• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 two threads are stopped
11 // at a breakpoint and the debugger issues a step-out command.
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_test = 0;
31 
step_out_of_here()32 void step_out_of_here() {
33   g_test += 5; // Set breakpoint here
34 }
35 
36 void *
thread_func(void * input)37 thread_func (void *input)
38 {
39     // Wait until both threads are running
40     pseudo_barrier_wait(g_barrier);
41 
42     // Do something
43     step_out_of_here(); // Expect to stop here after step-out (clang)
44 
45     // Return
46     return NULL;  // Expect to stop here after step-out (icc and gcc)
47 }
48 
main()49 int main ()
50 {
51     pthread_t thread_1;
52     pthread_t thread_2;
53 
54     // Don't let either thread do anything until they're both ready.
55     pseudo_barrier_init(g_barrier, 2);
56 
57     // Create two threads
58     pthread_create (&thread_1, NULL, thread_func, NULL);
59     pthread_create (&thread_2, NULL, thread_func, NULL);
60 
61     // Wait for the threads to finish
62     pthread_join(thread_1, NULL);
63     pthread_join(thread_2, NULL);
64 
65     return 0;
66 }
67