1/* This testcase is part of GDB, the GNU debugger.
2
3   Copyright 2018-2023 Free Software Foundation, Inc.
4
5   This program is free software; you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by
7   the Free Software Foundation; either version 3 of the License, or
8   (at your option) any later version.
9
10   This program is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13   GNU General Public License for more details.
14
15   You should have received a copy of the GNU General Public License
16   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
17
18#include <stdio.h>
19#include <stdlib.h>
20#include <pthread.h>
21
22/* This defines the number of threads to spawn.  */
23#define THREADCOUNT 4
24
25/* Global barrier type to control synchronization between threads.  */
26static pthread_barrier_t print_barrier;
27
28/* Define global thread identifiers.  */
29static pthread_t threads[THREADCOUNT];
30
31/* Hold values for each thread at the index supplied to the thread
32   on creation.  */
33static int thread_ids[THREADCOUNT];
34
35/* Find the value associated with the calling thread.  */
36static int
37get_value ()
38{
39  for (int tid = 0; tid < THREADCOUNT; ++tid)
40    {
41      if (pthread_equal (threads[tid], pthread_self ()))
42	return thread_ids[tid];
43    }
44  /* Value for the main thread.  */
45  return 1;
46}
47
48/* Return the nth Fibonacci number.  */
49static unsigned long
50fast_fib (unsigned int n)
51{
52  int a = 0;
53  int b = 1;
54  int t;
55  for (unsigned int i = 0; i < n; ++i)
56    {
57      t = b;
58      b = a + b;
59      a = t;
60    }
61  return a;
62}
63
64/* Encapsulate the synchronization of the threads. Perform a barrier before
65   and after the computation.  */
66static void *
67thread_function (void *args)
68{
69  int tid = *((int *) args);
70  int status = pthread_barrier_wait (&print_barrier);
71  if (status == PTHREAD_BARRIER_SERIAL_THREAD)
72    printf ("All threads entering compute region\n");
73
74  unsigned long result = fast_fib (100); /* testmarker01 */
75  status = pthread_barrier_wait (&print_barrier);
76  if (status == PTHREAD_BARRIER_SERIAL_THREAD)
77    printf ("All threads outputting results\n");
78
79  pthread_barrier_wait (&print_barrier);
80  printf ("Thread %d Result: %lu\n", tid, result);
81}
82
83int
84main (void)
85{
86  int err = pthread_barrier_init (&print_barrier, NULL, THREADCOUNT);
87  if (err != 0)
88    {
89      fprintf (stderr, "Barrier creation failed\n");
90      return EXIT_FAILURE;
91    }
92  /* Create the worker threads (main).  */
93  printf ("Spawning worker threads\n");
94  for (int tid = 0; tid < THREADCOUNT; ++tid)
95    {
96      /* Add 2 so the value maps to the debugger's thread identifiers.  */
97      thread_ids[tid] = tid + 2; /* prethreadcreationmarker */
98      err = pthread_create (&threads[tid], NULL, thread_function,
99			    (void *) &thread_ids[tid]);
100      if (err != 0)
101	{
102	  fprintf (stderr, "Thread creation failed\n");
103	  return EXIT_FAILURE;
104	}
105    }
106  /* Wait for the threads to complete then exit.  */
107  for (int tid = 0; tid < THREADCOUNT; ++tid)
108    pthread_join (threads[tid], NULL);
109
110  return EXIT_SUCCESS;
111}
112