1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
// Copyright (C) 2006-2024 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// 20.6.6.2 Template class shared_ptr [util.smartptr.shared]
// { dg-do run { target c++11 } }
// { dg-additional-options "-pthread" { target pthread } }
// { dg-add-options libatomic }
// { dg-require-gthreads "" }
// { dg-require-cstdint "" }
#include <memory>
#include <random>
#include <vector>
#include <iostream>
#include <cstdlib>
#include <thread>
#include <atomic>
#include <functional>
#include <testsuite_hooks.h>
#ifdef _GLIBCXX_HAVE_UNISTD_H
#include <unistd.h> // To test for _POSIX_THREAD_PRIORITY_SCHEDULING
#endif
/* This (brute-force) tests the atomicity and thus thread safety of the
* shared_ptr <- weak_ptr
* assignment operation by allocating a test object, retrieving a weak
* reference to it, and letting a number of threads repeatedly create strong
* references from the weak reference.
* Specifically, this tests the function _Sp_counted_base<true>::add_ref_lock()
*/
const unsigned int HAMMER_MAX_THREADS = 10;
const unsigned int POOL_SIZE = 1000;
const unsigned long HAMMER_REPEAT = 100000;
const unsigned long KILL_ONE_IN = 1000;
struct A
{
static std::atomic<int> counter;
A() { counter.fetch_add(1, std::memory_order_relaxed); }
~A() { counter.fetch_sub(1, std::memory_order_relaxed); }
};
std::atomic<int> A::counter{ 0 };
typedef std::shared_ptr<A> sp_A_t;
typedef std::weak_ptr<A> wp_A_t;
typedef std::vector<sp_A_t> sp_vector_t;
typedef std::vector<wp_A_t> wp_vector_t;
struct shared_and_weak_pools
{
sp_vector_t& shared_pool;
wp_vector_t& weak_pool;
shared_and_weak_pools(sp_vector_t& _shared_pool, wp_vector_t& _weak_pool)
: shared_pool(_shared_pool), weak_pool(_weak_pool)
{ }
};
void thread_hammer_and_kill(shared_and_weak_pools& pools)
{
std::mt19937 urbg;
std::uniform_int_distribution<> dist(0, KILL_ONE_IN - 1);
sp_vector_t::iterator cur_shared = pools.shared_pool.begin();
wp_vector_t::iterator cur_weak = pools.weak_pool.begin();
for (unsigned int i = 0; i < HAMMER_REPEAT; ++i)
{
try
{
sp_A_t strong(*cur_weak);
}
catch (std::bad_weak_ptr& exception)
{
++cur_weak;
if (cur_weak == pools.weak_pool.end())
break;
}
if (dist(urbg) == 0)
{
cur_shared->reset();
++cur_shared;
}
}
}
void thread_hammer(wp_vector_t& weak_pool)
{
wp_vector_t::iterator cur_weak = weak_pool.begin();
for (unsigned int i = 0; i < HAMMER_REPEAT; ++i)
{
try
{
sp_A_t strong(*cur_weak);
}
catch (std::bad_weak_ptr& exception)
{
++cur_weak;
if (cur_weak == weak_pool.end())
break;
}
}
}
void
test01()
{
sp_vector_t obj_pool(POOL_SIZE);
for(auto& obj : obj_pool)
obj.reset(new A);
// Obtain weak references.
std::vector<wp_vector_t> weak_pool(HAMMER_MAX_THREADS, wp_vector_t(obj_pool.begin(), obj_pool.end()));
// Launch threads with pointer to weak reference.
std::thread threads[HAMMER_MAX_THREADS];
#if defined(__sun) && defined(__svr4__) && _XOPEN_VERSION >= 500
pthread_setconcurrency (HAMMER_MAX_THREADS);
#endif
shared_and_weak_pools pools(obj_pool, weak_pool[0]);
threads[0] = std::thread(thread_hammer_and_kill, std::ref(pools));
for (unsigned int worker = 1; worker < HAMMER_MAX_THREADS; worker++)
threads[worker] = std::thread(thread_hammer, std::ref(weak_pool[worker]));
// Wait for threads to complete, then check integrity of reference.
for (auto& thread : threads)
thread.join();
obj_pool.clear();
VERIFY( A::counter == 0 );
}
int
main()
{
test01();
return 0;
}
|
