[clang] [WebAssembly] Refactor Wasm EH/SjLj error checking (PR #122466)

[Heejin Ahn via cfe-commits]

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@@ -120,26 +120,33 @@
 // RUN:   | FileCheck -check-prefix=EMSCRIPTEN_EH_ALLOWED_WO_ENABLE %s
 // EMSCRIPTEN_EH_ALLOWED_WO_ENABLE: invalid argument '-mllvm -emscripten-cxx-exceptions-allowed' only allowed with '-mllvm -enable-emscripten-cxx-exceptions'
 
-// '-fwasm-exceptions' sets +exception-handling, -multivalue, -reference-types
-// and '-mllvm -wasm-enable-eh'
+// '-fwasm-exceptions' sets +exception-handling, -multivalue, -reference-types,
+// "-exception-model=wasm", and '-mllvm -wasm-enable-eh'
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aheejin wrote:

`-exception-model=wasm` is also set in
https://github.com/llvm/llvm-project/blob/9c85cdec4ad29389c27cc2372d45f73d1ca8053a/clang/lib/Driver/ToolChains/Clang.cpp#L7469-L7470
which is the reason we set this only for Wasm SjLj and not Wasm EH here. But now `EnableFeaturesForWasmEHSjLj` includes it so it is set for both, which I think is harmless anyway.

https://github.com/llvm/llvm-project/pull/122466