[flang][lowering] Do not instantiate component symbols used in spec expr

[jeanPerier]

Summary

Lowering analyse specification expressions in order to create order the
symbol instantiations in the IR (If symbol B is used in the
specification expression of A, symbol B must be instantiated first).

This analysis was mistakenly collecting component symbols used in
component references inside specification expressions, which led
lowering to instantiate component symbols as if they were local
objects.

This patch prevents collecting component symbols during this analysis.

[vzakhari]

Thank you!

flang/lib/Lower/PFTBuilder.cpp

int analyze(const semantics::Symbol &sym) {
     const bool isProcedurePointerOrDummy =
         semantics::IsProcedurePointer(sym) ||
         (semantics::IsProcedure(sym) && IsDummy(sym));
     // A procedure argument in a subprogram with multiple entry points might
     // need a layeredVarList entry to trigger creation of a symbol map entry
     // in some cases. Non-dummy procedures don't.
     if (semantics::IsProcedure(sym) && !isProcedurePointerOrDummy)
       return 0;
+    // Derived type component symbols may be collected by "CollectSymbols"
+    // below when processing something like "real :: x(derived%component)". The
+    // symbol "component" has "ObjectEntityDetails", but it should not be
+    // instantiated: it is is part of "derived" that should be the only one to
+    // be instantiated.
+    if (sym.owner().IsDerivedType())
+      return 0;
+
     semantics::Symbol ultimate = sym.GetUltimate();
     if (const auto *details =
             ultimate.detailsIf<semantics::NamelistDetails>()) {
       // handle namelist group symbols
       for (const semantics::SymbolRef &s : details->objects())
         analyze(s);
       return 0;
     }

flang/test/Lower/HLFIR/convert-variable.f90

 ! CHECK:  %[[VAL_1:.*]] = hlfir.declare %[[VAL_0]] {fortran_attrs = #fir.var_attrs<intent_out>, uniq_name = "_QFscalar_numeric_attributes_4Ex"} : (!fir.ref<!fir.logical<8>>) -> (!fir.ref<!fir.logical<8>>, !fir.ref<!fir.logical<8>>)
 
 subroutine scalar_numeric_parameter()
   integer, parameter :: p = 42
 end subroutine
 ! CHECK-LABEL: func.func @_QPscalar_numeric_parameter() {
 ! CHECK:  %[[VAL_0:.*]] = fir.address_of(@_QFscalar_numeric_parameterECp) : !fir.ref<i32>
 ! CHECK:  %[[VAL_1:.*]] = hlfir.declare %[[VAL_0]] {fortran_attrs = #fir.var_attrs<parameter>, uniq_name = "_QFscalar_numeric_parameterECp"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+
+subroutine test_component_in_spec_expr(x, derived)
+  type t
+    integer :: component
+  end type
+  type(t) :: derived
+  ! Test that we do not try to instantiate "component" just because
+  ! its symbol appears in a specification expression.
+  real :: x(derived%component)
+end subroutine
+! CHECK-LABEL: func.func @_QPtest_component_in_spec_expr(
+! CHECK-NOT: alloca
+! CHECK: return