libstdc++-v3/testsuite/20_util/shared_ptr/thread/default_weaktoshared.cc

   1 // Copyright (C) 2006-2018 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // 20.6.6.2 Template class shared_ptr [util.smartptr.shared]
  19
  20 // { dg-do run }
  21 // { dg-options "-pthread"  }
  22 // { dg-require-effective-target c++11 }
  23 // { dg-require-effective-target pthread }
  24
  25 #include <memory>
  26 #include <random>
  27 #include <vector>
  28 #include <iostream>
  29 #include <cstdlib>
  30 #include <thread>
  31 #include <atomic>
  32 #include <functional>
  33 #include <testsuite_hooks.h>
  34
  35 #ifdef _GLIBCXX_HAVE_UNISTD_H
  36 #include <unistd.h>     // To test for _POSIX_THREAD_PRIORITY_SCHEDULING
  37 #endif
  38
  39 /* This (brute-force) tests the atomicity and thus thread safety of the
  40  * shared_ptr <- weak_ptr
  41  * assignment operation by allocating a test object, retrieving a weak
  42  * reference to it, and letting a number of threads repeatedly create strong
  43  * references from the weak reference.
  44  * Specifically, this tests the function _Sp_counted_base<true>::add_ref_lock()
  45  */
  46
  47
  48 const unsigned int HAMMER_MAX_THREADS = 10;
  49 const unsigned int POOL_SIZE = 1000;
  50 const unsigned long HAMMER_REPEAT = 100000;
  51 const unsigned long KILL_ONE_IN = 1000;
  52
  53 struct A
  54 {
  55   static std::atomic<int> counter;
  56   A() { counter.fetch_add(1, std::memory_order_relaxed); }
  57  ~A() { counter.fetch_sub(1, std::memory_order_relaxed); }
  58 };
  59
  60 std::atomic<int> A::counter{ 0 };
  61
  62 typedef std::shared_ptr<A> sp_A_t;
  63 typedef std::weak_ptr<A> wp_A_t;
  64
  65 typedef std::vector<sp_A_t> sp_vector_t;
  66 typedef std::vector<wp_A_t> wp_vector_t;
  67
  68 struct shared_and_weak_pools
  69 {
  70   sp_vector_t& shared_pool;
  71   wp_vector_t& weak_pool;
  72
  73   shared_and_weak_pools(sp_vector_t& _shared_pool, wp_vector_t& _weak_pool)
  74     : shared_pool(_shared_pool), weak_pool(_weak_pool)
  75     { }
  76 };
  77
  78 void thread_hammer_and_kill(shared_and_weak_pools& pools)
  79 {
  80   std::mt19937 urbg;
  81   std::uniform_int_distribution<> dist(0, KILL_ONE_IN - 1);
  82
  83   sp_vector_t::iterator cur_shared = pools.shared_pool.begin();
  84   wp_vector_t::iterator cur_weak = pools.weak_pool.begin();
  85
  86   for (unsigned int i = 0; i < HAMMER_REPEAT; ++i)
  87     {
  88       try
  89       {
  90         sp_A_t strong(*cur_weak);
  91       }
  92       catch (std::bad_weak_ptr& exception)
  93       {
  94         ++cur_weak;
  95         if (cur_weak == pools.weak_pool.end())
  96           break;
  97       }
  98
  99       if (dist(urbg) == 0)
 100       {
 101         cur_shared->reset();
 102         ++cur_shared;
 103       }
 104     }
 105 }
 106
 107 void thread_hammer(wp_vector_t& weak_pool)
 108 {
 109   wp_vector_t::iterator cur_weak = weak_pool.begin();
 110
 111   for (unsigned int i = 0; i < HAMMER_REPEAT; ++i)
 112     {
 113       try
 114       {
 115         sp_A_t strong(*cur_weak);
 116       }
 117       catch (std::bad_weak_ptr& exception)
 118       {
 119         ++cur_weak;
 120         if (cur_weak == weak_pool.end())
 121           break;
 122       }
 123     }
 124 }
 125
 126 void
 127 test01()
 128 {
 129   sp_vector_t obj_pool(POOL_SIZE);
 130
 131   for(auto& obj : obj_pool)
 132     obj.reset(new A);
 133
 134   // Obtain weak references.
 135   std::vector<wp_vector_t> weak_pool(HAMMER_MAX_THREADS, wp_vector_t(obj_pool.begin(), obj_pool.end()));
 136
 137   // Launch threads with pointer to weak reference.
 138   std::thread threads[HAMMER_MAX_THREADS];
 139 #if defined(__sun) && defined(__svr4__) && _XOPEN_VERSION >= 500
 140   pthread_setconcurrency (HAMMER_MAX_THREADS);
 141 #endif
 142
 143   shared_and_weak_pools pools(obj_pool, weak_pool[0]);
 144   threads[0] = std::thread(thread_hammer_and_kill, std::ref(pools));
 145   for (unsigned int worker = 1; worker < HAMMER_MAX_THREADS; worker++)
 146     threads[worker] = std::thread(thread_hammer, std::ref(weak_pool[worker]));
 147
 148   // Wait for threads to complete, then check integrity of reference.
 149   for (auto& thread : threads)
 150     thread.join();
 151
 152   obj_pool.clear();
 153
 154   VERIFY( A::counter == 0 );
 155 }
 156
 157 int
 158 main()
 159 {
 160   test01();
 161   return 0;
 162 }