1 //===-- main.cpp ------------------------------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 // This test is intended to create a situation in which one thread will be 11 // created while a the debugger is stepping in another thread. 12 13 #include <pthread.h> 14 #include <atomic> 15 16 // Note that although hogging the CPU while waiting for a variable to change 17 // would be terrible in production code, it's great for testing since it 18 // avoids a lot of messy context switching to get multiple threads synchronized. 19 #define do_nothing() 20 21 #define pseudo_barrier_wait(bar) \ 22 --bar; \ 23 while (bar > 0) \ 24 do_nothing(); 25 26 #define pseudo_barrier_init(bar, count) (bar = count) 27 28 std::atomic_int g_barrier; 29 30 volatile int g_thread_created = 0; 31 volatile int g_test = 0; 32 33 void * 34 step_thread_func (void *input) 35 { 36 g_test = 0; // Set breakpoint here 37 38 while (!g_thread_created) 39 g_test++; 40 41 // One more time to provide a continue point 42 g_test++; // Continue from here 43 44 // Return 45 return NULL; 46 } 47 48 void * 49 create_thread_func (void *input) 50 { 51 pthread_t *step_thread = (pthread_t*)input; 52 53 // Wait until the main thread knows this thread is started. 54 pseudo_barrier_wait(g_barrier); 55 56 // Wait until the other thread is done. 57 pthread_join(*step_thread, NULL); 58 59 // Return 60 return NULL; 61 } 62 63 int main () 64 { 65 pthread_t thread_1; 66 pthread_t thread_2; 67 68 // Use a simple count to simulate a barrier. 69 pseudo_barrier_init(g_barrier, 2); 70 71 // Create a thread to hit the breakpoint. 72 pthread_create (&thread_1, NULL, step_thread_func, NULL); 73 74 // Wait until the step thread is stepping 75 while (g_test < 1) 76 do_nothing(); 77 78 // Create a thread to exit while we're stepping. 79 pthread_create (&thread_2, NULL, create_thread_func, &thread_1); 80 81 // Wait until that thread is started 82 pseudo_barrier_wait(g_barrier); 83 84 // Let the stepping thread know the other thread is there 85 g_thread_created = 1; 86 87 // Wait for the threads to finish. 88 pthread_join(thread_2, NULL); 89 pthread_join(thread_1, NULL); 90 91 return 0; 92 } 93
