2013-12-04 Eric Botcazou <ebotcazou@adacore.com>
+ * gcc-interface/decl.c (components_to_record): Add specific handling
+ for fields with zero size and no representation clause.
+
+2013-12-04 Eric Botcazou <ebotcazou@adacore.com>
+
* gcc-interface/trans.c (Case_Statement_to_gnu): Do not push a binding
level for each branch if this is a case expression in Ada 2012.
(gnat_to_gnu) <case N_Expression_With_Actions>: Adjust comment.
tree gnu_rep_list = NULL_TREE;
tree gnu_var_list = NULL_TREE;
tree gnu_self_list = NULL_TREE;
+ tree gnu_zero_list = NULL_TREE;
/* For each component referenced in a component declaration create a GCC
field and add it to the list, skipping pragmas in the GNAT list. */
to do this in a separate pass since we want to handle the discriminants
but can't play with them until we've used them in debugging data above.
+ Similarly, pull out the fields with zero size and no rep clause, as they
+ would otherwise modify the layout and thus very likely run afoul of the
+ Ada semantics, which are different from those of C here.
+
??? If we reorder them, debugging information will be wrong but there is
nothing that can be done about this at the moment. */
gnu_last = NULL_TREE;
continue;
}
+ if (DECL_SIZE (gnu_field) && integer_zerop (DECL_SIZE (gnu_field)))
+ {
+ DECL_FIELD_OFFSET (gnu_field) = size_zero_node;
+ SET_DECL_OFFSET_ALIGN (gnu_field, BIGGEST_ALIGNMENT);
+ DECL_FIELD_BIT_OFFSET (gnu_field) = bitsize_zero_node;
+ if (field_is_aliased (gnu_field))
+ TYPE_ALIGN (gnu_record_type)
+ = MAX (TYPE_ALIGN (gnu_record_type),
+ TYPE_ALIGN (TREE_TYPE (gnu_field)));
+ MOVE_FROM_FIELD_LIST_TO (gnu_zero_list);
+ continue;
+ }
+
gnu_last = gnu_field;
}
finish_record_type (gnu_record_type, gnu_field_list, layout_with_rep ? 1 : 0,
debug_info && !maybe_unused);
+ /* Chain the fields with zero size at the beginning of the field list. */
+ if (gnu_zero_list)
+ TYPE_FIELDS (gnu_record_type)
+ = chainon (gnu_zero_list, TYPE_FIELDS (gnu_record_type));
+
return (gnu_rep_list && !p_gnu_rep_list) || variants_have_rep;
}
\f
--- /dev/null
+-- { dg-do run }
+
+procedure Pack19 is
+
+ subtype Always_False is Boolean range False .. False;
+
+ type Rec1 is record
+ B1 : Boolean;
+ B2 : Boolean;
+ B3 : Boolean;
+ B4 : Boolean;
+ B5 : Boolean;
+ B6 : Boolean;
+ B7 : Always_False;
+ B8 : Boolean;
+ end record;
+ pragma Pack (Rec1);
+
+ subtype Always_True is Boolean range True .. True;
+
+ type Rec2 is record
+ B1 : Boolean;
+ B2 : Boolean;
+ B3 : Boolean;
+ B4 : Boolean;
+ B5 : Boolean;
+ B6 : Boolean;
+ B7 : Always_True;
+ B8 : Boolean;
+ end record;
+ pragma Pack (Rec2);
+
+ R1 : Rec1 := (True, True, True, True, True, True, False, False);
+ R2 : Rec2 := (False, False, False, False, False, False, True, True);
+
+begin
+ R1.B8 := True;
+ if R1.B7 /= False then
+ raise Program_Error;
+ end if;
+
+ R1.B7 := False;
+ if R1.B7 /= False then
+ raise Program_Error;
+ end if;
+
+ R2.B8 := False;
+ if R2.B7 /= True then
+ raise Program_Error;
+ end if;
+
+ R2.B7 := True;
+ if R2.B7 /= True then
+ raise Program_Error;
+ end if;
+end;