[Ada] Fix crash on access type to limited with'ed type

[Eric Botcazou <ebotcazou at adacore dot com>]

Limited with'ed types generate circularities during the translation of the FE 
trees in gigi and there is a dedicated deferring mechanism implemented in 
order to properly handle them.  The problem is that the mechanism was invoked 
only on limited with'ed types that directly point back to the main unit; we 
need to extend that to all limited with'ed types.

Tested on i586-suse-linux, applied on the mainline.


2011-03-26  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc-interface/gigi.h (finalize_from_with_types): Adjust comment.
	* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Access_Type>: Defer
	unconditionally to the end of the unit when the designated type is
	limited_with'ed.
	<all>: Rename local variable.  Attempt to un-defer types only and do it
	for limited_with'ed types as well.
	(finalize_from_with_types): Adjust comment.  Rename variable and tidy.
	* gcc-interface/trans.c (Compilation_Unit_to_gnu): Use GNAT_UNIT
	consistently and remove redundant call to finalize_from_with_types.


2011-03-26  Eric Botcazou  <ebotcazou@adacore.com>

	* gnat.dg/limited_with2.ad[sb]: New test.
	* gnat.dg/limited_with2_pkg1.ads: New helper.
	* gnat.dg/imited_with2_pkg2.ads: Likewise.


-- 
Eric Botcazou

Index: gcc-interface/decl.c
===================================================================
--- gcc-interface/decl.c	(revision 171404)
+++ gcc-interface/decl.c	(working copy)
@@ -3723,15 +3723,10 @@ gnat_to_gnu_entity (Entity_Id gnat_entit
 	   save our current definition, evaluate the actual type, and replace
 	   the tentative type we made with the actual one.  If we are to defer
 	   actually looking up the actual type, make an entry in the deferred
-	   list.  If this is from a limited with, we have to defer to the end
-	   of the current spec in two cases: first if the designated type is
-	   in the current unit and second if the access type itself is.  */
+	   list.  If this is from a limited with, we may have to defer to the
+	   end of the current unit.  */
 	if ((!in_main_unit || is_from_limited_with) && made_dummy)
 	  {
-	    bool is_from_limited_with_in_main_unit
-	      = (is_from_limited_with
-		 && (in_main_unit
-		     || In_Extended_Main_Code_Unit (gnat_entity)));
 	    tree gnu_old_desig_type
 	      = TYPE_IS_FAT_POINTER_P (gnu_type)
 		? TYPE_UNCONSTRAINED_ARRAY (gnu_type) : TREE_TYPE (gnu_type);
@@ -3762,15 +3757,14 @@ gnat_to_gnu_entity (Entity_Id gnat_entit
 	       Besides, variants of this non-dummy type might have been created
 	       along the way.  update_pointer_to is expected to properly take
 	       care of those situations.  */
-	    if (defer_incomplete_level == 0
-		&& !is_from_limited_with_in_main_unit)
+	    if (defer_incomplete_level == 0 && !is_from_limited_with)
 	      update_pointer_to (TYPE_MAIN_VARIANT (gnu_old_desig_type),
 				 gnat_to_gnu_type (gnat_desig_equiv));
 	    else
 	      {
 		struct incomplete *p = XNEW (struct incomplete);
 		struct incomplete **head
-		  = (is_from_limited_with_in_main_unit
+		  = (is_from_limited_with
 		     ? &defer_limited_with : &defer_incomplete_list);
 		p->old_type = gnu_old_desig_type;
 		p->full_type = gnat_desig_equiv;
@@ -4968,12 +4962,12 @@ gnat_to_gnu_entity (Entity_Id gnat_entit
     {
       if (defer_incomplete_list)
 	{
-	  struct incomplete *incp, *next;
+	  struct incomplete *p, *next;
 
 	  /* We are back to level 0 for the deferring of incomplete types.
 	     But processing these incomplete types below may itself require
 	     deferring, so preserve what we have and restart from scratch.  */
-	  incp = defer_incomplete_list;
+	  p = defer_incomplete_list;
 	  defer_incomplete_list = NULL;
 
 	  /* For finalization, however, all types must be complete so we
@@ -4981,14 +4975,14 @@ gnat_to_gnu_entity (Entity_Id gnat_entit
 	     referencing each other.  Process them all recursively first.  */
 	  defer_finalize_level++;
 
-	  for (; incp; incp = next)
+	  for (; p; p = next)
 	    {
-	      next = incp->next;
+	      next = p->next;
 
-	      if (incp->old_type)
-		update_pointer_to (TYPE_MAIN_VARIANT (incp->old_type),
-				   gnat_to_gnu_type (incp->full_type));
-	      free (incp);
+	      if (p->old_type)
+		update_pointer_to (TYPE_MAIN_VARIANT (p->old_type),
+				   gnat_to_gnu_type (p->full_type));
+	      free (p);
 	    }
 
 	  defer_finalize_level--;
@@ -5008,18 +5002,26 @@ gnat_to_gnu_entity (Entity_Id gnat_entit
 	}
     }
 
-  /* If we are not defining this type, see if it's in the incomplete list.
-     If so, handle that list entry now.  */
-  else if (!definition)
+  /* If we are not defining this type, see if it's on one of the lists of
+     incomplete types.  If so, handle the list entry now.  */
+  if (is_type && !definition)
     {
-      struct incomplete *incp;
+      struct incomplete *p;
 
-      for (incp = defer_incomplete_list; incp; incp = incp->next)
-	if (incp->old_type && incp->full_type == gnat_entity)
+      for (p = defer_incomplete_list; p; p = p->next)
+	if (p->old_type && p->full_type == gnat_entity)
 	  {
-	    update_pointer_to (TYPE_MAIN_VARIANT (incp->old_type),
+	    update_pointer_to (TYPE_MAIN_VARIANT (p->old_type),
 			       TREE_TYPE (gnu_decl));
-	    incp->old_type = NULL_TREE;
+	    p->old_type = NULL_TREE;
+	  }
+
+      for (p = defer_limited_with; p; p = p->next)
+	if (p->old_type && Non_Limited_View (p->full_type) == gnat_entity)
+	  {
+	    update_pointer_to (TYPE_MAIN_VARIANT (p->old_type),
+			       TREE_TYPE (gnu_decl));
+	    p->old_type = NULL_TREE;
 	  }
     }
 
@@ -5144,24 +5146,24 @@ finish_fat_pointer_type (tree record_typ
   TYPE_CONTAINS_PLACEHOLDER_INTERNAL (record_type) = 2;
 }
 
-/* Finalize any From_With_Type incomplete types.  We do this after processing
-   our compilation unit and after processing its spec, if this is a body.  */
+/* Finalize the processing of From_With_Type incomplete types.  */
 
 void
 finalize_from_with_types (void)
 {
-  struct incomplete *incp = defer_limited_with;
-  struct incomplete *next;
+  struct incomplete *p, *next;
+
+  p = defer_limited_with;
+  defer_limited_with = NULL;
 
-  defer_limited_with = 0;
-  for (; incp; incp = next)
+  for (; p; p = next)
     {
-      next = incp->next;
+      next = p->next;
 
-      if (incp->old_type != 0)
-	update_pointer_to (TYPE_MAIN_VARIANT (incp->old_type),
-			   gnat_to_gnu_type (incp->full_type));
-      free (incp);
+      if (p->old_type)
+	update_pointer_to (TYPE_MAIN_VARIANT (p->old_type),
+			   gnat_to_gnu_type (p->full_type));
+      free (p);
     }
 }
 
Index: gcc-interface/gigi.h
===================================================================
--- gcc-interface/gigi.h	(revision 171404)
+++ gcc-interface/gigi.h	(working copy)
@@ -96,8 +96,7 @@ do {					\
     mark_visited (EXP);			\
 } while (0)
 
-/* Finalize any From_With_Type incomplete types.  We do this after processing
-   our compilation unit and after processing its spec, if this is a body.  */
+/* Finalize the processing of From_With_Type incomplete types.  */
 extern void finalize_from_with_types (void);
 
 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
Index: gcc-interface/trans.c
===================================================================
--- gcc-interface/trans.c	(revision 171551)
+++ gcc-interface/trans.c	(working copy)
@@ -3785,27 +3785,23 @@ Compilation_Unit_to_gnu (Node_Id gnat_no
   gnat_pushlevel ();
 
   /* For a body, first process the spec if there is one.  */
-  if (Nkind (Unit (gnat_node)) == N_Package_Body
-      || (Nkind (Unit (gnat_node)) == N_Subprogram_Body
-	      && !Acts_As_Spec (gnat_node)))
-    {
-      add_stmt (gnat_to_gnu (Library_Unit (gnat_node)));
-      finalize_from_with_types ();
-    }
+  if (Nkind (gnat_unit) == N_Package_Body
+      || (Nkind (gnat_unit) == N_Subprogram_Body && !Acts_As_Spec (gnat_node)))
+    add_stmt (gnat_to_gnu (Library_Unit (gnat_node)));
 
   if (type_annotate_only && gnat_node == Cunit (Main_Unit))
     {
       elaborate_all_entities (gnat_node);
 
-      if (Nkind (Unit (gnat_node)) == N_Subprogram_Declaration
-	  || Nkind (Unit (gnat_node)) == N_Generic_Package_Declaration
-	  || Nkind (Unit (gnat_node)) == N_Generic_Subprogram_Declaration)
+      if (Nkind (gnat_unit) == N_Subprogram_Declaration
+	  || Nkind (gnat_unit) == N_Generic_Package_Declaration
+	  || Nkind (gnat_unit) == N_Generic_Subprogram_Declaration)
 	return;
     }
 
   process_decls (Declarations (Aux_Decls_Node (gnat_node)), Empty, Empty,
 		 true, true);
-  add_stmt (gnat_to_gnu (Unit (gnat_node)));
+  add_stmt (gnat_to_gnu (gnat_unit));
 
   /* If we can inline, generate code for all the inlined subprograms.  */
   if (optimize)

-- { dg-do compile }

with Limited_With2_Pkg2;

package body Limited_With2 is

   function Func (Val : Rec1) return Limited_With2_Pkg1.Rec2 is
   begin
      return Val.F;
   end;

end Limited_With2;

with Limited_With2_Pkg1;

package Limited_With2 is

   type Rec1 is record
     F : Limited_With2_Pkg1.Rec2;
   end record;

   function Func (Val : Rec1) return Limited_With2_Pkg1.Rec2;

end Limited_With2;

limited with Limited_With2_Pkg2;

package Limited_With2_Pkg1 is

   type Rec2 is record
      F : access Limited_With2_Pkg2.Rec3;
   end record;

end Limited_With2_Pkg1;

with Limited_With2;

package Limited_With2_Pkg2 is

   type Rec3 is record
      F : Limited_With2.Rec1;
   end record;

end Limited_With2_Pkg2;