1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include <cassert>
10#include <cxxabi.h>
11
12#include "test_macros.h"
13
14#ifndef TEST_HAS_NO_THREADS
15# include <thread>
16# include "make_test_thread.h"
17#endif
18
19// Ensure that we initialize each variable once and only once.
20namespace test1 {
21 static int run_count = 0;
22 int increment() {
23 ++run_count;
24 return 0;
25 }
26 void helper() {
27 static int a = increment();
28 ((void)a);
29 }
30 void test() {
31 static int a = increment(); ((void)a);
32 assert(run_count == 1);
33 static int b = increment(); ((void)b);
34 assert(run_count == 2);
35 helper();
36 assert(run_count == 3);
37 helper();
38 assert(run_count == 3);
39 }
40}
41
42// When initialization fails, ensure that we try to initialize it again next
43// time.
44namespace test2 {
45#ifndef TEST_HAS_NO_EXCEPTIONS
46 static int run_count = 0;
47 int increment() {
48 ++run_count;
49 throw 0;
50 }
51 void helper() {
52 try {
53 static int a = increment();
54 assert(false);
55 ((void)a);
56 } catch (...) {}
57 }
58 void test() {
59 helper();
60 assert(run_count == 1);
61 helper();
62 assert(run_count == 2);
63 }
64#else
65 void test() {}
66#endif
67}
68
69// Check that we can initialize a second value while initializing a first.
70namespace test3 {
71 int zero() {
72 return 0;
73 }
74
75 int one() {
76 static int b = zero(); ((void)b);
77 return 0;
78 }
79
80 void test() {
81 static int a = one(); ((void)a);
82 }
83}
84
85#ifndef TEST_HAS_NO_THREADS
86// A simple thread test of two threads racing to initialize a variable. This
87// isn't guaranteed to catch any particular threading problems.
88namespace test4 {
89 static int run_count = 0;
90 int increment() {
91 ++run_count;
92 return 0;
93 }
94
95 void helper() {
96 static int a = increment(); ((void)a);
97 }
98
99 void test() {
100 std::thread t1 = support::make_test_thread(helper);
101 std::thread t2 = support::make_test_thread(helper);
102 t1.join();
103 t2.join();
104 assert(run_count == 1);
105 }
106}
107
108// Check that we don't re-initialize a static variable even when it's
109// encountered from two different threads.
110namespace test5 {
111 static int run_count = 0;
112 int zero() {
113 ++run_count;
114 return 0;
115 }
116
117 int one() {
118 static int b = zero(); ((void)b);
119 return 0;
120 }
121
122 void another_helper() {
123 static int a = one(); ((void)a);
124 }
125
126 void helper() {
127 static int a = one(); ((void)a);
128 std::thread t = support::make_test_thread(another_helper);
129 t.join();
130 }
131
132 void test() {
133 std::thread t = support::make_test_thread(helper);
134 t.join();
135 assert(run_count == 1);
136 }
137}
138#endif /* TEST_HAS_NO_THREADS */
139
140int main(int, char**)
141{
142 test1::test();
143 test2::test();
144 test3::test();
145#ifndef TEST_HAS_NO_THREADS
146 test4::test();
147 test5::test();
148#endif
149
150 return 0;
151}
152

source code of libcxxabi/test/test_guard.pass.cpp