From 6d2d73059fda5a63f2b34a9482acc0445e0956a4 Mon Sep 17 00:00:00 2001
From: Tim Keith <tkeith@nvidia.com>
Date: Wed, 5 Aug 2020 18:03:40 -0700
Subject: [PATCH] [flang] Fix compilation warning in
 check-directive-structure.h

Clang 9 gets the following warning after revision `D85104`.
```
../../flang/lib/Semantics/check-directive-structure.h:36:7: error: 'Fortran::semantics::DirectiveStructureChecker<llvm::omp::Directive, llvm::omp::Clause, Fortran::parser::OmpClause, 77>' has virtual functions but non-virtual destructor [-Werror,-Wnon-virtual-dtor]
```

The fix is the make the destructor virtual. Neither it nor the
constructor need to be public, so make them protected.

Differential Revision: https://reviews.llvm.org/D85383
---
 flang/lib/Semantics/check-directive-structure.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/flang/lib/Semantics/check-directive-structure.h b/flang/lib/Semantics/check-directive-structure.h
index a5de0564677cf..6755e475832ac 100644
--- a/flang/lib/Semantics/check-directive-structure.h
+++ b/flang/lib/Semantics/check-directive-structure.h
@@ -34,13 +34,13 @@ template <typename C, std::size_t ClauseEnumSize> struct DirectiveClauses {
 // typename PC is the parser class defined in parse-tree.h for the clauses.
 template <typename D, typename C, typename PC, std::size_t ClauseEnumSize>
 class DirectiveStructureChecker : public virtual BaseChecker {
-public:
+protected:
   DirectiveStructureChecker(SemanticsContext &context,
       std::unordered_map<D, DirectiveClauses<C, ClauseEnumSize>>
           directiveClausesMap)
       : context_{context}, directiveClausesMap_(directiveClausesMap) {}
+  virtual ~DirectiveStructureChecker() {}
 
-protected:
   struct DirectiveContext {
     DirectiveContext(parser::CharBlock source, D d)
         : directiveSource{source}, directive{d} {}