elf/tst-single_threaded-pthread.c

   1 /* Test support for single-thread optimizations.  With threads.
   2    Copyright (C) 2020-2024 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 #include <stddef.h>
  20 #include <stdio.h>
  21 #include <support/check.h>
  22 #include <support/namespace.h>
  23 #include <support/xdlfcn.h>
  24 #include <support/xthread.h>
  25 #include <sys/single_threaded.h>
  26
  27 /* First barrier synchronizes main thread, thread 1, thread 2.  */
  28 static pthread_barrier_t barrier1;
  29
  30 /* Second barrier synchronizes main thread, thread 2.  */
  31 static pthread_barrier_t barrier2;
  32
  33 /* Defined in tst-single-threaded-mod1.so.  */
  34 _Bool single_threaded_1 (void);
  35
  36 /* Initialized via dlsym.  */
  37 static _Bool (*single_threaded_2) (void);
  38 static _Bool (*single_threaded_3) (void);
  39 static _Bool (*single_threaded_4) (void);
  40
  41 static void *
  42 threadfunc (void *closure)
  43 {
  44   TEST_VERIFY (!__libc_single_threaded);
  45   TEST_VERIFY (!single_threaded_1 ());
  46   TEST_VERIFY (!single_threaded_2 ());
  47
  48   /* Wait until the main thread loads more functions.  */
  49   xpthread_barrier_wait (&barrier1);
  50
  51   TEST_VERIFY (!__libc_single_threaded);
  52   TEST_VERIFY (!single_threaded_1 ());
  53   TEST_VERIFY (!single_threaded_2 ());
  54   TEST_VERIFY (!single_threaded_3 ());
  55   TEST_VERIFY (!single_threaded_4 ());
  56
  57   /* Second thread waits on second barrier, too.  */
  58   if (closure != NULL)
  59     xpthread_barrier_wait (&barrier2);
  60   TEST_VERIFY (!__libc_single_threaded);
  61   TEST_VERIFY (!single_threaded_1 ());
  62   TEST_VERIFY (!single_threaded_2 ());
  63   TEST_VERIFY (!single_threaded_3 ());
  64   TEST_VERIFY (!single_threaded_4 ());
  65
  66   return NULL;
  67 }
  68
  69 /* Used for closure arguments to the subprocess function.  */
  70 static char expected_false = 0;
  71 static char expected_true = 1;
  72
  73 /* A subprocess inherits currently inherits the single-threaded state
  74    of the parent process.  */
  75 static void
  76 subprocess (void *closure)
  77 {
  78   const char *expected = closure;
  79   TEST_COMPARE (__libc_single_threaded, *expected);
  80   TEST_COMPARE (single_threaded_1 (), *expected);
  81   if (single_threaded_2 != NULL)
  82     TEST_COMPARE (single_threaded_2 (), *expected);
  83   if (single_threaded_3 != NULL)
  84     TEST_COMPARE (single_threaded_3 (), *expected);
  85   if (single_threaded_4 != NULL)
  86     TEST_VERIFY (!single_threaded_4 ());
  87 }
  88
  89 static int
  90 do_test (void)
  91 {
  92   printf ("info: main __libc_single_threaded address: %p\n",
  93           &__libc_single_threaded);
  94   TEST_VERIFY (__libc_single_threaded);
  95   TEST_VERIFY (single_threaded_1 ());
  96   support_isolate_in_subprocess (subprocess, &expected_true);
  97
  98   void *handle_mod2 = xdlopen ("tst-single_threaded-mod2.so", RTLD_LAZY);
  99   single_threaded_2 = xdlsym (handle_mod2, "single_threaded_2");
 100   TEST_VERIFY (single_threaded_2 ());
 101
 102   /* Two threads plus main thread.  */
 103   xpthread_barrier_init (&barrier1, NULL, 3);
 104
 105   /* Main thread and second thread.  */
 106   xpthread_barrier_init (&barrier2, NULL, 2);
 107
 108   pthread_t thr1 = xpthread_create (NULL, threadfunc, NULL);
 109   TEST_VERIFY (!__libc_single_threaded);
 110   TEST_VERIFY (!single_threaded_1 ());
 111   TEST_VERIFY (!single_threaded_2 ());
 112   support_isolate_in_subprocess (subprocess, &expected_false);
 113
 114   pthread_t thr2 = xpthread_create (NULL, threadfunc, &thr2);
 115   TEST_VERIFY (!__libc_single_threaded);
 116   TEST_VERIFY (!single_threaded_1 ());
 117   TEST_VERIFY (!single_threaded_2 ());
 118   support_isolate_in_subprocess (subprocess, &expected_false);
 119
 120   /* Delayed library load, while already multi-threaded.  */
 121   void *handle_mod3 = xdlopen ("tst-single_threaded-mod3.so", RTLD_LAZY);
 122   single_threaded_3 = xdlsym (handle_mod3, "single_threaded_3");
 123   TEST_VERIFY (!__libc_single_threaded);
 124   TEST_VERIFY (!single_threaded_1 ());
 125   TEST_VERIFY (!single_threaded_2 ());
 126   TEST_VERIFY (!single_threaded_3 ());
 127   support_isolate_in_subprocess (subprocess, &expected_false);
 128
 129   /* Same with dlmopen.  */
 130   void *handle_mod4 = dlmopen (LM_ID_NEWLM, "tst-single_threaded-mod4.so",
 131                                RTLD_LAZY);
 132   single_threaded_4 = xdlsym (handle_mod4, "single_threaded_4");
 133   TEST_VERIFY (!__libc_single_threaded);
 134   TEST_VERIFY (!single_threaded_1 ());
 135   TEST_VERIFY (!single_threaded_2 ());
 136   TEST_VERIFY (!single_threaded_3 ());
 137   TEST_VERIFY (!single_threaded_4 ());
 138   support_isolate_in_subprocess (subprocess, &expected_false);
 139
 140   /* Run the newly loaded functions from the other threads as
 141      well.  */
 142   xpthread_barrier_wait (&barrier1);
 143   TEST_VERIFY (!__libc_single_threaded);
 144   TEST_VERIFY (!single_threaded_1 ());
 145   TEST_VERIFY (!single_threaded_2 ());
 146   TEST_VERIFY (!single_threaded_3 ());
 147   TEST_VERIFY (!single_threaded_4 ());
 148   support_isolate_in_subprocess (subprocess, &expected_false);
 149
 150   /* Join first thread.  This should not bring us back into
 151      single-threaded mode.  */
 152   xpthread_join (thr1);
 153   TEST_VERIFY (!__libc_single_threaded);
 154   TEST_VERIFY (!single_threaded_1 ());
 155   TEST_VERIFY (!single_threaded_2 ());
 156   TEST_VERIFY (!single_threaded_3 ());
 157   TEST_VERIFY (!single_threaded_4 ());
 158   support_isolate_in_subprocess (subprocess, &expected_false);
 159
 160   /* We may be back in single-threaded mode after joining both
 161      threads, but this is not guaranteed.  */
 162   xpthread_barrier_wait (&barrier2);
 163   xpthread_join (thr2);
 164   printf ("info: __libc_single_threaded after joining all threads: %d\n",
 165           __libc_single_threaded);
 166
 167   xdlclose (handle_mod4);
 168   xdlclose (handle_mod3);
 169   xdlclose (handle_mod2);
 170
 171   return 0;
 172 }
 173
 174 #include <support/test-driver.c>