Fix exporting of native symbol aliases (e.g. wasmTable) (#25539)

This was broken by #25376.

Author: sbc100

src/modules.mjs

@@ -433,6 +433,11 @@ function exportSymbol(name) {
 function exportRuntimeSymbols() {
   // optionally export something.
   function shouldExport(name) {
+    // Native exports are not available to be exported initially.  Instead,
+    // they get exported later in `assignWasmExports`.
+    if (nativeAliases[name]) {
+      return false;
+    }
     // If requested to be exported, export it.
     if (EXPORTED_RUNTIME_METHODS.has(name)) {
       // Unless we are in MODULARIZE=instance mode then HEAP objects are

test/test_other.py

@@ -4948,6 +4948,35 @@ def test_jslib_aliases(self, args):
 '''
     self.do_runf('main.c', expected, cflags=['--js-library', 'foo.js'] + args)
 
+  @parameterized({
+    '': ([],),
+    'closure': (['--closure=1'],),
+  })
+  def test_jslib_export_alias(self, args):
+    create_file('lib.js', '''
+      addToLibrary({
+        $foo: 'main',
+        $bar: '__indirect_function_table',
+        $baz: 'memory',
+      });
+    ''')
+    create_file('extern_pre.js', r'''
+      Module = {
+        onRuntimeInitialized: () => {
+          const assert = require('assert');
+          console.log("onRuntimeInitialized");
+          console.log('foo:', typeof Module.foo)
+          console.log('bar:', typeof Module.bar)
+          console.log('baz:', typeof Module.baz)
+          assert(Module.foo instanceof Function);
+          assert(Module.bar instanceof WebAssembly.Table);
+          assert(Module.baz instanceof WebAssembly.Memory);
+          console.log('done');
+        }
+      };
+    ''')
+    self.do_runf('hello_world.c', 'done\n', cflags=['--js-library=lib.js', '--extern-pre-js=extern_pre.js', '-sEXPORTED_RUNTIME_METHODS=foo,bar,baz'] + args)
+
   def test_postjs_errors(self):
     create_file('post.js', '#preprocess\n#error This is an error')
     err = self.expect_fail([EMCC, test_file('hello_world.c'), '--post-js', 'post.js'])

tools/emscripten.py

@@ -980,6 +980,7 @@ def create_receiving(function_exports, other_exports, library_symbols, aliases):
     assert alias in exports, f'expected alias target ({alias}) to be exported'
     alias_inverse_map.setdefault(alias, []).append(sym)
 
+  do_module_exports = (settings.MODULARIZE or not settings.MINIMAL_RUNTIME) and settings.MODULARIZE != 'instance'
   receiving.append('\nfunction assignWasmExports(wasmExports) {')
   for sym, sig in exports.items():
     is_function = sig is not None
@@ -988,11 +989,13 @@ def create_receiving(function_exports, other_exports, library_symbols, aliases):
     if generate_dyncall_assignment and is_function and sym.startswith('dynCall_'):
       sig_str = sym.replace('dynCall_', '')
       assignment += f" = dynCalls['{sig_str}']"
-    if (settings.MODULARIZE or not settings.MINIMAL_RUNTIME) and should_export(mangled) and settings.MODULARIZE != 'instance':
+    if do_module_exports and should_export(mangled):
       assignment += f" = Module['{mangled}']"
     if sym in alias_inverse_map:
       for target in alias_inverse_map[sym]:
         assignment += f" = {target}"
+        if do_module_exports and target in settings.EXPORTED_RUNTIME_METHODS:
+          assignment += f" = Module['{target}']"
     if is_function and install_debug_wrapper(sym):
       nargs = len(sig.params)
       receiving.append(f"  {assignment} = createExportWrapper('{sym}', {nargs});")