| //===-- main.cpp ------------------------------------------------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // This test is intended to create a situation in which a breakpoint will be |
| // hit in two threads at nearly the same moment. The expected result is that |
| // the breakpoint in the second thread will be hit while the breakpoint handler |
| // in the first thread is trying to stop all threads. |
| |
| #include <pthread.h> |
| #include <atomic> |
| |
| // Note that although hogging the CPU while waiting for a variable to change |
| // would be terrible in production code, it's great for testing since it |
| // avoids a lot of messy context switching to get multiple threads synchronized. |
| #define do_nothing() |
| |
| #define pseudo_barrier_wait(bar) \ |
| --bar; \ |
| while (bar > 0) \ |
| do_nothing(); |
| |
| #define pseudo_barrier_init(bar, count) (bar = count) |
| |
| std::atomic_int g_barrier; |
| |
| volatile int g_test = 0; |
| |
| void * |
| thread_func (void *input) |
| { |
| // Wait until both threads are running |
| pseudo_barrier_wait(g_barrier); |
| |
| // Do something |
| g_test++; // Set breakpoint here |
| |
| // Return |
| return NULL; |
| } |
| |
| int main () |
| { |
| pthread_t thread_1; |
| pthread_t thread_2; |
| |
| // Don't let either thread do anything until they're both ready. |
| pseudo_barrier_init(g_barrier, 2); |
| |
| // Create two threads |
| pthread_create (&thread_1, NULL, thread_func, NULL); |
| pthread_create (&thread_2, NULL, thread_func, NULL); |
| |
| // Wait for the threads to finish |
| pthread_join(thread_1, NULL); |
| pthread_join(thread_2, NULL); |
| |
| return 0; |
| } |