fix case of exceptions whitelist being empty

Author: kripken

emcc

@@ -1289,8 +1289,8 @@ try:
     fastcomp_opts += ['-pnacl-abi-simplify-preopt', '-pnacl-abi-simplify-postopt']
     if shared.Settings.DISABLE_EXCEPTION_CATCHING != 1:
       fastcomp_opts += ['-enable-emscripten-cxx-exceptions']
-      if len(shared.Settings.EXCEPTION_CATCHING_WHITELIST) > 0:
-        fastcomp_opts += ['-emscripten-cxx-exceptions-whitelist=' + ','.join(shared.Settings.EXCEPTION_CATCHING_WHITELIST)]
+      if shared.Settings.DISABLE_EXCEPTION_CATCHING == 2:
+        fastcomp_opts += ['-emscripten-cxx-exceptions-whitelist=' + ','.join(shared.Settings.EXCEPTION_CATCHING_WHITELIST or ['fake'])]
 
   if shared.Settings.ASM_JS:
     assert opt_level >= 1 or fastcomp, 'asm.js requires -O1 or above'

tests/core/test_exceptions_white_list_empty.out

@@ -1347,6 +1347,33 @@ def test_exceptions_white_list(self):
     test_path = path_from_root('tests', 'core', 'test_exceptions_white_list')
     src, output = (test_path + s for s in ('.in', '.out'))
     self.do_run_from_file(src, output)
+    size = len(open('src.cpp.o.js').read())
+    shutil.copyfile('src.cpp.o.js', 'orig.js')
+
+    if os.environ.get('EMCC_FAST_COMPILER') != '0':
+      # check that an empty whitelist works properly (as in, same as exceptions disabled)
+      empty_output = path_from_root('tests', 'core', 'test_exceptions_white_list_empty.out')
+
+      Settings.EXCEPTION_CATCHING_WHITELIST = []
+      self.do_run_from_file(src, empty_output)
+      empty_size = len(open('src.cpp.o.js').read())
+      shutil.copyfile('src.cpp.o.js', 'empty.js')
+
+      Settings.EXCEPTION_CATCHING_WHITELIST = ['fake']
+      self.do_run_from_file(src, empty_output)
+      fake_size = len(open('src.cpp.o.js').read())
+      shutil.copyfile('src.cpp.o.js', 'fake.js')
+
+      Settings.DISABLE_EXCEPTION_CATCHING = 1
+      self.do_run_from_file(src, empty_output)
+      disabled_size = len(open('src.cpp.o.js').read())
+      shutil.copyfile('src.cpp.o.js', 'disabled.js')
+
+      assert size - empty_size > 2000, [empty_size, size] # big change when we disable entirely
+      assert size - fake_size > 2000, [fake_size, size]
+      assert empty_size == fake_size, [empty_size, fake_size]
+      assert empty_size - disabled_size < 100, [empty_size, disabled_size] # full disable removes a tiny bit more
+      assert fake_size - disabled_size < 100, [disabled_size, fake_size]
 
   def test_exceptions_white_list_2(self):
     Settings.DISABLE_EXCEPTION_CATCHING = 2