Remove support for 3 deprecated settings (#23975)

This change marks these settings and legacy and removes the associated
code:

- SUPPORT_ERRNO
- EXTRA_EXPORTED_RUNTIME_METHODS
- DEMANGLE_SUPPORT

These settings have been marked as deprecated for over a year now since
the system for settings deprecation was added in #21355.

Author: sbc100

ChangeLog.md

@@ -26,6 +26,12 @@ See docs/process.md for more on how version tagging works.
   using `-gsource-map=inline`. (#23741)
 - The python `__file__` builtin now works in the emscripten config file.
   (#23973)
+- Three deprecated settings were removed.  These settings were marked as
+  deprecated for more than year:
+  - SUPPORT_ERRNO: Instead, export `__errno_location` if needed.
+  - EXTRA_EXPORTED_RUNTIME_METHODS: Instead use EXPORTED_RUNTIME_METHODS.
+  - DEMANGLE_SUPPORT: Instead use the `$demangle` JS libary function.
+  (#23975)
 
 4.0.5 - 03/12/25
 ----------------

site/source/docs/tools_reference/settings_reference.rst

@@ -482,17 +482,6 @@ Print out exceptions in emscriptened code.
 
 Default value: false
 
-.. _demangle_support:
-
-DEMANGLE_SUPPORT
-================
-
-If 1, export `demangle` and `stackTrace` JS library functions.
-
-.. note:: This setting is deprecated
-
-Default value: false
-
 .. _library_debug:
 
 LIBRARY_DEBUG
@@ -1442,17 +1431,6 @@ having "FS" in this list.
 
 Default value: []
 
-.. _extra_exported_runtime_methods:
-
-EXTRA_EXPORTED_RUNTIME_METHODS
-==============================
-
-Deprecated, use EXPORTED_RUNTIME_METHODS instead.
-
-.. note:: This setting is deprecated
-
-Default value: []
-
 .. _incoming_module_js_api:
 
 INCOMING_MODULE_JS_API
@@ -2951,18 +2929,6 @@ feature_matrix.py).
 
 Default value: 160000
 
-.. _support_errno:
-
-SUPPORT_ERRNO
-=============
-
-Whether we support setting errno from JS library code.
-In MINIMAL_RUNTIME builds, this option defaults to 0.
-
-.. note:: This setting is deprecated
-
-Default value: true
-
 .. _minimal_runtime:
 
 MINIMAL_RUNTIME

src/lib/liblegacy.js

@@ -76,21 +76,6 @@ legacyFuncs = {
   $allocateUTF8: '$stringToNewUTF8',
   $allocateUTF8OnStack: '$stringToUTF8OnStack',
 
-#if SUPPORT_ERRNO
-  $setErrNo__deps: ['__errno_location'],
-  $setErrNo: (value) => {
-    {{{makeSetValue("___errno_location()", 0, 'value', 'i32') }}};
-    return value;
-  },
-#else
-  $setErrNo: (value) => {
-#if ASSERTIONS
-    err('failed to set errno from JS');
-#endif
-    return 0;
-  },
-#endif
-
 #if LINK_AS_CXX
   $demangle__deps: ['$withStackSave', '__cxa_demangle', 'free', '$stringToUTF8OnStack'],
   $demangle: (func) => {

src/settings.js

@@ -351,11 +351,6 @@ var EMULATE_FUNCTION_POINTER_CASTS = false;
 // [link]
 var EXCEPTION_DEBUG = false;
 
-// If 1, export `demangle` and `stackTrace` JS library functions.
-// [link]
-// [deprecated]
-var DEMANGLE_SUPPORT = false;
-
 // Print out when we enter a library call (library*.js). You can also unset
 // runtimeDebug at runtime for logging to cease, and can set it when you want
 // it back. A simple way to set it in C++ is::
@@ -970,10 +965,6 @@ var JSPI_IMPORTS = [];
 // [link]
 var EXPORTED_RUNTIME_METHODS = [];
 
-// Deprecated, use EXPORTED_RUNTIME_METHODS instead.
-// [deprecated]
-var EXTRA_EXPORTED_RUNTIME_METHODS = [];
-
 // A list of incoming values on the Module object in JS that we care about. If
 // a value is not in this list, then we don't emit code to check if you provide
 // it on the Module object. For example, if
@@ -1928,12 +1919,6 @@ var MIN_CHROME_VERSION = 85;
 // feature_matrix.py).
 var MIN_NODE_VERSION = 160000;
 
-// Whether we support setting errno from JS library code.
-// In MINIMAL_RUNTIME builds, this option defaults to 0.
-// [link]
-// [deprecated]
-var SUPPORT_ERRNO = true;
-
 // If true, uses minimal sized runtime without POSIX features, Module,
 // preRun/preInit/etc., Emscripten built-in XHR loading or library_browser.js.
 // Enable this setting to target the smallest code size possible.  Set
@@ -2285,4 +2270,7 @@ var LEGACY_SETTINGS = [
   ['WORKAROUND_OLD_WEBGL_UNIFORM_UPLOAD_IGNORED_OFFSET_BUG', [0], 'No longer supported'],
   ['AUTO_ARCHIVE_INDEXES', [0, 1], 'No longer needed'],
   ['USE_ES6_IMPORT_META', [1], 'Disabling is no longer supported'],
+  ['EXTRA_EXPORTED_RUNTIME_METHODS', [[]], 'No longer supported, use EXPORTED_RUNTIME_METHODS'],
+  ['SUPPORT_ERRNO', [0], 'No longer supported'],
+  ['DEMANGLE_SUPPORT', [0], 'No longer supported'],
 ];

test/other/codesize/test_codesize_cxx_mangle.gzsize

@@ -1 +1 @@
-9244
+9277

test/other/codesize/test_codesize_cxx_mangle.jssize

@@ -1 +1 @@
-23720
+23834

test/other/codesize/test_codesize_hello_O0.gzsize

@@ -1 +1 @@
-7984
+7977

test/other/codesize/test_codesize_hello_O0.jssize

@@ -1 +1 @@
-21327
+21318

test/other/test_support_errno.c

@@ -1 +1 @@
-52673
+52659

test/other/test_support_errno.out

@@ -3958,6 +3958,8 @@ def test_demangle(self):
       #include <stdio.h>
       #include <emscripten.h>
 
+      EM_JS_DEPS(deps, "$demangle,$stackTrace");
+
       void two(char c) {
         EM_ASM(out(stackTrace()));
       }
@@ -3989,7 +3991,7 @@ def test_demangle(self):
 
     # full demangle support
 
-    self.run_process([EMXX, 'src.cpp', '-sDEMANGLE_SUPPORT'])
+    self.run_process([EMXX, 'src.cpp', '-sEXPORTED_FUNCTIONS=_main,_free,___cxa_demangle'])
     output = self.run_js('a.out.js')
     self.assertContained('''operator new(unsigned long)
 _main
@@ -4010,7 +4012,7 @@ def test_demangle(self):
 void wakaw::Cm::RasterBase<wakaw::watwat::Polocator>::merbine1<wakaw::Cm::RasterBase<wakaw::watwat::Polocator>::OR>(unsigned int const*, unsigned int)
 ''', output)
     # test for multiple functions in one stack trace
-    self.run_process([EMXX, 'src.cpp', '-sDEMANGLE_SUPPORT', '-g'])
+    self.run_process([EMXX, 'src.cpp', '-sEXPORTED_FUNCTIONS=_main,_free,___cxa_demangle', '-g'])
     output = self.run_js('a.out.js')
     self.assertIn('one(int)', output)
     self.assertIn('two(char)', output)
@@ -9184,7 +9186,7 @@ def test_codesize_minimal_pthreads(self):
     'except':   (['-O2', '-fexceptions'],    [], ['waka']), # noqa
     # exceptions does not pull in demangling by default, which increases code size
     'mangle':   (['-O2', '-fexceptions',
-                  '-sDEMANGLE_SUPPORT', '-Wno-deprecated'], [], ['waka']), # noqa
+                  '-sEXPORTED_FUNCTIONS=_main,_free,___cxa_demangle', '-Wno-deprecated'], [], ['waka']), # noqa
     # Wasm EH's code size increase is smaller than that of Emscripten EH
     'except_wasm':   (['-O2', '-fwasm-exceptions', '-sWASM_LEGACY_EXCEPTIONS=0'], [], ['waka']),
     'except_wasm_legacy':   (['-O2', '-fwasm-exceptions', '-sWASM_LEGACY_EXCEPTIONS'], [], ['waka']),
@@ -9262,19 +9264,9 @@ def test_codesize_libcxxabi_message(self, *args):
   def test_codesize_files(self, *args):
     self.run_codesize_test('files.cpp', *args)
 
-  # ensures runtime exports work, even with metadce
-  @parameterized({
-    '': (False,),
-    'legacy': (True,)
-  })
-  def test_exported_runtime_methods_metadce(self, use_legacy_name):
+  def test_exported_runtime_methods_metadce(self):
     exports = ['stackSave', 'stackRestore', 'stackAlloc', 'FS']
-    setting_name = 'EXPORTED_RUNTIME_METHODS'
-    if use_legacy_name:
-      setting_name = 'EXTRA_EXPORTED_RUNTIME_METHODS'
-    err = self.run_process([EMCC, test_file('hello_world.c'), '-Os', '-s%s=%s' % (setting_name, ','.join(exports))], stderr=PIPE).stderr
-    if use_legacy_name:
-      self.assertContained('warning: EXTRA_EXPORTED_RUNTIME_METHODS is deprecated (please use EXPORTED_RUNTIME_METHODS instead). Please open a bug if you have a continuing need for this setting [-Wdeprecated]', err)
+    self.run_process([EMCC, test_file('hello_world.c'), '-Os', '-sEXPORTED_RUNTIME_METHODS=%s' % ','.join(exports)])
     js = read_file('a.out.js')
     for export in exports:
       self.assertContained(f'Module["{export}"]', js)
@@ -12956,24 +12948,6 @@ def test_default_to_cxx(self):
     self.run_process([EMCC, '-x', 'c++-header', '-c', 'cxxfoo.h'])
     self.run_process([EMCC, '-x', 'c++', '-c', 'cxxfoo.h'])
 
-  @parameterized({
-    '': ([],),
-    'minimal': (['-sMINIMAL_RUNTIME', '-sSUPPORT_ERRNO'],),
-  })
-  def test_support_errno(self, args):
-    self.emcc_args += args + ['-sEXPORTED_FUNCTIONS=_main,___errno_location', '-Wno-deprecated']
-
-    self.do_other_test('test_support_errno.c')
-    size_default = os.path.getsize('test_support_errno.js')
-
-    # Run the same test again but with SUPPORT_ERRNO disabled.  This time we don't expect errno
-    # to be set after the failing syscall.
-    self.emcc_args += ['-sSUPPORT_ERRNO=0']
-    self.do_other_test('test_support_errno.c', out_suffix='_disabled')
-
-    # Verify the JS output was smaller
-    self.assertLess(os.path.getsize('test_support_errno.js'), size_default)
-
   def test_assembly(self):
     self.run_process([EMCC, '-c', test_file('other/test_asm.s'), '-o', 'foo.o'])
     self.do_other_test('test_asm.c', libraries=['foo.o'])

test/other/test_support_errno_disabled.out

@@ -734,9 +734,6 @@ def phase_linker_setup(options, linker_args):  # noqa: C901, PLR0912, PLR0915
     if s in user_settings:
       diagnostics.warning('deprecated', f'{s} is deprecated ({reason}). Please open a bug if you have a continuing need for this setting')
 
-  if settings.EXTRA_EXPORTED_RUNTIME_METHODS:
-    settings.EXPORTED_RUNTIME_METHODS += settings.EXTRA_EXPORTED_RUNTIME_METHODS
-
   # If no output format was specified we try to deduce the format based on
   # the output filename extension
   if not options.oformat and (options.relocatable or (options.shared and not settings.SIDE_MODULE)):
@@ -1303,10 +1300,6 @@ def phase_linker_setup(options, linker_args):  # noqa: C901, PLR0912, PLR0915
         '_wasmfs_get_cwd',
       ]
 
-  if settings.DEMANGLE_SUPPORT:
-    settings.REQUIRED_EXPORTS += ['__cxa_demangle', 'free']
-    settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$demangle', '$stackTrace']
-
   if settings.FULL_ES3:
     settings.FULL_ES2 = 1
     settings.MAX_WEBGL_VERSION = max(2, settings.MAX_WEBGL_VERSION)
@@ -1799,7 +1792,6 @@ def get_full_import_name(name):
   # Some settings make no sense when not linking as C++
   if not settings.LINK_AS_CXX:
     cxx_only_settings = [
-      'DEMANGLE_SUPPORT',
       'EXCEPTION_DEBUG',
       'DISABLE_EXCEPTION_CATCHING',
       'EXCEPTION_CATCHING_ALLOWED',

test/other/test_unoptimized_code_size.js.size

@@ -120,9 +120,6 @@
 #
 # All settings here should be tagged as `[deprecated]` in settings.js
 DEPRECATED_SETTINGS = {
-    'SUPPORT_ERRNO': 'emscripten no longer uses the setErrNo library function',
-    'EXTRA_EXPORTED_RUNTIME_METHODS': 'please use EXPORTED_RUNTIME_METHODS instead',
-    'DEMANGLE_SUPPORT': 'mangled names no longer appear in stack traces',
     'RUNTIME_LINKED_LIBS': 'you can simply list the libraries directly on the commandline now',
     'CLOSURE_WARNINGS': 'use -Wclosure instead',
     'LEGALIZE_JS_FFI': 'to disable JS type legalization use `-sWASM_BIGINT` or `-sSTANDALONE_WASM`',