Minor cleanup of setitimer. NFC

These minor cleanups were split out from my larger work on precise
wakeups.

Author: sbc100

system/lib/libc/musl/src/signal/setitimer.c

@@ -6,6 +6,8 @@
 
 #ifdef __EMSCRIPTEN__
 #include <emscripten/emscripten.h>
+#include <emscripten/threading.h>
+#include <assert.h>
 #include <signal.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -63,6 +65,9 @@ void _emscripten_timeout(int which, double now)
 
 void _emscripten_check_timers(double now)
 {
+	// Timers always run on the main runtime thread. They are registered with
+	// _setitimer_js which is proxied to the main runtime thread.
+	assert(emscripten_is_main_runtime_thread());
 	for (int which = 0; which < 3; which++) {
 		if (current_timeout_ms[which]) {
 			// Only call out to JS to get the current time if it was not passed in
@@ -84,14 +89,16 @@ int setitimer(int which, const struct itimerval *restrict new, struct itimerval
 	if (old) {
 		__getitimer(which, old, now);
 	}
+	double timeout_ms = new->it_value.tv_sec * 1000 + new->it_value.tv_usec / 1000.0;
+	double interval_ms = new->it_interval.tv_sec * 1000 + new->it_interval.tv_usec / 1000.0;
 	if (new->it_value.tv_sec || new->it_value.tv_usec) {
-		current_timeout_ms[which] = now + new->it_value.tv_sec * 1000 + new->it_value.tv_usec / 1000;
-		current_intervals_ms[which] = new->it_interval.tv_sec * 1000 + new->it_interval.tv_usec / 1000;
+		current_timeout_ms[which] = now + timeout_ms;
+		current_intervals_ms[which] = interval_ms;
 	} else {
 		current_timeout_ms[which] = 0;
 		current_intervals_ms[which] = 0;
 	}
-	return _setitimer_js(which, new->it_value.tv_sec * 1000 + new->it_value.tv_usec / 1000);
+	return _setitimer_js(which, timeout_ms);
 #else
 	if (sizeof(time_t) > sizeof(long)) {
 		time_t is = new->it_interval.tv_sec, vs = new->it_value.tv_sec;

system/lib/pthread/emscripten_futex_wait.c

@@ -13,6 +13,7 @@
 #include <emscripten/threading.h>
 #include <errno.h>
 #include <math.h>
+#include <stdatomic.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/param.h>
@@ -111,7 +112,7 @@ static int futex_wait_main_browser_thread(volatile void* addr,
     // here and return, it's the same is if what happened on the main thread
     // was the same as calling _emscripten_yield()
     // a few times before calling emscripten_futex_wait().
-    if (__c11_atomic_load((_Atomic uint32_t*)addr, __ATOMIC_SEQ_CST) != val) {
+    if (atomic_load((_Atomic uint32_t*)addr) != val) {
       return -EWOULDBLOCK;
     }
 

system/lib/pthread/emscripten_yield.c

@@ -20,14 +20,12 @@ static void dummy(double now)
 weak_alias(dummy, _emscripten_check_timers);
 
 void _emscripten_yield(double now) {
-  int is_runtime_thread = emscripten_is_main_runtime_thread();
-
   // When a secondary thread crashes, we need to be able to interrupt the main
   // thread even if it's in a blocking/looping on a mutex.  We want to avoid
   // using the normal proxying mechanism to send this message since it can
   // allocate (or otherwise itself crash) so use a low level atomic primitive
   // for this signal.
-  if (is_runtime_thread) {
+  if (emscripten_is_main_runtime_thread()) {
     if (crashed_thread_id) {
       // Mark the crashed thread as strongly referenced so that Node.js doesn't
       // exit while the pthread is propagating the uncaught exception back to

test/codesize/test_codesize_hello_dylink_all.json

@@ -1,7 +1,7 @@
 {
   "a.out.js": 244343,
-  "a.out.nodebug.wasm": 577447,
-  "total": 821790,
+  "a.out.nodebug.wasm": 577432,
+  "total": 821775,
   "sent": [
     "IMG_Init",
     "IMG_Load",