Warning if MAXIUMUM_MEMORY used without ALLOW_MEMORT_GROWTH. NFC (#14816)

Previously we were silently ignoring it.  We considered the alternative
which would be to automatically enable ALLOW_MEMORT_GROWTH but decided
that would be more of a breaking/surprise change.

emcc.py

@@ -1978,6 +1978,9 @@ def phase_linker_setup(options, state, newargs, settings_map):
   if settings.MEMORY_GROWTH_LINEAR_STEP != -1:
     check_memory_setting('MEMORY_GROWTH_LINEAR_STEP')
 
+  if 'MAXIMUM_MEMORY' in settings_map and not settings.ALLOW_MEMORY_GROWTH:
+    diagnostics.warning('unused-command-line-argument', 'MAXIMUM_MEMORY is only meaningful with ALLOW_MEMORY_GROWTH')
+
   if settings.EXPORT_ES6 and not settings.MODULARIZE:
     # EXPORT_ES6 requires output to be a module
     if 'MODULARIZE' in settings_map:

tests/test_core.py

@@ -2012,15 +2012,14 @@ int main(int argc, char **argv) {
     self.do_core_test('test_memorygrowth_3.c')
 
   @parameterized({
-    'nogrow': (['-s', 'ALLOW_MEMORY_GROWTH=0'],),
+    'nogrow': ([],),
-    'grow': (['-s', 'ALLOW_MEMORY_GROWTH'],)
+    'grow': (['-sALLOW_MEMORY_GROWTH', '-sMAXIMUM_MEMORY=18MB'],)
   })
   @no_asan('requires more memory when growing')
   def test_aborting_new(self, args):
     # test that C++ new properly errors if we fail to malloc when growth is
     # enabled, with or without growth
     self.emcc_args += args
-    self.set_setting('MAXIMUM_MEMORY', '18MB')
     self.do_core_test('test_aborting_new.cpp')
 
   @no_wasm2js('no WebAssembly.Memory()')

tests/test_other.py

@@ -6895,7 +6895,6 @@ int main() {
     for args, expect_initial, expect_max in [
         ([], 320, 320),
         (['-s', 'ALLOW_MEMORY_GROWTH'], 320, 32768),
-        (['-s', 'MAXIMUM_MEMORY=40MB'], 320, 320),
         (['-s', 'ALLOW_MEMORY_GROWTH', '-s', 'MAXIMUM_MEMORY=40MB'], 320, 640),
       ]:
       cmd = [EMCC, test_file('hello_world.c'), '-O2', '-s', 'INITIAL_MEMORY=20MB'] + args
@@ -6924,11 +6923,15 @@ int main() {
     ret = self.expect_fail([EMCC, test_file('hello_world.c'), '-s', 'INITIAL_MEMORY=33554433']) # 32MB + 1 byte
     self.assertContained('INITIAL_MEMORY must be a multiple of WebAssembly page size (64KiB)', ret)
 
-    self.run_process([EMCC, test_file('hello_world.c'), '-s', 'MAXIMUM_MEMORY=33MB'])
+    self.run_process([EMCC, test_file('hello_world.c'), '-s', 'MAXIMUM_MEMORY=33MB', '-s', 'ALLOW_MEMORY_GROWTH'])
 
-    ret = self.expect_fail([EMCC, test_file('hello_world.c'), '-s', 'MAXIMUM_MEMORY=34603009']) # 33MB + 1 byte
+    ret = self.expect_fail([EMCC, test_file('hello_world.c'), '-s', 'MAXIMUM_MEMORY=34603009', '-s', 'ALLOW_MEMORY_GROWTH']) # 33MB + 1 byte
     self.assertContained('MAXIMUM_MEMORY must be a multiple of WebAssembly page size (64KiB)', ret)
 
+  def test_invalid_memory_max(self):
+    err = self.expect_fail([EMCC, '-Werror', test_file('hello_world.c'), '-sMAXIMUM_MEMORY=41943040'])
+    self.assertContained('emcc: error: MAXIMUM_MEMORY is only meaningful with ALLOW_MEMORY_GROWTH', err)
+
   def test_dasho_invalid_dir(self):
     ret = self.expect_fail([EMCC, test_file('hello_world.c'), '-o', Path('NONEXISTING_DIRECTORY/out.js')])
     self.assertContained('specified output file (NONEXISTING_DIRECTORY%sout.js) is in a directory that does not exist' % os.path.sep, ret)