[clang] [llvm] WebAssembly: Introduce ExceptionHandling::EmscriptenEH model (PR #221443)

[Heejin Ahn via cfe-commits]

================
@@ -52,13 +52,14 @@ namespace llvm {
   }
 
   enum class ExceptionHandling : int {
-    None,     ///< No exception support
-    DwarfCFI, ///< DWARF-like instruction based exceptions
-    SjLj,     ///< setjmp/longjmp based exceptions
-    ARM,      ///< ARM EHABI
-    WinEH,    ///< Windows Exception Handling
-    Wasm,     ///< WebAssembly Exception Handling
-    AIX,      ///< AIX Exception Handling
+    None,         ///< No exception support
+    DwarfCFI,     ///< DWARF-like instruction based exceptions
+    SjLj,         ///< setjmp/longjmp based exceptions
+    ARM,          ///< ARM EHABI
+    WinEH,        ///< Windows Exception Handling
+    Wasm,         ///< WebAssembly Exception Handling
+    EmscriptenEH, ///< Emscripten JavaScript-based C++ exception handling
----------------
aheejin wrote:

```suggestion
    Emscripten, ///< Emscripten JavaScript-based exception handling
```
Like Wasm, this can also later be used to handle setjmp-longjmp in C, so

https://github.com/llvm/llvm-project/pull/221443