Use emscripten_has_threading_support. NFC (#22709)

This change also fixes a bug in `LIBRARY_DEBUG` where it wasn't handling
single line arrow function correctly.

Author: sbc100

src/jsifier.mjs

@@ -284,17 +284,21 @@ ${argConversions}
 
     // apply LIBRARY_DEBUG if relevant
     if (LIBRARY_DEBUG && !isJsOnlySymbol(symbol)) {
-      snippet = modifyJSFunction(
-        snippet,
-        (args, body, async) => `\
+      snippet = modifyJSFunction(snippet, (args, body, async, oneliner) => {
+        var run_func;
+        if (oneliner) {
+          run_func = `var ret = ${body}`;
+        } else {
+          run_func = `var ret = (() => { ${body} })();`;
+        }
+        return `\
 function(${args}) {
-  var ret = (() => { if (runtimeDebug) err("[library call:${mangled}: " + Array.prototype.slice.call(arguments).map(prettyPrint) + "]");
-  ${body}
-  })();
-  if (runtimeDebug && typeof ret != "undefined") err("  [     return:" + prettyPrint(ret));
+  if (runtimeDebug) err("[library call:${mangled}: " + Array.prototype.slice.call(arguments).map(prettyPrint) + "]");
+  ${run_func}
+  if (runtimeDebug) err("  [     return:" + prettyPrint(ret));
   return ret;
-}`,
-      );
+}`;
+      });
     }
 
     const sig = LibraryManager.library[symbol + '__sig'];

src/library_pthread.js

@@ -690,13 +690,16 @@ var LibraryPThread = {
   __pthread_create_js__noleakcheck: true,
 #endif
   __pthread_create_js__deps: ['$spawnThread', 'pthread_self', '$pthreadCreateProxied',
+    'emscripten_has_threading_support',
 #if OFFSCREENCANVAS_SUPPORT
     'malloc',
 #endif
   ],
   __pthread_create_js: (pthread_ptr, attr, startRoutine, arg) => {
-    if (typeof SharedArrayBuffer == 'undefined') {
-      err('Current environment does not support SharedArrayBuffer, pthreads are not available!');
+    if (!_emscripten_has_threading_support()) {
+#if ASSERTIONS
+      dbg('pthread_create: environment does not support SharedArrayBuffer, pthreads are not available');
+#endif
       return {{{ cDefs.EAGAIN }}};
     }
 #if PTHREADS_DEBUG

src/runtime_debug.js

@@ -171,7 +171,7 @@ var runtimeDebug = true; // Switch to false at runtime to disable logging at the
 var printObjectList = [];
 
 function prettyPrint(arg) {
-  if (typeof arg == 'undefined') return '!UNDEFINED!';
+  if (typeof arg == 'undefined') return 'undefined';
   if (typeof arg == 'boolean') arg = arg + 0;
   if (!arg) return arg;
   var index = printObjectList.indexOf(arg);

test/other/codesize/test_codesize_minimal_pthreads.gzsize

@@ -1 +1 @@
-4951
+4911

test/other/codesize/test_codesize_minimal_pthreads.jssize

@@ -1 +1 @@
-10465
+10376

test/test_browser.py

@@ -3847,11 +3847,12 @@ def test_pthread_condition_variable(self):
 
   # Test that pthreads are able to do printf.
   @parameterized({
-    '': (False,),
-    'debug': (True,),
+    '': ([],),
+    'O3': (['-O3'],),
+    'debug': (['-sLIBRARY_DEBUG'],),
   })
-  def test_pthread_printf(self, debug):
-     self.btest_exit('pthread/test_pthread_printf.c', args=['-O3', '-pthread', '-sPTHREAD_POOL_SIZE', '-sLIBRARY_DEBUG=%d' % debug])
+  def test_pthread_printf(self, args):
+     self.btest_exit('pthread/test_pthread_printf.c', args=['-pthread', '-sPTHREAD_POOL_SIZE'] + args)
 
   # Test that pthreads are able to do cout. Failed due to https://bugzilla.mozilla.org/show_bug.cgi?id=1154858.
   def test_pthread_iostream(self):