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-no-exceptions
11 // UNSUPPORTED: libcpp-has-no-threads
12
13 // <condition_variable>
14
15 // class condition_variable_any;
16
17 // RUN: %build
18 // RUN: %run 1
19 // RUN: %run 2
20 // RUN: %run 3
21 // RUN: %run 4
22 // RUN: %run 5
23 // RUN: %run 6
24
25 // -----------------------------------------------------------------------------
26 // Overview
27 // Check that std::terminate is called if wait(...) fails to meet its post
28 // conditions. This can happen when reacquiring the mutex throws
29 // an exception.
30 //
31 // The following methods are tested within this file
32 // 1. void wait(Lock& lock);
33 // 2. void wait(Lock& lock, Pred);
34 // 3. void wait_for(Lock& lock, Duration);
35 // 4. void wait_for(Lock& lock, Duration, Pred);
36 // 5. void wait_until(Lock& lock, TimePoint);
37 // 6. void wait_until(Lock& lock, TimePoint, Pred);
38 //
39 // Plan
40 // 1 Create a mutex type, 'ThrowingMutex', that throws when the lock is acquired
41 // for the *second* time.
42 //
43 // 2 Replace the terminate handler with one that exits with a '0' exit code.
44 //
45 // 3 Create a 'condition_variable_any' object 'cv' and a 'ThrowingMutex'
46 // object 'm' and lock 'm'.
47 //
48 // 4 Start a thread 'T2' that will notify 'cv' once 'm' has been unlocked.
49 //
50 // 5 From the main thread call the specified wait method on 'cv' with 'm'.
51 // When 'T2' notifies 'cv' and the wait method attempts to re-lock
52 // 'm' an exception will be thrown from 'm.lock()'.
53 //
54 // 6 Check that control flow does not return from the wait method and that
55 // terminate is called (If the program exits with a 0 exit code we know
56 // that terminate has been called)
57
58
59 #include <condition_variable>
60 #include <atomic>
61 #include <thread>
62 #include <chrono>
63 #include <string>
64 #include <cstdlib>
65 #include <cassert>
66
my_terminate()67 void my_terminate() {
68 std::_Exit(0); // Use _Exit to prevent cleanup from taking place.
69 }
70
71 // The predicate used in the cv.wait calls.
72 bool pred = false;
pred_function()73 bool pred_function() {
74 return pred == true;
75 }
76
77 class ThrowingMutex
78 {
79 std::atomic_bool locked;
80 unsigned state = 0;
81 ThrowingMutex(const ThrowingMutex&) = delete;
82 ThrowingMutex& operator=(const ThrowingMutex&) = delete;
83 public:
ThrowingMutex()84 ThrowingMutex() {
85 locked = false;
86 }
87 ~ThrowingMutex() = default;
88
lock()89 void lock() {
90 locked = true;
91 if (++state == 2) {
92 assert(pred); // Check that we actually waited until we were signaled.
93 throw 1; // this throw should end up calling terminate()
94 }
95 }
96
unlock()97 void unlock() { locked = false; }
isLocked() const98 bool isLocked() const { return locked == true; }
99 };
100
101 ThrowingMutex mut;
102 std::condition_variable_any cv;
103
signal_me()104 void signal_me() {
105 while (mut.isLocked()) {} // wait until T1 releases mut inside the cv.wait call.
106 pred = true;
107 cv.notify_one();
108 }
109
110 typedef std::chrono::system_clock Clock;
111 typedef std::chrono::milliseconds MS;
112
main(int argc,char ** argv)113 int main(int argc, char** argv) {
114 assert(argc == 2);
115 int id = std::stoi(argv[1]);
116 assert(id >= 1 && id <= 6);
117 std::set_terminate(my_terminate); // set terminate after std::stoi because it can throw.
118 MS wait(250);
119 try {
120 mut.lock();
121 assert(pred == false);
122 std::thread(signal_me).detach();
123 switch (id) {
124 case 1: cv.wait(mut); break;
125 case 2: cv.wait(mut, pred_function); break;
126 case 3: cv.wait_for(mut, wait); break;
127 case 4: cv.wait_for(mut, wait, pred_function); break;
128 case 5: cv.wait_until(mut, Clock::now() + wait); break;
129 case 6: cv.wait_until(mut, Clock::now() + wait, pred_function); break;
130 default: assert(false);
131 }
132 } catch (...) {}
133 assert(false);
134 }
135