29ef92b905
This makes the tests less flaky and also makes a few other refactorings like using traits instead of .compile.fail.cpp tests.
109 lines
2.8 KiB
C++
109 lines
2.8 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: no-threads
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// UNSUPPORTED: c++03, c++11
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// <shared_mutex>
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// class shared_timed_mutex;
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// void lock();
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#include <shared_mutex>
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#include <atomic>
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#include <cassert>
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#include <chrono>
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#include <thread>
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#include <vector>
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#include "make_test_thread.h"
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int main(int, char**) {
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// Exclusive-lock a mutex that is not locked yet. This should succeed.
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{
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std::shared_timed_mutex m;
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m.lock();
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m.unlock();
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}
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// Exclusive-lock a mutex that is already locked exclusively. This should block until it is unlocked.
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{
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std::atomic<bool> ready(false);
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std::shared_timed_mutex m;
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m.lock();
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std::atomic<bool> is_locked_from_main(true);
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std::thread t = support::make_test_thread([&] {
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ready = true;
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m.lock();
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assert(!is_locked_from_main);
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m.unlock();
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});
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while (!ready)
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/* spin */;
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// We would rather signal this after we unlock, but that would create a race condition.
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// We instead signal it before we unlock, which means that it's technically possible for the thread
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// to take the lock while we're still holding it and for the test to still pass.
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is_locked_from_main = false;
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m.unlock();
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t.join();
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}
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// Exclusive-lock a mutex that is already share-locked. This should block until it is unlocked.
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{
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std::atomic<bool> ready(false);
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std::shared_timed_mutex m;
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m.lock_shared();
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std::atomic<bool> is_locked_from_main(true);
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std::thread t = support::make_test_thread([&] {
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ready = true;
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m.lock();
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assert(!is_locked_from_main);
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m.unlock();
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});
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while (!ready)
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/* spin */;
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// We would rather signal this after we unlock, but that would create a race condition.
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// We instead signal it before we unlock, which means that it's technically possible for
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// the thread to take the lock while we're still holding it and for the test to still pass.
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is_locked_from_main = false;
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m.unlock_shared();
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t.join();
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}
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// Make sure that at most one thread can acquire the mutex concurrently.
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{
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std::atomic<int> counter(0);
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std::shared_timed_mutex mutex;
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std::vector<std::thread> threads;
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for (int i = 0; i != 10; ++i) {
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threads.push_back(support::make_test_thread([&] {
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mutex.lock();
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counter++;
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assert(counter == 1);
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counter--;
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mutex.unlock();
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}));
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}
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for (auto& t : threads)
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t.join();
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}
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return 0;
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}
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