[Flang][OpenMP] Fix defaultmap(none) being overly aggressive with symbol checks (llvm#167806)

Currently we're picking up and complaining about builtin (and procedure)
symbols like null() when defaultmap(none) is set, so I've relaxed the
restriction a bit to allow for procedures and named constants to bypass
the restriction. It might be the case that we want to tighten it up
again in certain aspects in the future.

Author: agozillon

flang/lib/Semantics/resolve-directives.cpp

@@ -3054,8 +3054,13 @@ void OmpAttributeVisitor::Post(const parser::Name &name) {
       // place for the types specified.
       if (Symbol * found{currScope().FindSymbol(name.source)}) {
         // If the variable has declare target applied to it (enter or link) it
-        // is exempt from defaultmap(none) restrictions
-        if (!symbol->GetUltimate().test(Symbol::Flag::OmpDeclareTarget)) {
+        // is exempt from defaultmap(none) restrictions.
+        // We also exempt procedures and named constants from defaultmap(none)
+        // checking.
+        if (!symbol->GetUltimate().test(Symbol::Flag::OmpDeclareTarget) &&
+            !(IsProcedure(*symbol) &&
+                !semantics::IsProcedurePointer(*symbol)) &&
+            !IsNamedConstant(*symbol)) {
           auto &dMap = GetContext().defaultMap;
           for (auto defaults : dMap) {
             if (defaults.second ==

flang/test/Semantics/OpenMP/defaultmap-clause-none.f90

@@ -94,3 +94,40 @@ subroutine defaultmap_aggregate_none
         end do
     !$omp end target
 end subroutine defaultmap_aggregate_none
+
+! Verify we do not catch null in defaultmap(none)
+subroutine defaultmap_builtin_none
+    implicit none
+    integer,  pointer :: ptr(:)
+
+    !$omp target defaultmap(none) map(ptr)
+!CHECK-NOT: The DEFAULTMAP(NONE) clause requires that 'null' must be listed in a data-sharing attribute, data-mapping attribute, or is_device_ptr clause
+            ptr => null()
+    !$omp end target
+end subroutine defaultmap_builtin_none
+
+module pro
+ implicit none
+contains
+
+ function test_procedure() result(ret)
+    integer :: ret
+    ret = 1
+ end function test_procedure
+
+! Verify we do not catch a function symbol in defaultmap(none)
+! but do catch procedure pointers
+subroutine defaultmap_func_and_procedure_pointer()
+    implicit none
+    procedure(test_procedure), pointer :: f1
+    integer :: i
+
+    f1 => test_procedure
+
+    !$omp target defaultmap(none) map(i)
+!ERROR: The DEFAULTMAP(NONE) clause requires that 'f1' must be listed in a data-sharing attribute, data-mapping attribute, or is_device_ptr clause
+        i = f1()
+        i = test_procedure()
+    !$omp end target
+end subroutine defaultmap_func_and_procedure_pointer
+end module