decl.c (gnat_to_gnu_entity): Manually mark the top of the renamed expression of…

decl.c (gnat_to_gnu_entity): Manually mark the top of the renamed expression of a full renaming at toplevel.

2007-04-20  Eric Botcazou  <ebotcazou@adacore.com>
	    Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
	    Olivier Hainque  <hainque@adacore.com>

	* decl.c (gnat_to_gnu_entity) <object>: Manually mark the top of the
	renamed expression of a full renaming at toplevel.
	(gnat_to_gnu_entity, case object): If not defining, do not look inside
	the values the constant is initialized to if it is an N_Allocator.
	(gnat_to_gnu_entity) <E_Array_Subtype>: Manually mark the top of the
	TYPE_SIZE_UNIT of inner types after the stride is elaborated.
	(make_aligning_type): Accept an extra ROOM argument for storage to be
	made available before the aligned field, and an extra BASE_ALIGN
	argument for callers to pass the alignment guaranteed to be honored for
	the whole aligning object. Avoid call to finish_record_type, which only
	interferes with the sizes we want to set.
	(gnat_to_gnu_entity) <E_Variable>: Pass the required extra arguments to
	make_aligning_type for super-aligned objects on stack.
	(components_to_record): Pass the adjusted size of the type when creating
	fields in the qualified union for the variant part.
	(gnat_substitute_in_type): Copy TYPE_USER_ALIGN.
	(gnat_to_gnu_entity, case E_Signed_Integer_Subtype): Likewise for
	packed array type.
	(maybe_pad_type): Set TYPE_USER_ALIGN.
	(make_aligning_type): Likewise.
	ALIGN argument is unsigned int.
	(gnat_to_gnu_entity, case E_Function): Back annotate return mechanism.
	(gnat_to_gnu_param): Likewise, for parameters.
	(gnat_to_gnu_entity) <object>: Always instantiate the renaming object
	if it is constant and stems from a function call.
	(gnat_to_gnu_entity) <E_Record_Type>: Set packed to -2 if the alignment
	of the record is specified.  Adjust accordingly.
	(adjust_packed): New static function.
	(gnat_to_gnu_field): Use it to adjust the packedness setting.
	(components_to_record): Likewise.
	(gnat_to_gnu_entity) <object>: Do not test the renamed expression for
	side-effects if the object is deemed constant.
	(gnat_to_gnu_entity) <E_Array_Type>: Create a name for the fat pointer
	type instead of merely finalizing it.  Tidy.
	<E_Access_Subprogram_Type>: Retrieve the type from the TYPE_DECL.
	<E_Access_Type>: Likewise.
	(defer_debug_incomplete_list): Rename to defer_finalize_list.
	(defer_debug_level): Delete.
	(gnat_to_gnu_entity) <debug_deferred>: Likewise
	<E_Array_Type>: Call rest_of_record_type_compilation on the fat pointer
	type.
	<E_Record_Type>: Do not explicitly defer finalizing the type.
	Adjust for write_record_type_debug_info renaming.
	<E_Subprogram_Type>: Likewise.
	Finalize deferred types right after deferred incomplete types are
	expanded.
	(rest_of_type_decl_compilation): New global function.
	(components_to_record): Rename defer_debug parameter to do_not_finalize.
	(components_to_record): Propagate the packedness to the fields of the
	qualified union type if there is a variant part.
	(gnat_to_gnu_entity) <E_Array_Type>: Use new function
	instead of inline code to adjust the XUT field offsets.
	(gnat_to_gnu_entity): Adjust for new prototype of finish_record_type.
	<E_Record_Subtype>: Do not let finish_record_type compute the sizes
	and write the debug info if the type derives from a discriminated one.
	(gnat_to_gnu_entity) <E_Array_Type>: Adjust call to create_index_type.
	<E_Array_Subtype>: Likewise.
	<E_String_Literal_Subtype>: Likewise.
	(gnat_to_gnu_entity): Set TYPE_USER_ALIGN on types only if they have
	an alignment clause.
	(maybe_pad_type): Update ORIG_SIZE to the minimum required to meet ALIGN
	before giving warning.
	(prepend_one_attribute_to): New function, helper to prepend an attribute
	to an attribute list.
	(gnat_to_gnu_entity) <E_Procedure>: Use it.
	(prepend_attributes): Likewise.
	(gnat_to_gnu_entity) <E_Variable>: Use constants of the proper type.
	<E_Array_Type>: Declare the padding type for the element type, if any.
	<E_Array_Subtype>: Likewise.
	(defer_limited_with): New variable.
	(Gigi_Equivalent_Type): New function.
	(gnat_to_gnu_entity): Use it at start and use result throughout.
	(gnat_to_gnu_entity, case E_Access_Type): Rework to use
	Gigi_Equivalent_Type, support Limited_With, allow two levels of
	indirection, precompute if unconstrained array to simplify logic, and
	use defer_limited_with to defer elaboration of some types from limited
	with.
	(finalize_from_with_types): New function.

From-SVN: r125370

gcc/ada/decl.c

@@ -64,22 +64,30 @@
 #define Has_Stdcall_Convention(E) (0)
 #endif
 
-/* These two variables are used to defer recursively expanding incomplete
-   types while we are processing a record or subprogram type.  */
-
-static int defer_incomplete_level = 0;
-static struct incomplete
+struct incomplete
 {
   struct incomplete *next;
   tree old_type;
   Entity_Id full_type;
-} *defer_incomplete_list = 0;
+};
+
+/* These variables are used to defer recursively expanding incomplete types
+   while we are processing an array, a record or a subprogram type.  */
+static int defer_incomplete_level = 0;
+static struct incomplete *defer_incomplete_list;
 
-/* These two variables are used to defer emission of debug information for
-   nested incomplete record types  */
+/* This variable is used to delay expanding From_With_Type types until the
+   end of the spec.  */
+static struct incomplete *defer_limited_with;
 
-static int defer_debug_level = 0;
-static tree defer_debug_incomplete_list;
+/* These variables are used to defer finalizing types.  The element of the
+   list is the TYPE_DECL associated with the type.  */
+static int defer_finalize_level = 0;
+static VEC (tree,heap) *defer_finalize_list;
+
+/* A hash table used to cache the result of annotate_value.  */
+static GTY ((if_marked ("tree_int_map_marked_p"),
+	     param_is (struct tree_int_map))) htab_t annotate_value_cache;
 
 /* A hash table used as to cache the result of annotate_value.  */
 static GTY ((if_marked ("tree_int_map_marked_p"), param_is (struct tree_int_map)))
@@ -88,6 +96,8 @@ static GTY ((if_marked ("tree_int_map_marked_p"), param_is (struct tree_int_map)
 static void copy_alias_set (tree, tree);
 static tree substitution_list (Entity_Id, Entity_Id, tree, bool);
 static bool allocatable_size_p (tree, bool);
+static void prepend_one_attribute_to (struct attrib **,
+				      enum attr_type, tree, tree, Node_Id);
 static void prepend_attributes (Entity_Id, struct attrib **);
 static tree elaborate_expression (Node_Id, Entity_Id, tree, bool, bool, bool);
 static bool is_variable_size (tree);
@@ -95,10 +105,11 @@ static tree elaborate_expression_1 (Node_Id, Entity_Id, tree, tree,
 				    bool, bool);
 static tree make_packable_type (tree);
 static tree gnat_to_gnu_field (Entity_Id, tree, int, bool);
+static tree gnat_to_gnu_param (Entity_Id, Mechanism_Type, Entity_Id, bool,
+			       bool *);
 static bool same_discriminant_p (Entity_Id, Entity_Id);
 static void components_to_record (tree, Node_Id, tree, int, bool, tree *,
 				  bool, bool, bool, bool);
-static int compare_field_bitpos (const PTR, const PTR);
 static Uint annotate_value (tree);
 static void annotate_rep (Entity_Id, tree);
 static tree compute_field_positions (tree, tree, tree, tree, unsigned int);
@@ -147,6 +158,7 @@ gnat_to_gnu_type (Entity_Id gnat_entity)
 tree
 gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 {
+  Entity_Id gnat_equiv_type = Gigi_Equivalent_Type (gnat_entity);
   tree gnu_entity_id;
   tree gnu_type = NULL_TREE;
   /* Contains the gnu XXXX_DECL tree node which is equivalent to the input
@@ -157,8 +169,6 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
   bool saved = false;
   /* Nonzero if we incremented defer_incomplete_level.  */
   bool this_deferred = false;
-  /* Nonzero if we incremented defer_debug_level.  */
-  bool debug_deferred = false;
   /* Nonzero if we incremented force_global.  */
   bool this_global = false;
   /* Nonzero if we should check to see if elaborated during processing.  */
@@ -331,27 +341,25 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	  break;
 	}
 
-      /* If we have an external constant that we are not defining,
-	 get the expression that is was defined to represent.  We
-	 may throw that expression away later if it is not a
-	 constant.
-         Do not retrieve the expression if it is an aggregate, because
-         in complex instantiation contexts it may not be expanded  */
-
+      /* If we have an external constant that we are not defining, get the
+	 expression that is was defined to represent.  We may throw that
+	 expression away later if it is not a constant.  Do not retrieve the
+	 expression if it is an aggregate or allocator, because in complex
+	 instantiation contexts it may not be expanded  */
       if (!definition
 	  && Present (Expression (Declaration_Node (gnat_entity)))
 	  && !No_Initialization (Declaration_Node (gnat_entity))
 	  && (Nkind (Expression (Declaration_Node (gnat_entity)))
-	      != N_Aggregate))
+	      != N_Aggregate)
+	  && (Nkind (Expression (Declaration_Node (gnat_entity)))
+	      != N_Allocator))
 	gnu_expr = gnat_to_gnu (Expression (Declaration_Node (gnat_entity)));
 
       /* Ignore deferred constant definitions; they are processed fully in the
-	 front-end.  For deferred constant references, get the full
-         definition.  On the other hand, constants that are renamings are
-	 handled like variable renamings.  If No_Initialization is set, this is
-	 not a deferred constant but a constant whose value is built
-	 manually.  */
-
+	 front-end.  For deferred constant references get the full definition.
+	 On the other hand, constants that are renamings are handled like
+	 variable renamings.  If No_Initialization is set, this is not a
+	 deferred constant but a constant whose value is built manually.  */
       if (definition && !gnu_expr
 	  && !No_Initialization (Declaration_Node (gnat_entity))
 	  && No (Renamed_Object (gnat_entity)))
@@ -458,7 +466,6 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	       type and we have an Original_Record_Component, use it.
 	       This is a workaround for major problems in protected type
 	       handling.  */
-
 	    Entity_Id Scop = Scope (Scope (gnat_entity));
 	    if ((Is_Protected_Type (Scop)
 		 || (Is_Private_Type (Scop)
@@ -553,8 +560,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	    gcc_assert (Present (Alignment (gnat_entity)));
 	    align = validate_alignment (Alignment (gnat_entity), gnat_entity,
 					TYPE_ALIGN (gnu_type));
-	    gnu_type = maybe_pad_type (gnu_type, NULL_TREE, align,
-				       gnat_entity, "PAD", 0, definition, 1);
+	    gnu_type = maybe_pad_type (gnu_type, NULL_TREE, align, gnat_entity,
+				       "PAD", false, definition, true);
 	  }
 
 	/* If we are defining the object, see if it has a Size value and
@@ -736,9 +743,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 		     (TYPE_SIZE (TREE_TYPE (TYPE_FIELDS (gnu_type)))))))
 	  gnu_expr = convert (gnu_type, gnu_expr);
 
-	/* See if this is a renaming, and handle appropriately depending on
-	   what is renamed and in which context.  There are three major
-	   cases:
+	/* See if this is a renaming and handle appropriately depending on
+	   what is renamed and in which context.  There are three cases:
 
 	   1/ This is a constant renaming and we can just make an object
 	      with what is renamed as its initial value,
@@ -746,11 +752,12 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	   2/ We can reuse a stabilized version of what is renamed in place
 	      of the renaming,
 
-	   3/ If neither 1 or 2 applies, we make the renaming entity a constant
-              pointer to what is being renamed.  */
-
+	   3/ If neither 1 nor 2 applies, we make the renaming entity a
+	      constant pointer to what is being renamed.  */
 	if (Present (Renamed_Object (gnat_entity)))
 	  {
+	    bool create_normal_object = false;
+
 	    /* If the renamed object had padding, strip off the reference
 	       to the inner object and reset our type.  */
 	    if (TREE_CODE (gnu_expr) == COMPONENT_REF
@@ -767,18 +774,33 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	       object whose initial value is what is being renamed.  We cannot
 	       do this if the type is unconstrained or class-wide.  */
 	    if (const_flag
-		&& !TREE_SIDE_EFFECTS (gnu_expr)
 		&& TREE_CODE (gnu_type) != UNCONSTRAINED_ARRAY_TYPE
-		&& TYPE_MODE (gnu_type) != BLKmode
-		&& Ekind (Etype (gnat_entity)) != E_Class_Wide_Type
-                && !Is_Array_Type (Etype (gnat_entity)))
-	      ;
+		&& Ekind (Etype (gnat_entity)) != E_Class_Wide_Type)
+	      {
+		/* However avoid creating large objects...  */
+		if (TYPE_MODE (gnu_type) != BLKmode)
+		  create_normal_object = true;
+		else
+		  {
+		    /* ...unless we really need to do it.  RM 3.3 says that
+		       the result of evaluating a function call is a constant
+		       object.  As a consequence, it can be the inner object
+		       of a constant renaming.  In this case, the renaming
+		       must be fully instantiated, i.e. it cannot be a mere
+		       reference to (part of) an existing object.  */
+		    tree inner_object = gnu_expr;
+		    while (handled_component_p (inner_object))
+		      inner_object = TREE_OPERAND (inner_object, 0);
+		    if (TREE_CODE (inner_object) == CALL_EXPR)
+		      create_normal_object = true;
+		  }
+	      }
 
 	    /* Otherwise, see if we can proceed with a stabilized version of
 	       the renamed entity or if we need to make a pointer.  */
-	    else
+	    if (!create_normal_object)
 	      {
-		bool stabilized = false;
+		bool stable = false;
 		tree maybe_stable_expr = NULL_TREE;
 
 		/* Case 2: If the renaming entity need not be materialized and
@@ -794,12 +816,15 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 			    && !TREE_SIDE_EFFECTS (gnu_expr))))
 		  {
 		    maybe_stable_expr
-		      = maybe_stabilize_reference (gnu_expr, true, false,
-						   &stabilized);
+		      = maybe_stabilize_reference (gnu_expr, true, &stable);
 
-		    if (stabilized)
+		    if (stable)
 		      {
 			gnu_decl = maybe_stable_expr;
+			/* ??? No DECL_EXPR is created so we need to mark
+			   the expression manually lest it is shared.  */
+			if (global_bindings_p ())
+			  TREE_VISITED (gnu_decl) = 1;
 			save_gnu_tree (gnat_entity, gnu_decl, true);
 			saved = true;
 			break;
@@ -812,16 +837,14 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 
 		/* Case 3: Make this into a constant pointer to the object we
 		   are to rename and attach the object to the pointer if it is
-		   an lvalue that can be stabilized.
+		   something we can stabilize.
 
 		   From the proper scope, attached objects will be referenced
 		   directly instead of indirectly via the pointer to avoid
-		   subtle aliasing problems with non addressable entities.
+		   subtle aliasing problems with non-addressable entities.
 		   They have to be stable because we must not evaluate the
 		   variables in the expression every time the renaming is used.
-		   They also have to be lvalues because the context in which
-		   they are reused sometimes requires so.  We call pointers
-		   with an attached object "renaming" pointers.
+		   The pointer is called a "renaming" pointer in this case.
 
 		   In the rare cases where we cannot stabilize the renamed
 		   object, we just make a "bare" pointer, and the renamed
@@ -831,18 +854,17 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 		  const_flag = true;
 		  gnu_type = build_reference_type (gnu_type);
 
-		  /* If a previous attempt at unrestricted stabilization
-		     failed, there is no point trying again and we can reuse
-		     the result without attaching it to the pointer.  In this
-		     case it will only be used as the initializing expression
-		     of the pointer and thus needs no special treatment with
-		     regard to multiple evaluations.  */
+		  /* If the previous attempt at stabilization failed, there is
+		     no point in trying again and we reuse the result without
+		     attaching it to the pointer.  In this case it will only
+		     be used as the initializing expression of the pointer
+		     and thus needs no special treatment with regard to
+		     multiple evaluations.  */
 		  if (maybe_stable_expr)
 		    ;
 
-		  /* Otherwise, try to stabilize now, restricting to lvalues
-		     only, and attach the expression to the pointer if the
-		     stabilization succeeds.
+		  /* Otherwise, try to stabilize now and attach the expression
+		     to the pointer if the stabilization succeeds.
 
 		     Note that this might introduce SAVE_EXPRs and we don't
 		     check whether we're at the global level or not.  This is
@@ -852,18 +874,16 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 		     place in a correct program.
 
 		     SAVE_EXPRs will be evaluated at the right spots by either
-		     create_var_decl->expand_decl_init for the non-global case
-		     or build_unit_elab for the global case, and will be
-		     attached to the elaboration procedure by the RTL expander
-		     in the latter case.  We have no need to force an early
-		     evaluation here.  */
+		     the evaluation of the initializer for the non-global case
+		     or the elaboration code for the global case, and will be
+		     attached to the elaboration procedure in the latter case.
+		     We have no need to force an early evaluation here.  */
 		  else
 		    {
 		      maybe_stable_expr
-			= maybe_stabilize_reference (gnu_expr, true, true,
-						     &stabilized);
+			= maybe_stabilize_reference (gnu_expr, true, &stable);
 
-		      if (stabilized)
+		      if (stable)
 			renamed_obj = maybe_stable_expr;
 
 		      /* Attaching is actually performed downstream, as soon
@@ -1056,24 +1076,24 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	      }
 	  }
 
-	/* If this object would go into the stack and has an alignment
-	   larger than the default largest alignment, make a variable
-	   to hold the "aligning type" with a modified initial value,
-	   if any, then point to it and make that the value of this
-	   variable, which is now indirect.  */
+	/* If this object would go into the stack and has an alignment larger
+	   than the largest stack alignment the back-end can honor, resort to
+	   a variable of "aligning type".  */
 	if (!global_bindings_p () && !static_p && definition
 	    && !imported_p && TYPE_ALIGN (gnu_type) > BIGGEST_ALIGNMENT)
 	  {
+	    /* Create the new variable.  No need for extra room before the
+	       aligned field as this is in automatic storage.  */
 	    tree gnu_new_type
 	      = make_aligning_type (gnu_type, TYPE_ALIGN (gnu_type),
-				    TYPE_SIZE_UNIT (gnu_type));
-	    tree gnu_new_var;
-
-	    gnu_new_var
+				    TYPE_SIZE_UNIT (gnu_type),
+				    BIGGEST_ALIGNMENT, 0);
+	    tree gnu_new_var
 	      = create_var_decl (create_concat_name (gnat_entity, "ALIGN"),
 				 NULL_TREE, gnu_new_type, NULL_TREE, false,
 				 false, false, false, NULL, gnat_entity);
 
+	    /* Initialize the aligned field if we have an initializer.  */
 	    if (gnu_expr)
 	      add_stmt_with_node
 		(build_binary_op (MODIFY_EXPR, NULL_TREE,
@@ -1083,6 +1103,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 				  gnu_expr),
 		 gnat_entity);
 
+	    /* And setup this entity as a reference to the aligned field.  */
 	    gnu_type = build_reference_type (gnu_type);
 	    gnu_expr
 	      = build_unary_op
@@ -1457,6 +1478,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	  gnu_type = make_node (RECORD_TYPE);
 	  TYPE_NAME (gnu_type) = create_concat_name (gnat_entity, "JM");
 	  TYPE_ALIGN (gnu_type) = TYPE_ALIGN (gnu_field_type);
+	  TYPE_USER_ALIGN (gnu_type) = TYPE_USER_ALIGN (gnu_field_type);
 	  TYPE_PACKED (gnu_type) = 1;
 
 	  /* Create a stripped-down declaration of the original type, mainly
@@ -1470,7 +1492,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	  gnu_field = create_field_decl (get_identifier ("OBJECT"),
 					 gnu_field_type, gnu_type, 1, 0, 0, 0);
 
-	  finish_record_type (gnu_type, gnu_field, false, false);
+	  finish_record_type (gnu_type, gnu_field, 0, false);
 	  TYPE_JUSTIFIED_MODULAR_P (gnu_type) = 1;
 	  SET_TYPE_ADA_SIZE (gnu_type, bitsize_int (esize));
 
@@ -1587,9 +1609,6 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 
 	TYPE_NAME (gnu_template_type)
 	  = create_concat_name (gnat_entity, "XUB");
-	TYPE_NAME (gnu_fat_type) = create_concat_name (gnat_entity, "XUP");
-	TYPE_IS_FAT_POINTER_P (gnu_fat_type) = 1;
-	TYPE_READONLY (gnu_template_type) = 1;
 
 	/* Make a node for the array.  If we are not defining the array
 	   suppress expanding incomplete types.  */
@@ -1611,7 +1630,11 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 
 	/* Make sure we can put this into a register.  */
 	TYPE_ALIGN (gnu_fat_type) = MIN (BIGGEST_ALIGNMENT, 2 * POINTER_SIZE);
-	finish_record_type (gnu_fat_type, tem, false, true);
+
+	/* Do not finalize this record type since the types of its fields
+	   are still incomplete at this point.  */
+	finish_record_type (gnu_fat_type, tem, 0, true);
+	TYPE_IS_FAT_POINTER_P (gnu_fat_type) = 1;
 
 	/* Build a reference to the template from a PLACEHOLDER_EXPR that
 	   is the fat pointer.  This will be used to access the individual
@@ -1678,7 +1701,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	      = create_index_type (convert (sizetype, gnu_min),
 				   convert (sizetype, gnu_max),
 				   build_range_type (gnu_ind_subtype,
-						     gnu_min, gnu_max));
+						     gnu_min, gnu_max),
+				   gnat_entity);
 	    /* Update the maximum size of the array, in elements. */
 	    gnu_max_size
 	      = size_binop (MULT_EXPR, gnu_max_size,
@@ -1695,13 +1719,11 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	    = chainon (gnu_template_fields, gnu_temp_fields[index]);
 
 	/* Install all the fields into the template.  */
-	finish_record_type (gnu_template_type, gnu_template_fields,
-			    false, false);
+	finish_record_type (gnu_template_type, gnu_template_fields, 0, false);
 	TYPE_READONLY (gnu_template_type) = 1;
 
 	/* Now make the array of arrays and update the pointer to the array
 	   in the fat pointer.  Note that it is the first field.  */
-
 	tem = gnat_to_gnu_type (Component_Type (gnat_entity));
 
 	/* Get and validate any specified Component_Size, but if Packed,
@@ -1724,9 +1746,17 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 
 	if (!Is_Bit_Packed_Array (gnat_entity) && gnu_comp_size)
 	  {
+	    tree orig_tem;
 	    tem = make_type_from_size (tem, gnu_comp_size, false);
+	    orig_tem = tem;
 	    tem = maybe_pad_type (tem, gnu_comp_size, 0, gnat_entity,
 				  "C_PAD", false, definition, true);
+	    /* If a padding record was made, declare it now since it will
+	       never be declared otherwise.  This is necessary in order to
+	       ensure that its subtrees are properly marked.  */
+	    if (tem != orig_tem)
+	      create_type_decl (TYPE_NAME (tem), tem, NULL, true, false,
+				gnat_entity);
 	  }
 
 	if (Has_Volatile_Components (gnat_entity))
@@ -1802,16 +1832,18 @@ 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);
 
-	/* Create a record type for the object and its template and
-	   set the template at a negative offset.  */
+	/* Give the fat pointer type a name.  */
+	create_type_decl (create_concat_name (gnat_entity, "XUP"),
+			  gnu_fat_type, NULL, !Comes_From_Source (gnat_entity),
+			  debug_info_p, gnat_entity);
+
+       /* Create the type to be used as what a thin pointer designates: an
+          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"));
-	DECL_FIELD_OFFSET (TYPE_FIELDS (tem))
-	  = size_binop (MINUS_EXPR, size_zero_node,
-			byte_position (TREE_CHAIN (TYPE_FIELDS (tem))));
-	DECL_FIELD_OFFSET (TREE_CHAIN (TYPE_FIELDS (tem))) = size_zero_node;
-	DECL_FIELD_BIT_OFFSET (TREE_CHAIN (TYPE_FIELDS (tem)))
-	  = bitsize_zero_node;
+	shift_unc_components_for_thin_pointers (tem);
+
 	SET_TYPE_UNCONSTRAINED_ARRAY (tem, gnu_type);
 	TYPE_OBJECT_RECORD_TYPE (gnu_type) = tem;
 
@@ -1962,7 +1994,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 		     gnu_max, gnu_high);
 
 	      gnu_index_type[index]
-		= create_index_type (gnu_min, gnu_high, gnu_index_subtype);
+		= create_index_type (gnu_min, gnu_high, gnu_index_subtype,
+				     gnat_entity);
 
 	      /* Also compute the maximum size of the array.  Here we
 		 see if any constraint on the index type of the base type
@@ -2054,10 +2087,18 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 
 	  if (!Is_Bit_Packed_Array (gnat_entity) && gnu_comp_size)
 	    {
+	      tree orig_gnu_type;
 	      gnu_type = make_type_from_size (gnu_type, gnu_comp_size, false);
+	      orig_gnu_type = gnu_type;
 	      gnu_type = maybe_pad_type (gnu_type, gnu_comp_size, 0,
 					 gnat_entity, "C_PAD", false,
 					 definition, true);
+	      /* If a padding record was made, declare it now since it will
+		 never be declared otherwise.  This is necessary in order to
+		 ensure that its subtrees are properly marked.  */
+	      if (gnu_type != orig_gnu_type)
+		create_type_decl (TYPE_NAME (gnu_type), gnu_type, NULL, true,
+				  false, gnat_entity);
 	    }
 
 	  if (Has_Volatile_Components (Base_Type (gnat_entity)))
@@ -2123,6 +2164,10 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 			concat_id_with_name (gnu_str_name, "A_U"),
 			definition, 0),
 		       size_int (TYPE_ALIGN (eltype) / BITS_PER_UNIT));
+
+		  /* ??? create_type_decl is not invoked on the inner types so
+		     the MULT_EXPR node built above will never be marked.  */
+		  TREE_VISITED (TYPE_SIZE_UNIT (gnu_arr_type)) = 1;
 		}
 	    }
 
@@ -2154,7 +2199,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 		}
 
 	      finish_record_type (gnu_bound_rec_type, gnu_field_list,
-				  false, false);
+				  0, false);
 	    }
 
 	  TYPE_CONVENTION_FORTRAN_P (gnu_type)
@@ -2211,9 +2256,10 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	  gnu_decl = gnat_to_gnu_entity (Packed_Array_Type (gnat_entity),
 					 NULL_TREE, 0);
 	  this_made_decl = true;
-	  gnu_inner_type = gnu_type = TREE_TYPE (gnu_decl);
+	  gnu_type = TREE_TYPE (gnu_decl);
 	  save_gnu_tree (gnat_entity, NULL_TREE, false);
 
+	  gnu_inner_type = gnu_type;
 	  while (TREE_CODE (gnu_inner_type) == RECORD_TYPE
 		 && (TYPE_JUSTIFIED_MODULAR_P (gnu_inner_type)
 		     || TYPE_IS_PADDING_P (gnu_inner_type)))
@@ -2312,7 +2358,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 					TYPE_MIN_VALUE (gnu_range_type)),
 			       convert (sizetype,
 					TYPE_MAX_VALUE (gnu_range_type)),
-			       gnu_range_type);
+			       gnu_range_type, gnat_entity);
 
 	gnu_type
 	  = build_array_type (gnat_to_gnu_type (Component_Type (gnat_entity)),
@@ -2368,10 +2414,14 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	tree gnu_field;
 	tree gnu_field_list = NULL_TREE;
 	tree gnu_get_parent;
-	int packed = (Is_Packed (gnat_entity) ? 1
-		      : (Component_Alignment (gnat_entity)
-			 == Calign_Storage_Unit) ? -1
-		      : 0);
+	int packed
+	  = Is_Packed (gnat_entity)
+	    ? 1
+	    : Component_Alignment (gnat_entity) == Calign_Storage_Unit
+	      ? -1
+	      : Known_Alignment (gnat_entity)
+		? -2
+		: 0;
 	bool has_rep = Has_Specified_Layout (gnat_entity);
 	bool all_rep = has_rep;
 	bool is_extension
@@ -2404,16 +2454,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	   suppress expanding incomplete types.  */
 	gnu_type = make_node (tree_code_for_record_type (gnat_entity));
 	TYPE_NAME (gnu_type) = gnu_entity_id;
-	/* ??? We should have create_type_decl like in the E_Record_Subtype
-	   case below.  Unfortunately this would cause GNU_TYPE to be marked
-	   as visited, thus precluding the subtrees of the type that will be
-	   built below from being marked as visited when the real TYPE_DECL
-	   is eventually created.  A solution could be to devise a special
-	   version of the function under the name create_type_stub_decl.  */
-	TYPE_STUB_DECL (gnu_type)
-	  = build_decl (TYPE_DECL, NULL_TREE, gnu_type);
-	TYPE_ALIGN (gnu_type) = 0;
-	TYPE_PACKED (gnu_type) = packed || has_rep;
+	TYPE_PACKED (gnu_type) = (packed != 0) || has_rep;
 
 	if (!definition)
 	  defer_incomplete_level++, this_deferred = true;
@@ -2435,6 +2476,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	  TYPE_ALIGN (gnu_type)
 	    = (esize >= BITS_PER_WORD ? BITS_PER_WORD
 	       : 1 << (floor_log2 (esize - 1) + 1));
+	else
+	  TYPE_ALIGN (gnu_type) = 0;
 
 	/* If we have a Parent_Subtype, make a field for the parent.  If
 	   this record has rep clauses, force the position to zero.  */
@@ -2455,7 +2498,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	    gnu_get_parent = build3 (COMPONENT_REF, void_type_node,
 				     build0 (PLACEHOLDER_EXPR, gnu_type),
 				     build_decl (FIELD_DECL, NULL_TREE,
-						 NULL_TREE),
+						 void_type_node),
 				     NULL_TREE);
 
 	    if (Has_Discriminants (gnat_entity))
@@ -2552,26 +2595,15 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	   variants.  */
 	TYPE_FIELDS (gnu_type) = gnu_field_list;
 
-	/* Add the listed fields into the record and finish up.  */
+	/* Add the listed fields into the record and finish it up.  */
 	components_to_record (gnu_type, Component_List (record_definition),
 			      gnu_field_list, packed, definition, NULL,
-			      false, all_rep, this_deferred,
+			      false, all_rep, false,
 			      Is_Unchecked_Union (gnat_entity));
 
-        if (this_deferred)
-	  {
-	    debug_deferred = true;
-	    defer_debug_level++;
-
-	    defer_debug_incomplete_list
-	      = tree_cons (NULL_TREE, gnu_type,
-			   defer_debug_incomplete_list);
-	  }
-
 	/* We used to remove the associations of the discriminants and
 	   _Parent for validity checking, but we may need them if there's
 	   Freeze_Node for a subtype used in this record.  */
-
 	TYPE_VOLATILE (gnu_type) = Treat_As_Volatile (gnat_entity);
 	TYPE_BY_REFERENCE_P (gnu_type) = Is_By_Reference_Type (gnat_entity);
 
@@ -2609,10 +2641,9 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
       /* If an equivalent type is present, that is what we should use.
 	 Otherwise, fall through to handle this like a record subtype
 	 since it may have constraints.  */
-      if (Present (Equivalent_Type (gnat_entity)))
+      if (gnat_equiv_type != gnat_entity)
 	{
-	  gnu_decl = gnat_to_gnu_entity (Equivalent_Type (gnat_entity),
-					 NULL_TREE, 0);
+	  gnu_decl = gnat_to_gnu_entity (gnat_equiv_type, NULL_TREE, 0);
 	  maybe_present = true;
 	  break;
 	}
@@ -2651,12 +2682,13 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	  /* Get the base type initially for its alignment and sizes.  But
 	     if it is a padded type, we do all the other work with the
 	     unpadded type.  */
-	  gnu_type = gnu_orig_type = gnu_base_type
-	    = gnat_to_gnu_type (gnat_base_type);
+	  gnu_base_type = gnat_to_gnu_type (gnat_base_type);
 
-	  if (TREE_CODE (gnu_type) == RECORD_TYPE
-	      && TYPE_IS_PADDING_P (gnu_type))
-	    gnu_type = gnu_orig_type = TREE_TYPE (TYPE_FIELDS (gnu_type));
+	  if (TREE_CODE (gnu_base_type) == RECORD_TYPE
+	      && TYPE_IS_PADDING_P (gnu_base_type))
+	    gnu_type = gnu_orig_type = TREE_TYPE (TYPE_FIELDS (gnu_base_type));
+	  else
+	    gnu_type = gnu_orig_type = gnu_base_type;
 
 	  if (present_gnu_tree (gnat_entity))
 	    {
@@ -2694,10 +2726,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 
 	      gnu_type = make_node (RECORD_TYPE);
 	      TYPE_NAME (gnu_type) = gnu_entity_id;
-	      TYPE_STUB_DECL (gnu_type)
-		= create_type_decl (NULL_TREE, gnu_type, NULL, false, false,
-				    gnat_entity);
 	      TYPE_ALIGN (gnu_type) = TYPE_ALIGN (gnu_base_type);
+	      TYPE_VOLATILE (gnu_type) = Treat_As_Volatile (gnat_entity);
 
 	      for (gnat_field = First_Entity (gnat_entity);
 		   Present (gnat_field); gnat_field = Next_Entity (gnat_field))
@@ -2811,8 +2841,9 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 		    && !present_gnu_tree (Etype (gnat_field)))
 		  gnat_to_gnu_entity (Etype (gnat_field), NULL_TREE, 0);
 
+	      /* Do not finalize it since we're going to modify it below.  */
 	      finish_record_type (gnu_type, nreverse (gnu_field_list),
-				  true, false);
+				  2, true);
 
 	      /* Now set the size, alignment and alias set of the new type to
 		 match that of the old one, doing any substitutions, as
@@ -2847,24 +2878,21 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 						   TREE_PURPOSE (gnu_temp),
 						   TREE_VALUE (gnu_temp)));
 
-	      /* Recompute the mode of this record type now that we know its
-		 actual size.  */
-	      compute_record_mode (gnu_type);
-
 	      /* Reapply variable_size since we have changed the sizes.  */
 	      TYPE_SIZE (gnu_type) = variable_size (TYPE_SIZE (gnu_type));
 	      TYPE_SIZE_UNIT (gnu_type)
 		= variable_size (TYPE_SIZE_UNIT (gnu_type));
 
+	      /* Recompute the mode of this record type now that we know its
+		 actual size.  */
+	      compute_record_mode (gnu_type);
+
 	      /* Fill in locations of fields.  */
 	      annotate_rep (gnat_entity, gnu_type);
-	    }
 
-	  /* If we've made a new type, record it and make an XVS type to show
-	     what this is a subtype of.  Some debuggers require the  XVS
-	     type to be output first, so do it in that order.  */
-	  if (gnu_type != gnu_orig_type)
-	    {
+	      /* We've built a new type, make an XVS type to show what this
+		 is a subtype of.  Some debuggers require the XVS type to be
+		 output first, so do it in that order.  */
 	      if (debug_info_p)
 		{
 		  tree gnu_subtype_marker = make_node (RECORD_TYPE);
@@ -2881,14 +2909,11 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 							 gnu_subtype_marker,
 							 0, NULL_TREE,
 							 NULL_TREE, 0),
-				      false, false);
+				      0, false);
 		}
 
-	      TYPE_VOLATILE (gnu_type) = Treat_As_Volatile (gnat_entity);
-	      TYPE_NAME (gnu_type) = gnu_entity_id;
-	      TYPE_STUB_DECL (gnu_type)
-		= create_type_decl (TYPE_NAME (gnu_type), gnu_type,
-				    NULL, true, debug_info_p, gnat_entity);
+	      /* Now we can finalize it.  */
+	      rest_of_record_type_compilation (gnu_type);
 	    }
 
 	  /* Otherwise, go down all the components in the new type and
@@ -2921,8 +2946,10 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	  gnu_decl = create_type_decl (gnu_entity_id, gnu_type, attr_list,
 				       !Comes_From_Source (gnat_entity),
 				       debug_info_p, gnat_entity);
+	  this_made_decl = true;
+	  gnu_type = TREE_TYPE (gnu_decl);
 	  save_gnu_tree (gnat_entity, gnu_decl, false);
-	  this_made_decl = saved = true;
+	  saved = true;
 
 	  p->old_type = TREE_TYPE (gnu_type);
 	  p->full_type = Directly_Designated_Type (gnat_entity);
@@ -2940,24 +2967,47 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
     case E_General_Access_Type:
       {
 	Entity_Id gnat_desig_type = Directly_Designated_Type (gnat_entity);
+	Entity_Id gnat_desig_equiv = Gigi_Equivalent_Type (gnat_desig_type);
+	bool is_from_limited_with
+	  = (IN (Ekind (gnat_desig_equiv), Incomplete_Kind)
+	     && From_With_Type (gnat_desig_equiv));
+
 	/* Get the "full view" of this entity.  If this is an incomplete
-	   entity from a limited with, treat its non-limited view as the
-	   full view.  Otherwise, if this is an incomplete or private
-	   type, use the full view.  */
+	   entity from a limited with, treat its non-limited view as the full
+	   view.  Otherwise, if this is an incomplete or private type, use the
+	   full view.  In the former case, we might point to a private type,
+	   in which case, we need its full view.  Also, we want to look at the
+	   actual type used for the representation, so this takes a total of
+	   three steps.  */
+	Entity_Id gnat_desig_full_direct_first
+	  = (is_from_limited_with ? Non_Limited_View (gnat_desig_equiv)
+	     : (IN (Ekind (gnat_desig_equiv), Incomplete_Or_Private_Kind)
+		? Full_View (gnat_desig_equiv) : Empty));
+	Entity_Id gnat_desig_full_direct
+	  = ((Present (gnat_desig_full_direct_first)
+	      && IN (Ekind (gnat_desig_full_direct_first), Private_Kind))
+	     ? Full_View (gnat_desig_full_direct_first)
+	     : gnat_desig_full_direct_first);
 	Entity_Id gnat_desig_full
-	  = (IN (Ekind (gnat_desig_type), Incomplete_Kind)
-	     && From_With_Type (gnat_desig_type))
-	    ? Non_Limited_View (gnat_desig_type)
-	    : IN (Ekind (gnat_desig_type), Incomplete_Or_Private_Kind)
-	      ? Full_View (gnat_desig_type)
-	      : Empty;
+	  = Gigi_Equivalent_Type (gnat_desig_full_direct);
+
+	/* This the type actually used to represent the designated type,
+	   either gnat_desig_full or gnat_desig_equiv.  */
+	Entity_Id gnat_desig_rep;
+
+	/* Nonzero if this is a pointer to an unconstrained array.  */
+	bool is_unconstrained_array;
+
 	/* We want to know if we'll be seeing the freeze node for any
 	   incomplete type we may be pointing to.  */
 	bool in_main_unit
 	  = (Present (gnat_desig_full)
 	     ? In_Extended_Main_Code_Unit (gnat_desig_full)
 	     : In_Extended_Main_Code_Unit (gnat_desig_type));
+
+	/* Nonzero if we make a dummy type here.  */
 	bool got_fat_p = false;
+	/* Nonzero if the dummy is a fat pointer. */
 	bool made_dummy = false;
 	tree gnu_desig_type = NULL_TREE;
 	enum machine_mode p_mode = mode_for_size (esize, MODE_INT, 0);
@@ -2965,44 +3015,30 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	if (!targetm.valid_pointer_mode (p_mode))
 	  p_mode = ptr_mode;
 
-	if (No (gnat_desig_full)
-	    && (Ekind (gnat_desig_type) == E_Class_Wide_Type
-		|| (Ekind (gnat_desig_type) == E_Class_Wide_Subtype
-		    && Present (Equivalent_Type (gnat_desig_type)))))
-	  {
-	    if (Present (Equivalent_Type (gnat_desig_type)))
-	      {
-		gnat_desig_full = Equivalent_Type (gnat_desig_type);
-		if (IN (Ekind (gnat_desig_full), Incomplete_Or_Private_Kind))
-		  gnat_desig_full = Full_View (gnat_desig_full);
-	      }
-	    else if (IN (Ekind (Root_Type (gnat_desig_type)),
-			 Incomplete_Or_Private_Kind))
-	      gnat_desig_full = Full_View (Root_Type (gnat_desig_type));
-	  }
-
-	if (Present (gnat_desig_full) && Is_Concurrent_Type (gnat_desig_full))
-	  gnat_desig_full = Corresponding_Record_Type (gnat_desig_full);
-
-	/* If either the designated type or its full view is an
-	   unconstrained array subtype, replace it with the type it's a
-	   subtype of.  This avoids problems with multiple copies of
-	   unconstrained array types.  */
-	if (Ekind (gnat_desig_type) == E_Array_Subtype
-	    && !Is_Constrained (gnat_desig_type))
-	  gnat_desig_type = Etype (gnat_desig_type);
+	/* If either the designated type or its full view is an unconstrained
+	   array subtype, replace it with the type it's a subtype of.  This
+	   avoids problems with multiple copies of unconstrained array types.
+	   Likewise, if the designated type is a subtype of an incomplete
+	   record type, use the parent type to avoid order of elaboration
+	   issues.  This can lose some code efficiency, but there is no
+	   alternative.  */
+	if (Ekind (gnat_desig_equiv) == E_Array_Subtype
+	    && ! Is_Constrained (gnat_desig_equiv))
+	  gnat_desig_equiv = Etype (gnat_desig_equiv);
 	if (Present (gnat_desig_full)
-	    && Ekind (gnat_desig_full) == E_Array_Subtype
-	    && !Is_Constrained (gnat_desig_full))
+	    && ((Ekind (gnat_desig_full) == E_Array_Subtype
+		 && ! Is_Constrained (gnat_desig_full))
+		|| (Ekind (gnat_desig_full) == E_Record_Subtype
+		    && Ekind (Etype (gnat_desig_full)) == E_Record_Type)))
 	  gnat_desig_full = Etype (gnat_desig_full);
 
-        /* If the designated type is a subtype of an incomplete record type,
-           use the parent type to avoid order of elaboration issues.  This
-	   can lose some code efficiency, but there is no alternative.  */
-        if (Present (gnat_desig_full)
-             && Ekind (gnat_desig_full) == E_Record_Subtype
-             && Ekind (Etype (gnat_desig_full)) == E_Record_Type)
-	  gnat_desig_full = Etype (gnat_desig_full);
+	/* Now set the type that actually marks the representation of
+	   the designated type and also flag whether we have a unconstrained
+	   array.  */
+	gnat_desig_rep = gnat_desig_full ? gnat_desig_full : gnat_desig_equiv;
+	is_unconstrained_array
+	  = (Is_Array_Type (gnat_desig_rep)
+	     && ! Is_Constrained (gnat_desig_rep));
 
 	/* If we are pointing to an incomplete type whose completion is an
 	   unconstrained array, make a fat pointer type instead of a pointer
@@ -3012,35 +3048,21 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	   a dummy TYPE_OBJECT_RECORD_TYPE in case we have any thin
 	   pointers to it.  */
 
-	if ((Present (gnat_desig_full)
-	     && Is_Array_Type (gnat_desig_full)
-	     && !Is_Constrained (gnat_desig_full))
-	    || (present_gnu_tree (gnat_desig_type)
-		&& TYPE_IS_DUMMY_P (TREE_TYPE
-				     (get_gnu_tree (gnat_desig_type)))
-		&& Is_Array_Type (gnat_desig_type)
-		&& !Is_Constrained (gnat_desig_type))
-	    || (present_gnu_tree (gnat_desig_type)
-		&& (TREE_CODE (TREE_TYPE (get_gnu_tree (gnat_desig_type)))
-		    == UNCONSTRAINED_ARRAY_TYPE)
-		&& !(TYPE_POINTER_TO (TREE_TYPE
-				     (get_gnu_tree (gnat_desig_type)))))
-	    || (No (gnat_desig_full) && !in_main_unit
-		&& defer_incomplete_level
-		&& !present_gnu_tree (gnat_desig_type)
-		&& Is_Array_Type (gnat_desig_type)
-		&& ! Is_Constrained (gnat_desig_type))
-	    || (in_main_unit && From_With_Type (gnat_entity)
+	if (is_unconstrained_array
 	    && (Present (gnat_desig_full)
-		    ? Present (Freeze_Node (gnat_desig_full))
-		    : Present (Freeze_Node (gnat_desig_type)))
-		&& Is_Array_Type (gnat_desig_type)
-		&& !Is_Constrained (gnat_desig_type)))
+		|| (present_gnu_tree (gnat_desig_equiv)
+		    && TYPE_IS_DUMMY_P (TREE_TYPE
+					(get_gnu_tree (gnat_desig_equiv))))
+		|| (No (gnat_desig_full) && ! in_main_unit
+		    && defer_incomplete_level != 0
+		    && ! present_gnu_tree (gnat_desig_equiv))
+		|| (in_main_unit && is_from_limited_with
+		    && Present (Freeze_Node (gnat_desig_rep)))))
   	  {
 	    tree gnu_old
-	      = (present_gnu_tree (gnat_desig_type)
-		 ? gnat_to_gnu_type (gnat_desig_type)
-		 : make_dummy_type (gnat_desig_type));
+	      = (present_gnu_tree (gnat_desig_rep)
+		 ? TREE_TYPE (get_gnu_tree (gnat_desig_rep))
+		 : make_dummy_type (gnat_desig_rep));
 	    tree fields;
 
 	    /* Show the dummy we get will be a fat pointer.  */
@@ -3072,11 +3094,14 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 		TYPE_ALIGN (gnu_type)
 		  = MIN (BIGGEST_ALIGNMENT, 2 * POINTER_SIZE);
 		TYPE_IS_FAT_POINTER_P (gnu_type) = 1;
-		finish_record_type (gnu_type, fields, false, true);
+
+		/* Do not finalize this record type since the types of
+		   its fields are incomplete.  */
+		finish_record_type (gnu_type, fields, 0, true);
 
 		TYPE_OBJECT_RECORD_TYPE (gnu_old) = make_node (RECORD_TYPE);
 		TYPE_NAME (TYPE_OBJECT_RECORD_TYPE (gnu_old))
-		  = concat_id_with_name (get_entity_name (gnat_desig_type),
+		  = concat_id_with_name (get_entity_name (gnat_desig_equiv),
 					 "XUT");
 		TYPE_DUMMY_P (TYPE_OBJECT_RECORD_TYPE (gnu_old)) = 1;
 	      }
@@ -3091,51 +3116,39 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	   to it.  If it is a reference to an incomplete or private type with a
 	   full view that is a record, make a dummy type node and get the
 	   actual type later when we have verified it is safe.  */
-	else if (!in_main_unit
-		 && !present_gnu_tree (gnat_desig_type)
+	else if ((! in_main_unit
+		  && ! present_gnu_tree (gnat_desig_equiv)
 		  && Present (gnat_desig_full)
-		 && !present_gnu_tree (gnat_desig_full)
+		  && ! present_gnu_tree (gnat_desig_full)
 		  && Is_Record_Type (gnat_desig_full))
-	  {
-	    gnu_desig_type = make_dummy_type (gnat_desig_type);
-	    made_dummy = true;
-	  }
-
-	/* Likewise if we are pointing to a record or array and we are to defer
-	   elaborating incomplete types.  We do this since this access type
-	   may be the full view of some private type.  Note that the
-	   unconstrained array case is handled above. */
-	else if ((!in_main_unit || imported_p) && defer_incomplete_level != 0
-		 && !present_gnu_tree (gnat_desig_type)
-		 && ((Is_Record_Type (gnat_desig_type)
-		      || Is_Array_Type (gnat_desig_type))
-		     || (Present (gnat_desig_full)
-			 && (Is_Record_Type (gnat_desig_full)
-			     || Is_Array_Type (gnat_desig_full)))))
-	  {
-	    gnu_desig_type = make_dummy_type (gnat_desig_type);
-	    made_dummy = true;
-	  }
-
+		 /* Likewise if we are pointing to a record or array and we
+		    are to defer elaborating incomplete types.  We do this
+		    since this access type may be the full view of some
+		    private type.  Note that the unconstrained array case is
+		    handled above. */
+		 || ((! in_main_unit || imported_p)
+		     && defer_incomplete_level != 0
+		     && ! present_gnu_tree (gnat_desig_equiv)
+		     && ((Is_Record_Type (gnat_desig_rep)
+			  || Is_Array_Type (gnat_desig_rep))))
 		 /* If this is a reference from a limited_with type back to our
 		    main unit and there's a Freeze_Node for it, either we have
 		    already processed the declaration and made the dummy type,
 		    in which case we just reuse the latter, or we have not yet,
 		    in which case we make the dummy type and it will be reused
-	   when the declaration is processed.  In both cases, the pointer
-	   eventually created below will be automatically adjusted when
-	   the Freeze_Node is processed.  Note that the unconstrained
-	   array case is handled above. */
-	else if (in_main_unit && From_With_Type (gnat_entity)
-		 && (Present (gnat_desig_full)
-		     ? Present (Freeze_Node (gnat_desig_full))
-		     : Present (Freeze_Node (gnat_desig_type))))
+		    when the declaration is processed.  In both cases, the
+		    pointer eventually created below will be automatically
+		    adjusted when the Freeze_Node is processed.  Note that the
+		    unconstrained array case is handled above. */
+		 ||  (in_main_unit && is_from_limited_with
+		      && Present (Freeze_Node (gnat_desig_rep))))
 	  {
-	    gnu_desig_type = make_dummy_type (gnat_desig_type);
-	    made_dummy = true;
+	    gnu_desig_type = make_dummy_type (gnat_desig_equiv);
+  	    made_dummy = 1;
   	  }
 
-	else if (gnat_desig_type == gnat_entity)
+	/* Otherwise handle the case of a pointer to itself.  */
+	else if (gnat_desig_equiv == gnat_entity)
 	  {
 	    gnu_type
 	      = build_pointer_type_for_mode (make_node (VOID_TYPE),
@@ -3144,10 +3157,17 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	    TREE_TYPE (gnu_type) = TYPE_POINTER_TO (gnu_type) = gnu_type;
 	  }
 
+	/* If expansion is disabled, the equivalent type of a concurrent
+	   type is absent, so build a dummy pointer type.  */
+	else if (type_annotate_only && No (gnat_desig_equiv))
+	  gnu_type = build_pointer_type (void_type_node);
+
+	/* Finally, handle the straightforward case where we can just
+	   elaborate our designated type and point to it.  */
 	else
-	  gnu_desig_type = gnat_to_gnu_type (gnat_desig_type);
+	  gnu_desig_type = gnat_to_gnu_type (gnat_desig_equiv);
 
-	/* It is possible that the above call to gnat_to_gnu_type resolved our
+	/* It is possible that a call to gnat_to_gnu_type above resolved our
 	   type.  If so, just return it.  */
 	if (present_gnu_tree (gnat_entity))
 	  {
@@ -3202,9 +3222,11 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	   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 (!in_main_unit && made_dummy)
+	   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 is.  */
+	if ((! in_main_unit || is_from_limited_with) && made_dummy)
 	  {
 	    tree gnu_old_type
 	      = TYPE_FAT_POINTER_P (gnu_type)
@@ -3220,10 +3242,18 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	    gnu_decl = create_type_decl (gnu_entity_id, gnu_type, attr_list,
 					 !Comes_From_Source (gnat_entity),
 					 debug_info_p, gnat_entity);
+	    this_made_decl = true;
+	    gnu_type = TREE_TYPE (gnu_decl);
 	    save_gnu_tree (gnat_entity, gnu_decl, false);
-	    this_made_decl = saved = true;
+	    saved = true;
+
+	    if (defer_incomplete_level == 0
+		&& ! (is_from_limited_with
+		      && (in_main_unit
+			  || In_Extended_Main_Code_Unit (gnat_entity))))
+	      update_pointer_to (TYPE_MAIN_VARIANT (gnu_old_type),
+				 gnat_to_gnu_type (gnat_desig_equiv));
 
-	    if (defer_incomplete_level == 0)
 	      /* Note that the call to gnat_to_gnu_type here might have
 		 updated gnu_old_type directly, in which case it is not a
 		 dummy type any more when we get into update_pointer_to.
@@ -3236,17 +3266,21 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 		 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.  */
-	      update_pointer_to (TYPE_MAIN_VARIANT (gnu_old_type),
-				 gnat_to_gnu_type (gnat_desig_type));
 	    else
 	      {
 		struct incomplete *p
-		  = (struct incomplete *) xmalloc (sizeof (struct incomplete));
+		  = (struct incomplete *) xmalloc (sizeof
+						   (struct incomplete));
+		struct incomplete **head
+		  = (is_from_limited_with
+		     && (in_main_unit
+			 || In_Extended_Main_Code_Unit (gnat_entity))
+		     ? &defer_limited_with : &defer_incomplete_list);
 
 		p->old_type = gnu_old_type;
-		p->full_type = gnat_desig_type;
-		p->next = defer_incomplete_list;
-		defer_incomplete_list = p;
+		p->full_type = gnat_desig_equiv;
+		p->next = *head;
+		*head = p;
 	      }
 	  }
       }
@@ -3254,12 +3288,12 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 
     case E_Access_Protected_Subprogram_Type:
     case E_Anonymous_Access_Protected_Subprogram_Type:
-      if (type_annotate_only && No (Equivalent_Type (gnat_entity)))
+      if (type_annotate_only && No (gnat_equiv_type))
 	gnu_type = build_pointer_type (void_type_node);
       else
 	{
 	  /* The runtime representation is the equivalent type. */
-	  gnu_type = gnat_to_gnu_type (Equivalent_Type (gnat_entity));
+	  gnu_type = gnat_to_gnu_type (gnat_equiv_type);
 	  maybe_present = 1;
 	}
 
@@ -3308,11 +3342,9 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	      p->next = defer_incomplete_list;
 	      defer_incomplete_list = p;
 	    }
-          else if (IN (Ekind (Base_Type
+	  else if (!IN (Ekind (Base_Type
 			      (Directly_Designated_Type (gnat_entity))),
 		       Incomplete_Or_Private_Kind))
-	    ;
-	  else
 	    gnat_to_gnu_entity (Directly_Designated_Type (gnat_entity),
 				NULL_TREE, 0);
 	}
@@ -3329,6 +3361,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 		Is_Imported     Indicates that the subprogram has appeared in
 				an INTERFACE or IMPORT pragma. For now we
 				assume that the external language is C.
+		Is_Exported     Likewise but for an EXPORT pragma.
 		Is_Inlined      True if the subprogram is to be inlined.
 
        In addition for function subprograms we have:
@@ -3348,17 +3381,15 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
        equivalent source rewritings that follow:
 
 						struct temp {int a,b};
-       procedure P (A,B: IN OUT ...) is            temp P (int A,B) {
+       procedure P (A,B: IN OUT ...) is		temp P (int A,B)
+       begin					{
 	 ..					  ..
        end P;					  return {A,B};
 						}
-                              procedure call
 
-                                              {
 						temp t;
        P(X,Y);					t = P(X,Y);
 						X = t.a , Y = t.b;
-                                              }
 
        For subprogram types we need to perform mainly the same conversions to
        GCC form that are needed for procedures and function declarations.  The
@@ -3373,14 +3404,16 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	   PARM_DECL nodes are chained through the TREE_CHAIN field, so this
 	   actually is the head of this parameter list.  */
 	tree gnu_param_list = NULL_TREE;
+	/* Likewise for the stub associated with an exported procedure.  */
+	tree gnu_stub_param_list = NULL_TREE;
 	/* The type returned by a function. If the subprogram is a procedure
 	   this type should be void_type_node.  */
 	tree gnu_return_type = void_type_node;
-        /* List of fields in return type of procedure with copy in copy out
+	/* List of fields in return type of procedure with copy-in copy-out
 	   parameters.  */
 	tree gnu_field_list = NULL_TREE;
-	/* Non-null for subprograms containing  parameters passed by copy in
-	   copy out (Ada IN OUT or OUT parameters not passed by reference),
+	/* Non-null for subprograms containing parameters passed by copy-in
+	   copy-out (Ada IN OUT or OUT parameters not passed by reference),
 	   in which case it is the list of nodes used to specify the values of
 	   the in out/out parameters that are returned as a record upon
 	   procedure return.  The TREE_PURPOSE of an element of this list is
@@ -3391,6 +3424,9 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	/* If an import pragma asks to map this subprogram to a GCC builtin,
 	   this is the builtin DECL node.  */
 	tree gnu_builtin_decl = NULL_TREE;
+	/* For the stub associated with an exported procedure.  */
+	tree gnu_stub_type = NULL_TREE, gnu_stub_name = NULL_TREE;
+	tree gnu_ext_name = create_concat_name (gnat_entity, NULL);
 	Entity_Id gnat_param;
 	bool inline_flag = Is_Inlined (gnat_entity);
 	bool public_flag = Is_Public (gnat_entity);
@@ -3401,8 +3437,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	bool returns_by_ref = false;
 	bool returns_unconstrained = false;
 	bool returns_by_target_ptr = false;
-	tree gnu_ext_name = create_concat_name (gnat_entity, 0);
 	bool has_copy_in_out = false;
+	bool has_stub = false;
 	int parmnum;
 
 	if (kind == E_Subprogram_Type && !definition)
@@ -3535,6 +3571,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	   each.  While doing this, build a copy-out structure if
 	   we need one.  */
 
+	/* Loop over the parameters and get their associated GCC tree.
+	   While doing this, build a copy-out structure if we need one.  */
 	for (gnat_param = First_Formal_With_Extras (gnat_entity), parmnum = 0;
 	     Present (gnat_param);
 	     gnat_param = Next_Formal_With_Extras (gnat_param), parmnum++)
@@ -3542,196 +3580,81 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	    tree gnu_param_name = get_entity_name (gnat_param);
 	    tree gnu_param_type = gnat_to_gnu_type (Etype (gnat_param));
 	    tree gnu_param, gnu_field;
-	    bool by_ref_p = false;
-	    bool by_descr_p = false;
-	    bool by_component_ptr_p = false;
-	    bool copy_in_copy_out_flag = false;
-	    bool req_by_copy = false, req_by_ref = false;
+	    bool copy_in_copy_out = false;
+	    Mechanism_Type mech = Mechanism (gnat_param);
 
 	    /* Builtins are expanded inline and there is no real call sequence
-	       involved. so the type expected by the underlying expander is
+	       involved.  So the type expected by the underlying expander is
 	       always the type of each argument "as is".  */
 	    if (gnu_builtin_decl)
-	      req_by_copy = 1;
-
+	      mech = By_Copy;
+	    /* Handle the first parameter of a valued procedure specially.  */
+	    else if (Is_Valued_Procedure (gnat_entity) && parmnum == 0)
+	      mech = By_Copy_Return;
 	    /* Otherwise, see if a Mechanism was supplied that forced this
 	       parameter to be passed one way or another.  */
-	    else if (Is_Valued_Procedure (gnat_entity) && parmnum == 0)
-	      req_by_copy = true;
-	    else if (Mechanism (gnat_param) == Default)
+	    else if (mech == Default
+		     || mech == By_Copy || mech == By_Reference)
 	      ;
-	    else if (Mechanism (gnat_param) == By_Copy)
-	      req_by_copy = true;
-	    else if (Mechanism (gnat_param) == By_Reference)
-	      req_by_ref = true;
-	    else if (Mechanism (gnat_param) <= By_Descriptor)
-	      by_descr_p = true;
-	    else if (Mechanism (gnat_param) > 0)
+	    else if (By_Descriptor_Last <= mech && mech <= By_Descriptor)
+	      mech = By_Descriptor;
+	    else if (mech > 0)
 	      {
 		if (TREE_CODE (gnu_param_type) == UNCONSTRAINED_ARRAY_TYPE
 		    || TREE_CODE (TYPE_SIZE (gnu_param_type)) != INTEGER_CST
 		    || 0 < compare_tree_int (TYPE_SIZE (gnu_param_type),
-					     Mechanism (gnat_param)))
-		  req_by_ref = true;
+					     mech))
+		  mech = By_Reference;
 		else
-		  req_by_copy = true;
+		  mech = By_Copy;
 	      }
 	    else
-	      post_error ("unsupported mechanism for&", gnat_param);
-
-	    /* If this is either a foreign function or if the
-	       underlying type won't be passed by reference, strip off
-	       possible padding type.  */
-	    if (TREE_CODE (gnu_param_type) == RECORD_TYPE
-		&& TYPE_IS_PADDING_P (gnu_param_type)
-		&& (req_by_ref || Has_Foreign_Convention (gnat_entity)
-		    || (!must_pass_by_ref (TREE_TYPE (TYPE_FIELDS
-					              (gnu_param_type)))
-			&& (req_by_copy
-			    || !default_pass_by_ref (TREE_TYPE
-			    			      (TYPE_FIELDS
-						       (gnu_param_type)))))))
-	      gnu_param_type = TREE_TYPE (TYPE_FIELDS (gnu_param_type));
-
-	    /* If this is an IN parameter it is read-only, so make a variant
-	       of the type that is read-only.
-
-	       ??? However, if this is an unconstrained array, that type can
-	       be very complex.  So skip it for now.  Likewise for any other
-	       self-referential type.  */
-	    if (Ekind (gnat_param) == E_In_Parameter
-		&& TREE_CODE (gnu_param_type) != UNCONSTRAINED_ARRAY_TYPE
-		&& !CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_param_type)))
-	      gnu_param_type
-		= build_qualified_type (gnu_param_type,
-					(TYPE_QUALS (gnu_param_type)
-					 | TYPE_QUAL_CONST));
-
-	    /* For foreign conventions, pass arrays as a pointer to the
-	       underlying type.  First check for unconstrained array and get
-	       the underlying array.  Then get the component type and build
-	       a pointer to it.  */
-	    if (Has_Foreign_Convention (gnat_entity)
-		&& TREE_CODE (gnu_param_type) == UNCONSTRAINED_ARRAY_TYPE)
-	      gnu_param_type
-		= TREE_TYPE (TREE_TYPE (TYPE_FIELDS
-					(TREE_TYPE (gnu_param_type))));
-
-	    if (by_descr_p)
-	      gnu_param_type
-		= build_pointer_type
-		  (build_vms_descriptor (gnu_param_type,
-					 Mechanism (gnat_param), gnat_entity));
-
-	    else if (Has_Foreign_Convention (gnat_entity)
-		     && !req_by_copy
-		     && TREE_CODE (gnu_param_type) == ARRAY_TYPE)
 	      {
-		/* Strip off any multi-dimensional entries, then strip
-		   off the last array to get the component type.  */
-		while (TREE_CODE (TREE_TYPE (gnu_param_type)) == ARRAY_TYPE
-		       && TYPE_MULTI_ARRAY_P (TREE_TYPE (gnu_param_type)))
-		  gnu_param_type = TREE_TYPE (gnu_param_type);
-
-		by_component_ptr_p = true;
-		gnu_param_type = TREE_TYPE (gnu_param_type);
-
-		if (Ekind (gnat_param) == E_In_Parameter)
-		  gnu_param_type
-		    = build_qualified_type (gnu_param_type,
-					    (TYPE_QUALS (gnu_param_type)
-					     | TYPE_QUAL_CONST));
-
-		gnu_param_type = build_pointer_type (gnu_param_type);
+		post_error ("unsupported mechanism for&", gnat_param);
+		mech = Default;
 	      }
 
-	    /* Fat pointers are passed as thin pointers for foreign
-	       conventions.  */
-	    else if (Has_Foreign_Convention (gnat_entity)
-		     && TYPE_FAT_POINTER_P (gnu_param_type))
-	      gnu_param_type
-		= make_type_from_size (gnu_param_type,
-				       size_int (POINTER_SIZE), false);
-
-	    /* If we must pass or were requested to pass by reference, do so.
-	       If we were requested to pass by copy, do so.
-	       Otherwise, for foreign conventions, pass all in out parameters
-	       or aggregates by reference.  For COBOL and Fortran, pass
-	       all integer and FP types that way too.  For Convention Ada,
-	       use the standard Ada default.  */
-	    else if (must_pass_by_ref (gnu_param_type) || req_by_ref
-		     || (!req_by_copy
-			 && ((Has_Foreign_Convention (gnat_entity)
-			      && (Ekind (gnat_param) != E_In_Parameter
-				  || AGGREGATE_TYPE_P (gnu_param_type)))
-			     || (((Convention (gnat_entity)
-				   == Convention_Fortran)
-				  || (Convention (gnat_entity)
-				      == Convention_COBOL))
-				 && (INTEGRAL_TYPE_P (gnu_param_type)
-				     || FLOAT_TYPE_P (gnu_param_type)))
-			     /* For convention Ada, see if we pass by reference
-				by default.  */
-			     || (!Has_Foreign_Convention (gnat_entity)
-				 && default_pass_by_ref (gnu_param_type)))))
+	    gnu_param
+	      = gnat_to_gnu_param (gnat_param, mech, gnat_entity,
+				   Has_Foreign_Convention (gnat_entity),
+				   &copy_in_copy_out);
+
+	    /* We are returned either a PARM_DECL or a type if no parameter
+	       needs to be passed; in either case, adjust the type.  */
+	    if (DECL_P (gnu_param))
+	      gnu_param_type = TREE_TYPE (gnu_param);
+	    else
 	      {
-		gnu_param_type = build_reference_type (gnu_param_type);
-		by_ref_p = true;
+		gnu_param_type = gnu_param;
+		gnu_param = NULL_TREE;
 	      }
 
-	    else if (Ekind (gnat_param) != E_In_Parameter)
-	      copy_in_copy_out_flag = true;
-
-	    if (req_by_copy && (by_ref_p || by_component_ptr_p))
-	      post_error ("?cannot pass & by copy", gnat_param);
-
-	    /* If this is an OUT parameter that isn't passed by reference
-	       and isn't a pointer or aggregate, we don't make a PARM_DECL
-	       for it.  Instead, it will be a VAR_DECL created when we process
-	       the procedure.  For the special parameter of Valued_Procedure,
-	       never pass it in.
-
-	       An exception is made to cover the RM-6.4.1 rule requiring "by
-	       copy" out parameters with discriminants or implicit initial
-	       values to be handled like in out parameters. These type are
-	       normally built as aggregates, and hence passed by reference,
-	       except for some packed arrays which end up encoded in special
-	       integer types.
-
-	       The exception we need to make is then for packed arrays of
-	       records with discriminants or implicit initial values. We have
-	       no light/easy way to check for the latter case, so we merely
-	       check for packed arrays of records. This may lead to useless
-	       copy-in operations, but in very rare cases only, as these would
-	       be exceptions in a set of already exceptional situations.  */
-	    if (Ekind (gnat_param) == E_Out_Parameter && !by_ref_p
-		&& ((Is_Valued_Procedure (gnat_entity) && parmnum == 0)
-		    || (!by_descr_p
-			&& !POINTER_TYPE_P (gnu_param_type)
-			&& !AGGREGATE_TYPE_P (gnu_param_type)))
-		&& !(Is_Array_Type (Etype (gnat_param))
-		     && Is_Packed (Etype (gnat_param))
-		     && Is_Composite_Type (Component_Type
-					   (Etype (gnat_param)))))
-	      gnu_param = NULL_TREE;
-	    else
+	    if (gnu_param)
+	      {
+		/* If it's an exported subprogram, we build a parameter list
+		   in parallel, in case we need to emit a stub for it.  */
+		if (Is_Exported (gnat_entity))
+		  {
+		    gnu_stub_param_list
+		      = chainon (gnu_param, gnu_stub_param_list);
+		    /* Change By_Descriptor parameter to By_Reference for
+		       the internal version of an exported subprogram.  */
+		    if (mech == By_Descriptor)
 		      {
 			gnu_param
-		  = create_param_decl
-		    (gnu_param_name, gnu_param_type,
-		     by_ref_p || by_component_ptr_p
-		     || Ekind (gnat_param) == E_In_Parameter);
-
-		DECL_BY_REF_P (gnu_param) = by_ref_p;
-		DECL_BY_COMPONENT_PTR_P (gnu_param) = by_component_ptr_p;
-		DECL_BY_DESCRIPTOR_P (gnu_param) = by_descr_p;
-		DECL_POINTS_TO_READONLY_P (gnu_param)
-		  = (Ekind (gnat_param) == E_In_Parameter
-		     && (by_ref_p || by_component_ptr_p));
+			  = gnat_to_gnu_param (gnat_param, By_Reference,
+					       gnat_entity, false,
+					       &copy_in_copy_out);
+			has_stub = true;
+		      }
+		    else
+		      gnu_param = copy_node (gnu_param);
+		  }
+
+		gnu_param_list = chainon (gnu_param, gnu_param_list);
 		Sloc_to_locus (Sloc (gnat_param),
 			       &DECL_SOURCE_LOCATION (gnu_param));
 		save_gnu_tree (gnat_param, gnu_param, false);
-		gnu_param_list = chainon (gnu_param, gnu_param_list);
 
 		/* If a parameter is a pointer, this function may modify
 		   memory through it and thus shouldn't be considered
@@ -3743,7 +3666,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 		  pure_flag = false;
 	      }
 
-	    if (copy_in_copy_out_flag)
+	    if (copy_in_copy_out)
 	      {
 		if (!has_copy_in_out)
 		  {
@@ -3766,26 +3689,9 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 
 	/* Do not compute record for out parameters if subprogram is
 	   stubbed since structures are incomplete for the back-end.  */
-	if (gnu_field_list
-	    && Convention (gnat_entity) != Convention_Stubbed)
-           {
- 	    /* If all types are not complete, defer emission of debug
- 	       information for this record types. Otherwise, we risk emitting
- 	       debug information for a dummy type contained in the fields
-	       for that record.  */
+	if (gnu_field_list && Convention (gnat_entity) != Convention_Stubbed)
 	  finish_record_type (gnu_return_type, nreverse (gnu_field_list),
- 			        false, defer_incomplete_level);
-
- 	    if (defer_incomplete_level)
- 	      {
- 	        debug_deferred = true;
- 	        defer_debug_level++;
-
-	        defer_debug_incomplete_list
-		  = tree_cons (NULL_TREE, gnu_return_type,
-			       defer_debug_incomplete_list);
- 	      }
- 	  }
+			      0, false);
 
 	/* If we have a CICO list but it has only one entry, we convert
 	   this function into a function that simply returns that one
@@ -3794,22 +3700,21 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	  gnu_return_type = TREE_TYPE (TREE_PURPOSE (gnu_return_list));
 
 	if (Has_Stdcall_Convention (gnat_entity))
-	  {
-	    struct attrib *attr
-	      = (struct attrib *) xmalloc (sizeof (struct attrib));
-
-	    attr->next = attr_list;
-	    attr->type = ATTR_MACHINE_ATTRIBUTE;
-	    attr->name = get_identifier ("stdcall");
-	    attr->args = NULL_TREE;
-	    attr->error_point = gnat_entity;
-	    attr_list = attr;
-	  }
+	  prepend_one_attribute_to
+	    (&attr_list, ATTR_MACHINE_ATTRIBUTE,
+	     get_identifier ("stdcall"), NULL_TREE,
+	     gnat_entity);
 
-	/* Both lists ware built in reverse.  */
+	/* The lists have been built in reverse.  */
 	gnu_param_list = nreverse (gnu_param_list);
+	if (has_stub)
+	  gnu_stub_param_list = nreverse (gnu_stub_param_list);
 	gnu_return_list = nreverse (gnu_return_list);
 
+	if (Ekind (gnat_entity) == E_Function)
+	  Set_Mechanism (gnat_entity,
+			 (returns_by_ref || returns_unconstrained
+			  ? By_Reference : By_Copy));
 	gnu_type
 	  = create_subprog_type (gnu_return_type, gnu_param_list,
 				 gnu_return_list, returns_unconstrained,
@@ -3817,6 +3722,14 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 				 Function_Returns_With_DSP (gnat_entity),
 				 returns_by_target_ptr);
 
+	if (has_stub)
+	  gnu_stub_type
+	    = create_subprog_type (gnu_return_type, gnu_stub_param_list,
+				   gnu_return_list, returns_unconstrained,
+				   returns_by_ref,
+				   Function_Returns_With_DSP (gnat_entity),
+				   returns_by_target_ptr);
+
 	/* A subprogram (something that doesn't return anything) shouldn't
 	   be considered Pure since there would be no reason for such a
 	   subprogram.  Note that procedures with Out (or In Out) parameters
@@ -3841,6 +3754,14 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 
 	Sloc_to_locus (Sloc (gnat_entity), &input_location);
 
+	if (has_stub)
+	  gnu_stub_type
+	    = build_qualified_type (gnu_stub_type,
+				    TYPE_QUALS (gnu_stub_type)
+				    | (Exception_Mechanism == Back_End_Exceptions
+				       ? TYPE_QUAL_CONST * pure_flag : 0)
+				    | (TYPE_QUAL_VOLATILE * volatile_flag));
+
 	/* If we have a builtin decl for that function, check the signatures
 	   compatibilities.  If the signatures are compatible, use the builtin
 	   decl.  If they are not, we expect the checker predicate to have
@@ -3900,16 +3821,33 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	else if (kind == E_Subprogram_Type)
 	  gnu_decl = create_type_decl (gnu_entity_id, gnu_type, attr_list,
 				       !Comes_From_Source (gnat_entity),
-				       debug_info_p && !defer_incomplete_level,
-				       gnat_entity);
+				       debug_info_p, gnat_entity);
 	else
 	  {
+	    if (has_stub)
+	      {
+		gnu_stub_name = gnu_ext_name;
+		gnu_ext_name = create_concat_name (gnat_entity, "internal");
+		public_flag = false;
+	      }
+
 	    gnu_decl = create_subprog_decl (gnu_entity_id, gnu_ext_name,
 					    gnu_type, gnu_param_list,
 					    inline_flag, public_flag,
 					    extern_flag, attr_list,
 					    gnat_entity);
+	    if (has_stub)
+	      {
+		tree gnu_stub_decl
+		  = create_subprog_decl (gnu_entity_id, gnu_stub_name,
+					 gnu_stub_type, gnu_stub_param_list,
+					 inline_flag, true,
+					 extern_flag, attr_list,
+					 gnat_entity);
+		SET_DECL_FUNCTION_STUB (gnu_decl, gnu_stub_decl);
+	      }
 
+	    /* This is unrelated to the stub built right above.  */
 	    DECL_STUBBED_P (gnu_decl)
 	      = Convention (gnat_entity) == Convention_Stubbed;
 	  }
@@ -3991,13 +3929,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
       /* Simple class_wide types are always viewed as their root_type
 	 by Gigi unless an Equivalent_Type is specified.  */
     case E_Class_Wide_Type:
-      if (Present (Equivalent_Type (gnat_entity)))
-	gnu_decl = gnat_to_gnu_entity (Equivalent_Type (gnat_entity),
-				       NULL_TREE, 0);
-      else
-	gnu_decl = gnat_to_gnu_entity (Root_Type (gnat_entity),
-				       NULL_TREE, 0);
-
+      gnu_decl = gnat_to_gnu_entity (gnat_equiv_type, NULL_TREE, 0);
       maybe_present = true;
       break;
 
@@ -4005,10 +3937,10 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
     case E_Task_Subtype:
     case E_Protected_Type:
     case E_Protected_Subtype:
-      if (type_annotate_only && No (Corresponding_Record_Type (gnat_entity)))
+      if (type_annotate_only && No (gnat_equiv_type))
 	gnu_type = void_type_node;
       else
-	gnu_type = gnat_to_gnu_type (Corresponding_Record_Type (gnat_entity));
+	gnu_type = gnat_to_gnu_type (gnat_equiv_type);
 
       maybe_present = true;
       break;
@@ -4206,9 +4138,12 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
       if (Is_Atomic (gnat_entity))
 	check_ok_for_atomic (gnu_type, gnat_entity, false);
 
-      if (Known_Alignment (gnat_entity))
+      if (Present (Alignment_Clause (gnat_entity)))
 	TYPE_USER_ALIGN (gnu_type) = 1;
 
+      if (Universal_Aliasing (gnat_entity))
+	TYPE_UNIVERSAL_ALIASING_P (TYPE_MAIN_VARIANT (gnu_type)) = 1;
+
       if (!gnu_decl)
 	gnu_decl = create_type_decl (gnu_entity_id, gnu_type, attr_list,
 				     !Comes_From_Source (gnat_entity),
@@ -4243,9 +4178,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	      /* In this mode the tag and the parent components are not
 		 generated by the front-end, so the sizes must be adjusted
 		 explicitly now. */
-
-             int size_offset;
-             int new_size;
+	      int size_offset, new_size;
 
 	      if (Is_Derived_Type (gnat_entity))
 		{
@@ -4321,12 +4254,23 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 
   /* If we deferred processing of incomplete types, re-enable it.  If there
      were no other disables and we have some to process, do so.  */
-  if (this_deferred && --defer_incomplete_level == 0 && defer_incomplete_list)
+  if (this_deferred && --defer_incomplete_level == 0)
     {
-      struct incomplete *incp = defer_incomplete_list;
-      struct incomplete *next;
+      if (defer_incomplete_list)
+	{
+	  struct incomplete *incp, *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;
 	  defer_incomplete_list = NULL;
+
+	  /* For finalization, however, all types must be complete so we
+	     cannot do the same because deferred incomplete types may end up
+	     referencing each other.  Process them all recursively first.  */
+	  defer_finalize_level++;
+
 	  for (; incp; incp = next)
 	    {
 	      next = incp->next;
@@ -4336,6 +4280,23 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 				   gnat_to_gnu_type (incp->full_type));
 	      free (incp);
 	    }
+
+	  defer_finalize_level--;
+	}
+
+      /* All the deferred incomplete types have been processed so we can
+	 now proceed with the finalization of the deferred types.  */
+      if (defer_finalize_level == 0 && defer_finalize_list)
+	{
+	  int toplev = global_bindings_p ();
+	  unsigned int i;
+	  tree t;
+
+	  for (i = 0; VEC_iterate (tree, defer_finalize_list, i, t); i++)
+	    rest_of_decl_compilation (t, toplev, 0);
+
+	  VEC_free (tree, heap, defer_finalize_list);
+	}
     }
 
   /* If we are not defining this type, see if it's in the incomplete list.
@@ -4353,31 +4314,6 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	  }
     }
 
-   /* If there are no incomplete types and we have deferred emission
-      of debug information, check whether we have finished defining
-      all nested records.
-      If so, handle the list now.  */
-
-   if (debug_deferred)
-     defer_debug_level--;
-
-   if (defer_debug_incomplete_list
-       && !defer_incomplete_level
-       && !defer_debug_level)
-    {
-      tree c, n;
-
-      defer_debug_incomplete_list = nreverse (defer_debug_incomplete_list);
-
-      for (c = defer_debug_incomplete_list; c; c = n)
-	{
-	  n = TREE_CHAIN (c);
-	  write_record_type_debug_info (TREE_VALUE (c));
-	}
-
-      defer_debug_incomplete_list = 0;
-    }
-
   if (this_global)
     force_global--;
 
@@ -4404,10 +4340,262 @@ gnat_to_gnu_field_decl (Entity_Id gnat_entity)
   return gnu_field;
 }
 
+/* Wrap up compilation of T, a TYPE_DECL, possibly deferring it.  */
+
+void
+rest_of_type_decl_compilation (tree t)
+{
+  /* We need to defer finalizing the type if incomplete types
+     are being deferred or if they are being processed.  */
+  if (defer_incomplete_level || defer_finalize_level)
+    VEC_safe_push (tree, heap, defer_finalize_list, t);
+  else
+    rest_of_decl_compilation (t, global_bindings_p (), 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.  */
+
+void
+finalize_from_with_types (void)
+{
+  struct incomplete *incp = defer_limited_with;
+  struct incomplete *next;
+
+  defer_limited_with = 0;
+  for (; incp; incp = next)
+    {
+      next = incp->next;
+
+      if (incp->old_type != 0)
+	update_pointer_to (TYPE_MAIN_VARIANT (incp->old_type),
+			   gnat_to_gnu_type (incp->full_type));
+      free (incp);
+    }
+}
+
+/* Return the equivalent type to be used for GNAT_ENTITY, if it's a
+   kind of type (such E_Task_Type) that has a different type which Gigi
+   uses for its representation.  If the type does not have a special type
+   for its representation, return GNAT_ENTITY.  If a type is supposed to
+   exist, but does not, abort unless annotating types, in which case
+   return Empty.  If GNAT_ENTITY is Empty, return Empty.  */
+
+Entity_Id
+Gigi_Equivalent_Type (Entity_Id gnat_entity)
+{
+  Entity_Id gnat_equiv = gnat_entity;
+
+  if (No (gnat_entity))
+    return gnat_entity;
+
+  switch (Ekind (gnat_entity))
+    {
+    case E_Class_Wide_Subtype:
+      if (Present (Equivalent_Type (gnat_entity)))
+	gnat_equiv = Equivalent_Type (gnat_entity);
+      break;
+
+    case E_Access_Protected_Subprogram_Type:
+    case E_Anonymous_Access_Protected_Subprogram_Type:
+      gnat_equiv = Equivalent_Type (gnat_entity);
+      break;
+
+    case E_Class_Wide_Type:
+      gnat_equiv = ((Present (Equivalent_Type (gnat_entity)))
+		    ? Equivalent_Type (gnat_entity)
+		    : Root_Type (gnat_entity));
+      break;
+
+    case E_Task_Type:
+    case E_Task_Subtype:
+    case E_Protected_Type:
+    case E_Protected_Subtype:
+      gnat_equiv = Corresponding_Record_Type (gnat_entity);
+      break;
+
+    default:
+      break;
+    }
+
+  gcc_assert (Present (gnat_equiv) || type_annotate_only);
+  return gnat_equiv;
+}
+
+/* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
+   using MECH as its passing mechanism, to be placed in the parameter
+   list built for GNAT_SUBPROG.  Assume a foreign convention for the
+   latter if FOREIGN is true.  Also set CICO to true if the parameter
+   must use the copy-in copy-out implementation mechanism.
+
+   The returned tree is a PARM_DECL, except for those cases where no
+   parameter needs to be actually passed to the subprogram; the type
+   of this "shadow" parameter is then returned instead.  */
+
+static tree
+gnat_to_gnu_param (Entity_Id gnat_param, Mechanism_Type mech,
+		   Entity_Id gnat_subprog, bool foreign, bool *cico)
+{
+  tree gnu_param_name = get_entity_name (gnat_param);
+  tree gnu_param_type = gnat_to_gnu_type (Etype (gnat_param));
+  bool in_param = (Ekind (gnat_param) == E_In_Parameter);
+  bool by_return = false, by_component_ptr = false, by_ref = false;
+  tree gnu_param;
+
+  /* Copy-return is used only for the first parameter of a valued procedure.
+     It's a copy mechanism for which a parameter is never allocated.  */
+  if (mech == By_Copy_Return)
+    {
+      gcc_assert (Ekind (gnat_param) == E_Out_Parameter);
+      mech = By_Copy;
+      by_return = true;
+    }
+
+  /* If this is either a foreign function or if the underlying type won't
+     be passed by reference, strip off possible padding type.  */
+  if (TREE_CODE (gnu_param_type) == RECORD_TYPE
+      && TYPE_IS_PADDING_P (gnu_param_type))
+    {
+      tree unpadded_type = TREE_TYPE (TYPE_FIELDS (gnu_param_type));
+
+      if (mech == By_Reference
+	  || foreign
+	  || (!must_pass_by_ref (unpadded_type)
+	      && (mech == By_Copy || !default_pass_by_ref (unpadded_type))))
+	gnu_param_type = unpadded_type;
+    }
+
+  /* If this is an IN parameter, it is read-only, so make a variant of the
+     type that is read-only.  ??? However, if this is an unconstrained array,
+     that type can be very complex, so skip it for now.  Likewise for any
+     other self-referential type.  */
+  if (in_param
+      && TREE_CODE (gnu_param_type) != UNCONSTRAINED_ARRAY_TYPE
+      && !CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_param_type)))
+    gnu_param_type = build_qualified_type (gnu_param_type,
+					   (TYPE_QUALS (gnu_param_type)
+					    | TYPE_QUAL_CONST));
+
+  /* For foreign conventions, pass arrays as pointers to the element type.
+     First check for unconstrained array and get the underlying array.  */
+  if (foreign && TREE_CODE (gnu_param_type) == UNCONSTRAINED_ARRAY_TYPE)
+    gnu_param_type
+      = TREE_TYPE (TREE_TYPE (TYPE_FIELDS (TREE_TYPE (gnu_param_type))));
+
+  /* VMS descriptors are themselves passed by reference.  */
+  if (mech == By_Descriptor)
+    gnu_param_type
+      = build_pointer_type (build_vms_descriptor (gnu_param_type,
+						  Mechanism (gnat_param),
+						  gnat_subprog));
+
+  /* Arrays are passed as pointers to element type for foreign conventions.  */
+  else if (foreign
+	   && mech != By_Copy
+	   && TREE_CODE (gnu_param_type) == ARRAY_TYPE)
+    {
+      /* Strip off any multi-dimensional entries, then strip
+	 off the last array to get the component type.  */
+      while (TREE_CODE (TREE_TYPE (gnu_param_type)) == ARRAY_TYPE
+	     && TYPE_MULTI_ARRAY_P (TREE_TYPE (gnu_param_type)))
+	gnu_param_type = TREE_TYPE (gnu_param_type);
+
+      by_component_ptr = true;
+      gnu_param_type = TREE_TYPE (gnu_param_type);
+
+      if (in_param)
+	gnu_param_type = build_qualified_type (gnu_param_type,
+					       (TYPE_QUALS (gnu_param_type)
+						| TYPE_QUAL_CONST));
+
+      gnu_param_type = build_pointer_type (gnu_param_type);
+    }
+
+  /* Fat pointers are passed as thin pointers for foreign conventions.  */
+  else if (foreign && TYPE_FAT_POINTER_P (gnu_param_type))
+    gnu_param_type
+      = make_type_from_size (gnu_param_type, size_int (POINTER_SIZE), 0);
+
+  /* If we must pass or were requested to pass by reference, do so.
+     If we were requested to pass by copy, do so.
+     Otherwise, for foreign conventions, pass IN OUT or OUT parameters
+     or aggregates by reference.  For COBOL and Fortran, pass all
+     integer and FP types that way too.  For Convention Ada, use
+     the standard Ada default.  */
+  else if (must_pass_by_ref (gnu_param_type)
+	   || mech == By_Reference
+	   || (mech != By_Copy
+	       && ((foreign
+		    && (!in_param || AGGREGATE_TYPE_P (gnu_param_type)))
+		   || (foreign
+		       && (Convention (gnat_subprog) == Convention_Fortran
+			   || Convention (gnat_subprog) == Convention_COBOL)
+		       && (INTEGRAL_TYPE_P (gnu_param_type)
+			   || FLOAT_TYPE_P (gnu_param_type)))
+		   || (!foreign
+		       && default_pass_by_ref (gnu_param_type)))))
+    {
+      gnu_param_type = build_reference_type (gnu_param_type);
+      by_ref = true;
+    }
+
+  /* Pass IN OUT or OUT parameters using copy-in copy-out mechanism.  */
+  else if (!in_param)
+    *cico = true;
+
+  if (mech == By_Copy && (by_ref || by_component_ptr))
+    post_error ("?cannot pass & by copy", gnat_param);
+
+  /* If this is an OUT parameter that isn't passed by reference and isn't
+     a pointer or aggregate, we don't make a PARM_DECL for it.  Instead,
+     it will be a VAR_DECL created when we process the procedure, so just
+     return its type.  For the special parameter of a valued procedure,
+     never pass it in.
+
+     An exception is made to cover the RM-6.4.1 rule requiring "by copy"
+     OUT parameters with discriminants or implicit initial values to be
+     handled like IN OUT parameters.  These type are normally built as
+     aggregates, hence passed by reference, except for some packed arrays
+     which end up encoded in special integer types.
+
+     The exception we need to make is then for packed arrays of records
+     with discriminants or implicit initial values.  We have no light/easy
+     way to check for the latter case, so we merely check for packed arrays
+     of records.  This may lead to useless copy-in operations, but in very
+     rare cases only, as these would be exceptions in a set of already
+     exceptional situations.  */
+  if (Ekind (gnat_param) == E_Out_Parameter
+      && !by_ref
+      && (by_return
+	  || (mech != By_Descriptor
+	      && !POINTER_TYPE_P (gnu_param_type)
+	      && !AGGREGATE_TYPE_P (gnu_param_type)))
+      && !(Is_Array_Type (Etype (gnat_param))
+	   && Is_Packed (Etype (gnat_param))
+	   && Is_Composite_Type (Component_Type (Etype (gnat_param)))))
+    return gnu_param_type;
+
+  gnu_param = create_param_decl (gnu_param_name, gnu_param_type,
+				 by_ref || by_component_ptr || in_param);
+  DECL_BY_REF_P (gnu_param) = by_ref;
+  DECL_BY_COMPONENT_PTR_P (gnu_param) = by_component_ptr;
+  DECL_BY_DESCRIPTOR_P (gnu_param) = (mech == By_Descriptor);
+  DECL_POINTS_TO_READONLY_P (gnu_param)
+    = (in_param && (by_ref || by_component_ptr));
+
+  /* If no Mechanism was specified, indicate what we're using, then
+     back-annotate it.  */
+  if (mech == Default)
+    mech = (by_ref || by_component_ptr) ? By_Reference : By_Copy;
+
+  Set_Mechanism (gnat_param, mech);
+  return gnu_param;
+}
+
 /* Return true if DISCR1 and DISCR2 represent the same discriminant.  */
 
-static
-bool same_discriminant_p (Entity_Id discr1, Entity_Id discr2)
+static bool
+same_discriminant_p (Entity_Id discr1, Entity_Id discr2)
 {
   while (Present (Corresponding_Discriminant (discr1)))
     discr1 = Corresponding_Discriminant (discr1);
@@ -4621,6 +4809,27 @@ allocatable_size_p (tree gnu_size, bool static_p)
   return (int) our_size == our_size;
 }
 
+/* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
+   NAME, ARGS and ERROR_POINT.  */
+
+static void
+prepend_one_attribute_to (struct attrib ** attr_list,
+			  enum attr_type attr_type,
+			  tree attr_name,
+			  tree attr_args,
+			  Node_Id attr_error_point)
+{
+  struct attrib * attr = (struct attrib *) xmalloc (sizeof (struct attrib));
+
+  attr->type = attr_type;
+  attr->name = attr_name;
+  attr->args = attr_args;
+  attr->error_point = attr_error_point;
+
+  attr->next = *attr_list;
+  *attr_list = attr;
+}
+
 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any.  */
 
 static void
@@ -4632,7 +4841,6 @@ prepend_attributes (Entity_Id gnat_entity, struct attrib ** attr_list)
        gnat_temp = Next_Rep_Item (gnat_temp))
     if (Nkind (gnat_temp) == N_Pragma)
       {
-	struct attrib *attr;
 	tree gnu_arg0 = NULL_TREE, gnu_arg1 = NULL_TREE;
 	Node_Id gnat_assoc = Pragma_Argument_Associations (gnat_temp);
 	enum attr_type etype;
@@ -4686,23 +4894,16 @@ prepend_attributes (Entity_Id gnat_entity, struct attrib ** attr_list)
 	    continue;
 	  }
 
-	attr = (struct attrib *) xmalloc (sizeof (struct attrib));
-	attr->next = *attr_list;
-	attr->type = etype;
-	attr->name = gnu_arg0;
-
-	/* If we have an argument specified together with an attribute name,
-	   make it a single TREE_VALUE entry in a list of arguments, as GCC
-	   expects it.  */
-	if (gnu_arg1 != NULL_TREE)
-	  attr->args = build_tree_list (NULL_TREE, gnu_arg1);
-	else
-	  attr->args = NULL_TREE;
 
-	attr->error_point
-	  = Present (Next (First (gnat_assoc)))
-	    ? Expression (Next (First (gnat_assoc))) : gnat_temp;
-	*attr_list = attr;
+	/* Prepend to the list now.  Make a list of the argument we might
+	   have, as GCC expects it.  */
+	prepend_one_attribute_to
+	  (attr_list,
+	   etype, gnu_arg0,
+	   (gnu_arg1 != NULL_TREE)
+	   ? build_tree_list (NULL_TREE, gnu_arg1) : NULL_TREE,
+	   Present (Next (First (gnat_assoc)))
+	   ? Expression (Next (First (gnat_assoc))) : gnat_temp);
       }
 }
 
@@ -4853,54 +5054,92 @@ elaborate_expression_1 (Node_Id gnat_expr, Entity_Id gnat_entity,
     return maybe_variable (gnu_expr);
 }
 
-/* Create a record type that contains a field of TYPE with a starting bit
-   position so that it is aligned to ALIGN bits and is SIZE bytes long.  */
+/* Create a record type that contains a SIZE bytes long field of TYPE with a
+   starting bit position so that it is aligned to ALIGN bits, and leaving at
+   least ROOM bytes free before the field.  BASE_ALIGN is the alignment the
+   record is guaranteed to get.  */
 
 tree
-make_aligning_type (tree type, int align, tree size)
+make_aligning_type (tree type, unsigned int align, tree size,
+		    unsigned int base_align, int room)
 {
+  /* We will be crafting a record type with one field at a position set to be
+     the next multiple of ALIGN past record'address + room bytes.  We use a
+     record placeholder to express record'address.  */
+
   tree record_type = make_node (RECORD_TYPE);
-  tree place = build0 (PLACEHOLDER_EXPR, record_type);
-  tree size_addr_place = convert (sizetype,
-				  build_unary_op (ADDR_EXPR, NULL_TREE,
-						  place));
+  tree record = build0 (PLACEHOLDER_EXPR, record_type);
+
+  tree record_addr_st
+    = convert (sizetype, build_unary_op (ADDR_EXPR, NULL_TREE, record));
+
+  /* The diagram below summarizes the shape of what we manipulate:
+
+                    <--------- pos ---------->
+                {  +------------+-------------+-----------------+
+      record  =>{  |############|     ...     | field (type)    |
+                {  +------------+-------------+-----------------+
+		   |<-- room -->|<- voffset ->|<---- size ----->|
+		   o            o
+		   |            |
+		   record_addr  vblock_addr
+
+     Every length is in sizetype bytes there, except "pos" which has to be
+     set as a bit position in the GCC tree for the record.  */
+
+  tree room_st = size_int (room);
+  tree vblock_addr_st = size_binop (PLUS_EXPR, record_addr_st, room_st);
+  tree voffset_st, pos, field;
+
   tree name = TYPE_NAME (type);
-  tree pos, field;
 
   if (TREE_CODE (name) == TYPE_DECL)
     name = DECL_NAME (name);
 
   TYPE_NAME (record_type) = concat_id_with_name (name, "_ALIGN");
 
-  /* The bit position is obtained by "and"ing the alignment minus 1
-     with the two's complement of the address and  multiplying
-     by the number of bits per unit.  Do all this in sizetype.  */
+  /* Compute VOFFSET and then POS.  The next byte position multiple of some
+     alignment after some address is obtained by "and"ing the alignment minus
+     1 with the two's complement of the address.   */
+
+  voffset_st = size_binop (BIT_AND_EXPR,
+			   size_diffop (size_zero_node, vblock_addr_st),
+			   ssize_int ((align / BITS_PER_UNIT) - 1));
+
+  /* POS = (ROOM + VOFFSET) * BIT_PER_UNIT, in bitsizetype.  */
+
   pos = size_binop (MULT_EXPR,
 		    convert (bitsizetype,
-			     size_binop (BIT_AND_EXPR,
-					 size_diffop (size_zero_node,
-						      size_addr_place),
-					 ssize_int ((align / BITS_PER_UNIT)
-						    - 1))),
+			     size_binop (PLUS_EXPR, room_st, voffset_st)),
                     bitsize_unit_node);
 
-  /* Create the field, with -1 as the 'addressable' indication to avoid the
+  /* Craft the GCC record representation.  The sizes are set manually to
+     account for the maximum possible value of voffset, which avoids complex
+     self-references in the size expression and corresponds to what should be
+     "alloc"ated for this type anyway.
+
+     Use -1 as the 'addressable' indication for the field to prevent the
      creation of a bitfield.  We don't need one, it would have damaging
      consequences on the alignment computation, and create_field_decl would
      make one without this special argument, for instance because of the
      complex position expression.  */
-  field = create_field_decl (get_identifier ("F"), type, record_type, 1, size,
-			     pos, -1);
 
-  finish_record_type (record_type, field, true, false);
-  TYPE_ALIGN (record_type) = BIGGEST_ALIGNMENT;
+  field = create_field_decl (get_identifier ("F"), type, record_type,
+                             1, size, pos, -1);
+  TYPE_FIELDS (record_type) = field;
+
+  TYPE_ALIGN (record_type) = base_align;
+  TYPE_USER_ALIGN (record_type) = 1;
+
   TYPE_SIZE (record_type)
     = size_binop (PLUS_EXPR,
                   size_binop (MULT_EXPR, convert (bitsizetype, size),
                               bitsize_unit_node),
-		  bitsize_int (align));
+		  bitsize_int (align + room * BITS_PER_UNIT));
   TYPE_SIZE_UNIT (record_type)
-    = size_binop (PLUS_EXPR, size, size_int (align / BITS_PER_UNIT));
+    = size_binop (PLUS_EXPR, size,
+		  size_int (room + align / BITS_PER_UNIT));
+
   copy_alias_set (record_type, type);
   return record_type;
 }
@@ -4936,6 +5175,7 @@ make_packable_type (tree type)
   TYPE_ALIGN (new_type)
     = ((HOST_WIDE_INT) 1
        << (floor_log2 (tree_low_cst (TYPE_SIZE (type), 1) - 1) + 1));
+  TYPE_USER_ALIGN (new_type) = 1;
 
   /* Now copy the fields, keeping the position and size.  */
   for (old_field = TYPE_FIELDS (type); old_field;
@@ -4969,7 +5209,7 @@ make_packable_type (tree type)
       field_list = new_field;
     }
 
-  finish_record_type (new_type, nreverse (field_list), true, true);
+  finish_record_type (new_type, nreverse (field_list), 1, true);
   copy_alias_set (new_type, type);
   return TYPE_MODE (new_type) == BLKmode ? type : new_type;
 }
@@ -4994,6 +5234,7 @@ maybe_pad_type (tree type, tree size, unsigned int align,
 		bool is_user_type, bool definition, bool same_rm_size)
 {
   tree orig_size = TYPE_SIZE (type);
+  unsigned int orig_align = align;
   tree record;
   tree field;
 
@@ -5087,10 +5328,14 @@ maybe_pad_type (tree type, tree size, unsigned int align,
        : TYPE_SIZE_UNIT (type));
 
   TYPE_ALIGN (record) = align;
+  if (orig_align)
+    TYPE_USER_ALIGN (record) = align;
+
   TYPE_IS_PADDING_P (record) = 1;
   TYPE_VOLATILE (record)
     = Present (gnat_entity) && Treat_As_Volatile (gnat_entity);
-  finish_record_type (record, field, true, false);
+  /* Do not finalize it until after the auxiliary record is built.  */
+  finish_record_type (record, field, 1, true);
 
   /* Keep the RM_Size of the padded record as that of the old record
      if requested.  */
@@ -5117,7 +5362,7 @@ maybe_pad_type (tree type, tree size, unsigned int align,
 			  create_field_decl (orig_name, integer_type_node,
 					     marker, 0, NULL_TREE, NULL_TREE,
 					     0),
-			  false, false);
+			  0, false);
 
       if (size && TREE_CODE (size) != INTEGER_CST && definition)
 	create_var_decl (concat_id_with_name (name, "XVZ"), NULL_TREE,
@@ -5125,12 +5370,18 @@ maybe_pad_type (tree type, tree size, unsigned int align,
 			 false, NULL, gnat_entity);
     }
 
-  type = record;
+  rest_of_record_type_compilation (record);
 
+  /* If the size was widened explicitly, maybe give a warning.  Take the
+     original size as the maximum size of the input if there was an
+     unconstrained record involved and round it up to the specified alignment,
+     if one was specified.  */
   if (CONTAINS_PLACEHOLDER_P (orig_size))
     orig_size = max_size (orig_size, true);
 
-  /* If the size was widened explicitly, maybe give a warning.  */
+  if (align)
+    orig_size = round_up (orig_size, align);
+
   if (size && Present (gnat_entity)
       && !operand_equal_p (size, orig_size, 0)
       && !(TREE_CODE (size) == INTEGER_CST
@@ -5163,7 +5414,7 @@ maybe_pad_type (tree type, tree size, unsigned int align,
 			    size_diffop (size, orig_size));
     }
 
-  return type;
+  return record;
 }
 
 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
@@ -5253,11 +5504,36 @@ choices_to_gnu (tree operand, Node_Id choices)
   return result;
 }
 
+/* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
+   type FIELD_TYPE to be placed in RECORD_TYPE.  Return the result.  */
+
+static int
+adjust_packed (tree field_type, tree record_type, int packed)
+{
+  /* If the field contains an item of variable size, we cannot pack it
+     because we cannot create temporaries of non-fixed size.  */
+  if (is_variable_size (field_type))
+    return 0;
+
+  /* If the alignment of the record is specified and the field type
+     is over-aligned, request Storage_Unit alignment for the field.  */
+  if (packed == -2)
+    {
+      if (TYPE_ALIGN (field_type) > TYPE_ALIGN (record_type))
+	return -1;
+      else
+	return 0;
+    }
+
+  return packed;
+}
+
 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
    placed in GNU_RECORD_TYPE.
 
-   PACKED is 1 if the enclosing record is packed and -1 if the enclosing
-   record has a Component_Alignment of Storage_Unit.
+   PACKED is 1 if the enclosing record is packed, -1 if the enclosing
+   record has Component_Alignment of Storage_Unit, -2 if the enclosing
+   record has a specified alignment.
 
    DEFINITION is true if this field is for a record being defined.  */
 
@@ -5274,10 +5550,12 @@ gnat_to_gnu_field (Entity_Id gnat_field, tree gnu_record_type, int packed,
     = (Is_Aliased (gnat_field) || Strict_Alignment (Etype (gnat_field))
        || Treat_As_Volatile (gnat_field));
 
-  /* If this field requires strict alignment or contains an item of
-     variable sized, pretend it isn't packed.  */
-  if (needs_strict_alignment || is_variable_size (gnu_field_type))
+  /* If this field requires strict alignment, we cannot pack it because
+     it would very likely be under-aligned in the record.  */
+  if (needs_strict_alignment)
     packed = 0;
+  else
+    packed = adjust_packed (gnu_field_type, gnu_record_type, packed);
 
   /* For packed records, this is one of the few occasions on which we use
      the official RM size for discrete or fixed-point components, instead
@@ -5334,24 +5612,21 @@ gnat_to_gnu_field (Entity_Id gnat_field, tree gnu_record_type, int packed,
 	      % BITS_PER_UNIT == 0);
 
       /* Compute whether we should avoid the substitution.  */
-      int reject =
-        /* There is no point substituting if there is no change.  */
-        (gnu_packable_type == gnu_field_type
-         ||
+      bool reject
+	/* There is no point substituting if there is no change...  */
+	= (gnu_packable_type == gnu_field_type)
 	 /* ... nor when the field is known to be byte aligned and not to
 	    share a byte with another field.  */
-	 (has_byte_aligned_clause
+	  || (has_byte_aligned_clause
 	      && value_factor_p (gnu_size, BITS_PER_UNIT))
-	 ||
 	 /* The size of an aliased field must be an exact multiple of the
 	    type's alignment, which the substitution might increase.  Reject
 	    substitutions that would so invalidate a component clause when the
 	    specified position is byte aligned, as the change would have no
 	    real benefit from the packing standpoint anyway.  */
-         (Is_Aliased (gnat_field)
+	  || (Is_Aliased (gnat_field)
 	      && has_byte_aligned_clause
-          && ! value_factor_p (gnu_size, TYPE_ALIGN (gnu_packable_type)))
-	 );
+	      && !value_factor_p (gnu_size, TYPE_ALIGN (gnu_packable_type)));
 
       /* Substitute unless told otherwise.  */
       if (!reject)
@@ -5554,6 +5829,19 @@ is_variable_size (tree type)
   return false;
 }
 
+/* qsort comparer for the bit positions of two record components.  */
+
+static int
+compare_field_bitpos (const PTR rt1, const PTR rt2)
+{
+  tree field1 = * (tree *) rt1;
+  tree field2 = * (tree *) rt2;
+  int ret;
+
+  ret = tree_int_cst_compare (bit_position (field1), bit_position (field2));
+  return ret ? ret : (int) (DECL_UID (field1) - DECL_UID (field2));
+}
+
 /* Return a GCC tree for a record type given a GNAT Component_List and a chain
    of GCC trees for fields that are in the record and have already been
    processed.  When called from gnat_to_gnu_entity during the processing of a
@@ -5561,8 +5849,9 @@ is_variable_size (tree type)
    the chain.  The other calls to this function are recursive calls from
    itself for the Component_List of a variant and the chain is empty.
 
-   PACKED is 1 if this is for a record with "pragma pack" and -1 is this is
-   for a record type with "pragma component_alignment (storage_unit)".
+   PACKED is 1 if this is for a packed record, -1 if this is for a record
+   with Component_Alignment of Storage_Unit, -2 if this is for a record
+   with a specified alignment.
 
    DEFINITION is true if we are defining this record.
 
@@ -5578,10 +5867,10 @@ is_variable_size (tree type)
    ALL_REP, if true, means a rep clause was found for all the fields.  This
    simplifies the logic since we know we're not in the mixed case.
 
-   DEFER_DEBUG, if true, means that the debugging routines should not be
-   called when finishing constructing the record type.
+   DO_NOT_FINALIZE, if true, means that the record type is expected to be
+   modified afterwards so it will not be sent to the back-end for finalization.
 
-   UNCHECKED_UNION, if tree, means that we are building a type for a record
+   UNCHECKED_UNION, if true, means that we are building a type for a record
    with a Pragma Unchecked_Union.
 
    The processing of the component list fills in the chain with all of the
@@ -5591,7 +5880,7 @@ static void
 components_to_record (tree gnu_record_type, Node_Id component_list,
 		      tree gnu_field_list, int packed, bool definition,
 		      tree *p_gnu_rep_list, bool cancel_alignment,
-		      bool all_rep, bool defer_debug, bool unchecked_union)
+		      bool all_rep, bool do_not_finalize, bool unchecked_union)
 {
   Node_Id component_decl;
   Entity_Id gnat_field;
@@ -5603,7 +5892,6 @@ components_to_record (tree gnu_record_type, Node_Id component_list,
 
   /* For each variable within each component declaration create a GCC field
      and add it to the list, skipping any pragmas in the list.  */
-
   if (Present (Component_Items (component_list)))
     for (component_decl = First_Non_Pragma (Component_Items (component_list));
 	 Present (component_decl);
@@ -5705,8 +5993,8 @@ components_to_record (tree gnu_record_type, Node_Id component_list,
 		= TYPE_SIZE_UNIT (gnu_record_type);
 	    }
 
-	  /* Create the record for the variant.  Note that we defer emitting
-	     debug info for it until after we are sure to actually use it.  */
+	  /* Create the record type for the variant.  Note that we defer
+	     finalizing it until after we are sure to actually use it.  */
 	  components_to_record (gnu_variant_type, Component_List (variant),
 				NULL_TREE, packed, definition,
 				&gnu_our_rep_list, !all_rep_and_size, all_rep,
@@ -5724,17 +6012,21 @@ components_to_record (tree gnu_record_type, Node_Id component_list,
 	    gnu_field = TYPE_FIELDS (gnu_variant_type);
 	  else
 	    {
-	      /* Emit debug info for the record.  We used to throw away
+	      /* Deal with packedness like in gnat_to_gnu_field.  */
+	      int field_packed
+		= adjust_packed (gnu_variant_type, gnu_record_type, packed);
+
+	      /* Finalize the record type now.  We used to throw away
 		 empty records but we no longer do that because we need
 		 them to generate complete debug info for the variant;
 		 otherwise, the union type definition will be lacking
 		 the fields associated with these empty variants.  */
-	      write_record_type_debug_info (gnu_variant_type);
+	      rest_of_record_type_compilation (gnu_variant_type);
 
 	      gnu_field = create_field_decl (gnu_inner_name, gnu_variant_type,
-					     gnu_union_type, 0,
+					     gnu_union_type, field_packed,
 					     (all_rep_and_size
-					      ? TYPE_SIZE (gnu_record_type)
+					      ? TYPE_SIZE (gnu_variant_type)
 					      : 0),
 					     (all_rep_and_size
 					      ? bitsize_zero_node : 0),
@@ -5761,7 +6053,7 @@ components_to_record (tree gnu_record_type, Node_Id component_list,
 	    }
 
 	  finish_record_type (gnu_union_type, nreverse (gnu_variant_list),
-			      all_rep_and_size, false);
+			      all_rep_and_size ? 1 : 0, false);
 
 	  /* If GNU_UNION_TYPE is our record type, it means we must have an
 	     Unchecked_Union with no fields.  Verify that and, if so, just
@@ -5791,7 +6083,6 @@ components_to_record (tree gnu_record_type, Node_Id component_list,
 
      ??? Note: if we then reorder them, debugging information will be wrong,
      but there's nothing that can be done about this at the moment.  */
-
   for (gnu_field = gnu_field_list, gnu_last = NULL_TREE; gnu_field; )
     {
       if (DECL_FIELD_OFFSET (gnu_field))
@@ -5847,7 +6138,7 @@ components_to_record (tree gnu_record_type, Node_Id component_list,
 
       if (gnu_field_list)
 	{
-	  finish_record_type (gnu_rep_type, gnu_our_rep_list, true, false);
+	  finish_record_type (gnu_rep_type, gnu_our_rep_list, 1, false);
 	  gnu_field = create_field_decl (get_identifier ("REP"), gnu_rep_type,
 					 gnu_record_type, 0, 0, 0, 1);
 	  DECL_INTERNAL_P (gnu_field) = 1;
@@ -5864,25 +6155,7 @@ components_to_record (tree gnu_record_type, Node_Id component_list,
     TYPE_ALIGN (gnu_record_type) = 0;
 
   finish_record_type (gnu_record_type, nreverse (gnu_field_list),
-		      layout_with_rep, defer_debug);
-}
-
-/* Called via qsort from the above.  Returns -1, 1, depending on the
-   bit positions and ordinals of the two fields.  Use DECL_UID to ensure
-   a stable sort.  */
-
-static int
-compare_field_bitpos (const PTR rt1, const PTR rt2)
-{
-  tree *t1 = (tree *) rt1;
-  tree *t2 = (tree *) rt2;
-
-  if (tree_int_cst_equal (bit_position (*t1), bit_position (*t2)))
-    return DECL_UID (*t1) < DECL_UID (*t2) ? -1 : 1;
-  else if (tree_int_cst_lt (bit_position (*t1), bit_position (*t2)))
-    return -1;
-  else
-    return 1;
+		      layout_with_rep ? 1 : 0, do_not_finalize);
 }
 
 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
@@ -6656,6 +6929,7 @@ gnat_substitute_in_type (tree t, tree f, tree r)
 	TYPE_CONVENTION_FORTRAN_P (new) = TYPE_CONVENTION_FORTRAN_P (t);
 	layout_type (new);
 	TYPE_ALIGN (new) = TYPE_ALIGN (t);
+	TYPE_USER_ALIGN (new) = TYPE_USER_ALIGN (t);
 
 	/* If we had bounded the sizes of T by a constant, bound the sizes of
 	   NEW by the same constant.  */