From: Marek Polacek <polacek@redhat.com>
To: Jason Merrill <jason@redhat.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>,
Jakub Jelinek <jakub@redhat.com>,
"Joseph S. Myers" <joseph@codesourcery.com>
Subject: Re: [PATCH][ubsan] Add VLA bound instrumentation
Date: Wed, 30 Oct 2013 16:20:00 -0000 [thread overview]
Message-ID: <20131030161504.GC31396@redhat.com> (raw)
In-Reply-To: <52712C29.3010206@redhat.com>
On Wed, Oct 30, 2013 at 11:56:25AM -0400, Jason Merrill wrote:
> On 10/30/2013 10:52 AM, Marek Polacek wrote:
> >+ if ((flag_sanitize & SANITIZE_VLA)
> >+ && !processing_template_decl
>
> You don't need to check processing_template_decl; the template case
> was already handled above.
Right, removed.
> >+ tree x = cp_save_expr (size);
> >+ x = build2 (COMPOUND_EXPR, TREE_TYPE (x),
> >+ ubsan_instrument_vla (input_location, x), x);
> >+ finish_expr_stmt (x);
>
> Saving 'size' here doesn't help since it's already been used above.
> Could you use itype instead of size here?
I already experimented with that and I think I can't, since we call
the finish_expr_stmt too soon, which results in:
int x = 1;
int a[0:(sizetype) SAVE_EXPR <D.2143>];
<<cleanup_point int x = 1;>>;
<<cleanup_point <<< Unknown tree: expr_stmt
if (SAVE_EXPR <D.2143> <= 0)
{
__builtin___ubsan_handle_vla_bound_not_positive (&*.Lubsan_data0, (unsigned long) SAVE_EXPR <D.2143>);
}
else
{
0
}, (void) SAVE_EXPR <D.2143>; >>>>>;
ssizetype D.2143;
<<cleanup_point <<< Unknown tree: expr_stmt
(void) (D.2143 = (ssizetype) ++x + -1) >>>>>;
and that ICEs in gimplify_var_or_parm_decl, presumably because the
if (SAVE_EXPR <D.2143> <= 0) { ... } should be emitted *after* that
cleanup_point. When we generated the C++1y check in cp_finish_decl,
we emitted the check after the cleanup_point, and everything was OK.
I admit I don't understand the cleanup_points very much and I don't
know exactly where they are coming from, because normally I don't see
them coming out of C FE. :) Thanks.
Marek
next prev parent reply other threads:[~2013-10-30 16:15 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-12 12:38 Marek Polacek
2013-09-12 12:48 ` Marek Polacek
2013-09-12 16:12 ` Joseph S. Myers
2013-09-12 16:20 ` Joseph S. Myers
2013-09-12 17:15 ` Marek Polacek
2013-09-13 10:29 ` Marek Polacek
2013-09-13 11:23 ` Eric Botcazou
2013-09-13 18:01 ` Joseph S. Myers
2013-09-16 11:13 ` Marek Polacek
2013-09-16 13:39 ` Florian Weimer
2013-09-12 16:29 ` Marek Polacek
2013-09-25 13:23 ` Marek Polacek
2013-10-07 20:17 ` Marek Polacek
2013-10-15 13:25 ` Marek Polacek
2013-10-15 15:01 ` Joseph S. Myers
2013-10-24 20:35 ` Jason Merrill
2013-10-25 17:38 ` Marek Polacek
2013-10-25 19:04 ` Jason Merrill
2013-10-25 19:15 ` Marek Polacek
2013-10-25 19:30 ` Jason Merrill
2013-10-30 15:16 ` Marek Polacek
2013-10-30 16:08 ` Jason Merrill
2013-10-30 16:20 ` Marek Polacek [this message]
2013-10-30 20:55 ` Mike Stump
2013-10-30 22:46 ` Marek Polacek
2013-10-30 22:50 ` Mike Stump
2013-10-31 11:12 ` Marek Polacek
2013-10-31 3:18 ` Jason Merrill
2013-10-31 19:07 ` Marek Polacek
2013-11-01 17:35 ` Jason Merrill
2013-11-01 19:10 ` Marek Polacek
2013-11-01 20:39 ` Jason Merrill
2013-11-02 13:06 ` Marek Polacek
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