Don't allow legacy settings in strict mode (#8261)

In strict mode (`EMCC_STRICT=1` or `-s STRICT`) treat any usage
of legacy settings as an error.

We don't even attach the legacy settings in this case so it becomes
impossible to depend on legacy settings.

Also, move SAFE_HEAP and ASM_JS out of legacy settings.  These
settings are still used, they just need to have their values verified.

See #8257

Author: sbc100

emcc.py

@@ -829,8 +829,11 @@ def detect_fixed_language_mode(args):
     has_header_inputs = False
     lib_dirs = [shared.path_from_root('system', 'local', 'lib'),
                 shared.path_from_root('system', 'lib')]
-    for i in range(len(newargs)): # find input files XXX this a simple heuristic. we should really analyze based on a full understanding of gcc params,
-                                  # right now we just assume that what is left contains no more |-x OPT| things
+
+    # find input files this a simple heuristic. we should really analyze
+    # based on a full understanding of gcc params, right now we just assume that
+    # what is left contains no more |-x OPT| things
+    for i in range(len(newargs)):
       arg = newargs[i]
       if i > 0:
         prev = newargs[i - 1]
@@ -945,18 +948,16 @@ def detect_fixed_language_mode(args):
     if options.separate_asm:
       shared.Settings.SEPARATE_ASM = shared.JS.get_subresource_location(asm_target)
 
-    if 'EMCC_STRICT' in os.environ:
-      shared.Settings.STRICT = os.environ.get('EMCC_STRICT') != '0'
-
-    # Libraries are searched before settings_changes are applied, so apply the value for STRICT and ERROR_ON_MISSING_LIBRARIES from
-    # command line already now.
+    # Libraries are searched before settings_changes are applied, so apply the
+    # value for STRICT and ERROR_ON_MISSING_LIBRARIES from command line already
+    # now.
 
     def get_last_setting_change(setting):
       return ([None] + [x for x in settings_changes if x.startswith(setting + '=')])[-1]
 
     strict_cmdline = get_last_setting_change('STRICT')
     if strict_cmdline:
-      shared.Settings.STRICT = int(strict_cmdline[len('STRICT='):])
+      shared.Settings.STRICT = int(strict_cmdline.split('=', 1)[1])
 
     if shared.Settings.STRICT:
       shared.Settings.ERROR_ON_MISSING_LIBRARIES = 1

src/settings.js

@@ -1392,14 +1392,14 @@ var DISABLE_DEPRECATED_FIND_EVENT_TARGET_BEHAVIOR = 0;
 // to explicitly choose to disable HTML minification altogether.
 var MINIFY_HTML = 1;
 
-// Legacy settings that have been removed, and the values they are now fixed to. These can no
-// longer be changed:
-// [OPTION_NAME, POSSIBLE_VALUES, ERROR_EXPLANATION], where POSSIBLE_VALUES is an array of values that will
-// still be silently accepted by the compiler. First element in the list is the canonical/fixed value going forward.
-// This allows existing build systems to keep specifying one of the supported settings, for backwards compatibility.
+// Legacy settings that have been removed, and the values they are now fixed to.
+// These can no longer be changed:
+// [OPTION_NAME, POSSIBLE_VALUES, ERROR_EXPLANATION], where POSSIBLE_VALUES is
+// an array of values that will still be silently accepted by the compiler.
+// First element in the list is the canonical/fixed value going forward.
+// This allows existing build systems to keep specifying one of the supported
+// settings, for backwards compatibility.
 var LEGACY_SETTINGS = [
-  ['ASM_JS', [1, 2], 'ASM_JS must be enabled in fastcomp'],
-  ['SAFE_HEAP', [0, 1], 'safe heap must be 0 or 1 in fastcomp'],
   ['UNALIGNED_MEMORY', [0], 'forced unaligned memory not supported in fastcomp'],
   ['FORCE_ALIGNED_MEMORY', [0], 'forced aligned memory is not supported in fastcomp'],
   ['PGO', [0], 'pgo no longer supported'],

tests/test_other.py

@@ -9042,9 +9042,16 @@ def test_minimal_runtime_code_size(self):
     asmjs = ['-s', 'WASM=0', '--separate-asm', '-s', 'ELIMINATE_DUPLICATE_FUNCTIONS=1', '--memory-init-file', '1']
     opts = ['-O3', '--closure', '1', '-DNDEBUG', '-ffast-math']
 
-    hello_world_sources = [path_from_root('tests', 'small_hello_world.c'), '-s', 'RUNTIME_FUNCS_TO_IMPORT=[]', '-s', 'USES_DYNAMIC_ALLOC=0', '-s', 'ASM_PRIMITIVE_VARS=[STACKTOP]']
-    hello_webgl_sources = [path_from_root('tests', 'minimal_webgl', 'main.cpp'), path_from_root('tests', 'minimal_webgl', 'webgl.c'), '--js-library', path_from_root('tests', 'minimal_webgl', 'library_js.js'),
-                           '-s', 'RUNTIME_FUNCS_TO_IMPORT=[]', '-s', 'USES_DYNAMIC_ALLOC=2', '-lGL', '-s', 'MODULARIZE=1']
+    hello_world_sources = [path_from_root('tests', 'small_hello_world.c'),
+                           '-s', 'RUNTIME_FUNCS_TO_IMPORT=[]',
+                           '-s', 'USES_DYNAMIC_ALLOC=0',
+                           '-s', 'ASM_PRIMITIVE_VARS=[STACKTOP]']
+    hello_webgl_sources = [path_from_root('tests', 'minimal_webgl', 'main.cpp'),
+                           path_from_root('tests', 'minimal_webgl', 'webgl.c'),
+                           '--js-library', path_from_root('tests', 'minimal_webgl', 'library_js.js'),
+                           '-s', 'RUNTIME_FUNCS_TO_IMPORT=[]',
+                           '-s', 'USES_DYNAMIC_ALLOC=2', '-lGL',
+                           '-s', 'MODULARIZE=1']
     hello_webgl2_sources = hello_webgl_sources + ['-s', 'USE_WEBGL2=1']
 
     test_cases = [
@@ -9102,3 +9109,16 @@ def test_legacy_settings_forbidden_to_change(self):
 
     run_process([PYTHON, EMCC, '-s', 'MEMFS_APPEND_TO_TYPED_ARRAYS=1', path_from_root('tests', 'hello_world.c')])
     run_process([PYTHON, EMCC, '-s', 'PRECISE_I64_MATH=2', path_from_root('tests', 'hello_world.c')])
+
+  def test_legacy_settings_strict_mode(self):
+    cmd = [PYTHON, EMCC, path_from_root('tests', 'hello_world.c'), '-s', 'SPLIT_MEMORY=0']
+    run_process(cmd)
+
+    with env_modify({'EMCC_STRICT': '1'}):
+      proc = run_process(cmd, stderr=PIPE, check=False)
+      self.assertNotEqual(proc.returncode, 0)
+      self.assertContained('legacy setting used in strict mode: SPLIT_MEMORY', proc.stderr)
+
+    proc = run_process(cmd + ['-s', 'STRICT=1'], stderr=PIPE, check=False)
+    self.assertNotEqual(proc.returncode, 0)
+    self.assertContained('legacy setting used in strict mode: SPLIT_MEMORY', proc.stderr)

tests/test_sanity.py

@@ -331,7 +331,7 @@ def test_llvm_fastcomp(self):
 
     restore_and_set_up()
 
-    self.check_working([EMCC] + MINIMAL_HELLO_WORLD + ['-s', 'ASM_JS=0'], '''ASM_JS must be enabled in fastcomp''')
+    self.check_working([EMCC] + MINIMAL_HELLO_WORLD + ['-s', 'ASM_JS=0'], 'ASM_JS can only be set to either 1 or 2')
 
   def test_node(self):
     NODE_WARNING = 'node version appears too old'

tools/shared.py

@@ -1138,8 +1138,15 @@ def reset(self):
       settings = re.sub(r'var ([\w\d]+)', r'attrs["\1"]', settings)
       exec(settings, {'attrs': self.attrs})
 
-      for opt, fixed_values, _ in self.attrs['LEGACY_SETTINGS']:
-        self.attrs[opt] = fixed_values[0]
+      if 'EMCC_STRICT' in os.environ:
+        self.attrs['STRICT'] = int(os.environ.get('EMCC_STRICT'))
+
+      self.legacy_settings = {}
+      for name, fixed_values, err in self.attrs['LEGACY_SETTINGS']:
+        self.legacy_settings[name] = (fixed_values, err)
+        assert name not in self.attrs, 'legacy setting (%s) cannot also be a regular setting' % name
+        if not self.attrs['STRICT']:
+          self.attrs[name] = fixed_values[0]
 
       if get_llvm_target() == WASM_TARGET:
         self.attrs['WASM_BACKEND'] = 1
@@ -1172,19 +1179,24 @@ def apply_opt_level(self, opt_level, shrink_level=0, noisy=False):
       if shrink_level >= 2:
         self.attrs['EVAL_CTORS'] = 1
 
+    def keys(self):
+      return self.attrs.keys()
+
     def __getattr__(self, attr):
       if attr in self.attrs:
         return self.attrs[attr]
       else:
-        raise AttributeError
+        raise AttributeError("Settings object has no attribute '%s'" % attr)
 
     def __setattr__(self, attr, value):
-      for legacy_attr, fixed_values, error_message in self.attrs['LEGACY_SETTINGS']:
-        if attr == legacy_attr:
-          if value not in fixed_values:
-            exit_with_error('Invalid command line option -s ' + attr + '=' + str(value) + ': ' + error_message)
-          else:
-            logger.debug('Option -s ' + attr + '=' + str(value) + ' has been removed from the codebase. (' + error_message + ')')
+      if attr in self.legacy_settings:
+        if self.attrs['STRICT']:
+          exit_with_error('legacy setting used in strict mode: %s', attr)
+        fixed_values, error_message = self.legacy_settings[attr]
+        if value not in fixed_values:
+          exit_with_error('Invalid command line option -s ' + attr + '=' + str(value) + ': ' + error_message)
+        else:
+          logger.debug('Option -s ' + attr + '=' + str(value) + ' has been removed from the codebase. (' + error_message + ')')
 
       if attr not in self.attrs:
         logger.error('Assigning a non-existent settings attribute "%s"' % attr)
@@ -1230,6 +1242,12 @@ def __getitem__(self, key):
 
 
 def verify_settings():
+  if Settings.ASM_JS not in [1, 2]:
+    exit_with_error('ASM_JS can only be set to either 1 or 2')
+
+  if Settings.SAFE_HEAP not in [0, 1]:
+    exit_with_error('SAVE_HEAP must be 0 or 1 in fastcomp')
+
   if Settings.WASM and Settings.EXPORT_FUNCTION_TABLES:
       exit_with_error('emcc: EXPORT_FUNCTION_TABLES incompatible with WASM')