Update comment

Author: aheejin

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -2057,7 +2057,8 @@ static void findUnwindDestinations(
       break;
     } else if (isa<CleanupPadInst>(Pad)) {
       // Stop on cleanup pads. Cleanups are always funclet entries for all known
-      // personalities.
+      // personalities except Wasm. And in Wasm this becomes a catch_all(_ref),
+      // which always catches an exception.
       UnwindDests.emplace_back(FuncInfo.getMBB(EHPadBB), Prob);
       UnwindDests.back().first->setIsEHScopeEntry();
       // In Wasm, EH scopes are not funclets