[clang] [llvm] [WebAssembly] Implement an alternative translation for -wasm-enable-sjlj (PR #84137)

[Sam Clegg via cfe-commits]

================
@@ -999,25 +1002,42 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runOnModule(Module &M) {
       // Register __wasm_longjmp function, which calls __builtin_wasm_longjmp.
       FunctionType *FTy = FunctionType::get(
           IRB.getVoidTy(), {Int8PtrTy, IRB.getInt32Ty()}, false);
-      WasmLongjmpF = getEmscriptenFunction(FTy, "__wasm_longjmp", &M);
+      if (EnableWasmAltSjLj) {
+        WasmLongjmpF = getEmscriptenFunction(FTy, "__wasm_sjlj_longjmp", &M);
+      } else {
+        WasmLongjmpF = getEmscriptenFunction(FTy, "__wasm_longjmp", &M);
+      }
       WasmLongjmpF->addFnAttr(Attribute::NoReturn);
     }
 
     if (SetjmpF) {
       Type *Int8PtrTy = IRB.getPtrTy();
       Type *Int32PtrTy = IRB.getPtrTy();
       Type *Int32Ty = IRB.getInt32Ty();
-      // Register saveSetjmp function
-      FunctionType *SetjmpFTy = SetjmpF->getFunctionType();
-      FunctionType *FTy = FunctionType::get(
-          Int32PtrTy,
-          {SetjmpFTy->getParamType(0), Int32Ty, Int32PtrTy, Int32Ty}, false);
-      SaveSetjmpF = getEmscriptenFunction(FTy, "saveSetjmp", &M);
 
       // Register testSetjmp function
----------------
sbc100 wrote:

This comment should probably be moved to line 1027 and line 1037?

https://github.com/llvm/llvm-project/pull/84137