forked from OSchip/llvm-project
131 lines
4.2 KiB
C++
131 lines
4.2 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// UNSUPPORTED: libcpp-has-no-threads
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// UNSUPPORTED: c++98, c++03
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// <future>
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// class shared_future<R>
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// template <class Clock, class Duration>
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// future_status
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// wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
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#include <future>
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#include <atomic>
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#include <cassert>
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enum class WorkerThreadState { Uninitialized, AllowedToRun, Exiting };
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typedef std::chrono::milliseconds ms;
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std::atomic<WorkerThreadState> thread_state(WorkerThreadState::Uninitialized);
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void set_worker_thread_state(WorkerThreadState state)
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{
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thread_state.store(state, std::memory_order_relaxed);
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}
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void wait_for_worker_thread_state(WorkerThreadState state)
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{
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while (thread_state.load(std::memory_order_relaxed) != state);
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}
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void func1(std::promise<int> p)
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{
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wait_for_worker_thread_state(WorkerThreadState::AllowedToRun);
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p.set_value(3);
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set_worker_thread_state(WorkerThreadState::Exiting);
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}
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int j = 0;
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void func3(std::promise<int&> p)
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{
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wait_for_worker_thread_state(WorkerThreadState::AllowedToRun);
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j = 5;
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p.set_value(j);
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set_worker_thread_state(WorkerThreadState::Exiting);
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}
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void func5(std::promise<void> p)
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{
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wait_for_worker_thread_state(WorkerThreadState::AllowedToRun);
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p.set_value();
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set_worker_thread_state(WorkerThreadState::Exiting);
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}
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int main()
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{
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typedef std::chrono::high_resolution_clock Clock;
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{
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typedef int T;
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std::promise<T> p;
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std::shared_future<T> f = p.get_future();
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std::thread(func1, std::move(p)).detach();
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assert(f.valid());
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assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout);
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assert(f.valid());
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// allow the worker thread to produce the result and wait until the worker is done
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set_worker_thread_state(WorkerThreadState::AllowedToRun);
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wait_for_worker_thread_state(WorkerThreadState::Exiting);
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assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready);
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assert(f.valid());
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Clock::time_point t0 = Clock::now();
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f.wait();
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Clock::time_point t1 = Clock::now();
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assert(f.valid());
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assert(t1-t0 < ms(5));
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}
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{
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typedef int& T;
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std::promise<T> p;
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std::shared_future<T> f = p.get_future();
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std::thread(func3, std::move(p)).detach();
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assert(f.valid());
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assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout);
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assert(f.valid());
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// allow the worker thread to produce the result and wait until the worker is done
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set_worker_thread_state(WorkerThreadState::AllowedToRun);
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wait_for_worker_thread_state(WorkerThreadState::Exiting);
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assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready);
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assert(f.valid());
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Clock::time_point t0 = Clock::now();
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f.wait();
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Clock::time_point t1 = Clock::now();
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assert(f.valid());
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assert(t1-t0 < ms(5));
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}
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{
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typedef void T;
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std::promise<T> p;
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std::shared_future<T> f = p.get_future();
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std::thread(func5, std::move(p)).detach();
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assert(f.valid());
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assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout);
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assert(f.valid());
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// allow the worker thread to produce the result and wait until the worker is done
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set_worker_thread_state(WorkerThreadState::AllowedToRun);
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wait_for_worker_thread_state(WorkerThreadState::Exiting);
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assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready);
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assert(f.valid());
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Clock::time_point t0 = Clock::now();
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f.wait();
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Clock::time_point t1 = Clock::now();
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assert(f.valid());
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assert(t1-t0 < ms(5));
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}
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}
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