The 6.2(12) paragraph reads:
"If one name denotes a part of a formal parameter, and a second name denotes
a part of a distinct formal parameter or an object that is not part of a
formal parameter, then the two names are considered distinct access paths. If
an object is of a type for which the parameter passing mechanism is not
specified, then it is a bounded error to assign to the object via one access
path, and then read the value of the object via a distinct access path, unless
the first access path denotes a part of a formal parameter that no longer
exists at the point of the second access (due to leaving the corresponding
callable construct). The possible consequences are that Program_Error is
raised, or the newly assigned value is read, or some old value of the object
is read. "
We leverage it to consider that parameters passed by reference at the sole
decision of the compiler are restrict-qualified in the C sense.
Tested on i586-suse-linux, applied on the mainline.
2011-12-11 Eric Botcazou <ebotca...@adacore.com>
* gcc-interface/decl.c (gnat_to_gnu_param): Set the restrict qualifier
on references built for parameters which aren't specifically by-ref.
--
Eric Botcazou
Index: gcc-interface/decl.c
===================================================================
--- gcc-interface/decl.c (revision 182201)
+++ gcc-interface/decl.c (working copy)
@@ -5518,7 +5518,15 @@ gnat_to_gnu_param (Entity_Id gnat_param,
|| (!foreign
&& default_pass_by_ref (gnu_param_type)))))
{
+ /* We take advantage of 6.2(12) by considering that references built for
+ parameters whose type isn't by-ref and for which the mechanism hasn't
+ been forced to by-ref are restrict-qualified in the C sense. */
+ bool restrict_p
+ = !TREE_ADDRESSABLE (gnu_param_type) && mech != By_Reference;
gnu_param_type = build_reference_type (gnu_param_type);
+ if (restrict_p)
+ gnu_param_type
+ = build_qualified_type (gnu_param_type, TYPE_QUAL_RESTRICT);
by_ref = true;
/* In some ABIs, e.g. SPARC 32-bit, fat pointer types are themselves
