[compiler-rt] [lld] [llvm] [WebAssembly] Require tags for Wasm EH and Wasm SJLJ to be defined externally (PR #159143)

[Sam Clegg via llvm-commits]

================
@@ -0,0 +1,26 @@
+//===-- __cpp_exception.S - Implement __cpp_exception.S -------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements __cpp_exception which LLVM uses to implement exception
+// handling when Wasm EH is enabled.
+//
+//===----------------------------------------------------------------------===//
+
+#ifdef __wasm_exception_handling__
----------------
sbc100 wrote:

Maybe I should revert that part of this PR?   Both emscripten and wasi-sdk can take care of defining these symbols in their runtime support code.

https://github.com/llvm/llvm-project/pull/159143