[flang][OpenMP] Allow default(none) to access variables with PARAMETER attribute

[NimishMishra]

Summary

This patch fixes https://github.com/flang-compiler/f18-llvm-project/issues/1351. Concretely, data-sharing attributes on PARAMETER data used in a block with DEFAULT(NONE) should be ignored.

[kiranchandramohan]

flang/lib/Semantics/resolve-directives.cpp

1486

Did you notice any issue with adding this check to the outer if?

[NimishMishra]

flang/lib/Semantics/resolve-directives.cpp

1478

@kiranchandramohan If you meant if we observe errors when adding the check here, then no.

[kiranchandramohan]

flang/lib/Semantics/resolve-directives.cpp

1478

Since OpenMP-specific symbol information is not expected in the symbol for parameter constants, this might be a better position for that check.

[NimishMishra]

Shifted position of the check

[kiranchandramohan]

LGTM.

flang/lib/Semantics/resolve-directives.cpp

 }
 
 // For OpenMP constructs, check all the data-refs within the constructs
 // and adjust the symbol for each Name if necessary
 void OmpAttributeVisitor::Post(const parser::Name &name) {
   auto *symbol{name.symbol};
   if (symbol && !dirContext_.empty() && GetContext().withinConstruct) {
     if (!symbol->owner().IsDerivedType() && !symbol->has<ProcEntityDetails>() &&
         !IsObjectWithDSA(*symbol)) {
       // TODO: create a separate function to go through the rules for
       //       predetermined, explicitly determined, and implicitly
       //       determined data-sharing attributes (2.15.1.1).
       if (Symbol * found{currScope().FindSymbol(name.source)}) {
         if (symbol != found) {
           name.symbol = found; // adjust the symbol within region
-        } else if (GetContext().defaultDSA == Symbol::Flag::OmpNone) {
+        } else if (GetContext().defaultDSA == Symbol::Flag::OmpNone &&
+            !IsNamedConstant(*symbol)) {
           context_.Say(name.source,
               "The DEFAULT(NONE) clause requires that '%s' must be listed in "
               "a data-sharing attribute clause"_err_en_US,
               symbol->name());
         }
       }
     }
   } // within OpenMP construct

flang/test/Semantics/OpenMP/omp-resolve05.f90

 ! RUN: %python %S/../test_errors.py %s %flang -fopenmp
 
 ! 2.15.3 Data-Sharing Attribute Clauses
 ! 2.15.3.1 default Clause
 
 subroutine default_none()
   integer a(3)
-
+  integer, parameter :: D=10
   A = 1
   B = 2
   !$omp parallel default(none) private(c)
   !ERROR: The DEFAULT(NONE) clause requires that 'a' must be listed in a data-sharing attribute clause
   A(1:2) = 3
   !ERROR: The DEFAULT(NONE) clause requires that 'b' must be listed in a data-sharing attribute clause
   B = 4
-  C = 5
+  C = 5 + D
   !$omp end parallel
 end subroutine default_none
 
 program mm
   call default_none()
   !TODO: private, firstprivate, shared
 end