lldb/test/API/python_api/watchpoint/watchlocation/main.cpp

   1 #include <chrono>
   2 #include <condition_variable>
   3 #include <cstdio>
   4 #include <random>
   5 #include <thread>
   6
   7 std::default_random_engine g_random_engine{std::random_device{}()};
   8 std::uniform_int_distribution<> g_distribution{0, 3000000};
   9 std::condition_variable g_condition_variable;
  10 std::mutex g_mutex;
  11 int g_count;
  12
  13 char *g_char_ptr = nullptr;
  14
  15 void
  16 barrier_wait()
  17 {
  18     std::unique_lock<std::mutex> lock{g_mutex};
  19     if (--g_count > 0)
  20         g_condition_variable.wait(lock);
  21     else
  22         g_condition_variable.notify_all();
  23 }
  24
  25 void
  26 do_bad_thing_with_location(char *char_ptr, char new_val)
  27 {
  28     *char_ptr = new_val;
  29 }
  30
  31 uint32_t
  32 access_pool (bool flag = false)
  33 {
  34     static std::mutex g_access_mutex;
  35     if (!flag)
  36         g_access_mutex.lock();
  37
  38     char old_val = *g_char_ptr;
  39     if (flag)
  40         do_bad_thing_with_location(g_char_ptr, old_val + 1);
  41
  42     if (!flag)
  43         g_access_mutex.unlock();
  44     return *g_char_ptr;
  45 }
  46
  47 void
  48 thread_func (uint32_t thread_index)
  49 {
  50     printf ("%s (thread index = %u) startng...\n", __FUNCTION__, thread_index);
  51
  52     barrier_wait();
  53
  54     uint32_t count = 0;
  55     uint32_t val;
  56     while (count++ < 15)
  57     {
  58         // random micro second sleep from zero to 3 seconds
  59         int usec = g_distribution(g_random_engine);
  60         printf ("%s (thread = %u) doing a usleep (%d)...\n", __FUNCTION__, thread_index, usec);
  61         std::this_thread::sleep_for(std::chrono::microseconds{usec});
  62
  63         if (count < 7)
  64             val = access_pool ();
  65         else
  66             val = access_pool (true);
  67
  68         printf ("%s (thread = %u) after usleep access_pool returns %d (count=%d)...\n", __FUNCTION__, thread_index, val, count);
  69     }
  70     printf ("%s (thread index = %u) exiting...\n", __FUNCTION__, thread_index);
  71 }
  72
  73
  74 int main (int argc, char const *argv[])
  75 {
  76     g_count = 4;
  77     std::thread threads[3];
  78
  79     g_char_ptr = new char{};
  80
  81     // Create 3 threads
  82     for (auto &thread : threads)
  83         thread = std::thread{thread_func, std::distance(threads, &thread)};
  84
  85     printf ("Before turning all three threads loose...\n"); // Set break point at this line.
  86     barrier_wait();
  87
  88     // Join all of our threads
  89     for (auto &thread : threads)
  90         thread.join();
  91
  92     delete g_char_ptr;
  93
  94     return 0;
  95 }