forked from Imagelibrary/binutils-gdb
75b2eb97a4
I noticed that sometimes the value returned by $_inferior_thread_count can become out of sync with the actual thread count of the inferior, and will disagree with the number of threads reported by 'info threads'. This commit fixes this issue. The cause of the problem is that 'info threads' includes a call to update_thread_list, this can be seen in print_thread_info_1 in thread.c, while $_inferior_thread_count doesn't include a similar call, see the function inferior_thread_count_make_value also in thread.c. Of course, this is only a problem when GDB is running on a target that relies on update_thread_list calls to learn about new threads, e.g. remote or extended-remote targets. Native targets generally learn about new threads as soon as they appear and will not have this problem. I ran into this issue when writing a test for the next commit which uses inferior function calls to add an remove threads from an inferior. But for testing I've made use of non-stop mode and asynchronous inferior execution; by reading the inferior state I can know when a new thread has been created, at which point I can print $_inferior_thread_count while the inferior is still running. This is important, if I stop the inferior then GDB will pass through an update_thread_list call in the normal stop code, which will synchronise the thread list, after which $_inferior_thread_count will report the correct value. With this change in place $_inferior_thread_count is now correct.
81 lines
1.8 KiB
C
81 lines
1.8 KiB
C
/* This testcase is part of GDB, the GNU debugger.
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Copyright 2023 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include <pthread.h>
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#include <assert.h>
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#include <unistd.h>
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/* Set to 0 by GDB to cause the inferior to drop out of a spin loop. */
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volatile int spin = 1;
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/* Set by the inferior to communicate to GDB what stage of the test we are
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in. Initially 0, but set to 1 once a new thread has been created. Then
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set to 2 once the extra thread has exited. */
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volatile int stage = 0;
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/* New thread worker function. Just spins until GDB tells it to exit. */
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void *
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thread_func (void *arg)
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{
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assert (arg == NULL);
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stage = 1;
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while (spin)
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sleep (1);
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return NULL;
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}
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/* Somewhere to place a breakpoint. */
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void
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breakpt ()
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{
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/* Nothing. */
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}
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/* Create a new test that spins until GDB tells it to exit. Then, once the
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new thread has exited, this thread spins until GDB tells us to exit. */
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int
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main ()
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{
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alarm (600);
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breakpt ();
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pthread_t thr;
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int res;
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res = pthread_create (&thr, NULL, thread_func, NULL);
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assert (res == 0);
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void *retval;
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res = pthread_join (thr, &retval);
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assert (res == 0);
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spin = 1;
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stage = 2;
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while (spin)
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sleep (1);
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breakpt ();
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return 0;
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}
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