Avoid calling process.exit under node (#18754)

Instead we always prefer to let exceptions bubble out and get handles by
whatever handlers are installed.

Doing this did exposed a few places where we were calling back into
the runtime after it had exited.  This was previously being masked by
the fact that we were bringing down the entire node process.  This means
that when running tests under node we will now be a little more
sensitive to use-after-exit bugs in our runtime and test code, but I
would argue this is good thing.

This also means we no longer need to define logExceptionOnExit under
node, which is a code size saving.

Author: sbc100

emscripten.py

@@ -716,6 +716,22 @@ def create_sending(metadata, library_symbols):
 
 def make_export_wrappers(exports, delay_assignment):
   wrappers = []
+
+  # The emscripten stack functions are called very early (by writeStackCookie) before
+  # the runtime is initialized so we can't create these wrappers that check for
+  # runtimeInitialized.
+  # Likewise `__trap` can occur before the runtime is initialized since it is used in
+  # abort.
+  # pthread_self and _emscripten_proxy_execute_task_queue are currently called in some
+  # cases after the runtime has exited.
+  # TODO: Look into removing these, and improving our robustness around thread termination.
+  def install_wrapper(sym):
+    if sym.startswith('_asan_') or sym.startswith('emscripten_stack_'):
+      return False
+    if sym in ('__trap', 'pthread_self', '_emscripten_proxy_execute_task_queue'):
+      return False
+    return True
+
   for name in exports:
     # Tags cannot be wrapped in createExportWrapper
     if name == '__cpp_exception':
@@ -730,12 +746,7 @@ def make_export_wrappers(exports, delay_assignment):
       exported = ''
     wrapper += exported
 
-    # The emscripten stack functions are called very early (by writeStackCookie) before
-    # the runtime is initialized so we can't create these wrappers that check for
-    # runtimeInitialized.
-    # Likewise `__trap` can occur before the runtime is initialized since it is used in
-    # abort.
-    if settings.ASSERTIONS and not name.startswith('emscripten_stack_') and name != '__trap':
+    if settings.ASSERTIONS and install_wrapper(name):
       # With assertions enabled we create a wrapper that are calls get routed through, for
       # the lifetime of the program.
       if delay_assignment:

src/library_pthread.js

@@ -526,6 +526,9 @@ var LibraryPThread = {
   },
 
   $terminateWorker: function(worker) {
+#if PTHREADS_DEBUG
+    dbg('terminateWorker: ' + worker.workerID);
+#endif
     worker.terminate();
     // terminate() can be asynchronous, so in theory the worker can continue
     // to run for some amount of time after termination.  However from our POV
@@ -942,15 +945,7 @@ var LibraryPThread = {
 #if PROXY_TO_PTHREAD
     {{{ runtimeKeepalivePop() }}};
 #endif
-#if MINIMAL_RUNTIME
     _exit(returnCode);
-#else
-    try {
-      _exit(returnCode);
-    } catch (e) {
-      handleException(e);
-    }
-#endif
   },
 
   emscripten_proxy_to_main_thread_js__deps: ['$withStackSave', '_emscripten_run_in_main_runtime_thread_js'],

src/shell.js

@@ -172,24 +172,6 @@ var read_,
     readBinary,
     setWindowTitle;
 
-#if ENVIRONMENT_MAY_BE_SHELL || ENVIRONMENT_MAY_BE_NODE || ASSERTIONS
-// Normally we don't log exceptions but instead let them bubble out the top
-// level where the embedding environment (e.g. the browser) can handle
-// them.
-// However under v8 and node we sometimes exit the process direcly in which case
-// its up to use us to log the exception before exiting.
-// If we fix https://github.com/emscripten-core/emscripten/issues/15080
-// this may no longer be needed under node.
-function logExceptionOnExit(e) {
-  if (e instanceof ExitStatus) return;
-  let toLog = e;
-  if (e && typeof e == 'object' && e.stack) {
-    toLog = [e, e.stack];
-  }
-  err('exiting due to exception: ' + toLog);
-}
-#endif
-
 #if ENVIRONMENT_MAY_BE_NODE
 if (ENVIRONMENT_IS_NODE) {
 #if ENVIRONMENT && ASSERTIONS
@@ -244,7 +226,7 @@ if (ENVIRONMENT_IS_NODE) {
 #if RUNTIME_DEBUG
     dbg('node: uncaughtException: ' + ex)
 #endif
-    if (!(ex instanceof ExitStatus)) {
+    if (ex !== 'unwind' && !(ex instanceof ExitStatus) && !(ex.context instanceof ExitStatus)) {
       throw ex;
     }
   });
@@ -263,12 +245,8 @@ if (ENVIRONMENT_IS_NODE) {
 #endif
 
   quit_ = (status, toThrow) => {
-    if (keepRuntimeAlive()) {
-      process.exitCode = status;
-      throw toThrow;
-    }
-    logExceptionOnExit(toThrow);
-    process.exit(status);
+    process.exitCode = status;
+    throw toThrow;
   };
 
   Module['inspect'] = function () { return '[Emscripten Module object]'; };
@@ -360,7 +338,13 @@ if (ENVIRONMENT_IS_SHELL) {
         throw toThrow;
       }
 #endif
-      logExceptionOnExit(toThrow);
+      if (!(toThrow instanceof ExitStatus)) {
+        let toLog = toThrow;
+        if (toThrow && typeof toThrow == 'object' && toThrow.stack) {
+          toLog = [toThrow, toThrow.stack];
+        }
+        err('exiting due to exception: ' + toLog);
+      }
       quit(status);
     };
   }

src/threadprofiler.js

@@ -20,13 +20,15 @@ var emscriptenThreadProfiler = {
       document.body.appendChild(div);
       this.threadProfilerDiv = document.getElementById('threadprofiler');
     }
-    setInterval(function() { emscriptenThreadProfiler.updateUi() }, this.uiUpdateIntervalMsecs);
+    var i = setInterval(function() { emscriptenThreadProfiler.updateUi() }, this.uiUpdateIntervalMsecs);
+    addOnExit(() => clearInterval(i));
   },
 
   initializeNode: function initializeNode() {
     addOnInit(() => {
       emscriptenThreadProfiler.dumpState();
-      setInterval(function() { emscriptenThreadProfiler.dumpState() }, this.uiUpdateIntervalMsecs);
+      var i = setInterval(function() { emscriptenThreadProfiler.dumpState() }, this.uiUpdateIntervalMsecs);
+      addOnExit(() => clearInterval(i));
     });
   },
 

test/other/metadce/test_metadce_cxx_ctors1.jssize

@@ -1 +1 @@
-26171
+26046

test/other/metadce/test_metadce_cxx_ctors2.jssize

@@ -1 +1 @@
-26135
+26010

test/other/metadce/test_metadce_cxx_except.jssize

@@ -1 +1 @@
-30708
+30583

test/other/metadce/test_metadce_cxx_except_wasm.jssize

@@ -1 +1 @@
-25850
+25725

test/other/metadce/test_metadce_cxx_mangle.jssize

@@ -1 +1 @@
-30708
+30583

test/other/metadce/test_metadce_cxx_noexcept.jssize

@@ -1 +1 @@
-26171
+26046