Warn on too many parameters for Web VMs (#5119)

Fixes emscripten-core/emscripten#17988

1 files changed, 22 insertions, 0 deletions

diff --git a/test/unit/test_web_limitations.py b/test/unit/test_web_limitations.py
new file mode 100644
index 000000000..6359390f9
--- /dev/null
+++ b/test/unit/test_web_limitations.py
@@ -0,0 +1,22 @@
+import os
+
+from scripts.test import shared
+from . import utils
+
+
+class WebLimitations(utils.BinaryenTestCase):
+    def test_many_params(self):
+        """Test that we warn on large numbers of parameters, which Web VMs
+        disallow."""
+
+        params = '(param i32) ' * 1001
+        module = '''
+        (module
+         (func $foo %s
+         )
+        )
+        ''' % params
+        p = shared.run_process(shared.WASM_OPT + ['-o', os.devnull],
+                               input=module, capture_output=True)
+        self.assertIn('Some VMs may not accept this binary because it has a large number of parameters in function foo.',
+                      p.stderr)