1 //===----------------------------------------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 // UNSUPPORTED: libcpp-has-no-threads
11
12 // <condition_variable>
13
14 // class condition_variable_any;
15
16 // RUN: %build
17 // RUN: %run 1
18 // RUN: %run 2
19 // RUN: %run 3
20 // RUN: %run 4
21 // RUN: %run 5
22 // RUN: %run 6
23
24 // -----------------------------------------------------------------------------
25 // Overview
26 // Check that std::terminate is called if wait(...) fails to meet it's post
27 // conditions. This can happens when reacquiring the mutex throws
28 // an exception.
29 //
30 // The following methods are tested within this file
31 // 1. void wait(Lock& lock);
32 // 2. void wait(Lock& lock, Pred);
33 // 3. void wait_for(Lock& lock, Duration);
34 // 4. void wait_for(Lock& lock, Duration, Pred);
35 // 5. void wait_until(Lock& lock, TimePoint);
36 // 6. void wait_until(Lock& lock, TimePoint, Pred);
37 //
38 // Plan
39 // 1 Create a mutex type, 'ThrowingMutex', that throws when the lock is aquired
40 // for the *second* time.
41 //
42 // 2 Replace the terminate handler with one that exits with a '0' exit code.
43 //
44 // 3 Create a 'condition_variable_any' object 'cv' and a 'ThrowingMutex'
45 // object 'm' and lock 'm'.
46 //
47 // 4 Start a thread 'T2' that will notify 'cv' once 'm' has been unlocked.
48 //
49 // 5 From the main thread call the specified wait method on 'cv' with 'm'.
50 // When 'T2' notifies 'cv' and the wait method attempts to re-lock
51 // 'm' an exception will be thrown from 'm.lock()'.
52 //
53 // 6 Check that control flow does not return from the wait method and that
54 // terminate is called (If the program exits with a 0 exit code we know
55 // that terminate has been called)
56
57
58 #include <condition_variable>
59 #include <atomic>
60 #include <thread>
61 #include <chrono>
62 #include <string>
63 #include <cstdlib>
64 #include <cassert>
65
my_terminate()66 void my_terminate() {
67 std::_Exit(0); // Use _Exit to prevent cleanup from taking place.
68 }
69
70 // The predicate used in the cv.wait calls.
71 bool pred = false;
pred_function()72 bool pred_function() {
73 return pred == true;
74 }
75
76 class ThrowingMutex
77 {
78 std::atomic_bool locked;
79 unsigned state = 0;
80 ThrowingMutex(const ThrowingMutex&) = delete;
81 ThrowingMutex& operator=(const ThrowingMutex&) = delete;
82 public:
ThrowingMutex()83 ThrowingMutex() {
84 locked = false;
85 }
86 ~ThrowingMutex() = default;
87
lock()88 void lock() {
89 locked = true;
90 if (++state == 2) {
91 assert(pred); // Check that we actually waited until we were signaled.
92 throw 1; // this throw should end up calling terminate()
93 }
94 }
95
unlock()96 void unlock() { locked = false; }
isLocked() const97 bool isLocked() const { return locked == true; }
98 };
99
100 ThrowingMutex mut;
101 std::condition_variable_any cv;
102
signal_me()103 void signal_me() {
104 while (mut.isLocked()) {} // wait until T1 releases mut inside the cv.wait call.
105 pred = true;
106 cv.notify_one();
107 }
108
109 typedef std::chrono::system_clock Clock;
110 typedef std::chrono::milliseconds MS;
111
main(int argc,char ** argv)112 int main(int argc, char** argv) {
113 assert(argc == 2);
114 int id = std::stoi(argv[1]);
115 assert(id >= 1 && id <= 6);
116 std::set_terminate(my_terminate); // set terminate after std::stoi because it can throw.
117 MS wait(250);
118 try {
119 mut.lock();
120 assert(pred == false);
121 std::thread(signal_me).detach();
122 switch (id) {
123 case 1: cv.wait(mut); break;
124 case 2: cv.wait(mut, pred_function); break;
125 case 3: cv.wait_for(mut, wait); break;
126 case 4: cv.wait_for(mut, wait, pred_function); break;
127 case 5: cv.wait_until(mut, Clock::now() + wait); break;
128 case 6: cv.wait_until(mut, Clock::now() + wait, pred_function); break;
129 default: assert(false);
130 }
131 } catch (...) {}
132 assert(false);
133 }
134