Add comments to fallsthrough cases. Also, this fixes PR1492

llvm-svn: 37405
diff --git a/llvm/lib/ExecutionEngine/ExecutionEngine.cpp b/llvm/lib/ExecutionEngine/ExecutionEngine.cpp
index 36582ee..bbddb95 100644
--- a/llvm/lib/ExecutionEngine/ExecutionEngine.cpp
+++ b/llvm/lib/ExecutionEngine/ExecutionEngine.cpp
@@ -242,16 +242,19 @@
      cerr << "Invalid type for third argument of main() supplied\n";
      abort();
    }
+   // FALLS THROUGH
   case 2:
    if (FTy->getParamType(1) != PPInt8Ty) {
      cerr << "Invalid type for second argument of main() supplied\n";
      abort();
    }
+   // FALLS THROUGH
   case 1:
    if (FTy->getParamType(0) != Type::Int32Ty) {
      cerr << "Invalid type for first argument of main() supplied\n";
      abort();
    }
+   // FALLS THROUGH
   case 0:
    if (FTy->getReturnType() != Type::Int32Ty &&
        FTy->getReturnType() != Type::VoidTy) {