1 // RUN: %clangxx_tsan -O1 %s %link_libcxx_tsan -o %t && %deflake %env_tsan_opts=atexit_sleep_ms=50 %run %t 2>&1 | FileCheck --check-prefix=CHECK-REPORT %s
2 
3 #include <atomic>
4 #include <cassert>
5 #include <stdio.h>
6 #include <thread>
7 
8 #define NUM_ORDS 16
9 #define NUM_THREADS NUM_ORDS * 2
10 struct node {
11   int val;
12 };
13 std::atomic<node *> _nodes[NUM_THREADS] = {};
14 
15 void f1(int i) {
16   auto n = new node();
17   n->val = 42;
18   _nodes[i].store(n, std::memory_order_release);
19 }
20 
21 template <int version>
22 void f2(int i, std::memory_order mo, std::memory_order fmo) {
23   node *expected = nullptr;
24   while (expected == nullptr) {
25     _nodes[i].compare_exchange_weak(expected, nullptr, mo, fmo);
26   };
27 
28   ++expected->val;
29   assert(expected->val == 43);
30 }
31 
32 struct MemOrdSuccFail {
33   std::memory_order mo;
34   std::memory_order fmo;
35 };
36 
37 MemOrdSuccFail OrdList[NUM_ORDS] = {
38     {std::memory_order_release, std::memory_order_relaxed},
39     {std::memory_order_release, std::memory_order_acquire},
40     {std::memory_order_release, std::memory_order_consume},
41     {std::memory_order_release, std::memory_order_seq_cst},
42 
43     {std::memory_order_acq_rel, std::memory_order_relaxed},
44     {std::memory_order_acq_rel, std::memory_order_acquire},
45     {std::memory_order_acq_rel, std::memory_order_consume},
46     {std::memory_order_acq_rel, std::memory_order_seq_cst},
47 
48     {std::memory_order_seq_cst, std::memory_order_relaxed},
49     {std::memory_order_seq_cst, std::memory_order_acquire},
50     {std::memory_order_seq_cst, std::memory_order_consume},
51     {std::memory_order_seq_cst, std::memory_order_seq_cst},
52 
53     {std::memory_order_relaxed, std::memory_order_relaxed},
54     {std::memory_order_relaxed, std::memory_order_acquire},
55     {std::memory_order_relaxed, std::memory_order_consume},
56     {std::memory_order_relaxed, std::memory_order_seq_cst},
57 };
58 
59 int main() {
60   std::thread threads[NUM_THREADS];
61   int ords = 0;
62 
63   // Instantiate a new f2 for each MO so we can dedup reports and actually
64   // make sure relaxed FMO triggers a warning for every different MO.
65   for (unsigned t = 0; t < 8; t += 2) {
66     threads[t] = std::thread(f1, t);
67     threads[t + 1] = std::thread(f2<0>, t, OrdList[ords].mo, OrdList[ords].fmo);
68     threads[t].join();
69     threads[t + 1].join();
70     ords++;
71   }
72 
73   for (unsigned t = 8; t < 16; t += 2) {
74     threads[t] = std::thread(f1, t);
75     threads[t + 1] = std::thread(f2<1>, t, OrdList[ords].mo, OrdList[ords].fmo);
76     threads[t].join();
77     threads[t + 1].join();
78     ords++;
79   }
80 
81   for (unsigned t = 16; t < 24; t += 2) {
82     threads[t] = std::thread(f1, t);
83     threads[t + 1] = std::thread(f2<2>, t, OrdList[ords].mo, OrdList[ords].fmo);
84     threads[t].join();
85     threads[t + 1].join();
86     ords++;
87   }
88 
89   for (unsigned t = 24; t < 32; t += 2) {
90     threads[t] = std::thread(f1, t);
91     threads[t + 1] = std::thread(f2<3>, t, OrdList[ords].mo, OrdList[ords].fmo);
92     threads[t].join();
93     threads[t + 1].join();
94     ords++;
95   }
96 
97   fprintf(stderr, "DONE\n");
98   return 0;
99 }
100 
101 // CHECK-REPORT: WARNING: ThreadSanitizer: data race
102 // CHECK-REPORT: WARNING: ThreadSanitizer: data race
103 // CHECK-REPORT: WARNING: ThreadSanitizer: data race
104 // CHECK-REPORT: WARNING: ThreadSanitizer: data race
105 // CHECK-REPORT: DONE
106 // CHECK-REPORT: ThreadSanitizer: reported 4 warnings
107