Remove loop from emscripten_thread_sleep. NFC

We have code in the lower level emscrpeten_futex_wait that take care
of splitting up the wait for the main runtime thread.  For normal
pthreads I don't see any need to run the message queue while the thread
is sleeping like this.

Instead, it can run from the event loop, or explicitly run.

Followup to emscripten-core#26471

Author: sbc100

system/lib/pthread/library_pthread.c

@@ -65,54 +65,33 @@ int sched_get_priority_min(int policy) {
     return 0;
 }
 
-int pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *restrict attr, int *restrict prioceiling)
-{
+int pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *restrict attr, int *restrict prioceiling) {
   // Not supported either in Emscripten or musl, return a faked value.
   if (prioceiling) *prioceiling = 99;
   return 0;
 }
 
-int pthread_mutexattr_setprioceiling(pthread_mutexattr_t *attr, int prioceiling)
-{
+int pthread_mutexattr_setprioceiling(pthread_mutexattr_t *attr, int prioceiling) {
   // Not supported either in Emscripten or musl, return an error.
   return EPERM;
 }
 
-static uint32_t dummyZeroAddress = 0;
-
 void emscripten_thread_sleep(double msecs) {
-  double now = emscripten_get_now();
-  double target = now + msecs;
-
-  // If we have less than this many msecs left to wait, busy spin that instead.
-  double min_ms_slice_to_sleep = 0.1;
-
-  // Break up sleeping so that we process proxied work at regular intervals.
-  // TODO(sbc): This should be removed and/or moved down into
-  // `emscripten_futex_wait`.
-  double max_ms_slice_to_sleep = 100;
-
-  emscripten_conditional_set_current_thread_status(
-    EM_THREAD_STATUS_RUNNING, EM_THREAD_STATUS_SLEEPING);
-
-  do {
-    // Keep processing the main loop of the calling thread.
-    __pthread_testcancel(); // pthreads spec: sleep is a cancellation point, so must test if this
-                            // thread is cancelled during the sleep.
-    emscripten_current_thread_process_queued_calls();
-
-    now = emscripten_get_now();
-    double ms_to_sleep = target - now;
-    if (ms_to_sleep < min_ms_slice_to_sleep)
-      continue;
-    if (ms_to_sleep > max_ms_slice_to_sleep)
-      ms_to_sleep = max_ms_slice_to_sleep;
-    emscripten_futex_wait(&dummyZeroAddress, 0, ms_to_sleep);
-    now = emscripten_get_now();
-  } while (now < target);
-
-  emscripten_conditional_set_current_thread_status(
-    EM_THREAD_STATUS_SLEEPING, EM_THREAD_STATUS_RUNNING);
+  // We include emscripten_current_thread_process_queued_calls before and
+  // after sleeping since that is how we recieve "async" signals.
+  // We include
+  // We include __pthread_testcancel here becuase clock_nanosleep is
+  // a pthread cancelation point.
+  emscripten_current_thread_process_queued_calls();
+  __pthread_testcancel();
+  emscripten_conditional_set_current_thread_status(EM_THREAD_STATUS_RUNNING,
+                                                   EM_THREAD_STATUS_SLEEPING);
+  uint32_t dummyZeroAddress = 0;
+  emscripten_futex_wait(&dummyZeroAddress, 0, msecs);
+  emscripten_conditional_set_current_thread_status(EM_THREAD_STATUS_SLEEPING,
+                                                   EM_THREAD_STATUS_RUNNING);
+  emscripten_current_thread_process_queued_calls();
+  __pthread_testcancel();
 }
 
 static struct pthread __main_pthread;

system/lib/pthread/library_pthread_stub.c

@@ -231,7 +231,9 @@ int pthread_cancel(pthread_t thread) {
   return 0;
 }
 
-void pthread_testcancel() {}
+void __pthread_testcancel() {}
+
+weak_alias(__pthread_testcancel, pthread_testcancel);
 
 _Noreturn void __pthread_exit(void* status) {
    exit(0);

test/pthread/test_pthread_kill.c

@@ -5,23 +5,26 @@
 
 #include <pthread.h>
 #include <sys/types.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>
 #include <unistd.h>
 #include <errno.h>
 #include <signal.h>
 
+#include <emscripten/console.h>
+
 pthread_cond_t started_cond = PTHREAD_COND_INITIALIZER;
 pthread_mutex_t started_lock = PTHREAD_MUTEX_INITIALIZER;
-_Atomic int got_term_signal = 0;
+_Atomic bool got_term_signal = false;
 
 pthread_t thr;
 
 void signal_handler(int sig, siginfo_t * info, void * arg) {
   printf("signal: %d onthread=%d\n", sig, pthread_self() == thr);
   if (sig == SIGTERM) {
-    got_term_signal = 1;
+    got_term_signal = true;
   }
 }
 
@@ -63,9 +66,9 @@ int main() {
   printf("thread has started, sending SIGTERM\n");
 
   s = pthread_kill(thr, SIGTERM);
+  assert(s == 0);
   printf("SIGTERM sent\n");
 
-  assert(s == 0);
 
   pthread_join(thr, NULL);
   return 0;