Cache the result of pthread_self in low level loops. NFC (#26531)

Author: sbc100

system/lib/libc/musl/src/thread/__timedwait.c

@@ -67,12 +67,13 @@ int __timedwait_cp(volatile int *addr, int val,
 	// cp suffix in the function name means "cancellation point", so this wait can be cancelled
 	// by the users unless current threads cancelability is set to PTHREAD_CANCEL_DISABLE
 	// which may be either done by the user of __timedwait() function.
+	pthread_t self = pthread_self();
 	if (is_runtime_thread ||
-	    pthread_self()->canceldisable != PTHREAD_CANCEL_DISABLE ||
-	    pthread_self()->cancelasync) {
+	    self->canceldisable != PTHREAD_CANCEL_DISABLE ||
+	    self->cancelasync) {
 		double sleepUntilTime = emscripten_get_now() + msecsToSleep;
 		do {
-			if (pthread_self()->cancel) {
+			if (self->cancel) {
 				// The thread was canceled by pthread_cancel().
 				// In the case of cancelasync or PTHREAD_CANCEL_ENABLE we can just call
 				// __pthread_testcancel(), which won't return at all.

system/lib/pthread/emscripten_futex_wait.c

@@ -130,7 +130,8 @@ int emscripten_futex_wait(volatile void *addr, uint32_t val, double max_wait_ms)
   emscripten_conditional_set_current_thread_status(EM_THREAD_STATUS_RUNNING, EM_THREAD_STATUS_WAITFUTEX);
 
 #ifdef __EMSCRIPTEN_PTHREADS__
-  bool cancelable = pthread_self()->cancelasync == PTHREAD_CANCEL_ASYNCHRONOUS;
+  pthread_t self = pthread_self();
+  bool cancelable = self->cancelasync == PTHREAD_CANCEL_ASYNCHRONOUS;
 #else
   bool cancelable = false;
 #endif
@@ -199,19 +200,19 @@ int emscripten_futex_wait(volatile void *addr, uint32_t val, double max_wait_ms)
     // the queue, either from the call here directly after setting `sleeping` to
     // 1, or from another callsite (e.g. the one in `emscripten_yield`).
     if (!is_runtime_thread) {
-      __pthread_self()->sleeping = 1;
+      self->sleeping = 1;
       _emscripten_process_dlopen_queue();
     }
 #endif
     ret = __builtin_wasm_memory_atomic_wait32((int*)addr, val, max_wait_ns);
 #ifdef EMSCRIPTEN_DYNAMIC_LINKING
     if (!is_runtime_thread) {
-      __pthread_self()->sleeping = 0;
+      self->sleeping = 0;
       _emscripten_process_dlopen_queue();
     }
 #endif
 #ifdef __EMSCRIPTEN_PTHREADS__
-    if (cancelable && ret == ATOMICS_WAIT_TIMED_OUT && pthread_self()->cancel) {
+    if (cancelable && ret == ATOMICS_WAIT_TIMED_OUT && self->cancel) {
       // Break out of the loop early if we were cancelled
       break;
     }

test/codesize/test_codesize_minimal_pthreads.json

@@ -1,9 +1,9 @@
 {
   "a.out.js": 7364,
   "a.out.js.gz": 3607,
-  "a.out.nodebug.wasm": 19265,
+  "a.out.nodebug.wasm": 19263,
   "a.out.nodebug.wasm.gz": 8934,
-  "total": 26629,
+  "total": 26627,
   "total_gz": 12541,
   "sent": [
     "a (memory)",

test/codesize/test_codesize_minimal_pthreads_memgrowth.json

@@ -1,9 +1,9 @@
 {
   "a.out.js": 7766,
   "a.out.js.gz": 3812,
-  "a.out.nodebug.wasm": 19266,
+  "a.out.nodebug.wasm": 19264,
   "a.out.nodebug.wasm.gz": 8935,
-  "total": 27032,
+  "total": 27030,
   "total_gz": 12747,
   "sent": [
     "a (memory)",