gdb/testsuite/gdb.threads/multiple-successive-infcall.c

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 2018-2021 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.  */
  26 static pthread_barrier_t print_barrier;
  27
  28 /* Define global thread identifiers.  */
  29 static pthread_t threads[THREADCOUNT];
  30
  31 /* Hold values for each thread at the index supplied to the thread
  32    on creation.  */
  33 static int thread_ids[THREADCOUNT];
  34
  35 /* Find the value associated with the calling thread.  */
  36 static int
  37 get_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.  */
  49 static unsigned long
  50 fast_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.  */
  66 static void *
  67 thread_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
  83 int
  84 main (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 }