atomic_exchange(&__a->__a_value, &__value, &__ret,
-                    __to_gcc_order(__order));
-  return __ret;
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp>* __a, _Tp __value,
-                          memory_order __order) {
-  _Tp __ret;
-  __atomic_exchange(&__a->__a_value, &__value, &__ret,
-                    __to_gcc_order(__order));
-  return __ret;
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool __cxx_atomic_compare_exchange_strong(
-    volatile __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value,
-    memory_order __success, memory_order __failure) {
-  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
-                                   false,
-                                   __to_gcc_order(__success),
-                                   __to_gcc_failure_order(__failure));
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool __cxx_atomic_compare_exchange_strong(
-    __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success,
-    memory_order __failure) {
-  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
-                                   false,
-                                   __to_gcc_order(__success),
-                                   __to_gcc_failure_order(__failure));
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool __cxx_atomic_compare_exchange_weak(
-    volatile __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value,
-    memory_order __success, memory_order __failure) {
-  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
-                                   true,
-                                   __to_gcc_order(__success),
-                                   __to_gcc_failure_order(__failure));
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool __cxx_atomic_compare_exchange_weak(
-    __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success,
-    memory_order __failure) {
-  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
-                                   true,
-                                   __to_gcc_order(__success),
-                                   __to_gcc_failure_order(__failure));
-}
-
-template <typename _Tp>
-struct __skip_amt { enum {value = 1}; };
-
-template <typename _Tp>
-struct __skip_amt<_Tp*> { enum {value = sizeof(_Tp)}; };
-
-// FIXME: Haven't figured out what the spec says about using arrays with
-// atomic_fetch_add. Force a failure rather than creating bad behavior.
-template <typename _Tp>
-struct __skip_amt<_Tp[]> { };
-template <typename _Tp, int n>
-struct __skip_amt<_Tp[n]> { };
-
-template <typename _Tp, typename _Td>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_add(volatile __cxx_atomic_base_impl<_Tp>* __a,
-                           _Td __delta, memory_order __order) {
-  return __atomic_fetch_add(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
-                            __to_gcc_order(__order));
-}
-
-template <typename _Tp, typename _Td>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp>* __a, _Td __delta,
-                           memory_order __order) {
-  return __atomic_fetch_add(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
-                            __to_gcc_order(__order));
-}
-
-template <typename _Tp, typename _Td>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_sub(volatile __cxx_atomic_base_impl<_Tp>* __a,
-                           _Td __delta, memory_order __order) {
-  return __atomic_fetch_sub(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
-                            __to_gcc_order(__order));
-}
-
-template <typename _Tp, typename _Td>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp>* __a, _Td __delta,
-                           memory_order __order) {
-  return __atomic_fetch_sub(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
-                            __to_gcc_order(__order));
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_and(volatile __cxx_atomic_base_impl<_Tp>* __a,
-                           _Tp __pattern, memory_order __order) {
-  return __atomic_fetch_and(&__a->__a_value, __pattern,
-                            __to_gcc_order(__order));
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp>* __a,
-                           _Tp __pattern, memory_order __order) {
-  return __atomic_fetch_and(&__a->__a_value, __pattern,
-                            __to_gcc_order(__order));
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_or(volatile __cxx_atomic_base_impl<_Tp>* __a,
-                          _Tp __pattern, memory_order __order) {
-  return __atomic_fetch_or(&__a->__a_value, __pattern,
-                           __to_gcc_order(__order));
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp>* __a, _Tp __pattern,
-                          memory_order __order) {
-  return __atomic_fetch_or(&__a->__a_value, __pattern,
-                           __to_gcc_order(__order));
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_xor(volatile __cxx_atomic_base_impl<_Tp>* __a,
-                           _Tp __pattern, memory_order __order) {
-  return __atomic_fetch_xor(&__a->__a_value, __pattern,
-                            __to_gcc_order(__order));
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp>* __a, _Tp __pattern,
-                           memory_order __order) {
-  return __atomic_fetch_xor(&__a->__a_value, __pattern,
-                            __to_gcc_order(__order));
-}
-
-#define __cxx_atomic_is_lock_free(__s) __atomic_is_lock_free(__s, 0)
-
-#elif defined(_LIBCPP_HAS_C_ATOMIC_IMP)
-
-template <typename _Tp>
-struct __cxx_atomic_base_impl {
-
-  _LIBCPP_INLINE_VISIBILITY
-#ifndef _LIBCPP_CXX03_LANG
-    __cxx_atomic_base_impl() _NOEXCEPT = default;
-#else
-    __cxx_atomic_base_impl() _NOEXCEPT : __a_value() {}
-#endif // _LIBCPP_CXX03_LANG
-  _LIBCPP_CONSTEXPR explicit __cxx_atomic_base_impl(_Tp __value) _NOEXCEPT
-    : __a_value(__value) {}
-  _LIBCPP_DISABLE_EXTENSION_WARNING _Atomic(_Tp) __a_value;
-};
-
-#define __cxx_atomic_is_lock_free(__s) __c11_atomic_is_lock_free(__s)
-
-_LIBCPP_INLINE_VISIBILITY inline
-void __cxx_atomic_thread_fence(memory_order __order) _NOEXCEPT {
-    __c11_atomic_thread_fence(static_cast<__memory_order_underlying_t>(__order));
-}
-
-_LIBCPP_INLINE_VISIBILITY inline
-void __cxx_atomic_signal_fence(memory_order __order) _NOEXCEPT {
-    __c11_atomic_signal_fence(static_cast<__memory_order_underlying_t>(__order));
-}
-
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __val) _NOEXCEPT {
-    __c11_atomic_init(&__a->__a_value, __val);
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp> * __a, _Tp __val) _NOEXCEPT {
-    __c11_atomic_init(&__a->__a_value, __val);
-}
-
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __val, memory_order __order) _NOEXCEPT {
-    __c11_atomic_store(&__a->__a_value, __val, static_cast<__memory_order_underlying_t>(__order));
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp> * __a, _Tp __val, memory_order __order) _NOEXCEPT {
-    __c11_atomic_store(&__a->__a_value, __val, static_cast<__memory_order_underlying_t>(__order));
-}
-
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_load(__cxx_atomic_base_impl<_Tp> const volatile* __a, memory_order __order) _NOEXCEPT {
-    using __ptr_type = __remove_const_t<decltype(__a->__a_value)>*;
-    return __c11_atomic_load(const_cast<__ptr_type>(&__a->__a_value), static_cast<__memory_order_underlying_t>(__order));
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_load(__cxx_atomic_base_impl<_Tp> const* __a, memory_order __order) _NOEXCEPT {
-    using __ptr_type = __remove_const_t<decltype(__a->__a_value)>*;
-    return __c11_atomic_load(const_cast<__ptr_type>(&__a->__a_value), static_cast<__memory_order_underlying_t>(__order));
-}
-
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __value, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_exchange(&__a->__a_value, __value, static_cast<__memory_order_underlying_t>(__order));
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp> * __a, _Tp __value, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_exchange(&__a->__a_value, __value, static_cast<__memory_order_underlying_t>(__order));
-}
-
-_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR memory_order __to_failure_order(memory_order __order) {
-  // Avoid switch statement to make this a constexpr.
-  return __order == memory_order_release ? memory_order_relaxed:
-         (__order == memory_order_acq_rel ? memory_order_acquire:
-             __order);
-}
-
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
-    return __c11_atomic_compare_exchange_strong(&__a->__a_value, __expected, __value, static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_base_impl<_Tp> * __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
-    return __c11_atomic_compare_exchange_strong(&__a->__a_value, __expected, __value, static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
-}
-
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
-    return __c11_atomic_compare_exchange_weak(&__a->__a_value, __expected, __value, static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_base_impl<_Tp> * __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
-    return __c11_atomic_compare_exchange_weak(&__a->__a_value, __expected, __value,  static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
-}
-
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __delta, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp> * __a, _Tp __delta, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
-}
-
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp* __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp* __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp*> * __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
-}
-
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __delta, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp> * __a, _Tp __delta, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp* __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp* __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp*> * __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
-}
-
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_and(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_and(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
-}
-
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_or(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_or(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
-}
-
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_xor(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
-}
-template<class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
-    return __c11_atomic_fetch_xor(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
-}
-
-#endif // _LIBCPP_HAS_GCC_ATOMIC_IMP, _LIBCPP_HAS_C_ATOMIC_IMP
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp kill_dependency(_Tp __y) _NOEXCEPT
-{
-    return __y;
-}
-
-#if defined(__CLANG_ATOMIC_BOOL_LOCK_FREE)
-# define ATOMIC_BOOL_LOCK_FREE      __CLANG_ATOMIC_BOOL_LOCK_FREE
-# define ATOMIC_CHAR_LOCK_FREE      __CLANG_ATOMIC_CHAR_LOCK_FREE
-#ifndef _LIBCPP_HAS_NO_CHAR8_T
-# define ATOMIC_CHAR8_T_LOCK_FREE   __CLANG_ATOMIC_CHAR8_T_LOCK_FREE
-#endif
-# define ATOMIC_CHAR16_T_LOCK_FREE  __CLANG_ATOMIC_CHAR16_T_LOCK_FREE
-# define ATOMIC_CHAR32_T_LOCK_FREE  __CLANG_ATOMIC_CHAR32_T_LOCK_FREE
-# define ATOMIC_WCHAR_T_LOCK_FREE   __CLANG_ATOMIC_WCHAR_T_LOCK_FREE
-# define ATOMIC_SHORT_LOCK_FREE     __CLANG_ATOMIC_SHORT_LOCK_FREE
-# define ATOMIC_INT_LOCK_FREE       __CLANG_ATOMIC_INT_LOCK_FREE
-# define ATOMIC_LONG_LOCK_FREE      __CLANG_ATOMIC_LONG_LOCK_FREE
-# define ATOMIC_LLONG_LOCK_FREE     __CLANG_ATOMIC_LLONG_LOCK_FREE
-# define ATOMIC_POINTER_LOCK_FREE   __CLANG_ATOMIC_POINTER_LOCK_FREE
-#elif defined(__GCC_ATOMIC_BOOL_LOCK_FREE)
-# define ATOMIC_BOOL_LOCK_FREE      __GCC_ATOMIC_BOOL_LOCK_FREE
-# define ATOMIC_CHAR_LOCK_FREE      __GCC_ATOMIC_CHAR_LOCK_FREE
-#ifndef _LIBCPP_HAS_NO_CHAR8_T
-# define ATOMIC_CHAR8_T_LOCK_FREE   __GCC_ATOMIC_CHAR8_T_LOCK_FREE
-#endif
-# define ATOMIC_CHAR16_T_LOCK_FREE  __GCC_ATOMIC_CHAR16_T_LOCK_FREE
-# define ATOMIC_CHAR32_T_LOCK_FREE  __GCC_ATOMIC_CHAR32_T_LOCK_FREE
-# define ATOMIC_WCHAR_T_LOCK_FREE   __GCC_ATOMIC_WCHAR_T_LOCK_FREE
-# define ATOMIC_SHORT_LOCK_FREE     __GCC_ATOMIC_SHORT_LOCK_FREE
-# define ATOMIC_INT_LOCK_FREE       __GCC_ATOMIC_INT_LOCK_FREE
-# define ATOMIC_LONG_LOCK_FREE      __GCC_ATOMIC_LONG_LOCK_FREE
-# define ATOMIC_LLONG_LOCK_FREE     __GCC_ATOMIC_LLONG_LOCK_FREE
-# define ATOMIC_POINTER_LOCK_FREE   __GCC_ATOMIC_POINTER_LOCK_FREE
-#endif
-
-template <class _Tp>
-struct __libcpp_is_always_lock_free {
-  // __atomic_always_lock_free is available in all Standard modes
-  static const bool __value = __atomic_always_lock_free(sizeof(_Tp), 0);
-};
-
-#ifdef _LIBCPP_ATOMIC_ONLY_USE_BUILTINS
-
-template<typename _Tp>
-struct __cxx_atomic_lock_impl {
-
-  _LIBCPP_INLINE_VISIBILITY
-  __cxx_atomic_lock_impl() _NOEXCEPT
-    : __a_value(), __a_lock(0) {}
-  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR explicit
-  __cxx_atomic_lock_impl(_Tp value) _NOEXCEPT
-    : __a_value(value), __a_lock(0) {}
-
-  _Tp __a_value;
-  mutable __cxx_atomic_base_impl<_LIBCPP_ATOMIC_FLAG_TYPE> __a_lock;
-
-  _LIBCPP_INLINE_VISIBILITY void __lock() const volatile {
-    while(1 == __cxx_atomic_exchange(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(true), memory_order_acquire))
-        /*spin*/;
-  }
-  _LIBCPP_INLINE_VISIBILITY void __lock() const {
-    while(1 == __cxx_atomic_exchange(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(true), memory_order_acquire))
-        /*spin*/;
-  }
-  _LIBCPP_INLINE_VISIBILITY void __unlock() const volatile {
-    __cxx_atomic_store(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(false), memory_order_release);
-  }
-  _LIBCPP_INLINE_VISIBILITY void __unlock() const {
-    __cxx_atomic_store(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(false), memory_order_release);
-  }
-  _LIBCPP_INLINE_VISIBILITY _Tp __read() const volatile {
-    __lock();
-    _Tp __old;
-    __cxx_atomic_assign_volatile(__old, __a_value);
-    __unlock();
-    return __old;
-  }
-  _LIBCPP_INLINE_VISIBILITY _Tp __read() const {
-    __lock();
-    _Tp __old = __a_value;
-    __unlock();
-    return __old;
-  }
-};
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void __cxx_atomic_init(volatile __cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val) {
-  __cxx_atomic_assign_volatile(__a->__a_value, __val);
-}
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void __cxx_atomic_init(__cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val) {
-  __a->__a_value = __val;
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void __cxx_atomic_store(volatile __cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val, memory_order) {
-  __a->__lock();
-  __cxx_atomic_assign_volatile(__a->__a_value, __val);
-  __a->__unlock();
-}
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void __cxx_atomic_store(__cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val, memory_order) {
-  __a->__lock();
-  __a->__a_value = __val;
-  __a->__unlock();
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_load(const volatile __cxx_atomic_lock_impl<_Tp>* __a, memory_order) {
-  return __a->__read();
-}
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_load(const __cxx_atomic_lock_impl<_Tp>* __a, memory_order) {
-  return __a->__read();
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_exchange(volatile __cxx_atomic_lock_impl<_Tp>* __a, _Tp __value, memory_order) {
-  __a->__lock();
-  _Tp __old;
-  __cxx_atomic_assign_volatile(__old, __a->__a_value);
-  __cxx_atomic_assign_volatile(__a->__a_value, __value);
-  __a->__unlock();
-  return __old;
-}
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_exchange(__cxx_atomic_lock_impl<_Tp>* __a, _Tp __value, memory_order) {
-  __a->__lock();
-  _Tp __old = __a->__a_value;
-  __a->__a_value = __value;
-  __a->__unlock();
-  return __old;
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool __cxx_atomic_compare_exchange_strong(volatile __cxx_atomic_lock_impl<_Tp>* __a,
-                                          _Tp* __expected, _Tp __value, memory_order, memory_order) {
-  _Tp __temp;
-  __a->__lock();
-  __cxx_atomic_assign_volatile(__temp, __a->__a_value);
-  bool __ret = (_VSTD::memcmp(&__temp, __expected, sizeof(_Tp)) == 0);
-  if(__ret)
-    __cxx_atomic_assign_volatile(__a->__a_value, __value);
-  else
-    __cxx_atomic_assign_volatile(*__expected, __a->__a_value);
-  __a->__unlock();
-  return __ret;
-}
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_lock_impl<_Tp>* __a,
-                                          _Tp* __expected, _Tp __value, memory_order, memory_order) {
-  __a->__lock();
-  bool __ret = (_VSTD::memcmp(&__a->__a_value, __expected, sizeof(_Tp)) == 0);
-  if(__ret)
-    _VSTD::memcpy(&__a->__a_value, &__value, sizeof(_Tp));
-  else
-    _VSTD::memcpy(__expected, &__a->__a_value, sizeof(_Tp));
-  __a->__unlock();
-  return __ret;
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool __cxx_atomic_compare_exchange_weak(volatile __cxx_atomic_lock_impl<_Tp>* __a,
-                                        _Tp* __expected, _Tp __value, memory_order, memory_order) {
-  _Tp __temp;
-  __a->__lock();
-  __cxx_atomic_assign_volatile(__temp, __a->__a_value);
-  bool __ret = (_VSTD::memcmp(&__temp, __expected, sizeof(_Tp)) == 0);
-  if(__ret)
-    __cxx_atomic_assign_volatile(__a->__a_value, __value);
-  else
-    __cxx_atomic_assign_volatile(*__expected, __a->__a_value);
-  __a->__unlock();
-  return __ret;
-}
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_lock_impl<_Tp>* __a,
-                                        _Tp* __expected, _Tp __value, memory_order, memory_order) {
-  __a->__lock();
-  bool __ret = (_VSTD::memcmp(&__a->__a_value, __expected, sizeof(_Tp)) == 0);
-  if(__ret)
-    _VSTD::memcpy(&__a->__a_value, &__value, sizeof(_Tp));
-  else
-    _VSTD::memcpy(__expected, &__a->__a_value, sizeof(_Tp));
-  __a->__unlock();
-  return __ret;
-}
-
-template <typename _Tp, typename _Td>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_add(volatile __cxx_atomic_lock_impl<_Tp>* __a,
-                           _Td __delta, memory_order) {
-  __a->__lock();
-  _Tp __old;
-  __cxx_atomic_assign_volatile(__old, __a->__a_value);
-  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old + __delta));
-  __a->__unlock();
-  return __old;
-}
-template <typename _Tp, typename _Td>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_add(__cxx_atomic_lock_impl<_Tp>* __a,
-                           _Td __delta, memory_order) {
-  __a->__lock();
-  _Tp __old = __a->__a_value;
-  __a->__a_value += __delta;
-  __a->__unlock();
-  return __old;
-}
-
-template <typename _Tp, typename _Td>
-_LIBCPP_INLINE_VISIBILITY
-_Tp* __cxx_atomic_fetch_add(volatile __cxx_atomic_lock_impl<_Tp*>* __a,
-                           ptrdiff_t __delta, memory_order) {
-  __a->__lock();
-  _Tp* __old;
-  __cxx_atomic_assign_volatile(__old, __a->__a_value);
-  __cxx_atomic_assign_volatile(__a->__a_value, __old + __delta);
-  __a->__unlock();
-  return __old;
-}
-template <typename _Tp, typename _Td>
-_LIBCPP_INLINE_VISIBILITY
-_Tp* __cxx_atomic_fetch_add(__cxx_atomic_lock_impl<_Tp*>* __a,
-                           ptrdiff_t __delta, memory_order) {
-  __a->__lock();
-  _Tp* __old = __a->__a_value;
-  __a->__a_value += __delta;
-  __a->__unlock();
-  return __old;
-}
-
-template <typename _Tp, typename _Td>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_sub(volatile __cxx_atomic_lock_impl<_Tp>* __a,
-                           _Td __delta, memory_order) {
-  __a->__lock();
-  _Tp __old;
-  __cxx_atomic_assign_volatile(__old, __a->__a_value);
-  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old - __delta));
-  __a->__unlock();
-  return __old;
-}
-template <typename _Tp, typename _Td>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_sub(__cxx_atomic_lock_impl<_Tp>* __a,
-                           _Td __delta, memory_order) {
-  __a->__lock();
-  _Tp __old = __a->__a_value;
-  __a->__a_value -= __delta;
-  __a->__unlock();
-  return __old;
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_and(volatile __cxx_atomic_lock_impl<_Tp>* __a,
-                           _Tp __pattern, memory_order) {
-  __a->__lock();
-  _Tp __old;
-  __cxx_atomic_assign_volatile(__old, __a->__a_value);
-  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old & __pattern));
-  __a->__unlock();
-  return __old;
-}
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_and(__cxx_atomic_lock_impl<_Tp>* __a,
-                           _Tp __pattern, memory_order) {
-  __a->__lock();
-  _Tp __old = __a->__a_value;
-  __a->__a_value &= __pattern;
-  __a->__unlock();
-  return __old;
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_or(volatile __cxx_atomic_lock_impl<_Tp>* __a,
-                          _Tp __pattern, memory_order) {
-  __a->__lock();
-  _Tp __old;
-  __cxx_atomic_assign_volatile(__old, __a->__a_value);
-  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old | __pattern));
-  __a->__unlock();
-  return __old;
-}
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_or(__cxx_atomic_lock_impl<_Tp>* __a,
-                          _Tp __pattern, memory_order) {
-  __a->__lock();
-  _Tp __old = __a->__a_value;
-  __a->__a_value |= __pattern;
-  __a->__unlock();
-  return __old;
-}
-
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_xor(volatile __cxx_atomic_lock_impl<_Tp>* __a,
-                           _Tp __pattern, memory_order) {
-  __a->__lock();
-  _Tp __old;
-  __cxx_atomic_assign_volatile(__old, __a->__a_value);
-  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old ^ __pattern));
-  __a->__unlock();
-  return __old;
-}
-template <typename _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp __cxx_atomic_fetch_xor(__cxx_atomic_lock_impl<_Tp>* __a,
-                           _Tp __pattern, memory_order) {
-  __a->__lock();
-  _Tp __old = __a->__a_value;
-  __a->__a_value ^= __pattern;
-  __a->__unlock();
-  return __old;
-}
-
-template <typename _Tp,
-          typename _Base = typename conditional<__libcpp_is_always_lock_free<_Tp>::__value,
-                                                __cxx_atomic_base_impl<_Tp>,
-                                                __cxx_atomic_lock_impl<_Tp> >::type>
-#else
-template <typename _Tp,
-          typename _Base = __cxx_atomic_base_impl<_Tp> >
-#endif //_LIBCPP_ATOMIC_ONLY_USE_BUILTINS
-struct __cxx_atomic_impl : public _Base {
-    static_assert(is_trivially_copyable<_Tp>::value,
-      "std::atomic<T> requires that 'T' be a trivially copyable type");
-
-  _LIBCPP_INLINE_VISIBILITY __cxx_atomic_impl() _NOEXCEPT = default;
-  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR explicit __cxx_atomic_impl(_Tp __value) _NOEXCEPT
-    : _Base(__value) {}
-};
-
-#if defined(__linux__) || (defined(_AIX) && !defined(__64BIT__))
-    using __cxx_contention_t = int32_t;
-#else
-    using __cxx_contention_t = int64_t;
-#endif // __linux__ || (_AIX && !__64BIT__)
-
-using __cxx_atomic_contention_t = __cxx_atomic_impl<__cxx_contention_t>;
-
-#ifndef _LIBCPP_HAS_NO_THREADS
-
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(void const volatile*);
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(void const volatile*);
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t __libcpp_atomic_monitor(void const volatile*);
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __libcpp_atomic_wait(void const volatile*, __cxx_contention_t);
-
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(__cxx_atomic_contention_t const volatile*);
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(__cxx_atomic_contention_t const volatile*);
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t __libcpp_atomic_monitor(__cxx_atomic_contention_t const volatile*);
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __libcpp_atomic_wait(__cxx_atomic_contention_t const volatile*, __cxx_contention_t);
-
-template <class _Atp, class _Fn>
-struct __libcpp_atomic_wait_backoff_impl {
-    _Atp* __a;
-    _Fn __test_fn;
-    _LIBCPP_AVAILABILITY_SYNC
-    _LIBCPP_INLINE_VISIBILITY bool operator()(chrono::nanoseconds __elapsed) const
-    {
-        if(__elapsed > chrono::microseconds(64))
-        {
-            auto const __monitor = std::__libcpp_atomic_monitor(__a);
-            if(__test_fn())
-                return true;
-            std::__libcpp_atomic_wait(__a, __monitor);
-        }
-        else if(__elapsed > chrono::microseconds(4))
-            __libcpp_thread_yield();
-        else
-            {} // poll
-        return false;
-    }
-};
-
-template <class _Atp, class _Fn>
-_LIBCPP_AVAILABILITY_SYNC
-_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp* __a, _Fn && __test_fn)
-{
-    __libcpp_atomic_wait_backoff_impl<_Atp, typename decay<_Fn>::type> __backoff_fn = {__a, __test_fn};
-    return std::__libcpp_thread_poll_with_backoff(__test_fn, __backoff_fn);
-}
-
-#else // _LIBCPP_HAS_NO_THREADS
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY void __cxx_atomic_notify_all(__cxx_atomic_impl<_Tp> const volatile*) { }
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY void __cxx_atomic_notify_one(__cxx_atomic_impl<_Tp> const volatile*) { }
-template <class _Atp, class _Fn>
-_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp*, _Fn && __test_fn)
-{
-    return __libcpp_thread_poll_with_backoff(__test_fn, __spinning_backoff_policy());
-}
-
-#endif // _LIBCPP_HAS_NO_THREADS
-
-template <class _Atp, class _Tp>
-struct __cxx_atomic_wait_test_fn_impl {
-    _Atp* __a;
-    _Tp __val;
-    memory_order __order;
-    _LIBCPP_INLINE_VISIBILITY bool operator()() const
-    {
-        return !std::__cxx_nonatomic_compare_equal(std::__cxx_atomic_load(__a, __order), __val);
-    }
-};
-
-template <class _Atp, class _Tp>
-_LIBCPP_AVAILABILITY_SYNC
-_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp* __a, _Tp const __val, memory_order __order)
-{
-    __cxx_atomic_wait_test_fn_impl<_Atp, _Tp> __test_fn = {__a, __val, __order};
-    return std::__cxx_atomic_wait(__a, __test_fn);
-}
-
-// general atomic<T>
-
-template <class _Tp, bool = is_integral<_Tp>::value && !is_same<_Tp, bool>::value>
-struct __atomic_base  // false
-{
-    mutable __cxx_atomic_impl<_Tp> __a_;
-
-#if defined(__cpp_lib_atomic_is_always_lock_free)
-  static _LIBCPP_CONSTEXPR bool is_always_lock_free = __libcpp_is_always_lock_free<__cxx_atomic_impl<_Tp> >::__value;
-#endif
-
-    _LIBCPP_INLINE_VISIBILITY
-    bool is_lock_free() const volatile _NOEXCEPT
-        {return __cxx_atomic_is_lock_free(sizeof(_Tp));}
-    _LIBCPP_INLINE_VISIBILITY
-    bool is_lock_free() const _NOEXCEPT
-        {return static_cast<__atomic_base const volatile*>(this)->is_lock_free();}
-    _LIBCPP_INLINE_VISIBILITY
-    void store(_Tp __d, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
-      _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
-        {std::__cxx_atomic_store(&__a_, __d, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    void store(_Tp __d, memory_order __m = memory_order_seq_cst) _NOEXCEPT
-      _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
-        {std::__cxx_atomic_store(&__a_, __d, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp load(memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
-      _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
-        {return std::__cxx_atomic_load(&__a_, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp load(memory_order __m = memory_order_seq_cst) const _NOEXCEPT
-      _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
-        {return std::__cxx_atomic_load(&__a_, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    operator _Tp() const volatile _NOEXCEPT {return load();}
-    _LIBCPP_INLINE_VISIBILITY
-    operator _Tp() const _NOEXCEPT          {return load();}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
-        {return std::__cxx_atomic_exchange(&__a_, __d, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst) _NOEXCEPT
-        {return std::__cxx_atomic_exchange(&__a_, __d, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    bool compare_exchange_weak(_Tp& __e, _Tp __d,
-                               memory_order __s, memory_order __f) volatile _NOEXCEPT
-      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
-        {return std::__cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
-    _LIBCPP_INLINE_VISIBILITY
-    bool compare_exchange_weak(_Tp& __e, _Tp __d,
-                               memory_order __s, memory_order __f) _NOEXCEPT
-      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
-        {return std::__cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
-    _LIBCPP_INLINE_VISIBILITY
-    bool compare_exchange_strong(_Tp& __e, _Tp __d,
-                                 memory_order __s, memory_order __f) volatile _NOEXCEPT
-      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
-        {return std::__cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
-    _LIBCPP_INLINE_VISIBILITY
-    bool compare_exchange_strong(_Tp& __e, _Tp __d,
-                                 memory_order __s, memory_order __f) _NOEXCEPT
-      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
-        {return std::__cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
-    _LIBCPP_INLINE_VISIBILITY
-    bool compare_exchange_weak(_Tp& __e, _Tp __d,
-                              memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
-        {return std::__cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    bool compare_exchange_weak(_Tp& __e, _Tp __d,
-                               memory_order __m = memory_order_seq_cst) _NOEXCEPT
-        {return std::__cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    bool compare_exchange_strong(_Tp& __e, _Tp __d,
-                              memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
-        {return std::__cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    bool compare_exchange_strong(_Tp& __e, _Tp __d,
-                                 memory_order __m = memory_order_seq_cst) _NOEXCEPT
-        {return std::__cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
-
-    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void wait(_Tp __v, memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
-        {std::__cxx_atomic_wait(&__a_, __v, __m);}
-    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void wait(_Tp __v, memory_order __m = memory_order_seq_cst) const _NOEXCEPT
-        {std::__cxx_atomic_wait(&__a_, __v, __m);}
-    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_one() volatile _NOEXCEPT
-        {std::__cxx_atomic_notify_one(&__a_);}
-    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_one() _NOEXCEPT
-        {std::__cxx_atomic_notify_one(&__a_);}
-    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_all() volatile _NOEXCEPT
-        {std::__cxx_atomic_notify_all(&__a_);}
-    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_all() _NOEXCEPT
-        {std::__cxx_atomic_notify_all(&__a_);}
-
-#if _LIBCPP_STD_VER > 17
-    _LIBCPP_INLINE_VISIBILITY constexpr
-    __atomic_base() noexcept(is_nothrow_default_constructible_v<_Tp>) : __a_(_Tp()) {}
-#else
-    _LIBCPP_INLINE_VISIBILITY
-    __atomic_base() _NOEXCEPT = default;
-#endif
-
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
-    __atomic_base(_Tp __d) _NOEXCEPT : __a_(__d) {}
-
-    __atomic_base(const __atomic_base&) = delete;
-};
-
-#if defined(__cpp_lib_atomic_is_always_lock_free)
-template <class _Tp, bool __b>
-_LIBCPP_CONSTEXPR bool __atomic_base<_Tp, __b>::is_always_lock_free;
-#endif
-
-// atomic<Integral>
-
-template <class _Tp>
-struct __atomic_base<_Tp, true>
-    : public __atomic_base<_Tp, false>
-{
-    typedef __atomic_base<_Tp, false> __base;
-
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
-    __atomic_base() _NOEXCEPT = default;
-
-    _LIBCPP_INLINE_VISIBILITY
-    _LIBCPP_CONSTEXPR __atomic_base(_Tp __d) _NOEXCEPT : __base(__d) {}
-
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
-        {return std::__cxx_atomic_fetch_add(&this->__a_, __op, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
-        {return std::__cxx_atomic_fetch_add(&this->__a_, __op, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
-        {return std::__cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
-        {return std::__cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
-        {return std::__cxx_atomic_fetch_and(&this->__a_, __op, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
-        {return std::__cxx_atomic_fetch_and(&this->__a_, __op, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
-        {return std::__cxx_atomic_fetch_or(&this->__a_, __op, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
-        {return std::__cxx_atomic_fetch_or(&this->__a_, __op, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
-        {return std::__cxx_atomic_fetch_xor(&this->__a_, __op, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
-        {return std::__cxx_atomic_fetch_xor(&this->__a_, __op, __m);}
-
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator++(int) volatile _NOEXCEPT      {return fetch_add(_Tp(1));}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator++(int) _NOEXCEPT               {return fetch_add(_Tp(1));}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator--(int) volatile _NOEXCEPT      {return fetch_sub(_Tp(1));}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator--(int) _NOEXCEPT               {return fetch_sub(_Tp(1));}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator++() volatile _NOEXCEPT         {return fetch_add(_Tp(1)) + _Tp(1);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator++() _NOEXCEPT                  {return fetch_add(_Tp(1)) + _Tp(1);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator--() volatile _NOEXCEPT         {return fetch_sub(_Tp(1)) - _Tp(1);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator--() _NOEXCEPT                  {return fetch_sub(_Tp(1)) - _Tp(1);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator+=(_Tp __op) volatile _NOEXCEPT {return fetch_add(__op) + __op;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator+=(_Tp __op) _NOEXCEPT          {return fetch_add(__op) + __op;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator-=(_Tp __op) volatile _NOEXCEPT {return fetch_sub(__op) - __op;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator-=(_Tp __op) _NOEXCEPT          {return fetch_sub(__op) - __op;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator&=(_Tp __op) volatile _NOEXCEPT {return fetch_and(__op) & __op;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator&=(_Tp __op) _NOEXCEPT          {return fetch_and(__op) & __op;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator|=(_Tp __op) volatile _NOEXCEPT {return fetch_or(__op) | __op;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator|=(_Tp __op) _NOEXCEPT          {return fetch_or(__op) | __op;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator^=(_Tp __op) volatile _NOEXCEPT {return fetch_xor(__op) ^ __op;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator^=(_Tp __op) _NOEXCEPT          {return fetch_xor(__op) ^ __op;}
-};
-
-// atomic<T>
-
-template <class _Tp>
-struct atomic
-    : public __atomic_base<_Tp>
-{
-    typedef __atomic_base<_Tp> __base;
-    typedef _Tp value_type;
-    typedef value_type difference_type;
-
-#if _LIBCPP_STD_VER > 17
-    _LIBCPP_INLINE_VISIBILITY
-    atomic() = default;
-#else
-    _LIBCPP_INLINE_VISIBILITY
-    atomic() _NOEXCEPT = default;
-#endif
-
-    _LIBCPP_INLINE_VISIBILITY
-    _LIBCPP_CONSTEXPR atomic(_Tp __d) _NOEXCEPT : __base(__d) {}
-
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator=(_Tp __d) volatile _NOEXCEPT
-        {__base::store(__d); return __d;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp operator=(_Tp __d) _NOEXCEPT
-        {__base::store(__d); return __d;}
-
-    atomic& operator=(const atomic&) = delete;
-    atomic& operator=(const atomic&) volatile = delete;
-};
-
-// atomic<T*>
-
-template <class _Tp>
-struct atomic<_Tp*>
-    : public __atomic_base<_Tp*>
-{
-    typedef __atomic_base<_Tp*> __base;
-    typedef _Tp* value_type;
-    typedef ptrdiff_t difference_type;
-
-    _LIBCPP_INLINE_VISIBILITY
-    atomic() _NOEXCEPT = default;
-
-    _LIBCPP_INLINE_VISIBILITY
-    _LIBCPP_CONSTEXPR atomic(_Tp* __d) _NOEXCEPT : __base(__d) {}
-
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator=(_Tp* __d) volatile _NOEXCEPT
-        {__base::store(__d); return __d;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator=(_Tp* __d) _NOEXCEPT
-        {__base::store(__d); return __d;}
-
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT {
-        // __atomic_fetch_add accepts function pointers, guard against them.
-        static_assert(!is_function<__remove_pointer_t<_Tp> >::value, "Pointer to function isn't allowed");
-        return std::__cxx_atomic_fetch_add(&this->__a_, __op, __m);
-    }
-
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT {
-        // __atomic_fetch_add accepts function pointers, guard against them.
-        static_assert(!is_function<__remove_pointer_t<_Tp> >::value, "Pointer to function isn't allowed");
-        return std::__cxx_atomic_fetch_add(&this->__a_, __op, __m);
-    }
-
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT {
-        // __atomic_fetch_add accepts function pointers, guard against them.
-        static_assert(!is_function<__remove_pointer_t<_Tp> >::value, "Pointer to function isn't allowed");
-        return std::__cxx_atomic_fetch_sub(&this->__a_, __op, __m);
-    }
-
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT {
-        // __atomic_fetch_add accepts function pointers, guard against them.
-        static_assert(!is_function<__remove_pointer_t<_Tp> >::value, "Pointer to function isn't allowed");
-        return std::__cxx_atomic_fetch_sub(&this->__a_, __op, __m);
-    }
-
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator++(int) volatile _NOEXCEPT            {return fetch_add(1);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator++(int) _NOEXCEPT                     {return fetch_add(1);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator--(int) volatile _NOEXCEPT            {return fetch_sub(1);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator--(int) _NOEXCEPT                     {return fetch_sub(1);}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator++() volatile _NOEXCEPT               {return fetch_add(1) + 1;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator++() _NOEXCEPT                        {return fetch_add(1) + 1;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator--() volatile _NOEXCEPT               {return fetch_sub(1) - 1;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator--() _NOEXCEPT                        {return fetch_sub(1) - 1;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator+=(ptrdiff_t __op) volatile _NOEXCEPT {return fetch_add(__op) + __op;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator+=(ptrdiff_t __op) _NOEXCEPT          {return fetch_add(__op) + __op;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator-=(ptrdiff_t __op) volatile _NOEXCEPT {return fetch_sub(__op) - __op;}
-    _LIBCPP_INLINE_VISIBILITY
-    _Tp* operator-=(ptrdiff_t __op) _NOEXCEPT          {return fetch_sub(__op) - __op;}
-
-    atomic& operator=(const atomic&) = delete;
-    atomic& operator=(const atomic&) volatile = delete;
-};
-
-// atomic_is_lock_free
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool
-atomic_is_lock_free(const volatile atomic<_Tp>* __o) _NOEXCEPT
-{
-    return __o->is_lock_free();
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool
-atomic_is_lock_free(const atomic<_Tp>* __o) _NOEXCEPT
-{
-    return __o->is_lock_free();
-}
-
-// atomic_init
-
-template <class _Tp>
-_LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_INLINE_VISIBILITY
-void
-atomic_init(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
-{
-    std::__cxx_atomic_init(&__o->__a_, __d);
-}
-
-template <class _Tp>
-_LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_INLINE_VISIBILITY
-void
-atomic_init(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
-{
-    std::__cxx_atomic_init(&__o->__a_, __d);
-}
-
-// atomic_store
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void
-atomic_store(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
-{
-    __o->store(__d);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void
-atomic_store(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
-{
-    __o->store(__d);
-}
-
-// atomic_store_explicit
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void
-atomic_store_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
-  _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
-{
-    __o->store(__d, __m);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-void
-atomic_store_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
-  _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
-{
-    __o->store(__d, __m);
-}
-
-// atomic_load
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp
-atomic_load(const volatile atomic<_Tp>* __o) _NOEXCEPT
-{
-    return __o->load();
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp
-atomic_load(const atomic<_Tp>* __o) _NOEXCEPT
-{
-    return __o->load();
-}
-
-// atomic_load_explicit
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp
-atomic_load_explicit(const volatile atomic<_Tp>* __o, memory_order __m) _NOEXCEPT
-  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
-{
-    return __o->load(__m);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp
-atomic_load_explicit(const atomic<_Tp>* __o, memory_order __m) _NOEXCEPT
-  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
-{
-    return __o->load(__m);
-}
-
-// atomic_exchange
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp
-atomic_exchange(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
-{
-    return __o->exchange(__d);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp
-atomic_exchange(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
-{
-    return __o->exchange(__d);
-}
-
-// atomic_exchange_explicit
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp
-atomic_exchange_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
-{
-    return __o->exchange(__d, __m);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp
-atomic_exchange_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
-{
-    return __o->exchange(__d, __m);
-}
-
-// atomic_compare_exchange_weak
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool
-atomic_compare_exchange_weak(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
-{
-    return __o->compare_exchange_weak(*__e, __d);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool
-atomic_compare_exchange_weak(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
-{
-    return __o->compare_exchange_weak(*__e, __d);
-}
-
-// atomic_compare_exchange_strong
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool
-atomic_compare_exchange_strong(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
-{
-    return __o->compare_exchange_strong(*__e, __d);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool
-atomic_compare_exchange_strong(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
-{
-    return __o->compare_exchange_strong(*__e, __d);
-}
-
-// atomic_compare_exchange_weak_explicit
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool
-atomic_compare_exchange_weak_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e,
-                                      typename atomic<_Tp>::value_type __d,
-                                      memory_order __s, memory_order __f) _NOEXCEPT
-  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
-{
-    return __o->compare_exchange_weak(*__e, __d, __s, __f);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool
-atomic_compare_exchange_weak_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d,
-                                      memory_order __s, memory_order __f) _NOEXCEPT
-  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
-{
-    return __o->compare_exchange_weak(*__e, __d, __s, __f);
-}
-
-// atomic_compare_exchange_strong_explicit
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool
-atomic_compare_exchange_strong_explicit(volatile atomic<_Tp>* __o,
-                                        typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d,
-                                        memory_order __s, memory_order __f) _NOEXCEPT
-  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
-{
-    return __o->compare_exchange_strong(*__e, __d, __s, __f);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-bool
-atomic_compare_exchange_strong_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e,
-                                        typename atomic<_Tp>::value_type __d,
-                                        memory_order __s, memory_order __f) _NOEXCEPT
-  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
-{
-    return __o->compare_exchange_strong(*__e, __d, __s, __f);
-}
-
-// atomic_wait
-
-template <class _Tp>
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-void atomic_wait(const volatile atomic<_Tp>* __o,
-                 typename atomic<_Tp>::value_type __v) _NOEXCEPT
-{
-    return __o->wait(__v);
-}
-
-template <class _Tp>
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-void atomic_wait(const atomic<_Tp>* __o,
-                 typename atomic<_Tp>::value_type __v) _NOEXCEPT
-{
-    return __o->wait(__v);
-}
-
-// atomic_wait_explicit
-
-template <class _Tp>
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-void atomic_wait_explicit(const volatile atomic<_Tp>* __o,
-                          typename atomic<_Tp>::value_type __v,
-                          memory_order __m) _NOEXCEPT
-  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
-{
-    return __o->wait(__v, __m);
-}
-
-template <class _Tp>
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-void atomic_wait_explicit(const atomic<_Tp>* __o,
-                          typename atomic<_Tp>::value_type __v,
-                          memory_order __m) _NOEXCEPT
-  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
-{
-    return __o->wait(__v, __m);
-}
-
-// atomic_notify_one
-
-template <class _Tp>
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-void atomic_notify_one(volatile atomic<_Tp>* __o) _NOEXCEPT
-{
-    __o->notify_one();
-}
-template <class _Tp>
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-void atomic_notify_one(atomic<_Tp>* __o) _NOEXCEPT
-{
-    __o->notify_one();
-}
-
-// atomic_notify_all
-
-template <class _Tp>
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-void atomic_notify_all(volatile atomic<_Tp>* __o) _NOEXCEPT
-{
-    __o->notify_all();
-}
-template <class _Tp>
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-void atomic_notify_all(atomic<_Tp>* __o) _NOEXCEPT
-{
-    __o->notify_all();
-}
-
-// atomic_fetch_add
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp
-atomic_fetch_add(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
-{
-    return __o->fetch_add(__op);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp
-atomic_fetch_add(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
-{
-    return __o->fetch_add(__op);
-}
-
-// atomic_fetch_add_explicit
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp atomic_fetch_add_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
-{
-    return __o->fetch_add(__op, __m);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp atomic_fetch_add_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
-{
-    return __o->fetch_add(__op, __m);
-}
-
-// atomic_fetch_sub
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp atomic_fetch_sub(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
-{
-    return __o->fetch_sub(__op);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp atomic_fetch_sub(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
-{
-    return __o->fetch_sub(__op);
-}
-
-// atomic_fetch_sub_explicit
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp atomic_fetch_sub_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
-{
-    return __o->fetch_sub(__op, __m);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-_Tp atomic_fetch_sub_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
-{
-    return __o->fetch_sub(__op, __m);
-}
-
-// atomic_fetch_and
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
-    _Tp
->::type
-atomic_fetch_and(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
-{
-    return __o->fetch_and(__op);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
-    _Tp
->::type
-atomic_fetch_and(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
-{
-    return __o->fetch_and(__op);
-}
-
-// atomic_fetch_and_explicit
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
-    _Tp
->::type
-atomic_fetch_and_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
-{
-    return __o->fetch_and(__op, __m);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
-    _Tp
->::type
-atomic_fetch_and_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
-{
-    return __o->fetch_and(__op, __m);
-}
-
-// atomic_fetch_or
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
-    _Tp
->::type
-atomic_fetch_or(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
-{
-    return __o->fetch_or(__op);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
-    _Tp
->::type
-atomic_fetch_or(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
-{
-    return __o->fetch_or(__op);
-}
-
-// atomic_fetch_or_explicit
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
-    _Tp
->::type
-atomic_fetch_or_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
-{
-    return __o->fetch_or(__op, __m);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
-    _Tp
->::type
-atomic_fetch_or_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
-{
-    return __o->fetch_or(__op, __m);
-}
-
-// atomic_fetch_xor
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
-    _Tp
->::type
-atomic_fetch_xor(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
-{
-    return __o->fetch_xor(__op);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
-    _Tp
->::type
-atomic_fetch_xor(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
-{
-    return __o->fetch_xor(__op);
-}
-
-// atomic_fetch_xor_explicit
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
-    _Tp
->::type
-atomic_fetch_xor_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
-{
-    return __o->fetch_xor(__op, __m);
-}
-
-template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
-    _Tp
->::type
-atomic_fetch_xor_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
-{
-    return __o->fetch_xor(__op, __m);
-}
-
-// flag type and operations
-
-typedef struct atomic_flag
-{
-    __cxx_atomic_impl<_LIBCPP_ATOMIC_FLAG_TYPE> __a_;
-
-    _LIBCPP_INLINE_VISIBILITY
-    bool test(memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
-        {return _LIBCPP_ATOMIC_FLAG_TYPE(true) == __cxx_atomic_load(&__a_, __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    bool test(memory_order __m = memory_order_seq_cst) const _NOEXCEPT
-        {return _LIBCPP_ATOMIC_FLAG_TYPE(true) == __cxx_atomic_load(&__a_, __m);}
-
-    _LIBCPP_INLINE_VISIBILITY
-    bool test_and_set(memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
-        {return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    bool test_and_set(memory_order __m = memory_order_seq_cst) _NOEXCEPT
-        {return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    void clear(memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
-        {__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
-    _LIBCPP_INLINE_VISIBILITY
-    void clear(memory_order __m = memory_order_seq_cst) _NOEXCEPT
-        {__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
-
-    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-    void wait(bool __v, memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
-        {__cxx_atomic_wait(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(__v), __m);}
-    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-    void wait(bool __v, memory_order __m = memory_order_seq_cst) const _NOEXCEPT
-        {__cxx_atomic_wait(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(__v), __m);}
-    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-    void notify_one() volatile _NOEXCEPT
-        {__cxx_atomic_notify_one(&__a_);}
-    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-    void notify_one() _NOEXCEPT
-        {__cxx_atomic_notify_one(&__a_);}
-    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-    void notify_all() volatile _NOEXCEPT
-        {__cxx_atomic_notify_all(&__a_);}
-    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
-    void notify_all() _NOEXCEPT
-        {__cxx_atomic_notify_all(&__a_);}
-
-#if _LIBCPP_STD_VER > 17
-    _LIBCPP_INLINE_VISIBILITY constexpr
-    atomic_flag() _NOEXCEPT : __a_(false) {}
-#else
-    _LIBCPP_INLINE_VISIBILITY
-    atomic_flag() _NOEXCEPT = default;
-#endif
-
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
-    atomic_flag(bool __b) _NOEXCEPT : __a_(__b) {} // EXTENSION
-
-    atomic_flag(const atomic_flag&) = delete;
-    atomic_flag& operator=(const atomic_flag&) = delete;
-    atomic_flag& operator=(const atomic_flag&) volatile = delete;
-
-} atomic_flag;
-
-
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-atomic_flag_test(const volatile atomic_flag* __o) _NOEXCEPT
-{
-    return __o->test();
-}
-
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-atomic_flag_test(const atomic_flag* __o) _NOEXCEPT
-{
-    return __o->test();
-}
-
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-atomic_flag_test_explicit(const volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
-{
-    return __o->test(__m);
-}
-
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-atomic_flag_test_explicit(const atomic_flag* __o, memory_order __m) _NOEXCEPT
-{
-    return __o->test(__m);
-}
-
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-atomic_flag_test_and_set(volatile atomic_flag* __o) _NOEXCEPT
-{
-    return __o->test_and_set();
-}
-
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-atomic_flag_test_and_set(atomic_flag* __o) _NOEXCEPT
-{
-    return __o->test_and_set();
-}
-
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-atomic_flag_test_and_set_explicit(volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
-{
-    return __o->test_and_set(__m);
-}
-
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-atomic_flag_test_and_set_explicit(atomic_flag* __o, memory_order __m) _NOEXCEPT
-{
-    return __o->test_and_set(__m);
-}
-
-inline _LIBCPP_INLINE_VISIBILITY
-void
-atomic_flag_clear(volatile atomic_flag* __o) _NOEXCEPT
-{
-    __o->clear();
-}
-
-inline _LIBCPP_INLINE_VISIBILITY
-void
-atomic_flag_clear(atomic_flag* __o) _NOEXCEPT
-{
-    __o->clear();
-}
-
-inline _LIBCPP_INLINE_VISIBILITY
-void
-atomic_flag_clear_explicit(volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
-{
-    __o->clear(__m);
-}
-
-inline _LIBCPP_INLINE_VISIBILITY
-void
-atomic_flag_clear_explicit(atomic_flag* __o, memory_order __m) _NOEXCEPT
-{
-    __o->clear(__m);
-}
-
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
-void
-atomic_flag_wait(const volatile atomic_flag* __o, bool __v) _NOEXCEPT
-{
-    __o->wait(__v);
-}
-
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
-void
-atomic_flag_wait(const atomic_flag* __o, bool __v) _NOEXCEPT
-{
-    __o->wait(__v);
-}
-
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
-void
-atomic_flag_wait_explicit(const volatile atomic_flag* __o,
-                          bool __v, memory_order __m) _NOEXCEPT
-{
-    __o->wait(__v, __m);
-}
-
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
-void
-atomic_flag_wait_explicit(const atomic_flag* __o,
-                          bool __v, memory_order __m) _NOEXCEPT
-{
-    __o->wait(__v, __m);
-}
-
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
-void
-atomic_flag_notify_one(volatile atomic_flag* __o) _NOEXCEPT
-{
-    __o->notify_one();
-}
-
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
-void
-atomic_flag_notify_one(atomic_flag* __o) _NOEXCEPT
-{
-    __o->notify_one();
-}
-
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
-void
-atomic_flag_notify_all(volatile atomic_flag* __o) _NOEXCEPT
-{
-    __o->notify_all();
-}
-
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
-void
-atomic_flag_notify_all(atomic_flag* __o) _NOEXCEPT
-{
-    __o->notify_all();
-}
-
-// fences
-
-inline _LIBCPP_INLINE_VISIBILITY
-void
-atomic_thread_fence(memory_order __m) _NOEXCEPT
-{
-    __cxx_atomic_thread_fence(__m);
-}
-
-inline _LIBCPP_INLINE_VISIBILITY
-void
-atomic_signal_fence(memory_order __m) _NOEXCEPT
-{
-    __cxx_atomic_signal_fence(__m);
-}
-
-// Atomics for standard typedef types
-
-typedef atomic<bool>               atomic_bool;
-typedef atomic<char>               atomic_char;
-typedef atomic<signed char>        atomic_schar;
-typedef atomic<unsigned char>      atomic_uchar;
-typedef atomic<short>              atomic_short;
-typedef atomic<unsigned short>     atomic_ushort;
-typedef atomic<int>                atomic_int;
-typedef atomic<unsigned int>       atomic_uint;
-typedef atomic<long>               atomic_long;
-typedef atomic<unsigned long>      atomic_ulong;
-typedef atomic<long long>          atomic_llong;
-typedef atomic<unsigned long long> atomic_ullong;
-#ifndef _LIBCPP_HAS_NO_CHAR8_T
-typedef atomic<char8_t>            atomic_char8_t;
-#endif
-typedef atomic<char16_t>           atomic_char16_t;
-typedef atomic<char32_t>           atomic_char32_t;
-#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
-typedef atomic<wchar_t>            atomic_wchar_t;
-#endif
-
-typedef atomic<int_least8_t>   atomic_int_least8_t;
-typedef atomic<uint_least8_t>  atomic_uint_least8_t;
-typedef atomic<int_least16_t>  atomic_int_least16_t;
-typedef atomic<uint_least16_t> atomic_uint_least16_t;
-typedef atomic<int_least32_t>  atomic_int_least32_t;
-typedef atomic<uint_least32_t> atomic_uint_least32_t;
-typedef atomic<int_least64_t>  atomic_int_least64_t;
-typedef atomic<uint_least64_t> atomic_uint_least64_t;
-
-typedef atomic<int_fast8_t>   atomic_int_fast8_t;
-typedef atomic<uint_fast8_t>  atomic_uint_fast8_t;
-typedef atomic<int_fast16_t>  atomic_int_fast16_t;
-typedef atomic<uint_fast16_t> atomic_uint_fast16_t;
-typedef atomic<int_fast32_t>  atomic_int_fast32_t;
-typedef atomic<uint_fast32_t> atomic_uint_fast32_t;
-typedef atomic<int_fast64_t>  atomic_int_fast64_t;
-typedef atomic<uint_fast64_t> atomic_uint_fast64_t;
-
-typedef atomic< int8_t>  atomic_int8_t;
-typedef atomic<uint8_t>  atomic_uint8_t;
-typedef atomic< int16_t> atomic_int16_t;
-typedef atomic<uint16_t> atomic_uint16_t;
-typedef atomic< int32_t> atomic_int32_t;
-typedef atomic<uint32_t> atomic_uint32_t;
-typedef atomic< int64_t> atomic_int64_t;
-typedef atomic<uint64_t> atomic_uint64_t;
-
-typedef atomic<intptr_t>  atomic_intptr_t;
-typedef atomic<uintptr_t> atomic_uintptr_t;
-typedef atomic<size_t>    atomic_size_t;
-typedef atomic<ptrdiff_t> atomic_ptrdiff_t;
-typedef atomic<intmax_t>  atomic_intmax_t;
-typedef atomic<uintmax_t> atomic_uintmax_t;
-
-// atomic_*_lock_free : prefer the contention type most highly, then the largest lock-free type
-
-#ifdef __cpp_lib_atomic_is_always_lock_free
-# define _LIBCPP_CONTENTION_LOCK_FREE ::std::__libcpp_is_always_lock_free<__cxx_contention_t>::__value
-#else
-# define _LIBCPP_CONTENTION_LOCK_FREE false
-#endif
-
-#if ATOMIC_LLONG_LOCK_FREE == 2
-typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, long long>          __libcpp_signed_lock_free;
-typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned long long> __libcpp_unsigned_lock_free;
-#elif ATOMIC_INT_LOCK_FREE == 2
-typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, int>                __libcpp_signed_lock_free;
-typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned int>       __libcpp_unsigned_lock_free;
-#elif ATOMIC_SHORT_LOCK_FREE == 2
-typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, short>              __libcpp_signed_lock_free;
-typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned short>     __libcpp_unsigned_lock_free;
-#elif ATOMIC_CHAR_LOCK_FREE == 2
-typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, char>               __libcpp_signed_lock_free;
-typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned char>      __libcpp_unsigned_lock_free;
-#else
-    // No signed/unsigned lock-free types
-#define _LIBCPP_NO_LOCK_FREE_TYPES
-#endif
-
-#if !defined(_LIBCPP_NO_LOCK_FREE_TYPES)
-typedef atomic<__libcpp_signed_lock_free> atomic_signed_lock_free;
-typedef atomic<__libcpp_unsigned_lock_free> atomic_unsigned_lock_free;
-#endif
-
-#define ATOMIC_FLAG_INIT {false}
-#define ATOMIC_VAR_INIT(__v) {__v}
-
-#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS)
-# if defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER >= 1400
-#  pragma clang deprecated(ATOMIC_VAR_INIT)
-# endif
-#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS)
-
-_LIBCPP_END_NAMESPACE_STD
-
 #if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
 #  include <cmath>
 #  include <compare>
 #  include <type_traits>
 #endif
 
 #endif // _LIBCPP_ATOMIC

libcxx/include/libcxx.imp

[
   { include: [ "<__std_stream>", "private", "<iostream>", "public" ] },
   { include: [ "<__threading_support>", "private", "<atomic>", "public" ] },
   { include: [ "<__threading_support>", "private", "<mutex>", "public" ] },
   { include: [ "<__threading_support>", "private", "<semaphore>", "public" ] },
   { include: [ "<__threading_support>", "private", "<thread>", "public" ] },
   { include: [ "<__tree>", "private", "<map>", "public" ] },
   { include: [ "<__tree>", "private", "<set>", "public" ] },
   { include: [ "@<__algorithm/.*>", "private", "<algorithm>", "public" ] },
+  { include: [ "@<__atomic/.*>", "private", "<atomic>", "public" ] },
   { include: [ "@<__bit/.*>", "private", "<bit>", "public" ] },
   { include: [ "@<__charconv/.*>", "private", "<charconv>", "public" ] },
   { include: [ "@<__chrono/.*>", "private", "<chrono>", "public" ] },
   { include: [ "@<__compare/.*>", "private", "<compare>", "public" ] },
   { include: [ "@<__concepts/.*>", "private", "<concepts>", "public" ] },
   { include: [ "@<__coroutine/.*>", "private", "<coroutine>", "public" ] },
   { include: [ "@<__debug_utils/.*>", "private", "<debug_utils>", "public" ] },
   { include: [ "@<__expected/.*>", "private", "<expected>", "public" ] },

libcxx/include/module.modulemap.in

module array {
     export initializer_list
     export *
 
     module array_fwd { private header "__fwd/array.h" }
   }
   module atomic {
     header "atomic"
     export *
+
+    module __atomic {
+      module aliases             { private header "__atomic/aliases.h" }
+      module atomic              { private header "__atomic/atomic.h" }
+      module atomic_base         { private header "__atomic/atomic_base.h" }
+      module atomic_flag         { private header "__atomic/atomic_flag.h" }
+      module atomic_init         { private header "__atomic/atomic_init.h" }
+      module atomic_lock_free    { private header "__atomic/atomic_lock_free.h" }
+      module atomic_sync         { private header "__atomic/atomic_sync.h" }
+      module check_memory_order  { private header "__atomic/check_memory_order.h" }
+      module contention_t        { private header "__atomic/contention_t.h" }
+      module cxx_atomic_impl     { private header "__atomic/cxx_atomic_impl.h" }
+      module fence               { private header "__atomic/fence.h" }
+      module is_always_lock_free { private header "__atomic/is_always_lock_free.h" }
+      module kill_dependency     { private header "__atomic/kill_dependency.h" }
+      module memory_order        { private header "__atomic/memory_order.h" }
+    }
   }
   module barrier {
     @requires_LIBCXX_ENABLE_THREADS@
     header "barrier"
     export *
   }
   module bit {
     header "bit"
module type_traits {
     module remove_extent                       { private header "__type_traits/remove_extent.h" }
     module remove_pointer                      { private header "__type_traits/remove_pointer.h" }
     module remove_reference                    { private header "__type_traits/remove_reference.h" }
     module remove_volatile                     { private header "__type_traits/remove_volatile.h" }
     module result_of                           { private header "__type_traits/result_of.h" }
     module strip_signature                     { private header "__type_traits/strip_signature.h" }
     module type_identity                       { private header "__type_traits/type_identity.h" }
     module type_list                           { private header "__type_traits/type_list.h" }
-    module underlying_type                     { private header "__type_traits/underlying_type.h" }
+    module underlying_type                     {
+      private header "__type_traits/underlying_type.h"
+
+      export type_traits
+    }
     module void_t                              { private header "__type_traits/void_t.h" }
   }
   module typeindex {
     header "typeindex"
     export *
   }
   module typeinfo {
     header "typeinfo"

libcxx/test/libcxx/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_add.verify.cpp

 // template <class T>
 //     T* atomic_fetch_add(atomic<T*>* obj, ptrdiff_t op);
 
 #include <atomic>
 
 void void_pointer() {
   {
     volatile std::atomic<void*> obj;
-    // expected-error@atomic:* {{incomplete type 'void' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'void' where a complete type is required}}
     std::atomic_fetch_add(&obj, 0);
   }
   {
     std::atomic<void*> obj;
-    // expected-error@atomic:* {{incomplete type 'void' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'void' where a complete type is required}}
     std::atomic_fetch_add(&obj, 0);
   }
 }
 
 struct Incomplete;
 
 void pointer_to_incomplete_type() {
   {
     volatile std::atomic<Incomplete*> obj;
-    // expected-error@atomic:* {{incomplete type 'Incomplete' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'Incomplete' where a complete type is required}}
     std::atomic_fetch_add(&obj, 0);
   }
   {
     std::atomic<Incomplete*> obj;
-    // expected-error@atomic:* {{incomplete type 'Incomplete' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'Incomplete' where a complete type is required}}
     std::atomic_fetch_add(&obj, 0);
   }
 }
 
 void function_pointer() {
   {
     volatile std::atomic<void (*)(int)> fun;
-    // expected-error-re@atomic:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
+    // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
     std::atomic_fetch_add(&fun, 0);
   }
   {
     std::atomic<void (*)(int)> fun;
-    // expected-error-re@atomic:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
+    // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
     std::atomic_fetch_add(&fun, 0);
   }
 }
 
 struct S {
   void fun(int);
 };
 
 void member_function_pointer() {
   {
     volatile std::atomic<void (S::*)(int)> fun;
-    // expected-error@atomic:* {{no member named 'fetch_add' in}}
+    // expected-error@*:* {{no member named 'fetch_add' in}}
     std::atomic_fetch_add(&fun, 0);
   }
   {
     std::atomic<void (S::*)(int)> fun;
-    // expected-error@atomic:* {{no member named 'fetch_add' in}}
+    // expected-error@*:* {{no member named 'fetch_add' in}}
     std::atomic_fetch_add(&fun, 0);
   }
 }

libcxx/test/libcxx/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_add_explicit.verify.cpp

 //     T*
 //     atomic_fetch_add_explicit(atomic<T*>* obj, ptrdiff_t op, memory_order m);
 
 #include <atomic>
 
 void void_pointer() {
   {
     volatile std::atomic<void*> obj;
-    // expected-error@atomic:* {{incomplete type 'void' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'void' where a complete type is required}}
     std::atomic_fetch_add_explicit(&obj, 0, std::memory_order_relaxed);
   }
   {
     std::atomic<void*> obj;
-    // expected-error@atomic:* {{incomplete type 'void' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'void' where a complete type is required}}
     std::atomic_fetch_add_explicit(&obj, 0, std::memory_order_relaxed);
   }
 }
 
 struct Incomplete;
 
 void pointer_to_incomplete_type() {
   {
     volatile std::atomic<Incomplete*> obj;
-    // expected-error@atomic:* {{incomplete type 'Incomplete' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'Incomplete' where a complete type is required}}
     std::atomic_fetch_add_explicit(&obj, 0, std::memory_order_relaxed);
   }
   {
     std::atomic<Incomplete*> obj;
-    // expected-error@atomic:* {{incomplete type 'Incomplete' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'Incomplete' where a complete type is required}}
     std::atomic_fetch_add_explicit(&obj, 0, std::memory_order_relaxed);
   }
 }
 
 void function_pointer() {
   {
     volatile std::atomic<void (*)(int)> fun;
-    // expected-error-re@atomic:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
+    // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
     std::atomic_fetch_add_explicit(&fun, 0, std::memory_order_relaxed);
   }
   {
     std::atomic<void (*)(int)> fun;
-    // expected-error-re@atomic:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
+    // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
     std::atomic_fetch_add_explicit(&fun, 0, std::memory_order_relaxed);
   }
 }
 
 struct S {
   void fun(int);
 };
 
 void member_function_pointer() {
   {
     volatile std::atomic<void (S::*)(int)> fun;
-    // expected-error@atomic:* {{no member named 'fetch_add' in}}
+    // expected-error@*:* {{no member named 'fetch_add' in}}
     std::atomic_fetch_add_explicit(&fun, 0, std::memory_order_relaxed);
   }
   {
     std::atomic<void (S::*)(int)> fun;
-    // expected-error@atomic:* {{no member named 'fetch_add' in}}
+    // expected-error@*:* {{no member named 'fetch_add' in}}
     std::atomic_fetch_add_explicit(&fun, 0, std::memory_order_relaxed);
   }
 }

libcxx/test/libcxx/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_sub.verify.cpp

 // template <class T>
 //     T* atomic_fetch_sub(atomic<T*>* obj, ptrdiff_t op);
 
 #include <atomic>
 
 void void_pointer() {
   {
     volatile std::atomic<void*> obj;
-    // expected-error@atomic:* {{incomplete type 'void' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'void' where a complete type is required}}
     std::atomic_fetch_sub(&obj, 0);
   }
   {
     std::atomic<void*> obj;
-    // expected-error@atomic:* {{incomplete type 'void' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'void' where a complete type is required}}
     std::atomic_fetch_sub(&obj, 0);
   }
 }
 
 struct Incomplete;
 
 void pointer_to_incomplete_type() {
   {
     volatile std::atomic<Incomplete*> obj;
-    // expected-error@atomic:* {{incomplete type 'Incomplete' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'Incomplete' where a complete type is required}}
     std::atomic_fetch_sub(&obj, 0);
   }
   {
     std::atomic<Incomplete*> obj;
-    // expected-error@atomic:* {{incomplete type 'Incomplete' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'Incomplete' where a complete type is required}}
     std::atomic_fetch_sub(&obj, 0);
   }
 }
 
 void function_pointer() {
   {
     volatile std::atomic<void (*)(int)> fun;
-    // expected-error-re@atomic:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
+    // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
     std::atomic_fetch_sub(&fun, 0);
   }
   {
     std::atomic<void (*)(int)> fun;
-    // expected-error-re@atomic:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
+    // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
     std::atomic_fetch_sub(&fun, 0);
   }
 }
 
 struct S {
   void fun(int);
 };
 
 void member_function_pointer() {
   {
     volatile std::atomic<void (S::*)(int)> fun;
-    // expected-error@atomic:* {{no member named 'fetch_sub' in}}
+    // expected-error@*:* {{no member named 'fetch_sub' in}}
     std::atomic_fetch_sub(&fun, 0);
   }
   {
     std::atomic<void (S::*)(int)> fun;
-    // expected-error@atomic:* {{no member named 'fetch_sub' in}}
+    // expected-error@*:* {{no member named 'fetch_sub' in}}
     std::atomic_fetch_sub(&fun, 0);
   }
 }

libcxx/test/libcxx/atomics/atomics.types.operations/atomics.types.operations.req/atomic_fetch_sub_explicit.verify.cpp

 //     T*
 //     atomic_fetch_sub_explicit(atomic<T*>* obj, ptrdiff_t op, memory_order m);
 
 #include <atomic>
 
 void void_pointer() {
   {
     volatile std::atomic<void*> obj;
-    // expected-error@atomic:* {{incomplete type 'void' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'void' where a complete type is required}}
     std::atomic_fetch_sub_explicit(&obj, 0, std::memory_order_relaxed);
   }
   {
     std::atomic<void*> obj;
-    // expected-error@atomic:* {{incomplete type 'void' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'void' where a complete type is required}}
     std::atomic_fetch_sub_explicit(&obj, 0, std::memory_order_relaxed);
   }
 }
 
 struct Incomplete;
 
 void pointer_to_incomplete_type() {
   {
     volatile std::atomic<Incomplete*> obj;
-    // expected-error@atomic:* {{incomplete type 'Incomplete' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'Incomplete' where a complete type is required}}
     std::atomic_fetch_sub_explicit(&obj, 0, std::memory_order_relaxed);
   }
   {
     std::atomic<Incomplete*> obj;
-    // expected-error@atomic:* {{incomplete type 'Incomplete' where a complete type is required}}
+    // expected-error@*:* {{incomplete type 'Incomplete' where a complete type is required}}
     std::atomic_fetch_sub_explicit(&obj, 0, std::memory_order_relaxed);
   }
 }
 
 void function_pointer() {
   {
     volatile std::atomic<void (*)(int)> fun;
-    // expected-error-re@atomic:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
+    // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
     std::atomic_fetch_sub_explicit(&fun, 0, std::memory_order_relaxed);
   }
   {
     std::atomic<void (*)(int)> fun;
-    // expected-error-re@atomic:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
+    // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed due to requirement '!is_function<void (int)>::value'{{.*}}Pointer to function isn't allowed}}
     std::atomic_fetch_sub_explicit(&fun, 0, std::memory_order_relaxed);
   }
 }
 
 struct S {
   void fun(int);
 };
 
 void member_function_pointer() {
   {
     volatile std::atomic<void (S::*)(int)> fun;
-    // expected-error@atomic:* {{no member named 'fetch_sub' in}}
+    // expected-error@*:* {{no member named 'fetch_sub' in}}
     std::atomic_fetch_sub_explicit(&fun, 0, std::memory_order_relaxed);
   }
   {
     std::atomic<void (S::*)(int)> fun;
-    // expected-error@atomic:* {{no member named 'fetch_sub' in}}
+    // expected-error@*:* {{no member named 'fetch_sub' in}}
     std::atomic_fetch_sub_explicit(&fun, 0, std::memory_order_relaxed);
   }
 }

libcxx/test/libcxx/atomics/bit-int.verify.cpp

 // UNSUPPORTED: apple-clang-14
 
 // UNSUPPORTED: c++03
 
 #include <atomic>
 
 int main(int, char**)
 {
-  // expected-error@atomic:*1 {{_Atomic cannot be applied to integer type '_BitInt(32)'}}
+  // expected-error@*:*1 {{_Atomic cannot be applied to integer type '_BitInt(32)'}}
   std::atomic<_BitInt(32)> x(42);
 
   return 0;
 }

libcxx/test/libcxx/private_headers.verify.cpp

 #include <__algorithm/three_way_comp_ref_type.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/three_way_comp_ref_type.h'}}
 #include <__algorithm/transform.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/transform.h'}}
 #include <__algorithm/uniform_random_bit_generator_adaptor.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/uniform_random_bit_generator_adaptor.h'}}
 #include <__algorithm/unique.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/unique.h'}}
 #include <__algorithm/unique_copy.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/unique_copy.h'}}
 #include <__algorithm/unwrap_iter.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/unwrap_iter.h'}}
 #include <__algorithm/unwrap_range.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/unwrap_range.h'}}
 #include <__algorithm/upper_bound.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/upper_bound.h'}}
+#include <__atomic/aliases.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/aliases.h'}}
+#include <__atomic/atomic.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/atomic.h'}}
+#include <__atomic/atomic_base.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/atomic_base.h'}}
+#include <__atomic/atomic_flag.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/atomic_flag.h'}}
+#include <__atomic/atomic_init.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/atomic_init.h'}}
+#include <__atomic/atomic_lock_free.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/atomic_lock_free.h'}}
+#include <__atomic/atomic_sync.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/atomic_sync.h'}}
+#include <__atomic/check_memory_order.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/check_memory_order.h'}}
+#include <__atomic/contention_t.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/contention_t.h'}}
+#include <__atomic/cxx_atomic_impl.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/cxx_atomic_impl.h'}}
+#include <__atomic/fence.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/fence.h'}}
+#include <__atomic/is_always_lock_free.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/is_always_lock_free.h'}}
+#include <__atomic/kill_dependency.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/kill_dependency.h'}}
+#include <__atomic/memory_order.h> // expected-error@*:* {{use of private header from outside its module: '__atomic/memory_order.h'}}
 #include <__availability> // expected-error@*:* {{use of private header from outside its module: '__availability'}}
 #include <__bit/bit_cast.h> // expected-error@*:* {{use of private header from outside its module: '__bit/bit_cast.h'}}
 #include <__bit/bit_ceil.h> // expected-error@*:* {{use of private header from outside its module: '__bit/bit_ceil.h'}}
 #include <__bit/bit_floor.h> // expected-error@*:* {{use of private header from outside its module: '__bit/bit_floor.h'}}
 #include <__bit/bit_log2.h> // expected-error@*:* {{use of private header from outside its module: '__bit/bit_log2.h'}}
 #include <__bit/bit_width.h> // expected-error@*:* {{use of private header from outside its module: '__bit/bit_width.h'}}
 #include <__bit/blsr.h> // expected-error@*:* {{use of private header from outside its module: '__bit/blsr.h'}}
 #include <__bit/byteswap.h> // expected-error@*:* {{use of private header from outside its module: '__bit/byteswap.h'}}

libcxx/test/libcxx/transitive_includes/cxx03.csv

 array stdexcept
 array type_traits
 array utility
 array version
 atomic cmath
 atomic compare
 atomic cstddef
 atomic cstdint
+atomic cstdlib
 atomic cstring
 atomic ctime
 atomic iosfwd
 atomic limits
 atomic ratio
 atomic type_traits
 atomic version
 barrier atomic

libcxx/test/libcxx/transitive_includes/cxx11.csv

 array stdexcept
 array type_traits
 array utility
 array version
 atomic cmath
 atomic compare
 atomic cstddef
 atomic cstdint
+atomic cstdlib
 atomic cstring
 atomic ctime
 atomic iosfwd
 atomic limits
 atomic ratio
 atomic type_traits
 atomic version
 barrier atomic

libcxx/test/libcxx/transitive_includes/cxx14.csv

 array stdexcept
 array type_traits
 array utility
 array version
 atomic cmath
 atomic compare
 atomic cstddef
 atomic cstdint
+atomic cstdlib
 atomic cstring
 atomic ctime
 atomic iosfwd
 atomic limits
 atomic ratio
 atomic type_traits
 atomic version
 barrier atomic

libcxx/test/libcxx/transitive_includes/cxx17.csv

 array stdexcept
 array type_traits
 array utility
 array version
 atomic cmath
 atomic compare
 atomic cstddef
 atomic cstdint
+atomic cstdlib
 atomic cstring
 atomic ctime
 atomic iosfwd
 atomic limits
 atomic ratio
 atomic type_traits
 atomic version
 barrier atomic

libcxx/test/libcxx/transitive_includes/cxx20.csv

 array stdexcept
 array type_traits
 array utility
 array version
 atomic cmath
 atomic compare
 atomic cstddef
 atomic cstdint
+atomic cstdlib
 atomic cstring
 atomic ctime
 atomic iosfwd
 atomic limits
 atomic ratio
 atomic type_traits
 atomic version
 barrier atomic

libcxx/test/libcxx/transitive_includes/cxx2b.csv

 array cstdlib
 array initializer_list
 array limits
 array stdexcept
 array type_traits
 array version
 atomic cstddef
 atomic cstdint
+atomic cstdlib
 atomic cstring
 atomic ctime
 atomic iosfwd
 atomic limits
 atomic ratio
 atomic version
 barrier atomic
 barrier cstddef

libcxx/test/std/atomics/atomics.types.generic/trivially_copyable.verify.cpp

 struct NotTriviallyCopyable {
   explicit NotTriviallyCopyable(int i) : i_(i) { }
   NotTriviallyCopyable(const NotTriviallyCopyable &rhs) : i_(rhs.i_) { }
   int i_;
 };
 
 void f() {
   NotTriviallyCopyable x(42);
-  std::atomic<NotTriviallyCopyable> a(x); // expected-error@atomic:* {{std::atomic<T> requires that 'T' be a trivially copyable type}}
+  std::atomic<NotTriviallyCopyable> a(x); // expected-error@*:* {{std::atomic<T> requires that 'T' be a trivially copyable type}}
 }