Allow arbitrary export names when not generating JS output (#24427)

Fixes: #24413

Author: sbc100

test/test_other.py

@@ -5801,13 +5801,13 @@ def test_bad_function_pointer_cast(self, opts, wasm, safe):
           self.assertContained('function signature mismatch', output)
 
   def test_bad_export(self):
-    for m in ('', ' '):
+    for exports in ('_main', '_main,foo'):
       self.clear()
-      cmd = [EMCC, test_file('hello_world.c'), '-sEXPORTED_FUNCTIONS=["' + m + '_main"]']
+      cmd = [EMCC, test_file('hello_world.c'), f'-sEXPORTED_FUNCTIONS={exports}']
       print(cmd)
       stderr = self.run_process(cmd, stderr=PIPE, check=False).stderr
-      if m:
-        self.assertContained('undefined exported symbol: " _main"', stderr)
+      if 'foo' in exports:
+        self.assertContained('undefined exported symbol: "foo"', stderr)
       else:
         self.assertContained('hello, world!', self.run_js('a.out.js'))
 
@@ -11350,13 +11350,13 @@ def test_dash_s_list_parsing(self):
       # Simple one-per-line response file format
       ("[email protected]", ''),
       # stray slash
-      ("EXPORTED_FUNCTIONS=['_a', '_b', \\'_c', '_d']", '''undefined exported symbol: "\\\\'_c'"'''),
+      ("EXPORTED_FUNCTIONS=['_a', '_b', \\'_c', '_d']", '''invalid export name: "\\\\'_c'"'''),
       # stray slash
-      ("EXPORTED_FUNCTIONS=['_a', '_b',\\ '_c', '_d']", '''undefined exported symbol: "\\\\ '_c'"'''),
+      ("EXPORTED_FUNCTIONS=['_a', '_b',\\ '_c', '_d']", '''invalid export name: "\\\\ '_c'"'''),
       # stray slash
-      ('EXPORTED_FUNCTIONS=["_a", "_b", \\"_c", "_d"]', 'undefined exported symbol: "\\\\"_c""'),
+      ('EXPORTED_FUNCTIONS=["_a", "_b", \\"_c", "_d"]', 'invalid export name: "\\\\"_c""'),
       # stray slash
-      ('EXPORTED_FUNCTIONS=["_a", "_b",\\ "_c", "_d"]', 'undefined exported symbol: "\\\\ "_c"'),
+      ('EXPORTED_FUNCTIONS=["_a", "_b",\\ "_c", "_d"]', 'invalid export name: "\\\\ "_c"'),
       # missing comma
       ('EXPORTED_FUNCTIONS=["_a", "_b" "_c", "_d"]', 'wasm-ld: error: symbol exported via --export not found: b" "_c'),
     ]:
@@ -16114,7 +16114,11 @@ def test_cxx20_modules_std_headers(self):
   def test_invalid_export_name(self):
     create_file('test.c', '__attribute__((export_name("my.func"))) void myfunc() {}')
     err = self.expect_fail([EMCC, 'test.c'])
-    self.assertContained('emcc: error: invalid export name: "my.func"', err)
+    self.assertContained('emcc: error: invalid export name: "_my.func"', err)
+
+    # When we are generating only wasm and not JS we don't need exports to
+    # be valid JS symbols.
+    self.run_process([EMCC, 'test.c', '--no-entry', '-o', 'out.wasm'])
 
     # GCC (and clang) and JavaScript also allow $ in symbol names
     create_file('valid.c', '''

tools/emscripten.py

@@ -364,6 +364,10 @@ def emscript(in_wasm, out_wasm, outfile_js, js_syms, finalize=True, base_metadat
     logger.debug('emscript: skipping js glue generation')
     return
 
+  for e in settings.EXPORTED_FUNCTIONS:
+    if not js_manipulation.isidentifier(e):
+      exit_with_error(f'invalid export name: "{e}"')
+
   # memory and global initializers
 
   if settings.RELOCATABLE:
@@ -562,9 +566,6 @@ def finalize_wasm(infile, outfile, js_syms):
   # These are any exports that were not requested on the command line and are
   # not known auto-generated system functions.
   unexpected_exports = [e for e in metadata.all_exports if shared.is_user_export(e)]
-  for n in unexpected_exports:
-    if not js_manipulation.isidentifier(n):
-      exit_with_error(f'invalid export name: "{n}"')
   unexpected_exports = [asmjs_mangle(e) for e in unexpected_exports]
   unexpected_exports = [e for e in unexpected_exports if e not in expected_exports]