[coroutines] Add noop_coroutine to <experimental/coroutine>

A recent addition to Coroutines TS (https://wg21.link/p0913) adds a pre-defined
coroutine noop_coroutine that does nothing.

This patch implements require library types in <experimental/coroutine>

Related clang and llvm patches:

https://reviews.llvm.org/D45114
https://reviews.llvm.org/D45120

llvm-svn: 329237
This commit is contained in:
Gor Nishanov 2018-04-04 22:18:03 +00:00
parent f11eb3ebe7
commit 0f87a80795
2 changed files with 134 additions and 29 deletions

View File

@ -93,28 +93,28 @@ class _LIBCPP_TEMPLATE_VIS coroutine_handle;
template <>
class _LIBCPP_TEMPLATE_VIS coroutine_handle<void> {
public:
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
_LIBCPP_CONSTEXPR coroutine_handle() _NOEXCEPT : __handle_(nullptr) {}
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
_LIBCPP_CONSTEXPR coroutine_handle(nullptr_t) _NOEXCEPT : __handle_(nullptr) {}
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
coroutine_handle& operator=(nullptr_t) _NOEXCEPT {
__handle_ = nullptr;
return *this;
}
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
_LIBCPP_CONSTEXPR void* address() const _NOEXCEPT { return __handle_; }
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
_LIBCPP_CONSTEXPR explicit operator bool() const _NOEXCEPT { return __handle_; }
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
void operator()() { resume(); }
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
void resume() {
_LIBCPP_ASSERT(__is_suspended(),
"resume() can only be called on suspended coroutines");
@ -123,14 +123,14 @@ public:
__builtin_coro_resume(__handle_);
}
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
void destroy() {
_LIBCPP_ASSERT(__is_suspended(),
"destroy() can only be called on suspended coroutines");
__builtin_coro_destroy(__handle_);
}
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
bool done() const {
_LIBCPP_ASSERT(__is_suspended(),
"done() can only be called on suspended coroutines");
@ -138,7 +138,7 @@ public:
}
public:
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
static coroutine_handle from_address(void* __addr) _NOEXCEPT {
coroutine_handle __tmp;
__tmp.__handle_ = __addr;
@ -146,7 +146,7 @@ public:
}
// FIXME: Should from_address(nullptr) be allowed?
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
static coroutine_handle from_address(nullptr_t) _NOEXCEPT {
return coroutine_handle(nullptr);
}
@ -169,27 +169,27 @@ private:
};
// 18.11.2.7 comparison operators:
inline _LIBCPP_ALWAYS_INLINE
inline _LIBCPP_INLINE_VISIBILITY
bool operator==(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
return __x.address() == __y.address();
}
inline _LIBCPP_ALWAYS_INLINE
inline _LIBCPP_INLINE_VISIBILITY
bool operator!=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
return !(__x == __y);
}
inline _LIBCPP_ALWAYS_INLINE
inline _LIBCPP_INLINE_VISIBILITY
bool operator<(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
return less<void*>()(__x.address(), __y.address());
}
inline _LIBCPP_ALWAYS_INLINE
inline _LIBCPP_INLINE_VISIBILITY
bool operator>(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
return __y < __x;
}
inline _LIBCPP_ALWAYS_INLINE
inline _LIBCPP_INLINE_VISIBILITY
bool operator<=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
return !(__x > __y);
}
inline _LIBCPP_ALWAYS_INLINE
inline _LIBCPP_INLINE_VISIBILITY
bool operator>=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
return !(__x < __y);
}
@ -202,8 +202,8 @@ public:
// 18.11.2.1 construct/reset
using coroutine_handle<>::coroutine_handle;
#else
_LIBCPP_ALWAYS_INLINE coroutine_handle() _NOEXCEPT : _Base() {}
_LIBCPP_ALWAYS_INLINE coroutine_handle(nullptr_t) _NOEXCEPT : _Base(nullptr) {}
_LIBCPP_INLINE_VISIBILITY coroutine_handle() _NOEXCEPT : _Base() {}
_LIBCPP_INLINE_VISIBILITY coroutine_handle(nullptr_t) _NOEXCEPT : _Base(nullptr) {}
#endif
_LIBCPP_INLINE_VISIBILITY
coroutine_handle& operator=(nullptr_t) _NOEXCEPT {
@ -213,12 +213,12 @@ public:
_LIBCPP_INLINE_VISIBILITY
_Promise& promise() const {
return *reinterpret_cast<_Promise*>(
return *static_cast<_Promise*>(
__builtin_coro_promise(this->__handle_, __alignof(_Promise), false));
}
public:
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
static coroutine_handle from_address(void* __addr) _NOEXCEPT {
coroutine_handle __tmp;
__tmp.__handle_ = __addr;
@ -229,7 +229,7 @@ public:
// the deleted _Promise* overload doesn't make from_address(nullptr)
// ambiguous.
// FIXME: should from_address work with nullptr?
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
static coroutine_handle from_address(nullptr_t) _NOEXCEPT {
return coroutine_handle(nullptr);
}
@ -248,7 +248,7 @@ public:
"pointers to the coroutine's promise type; use 'from_promise' instead");
}
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
static coroutine_handle from_promise(_Promise& __promise) _NOEXCEPT {
typedef typename remove_cv<_Promise>::type _RawPromise;
coroutine_handle __tmp;
@ -259,21 +259,60 @@ public:
}
};
#if __has_builtin(__builtin_coro_noop)
struct noop_coroutine_promise {};
template <>
class _LIBCPP_TEMPLATE_VIS coroutine_handle<noop_coroutine_promise>
: public coroutine_handle<> {
using _Base = coroutine_handle<>;
using _Promise = noop_coroutine_promise;
public:
_LIBCPP_INLINE_VISIBILITY
_Promise& promise() const {
return *static_cast<_Promise*>(
__builtin_coro_promise(this->__handle_, __alignof(_Promise), false));
}
_LIBCPP_CONSTEXPR explicit operator bool() const _NOEXCEPT { return true; }
_LIBCPP_CONSTEXPR bool done() const _NOEXCEPT { return false; }
_LIBCPP_CONSTEXPR void operator()() const _NOEXCEPT {}
_LIBCPP_CONSTEXPR void resume() const _NOEXCEPT {}
_LIBCPP_CONSTEXPR void destroy() const _NOEXCEPT {}
private:
friend coroutine_handle<noop_coroutine_promise> noop_coroutine() _NOEXCEPT;
_LIBCPP_INLINE_VISIBILITY coroutine_handle() _NOEXCEPT {
this->__handle_ = __builtin_coro_noop();
}
};
using noop_coroutine_handle = coroutine_handle<noop_coroutine_promise>;
inline _LIBCPP_INLINE_VISIBILITY
noop_coroutine_handle noop_coroutine() _NOEXCEPT {
return {};
}
#endif // __has_builtin(__builtin_coro_noop)
struct _LIBCPP_TYPE_VIS suspend_never {
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
bool await_ready() const _NOEXCEPT { return true; }
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
void await_suspend(coroutine_handle<>) const _NOEXCEPT {}
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
void await_resume() const _NOEXCEPT {}
};
struct _LIBCPP_TYPE_VIS suspend_always {
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
bool await_ready() const _NOEXCEPT { return false; }
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
void await_suspend(coroutine_handle<>) const _NOEXCEPT {}
_LIBCPP_ALWAYS_INLINE
_LIBCPP_INLINE_VISIBILITY
void await_resume() const _NOEXCEPT {}
};

View File

@ -0,0 +1,66 @@
// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++98, c++03, c++11
// XFAIL: clang-5, clang-6
// <experimental/coroutine>
// struct noop_coroutine_promise;
// using noop_coroutine_handle = coroutine_handle<noop_coroutine_promise>;
// noop_coroutine_handle noop_coroutine() noexcept;
#include <experimental/coroutine>
#include <cassert>
#include <type_traits>
namespace coro = std::experimental::coroutines_v1;
static_assert(std::is_same<coro::coroutine_handle<coro::noop_coroutine_promise>, coro::noop_coroutine_handle>::value, "");
static_assert(std::is_same<decltype(coro::noop_coroutine()), coro::noop_coroutine_handle>::value, "");
// template <> struct coroutine_handle<noop_coroutine_promise> : coroutine_handle<>
// {
// // 18.11.2.7 noop observers
// constexpr explicit operator bool() const noexcept;
// constexpr bool done() const noexcept;
// // 18.11.2.8 noop resumption
// constexpr void operator()() const noexcept;
// constexpr void resume() const noexcept;
// constexpr void destroy() const noexcept;
// // 18.11.2.9 noop promise access
// noop_coroutine_promise& promise() const noexcept;
// // 18.11.2.10 noop address
// constexpr void* address() const noexcept;
int main()
{
auto h = coro::noop_coroutine();
coro::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.address() != nullptr);
assert(coro::coroutine_handle<>::from_address(h.address()) == base);
}