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Use *NSYNC for POSIX threads locking APIs

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Condition variables, barriers, and r/w locks now work very well.
This commit is contained in:
Justine Tunney 2022-09-11 11:02:07 -07:00
parent 3de35e196c
commit b5cb71ab84
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GPG key ID: BE714B4575D6E328
197 changed files with 3734 additions and 3817 deletions
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25
libc/intrin/pthread_once.c
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@ -16,11 +16,12 @@
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/calls/calls.h"
#include "libc/errno.h"
#include "libc/intrin/atomic.h"
#include "libc/intrin/weaken.h"
#include "libc/thread/thread.h"
#include "third_party/nsync/once.h"
#define INIT 0
#define CALLING 1
@ -44,28 +45,30 @@
* @return 0 on success, or errno on error
*/
int pthread_once(pthread_once_t *once, void init(void)) {
char old;
switch ((old = atomic_load_explicit(&once->lock, memory_order_relaxed))) {
uint32_t old;
if (weaken(nsync_run_once)) {
weaken(nsync_run_once)((nsync_once *)once, init);
return 0;
}
switch ((old = atomic_load_explicit(&once->_lock, memory_order_relaxed))) {
case INIT:
if (atomic_compare_exchange_strong_explicit(&once->lock, &old, CALLING,
if (atomic_compare_exchange_strong_explicit(&once->_lock, &old, CALLING,
memory_order_acquire,
memory_order_relaxed)) {
init();
atomic_store(&once->lock, FINISHED);
break;
atomic_store(&once->_lock, FINISHED);
return 0;
}
// fallthrough
case CALLING:
do {
pthread_yield();
} while (atomic_load_explicit(&once->lock, memory_order_relaxed) ==
} while (atomic_load_explicit(&once->_lock, memory_order_relaxed) ==
CALLING);
break;
return 0;
case FINISHED:
break;
return 0;
default:
assert(!"bad once");
return EINVAL;
}
return 0;
}