[clang] [OpenACC] Implement Sema work for OpenACC Clauses (PR #87821)

[Erich Keane via cfe-commits]

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@@ -37,6 +37,32 @@ bool diagnoseConstructAppertainment(SemaOpenACC &S, OpenACCDirectiveKind K,
   }
   return false;
 }
+
+bool doesClauseApplyToDirective(OpenACCDirectiveKind DirectiveKind,
+                                OpenACCClauseKind ClauseKind) {
+  switch (ClauseKind) {
+    // FIXME: For each clause as we implement them, we can add the
+    // 'legalization' list here.
+  default:
+    // Do nothing so we can go to the 'unimplemented' diagnostic instead.
+    return true;
+  }
+  llvm_unreachable("Invalid clause kind");
+}
+
+/// Destruct and deallocate any clauses that aren't going to be used because
+/// they don't have a Construct to attach to.
+void DestroyUnusedClauses(ASTContext &Ctx,
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erichkeane wrote:

Well, there WOULD be no 'ignoring' in codegen, as these clauses won't be added to the AST at all.  They'd be created, then just 'forgotten' if we don't add them to a construct.

https://github.com/llvm/llvm-project/pull/87821