[DO NOT COMMIT] Test if the libcxx CI system uses the updated clang compiler

[ChuanqiXu]

Summary

The content of this diff is the same as D109433. The CI's result of D109433 would fail all the way. It runs well locally. And from the error message from the CI, the reason looks like it didn't use the updated compiler. The intention of this diff is to test this.

[ChuanqiXu]

Emit an error if it find the compiler didn't implement __cpp_impl_coroutine macro. It should be implemented in ec11715.

[ChuanqiXu]

libcxx/include/coroutine

43–45

I added a check here to see if the compiler introduced macro __cpp_impl_coroutine, which should be introduced at https://github.com/llvm/llvm-project/commit/ec117158a390a0ebf64377caa5abd0c976df8f7a.

[ChuanqiXu]

Update again

[ChuanqiXu]

Test again

libcxx/docs/FeatureTestMacroTable.rst

.. table:: Current Status
     ``__cpp_lib_constexpr_string_view``               ``201811L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_constexpr_tuple``                     ``201811L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_constexpr_utility``                   ``201811L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_constexpr_vector``                    *unimplemented*
     ------------------------------------------------- -----------------
-    ``__cpp_lib_coroutine``                           *unimplemented*
+    ``__cpp_lib_coroutine``                           ``201902L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_destroying_delete``                   ``201806L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_endian``                              ``201907L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_erase_if``                            ``202002L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_execution``                           *unimplemented*

libcxx/docs/Status/Cxx20Issues.csv

 "`3382 <https://wg21.link/LWG3382>`__","NTTP for ``pair``\  and ``array``\ ","Prague","",""
 "`3383 <https://wg21.link/LWG3383>`__","|sect|\ [time.zone.leap.nonmembers] ``sys_seconds``\  should be replaced with ``seconds``\ ","Prague","","","|chrono|"
 "`3384 <https://wg21.link/LWG3384>`__","``transform_view::*sentinel*``\  has an incorrect ``operator-``\ ","Prague","","","|ranges|"
 "`3385 <https://wg21.link/LWG3385>`__","``common_iterator``\  is not sufficiently constrained for non-copyable iterators","Prague","","","|ranges|"
 "`3387 <https://wg21.link/LWG3387>`__","|sect|\ [range.reverse.view] ``reverse_view<V>``\  unintentionally requires ``range<const V>``\ ","Prague","","","|ranges|"
 "`3388 <https://wg21.link/LWG3388>`__","``view``\  iterator types have ill-formed ``<=>``\  operators","Prague","","","|ranges|"
 "`3389 <https://wg21.link/LWG3389>`__","A move-only iterator still does not have a ``counted_iterator``\ ","Prague","","","|ranges|"
 "`3390 <https://wg21.link/LWG3390>`__","``make_move_iterator()``\  cannot be used to construct a ``move_iterator``\  for a move-only iterator","Prague","","","|ranges|"
-"`3393 <https://wg21.link/LWG3393>`__","Missing/incorrect feature test macro for coroutines","Prague","",""
+"`3393 <https://wg21.link/LWG3393>`__","Missing/incorrect feature test macro for coroutines","Prague","|Complete|","14.0"
 "`3395 <https://wg21.link/LWG3395>`__","Definition for three-way comparison needs to be updated (US 152)","Prague","","","|spaceship|"
 "`3396 <https://wg21.link/LWG3396>`__","Clarify point of reference for ``source_location::current()``\  (DE 169)","Prague","",""
 "`3397 <https://wg21.link/LWG3397>`__","``ranges::basic_istream_view::iterator``\  should not provide ``iterator_category``\ ","Prague","","","|ranges|"
 "`3398 <https://wg21.link/LWG3398>`__","``tuple_element_t``\  is also wrong for ``const subrange``\ ","Prague","|Complete|","14.0","|ranges|"
 "`3446 <https://wg21.link/LWG3446>`__","``indirectly_readable_traits``\ ambiguity for types with both ``value_type``\ and ``element_type``\ ","November virtual meeting","|Complete|","13.0"

libcxx/docs/Status/SpaceshipProjects.csv

 Section,Description,Dependencies,Assignee,Complete
 | `[cmp.concept] <https://wg21.link/cmp.concept>`_,"| `three_way_comparable <https://reviews.llvm.org/D103478>`_
 | `three_way_comparable_with <https://reviews.llvm.org/D103478>`_",None,Ruslan Arutyunyan,|In Progress|
 | `[cmp.result] <https://wg21.link/cmp.result>`_,| `compare_three_way_result <https://reviews.llvm.org/D103581>`_,None,Arthur O'Dwyer,|Complete|
 | `[expos.only.func] <https://wg21.link/expos.only.func>`_,"| `synth-three-way <https://reviews.llvm.org/D107721>`_
 | `synth-three-way-result <https://reviews.llvm.org/D107721>`_",[cmp.concept],Kent Ross,|Complete|
 | `[comparisons.three.way] <https://wg21.link/comparisons.three.way>`_,| `compare_three_way <https://reviews.llvm.org/D80899>`_,[cmp.concept],Arthur O'Dwyer,|Complete|
 | `[cmp.alg] <https://wg21.link/cmp.alg>`_,"| `strong_order <https://reviews.llvm.org/D107036>`_
 | `weak_order <https://reviews.llvm.org/D107036>`_
 | `partial_order <https://reviews.llvm.org/D107036>`_",None,Arthur O'Dwyer,|In Progress|
 | `[alg.three.way] <https://wg21.link/alg.three.way>`_,| `lexicographical_compare_three_way <https://reviews.llvm.org/D80902>`_,[comparisons.three.way],Christopher Di Bella,|In Progress|
-| `[coroutine.handle.compare] <https://wg21.link/coroutine.handle.compare>`_,| coroutine_handle,[comparisons.three.way],Unassigned,|Not Started|
+| `[coroutine.handle.compare] <https://wg21.link/coroutine.handle.compare>`_,| coroutine_handle,[comparisons.three.way],Unassigned,|Complete|
 | `[pairs.spec] <https://wg21.link/pairs.spec>`_,| `pair <https://reviews.llvm.org/D107721>`_,[expos.only.func],Kent Ross,|Complete|
 | `[syserr.errcat.nonvirtuals] <https://wg21.link/syserr.errcat.nonvirtuals>`_,| error_category,[comparisons.three.way],Unassigned,|Not Started|
 | `[syserr.compare] <https://wg21.link/syserr.compare>`_,"| error_code
 | error_condition",None,Unassigned,|Not Started|
 | `[tuple.rel] <https://wg21.link/tuple.rel>`_,| `tuple <https://reviews.llvm.org/D108250>`_,[expos.only.func],Kent Ross,|Complete|
 "| `[optional.relops] <https://wg21.link/optional.relops>`_
 | `[optional.nullops] <https://wg21.link/optional.nullops>`_
 | `[optional.comp.with.t] <https://wg21.link/optional.comp.with.t>`_","| optional

libcxx/include/CMakeLists.txt

set(files
   __concepts/predicate.h
   __concepts/regular.h
   __concepts/relation.h
   __concepts/same_as.h
   __concepts/semiregular.h
   __concepts/swappable.h
   __concepts/totally_ordered.h
   __config
+  __coroutine/coroutine_handle.h
+  __coroutine/noop_coroutine_handle.h
+  __coroutine/coroutine_traits.h
+  __coroutine/coroutine_trivial_awaitables.h
   __debug
   __errc
   __format/format_arg.h
   __format/format_args.h
   __format/format_context.h
   __format/format_error.h
   __format/format_fwd.h
   __format/format_parse_context.h
set(files
   clocale
   cmath
   codecvt
   compare
   complex
   complex.h
   concepts
   condition_variable
+  coroutine
   csetjmp
   csignal
   cstdarg
   cstdbool
   cstddef
   cstdint
   cstdio
   cstdlib

libcxx/include/__config

 #if defined(_LIBCPP_ENABLE_CXX20_REMOVED_FEATURES)
 #define _LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS
 #define _LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS
 #define _LIBCPP_ENABLE_CXX20_REMOVED_NEGATORS
 #define _LIBCPP_ENABLE_CXX20_REMOVED_RAW_STORAGE_ITERATOR
 #define _LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS
 #endif // _LIBCPP_ENABLE_CXX20_REMOVED_FEATURES
 
-#if !defined(__cpp_coroutines) || __cpp_coroutines < 201703L
-#define _LIBCPP_HAS_NO_COROUTINES
+#if !defined(__cpp_impl_coroutine) || __cpp_impl_coroutine < 201902L
+#define _LIBCPP_HAS_NO_CXX20_COROUTINES
 #endif
 
 #if !defined(__cpp_impl_three_way_comparison) || __cpp_impl_three_way_comparison < 201907L
 #define _LIBCPP_HAS_NO_SPACESHIP_OPERATOR
 #endif
 
 #if defined(_LIBCPP_COMPILER_IBM)
 #define _LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO

libcxx/include/__coroutine/coroutine_handle.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___COROUTINE_COROUTINE_HANDLE_H
+#define _LIBCPP___COROUTINE_COROUTINE_HANDLE_H
+
+#include <__config>
+#include <__debug>
+#include <__functional/hash.h>
+#include <__memory/addressof.h>
+#include <compare>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CXX20_COROUTINES)
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// [coroutine.handle]
+template <class _Promise = void>
+struct _LIBCPP_TEMPLATE_VIS coroutine_handle;
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS coroutine_handle<void> {
+public:
+    // [coroutine.handle.con], construct/reset
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr coroutine_handle() noexcept = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr coroutine_handle(nullptr_t) noexcept {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    coroutine_handle& operator=(nullptr_t) noexcept {
+        __handle_ = nullptr;
+        return *this;
+    }
+
+    // [coroutine.handle.export.import], export/import
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void* address() const noexcept { return __handle_; }
+
+    _LIBCPP_HIDE_FROM_ABI
+    static constexpr coroutine_handle from_address(void* __addr) noexcept {
+        coroutine_handle __tmp;
+        __tmp.__handle_ = __addr;
+        return __tmp;
+    }
+
+    // [coroutine.handle.observers], observers
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit operator bool() const noexcept {
+        return __handle_ != nullptr;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    bool done() const {
+        _LIBCPP_ASSERT(__is_suspended(), "done() can be called only on suspended coroutines");
+        return __builtin_coro_done(__handle_);
+    }
+
+    // [coroutine.handle.resumption], resumption
+    _LIBCPP_HIDE_FROM_ABI
+    void operator()() const { resume(); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    void resume() const {
+        _LIBCPP_ASSERT(__is_suspended(), "resume() can be called only on suspended coroutines");
+        _LIBCPP_ASSERT(!done(), "resume() has undefined behavior when the coroutine is done");
+        __builtin_coro_resume(__handle_);
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    void destroy() const {
+        _LIBCPP_ASSERT(__is_suspended(), "destroy() can be called only on suspended coroutines");
+        __builtin_coro_destroy(__handle_);
+    }
+
+private:
+    bool __is_suspended() const {
+        // FIXME actually implement a check for if the coro is suspended.
+        return __handle_ != nullptr;
+    }
+
+    void* __handle_ = nullptr;
+};
+
+// [coroutine.handle.compare]
+#if defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR)
+
+inline _LIBCPP_HIDE_FROM_ABI
+constexpr bool operator==(coroutine_handle<> __x, coroutine_handle<> __y) noexcept {
+    return __x.address() == __y.address();
+}
+inline _LIBCPP_HIDE_FROM_ABI
+constexpr bool operator<(coroutine_handle<> __x, coroutine_handle<> __y) noexcept {
+    return less<void*>()(__x.address(), __y.address());
+}
+inline _LIBCPP_HIDE_FROM_ABI
+constexpr bool operator>(coroutine_handle<> __x, coroutine_handle<> __y) noexcept {
+    return __y < __x;
+}
+inline _LIBCPP_HIDE_FROM_ABI
+constexpr bool operator<=(coroutine_handle<> __x, coroutine_handle<> __y) noexcept {
+    return !(__x > __y);
+}
+inline _LIBCPP_HIDE_FROM_ABI
+constexpr bool operator>=(coroutine_handle<> __x, coroutine_handle<> __y) noexcept {
+    return !(__x < __y);
+}
+
+#else
+
+inline _LIBCPP_HIDE_FROM_ABI
+constexpr bool operator==(coroutine_handle<> __x, coroutine_handle<> __y) noexcept {
+    return __x.address() == __y.address();
+}
+inline _LIBCPP_HIDE_FROM_ABI
+constexpr strong_ordering operator<=>(coroutine_handle<> __x, coroutine_handle<> __y) noexcept {
+    return compare_three_way()(__x.address(), __y.address());
+}
+
+#endif // defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR)
+
+template <class _Promise>
+struct _LIBCPP_TEMPLATE_VIS coroutine_handle {
+public:
+    // [coroutine.handle.con], construct/reset
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr coroutine_handle() noexcept = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr coroutine_handle(nullptr_t) noexcept {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    static coroutine_handle from_promise(_Promise& __promise) {
+        using _RawPromise = typename remove_cv<_Promise>::type;
+        coroutine_handle __tmp;
+        __tmp.__handle_ =
+            __builtin_coro_promise(_VSTD::addressof(const_cast<_RawPromise&>(__promise)), alignof(_Promise), true);
+        return __tmp;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    coroutine_handle& operator=(nullptr_t) noexcept {
+        __handle_ = nullptr;
+        return *this;
+    }
+
+    // [coroutine.handle.export.import], export/import
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void* address() const noexcept { return __handle_; }
+
+    _LIBCPP_HIDE_FROM_ABI
+    static constexpr coroutine_handle from_address(void* __addr) noexcept {
+        coroutine_handle __tmp;
+        __tmp.__handle_ = __addr;
+        return __tmp;
+    }
+
+    // [coroutine.handle.conv], conversion
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr operator coroutine_handle<>() const noexcept {
+        return coroutine_handle<>::from_address(address());
+    }
+
+    // [coroutine.handle.observers], observers
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit operator bool() const noexcept {
+        return __handle_ != nullptr;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    bool done() const {
+        _LIBCPP_ASSERT(__is_suspended(), "done() can be called only on suspended coroutines");
+        return __builtin_coro_done(__handle_);
+    }
+
+    // [coroutine.handle.resumption], resumption
+    _LIBCPP_HIDE_FROM_ABI
+    void operator()() const { resume(); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    void resume() const {
+        _LIBCPP_ASSERT(__is_suspended(), "resume() can be called only on suspended coroutines");
+        _LIBCPP_ASSERT(!done(), "resume() has undefined behavior when the coroutine is done");
+        __builtin_coro_resume(__handle_);
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    void destroy() const {
+        _LIBCPP_ASSERT(__is_suspended(), "destroy() can be called only on suspended coroutines");
+        __builtin_coro_destroy(__handle_);
+    }
+
+    // [coroutine.handle.promise], promise access
+    _LIBCPP_HIDE_FROM_ABI
+    _Promise& promise() const {
+        return *static_cast<_Promise*>(__builtin_coro_promise(this->__handle_, alignof(_Promise), false));
+    }
+
+private:
+    bool __is_suspended() const {
+        // FIXME actually implement a check for if the coro is suspended.
+        return __handle_ != nullptr;
+    }
+    void* __handle_ = nullptr;
+};
+
+// [coroutine.handle.hash]
+template <class _Tp>
+struct hash<coroutine_handle<_Tp>> {
+    _LIBCPP_HIDE_FROM_ABI
+    size_t operator()(const coroutine_handle<_Tp>& __v) const noexcept { return hash<void*>()(__v.address()); }
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // __LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CXX20_COROUTINES)
+
+#endif // _LIBCPP___COROUTINE_COROUTINE_HANDLE_H

libcxx/include/__coroutine/coroutine_traits.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___COROUTINE_COROUTINE_TRAITS_H
+#define _LIBCPP___COROUTINE_COROUTINE_TRAITS_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CXX20_COROUTINES)
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// [coroutine.traits]
+// [coroutine.traits.primary]
+//   The header <coroutine> defined the primary template coroutine_traits such that
+// if ArgTypes is a parameter pack of types and if the qualified-id R::promise_type
+// is valid and denotes a type ([temp.deduct]), then coroutine_traits<R, ArgTypes...>
+// has the following publicly accessible memebr:
+//
+//    using promise_type = typename R::promise_type;
+//
+// Otherwise, coroutine_traits<R, ArgTypes...> has no members.
+template <class _Tp, class = void>
+struct __coroutine_traits_sfinae {};
+
+template <class _Tp>
+struct __coroutine_traits_sfinae<
+    _Tp, typename __void_t<typename _Tp::promise_type>::type>
+{
+  using promise_type = typename _Tp::promise_type;
+};
+
+template <class _Ret, class... _Args>
+struct coroutine_traits
+    : public __coroutine_traits_sfinae<_Ret>
+{
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // __LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CXX20_COROUTINES)
+
+#endif // _LIBCPP___COROUTINE_COROUTINE_TRAITS_H

libcxx/include/__coroutine/coroutine_trivial_awaitables.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___COROUTINE_TRIVIAL_AWAITABLES_H
+#define __LIBCPP___COROUTINE_TRIVIAL_AWAITABLES_H
+
+#include <__config>
+#include <__coroutine/coroutine_handle.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CXX20_COROUTINES)
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// [coroutine.trivial.awaitables]
+struct suspend_never {
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr bool await_ready() const noexcept { return true; }
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void await_suspend(coroutine_handle<>) const noexcept {}
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void await_resume() const noexcept {}
+};
+
+struct suspend_always {
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr bool await_ready() const noexcept { return false; }
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void await_suspend(coroutine_handle<>) const noexcept {}
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void await_resume() const noexcept {}
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // __LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CXX20_COROUTINES)
+
+#endif // __LIBCPP___COROUTINE_TRIVIAL_AWAITABLES_H

libcxx/include/__coroutine/noop_coroutine_handle.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___COROUTINE_NOOP_COROUTINE_HANDLE_H
+#define _LIBCPP___COROUTINE_NOOP_COROUTINE_HANDLE_H
+
+#include <__config>
+#include <__coroutine/coroutine_handle.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CXX20_COROUTINES)
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if __has_builtin(__builtin_coro_noop)
+// [coroutine.noop]
+// [coroutine.promise.noop]
+struct noop_coroutine_promise {};
+
+// [coroutine.handle.noop]
+template <>
+struct _LIBCPP_TEMPLATE_VIS coroutine_handle<noop_coroutine_promise> {
+public:
+    // [coroutine.handle.noop.conv], conversion
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr operator coroutine_handle<>() const noexcept {
+        return coroutine_handle<>::from_address(address());
+    }
+
+    // [coroutine.handle.noop.observers], observers
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit operator bool() const noexcept { return true; }
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr bool done() const noexcept { return false; }
+
+    // [coroutine.handle.noop.resumption], resumption
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void operator()() const noexcept {}
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void resume() const noexcept {}
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void destroy() const noexcept {}
+
+    // [coroutine.handle.noop.promise], promise access
+    _LIBCPP_HIDE_FROM_ABI
+    noop_coroutine_promise& promise() const noexcept {
+        return *static_cast<noop_coroutine_promise*>(
+            __builtin_coro_promise(this->__handle_, alignof(noop_coroutine_promise), false));
+    }
+
+    // [coroutine.handle.noop.address], address
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void* address() const noexcept { return __handle_; }
+
+private:
+    _LIBCPP_HIDE_FROM_ABI
+    friend coroutine_handle<noop_coroutine_promise> noop_coroutine() noexcept;
+
+    _LIBCPP_HIDE_FROM_ABI coroutine_handle() noexcept { 
+        this->__handle_ = __builtin_coro_noop();
+    }
+
+    void* __handle_ = nullptr;
+};
+
+using noop_coroutine_handle = coroutine_handle<noop_coroutine_promise>;
+
+// [coroutine.noop.coroutine]
+inline _LIBCPP_HIDE_FROM_ABI
+noop_coroutine_handle noop_coroutine() noexcept { return noop_coroutine_handle(); }
+
+#endif // __has_builtin(__builtin_coro_noop)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // __LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CXX20_COROUTINES)
+
+#endif // _LIBCPP___COROUTINE_NOOP_COROUTINE_HANDLE_H

libcxx/include/coroutine

+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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_COROUTINE
+#define _LIBCPP_COROUTINE
+
+/**
+    coroutine synopsis
+
+namespace std {
+// [coroutine.traits]
+template <class R, class... ArgTypes>
+  struct coroutine_traits;
+// [coroutine.handle]
+template <class Promise = void>
+  struct coroutine_handle;
+// [coroutine.handle.compare]
+constexpr bool operator==(coroutine_handle<> x, coroutine_handle<> y) noexcept;
+constexpr strong_ordering operator<=>(coroutine_handle<> x, coroutine_handle<> y) noexcept;
+// [coroutine.handle.hash]
+template <class T> struct hash;
+template <class P> struct hash<coroutine_handle<P>>;
+// [coroutine.noop]
+struct noop_coroutine_promise;
+template<> struct coroutine_handle<noop_coroutine_promise>;
+using noop_coroutine_handle = coroutine_handle<noop_coroutine_promise>;
+noop_coroutine_handle noop_coroutine() noexcept;
+// [coroutine.trivial.awaitables]
+struct suspend_never;
+struct suspend_always;
+} // namespace std
+
+ */
+
+#include <__config>
+
+#if !defined(__cpp_impl_coroutine) || __cpp_impl_coroutine < 201902L
+#error "The compiler version is not right. It didn't implement macro __cpp_impl_coroutine."
+#endif
+
+#include <__coroutine/coroutine_handle.h>
+#include <__coroutine/noop_coroutine_handle.h>
+#include <__coroutine/coroutine_traits.h>
+#include <__coroutine/coroutine_trivial_awaitables.h>
+
+#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
+#pragma GCC system_header
+#endif
+
+#endif // _LIBCPP_COROUTINE

libcxx/include/experimental/__config

 
 #define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_FILESYSTEM \
     _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL namespace filesystem _LIBCPP_DEPRECATED_EXPERIMENTAL_FILESYSTEM { \
     inline namespace v1 {
 
 #define _LIBCPP_END_NAMESPACE_EXPERIMENTAL_FILESYSTEM \
     } } _LIBCPP_END_NAMESPACE_EXPERIMENTAL
 
+#if !defined(__cpp_coroutines) || __cpp_coroutines < 201703L
+#define _LIBCPP_HAS_NO_EXPERIMENTAL_COROUTINES
+#endif
+
 #define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_COROUTINES \
   _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace coroutines_v1 {
 
 #define _LIBCPP_END_NAMESPACE_EXPERIMENTAL_COROUTINES \
   } _LIBCPP_END_NAMESPACE_EXPERIMENTAL
 
 #define _VSTD_CORO _VSTD_EXPERIMENTAL::coroutines_v1
 

libcxx/include/experimental/coroutine

 #include <memory> // for hash<T*>
 #include <cstddef>
 #include <__debug>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
 
-#ifdef _LIBCPP_HAS_NO_COROUTINES
+#ifdef _LIBCPP_HAS_NO_EXPERIMENTAL_COROUTINES
 # if defined(_LIBCPP_WARNING)
     _LIBCPP_WARNING("<experimental/coroutine> cannot be used with this compiler")
 # else
 #   warning <experimental/coroutine> cannot be used with this compiler
 # endif
 #endif
 
-#ifndef _LIBCPP_HAS_NO_COROUTINES
+#ifndef _LIBCPP_HAS_NO_EXPERIMENTAL_COROUTINES
 
 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_COROUTINES
 
 template <class _Tp, class = void>
 struct __coroutine_traits_sfinae {};
 
 template <class _Tp>
 struct __coroutine_traits_sfinae<
struct hash<_VSTD_CORO::coroutine_handle<_Tp> > {
     using __arg_type = _VSTD_CORO::coroutine_handle<_Tp>;
     _LIBCPP_INLINE_VISIBILITY
     size_t operator()(__arg_type const& __v) const _NOEXCEPT
     {return hash<void*>()(__v.address());}
 };
 
 _LIBCPP_END_NAMESPACE_STD
 
-#endif // !defined(_LIBCPP_HAS_NO_COROUTINES)
+#endif // !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_COROUTINES)
 
 #endif /* _LIBCPP_EXPERIMENTAL_COROUTINE */

libcxx/include/module.modulemap

module __concepts {
       module swappable                  { private header "__concepts/swappable.h"                 }
       module totally_ordered            { private header "__concepts/totally_ordered.h"           }
     }
   }
   module condition_variable {
     header "condition_variable"
     export *
   }
+  module coroutine {
+    requires coroutines
+    header "coroutine"
+    export *
+
+    module __coroutine {
+      module coroutine_handle             { private header "__coroutine/coroutine_handle.h"             }
+      module coroutine_noop               { private header "__coroutine/noop_coroutine_handle.h"        }
+      module coroutine_traits             { private header "__coroutine/coroutine_traits.h"             }
+      module coroutine_trivial_awaitables { private header "__coroutine/coroutine_trivial_awaitables.h" }
+    }
+  }
   module deque {
     header "deque"
     export initializer_list
     export *
   }
   module exception {
     header "exception"
     export *

libcxx/include/version

 # define __cpp_lib_constexpr_iterator                   201811L
 # define __cpp_lib_constexpr_memory                     201811L
 # define __cpp_lib_constexpr_numeric                    201911L
 # define __cpp_lib_constexpr_string                     201811L
 # define __cpp_lib_constexpr_string_view                201811L
 # define __cpp_lib_constexpr_tuple                      201811L
 # define __cpp_lib_constexpr_utility                    201811L
 // # define __cpp_lib_constexpr_vector                     201907L
-// # define __cpp_lib_coroutine                            201902L
+# define __cpp_lib_coroutine                            201902L
 # if _LIBCPP_STD_VER > 17 && defined(__cpp_impl_destroying_delete) && __cpp_impl_destroying_delete >= 201806L
 #   define __cpp_lib_destroying_delete                  201806L
 # endif
 # define __cpp_lib_endian                               201907L
 # define __cpp_lib_erase_if                             202002L
 # undef  __cpp_lib_execution
 // # define __cpp_lib_execution                            201902L
 # if !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)

libcxx/test/libcxx/diagnostics/detail.headers/coroutine/coroutine_handle.module.verify.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: modules-build
+
+// WARNING: This test was generated by 'generate_private_header_tests.py'
+// and should not be edited manually.
+
+// expected-error@*:* {{use of private header from outside its module: '__coroutine/coroutine_handle.h'}}
+#include <__coroutine/coroutine_handle.h>

libcxx/test/libcxx/diagnostics/detail.headers/coroutine/coroutine_traits.module.verify.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: modules-build
+
+// WARNING: This test was generated by 'generate_private_header_tests.py'
+// and should not be edited manually.
+
+// expected-error@*:* {{use of private header from outside its module: '__coroutine/coroutine_traits.h'}}
+#include <__coroutine/coroutine_traits.h>

libcxx/test/libcxx/diagnostics/detail.headers/coroutine/coroutine_trivial_awaitables.module.verify.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: modules-build
+
+// WARNING: This test was generated by 'generate_private_header_tests.py'
+// and should not be edited manually.
+
+// expected-error@*:* {{use of private header from outside its module: '__coroutine/coroutine_trivial_awaitables.h'}}
+#include <__coroutine/coroutine_trivial_awaitables.h>

libcxx/test/libcxx/diagnostics/detail.headers/coroutine/noop_coroutine_handle.module.verify.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: modules-build
+
+// WARNING: This test was generated by 'generate_private_header_tests.py'
+// and should not be edited manually.
+
+// expected-error@*:* {{use of private header from outside its module: '__coroutine/noop_coroutine_handle.h'}}
+#include <__coroutine/noop_coroutine_handle.h>

libcxx/test/libcxx/double_include.sh.cpp

 #ifndef _LIBCPP_HAS_NO_LOCALIZATION
 #    include <codecvt>
 #endif
 #include <compare>
 #include <complex>
 #include <complex.h>
 #include <concepts>
 #include <condition_variable>
+#if defined(__cpp_impl_coroutine)
+#    include <coroutine>
+#endif
 #include <csetjmp>
 #include <csignal>
 #include <cstdarg>
 #include <cstdbool>
 #include <cstddef>
 #include <cstdint>
 #include <cstdio>
 #include <cstdlib>

libcxx/test/libcxx/inclusions/coroutine.inclusions.compile.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// WARNING: This test was generated by generate_header_inclusion_tests.py
+// and should not be edited manually.
+//
+// clang-format off
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <coroutine>
+
+// Test that <coroutine> includes all the other headers it's supposed to.
+
+#include <coroutine>
+#include "test_macros.h"
+
+#if !defined(_LIBCPP_COROUTINE)
+ #   error "<coroutine> was expected to define _LIBCPP_COROUTINE"
+#endif
+#if TEST_STD_VER > 17 && !defined(_LIBCPP_COMPARE)
+ #   error "<coroutine> should include <compare> in C++20 and later"
+#endif

libcxx/test/libcxx/min_max_macros.compile.pass.cpp

 #include <complex>
 TEST_MACROS();
 #include <complex.h>
 TEST_MACROS();
 #include <concepts>
 TEST_MACROS();
 #include <condition_variable>
 TEST_MACROS();
+#if defined(__cpp_impl_coroutine)
+#    include <coroutine>
+TEST_MACROS();
+#endif
 #include <csetjmp>
 TEST_MACROS();
 #include <csignal>
 TEST_MACROS();
 #include <cstdarg>
 TEST_MACROS();
 #include <cstdbool>
 TEST_MACROS();

libcxx/test/libcxx/no_assert_include.compile.pass.cpp

 #ifndef _LIBCPP_HAS_NO_LOCALIZATION
 #    include <codecvt>
 #endif
 #include <compare>
 #include <complex>
 #include <complex.h>
 #include <concepts>
 #include <condition_variable>
+#if defined(__cpp_impl_coroutine)
+#    include <coroutine>
+#endif
 #include <csetjmp>
 #include <csignal>
 #include <cstdarg>
 #include <cstdbool>
 #include <cstddef>
 #include <cstdint>
 #include <cstdio>
 #include <cstdlib>

libcxx/test/std/experimental/language.support/support.coroutines/end.to.end/generator.pass.cpp

 // See https://llvm.org/PR33271
 // UNSUPPORTED: ubsan
 
 #include <experimental/coroutine>
 #include <vector>
 #include <cassert>
 
 #include "test_macros.h"
-#include "coroutine_types.h"
 
-using namespace std::experimental;
+
+template <typename Ty> struct generator {
+  struct promise_type {
+    Ty current_value;
+    std::experimental::suspend_always yield_value(Ty value) {
+      this->current_value = value;
+      return {};
+    }
+    std::experimental::suspend_always initial_suspend() { return {}; }
+    std::experimental::suspend_always final_suspend() noexcept { return {}; }
+    generator get_return_object() { return generator{this}; };
+    void return_void() {}
+    void unhandled_exception() {}
+  };
+
+  struct iterator {
+    std::experimental::coroutine_handle<promise_type> _Coro;
+    bool _Done;
+
+    iterator(std::experimental::coroutine_handle<promise_type> Coro, bool Done)
+        : _Coro(Coro), _Done(Done) {}
+
+    iterator &operator++() {
+      _Coro.resume();
+      _Done = _Coro.done();
+      return *this;
+    }
+
+    bool operator==(iterator const &_Right) const {
+      return _Done == _Right._Done;
+    }
+
+    bool operator!=(iterator const &_Right) const { return !(*this == _Right); }
+
+    Ty const &operator*() const { return _Coro.promise().current_value; }
+
+    Ty const *operator->() const { return &(operator*()); }
+  };
+
+  iterator begin() {
+    p.resume();
+    return {p, p.done()};
+  }
+
+  iterator end() { return {p, true}; }
+
+  generator(generator &&rhs) : p(rhs.p) { rhs.p = nullptr; }
+
+  ~generator() {
+    if (p)
+      p.destroy();
+  }
+
+private:
+  explicit generator(promise_type *p)
+      : p(std::experimental::coroutine_handle<promise_type>::from_promise(*p)) {}
+
+  std::experimental::coroutine_handle<promise_type> p;
+};
 
 struct minig {
   struct promise_type {
     int current_value;
-    suspend_always yield_value(int value) {
+    std::experimental::suspend_always yield_value(int value) {
       this->current_value = value;
       return {};
     }
-    suspend_always initial_suspend() { return {}; }
-    suspend_always final_suspend() noexcept { return {}; }
+    std::experimental::suspend_always initial_suspend() { return {}; }
+    std::experimental::suspend_always final_suspend() noexcept { return {}; }
     minig get_return_object() { return minig{this}; };
     void return_void() {}
     void unhandled_exception() {}
   };
 
   bool move_next() {
     p.resume();
     return !p.done();
   }
   int current_value() { return p.promise().current_value; }
 
   minig(minig &&rhs) : p(rhs.p) { rhs.p = nullptr; }
 
   ~minig() {
     if (p)
       p.destroy();
   }
 
 private:
   explicit minig(promise_type *p)
-      : p(coroutine_handle<promise_type>::from_promise(*p)) {}
+      : p(std::experimental::coroutine_handle<promise_type>::from_promise(*p)) {}
 
-  coroutine_handle<promise_type> p;
+  std::experimental::coroutine_handle<promise_type> p;
 };
 
 
 minig mini_count(int n) {
   for (int i = 0; i < n; i++) {
     co_yield i;
   }
 }

libcxx/test/std/language.support/support.coroutines/coroutine.handle/coroutine.handle.hash/hash.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <coroutine>
+
+// template <class Promise = void>
+// struct coroutine_handle;
+
+// namespace std {
+//  template <class P> struct hash<coroutine_handle<P>>;
+// }
+
+#include <coroutine>
+#include <type_traits>
+#include <memory>
+#include <utility>
+#include <cstdint>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class C>
+void do_test(int *LHSVal, int *RHSVal) {
+  const size_t ExpectLHS = std::hash<void*>{}((LHSVal));
+  const size_t ExpectRHS = std::hash<void*>{}((RHSVal));
+  const C LHS = C::from_address((LHSVal));
+  const C RHS = C::from_address((RHSVal));
+  const std::hash<C> h;
+
+  LIBCPP_ASSERT(h(LHS) == ExpectLHS);
+  LIBCPP_ASSERT(h(RHS) == ExpectRHS);
+  assert((h(LHS) == h(RHS)) == (LHSVal == RHSVal));
+  {
+    ASSERT_SAME_TYPE(decltype(h(LHS)), size_t);
+    ASSERT_NOEXCEPT(std::hash<C>{}(LHS));
+  }
+}
+
+int main(int, char**)
+{
+  int i, j;
+  std::pair<int *, int *> const TestCases[] = {
+      {nullptr, nullptr},
+      {nullptr, &i},
+      {&i, &i},
+      {&i, &j}
+  };
+  for (auto& TC : TestCases) {
+    do_test<std::coroutine_handle<>>(TC.first, TC.second);
+    do_test<std::coroutine_handle<int>>(TC.first, TC.second);
+  }
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.handle/coroutine.handle.capacity/operator_bool.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <coroutine>
+
+// template <class Promise = void>
+// struct coroutine_handle;
+
+// constexpr explicit operator bool() const noexcept
+
+#include <coroutine>
+#include <type_traits>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class C>
+constexpr bool do_test() {
+  static_assert(std::is_nothrow_constructible<bool, C>::value, "");
+  static_assert(!std::is_convertible<C, bool>::value, "");
+  {
+    constexpr C c;
+    static_assert(bool(c) == false, "");
+  }
+  { // null case
+    const C c = {};
+    ASSERT_NOEXCEPT(bool(c));
+    assert(c.address() == nullptr);
+    assert(bool(c) == false);
+  }
+  { // non-null case
+    char dummy = 42;
+    C c = C::from_address((void*)&dummy);
+    assert(c.address() == &dummy);
+    assert(bool(c) == true);
+  }
+  return true;
+}
+
+int main(int, char**)
+{
+  do_test<std::coroutine_handle<>>();
+  do_test<std::coroutine_handle<int>>();
+  static_assert(do_test<std::coroutine_handle<>>());
+  static_assert(do_test<std::coroutine_handle<int>>());
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.handle/coroutine.handle.compare/equal_comp.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <coroutine>
+
+// template <class Promise = void>
+// struct coroutine_handle;
+
+// constexpr bool operator==(coroutine_handle<> x, coroutine_handle<> y) noexcept;
+
+#include <coroutine>
+#include <type_traits>
+#include <utility>
+#include <cstdint>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class C>
+void do_test(int *LHSVal, int *RHSVal) {
+  const C LHS = C::from_address(LHSVal);
+  const C RHS = C::from_address(RHSVal);
+  const bool ExpectIsEqual = (LHSVal == RHSVal);
+  assert((LHS == RHS) == ExpectIsEqual);
+  assert((RHS == LHS) == ExpectIsEqual);
+  assert((LHS != RHS) == !ExpectIsEqual);
+  assert((RHS != LHS) == !ExpectIsEqual);
+  {
+    static_assert(noexcept(LHS == RHS), "");
+    static_assert(noexcept(LHS != RHS), "");
+    ASSERT_SAME_TYPE(decltype(LHS == RHS), bool);
+    ASSERT_SAME_TYPE(decltype(LHS != RHS), bool);
+  }
+}
+
+int main(int, char**)
+{
+  int i;
+  std::pair<int *, int *> const TestCases[] = {
+      {nullptr, nullptr},
+      {&i, &i},
+      {nullptr, &i},
+      {&i, nullptr}
+  };
+  for (auto& TC : TestCases) {
+    do_test<std::coroutine_handle<>>(TC.first, TC.second);
+    do_test<std::coroutine_handle<int>>(TC.first, TC.second);
+  }
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.handle/coroutine.handle.compare/less_comp.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <coroutine>
+
+// template <class Promise = void>
+// struct coroutine_handle;
+
+// constexpr strong_ordering operator<=>(coroutine_handle<> x, coroutine_handle<> y) noexcept;
+
+#include <coroutine>
+#include <type_traits>
+#include <utility>
+#include <cstdint>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class C>
+void do_test(int *LHSVal, int *RHSVal) {
+  const C LHS = C::from_address(LHSVal);
+  const C RHS = C::from_address(RHSVal);
+  assert((LHS < RHS) == (LHSVal < RHSVal));
+  assert((RHS < LHS) == (RHSVal < LHSVal));
+  assert((LHS > RHS) == (LHSVal > RHSVal));
+  assert((RHS > LHS) == (RHSVal > LHSVal));
+  assert((LHS <= RHS) == (LHSVal <= RHSVal));
+  assert((RHS <= LHS) == (RHSVal <= LHSVal));
+  assert((LHS >= RHS) == (LHSVal >= RHSVal));
+  assert((RHS >= LHS) == (RHSVal >= LHSVal));
+  {
+    static_assert(noexcept(LHS < RHS), "");
+    static_assert(noexcept(LHS > RHS), "");
+    static_assert(noexcept(LHS <= RHS), "");
+    static_assert(noexcept(LHS >= RHS), "");
+    ASSERT_SAME_TYPE(decltype(LHS < RHS), bool);
+    ASSERT_SAME_TYPE(decltype(LHS > RHS), bool);
+    ASSERT_SAME_TYPE(decltype(LHS <= RHS), bool);
+    ASSERT_SAME_TYPE(decltype(LHS >= RHS), bool);
+  }
+}
+
+int main(int, char**)
+{
+  int i;
+  std::pair<int *, int *> const TestCases[] = {
+      {nullptr, nullptr},
+      {&i, &i},
+      {nullptr, &i},
+      {&i, nullptr}
+  };
+  for (auto& TC : TestCases) {
+    do_test<std::coroutine_handle<>>(TC.first, TC.second);
+    do_test<std::coroutine_handle<int>>(TC.first, TC.second);
+  }
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.handle/coroutine.handle.completion/done.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <coroutine>
+
+// template <class Promise = void>
+// struct coroutine_handle;
+
+// bool done() const
+
+#include <coroutine>
+#include <type_traits>
+#include <memory>
+#include <utility>
+#include <cstdint>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class Promise>
+void do_test(std::coroutine_handle<Promise> const& H) {
+  // FIXME Add a runtime test
+  {
+    ASSERT_SAME_TYPE(decltype(H.done()), bool);
+    LIBCPP_ASSERT_NOT_NOEXCEPT(H.done());
+  }
+}
+
+int main(int, char**)
+{
+  do_test(std::coroutine_handle<>{});
+  do_test(std::coroutine_handle<int>{});
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.handle/coroutine.handle.con/assign.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <coroutine>
+
+// template <class Promise = void>
+// struct coroutine_handle;
+
+// coroutine_handle& operator=(nullptr_t) noexcept
+
+#include <coroutine>
+#include <type_traits>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class C>
+void do_test() {
+  int dummy = 42;
+  void* dummy_h = &dummy;
+  {
+    static_assert(std::is_nothrow_assignable<C&, std::nullptr_t>::value, "");
+    static_assert(!std::is_assignable<C&, void*>::value, "");
+  }
+  {
+    C c = C::from_address(dummy_h);
+    assert(c.address() == &dummy);
+    c = nullptr;
+    assert(c.address() == nullptr);
+    c = nullptr;
+    assert(c.address() == nullptr);
+  }
+  {
+    C c;
+    C& cr = (c = nullptr);
+    assert(&c == &cr);
+  }
+}
+
+int main(int, char**)
+{
+  do_test<std::coroutine_handle<>>();
+  do_test<std::coroutine_handle<int>>();
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.handle/coroutine.handle.con/construct.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <coroutine>
+
+// template <class Promise = void>
+// struct coroutine_handle;
+
+// constexpr coroutine_handle() noexcept
+// constexpr coroutine_handle(nullptr_t) noexcept
+
+#include <coroutine>
+#include <type_traits>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class C>
+constexpr bool do_test() {
+  static_assert(std::is_nothrow_constructible<C>::value, "");
+  static_assert(std::is_nothrow_constructible<C, std::nullptr_t>::value, "");
+  {
+    C c;
+    assert(c.address() == nullptr);
+  }
+  {
+    C c = C(nullptr);
+    assert(c.address() == nullptr);
+  }
+  return true;
+}
+
+int main(int, char**)
+{
+  do_test<std::coroutine_handle<>>();
+  do_test<std::coroutine_handle<int>>();
+  static_assert(do_test<std::coroutine_handle<>>());
+  static_assert(do_test<std::coroutine_handle<int>>());
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/address.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <coroutine>
+
+// template <class Promise = void>
+// struct coroutine_handle;
+
+// constexpr void* address() const noexcept
+
+#include <coroutine>
+#include <type_traits>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class C>
+constexpr bool do_test() {
+  {
+    constexpr C c; ((void)c);
+    static_assert(c.address() == nullptr, "");
+  }
+  {
+    const C c = {}; ((void)c);
+    ASSERT_NOEXCEPT(c.address());
+    ASSERT_SAME_TYPE(decltype(c.address()), void*);
+    assert(c.address() == nullptr);
+  }
+  {
+    char dummy = 42;
+    C c = C::from_address((void*)&dummy);
+    assert(c.address() == &dummy);
+  }
+  return true;
+}
+
+int main(int, char**)
+{
+  do_test<std::coroutine_handle<>>();
+  do_test<std::coroutine_handle<int>>();
+  static_assert(do_test<std::coroutine_handle<>>());
+  static_assert(do_test<std::coroutine_handle<int>>());
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.handle/coroutine.handle.export/from_address.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <coroutine>
+
+// template <class Promise = void>
+// struct coroutine_handle;
+
+// static coroutine_handle from_address(void*) noexcept
+
+#include <coroutine>
+#include <type_traits>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class C>
+void do_test() {
+  {
+    C c = C::from_address(nullptr);
+    static_assert(noexcept(C::from_address(nullptr)), "");
+    static_assert(std::is_same<decltype(C::from_address(nullptr)), C>::value, "");
+    assert(c.address() == nullptr);
+  }
+  {
+    char dummy = 42;
+    C c = C::from_address((void*)&dummy);
+    assert(c.address() == &dummy);
+  }
+  {
+    C::from_address((int*)nullptr);
+    C::from_address((void*)nullptr);
+    C::from_address((char*)nullptr);
+  }
+  {
+    char dummy = 42;
+    C c = C::from_address(&dummy);
+    int* p = (int*)c.address();
+    std::coroutine_handle<> c2 = std::coroutine_handle<>::from_address(p);
+    assert(c2 == c);
+  }
+}
+
+int main(int, char**)
+{
+  do_test<std::coroutine_handle<>>();
+  do_test<std::coroutine_handle<int>>();
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.handle/coroutine.handle.noop/noop_coroutine.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: ubsan
+
+// <coroutine>
+// struct noop_coroutine_promise;
+// using noop_coroutine_handle = coroutine_handle<noop_coroutine_promise>;
+// noop_coroutine_handle noop_coroutine() noexcept;
+
+#include <coroutine>
+#include <cassert>
+#include <type_traits>
+
+#include "test_macros.h"
+
+#if __has_builtin(__builtin_coro_noop)
+
+static_assert(std::is_same<std::coroutine_handle<std::noop_coroutine_promise>, std::noop_coroutine_handle>::value, "");
+static_assert(std::is_same<decltype(std::noop_coroutine()), std::noop_coroutine_handle>::value, "");
+
+// template <> struct coroutine_handle<noop_coroutine_promise> : coroutine_handle<>
+// {
+// // [coroutine.handle.noop.observers], observers
+// constexpr explicit operator bool() const noexcept;
+// constexpr bool done() const noexcept;
+
+// // [coroutine.handle.noop.resumption], resumption
+// constexpr void operator()() const noexcept;
+// constexpr void resume() const noexcept;
+// constexpr void destroy() const noexcept;
+
+// // [coroutine.handle.noop.promise], promise access
+// noop_coroutine_promise& promise() const noexcept;
+
+// // [coroutine.handle.noop.address], address
+// constexpr void* address() const noexcept;
+
+int main(int, char**)
+{
+  auto h = std::noop_coroutine();
+  std::coroutine_handle<> base = h;
+
+  assert(h);
+  assert(base);
+
+  assert(!h.done());
+  assert(!base.done());
+
+  h.resume();
+  h.destroy();
+  h();
+  static_assert(h.done() == false, "");
+  static_assert(h, "");
+
+  h.promise();
+  assert(h.address() == base.address());
+  assert(h==base);
+  assert(h.address() != nullptr);
+  assert(std::coroutine_handle<>::from_address(h.address()) == base);
+
+  return 0;
+}
+
+#else
+
+int main(int, char**) { return 0; }
+
+#endif //  __has_builtin(__builtin_coro_noop)

libcxx/test/std/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <coroutine>
+
+// template <class Promise>
+// struct coroutine_handle<Promise>;
+
+// Promise& promise() const
+
+#include <coroutine>
+#include <type_traits>
+#include <memory>
+#include <utility>
+#include <cstdint>
+#include <cassert>
+
+#include "test_macros.h"
+
+struct MyCoro {
+  struct promise_type {
+    void unhandled_exception() {}
+    void return_void() {}
+    std::suspend_never initial_suspend() { return {}; }
+    std::suspend_never final_suspend() noexcept { return {}; }
+    MyCoro get_return_object() {
+      do_runtime_test();
+      return {};
+    }
+    void do_runtime_test() {
+      // Test that a coroutine_handle<const T> can be created from a const
+      // promise_type and that it represents the same coroutine as
+      // coroutine_handle<T>
+      using CH = std::coroutine_handle<promise_type>;
+      using CCH = std::coroutine_handle<const promise_type>;
+      const auto &cthis = *this;
+      CH h = CH::from_promise(*this);
+      CCH h2 = CCH::from_promise(*this);
+      CCH h3 = CCH::from_promise(cthis);
+      assert(&h.promise() == this);
+      assert(&h2.promise() == this);
+      assert(&h3.promise() == this);
+      assert(h.address() == h2.address());
+      assert(h2.address() == h3.address());
+    }
+  };
+};
+
+MyCoro do_runtime_test() {
+  co_await std::suspend_never{};
+}
+
+template <class Promise>
+void do_test(std::coroutine_handle<Promise>&& H) {
+
+  // FIXME Add a runtime test
+  {
+    ASSERT_SAME_TYPE(decltype(H.promise()), Promise&);
+    LIBCPP_ASSERT_NOT_NOEXCEPT(H.promise());
+  }
+  {
+    auto const& CH = H;
+    ASSERT_SAME_TYPE(decltype(CH.promise()), Promise&);
+    LIBCPP_ASSERT_NOT_NOEXCEPT(CH.promise());
+  }
+}
+
+int main(int, char**)
+{
+  do_test(std::coroutine_handle<int>{});
+  do_test(std::coroutine_handle<const int>{});
+  do_runtime_test();
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.handle/coroutine.handle.resumption/destroy.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <coroutine>
+
+// template <class Promise = void>
+// struct coroutine_handle;
+
+// void destroy() const
+
+#include <coroutine>
+#include <type_traits>
+#include <memory>
+#include <utility>
+#include <cstdint>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class H>
+auto has_destroy_imp(H&& h, int) -> decltype(h.destroy(), std::true_type{});
+template <class H>
+auto has_destroy_imp(H&&, long) -> std::false_type;
+
+template <class H>
+constexpr bool has_destroy() {
+  return decltype(has_destroy_imp(std::declval<H>(), 0))::value;
+}
+
+template <class Promise>
+void do_test(std::coroutine_handle<Promise>&& H) {
+  using HType = std::coroutine_handle<Promise>;
+  // FIXME Add a runtime test
+  {
+    ASSERT_SAME_TYPE(decltype(H.destroy()), void);
+    LIBCPP_ASSERT_NOT_NOEXCEPT(H.destroy());
+    static_assert(has_destroy<HType&>(), "");
+    static_assert(has_destroy<HType&&>(), "");
+  }
+  {
+    static_assert(has_destroy<HType const&>(), "");
+    static_assert(has_destroy<HType const&&>(), "");
+  }
+}
+
+int main(int, char**)
+{
+  do_test(std::coroutine_handle<>{});
+  do_test(std::coroutine_handle<int>{});
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.handle/coroutine.handle.resumption/resume.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <coroutine>
+
+// template <class Promise = void>
+// struct coroutine_handle;
+
+// void operator()() const
+// void resume() const
+
+#include <coroutine>
+#include <type_traits>
+#include <memory>
+#include <utility>
+#include <cstdint>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class H>
+auto has_resume_imp(H&& h, int) -> decltype(h.resume(), std::true_type{});
+template <class H>
+auto has_resume_imp(H&&, long) -> std::false_type;
+
+template <class H>
+constexpr bool has_resume() {
+  return decltype(has_resume_imp(std::declval<H>(), 0))::value;
+}
+
+
+template <class H>
+auto has_call_operator_imp(H&& h, int) -> decltype(h(), std::true_type{});
+template <class H>
+auto has_call_operator_imp(H&&, long) -> std::false_type;
+
+template <class H>
+constexpr bool has_call_operator() {
+  return decltype(has_call_operator_imp(std::declval<H>(), 0))::value;
+}
+
+template <class Promise>
+void do_test(std::coroutine_handle<Promise>&& H) {
+  using HType = std::coroutine_handle<Promise>;
+  // FIXME Add a runtime test
+  {
+    ASSERT_SAME_TYPE(decltype(H.resume()), void);
+    ASSERT_SAME_TYPE(decltype(H()), void);
+    LIBCPP_ASSERT_NOT_NOEXCEPT(H.resume());
+    LIBCPP_ASSERT_NOT_NOEXCEPT(H());
+    static_assert(has_resume<HType&>(), "");
+    static_assert(has_resume<HType&&>(), "");
+    static_assert(has_call_operator<HType&>(), "");
+    static_assert(has_call_operator<HType&&>(), "");
+  }
+  {
+    static_assert(has_resume<HType const&>(), "");
+    static_assert(has_resume<HType const&&>(), "");
+    static_assert(has_call_operator<HType const&>(), "");
+    static_assert(has_call_operator<HType const&&>(), "");
+  }
+}
+
+int main(int, char**)
+{
+  do_test(std::coroutine_handle<>{});
+  do_test(std::coroutine_handle<int>{});
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.handle/void_handle.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+#include <coroutine>
+
+#include "test_macros.h"
+
+struct A {
+  using promise_type = A*;
+};
+
+struct B {};
+struct C {};
+
+template <>
+struct std::coroutine_traits<A, int> {
+  using promise_type = int*;
+};
+template <class ...Args>
+struct std::coroutine_traits<B, Args...> {
+  using promise_type = B*;
+};
+template <>
+struct std::coroutine_traits<C> {
+  using promise_type = void;
+};
+
+template <class Expect, class T, class ...Args>
+void check_type() {
+  using P = typename std::coroutine_traits<T, Args...>::promise_type ;
+  static_assert(std::is_same<P, Expect>::value, "");
+};
+
+int main(int, char**)
+{
+  check_type<A*, A>();
+  check_type<int*, A, int>();
+  check_type<B*, B>();
+  check_type<void, C>();
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.traits/promise_type.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+#include <coroutine>
+
+#include "test_macros.h"
+
+template <class T, class = typename T::promise_type>
+constexpr bool has_promise_type(int) { return true; }
+template <class>
+constexpr bool has_promise_type(long) { return false; }
+template <class T>
+constexpr bool has_promise_type() { return has_promise_type<T>(0); }
+
+struct A {
+  using promise_type = A*;
+};
+
+struct B {};
+struct C {};
+struct D {
+private:
+  using promise_type = void;
+};
+struct E {};
+
+template <>
+struct std::coroutine_traits<A, int> {
+  using promise_type = int*;
+};
+template <class ...Args>
+struct std::coroutine_traits<B, Args...> {
+  using promise_type = B*;
+};
+template <>
+struct std::coroutine_traits<C> {
+  using promise_type = void;
+};
+
+template <class Expect, class T, class ...Args>
+void check_type() {
+  using Traits = std::coroutine_traits<T, Args...>;
+  static_assert(has_promise_type<Traits>(), "");
+  static_assert(std::is_same<typename Traits::promise_type, Expect>::value, "");
+}
+
+template <class T, class ...Args>
+void check_no_type() {
+  using Traits = std::coroutine_traits<T, Args...>;
+  static_assert(!has_promise_type<Traits>(), "");
+}
+
+int main(int, char**)
+{
+  {
+    check_type<A*, A>();
+    check_type<int*, A, int>();
+    check_type<B*, B>();
+    check_type<void, C>();
+  }
+  {
+    check_no_type<D>();
+    check_no_type<E>();
+    check_no_type<C, int>();
+  }
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.trivial.awaitables/suspend_always.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+#include <coroutine>
+#include <type_traits>
+#include <cassert>
+
+#include "test_macros.h"
+
+TEST_SAFE_STATIC std::suspend_always safe_sa;
+
+constexpr bool check_suspend_constexpr() {
+  std::suspend_always s{};
+  const std::suspend_always scopy(s);
+  std::suspend_always smove(std::move(s));
+  s = scopy;
+  s = std::move(smove);
+  return true;
+}
+
+template<class T>
+constexpr bool test_trivial_awaitable_constexpr(bool expected) {
+  T t;
+  assert(t.await_ready() == expected);
+  t.await_suspend(nullptr);
+  t.await_resume();
+  return true;
+}
+
+int main(int, char**)
+{
+  std::coroutine_handle<> h{};
+  std::suspend_always s{};
+  std::suspend_always const& cs = s;
+  {
+    ASSERT_NOEXCEPT(s.await_ready());
+    static_assert(std::is_same<decltype(s.await_ready()), bool>::value, "");
+    assert(s.await_ready() == false);
+    assert(cs.await_ready() == false);
+  }
+  {
+    ASSERT_NOEXCEPT(s.await_suspend(h));
+    static_assert(std::is_same<decltype(s.await_suspend(h)), void>::value, "");
+    s.await_suspend(h);
+    cs.await_suspend(h);
+  }
+  {
+    ASSERT_NOEXCEPT(s.await_resume());
+    static_assert(std::is_same<decltype(s.await_resume()), void>::value, "");
+    s.await_resume();
+    cs.await_resume();
+  }
+  {
+    static_assert(std::is_nothrow_default_constructible<std::suspend_always>::value, "");
+    static_assert(std::is_nothrow_copy_constructible<std::suspend_always>::value, "");
+    static_assert(std::is_nothrow_move_constructible<std::suspend_always>::value, "");
+    static_assert(std::is_nothrow_copy_assignable<std::suspend_always>::value, "");
+    static_assert(std::is_nothrow_move_assignable<std::suspend_always>::value, "");
+    static_assert(std::is_trivially_copyable<std::suspend_always>::value, "");
+    static_assert(check_suspend_constexpr(), "");
+  }
+  {
+    static_assert(test_trivial_awaitable_constexpr<std::suspend_always>(false));
+  }
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/coroutine.trivial.awaitables/suspend_never.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+#include <coroutine>
+#include <type_traits>
+#include <cassert>
+
+#include "test_macros.h"
+
+// Test that the type 'std::suspend_never' is in the correct namespace
+
+TEST_SAFE_STATIC std::suspend_never safe_sn;
+constexpr std::suspend_never constexpr_sn;
+
+constexpr bool check_suspend_constexpr() {
+  std::suspend_never s{};
+  const std::suspend_never scopy(s); ((void)scopy);
+  std::suspend_never smove(std::move(s)); ((void)smove);
+  s = scopy;
+  s = std::move(smove);
+  return true;
+}
+
+template<class T>
+constexpr bool test_trivial_awaitable_constexpr(bool expected) {
+  T t;
+  assert(t.await_ready() == expected);
+  t.await_suspend(nullptr);
+  t.await_resume();
+  return true;
+}
+
+int main(int, char**)
+{
+  using H = std::coroutine_handle<>;
+  using S = std::suspend_never;
+  H h{};
+  S s{};
+  S const& cs = s;
+  {
+    LIBCPP_STATIC_ASSERT(noexcept(s.await_ready()), "");
+    static_assert(std::is_same<decltype(s.await_ready()), bool>::value, "");
+    assert(s.await_ready() == true);
+    assert(cs.await_ready() == true);
+  }
+  {
+    LIBCPP_STATIC_ASSERT(noexcept(s.await_suspend(h)), "");
+    static_assert(std::is_same<decltype(s.await_suspend(h)), void>::value, "");
+    s.await_suspend(h);
+    cs.await_suspend(h);
+  }
+  {
+    LIBCPP_STATIC_ASSERT(noexcept(s.await_resume()), "");
+    static_assert(std::is_same<decltype(s.await_resume()), void>::value, "");
+    s.await_resume();
+    cs.await_resume();
+  }
+  {
+    static_assert(std::is_nothrow_default_constructible<std::suspend_never>::value, "");
+    static_assert(std::is_nothrow_copy_constructible<std::suspend_never>::value, "");
+    static_assert(std::is_nothrow_move_constructible<std::suspend_never>::value, "");
+    static_assert(std::is_nothrow_copy_assignable<std::suspend_never>::value, "");
+    static_assert(std::is_nothrow_move_assignable<std::suspend_never>::value, "");
+    static_assert(std::is_trivially_copyable<std::suspend_never>::value, "");
+    static_assert(check_suspend_constexpr(), "");
+  }
+  {
+    static_assert(test_trivial_awaitable_constexpr<std::suspend_never>(true));
+  }
+  {
+    // suppress unused warnings for the global constexpr test variable
+    ((void)constexpr_sn);
+  }
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/end.to.end/await_result.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+#include <coroutine>
+#include <cassert>
+
+#include "test_macros.h"
+
+struct coro_t {
+  struct promise_type {
+    coro_t get_return_object() {
+      std::coroutine_handle<promise_type>{};
+      return {};
+    }
+    std::suspend_never initial_suspend() { return {}; }
+    std::suspend_never final_suspend() noexcept { return {}; }
+    void return_void() {}
+    static void unhandled_exception() {}
+  };
+};
+
+struct B {
+  ~B() {}
+  bool await_ready() { return true; }
+  B await_resume() { return {}; }
+  template <typename F> void await_suspend(F) {}
+};
+
+
+struct A {
+  ~A() {}
+  bool await_ready() { return true; }
+  int await_resume() { return 42; }
+  template <typename F> void await_suspend(F) {}
+};
+
+int last_value = -1;
+void set_value(int x) {
+  last_value = x;
+}
+
+coro_t f(int n) {
+  if (n == 0) {
+    set_value(0);
+    co_return;
+  }
+  int val = co_await A{};
+  ((void)val);
+  set_value(42);
+}
+
+coro_t g() { B val = co_await B{}; }
+
+int main(int, char**) {
+  last_value = -1;
+  f(0);
+  assert(last_value == 0);
+  f(1);
+  assert(last_value == 42);
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/end.to.end/bool_await_suspend.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// See https://llvm.org/PR33271
+// UNSUPPORTED: ubsan
+
+#include <coroutine>
+#include <cassert>
+
+#include "test_macros.h"
+
+struct coro_t {
+  struct promise_type {
+    coro_t get_return_object() {
+      return std::coroutine_handle<promise_type>::from_promise(*this);
+    }
+    std::suspend_never initial_suspend() { return {}; }
+    std::suspend_never final_suspend() noexcept { return {}; }
+    void return_void() {}
+    void unhandled_exception() {}
+  };
+  coro_t(std::coroutine_handle<promise_type> hh) : h(hh) {}
+  std::coroutine_handle<promise_type> h;
+};
+
+struct NoSuspend {
+  bool await_ready() { return false; }
+  void await_resume() {}
+  template <typename F> bool await_suspend(F) { return false; }
+};
+
+struct DoSuspend {
+  bool await_ready() { return false; }
+  void await_resume() {}
+  template <typename F> bool await_suspend(F) { return true; }
+};
+
+bool f_started, f_resumed = false;
+coro_t f() {
+  f_started = true;
+  co_await DoSuspend{};
+  f_resumed = true;
+}
+
+bool g_started, g_resumed = false;
+coro_t g() {
+  g_started = true;
+  co_await NoSuspend{};
+  g_resumed = true;
+}
+
+int main(int, char**) {
+  assert(!f_started && !f_resumed && !g_started && !g_resumed);
+  auto fret = f();
+  assert(f_started && !f_resumed);
+  fret.h.destroy();
+  assert(f_started && !f_resumed);
+  g();
+  assert(g_started && g_resumed);
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/end.to.end/expected.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+#include <coroutine>
+#include <cassert>
+#include <memory>
+
+#include "test_macros.h"
+
+struct error_tag { };
+
+template <typename T, typename Error = int>
+struct expected {
+
+  struct Data {
+    Data() : val(), error() { }
+    Data(T v, Error e) : val(v), error(e) { }
+    T val;
+    Error error;
+  };
+  std::shared_ptr<Data> data;
+
+  expected(T val) : data(std::make_shared<Data>(val, Error())) {}
+  expected(error_tag, Error error) : data(std::make_shared<Data>(T(), error)) {}
+  expected(std::shared_ptr<Data> p) : data(p) {}
+
+  struct promise_type {
+    std::shared_ptr<Data> data;
+    expected get_return_object() { data = std::make_shared<Data>(); return {data}; }
+    std::suspend_never initial_suspend() { return {}; }
+    std::suspend_never final_suspend() noexcept { return {}; }
+    void return_value(T v) { data->val = v; data->error = {}; }
+    void unhandled_exception() {}
+  };
+
+  bool await_ready() { return !data->error; }
+  T await_resume() { return data->val; }
+  void await_suspend(std::coroutine_handle<promise_type> h) {
+    h.promise().data->error = data->error;
+    h.destroy();
+  }
+
+  T const& value() { return data->val; }
+  Error const& error() { return data->error; }
+};
+
+expected<int> g() { return {0}; }
+expected<int> h() { return {error_tag{}, 42}; }
+
+extern "C" void print(int);
+
+bool f1_started, f1_resumed = false;
+expected<int> f1() {
+  f1_started = true;
+  (void)(co_await g());
+  f1_resumed = true;
+  co_return 100;
+}
+
+bool f2_started, f2_resumed = false;
+expected<int> f2() {
+  f2_started = true;
+  (void)(co_await h());
+  f2_resumed = true;
+  co_return 200;
+}
+
+int main(int, char**) {
+  auto c1 = f1();
+  assert(f1_started && f1_resumed);
+  assert(c1.value() == 100);
+  assert(c1.error() == 0);
+
+  auto c2 = f2();
+  assert(f2_started && !f2_resumed);
+  assert(c2.value() == 0);
+  assert(c2.error() == 42);
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/end.to.end/fullexpr-dtor.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+#include <coroutine>
+#include <cassert>
+
+#include "test_macros.h"
+
+int alive = 0;
+int ctor_called = 0;
+int dtor_called = 0;
+void reset() {
+  assert(alive == 0);
+  alive = 0;
+  ctor_called = 0;
+  dtor_called = 0;
+}
+struct Noisy {
+  Noisy() { ++alive; ++ctor_called; }
+  ~Noisy() { --alive; ++dtor_called; }
+  Noisy(Noisy const&) = delete;
+};
+
+struct Bug {
+  bool await_ready() { return true; }
+  void await_suspend(std::coroutine_handle<>) {}
+  Noisy await_resume() { return {}; }
+};
+struct coro2 {
+  struct promise_type {
+    std::suspend_never initial_suspend() { return {}; }
+    std::suspend_never final_suspend() noexcept { return {}; }
+    coro2 get_return_object() { return {}; }
+    void return_void() {}
+    Bug yield_value(int) { return {}; }
+    void unhandled_exception() {}
+  };
+};
+
+// Checks that destructors are correctly invoked for the object returned by
+// coawait.
+coro2 a() {
+  reset();
+  {
+    auto x = co_await Bug{};
+    assert(alive == 1);
+    assert(ctor_called == 1);
+    assert(dtor_called == 0);
+    ((void)x);
+  }
+  assert(alive == 0);
+  assert(dtor_called == 1);
+}
+
+coro2 b() {
+  reset();
+  {
+    co_await Bug{};
+    assert(ctor_called == 1);
+    assert(dtor_called == 1);
+    assert(alive == 0);
+  }
+  assert(ctor_called == 1);
+  assert(dtor_called == 1);
+  assert(alive == 0);
+
+}
+
+coro2 c() {
+  reset();
+  {
+    auto x = co_yield 42;
+    assert(alive == 1);
+    assert(ctor_called == 1);
+    assert(dtor_called == 0);
+  }
+  assert(alive == 0);
+  assert(ctor_called == 1);
+  assert(dtor_called == 1);
+}
+
+coro2 d() {
+  reset();
+  {
+    co_yield 42;
+    assert(ctor_called == 1);
+    assert(dtor_called == 1);
+    assert(alive == 0);
+  }
+  assert(alive == 0);
+  assert(ctor_called == 1);
+  assert(dtor_called == 1);
+}
+
+int main(int, char**) {
+  a();
+  b();
+  c();
+  d();
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/end.to.end/generator.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// See https://llvm.org/PR33271
+// UNSUPPORTED: ubsan
+
+#include <coroutine>
+#include <vector>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <typename Ty> struct generator {
+  struct promise_type {
+    Ty current_value;
+    std::suspend_always yield_value(Ty value) {
+      this->current_value = value;
+      return {};
+    }
+    std::suspend_always initial_suspend() { return {}; }
+    std::suspend_always final_suspend() noexcept { return {}; }
+    generator get_return_object() { return generator{this}; };
+    void return_void() {}
+    void unhandled_exception() {}
+  };
+
+  struct iterator {
+    std::coroutine_handle<promise_type> Coro_;
+    bool Done_;
+
+    iterator(std::coroutine_handle<promise_type> Coro, bool Done)
+        : Coro_(Coro), Done_(Done) {}
+
+    iterator &operator++() {
+      Coro_.resume();
+      Done_ = Coro_.done();
+      return *this;
+    }
+
+    bool operator==(iterator const &_Right) const {
+      return Done_ == _Right.Done_;
+    }
+
+    bool operator!=(iterator const &_Right) const { return !(*this == _Right); }
+
+    Ty const &operator*() const { return Coro_.promise().current_value; }
+
+    Ty const *operator->() const { return &(operator*()); }
+  };
+
+  iterator begin() {
+    p.resume();
+    return {p, p.done()};
+  }
+
+  iterator end() { return {p, true}; }
+
+  generator(generator &&rhs) : p(rhs.p) { rhs.p = nullptr; }
+
+  ~generator() {
+    if (p)
+      p.destroy();
+  }
+
+private:
+  explicit generator(promise_type *promise)
+      : p(std::coroutine_handle<promise_type>::from_promise(*promise)) {}
+
+  std::coroutine_handle<promise_type> p;
+};
+
+struct minig {
+  struct promise_type {
+    int current_value;
+    std::suspend_always yield_value(int value) {
+      this->current_value = value;
+      return {};
+    }
+    std::suspend_always initial_suspend() { return {}; }
+    std::suspend_always final_suspend() noexcept { return {}; }
+    minig get_return_object() { return minig{this}; };
+    void return_void() {}
+    void unhandled_exception() {}
+  };
+
+  bool move_next() {
+    p.resume();
+    return !p.done();
+  }
+  int current_value() { return p.promise().current_value; }
+
+  minig(minig &&rhs) : p(rhs.p) { rhs.p = nullptr; }
+
+  ~minig() {
+    if (p)
+      p.destroy();
+  }
+
+private:
+  explicit minig(promise_type *promise)
+      : p(std::coroutine_handle<promise_type>::from_promise(*promise)) {}
+
+  std::coroutine_handle<promise_type> p;
+};
+
+
+minig mini_count(int n) {
+  for (int i = 0; i < n; i++) {
+    co_yield i;
+  }
+}
+
+generator<int> count(int n) {
+  for (int i = 0; i < n; ++i)
+    co_yield i;
+}
+
+generator<int> range(int from, int n) {
+  for (int i = from; i < n; ++i)
+    co_yield i;
+}
+
+void test_count() {
+  const std::vector<int> expect = {0, 1, 2, 3, 4};
+  std::vector<int> got;
+  for (auto x : count(5))
+    got.push_back(x);
+  assert(expect == got);
+}
+
+void test_range() {
+  int sum = 0;
+   for (auto v: range(1, 20))
+      sum += v;
+   assert(sum == 190);
+}
+
+void test_mini_generator() {
+  int sum = 0;
+  auto g = mini_count(5);
+  while (g.move_next()) {
+     sum += g.current_value();
+  }
+  assert(sum == 10);
+}
+
+int main(int, char**) {
+  test_count();
+  test_range();
+  test_mini_generator();
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/end.to.end/go.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+#include <cassert>
+#include <coroutine>
+#include <memory>
+
+#include "test_macros.h"
+
+bool cancel = false;
+
+struct goroutine
+{
+  static int const N = 10;
+  static int count;
+  static std::coroutine_handle<> stack[N];
+
+  static void schedule(std::coroutine_handle<>& rh)
+  {
+    assert(count < N);
+    stack[count++] = rh;
+    rh = nullptr;
+  }
+
+  ~goroutine() {}
+
+  static void go(goroutine) {}
+
+  static void run_one()
+  {
+    assert(count > 0);
+    stack[--count]();
+  }
+
+  struct promise_type
+  {
+    std::suspend_never initial_suspend() {
+      return {};
+    }
+    std::suspend_never final_suspend() noexcept { return {}; }
+    void return_void() {}
+    goroutine get_return_object() {
+      return{};
+    }
+    void unhandled_exception() {}
+  };
+};
+int goroutine::count;
+std::coroutine_handle<> goroutine::stack[N];
+
+std::coroutine_handle<goroutine::promise_type> workaround;
+
+class channel;
+
+struct push_awaiter {
+  channel* ch;
+  bool await_ready() {return false; }
+  void await_suspend(std::coroutine_handle<> rh);
+  void await_resume() {}
+};
+
+struct pull_awaiter {
+  channel * ch;
+
+  bool await_ready();
+  void await_suspend(std::coroutine_handle<> rh);
+  int await_resume();
+};
+
+class channel
+{
+  using T = int;
+
+  friend struct push_awaiter;
+  friend struct pull_awaiter;
+
+  T const* pvalue = nullptr;
+  std::coroutine_handle<> reader = nullptr;
+  std::coroutine_handle<> writer = nullptr;
+public:
+  push_awaiter push(T const& value)
+  {
+    assert(pvalue == nullptr);
+    assert(!writer);
+    pvalue = &value;
+
+    return { this };
+  }
+
+  pull_awaiter pull()
+  {
+    assert(!reader);
+
+    return { this };
+  }
+
+  void sync_push(T const& value)
+  {
+    assert(!pvalue);
+    pvalue = &value;
+    assert(reader);
+    reader();
+    assert(!pvalue);
+    reader = nullptr;
+  }
+
+  auto sync_pull()
+  {
+    while (!pvalue) goroutine::run_one();
+    auto result = *pvalue;
+    pvalue = nullptr;
+    if (writer)
+    {
+      auto wr = writer;
+      writer = nullptr;
+      wr();
+    }
+    return result;
+  }
+};
+
+void push_awaiter::await_suspend(std::coroutine_handle<> rh)
+{
+  ch->writer = rh;
+  if (ch->reader) goroutine::schedule(ch->reader);
+}
+
+
+bool pull_awaiter::await_ready() {
+  return !!ch->writer;
+}
+void pull_awaiter::await_suspend(std::coroutine_handle<> rh) {
+  ch->reader = rh;
+}
+int pull_awaiter::await_resume() {
+  auto result = *ch->pvalue;
+  ch->pvalue = nullptr;
+  if (ch->writer) {
+    //goroutine::schedule(ch->writer);
+    auto wr = ch->writer;
+    ch->writer = nullptr;
+    wr();
+  }
+  return result;
+}
+
+goroutine pusher(channel& left, channel& right)
+{
+  for (;;) {
+    auto val = co_await left.pull();
+    co_await right.push(val + 1);
+  }
+}
+
+const int N = 100;
+auto c = std::make_unique<channel[]>(N + 1);
+
+int main(int, char**) {
+  for (int i = 0; i < N; ++i)
+    pusher(c[i], c[i + 1]);
+
+  c[0].sync_push(0);
+  int result = c[N].sync_pull();
+
+  assert(result == 100);
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/end.to.end/multishot_func.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+#include <coroutine>
+#include <cassert>
+
+#include "test_macros.h"
+
+// This file tests, multishot, movable std::function like thing using coroutine
+// for compile-time type erasure and unerasure.
+template <typename R> struct func {
+  struct Input {R a, b;};
+
+  struct promise_type {
+    Input* I;
+    R result;
+    func get_return_object() { return {this}; }
+    std::suspend_always initial_suspend() { return {}; }
+    std::suspend_never final_suspend() noexcept { return {}; }
+    void return_void() {}
+    template <typename F>
+    std::suspend_always yield_value(F&& f) {
+      result = f(I->a, I->b);
+      return {};
+    }
+    void unhandled_exception() {}
+  };
+
+  R operator()(Input I) {
+    h.promise().I = &I;
+    h.resume();
+    R result = h.promise().result;
+    return result;
+  };
+
+  func() {}
+  func(func &&rhs) : h(rhs.h) { rhs.h = nullptr; }
+  func(func const &) = delete;
+
+  func &operator=(func &&rhs) {
+    if (this != &rhs) {
+      if (h)
+        h.destroy();
+      h = rhs.h;
+      rhs.h = nullptr;
+    }
+    return *this;
+  }
+
+  template <typename F> static func Create(F f) {
+    for (;;) {
+      co_yield f;
+    }
+  }
+
+  template <typename F> func(F f) : func(Create(f)) {}
+
+  ~func() {
+    if (h)
+      h.destroy();
+  }
+
+private:
+  func(promise_type *promise)
+      : h(std::coroutine_handle<promise_type>::from_promise(*promise)) {}
+  std::coroutine_handle<promise_type> h;
+};
+
+int Do(int acc, int n, func<int> f) {
+  for (int i = 0; i < n; ++i)
+    acc = f({acc, i});
+  return acc;
+}
+
+int main(int, char**) {
+  int result = Do(1, 10, [](int a, int b) {return a + b;});
+  assert(result == 46);
+
+  return 0;
+}

libcxx/test/std/language.support/support.coroutines/end.to.end/oneshot_func.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+#include <coroutine>
+#include <vector>
+#include <cassert>
+
+#include "test_macros.h"
+
+// This file tests, one shot, movable std::function like thing using coroutine
+// for compile-time type erasure and unerasure.
+
+template <typename R> struct func {
+  struct promise_type {
+    R result;
+    func get_return_object() { return {this}; }
+    std::suspend_always initial_suspend() { return {}; }
+    std::suspend_always final_suspend() noexcept { return {}; }
+    void return_value(R v) { result = v; }
+    void unhandled_exception() {}
+  };
+
+  R operator()() {
+    h.resume();
+    R result = h.promise().result;
+    h.destroy();
+    h = nullptr;
+    return result;
+  };
+
+  func() {}
+  func(func &&rhs) : h(rhs.h) { rhs.h = nullptr; }
+  func(func const &) = delete;
+
+  func &operator=(func &&rhs) {
+    if (this != &rhs) {
+      if (h)
+        h.destroy();
+      h = rhs.h;
+      rhs.h = nullptr;
+    }
+    return *this;
+  }
+
+  template <typename F> static func Create(F f) { co_return f(); }
+
+  template <typename F> func(F f) : func(Create(f)) {}
+
+  ~func() {
+    if (h)
+      h.destroy();
+  }
+
+private:
+  func(promise_type *promise)
+      : h(std::coroutine_handle<promise_type>::from_promise(*promise)) {}
+  std::coroutine_handle<promise_type> h;
+};
+
+int main(int, char**) {
+  func<int> f = func<int>::Create([]() { return 44; });
+  assert(f() == 44);
+
+  return 0;
+}

libcxx/test/std/language.support/support.limits/support.limits.general/coroutine.version.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// WARNING: This test was generated by generate_feature_test_macro_components.py
+// and should not be edited manually.
+//
+// clang-format off
+
+// <coroutine>
+
+// Test the feature test macros defined by <coroutine>
+
+/*  Constant               Value
+    __cpp_lib_coroutine    201902L [C++20]
+*/
+
+#include <coroutine>
+#include "test_macros.h"
+
+#if TEST_STD_VER < 14
+
+# ifdef __cpp_lib_coroutine
+#   error "__cpp_lib_coroutine should not be defined before c++20"
+# endif
+
+#elif TEST_STD_VER == 14
+
+# ifdef __cpp_lib_coroutine
+#   error "__cpp_lib_coroutine should not be defined before c++20"
+# endif
+
+#elif TEST_STD_VER == 17
+
+# ifdef __cpp_lib_coroutine
+#   error "__cpp_lib_coroutine should not be defined before c++20"
+# endif
+
+#elif TEST_STD_VER == 20
+
+# ifndef __cpp_lib_coroutine
+#   error "__cpp_lib_coroutine should be defined in c++20"
+# endif
+# if __cpp_lib_coroutine != 201902L
+#   error "__cpp_lib_coroutine should have the value 201902L in c++20"
+# endif
+
+#elif TEST_STD_VER > 20
+
+# ifndef __cpp_lib_coroutine
+#   error "__cpp_lib_coroutine should be defined in c++2b"
+# endif
+# if __cpp_lib_coroutine != 201902L
+#   error "__cpp_lib_coroutine should have the value 201902L in c++2b"
+# endif
+
+#endif // TEST_STD_VER > 20
+
+int main(int, char**) { return 0; }

libcxx/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp

 #     error "__cpp_lib_constexpr_vector should have the value 201907L in c++20"
 #   endif
 # else // _LIBCPP_VERSION
 #   ifdef __cpp_lib_constexpr_vector
 #     error "__cpp_lib_constexpr_vector should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
-# if !defined(_LIBCPP_VERSION)
-#   ifndef __cpp_lib_coroutine
-#     error "__cpp_lib_coroutine should be defined in c++20"
-#   endif
-#   if __cpp_lib_coroutine != 201902L
-#     error "__cpp_lib_coroutine should have the value 201902L in c++20"
-#   endif
-# else // _LIBCPP_VERSION
-#   ifdef __cpp_lib_coroutine
-#     error "__cpp_lib_coroutine should not be defined because it is unimplemented in libc++!"
-#   endif
-# endif
+# ifndef __cpp_lib_coroutine
+#   error "__cpp_lib_coroutine should be defined in c++20"
+# endif
+# if __cpp_lib_coroutine != 201902L
+#   error "__cpp_lib_coroutine should have the value 201902L in c++20"
+# endif
 
 # if TEST_STD_VER > 17 && defined(__cpp_impl_destroying_delete) && __cpp_impl_destroying_delete >= 201806L
 #   ifndef __cpp_lib_destroying_delete
 #     error "__cpp_lib_destroying_delete should be defined in c++20"
 #   endif
 #   if __cpp_lib_destroying_delete != 201806L
 #     error "__cpp_lib_destroying_delete should have the value 201806L in c++20"
 #   endif

 #     error "__cpp_lib_constexpr_vector should have the value 201907L in c++2b"
 #   endif
 # else // _LIBCPP_VERSION
 #   ifdef __cpp_lib_constexpr_vector
 #     error "__cpp_lib_constexpr_vector should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
-# if !defined(_LIBCPP_VERSION)
-#   ifndef __cpp_lib_coroutine
-#     error "__cpp_lib_coroutine should be defined in c++2b"
-#   endif
-#   if __cpp_lib_coroutine != 201902L
-#     error "__cpp_lib_coroutine should have the value 201902L in c++2b"
-#   endif
-# else // _LIBCPP_VERSION
-#   ifdef __cpp_lib_coroutine
-#     error "__cpp_lib_coroutine should not be defined because it is unimplemented in libc++!"
-#   endif
-# endif
+# ifndef __cpp_lib_coroutine
+#   error "__cpp_lib_coroutine should be defined in c++2b"
+# endif
+# if __cpp_lib_coroutine != 201902L
+#   error "__cpp_lib_coroutine should have the value 201902L in c++2b"
+# endif
 
 # if TEST_STD_VER > 17 && defined(__cpp_impl_destroying_delete) && __cpp_impl_destroying_delete >= 201806L
 #   ifndef __cpp_lib_destroying_delete
 #     error "__cpp_lib_destroying_delete should be defined in c++2b"
 #   endif
 #   if __cpp_lib_destroying_delete != 201806L
 #     error "__cpp_lib_destroying_delete should have the value 201806L in c++2b"
 #   endif

libcxx/test/support/coroutine_types.h

-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// 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 SUPPORT_COROUTINE_TYPES_H
-#define SUPPORT_COROUTINE_TYPES_H
-
-#include <experimental/coroutine>
-
-template <typename Ty> struct generator {
-  struct promise_type {
-    Ty current_value;
-    std::experimental::suspend_always yield_value(Ty value) {
-      this->current_value = value;
-      return {};
-    }
-    std::experimental::suspend_always initial_suspend() { return {}; }
-    std::experimental::suspend_always final_suspend() noexcept { return {}; }
-    generator get_return_object() { return generator{this}; };
-    void return_void() {}
-    void unhandled_exception() {}
-  };
-
-  struct iterator {
-    std::experimental::coroutine_handle<promise_type> _Coro;
-    bool _Done;
-
-    iterator(std::experimental::coroutine_handle<promise_type> Coro, bool Done)
-        : _Coro(Coro), _Done(Done) {}
-
-    iterator &operator++() {
-      _Coro.resume();
-      _Done = _Coro.done();
-      return *this;
-    }
-
-    bool operator==(iterator const &_Right) const {
-      return _Done == _Right._Done;
-    }
-
-    bool operator!=(iterator const &_Right) const { return !(*this == _Right); }
-
-    Ty const &operator*() const { return _Coro.promise().current_value; }
-
-    Ty const *operator->() const { return &(operator*()); }
-  };
-
-  iterator begin() {
-    p.resume();
-    return {p, p.done()};
-  }
-
-  iterator end() { return {p, true}; }
-
-  generator(generator &&rhs) : p(rhs.p) { rhs.p = nullptr; }
-
-  ~generator() {
-    if (p)
-      p.destroy();
-  }
-
-private:
-  explicit generator(promise_type *p)
-      : p(std::experimental::coroutine_handle<promise_type>::from_promise(*p)) {}
-
-  std::experimental::coroutine_handle<promise_type> p;
-};
-
-#endif // SUPPORT_COROUTINE_TYPES_H

libcxx/utils/generate_feature_test_macro_components.py

feature_test_macros = [ add_version_header(x) for x in [
     "name": "__cpp_lib_constexpr_vector",
     "values": { "c++20": 201907 },
     "headers": ["vector"],
     "unimplemented": True,
   }, {
     "name": "__cpp_lib_coroutine",
     "values": { "c++20": 201902 },
     "headers": ["coroutine"],
-    "unimplemented": True,
   }, {
     "name": "__cpp_lib_destroying_delete",
     "values": { "c++20": 201806 },
     "headers": ["new"],
     "test_suite_guard": "TEST_STD_VER > 17 && defined(__cpp_impl_destroying_delete) && __cpp_impl_destroying_delete >= 201806L",
     "libcxx_guard": "_LIBCPP_STD_VER > 17 && defined(__cpp_impl_destroying_delete) && __cpp_impl_destroying_delete >= 201806L",
   }, {
     "name": "__cpp_lib_enable_shared_from_this",

libcxx/utils/generate_header_inclusion_tests.py

 #
 mandatory_inclusions = {
     "algorithm": ["initializer_list"],
     "array": ["compare", "initializer_list"],
     "bitset": ["iosfwd", "string"],
     "chrono": ["compare"],
     "cinttypes": ["cstdint"],
     "complex.h": ["complex"],
-    # TODO "coroutine": ["compare"],
+    "coroutine": ["compare"],
     "deque": ["compare", "initializer_list"],
     "filesystem": ["compare"],
     "forward_list": ["compare", "initializer_list"],
     "ios": ["iosfwd"],
     "iostream": ["ios", "istream", "ostream", "streambuf"],
     "iterator": ["compare", "concepts"],
     "list": ["compare", "initializer_list"],
     "map": ["compare", "initializer_list"],

libcxx/utils/generate_header_tests.py

header_markup = {
     "strstream": ["ifndef _LIBCPP_HAS_NO_LOCALIZATION"],
 
     "wctype.h": ["ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS"],
     "cwctype": ["ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS"],
     "cwchar": ["ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS"],
     "wchar.h": ["ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS"],
 
     "experimental/coroutine": ["if defined(__cpp_coroutines)"],
+    "coroutine": ["if defined(__cpp_impl_coroutine)"],
     "experimental/regex": ["ifndef _LIBCPP_HAS_NO_LOCALIZATION"],
 }
 
 allowed_extensions = ['', '.h']
 indent_width = 4
 
 
 begin_pattern = """\