Add emscripten_thread_set_strongref() to the public API

src/library_pthread.js

@@ -188,11 +188,11 @@ var LibraryPThread = {
       // worker pool as an unused worker.
       worker.pthread_ptr = 0;
 
-#if ENVIRONMENT_MAY_BE_NODE && PROXY_TO_PTHREAD
+#if ENVIRONMENT_MAY_BE_NODE
       if (ENVIRONMENT_IS_NODE) {
-        // Once the proxied main thread has finished, mark it as weakly
-        // referenced so that its existence does not prevent Node.js from
-        // exiting.  This has no effect if the worker is already weakly
+        // Once a pthread has finished and the worker becomes idle, mark it
+        // as weakly referenced so that its existence does not prevent Node.js
+        // from exiting.  This has no effect if the worker is already weakly
         // referenced.
         worker.unref();
       }
@@ -526,9 +526,9 @@ var LibraryPThread = {
     else postMessage({ cmd: 'cleanupThread', thread });
   },
 
-  _emscripten_thread_set_strongref: (thread) => {
+  emscripten_thread_set_strongref: (thread) => {
     // Called when a thread needs to be strongly referenced.
-    // Currently only used for:
+    // Internally used for:
     // - keeping the "main" thread alive in PROXY_TO_PTHREAD mode;
     // - crashed threads that needs to propagate the uncaught exception
     //   back to the main thread.

src/library_sigs.js

@@ -333,7 +333,6 @@ sigs = {
   _emscripten_thread_cleanup__sig: 'vp',
   _emscripten_thread_exit_joinable__sig: 'vp',
   _emscripten_thread_mailbox_await__sig: 'vp',
-  _emscripten_thread_set_strongref__sig: 'vp',
   _emscripten_throw_longjmp__sig: 'v',
   _emval_as__sig: 'dppp',
   _emval_as_int64__sig: 'jpp',
@@ -813,6 +812,7 @@ sigs = {
   emscripten_supports_offscreencanvas__sig: 'i',
   emscripten_terminate_all_wasm_workers__sig: 'v',
   emscripten_terminate_wasm_worker__sig: 'vi',
+  emscripten_thread_set_strongref__sig: 'vp',
   emscripten_throw_number__sig: 'vd',
   emscripten_throw_string__sig: 'vp',
   emscripten_trace_annotate_address_type__sig: 'vpp',

system/include/emscripten/threading.h

@@ -77,6 +77,15 @@ pthread_t emscripten_main_runtime_thread_id(void);
 //         Asyncify builds.
 void emscripten_thread_sleep(double msecs);
 
+// Marks the given thread as strongly referenced. This is used to prevent the
+// Node.js application from exiting as long as there are strongly referenced
+// threads still running. Normally you don't need to call this function, and
+// the pthread behaviour will match native in that background threads won't
+// keep runtime alive, but waiting for them via e.g. pthread_join will.
+// However, this is useful for features like PROXY_TO_PTHREAD where we want to
+// keep running as long as the detached pthread is.
+void emscripten_thread_set_strongref(pthread_t thread);
+
 // Sets the name of the given thread. Pass pthread_self() as the thread ID to
 // set the name of the calling thread.
 // The name parameter is a UTF-8 encoded string which is truncated to 32 bytes.

system/lib/libc/crt1_proxy_main.c

@@ -13,8 +13,6 @@
 #include <emscripten/threading.h>
 #include <emscripten/eventloop.h>
 
-#include "threading_internal.h"
-
 static int _main_argc;
 static char** _main_argv;
 
@@ -54,7 +52,7 @@ EMSCRIPTEN_KEEPALIVE int _emscripten_proxy_main(int argc, char** argv) {
   if (rc == 0) {
     // Mark the thread as strongly referenced, so that Node.js doesn't exit
     // while the pthread is running.
-    _emscripten_thread_set_strongref(thread);
+    emscripten_thread_set_strongref(thread);
   }
   return rc;
 }

system/lib/pthread/emscripten_yield.c

@@ -32,7 +32,7 @@ void _emscripten_yield(double now) {
       // Mark the crashed thread as strongly referenced so that Node.js doesn't
       // exit while the pthread is propagating the uncaught exception back to
       // the main thread.
-      _emscripten_thread_set_strongref(crashed_thread_id);
+      emscripten_thread_set_strongref(crashed_thread_id);
       // Return the event loop so we can handle the message from the crashed
       // thread.
       emscripten_exit_with_live_runtime();

system/lib/pthread/threading_internal.h

@@ -50,15 +50,6 @@ void _emscripten_thread_cleanup(pthread_t thread);
 hidden void* _emscripten_tls_init(void);
 hidden void _emscripten_tls_free(void);
 
-// Marks the given thread as strongly referenced. This is used to prevent the
-// Node.js application from exiting as long as there are strongly referenced
-// threads still running. Normally you don't need to call this function, and
-// the pthread behaviour will match native in that background threads won't
-// keep runtime alive, but waiting for them via e.g. pthread_join will. 
-// However, this is useful for features like PROXY_TO_PTHREAD where we want to
-// keep running as long as the detached pthread is.
-void _emscripten_thread_set_strongref(pthread_t thread);
-
 // Checks certain structural invariants.  This allows us to detect when
 // already-freed threads are used in some APIs.  Technically this is undefined
 // behaviour, but we have a couple of places where we add these checks so that

test/other/codesize/test_codesize_minimal_pthreads.gzsize

@@ -1 +1 @@
-4163
+4170

test/other/codesize/test_codesize_minimal_pthreads.imports

@@ -1,7 +1,7 @@
 a (memory)
 b (emscripten_get_now)
 c (exit)
-d (_emscripten_thread_set_strongref)
+d (emscripten_thread_set_strongref)
 e (fd_write)
 f (emscripten_runtime_keepalive_check)
 g (emscripten_resize_heap)

test/other/codesize/test_codesize_minimal_pthreads.sent

@@ -1,7 +1,7 @@
 a (memory)
 b (emscripten_get_now)
 c (exit)
-d (_emscripten_thread_set_strongref)
+d (emscripten_thread_set_strongref)
 e (fd_write)
 f (emscripten_runtime_keepalive_check)
 g (emscripten_resize_heap)