[clang] [WebAssembly,clang] Add __builtin_wasm_test_function_pointer_signature (PR #150201)

[Hood Chatham via cfe-commits]

================
@@ -227,6 +227,53 @@ bool SemaWasm::BuiltinWasmTableCopy(CallExpr *TheCall) {
   return false;
 }
 
+bool SemaWasm::BuiltinWasmTestFunctionPointerSignature(CallExpr *TheCall) {
+  if (SemaRef.checkArgCount(TheCall, 1))
+    return true;
+
+  Expr *FuncPtrArg = TheCall->getArg(0);
+  QualType ArgType = FuncPtrArg->getType();
+
+  // Check that the argument is a function pointer
+  const PointerType *PtrTy = ArgType->getAs<PointerType>();
+  if (!PtrTy) {
+    return Diag(FuncPtrArg->getBeginLoc(),
+                diag::err_typecheck_expect_function_pointer)
+           << ArgType << FuncPtrArg->getSourceRange();
+  }
+
+  const FunctionProtoType *FuncTy =
+      PtrTy->getPointeeType()->getAs<FunctionProtoType>();
+  if (!FuncTy) {
+    return Diag(FuncPtrArg->getBeginLoc(),
+                diag::err_typecheck_expect_function_pointer)
+           << ArgType << FuncPtrArg->getSourceRange();
+  }
+
+  // Check that the function pointer doesn't use reference types
----------------
hoodmane wrote:

It's enough here but the LLVM intrinsic doesn't handle them yet. It shouldn't be too hard to support but it seemed tricky enough that I thought it would be better to leave to a follow-up.

https://github.com/llvm/llvm-project/pull/150201