Validate EXPORT_NAME

Fixes: #11281

Author: sbc100

emcc.py

@@ -2231,6 +2231,9 @@ def get_full_import_name(name):
     if settings.SINGLE_FILE:
       exit_with_error('NODE_CODE_CACHING saves a file on the side and is not compatible with SINGLE_FILE')
 
+  if not shared.JS.isidentifier(settings.EXPORT_NAME):
+    exit_with_error(f'EXPORT_NAME is not a valid JS identifier: `{settings.EXPORT_NAME}`')
+
   if options.tracing and settings.ALLOW_MEMORY_GROWTH:
     settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['emscripten_trace_report_memory_layout']
     settings.EXPORTED_FUNCTIONS += ['_emscripten_stack_get_current',

tests/test_other.py

@@ -10593,3 +10593,7 @@ def test_concepts(self):
   def test_link_only_setting_warning(self):
     err = self.run_process([EMCC, '-sALLOW_MEMORY_GROWTH', '-c', test_file('hello_world.c')], stderr=PIPE).stderr
     self.assertContained("warning: linker setting ignored during compilation: 'ALLOW_MEMORY_GROWTH' [-Wunused-command-line-argument]", err)
+
+  def test_bad_export_name(self):
+    err = self.expect_fail([EMCC, '-sEXPORT_NAME=foo bar', test_file('hello_world.c')])
+    self.assertContained('error: EXPORT_NAME is not a valid JS identifier: `foo bar`', err)

tools/shared.py

@@ -678,6 +678,11 @@ def is_legal_sig(sig):
       return True
     return sig == JS.legalize_sig(sig)
 
+  @staticmethod
+  def isidentifier(name):
+    # https://stackoverflow.com/questions/43244604/check-that-a-string-is-a-valid-javascript-identifier-name-using-python-3
+    return name.replace('$', '_').isidentifier()
+
   @staticmethod
   def make_dynCall(sig, args):
     # wasm2c and asyncify are not yet compatible with direct wasm table calls