glibc/elf/tst-single_threaded-pthread.c

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/* Test support for single-thread optimizations. With threads.
Copyright (C) 2020-2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <stddef.h>
#include <stdio.h>
#include <support/check.h>
#include <support/namespace.h>
#include <support/xdlfcn.h>
#include <support/xthread.h>
#include <sys/single_threaded.h>
/* First barrier synchronizes main thread, thread 1, thread 2. */
static pthread_barrier_t barrier1;
/* Second barrier synchronizes main thread, thread 2. */
static pthread_barrier_t barrier2;
/* Defined in tst-single-threaded-mod1.so. */
_Bool single_threaded_1 (void);
/* Initialized via dlsym. */
static _Bool (*single_threaded_2) (void);
static _Bool (*single_threaded_3) (void);
static _Bool (*single_threaded_4) (void);
static void *
threadfunc (void *closure)
{
TEST_VERIFY (!__libc_single_threaded);
TEST_VERIFY (!single_threaded_1 ());
TEST_VERIFY (!single_threaded_2 ());
/* Wait until the main thread loads more functions. */
xpthread_barrier_wait (&barrier1);
TEST_VERIFY (!__libc_single_threaded);
TEST_VERIFY (!single_threaded_1 ());
TEST_VERIFY (!single_threaded_2 ());
TEST_VERIFY (!single_threaded_3 ());
TEST_VERIFY (!single_threaded_4 ());
/* Second thread waits on second barrier, too. */
if (closure != NULL)
xpthread_barrier_wait (&barrier2);
TEST_VERIFY (!__libc_single_threaded);
TEST_VERIFY (!single_threaded_1 ());
TEST_VERIFY (!single_threaded_2 ());
TEST_VERIFY (!single_threaded_3 ());
TEST_VERIFY (!single_threaded_4 ());
return NULL;
}
/* Used for closure arguments to the subprocess function. */
static char expected_false = 0;
static char expected_true = 1;
/* A subprocess inherits currently inherits the single-threaded state
of the parent process. */
static void
subprocess (void *closure)
{
const char *expected = closure;
TEST_COMPARE (__libc_single_threaded, *expected);
TEST_COMPARE (single_threaded_1 (), *expected);
if (single_threaded_2 != NULL)
TEST_COMPARE (single_threaded_2 (), *expected);
if (single_threaded_3 != NULL)
TEST_COMPARE (single_threaded_3 (), *expected);
if (single_threaded_4 != NULL)
TEST_VERIFY (!single_threaded_4 ());
}
static int
do_test (void)
{
printf ("info: main __libc_single_threaded address: %p\n",
&__libc_single_threaded);
TEST_VERIFY (__libc_single_threaded);
TEST_VERIFY (single_threaded_1 ());
support_isolate_in_subprocess (subprocess, &expected_true);
void *handle_mod2 = xdlopen ("tst-single_threaded-mod2.so", RTLD_LAZY);
single_threaded_2 = xdlsym (handle_mod2, "single_threaded_2");
TEST_VERIFY (single_threaded_2 ());
/* Two threads plus main thread. */
xpthread_barrier_init (&barrier1, NULL, 3);
/* Main thread and second thread. */
xpthread_barrier_init (&barrier2, NULL, 2);
pthread_t thr1 = xpthread_create (NULL, threadfunc, NULL);
TEST_VERIFY (!__libc_single_threaded);
TEST_VERIFY (!single_threaded_1 ());
TEST_VERIFY (!single_threaded_2 ());
support_isolate_in_subprocess (subprocess, &expected_false);
pthread_t thr2 = xpthread_create (NULL, threadfunc, &thr2);
TEST_VERIFY (!__libc_single_threaded);
TEST_VERIFY (!single_threaded_1 ());
TEST_VERIFY (!single_threaded_2 ());
support_isolate_in_subprocess (subprocess, &expected_false);
/* Delayed library load, while already multi-threaded. */
void *handle_mod3 = xdlopen ("tst-single_threaded-mod3.so", RTLD_LAZY);
single_threaded_3 = xdlsym (handle_mod3, "single_threaded_3");
TEST_VERIFY (!__libc_single_threaded);
TEST_VERIFY (!single_threaded_1 ());
TEST_VERIFY (!single_threaded_2 ());
TEST_VERIFY (!single_threaded_3 ());
support_isolate_in_subprocess (subprocess, &expected_false);
/* Same with dlmopen. */
void *handle_mod4 = dlmopen (LM_ID_NEWLM, "tst-single_threaded-mod4.so",
RTLD_LAZY);
single_threaded_4 = xdlsym (handle_mod4, "single_threaded_4");
TEST_VERIFY (!__libc_single_threaded);
TEST_VERIFY (!single_threaded_1 ());
TEST_VERIFY (!single_threaded_2 ());
TEST_VERIFY (!single_threaded_3 ());
TEST_VERIFY (!single_threaded_4 ());
support_isolate_in_subprocess (subprocess, &expected_false);
/* Run the newly loaded functions from the other threads as
well. */
xpthread_barrier_wait (&barrier1);
TEST_VERIFY (!__libc_single_threaded);
TEST_VERIFY (!single_threaded_1 ());
TEST_VERIFY (!single_threaded_2 ());
TEST_VERIFY (!single_threaded_3 ());
TEST_VERIFY (!single_threaded_4 ());
support_isolate_in_subprocess (subprocess, &expected_false);
/* Join first thread. This should not bring us back into
single-threaded mode. */
xpthread_join (thr1);
TEST_VERIFY (!__libc_single_threaded);
TEST_VERIFY (!single_threaded_1 ());
TEST_VERIFY (!single_threaded_2 ());
TEST_VERIFY (!single_threaded_3 ());
TEST_VERIFY (!single_threaded_4 ());
support_isolate_in_subprocess (subprocess, &expected_false);
/* We may be back in single-threaded mode after joining both
threads, but this is not guaranteed. */
xpthread_barrier_wait (&barrier2);
xpthread_join (thr2);
printf ("info: __libc_single_threaded after joining all threads: %d\n",
__libc_single_threaded);
xdlclose (handle_mod4);
xdlclose (handle_mod3);
xdlclose (handle_mod2);
return 0;
}
#include <support/test-driver.c>