[clang] [OpenACC] Implement beginning parts of the 'parallel' Sema impl (PR #81659)

[Alexey Bataev via cfe-commits]

================
@@ -0,0 +1,132 @@
+//===--- SemaOpenACC.cpp - Semantic Analysis for OpenACC constructs -------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file implements semantic analysis for OpenACC constructs and
+/// clauses.
+///
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/DiagnosticSema.h"
+#include "clang/Basic/OpenACCKinds.h"
+#include "clang/Sema/Sema.h"
+
+using namespace clang;
+
+namespace {
+bool DiagnoseConstructAppertainment(Sema &S, OpenACCDirectiveKind K,
+                                    SourceLocation StartLoc, bool IsStmt) {
+  switch (K) {
+  default:
+  case OpenACCDirectiveKind::Invalid:
+    // Nothing to do here, both invalid and unimplemented don't really need to
+    // do anything.
+    break;
----------------
alexey-bataev wrote:

Should it be llvm_unreachable?

https://github.com/llvm/llvm-project/pull/81659