exp_dbug.ads (Packed Array Encoding): Document the new encoding for the unconstrained case.

* exp_dbug.ads (Packed Array Encoding): Document the new encoding for
	the unconstrained case.
	* gcc-interfaces/decl.c (gnat_to_gnu_entity) <E_Array_Type>: Implement
	the encoding.  Do not give a name to the pointer type to the XUT type.
	* gcc-interfaces/utils.c (gnat_pushdecl): Propagate DECL_ORIGINAL_TYPE
	for fat pointer types, if any.  Make sure DECL_ARTIFICIAL is cleared
	on nodes with DECL_ORIGINAL_TYPE set.
	(update_pointer_to): Set DECL_ORIGINAL_TYPE to the original pointer
	for fat pointer types.  Make sure DECL_ARTIFICIAL is cleared.

From-SVN: r151697

gcc/ada/ChangeLog

@@ -1,3 +1,15 @@
+2009-09-14  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* exp_dbug.ads (Packed Array Encoding): Document the new encoding for
+	the unconstrained case.
+	* gcc-interfaces/decl.c (gnat_to_gnu_entity) <E_Array_Type>: Implement
+	the encoding.  Do not give a name to the pointer type to the XUT type.
+	* gcc-interfaces/utils.c (gnat_pushdecl): Propagate DECL_ORIGINAL_TYPE
+	for fat pointer types, if any.  Make sure DECL_ARTIFICIAL is cleared
+	on nodes with DECL_ORIGINAL_TYPE set.
+	(update_pointer_to): Set DECL_ORIGINAL_TYPE to the original pointer
+	for fat pointer types.  Make sure DECL_ARTIFICIAL is cleared.
+
 2009-09-14  Richard Henderson  <rth@redhat.com>
 
 	* gcc-interface/misc.c (gnat_init_gcc_eh): Don't call

gcc/ada/exp_dbug.ads

@@ -1094,8 +1094,8 @@ package Exp_Dbug is
    -- Packed Array Encoding --
    ---------------------------
 
-   --  For every packed array, two types are created, and both appear in
+   --  For every constrained packed array, two types are created, and both
-   --  the debugging output.
+   --  appear in the debugging output:
 
    --    The original declared array type is a perfectly normal array type,
    --    and its index bounds indicate the original bounds of the array.
@@ -1110,12 +1110,27 @@ package Exp_Dbug is
    --    ttt___XPnnn
 
    --  where
+
    --    ttt is the name of the original declared array
    --    nnn is the component size in bits (1-31)
 
-   --  When the debugger sees that an object is of a type that is encoded
+   --  When the debugger sees that an object is of a type that is encoded in
-   --  in this manner, it can use the original type to determine the bounds,
+   --  this manner, it can use the original type to determine the bounds and
-   --  and the component size to determine the packing details.
+   --  the component type, and the component size to determine the packing
+   --  details.
+
+   --  For an unconstrained packed array, the corresponding packed array type
+   --  is neither used in the generated code nor for debugging information,
+   --  only the original type is used. In order to convey the packing in the
+   --  debugging information, the compiler generates the associated fat- and
+   --  thin-pointer types (see the Pointers to Unconstrained Array section
+   --  below) using the name of the corresponding packed array type as the
+   --  base name, i.e. ttt___XPnnn___XUP and ttt___XPnnn___XUT respectively.
+
+   --  When the debugger sees that an object is of a type that is encoded in
+   --  this manner, it can use the type of the fields to determine the bounds
+   --  and the component type, and the component size to determine the packing
+   --  details.
 
    -------------------------------------------
    -- Packed Array Representation in Memory --
@@ -1257,6 +1272,7 @@ package Exp_Dbug is
    --      fat-pointer type whose name is "arr___XUP", where "arr" is the name
    --      of the array type, and use it to represent the array type itself in
    --      the debugging information.
+
    --      For each pointer to this unconstrained array type, the compiler will
    --      generate a typedef that points to the above "arr___XUP" fat-pointer
    --      type. As a consequence, when it comes to fat-pointer types:

gcc/ada/gcc-interface/decl.c

@@ -1782,7 +1782,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
     case E_String_Type:
     case E_Array_Type:
       {
-	Entity_Id gnat_index;
+	Entity_Id gnat_index, gnat_name;
 	const bool convention_fortran_p
 	  = (Convention (gnat_entity) == Convention_Fortran);
 	const int ndim = Number_Dimensions (gnat_entity);
@@ -2066,8 +2066,13 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 			  tem, NULL, !Comes_From_Source (gnat_entity),
 			  debug_info_p, gnat_entity);
 
-	/* Give the fat pointer type a name.  */
+	/* Give the fat pointer type a name.  If this is a packed type, tell
-	create_type_decl (create_concat_name (gnat_entity, "XUP"),
+	   the debugger how to interpret the underlying bits.  */
+	if (Present (Packed_Array_Type (gnat_entity)))
+	  gnat_name = Packed_Array_Type (gnat_entity);
+	else
+	  gnat_name = gnat_entity;
+	create_type_decl (create_concat_name (gnat_name, "XUP"),
 			  gnu_fat_type, NULL, true,
 			  debug_info_p, gnat_entity);
 
@@ -2075,16 +2080,11 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
           record type for the object and its template with the field offsets
           shifted to have the template at a negative offset.  */
 	tem = build_unc_object_type (gnu_template_type, tem,
-				     create_concat_name (gnat_entity, "XUT"));
+				     create_concat_name (gnat_name, "XUT"));
 	shift_unc_components_for_thin_pointers (tem);
 
 	SET_TYPE_UNCONSTRAINED_ARRAY (tem, gnu_type);
 	TYPE_OBJECT_RECORD_TYPE (gnu_type) = tem;
-
-	/* Give the thin pointer type a name.  */
-	create_type_decl (create_concat_name (gnat_entity, "XUX"),
-			  build_pointer_type (tem), NULL, true,
-			  debug_info_p, gnat_entity);
       }
       break;
 

gcc/ada/gcc-interface/utils.c

@@ -495,8 +495,12 @@ gnat_pushdecl (tree decl, Node_Id gnat_node)
 	  TYPE_NAME (tt) = decl;
 	  TREE_USED (tt) = TREE_USED (t);
 	  TREE_TYPE (decl) = tt;
-	  DECL_ORIGINAL_TYPE (decl) = t;
+	  if (DECL_ORIGINAL_TYPE (TYPE_NAME (t)))
+	    DECL_ORIGINAL_TYPE (decl) = DECL_ORIGINAL_TYPE (TYPE_NAME (t));
+	  else
+	    DECL_ORIGINAL_TYPE (decl) = t;
 	  t = NULL_TREE;
+	  DECL_ARTIFICIAL (decl) = 0;
 	}
       else if (DECL_ARTIFICIAL (TYPE_NAME (t)) && !DECL_ARTIFICIAL (decl))
 	;
@@ -3665,6 +3669,18 @@ update_pointer_to (tree old_type, tree new_type)
       TYPE_POINTER_TO (new_type) = TYPE_REFERENCE_TO (new_type)
 	= TREE_TYPE (new_type) = ptr;
 
+      /* And show the original pointer NEW_PTR to the debugger.  This is the
+	 counterpart of the equivalent processing in gnat_pushdecl when the
+	 unconstrained array type is frozen after access types to it.  Note
+	 that update_pointer_to can be invoked multiple times on the same
+	 couple of types because of the type variants.  */
+      if (TYPE_NAME (ptr)
+	  && TREE_CODE (TYPE_NAME (ptr)) == TYPE_DECL
+	  && !DECL_ORIGINAL_TYPE (TYPE_NAME (ptr)))
+	{
+	  DECL_ORIGINAL_TYPE (TYPE_NAME (ptr)) = new_ptr;
+	  DECL_ARTIFICIAL (TYPE_NAME (ptr)) = 0;
+	}
       for (var = TYPE_MAIN_VARIANT (ptr); var; var = TYPE_NEXT_VARIANT (var))
 	SET_TYPE_UNCONSTRAINED_ARRAY (var, new_type);