Re: [Patch, Fortran, F03] PR 40870: include formal args in backend_decl of PPCs

[Janus Weil <janus at gcc dot gnu dot org>]

Paul,

> Aahhh! ?That's because it's so good that it's invisible. ?For lesser
> mortals that can't deal with the latest technology, please find the
> diff attached.

I think your patch effectively does pretty much the same as mine (even
though mine lacks the invisibility mode ;), but your version is
probably safer against regressions, since it's guarded by an
additional check for derived->attr.proc_pointer_comp.

Btw, I found another minor flaw in my patch, concerning cases like
"procedure(integer), pointer, nopass".

Updated patch (based on Paul's version) is attached. Ok to commit
after another regtest?

Cheers,
Janus


2009-08-05  Janus Weil  <janus@gcc.gnu.org>
	    Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/40870
	* trans-types.c (gfc_get_ppc_type): Include formal args in backend_decl
	using the interface symbol.
	(gfc_get_derived_type): Prevent infinite recursion loop
	if a PPC has a derived-type formal arg.

2009-08-05  Janus Weil  <janus@gcc.gnu.org>
	    Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/40870
	* gfortran.dg/proc_ptr_comp_13.f90: Extended.



> On Tue, Aug 4, 2009 at 3:17 PM, Janus Weil<janus@gcc.gnu.org> wrote:
>> 2009/8/4 Paul Richard Thomas <paul.richard.thomas@gmail.com>:
>>>> Well, in principle you're right: Usually one should test for
>>>> TYPE_FIELDS. However, in this case I think it's not possible, because
>>>> the fields have not been built yet. Here's an example:
>>>
>>> Indeed! ?That was the idea behind the modified patch that I attached.
>>
>> Sorry, I think the attachment was missing?!?
>>
>> Cheers,
>> Janus

Index: gcc/testsuite/gfortran.dg/proc_ptr_comp_13.f90
===================================================================
--- gcc/testsuite/gfortran.dg/proc_ptr_comp_13.f90	(revision 150455)
+++ gcc/testsuite/gfortran.dg/proc_ptr_comp_13.f90	(working copy)
@@ -1,6 +1,7 @@
 ! { dg-do run }
 !
-! PR 40882: [F03] infinite recursion in gfc_get_derived_type with PPC returning derived type
+! PR 40882: [F03] infinite recursion in gfc_get_derived_type with PPC returning derived type.
+! At the same time, check that a formal argument does not cause infinite recursion (PR 40870).
 !
 ! Contributed by Janus Weil <janus@gcc.gnu.org>
 
@@ -9,6 +10,7 @@ implicit none
 type :: t
   integer :: data
   procedure(foo), pointer, nopass :: ppc
+  procedure(type(t)), pointer, nopass :: ppc2
 end type
 
 type(t) :: o,o2
@@ -16,7 +18,7 @@ type(t) :: o,o2
 o%data = 1
 o%ppc => foo
 
-o2 = o%ppc()
+o2 = o%ppc(o)
 
 if (o%data /= 1) call abort()
 if (o2%data /= 5) call abort()
@@ -25,9 +27,9 @@ if (associated(o2%ppc)) call abort()
 
 contains
 
-  function foo()
-    type(t) :: foo
-    foo%data = 5
+  function foo(arg)
+    type(t) :: foo, arg
+    foo%data = arg%data * 5
     foo%ppc => NULL()
   end function
 
Index: gcc/fortran/trans-types.c
===================================================================
--- gcc/fortran/trans-types.c	(revision 150455)
+++ gcc/fortran/trans-types.c	(working copy)
@@ -1895,16 +1895,16 @@ tree
 gfc_get_ppc_type (gfc_component* c)
 {
   tree t;
+
+  /* Explicit interface.  */
+  if (c->attr.if_source != IFSRC_UNKNOWN && c->ts.interface)
+    return build_pointer_type (gfc_get_function_type (c->ts.interface));
+
+  /* Implicit interface (only return value may be known).  */
   if (c->attr.function && !c->attr.dimension)
-    {
-      if (c->ts.type == BT_DERIVED)
-	t = c->ts.derived->backend_decl;
-      else
-	t = gfc_typenode_for_spec (&c->ts);
-    }
+    t = gfc_typenode_for_spec (&c->ts);
   else
     t = void_type_node;
-  /* TODO: Build argument list.  */
   return build_pointer_type (build_function_type (t, NULL_TREE));
 }
 
@@ -2012,8 +2012,11 @@ gfc_get_derived_type (gfc_symbol * deriv
      components' backend_decl may have not been built.  */
   if (derived->backend_decl)
     {
-      /* Its components' backend_decl have been built.  */
-      if (TYPE_FIELDS (derived->backend_decl))
+      /* Its components' backend_decl have been built or we are
+	 seeing recursion through the formal arglist of a procedure
+	 pointer component.  */
+      if (TYPE_FIELDS (derived->backend_decl)
+	    || derived->attr.proc_pointer_comp)
         return derived->backend_decl;
       else
         typenode = derived->backend_decl;