elf/tst-single_threaded-pthread-static.c

   1 /* Test support for single-thread optimizations.  With threads, static version.
   2    Copyright (C) 2020-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 /* This test is a stripped-down version of
  20    tst-single_threaded-pthread.c, without any loading of dynamic
  21    objects.  */
  22
  23 #include <stdio.h>
  24 #include <support/check.h>
  25 #include <support/xthread.h>
  26 #include <sys/single_threaded.h>
  27
  28 /* First barrier synchronizes main thread, thread 1, thread 2.  */
  29 static pthread_barrier_t barrier1;
  30
  31 /* Second barrier synchronizes main thread, thread 2.  */
  32 static pthread_barrier_t barrier2;
  33
  34 static void *
  35 threadfunc (void *closure)
  36 {
  37   TEST_VERIFY (!__libc_single_threaded);
  38
  39   /* Wait for the main thread and the other thread.  */
  40   xpthread_barrier_wait (&barrier1);
  41   TEST_VERIFY (!__libc_single_threaded);
  42
  43   /* Second thread waits on second barrier, too.  */
  44   if (closure != NULL)
  45     xpthread_barrier_wait (&barrier2);
  46   TEST_VERIFY (!__libc_single_threaded);
  47
  48   return NULL;
  49 }
  50
  51 static int
  52 do_test (void)
  53 {
  54   TEST_VERIFY (__libc_single_threaded);
  55
  56   /* Two threads plus main thread.  */
  57   xpthread_barrier_init (&barrier1, NULL, 3);
  58
  59   /* Main thread and second thread.  */
  60   xpthread_barrier_init (&barrier2, NULL, 2);
  61
  62   pthread_t thr1 = xpthread_create (NULL, threadfunc, NULL);
  63   TEST_VERIFY (!__libc_single_threaded);
  64
  65   pthread_t thr2 = xpthread_create (NULL, threadfunc, &thr2);
  66   TEST_VERIFY (!__libc_single_threaded);
  67
  68   xpthread_barrier_wait (&barrier1);
  69   TEST_VERIFY (!__libc_single_threaded);
  70
  71   /* Join first thread.  This should not bring us back into
  72      single-threaded mode.  */
  73   xpthread_join (thr1);
  74   TEST_VERIFY (!__libc_single_threaded);
  75
  76   /* We may be back in single-threaded mode after joining both
  77      threads, but this is not guaranteed.  */
  78   xpthread_barrier_wait (&barrier2);
  79   xpthread_join (thr2);
  80   printf ("info: __libc_single_threaded after joining all threads: %d\n",
  81           __libc_single_threaded);
  82
  83   return 0;
  84 }
  85
  86 #include <support/test-driver.c>