On Thu, Mar 8, 2018 at 1:08 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> The reporter complains that -Wformat incorrectly reports std::string* passed
> to "%s" format rather than std::string, which is what the user did.
>
> This transformation of non-trivial copy init or dtor classes in ellipsis is
> done by convert_arg_to_ellipsis; that function does many changes and all
> but this one look desirable for the -Wnonnull/-Wformat/-Wsentinel/-Wrestrict
> warnings. We prepare a special argument vector in any case, so this patch
> just arranges to undo what convert_arg_to_ellipsis did for the classes.
> I think -Wnonnull shouldn't care, because when passing such a class by
> value, it will be non-NULL (and -Wnonnull looks only for literal NULLs
> anyway), -Wrestrict only cares about named arguments and -Wsentinel only
> cares about NULL arguments passed to ellipsis.
I notice that convert_arg_to_ellipsis generates a pointer-typed
expression, whereas convert_for_arg_passing generates a reference.
Does correcting that inconsistency help?
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index f83d51f3457..617ce18f8cd 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -7209,7 +7209,7 @@ convert_arg_to_ellipsis (tree arg, tsubst_flags_t complain)
"passing objects of non-trivially-copyable "
"type %q#T through %<...%> is conditionally supported",
arg_type);
- return cp_build_addr_expr (arg, complain);
+ return build1 (ADDR_EXPR, build_reference_type (arg_type), arg);
}
/* Build up a real lvalue-to-rvalue conversion in case the
copy constructor is trivial but not callable. */
