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 28std::atomic_int g_barrier; 29 30volatile int g_thread_created = 0; 31volatile int g_test = 0; 32 33void * 34step_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 48void * 49create_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 63int 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