[Patch, Fortran, OOP] PR 50960: vtables not marked as constant

[Janus Weil]

Hi all,

the attached patch marks the 'vtab' symbols as constant
(FL_PARAMETER). They are fixed objects which are initialized once and
never change.

Regtested on x86_64-unknown-linux-gnu. Ok for trunk?

Is it ok to commit without a test case? If not, any suggestions how a
good test case could look like?

Cheers,
Janus


2011-11-08  Janus Weil  <ja...@gcc.gnu.org>

        PR fortran/50960
        * class.c (gfc_find_derived_vtab): Make the vtab symbols FL_PARAMETER.
        * expr.c (gfc_simplify_expr): Prevent vtabs from being replaced with
        their value.
        * resolve.c (resolve_values): Use-associated symbols do not need to
        be resolved again.
        (resolve_fl_parameter): Make sure the symbol has a value.

Index: gcc/fortran/class.c
===================================================================
--- gcc/fortran/class.c	(revision 181107)
+++ gcc/fortran/class.c	(working copy)
@@ -428,7 +428,7 @@ gfc_find_derived_vtab (gfc_symbol *derived)
 	{
 	  gfc_get_symbol (name, ns, &vtab);
 	  vtab->ts.type = BT_DERIVED;
-	  if (gfc_add_flavor (&vtab->attr, FL_VARIABLE, NULL,
+	  if (gfc_add_flavor (&vtab->attr, FL_PARAMETER, NULL,
 	                      &gfc_current_locus) == FAILURE)
 	    goto cleanup;
 	  vtab->attr.target = 1;
Index: gcc/fortran/expr.c
===================================================================
--- gcc/fortran/expr.c	(revision 181106)
+++ gcc/fortran/expr.c	(working copy)
@@ -1883,7 +1883,8 @@ gfc_simplify_expr (gfc_expr *p, int type)
 	 initialization expression, or we want a subsection.  */
       if (p->symtree->n.sym->attr.flavor == FL_PARAMETER
 	  && (gfc_init_expr_flag || p->ref
-	      || p->symtree->n.sym->value->expr_type != EXPR_ARRAY))
+	      || p->symtree->n.sym->value->expr_type != EXPR_ARRAY)
+	  && !p->symtree->n.sym->attr.vtab)
 	{
 	  if (simplify_parameter_variable (p, type) == FAILURE)
 	    return FAILURE;
Index: gcc/fortran/resolve.c
===================================================================
--- gcc/fortran/resolve.c	(revision 181107)
+++ gcc/fortran/resolve.c	(working copy)
@@ -9514,7 +9514,7 @@ resolve_values (gfc_symbol *sym)
 {
   gfc_try t;
 
-  if (sym->value == NULL)
+  if (sym->value == NULL || sym->attr.use_assoc)
     return;
 
   if (sym->value->expr_type == EXPR_STRUCTURE)
@@ -11982,7 +11982,7 @@ resolve_fl_parameter (gfc_symbol *sym)
   /* Make sure the types of derived parameters are consistent.  This
      type checking is deferred until resolution because the type may
      refer to a derived type from the host.  */
-  if (sym->ts.type == BT_DERIVED
+  if (sym->ts.type == BT_DERIVED && sym->value
       && !gfc_compare_types (&sym->ts, &sym->value->ts))
     {
       gfc_error ("Incompatible derived type in PARAMETER at %L",