After emscripten-core#10741, we are still getting non-unique function pointer indexes in fastcomp because we are doing a matching the on the stubs instead of the wasm function wrapper.

In this change, we get the actual function wrapper and pass it into addFunction() so that addFunction can use this to compare with the function wrapper gotten from the wasm table.

Author: Mintyboi

emscripten.py

@@ -1559,14 +1559,19 @@ def check(extern):
       fullname = "fp$" + extern
       key = '%sModule["%s"]' % (side, fullname)
       asm_setup += '''\
-    var %s = function() {
-      if (!%s) { %s
-        var fid = addFunction(%sModule["%s"] || %s, "%s");
-        %s = fid;
+    var %(fullname)s = function() {
+        if (!%(key)s) { %(assetMsg)s
+        // Use the original wasm function itself, for the table, from the main module.
+        var func = Module['asm']['%(barename)s'];
+        if (!func) {
+          func = %(side)sModule["%(barename)s"] || %(barename)s;
+        }
+        var fid = addFunction(func, "%(sig)s");
+        %(key)s = fid;
       }
-      return %s;
+      return %(key)s;
     }
-    ''' % (fullname, key, check(barename), side, barename, barename, sig, key, key)
+    ''' % {'fullname': fullname, 'key': key, 'assetMsg': check(barename), 'side': side, 'barename': barename, 'sig': sig}
 
   asm_setup += create_invoke_wrappers(invoke_function_names)
   asm_setup += setup_function_pointers(function_table_sigs)