Author: ericwf
Date: Thu Jun 15 19:36:17 2017
New Revision: 305536
URL: http://llvm.org/viewvc/llvm-project?rev=305536&view=rev
Log:
Allow coroutine_handle<const T> to support creation from const references to
the promise_type
It seems conceivable that a user would need to get a coroutine handle
having only a const reference to the promise_type, for example from
within a const member function of the promise.
This patch allows that use case. A coroutine_handle<const T> can be used
in essentially the same way a coroutine_handle<T>, ie to start and destroy
the coroutine. The constness of the promise doesn't/shouldn't propagate
to the handle.
Modified:
libcxx/trunk/include/experimental/coroutine
libcxx/trunk/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp
Modified: libcxx/trunk/include/experimental/coroutine
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/experimental/coroutine?rev=305536&r1=305535&r2=305536&view=diff
==============================================================================
--- libcxx/trunk/include/experimental/coroutine (original)
+++ libcxx/trunk/include/experimental/coroutine Thu Jun 15 19:36:17 2017
@@ -250,9 +250,11 @@ public:
_LIBCPP_ALWAYS_INLINE
static coroutine_handle from_promise(_Promise& __promise) _NOEXCEPT {
+ typedef typename remove_cv<_Promise>::type _RawPromise;
coroutine_handle __tmp;
- __tmp.__handle_ = __builtin_coro_promise(_VSTD::addressof(__promise),
- __alignof(_Promise), true);
+ __tmp.__handle_ = __builtin_coro_promise(
+ _VSTD::addressof(const_cast<_RawPromise&>(__promise)),
+ __alignof(_Promise), true);
return __tmp;
}
};
Modified:
libcxx/trunk/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp?rev=305536&r1=305535&r2=305536&view=diff
==============================================================================
---
libcxx/trunk/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp
(original)
+++
libcxx/trunk/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp
Thu Jun 15 19:36:17 2017
@@ -28,6 +28,39 @@
namespace coro = std::experimental;
+struct MyCoro {
+ struct promise_type {
+ void unhandled_exception() {}
+ void return_void() {}
+ coro::suspend_never initial_suspend() { return {}; }
+ coro::suspend_never final_suspend() { 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 = coro::coroutine_handle<promise_type>;
+ using CCH = coro::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 coro::suspend_never{};
+}
+
template <class Promise>
void do_test(coro::coroutine_handle<Promise>&& H) {
@@ -46,4 +79,6 @@ void do_test(coro::coroutine_handle<Prom
int main()
{
do_test(coro::coroutine_handle<int>{});
+ do_test(coro::coroutine_handle<const int>{});
+ do_runtime_test();
}
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