1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___COROUTINE_NOOP_COROUTINE_HANDLE_H 10 #define _LIBCPP___COROUTINE_NOOP_COROUTINE_HANDLE_H 11 12 #include <__config> 13 #include <__coroutine/coroutine_handle.h> 14 15 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 16 # pragma GCC system_header 17 #endif 18 19 #if _LIBCPP_STD_VER >= 20 20 21 _LIBCPP_BEGIN_NAMESPACE_STD 22 23 # if __has_builtin(__builtin_coro_noop) || defined(_LIBCPP_COMPILER_GCC) 24 25 // [coroutine.noop] 26 // [coroutine.promise.noop] 27 struct noop_coroutine_promise {}; 28 29 // [coroutine.handle.noop] 30 template <> 31 struct _LIBCPP_TEMPLATE_VIS coroutine_handle<noop_coroutine_promise> { 32 public: 33 // [coroutine.handle.noop.conv], conversion 34 _LIBCPP_HIDE_FROM_ABI constexpr operator coroutine_handle<>() const noexcept { 35 return coroutine_handle<>::from_address(address()); 36 } 37 38 // [coroutine.handle.noop.observers], observers 39 _LIBCPP_HIDE_FROM_ABI constexpr explicit operator bool() const noexcept { return true; } 40 _LIBCPP_HIDE_FROM_ABI constexpr bool done() const noexcept { return false; } 41 42 // [coroutine.handle.noop.resumption], resumption 43 _LIBCPP_HIDE_FROM_ABI constexpr void operator()() const noexcept {} 44 _LIBCPP_HIDE_FROM_ABI constexpr void resume() const noexcept {} 45 _LIBCPP_HIDE_FROM_ABI constexpr void destroy() const noexcept {} 46 47 // [coroutine.handle.noop.promise], promise access 48 _LIBCPP_HIDE_FROM_ABI noop_coroutine_promise& promise() const noexcept { 49 return *static_cast<noop_coroutine_promise*>( 50 __builtin_coro_promise(this->__handle_, alignof(noop_coroutine_promise), false)); 51 } 52 53 // [coroutine.handle.noop.address], address 54 _LIBCPP_HIDE_FROM_ABI constexpr void* address() const noexcept { return __handle_; } 55 56 private: 57 _LIBCPP_HIDE_FROM_ABI friend coroutine_handle<noop_coroutine_promise> noop_coroutine() noexcept; 58 59 # if __has_builtin(__builtin_coro_noop) 60 _LIBCPP_HIDE_FROM_ABI coroutine_handle() noexcept { this->__handle_ = __builtin_coro_noop(); } 61 62 void* __handle_ = nullptr; 63 64 # elif defined(_LIBCPP_COMPILER_GCC) 65 // GCC doesn't implement __builtin_coro_noop(). 66 // Construct the coroutine frame manually instead. 67 struct __noop_coroutine_frame_ty_ { 68 static void __dummy_resume_destroy_func() {} 69 70 void (*__resume_)() = __dummy_resume_destroy_func; 71 void (*__destroy_)() = __dummy_resume_destroy_func; 72 struct noop_coroutine_promise __promise_; 73 }; 74 75 static __noop_coroutine_frame_ty_ __noop_coroutine_frame_; 76 77 void* __handle_ = &__noop_coroutine_frame_; 78 79 _LIBCPP_HIDE_FROM_ABI coroutine_handle() noexcept = default; 80 81 # endif // __has_builtin(__builtin_coro_noop) 82 }; 83 84 using noop_coroutine_handle = coroutine_handle<noop_coroutine_promise>; 85 86 # if defined(_LIBCPP_COMPILER_GCC) 87 inline noop_coroutine_handle::__noop_coroutine_frame_ty_ noop_coroutine_handle::__noop_coroutine_frame_{}; 88 # endif 89 90 // [coroutine.noop.coroutine] 91 inline _LIBCPP_HIDE_FROM_ABI noop_coroutine_handle noop_coroutine() noexcept { return noop_coroutine_handle(); } 92 93 # endif // __has_builtin(__builtin_coro_noop) || defined(_LIBCPP_COMPILER_GCC) 94 95 _LIBCPP_END_NAMESPACE_STD 96 97 #endif // __LIBCPP_STD_VER >= 20 98 99 #endif // _LIBCPP___COROUTINE_NOOP_COROUTINE_HANDLE_H 100