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//===-- 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 <atomic>
#include <thread>
// 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 ()
{
// Wait until both threads are running
pseudo_barrier_wait(g_barrier);
// Do something
g_test++; // Set breakpoint here
// Return
return NULL;
}
int main ()
{
// Don't let either thread do anything until they're both ready.
pseudo_barrier_init(g_barrier, 2);
// Create two threads
std::thread thread_1(thread_func);
std::thread thread_2(thread_func);
// Wait for the threads to finish
thread_1.join();
thread_2.join();
return 0;
}
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