[clang] [flang] [llvm] [OpenMP] Add parser/semantic support for dyn_groupprivate clause (PR #152651)

[Alexey Bataev via cfe-commits]

================
@@ -4008,6 +4009,82 @@ OMPClause *Parser::ParseOpenMPSingleExprWithArgClause(OpenMPDirectiveKind DKind,
       Arg.push_back(OMPC_GRAINSIZE_unknown);
       KLoc.emplace_back();
     }
+  } else if (Kind == OMPC_dyn_groupprivate) {
+    enum { SimpleModifier, ComplexModifier, NumberOfModifiers };
+    Arg.resize(NumberOfModifiers);
+    KLoc.resize(NumberOfModifiers);
+    Arg[SimpleModifier] = OMPC_DYN_GROUPPRIVATE_unknown;
+    Arg[ComplexModifier] = OMPC_DYN_GROUPPRIVATE_FALLBACK_unknown;
+
+    auto consumeModifier = [&]() {
+      unsigned Type = NumberOfModifiers;
+      unsigned Modifier;
+      SourceLocation Loc;
+      if (!Tok.isAnnotation() && PP.getSpelling(Tok) == "fallback" &&
+          NextToken().is(tok::l_paren)) {
+        ConsumeToken();
+        BalancedDelimiterTracker ParenT(*this, tok::l_paren, tok::r_paren);
+        ParenT.consumeOpen();
+
+        Modifier = getOpenMPSimpleClauseType(
+            Kind, Tok.isAnnotation() ? "" : PP.getSpelling(Tok), getLangOpts());
+        if (Modifier <= OMPC_DYN_GROUPPRIVATE_FALLBACK_unknown ||
+            Modifier >= OMPC_DYN_GROUPPRIVATE_FALLBACK_last) {
+          Diag(Tok.getLocation(), diag::err_expected)
+              << "'abort', 'null' or 'default_mem' in fallback modifier";
+          SkipUntil(tok::r_paren);
+          return std::make_tuple(Type, Modifier, Loc);
+        }
+        Type = ComplexModifier;
+        Loc = Tok.getLocation();
+        if (Tok.isNot(tok::r_paren) && Tok.isNot(tok::comma) &&
+            Tok.isNot(tok::annot_pragma_openmp_end))
+          ConsumeAnyToken();
+        ParenT.consumeClose();
+      } else {
+        Modifier = getOpenMPSimpleClauseType(
+            Kind, Tok.isAnnotation() ? "" : PP.getSpelling(Tok), getLangOpts());
+        if (Modifier < OMPC_DYN_GROUPPRIVATE_unknown) {
+          Type = SimpleModifier;
+          Loc = Tok.getLocation();
+          if (Tok.isNot(tok::r_paren) && Tok.isNot(tok::comma) &&
+              Tok.isNot(tok::annot_pragma_openmp_end))
+            ConsumeAnyToken();
+        }
+      }
+      return std::make_tuple(Type, Modifier, Loc);
+    };
+
+    auto saveModifier = [&](unsigned Type, unsigned Modifier,
----------------
alexey-bataev wrote:

```suggestion
    auto SaveModifier = [&](unsigned Type, unsigned Modifier,
```

https://github.com/llvm/llvm-project/pull/152651