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

   1 // Copyright (C) 2006-2021 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-additional-options "-pthread" { target pthread } }
  22 // { dg-add-options libatomic }
  23 // { dg-require-effective-target c++11 }
  24 // { dg-require-gthreads "" }
  25 // { dg-require-cstdint "" }
  26
  27 #include <memory>
  28 #include <random>
  29 #include <vector>
  30 #include <iostream>
  31 #include <cstdlib>
  32 #include <thread>
  33 #include <atomic>
  34 #include <functional>
  35 #include <testsuite_hooks.h>
  36
  37 #ifdef _GLIBCXX_HAVE_UNISTD_H
  38 #include <unistd.h>     // To test for _POSIX_THREAD_PRIORITY_SCHEDULING
  39 #endif
  40
  41 /* This (brute-force) tests the atomicity and thus thread safety of the
  42  * shared_ptr <- weak_ptr
  43  * assignment operation by allocating a test object, retrieving a weak
  44  * reference to it, and letting a number of threads repeatedly create strong
  45  * references from the weak reference.
  46  * Specifically, this tests the function _Sp_counted_base<true>::add_ref_lock()
  47  */
  48
  49
  50 const unsigned int HAMMER_MAX_THREADS = 10;
  51 const unsigned int POOL_SIZE = 1000;
  52 const unsigned long HAMMER_REPEAT = 100000;
  53 const unsigned long KILL_ONE_IN = 1000;
  54
  55 struct A
  56 {
  57   static std::atomic<int> counter;
  58   A() { counter.fetch_add(1, std::memory_order_relaxed); }
  59  ~A() { counter.fetch_sub(1, std::memory_order_relaxed); }
  60 };
  61
  62 std::atomic<int> A::counter{ 0 };
  63
  64 typedef std::shared_ptr<A> sp_A_t;
  65 typedef std::weak_ptr<A> wp_A_t;
  66
  67 typedef std::vector<sp_A_t> sp_vector_t;
  68 typedef std::vector<wp_A_t> wp_vector_t;
  69
  70 struct shared_and_weak_pools
  71 {
  72   sp_vector_t& shared_pool;
  73   wp_vector_t& weak_pool;
  74
  75   shared_and_weak_pools(sp_vector_t& _shared_pool, wp_vector_t& _weak_pool)
  76     : shared_pool(_shared_pool), weak_pool(_weak_pool)
  77     { }
  78 };
  79
  80 void thread_hammer_and_kill(shared_and_weak_pools& pools)
  81 {
  82   std::mt19937 urbg;
  83   std::uniform_int_distribution<> dist(0, KILL_ONE_IN - 1);
  84
  85   sp_vector_t::iterator cur_shared = pools.shared_pool.begin();
  86   wp_vector_t::iterator cur_weak = pools.weak_pool.begin();
  87
  88   for (unsigned int i = 0; i < HAMMER_REPEAT; ++i)
  89     {
  90       try
  91       {
  92         sp_A_t strong(*cur_weak);
  93       }
  94       catch (std::bad_weak_ptr& exception)
  95       {
  96         ++cur_weak;
  97         if (cur_weak == pools.weak_pool.end())
  98           break;
  99       }
 100
 101       if (dist(urbg) == 0)
 102       {
 103         cur_shared->reset();
 104         ++cur_shared;
 105       }
 106     }
 107 }
 108
 109 void thread_hammer(wp_vector_t& weak_pool)
 110 {
 111   wp_vector_t::iterator cur_weak = weak_pool.begin();
 112
 113   for (unsigned int i = 0; i < HAMMER_REPEAT; ++i)
 114     {
 115       try
 116       {
 117         sp_A_t strong(*cur_weak);
 118       }
 119       catch (std::bad_weak_ptr& exception)
 120       {
 121         ++cur_weak;
 122         if (cur_weak == weak_pool.end())
 123           break;
 124       }
 125     }
 126 }
 127
 128 void
 129 test01()
 130 {
 131   sp_vector_t obj_pool(POOL_SIZE);
 132
 133   for(auto& obj : obj_pool)
 134     obj.reset(new A);
 135
 136   // Obtain weak references.
 137   std::vector<wp_vector_t> weak_pool(HAMMER_MAX_THREADS, wp_vector_t(obj_pool.begin(), obj_pool.end()));
 138
 139   // Launch threads with pointer to weak reference.
 140   std::thread threads[HAMMER_MAX_THREADS];
 141 #if defined(__sun) && defined(__svr4__) && _XOPEN_VERSION >= 500
 142   pthread_setconcurrency (HAMMER_MAX_THREADS);
 143 #endif
 144
 145   shared_and_weak_pools pools(obj_pool, weak_pool[0]);
 146   threads[0] = std::thread(thread_hammer_and_kill, std::ref(pools));
 147   for (unsigned int worker = 1; worker < HAMMER_MAX_THREADS; worker++)
 148     threads[worker] = std::thread(thread_hammer, std::ref(weak_pool[worker]));
 149
 150   // Wait for threads to complete, then check integrity of reference.
 151   for (auto& thread : threads)
 152     thread.join();
 153
 154   obj_pool.clear();
 155
 156   VERIFY( A::counter == 0 );
 157 }
 158
 159 int
 160 main()
 161 {
 162   test01();
 163   return 0;
 164 }