Refactor legacy cmdline flag handling

This does turn some warnings into errors, but I also think its
appropriate to error when unsupported command line flags are passed.

Author: sbc100

test/test_other.py

@@ -3691,9 +3691,7 @@ def test_embind_tsgen_exceptions(self, legacy):
     # Check that when Wasm exceptions and assertions are enabled bindings still generate.
     self.run_process([EMXX, test_file('other/embind_tsgen.cpp'),
                       '-lembind', '-fwasm-exceptions', '-sASSERTIONS',
-                      # Use the deprecated `--embind-emit-tsd` to ensure it
-                      # still works until removed.
-                      '--embind-emit-tsd', 'embind_tsgen.d.ts', '-Wno-deprecated'] +
+                      '--emit-tsd', 'embind_tsgen.d.ts', '-Wno-deprecated'] +
                      self.get_cflags())
     self.assertFileContents(test_file('other/embind_tsgen.d.ts'), read_file('embind_tsgen.d.ts'))
 
@@ -11495,11 +11493,12 @@ def test_backwards_deps_in_archive(self):
 
   def test_warning_flags(self):
     self.run_process([EMCC, '-c', '-o', 'hello.o', test_file('hello_world.c')])
-    cmd = [EMCC, 'hello.o', '-o', 'a.js', '-g', '--llvm-opts=""']
+    # -g4 will generte a deprecated warning
+    cmd = [EMCC, 'hello.o', '-o', 'a.js', '-g4']
 
     # warning that is enabled by default
     stderr = self.run_process(cmd, stderr=PIPE).stderr
-    self.assertContained('emcc: warning: --llvm-opts is deprecated.  All non-emcc args are passed through to clang. [-Wdeprecated]', stderr)
+    self.assertContained('emcc: warning: please replace -g4 with -gsource-map [-Wdeprecated]', stderr)
 
     # -w to suppress warnings
     stderr = self.run_process(cmd + ['-w'], stderr=PIPE).stderr
@@ -11510,12 +11509,12 @@ def test_warning_flags(self):
     self.assertNotContained('warning', stderr)
 
     # with -Werror should fail
-    expected = 'error: --llvm-opts is deprecated.  All non-emcc args are passed through to clang. [-Wdeprecated] [-Werror]'
+    expected = 'error: please replace -g4 with -gsource-map [-Wdeprecated] [-Werror]'
     self.assert_fail(cmd + ['-Werror'], expected)
 
     # with -Werror + -Wno-error=<type> should only warn
     stderr = self.run_process(cmd + ['-Werror', '-Wno-error=deprecated'], stderr=PIPE).stderr
-    self.assertContained('emcc: warning: --llvm-opts is deprecated.  All non-emcc args are passed through to clang. [-Wdeprecated]', stderr)
+    self.assertContained('emcc: warning: please replace -g4 with -gsource-map [-Wdeprecated]', stderr)
 
     # check that `-Werror=foo` also enales foo
     expected = 'error: use of legacy setting: TOTAL_MEMORY (setting renamed to INITIAL_MEMORY) [-Wlegacy-settings] [-Werror]'

tools/cmdline.py

@@ -210,6 +210,9 @@ def parse_args(newargs):  # noqa: C901, PLR0912, PLR0915
   """
   should_exit = False
   skip = False
+  LEGACY_ARGS = {'--js-opts', '--llvm-opts', '--llvm-lto', '--memory-init-file'}
+  LEGACY_FLAGS = {'--separate-asm', '--jcache', '--proxy-to-worker', '--default-obj-ext',
+                  '--embind-emit-tsd', '--remove-duplicates', '--no-heap-copy'}
 
   for i in range(len(newargs)):
     if skip:
@@ -224,6 +227,9 @@ def parse_args(newargs):  # noqa: C901, PLR0912, PLR0915
     arg = newargs[i]
     arg_value = None
 
+    if arg in LEGACY_FLAGS or any(arg.startswith(a) for a in LEGACY_ARGS):
+      exit_with_error(f'{arg} is no longer supported')
+
     if arg in CLANG_FLAGS_WITH_ARGS:
       # Ignore the next argument rather than trying to parse it.  This is needed
       # because that next arg could, for example, start with `-o` and we don't want
@@ -301,11 +307,6 @@ def consume_arg_file():
         newargs[i] = '-O3'
         level = 3
       settings.OPT_LEVEL = level
-    elif check_arg('--js-opts'):
-      logger.warning('--js-opts ignored when using llvm backend')
-      consume_arg()
-    elif check_arg('--llvm-opts'):
-      diagnostics.warning('deprecated', '--llvm-opts is deprecated.  All non-emcc args are passed through to clang.')
     elif arg.startswith('-flto'):
       if '=' in arg:
         settings.LTO = arg.split('=')[1]
@@ -315,9 +316,6 @@ def consume_arg_file():
       settings.LTO = 0
     elif arg == "--save-temps":
       options.save_temps = True
-    elif check_arg('--llvm-lto'):
-      logger.warning('--llvm-lto ignored when using llvm backend')
-      consume_arg()
     elif check_arg('--closure-args'):
       args = consume_arg()
       settings.CLOSURE_ARGS += shlex.split(args)
@@ -432,8 +430,6 @@ def consume_arg_file():
       options.exclude_files.append(consume_arg())
     elif check_flag('--use-preload-cache'):
       options.use_preload_cache = True
-    elif check_flag('--no-heap-copy'):
-      diagnostics.warning('legacy-settings', 'ignoring legacy flag --no-heap-copy (that is the only mode supported now)')
     elif check_flag('--use-preload-plugins'):
       options.use_preload_plugins = True
     elif check_flag('--ignore-dynamic-linking'):
@@ -446,17 +442,10 @@ def consume_arg_file():
       options.shell_path = consume_arg_file()
     elif check_arg('--source-map-base'):
       options.source_map_base = consume_arg()
-    elif check_arg('--embind-emit-tsd'):
-      diagnostics.warning('deprecated', '--embind-emit-tsd is deprecated.  Use --emit-tsd instead.')
-      options.emit_tsd = consume_arg()
     elif check_arg('--emit-tsd'):
       options.emit_tsd = consume_arg()
     elif check_flag('--no-entry'):
       options.no_entry = True
-    elif check_flag('--remove-duplicates'):
-      diagnostics.warning('legacy-settings', '--remove-duplicates is deprecated as it is no longer needed. If you cannot link without it, file a bug with a testcase')
-    elif check_flag('--jcache'):
-      logger.error('jcache is no longer supported')
     elif check_arg('--cache'):
       config.CACHE = os.path.abspath(consume_arg())
       cache.setup()
@@ -481,14 +470,8 @@ def consume_arg_file():
     elif check_flag('--show-ports'):
       ports.show_ports()
       should_exit = True
-    elif check_arg('--memory-init-file'):
-      exit_with_error('--memory-init-file is no longer supported')
-    elif check_flag('--proxy-to-worker'):
-      exit_with_error('--proxy-to-worker is no longer supported')
     elif check_arg('--valid-abspath'):
       options.valid_abspaths.append(consume_arg())
-    elif check_flag('--separate-asm'):
-      exit_with_error('cannot --separate-asm with the wasm backend, since not emitting asm.js')
     elif arg.startswith(('-I', '-L')):
       path_name = arg[2:]
       # Look for '/' explicitly so that we can also diagnose identically if -I/foo/bar is passed on Windows.
@@ -549,8 +532,6 @@ def consume_arg_file():
       settings.DISABLE_EXCEPTION_CATCHING = 1
     elif arg == '-ffast-math':
       options.fast_math = True
-    elif check_arg('--default-obj-ext'):
-      exit_with_error('--default-obj-ext is no longer supported by emcc')
     elif arg.startswith('-fsanitize=cfi'):
       exit_with_error('emscripten does not currently support -fsanitize=cfi')
     elif check_arg('--output_eol') or check_arg('--output-eol'):