Reproduce issue #13194 on the Wasm Workers API

See:
#18171 (comment)

Author: kleisauke

.circleci/config.yml

@@ -516,7 +516,7 @@ jobs:
             asan.test_asyncify_longjmp
             asan.test_pthread_run_on_main_thread
             lsan.test_dylink_dso_needed
-            lsan.test_stdio_locking
+            lsan.test_stdio_locking_pthread
             lsan.test_dlfcn_basic
             lsan.test_pthread_create
             lsan.test_pthread_exit_main_stub

test/core/test_stdio_locking.c

@@ -9,12 +9,30 @@
  *   musl/src/stdio/fwrite.c
  */
 #include <assert.h>
-#include <pthread.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
 
+#ifdef __EMSCRIPTEN_PTHREADS__
+#include <pthread.h>
+
 pthread_t thread[2];
+#elif defined(__EMSCRIPTEN_WASM_WORKERS__)
+#include <emscripten/wasm_worker.h>
+#include <emscripten/eventloop.h>
+
+emscripten_wasm_worker_t worker[2];
+#else
+#error Expected to be compiled with either -sWASM_WORKERS or -pthread.
+#endif
+
+#ifndef __wasm_atomics__
+#error Expected to be compiled with -matomics.
+#endif
+
+#ifndef __wasm_bulk_memory__
+#error Expected to be compiled with -mbulk-memory.
+#endif
 
 char *char_repeat(int n, char c) {
   char *dest = malloc(n + 1);
@@ -23,23 +41,31 @@ char *char_repeat(int n, char c) {
   return dest;
 }
 
-void *thread_main(void *arg) {
+void thread_main() {
   char *msg = char_repeat(100, 'a');
   for (int i = 0; i < 10; ++i)
-  printf("%s\n", msg);
+    printf("%s\n", msg);
   free(msg);
-  return 0;
 }
 
+#ifdef __EMSCRIPTEN_WASM_WORKERS__
+void terminate_worker(void *userData)
+{
+  emscripten_terminate_all_wasm_workers();
+  printf("main done\n");
+}
+#endif
+
 int main() {
   printf("in main\n");
+#ifdef __EMSCRIPTEN_PTHREADS__
   void *thread_rtn;
   int rc;
 
-  rc = pthread_create(&thread[0], NULL, thread_main, NULL);
+  rc = pthread_create(&thread[0], NULL, (void* (*)(void*))thread_main, NULL);
   assert(rc == 0);
 
-  rc = pthread_create(&thread[1], NULL, thread_main, NULL);
+  rc = pthread_create(&thread[1], NULL, (void* (*)(void*))thread_main, NULL);
   assert(rc == 0);
 
   rc = pthread_join(thread[0], &thread_rtn);
@@ -51,5 +77,14 @@ int main() {
   assert(thread_rtn == 0);
 
   printf("main done\n");
+#else
+  worker[0] = emscripten_malloc_wasm_worker(/*stack size: */1024);
+  worker[1] = emscripten_malloc_wasm_worker(/*stack size: */1024);
+  emscripten_wasm_worker_post_function_v(worker[0], (void (*))thread_main);
+  emscripten_wasm_worker_post_function_v(worker[1], (void (*))thread_main);
+
+  // Terminate both workers after a small delay
+  emscripten_set_timeout(terminate_worker, 1000, 0);
+#endif
   return 0;
 }

test/test_core.py

@@ -9264,10 +9264,16 @@ def test_emscripten_futexes(self):
     self.do_run_in_out_file_test('core/pthread/emscripten_futexes.c')
 
   @node_pthreads
-  def test_stdio_locking(self):
+  def test_stdio_locking_pthread(self):
     self.set_setting('PTHREAD_POOL_SIZE', '2')
     self.do_run_in_out_file_test('core/test_stdio_locking.c')
 
+  # Cannot use @node_pthreads here, since that links with -pthread
+  def test_stdio_locking_wasm_workers(self):
+    self.set_setting('WASM_WORKERS')
+    self.node_args += shared.node_pthread_flags(self.require_node())
+    self.do_run_in_out_file_test('core/test_stdio_locking.c')
+
   @with_dylink_reversed
   @node_pthreads
   def test_pthread_dylink_basics(self):