From: "Martin Liška" <mliska@suse.cz>
To: Jakub Jelinek <jakub@redhat.com>
Cc: Richard Biener <richard.guenther@gmail.com>,
GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] Speed-up use-after-scope (re-writing to SSA) (version 2)
Date: Fri, 20 Jan 2017 14:27:00 -0000 [thread overview]
Message-ID: <5ca02d10-8023-63ea-1669-e5f56f08ec67@suse.cz> (raw)
In-Reply-To: <ec320375-d950-7d11-e996-6044b96dc22e@suse.cz>
On 01/20/2017 12:49 PM, Martin Liška wrote:
> Great, thanks a lot. I'm going to re-trigger asan-bootstrap with your patch.
> I'm also adding gcc/testsuite/gcc.dg/asan/use-after-scope-10.c that is a valid
> test-case for this issue.
Hi.
Unfortunately this way would not work as clobber marks content of the memory as uninitialize
is different behavior that just marking a memory can be used (and maybe already contains a value).
This shows the problem:
#include <string.h>
char cc;
char ptr[] = "sparta2";
void get(char **x)
{
*x = ptr;
}
int main()
{
char *here = &cc;
for (;;)
{
next_line:
if (here == NULL)
__builtin_abort();
get (&here);
if (strcmp (here, "sparta") == 0)
goto next_line;
else if (strcmp (here, "sparta2") == 0)
break;
}
}
With the patch, DSE would optimize out '*here = &cc;' and thus aborts. The problem is definitely
related to goto magic, where we are more defensive in placement of ASAN_MARK(UNPOISON,...).
Hope your optimization is still valid for situations w/o artificial ASAN_MARK(UNPOISON,...) placed due
to goto magic.
Do we still want to do it now, or postponing to GCC 8 would be better option?
Thanks,
Martin
next prev parent reply other threads:[~2017-01-20 14:08 UTC|newest]
Thread overview: 111+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-06 11:04 [PATCH, RFC] Introduce -fsanitize=use-after-scope Martin Liška
2016-05-06 11:08 ` [PATCH] Introduce tests for -fsanitize=use-after-scope Martin Liška
2016-05-11 12:56 ` Martin Liška
2016-05-06 11:16 ` [PATCH, RFC] Introduce -fsanitize=use-after-scope Martin Liška
2016-05-06 11:48 ` Yury Gribov
2016-05-06 12:39 ` Jakub Jelinek
2016-05-06 13:07 ` Martin Liška
2016-05-06 14:22 ` Yury Gribov
2016-05-06 14:39 ` Jakub Jelinek
2016-05-10 15:03 ` Martin Liška
2016-05-10 15:15 ` Jakub Jelinek
2016-05-06 13:17 ` Martin Liška
2016-05-06 13:25 ` Jakub Jelinek
2016-05-06 14:41 ` Martin Liška
2016-05-06 14:46 ` Jakub Jelinek
2016-05-06 12:22 ` Jakub Jelinek
2016-05-11 12:54 ` Martin Liška
2016-05-12 10:42 ` Jakub Jelinek
2016-05-12 14:12 ` Martin Liška
2016-08-12 12:42 ` Martin Liška
2016-08-18 13:36 ` Jakub Jelinek
2016-10-03 9:27 ` [PATCH, RFC] Introduce -fsanitize=use-after-scope (v2) Martin Liška
2016-10-03 9:30 ` [PATCH, 02/N] Introduce tests for -fsanitize-address-use-after-scope Martin Liška
2016-11-07 10:04 ` [PATCH, 02/N] Introduce tests for -fsanitize-address-use-after-scope (v3) Martin Liška
2016-11-07 10:09 ` Jakub Jelinek
2016-10-03 9:39 ` [PATCH, RFC] Introduce -fsanitize=use-after-scope (v2) Jakub Jelinek
2016-10-07 11:13 ` Jakub Jelinek
2016-10-12 14:08 ` Martin Liška
2016-10-21 14:26 ` Jakub Jelinek
2016-10-25 13:18 ` Martin Liška
2016-10-27 14:40 ` Martin Liška
2016-10-27 17:24 ` Jakub Jelinek
2016-11-01 14:48 ` Martin Liška
2016-11-01 14:54 ` Jakub Jelinek
2016-11-01 15:01 ` Martin Liška
2016-11-02 9:36 ` Martin Liška
2016-11-02 9:59 ` Jakub Jelinek
2016-11-02 10:09 ` Martin Liška
2016-11-02 10:11 ` Jakub Jelinek
2016-11-02 14:20 ` Marek Polacek
2016-11-02 14:27 ` Martin Liška
2016-11-02 14:35 ` Jakub Jelinek
2016-11-04 9:17 ` Martin Liška
2016-11-04 9:33 ` Jakub Jelinek
2016-11-04 10:59 ` Martin Liška
2016-11-07 10:03 ` [PATCH, RFC] Introduce -fsanitize=use-after-scope (v3) Martin Liška
2016-11-07 10:08 ` Jakub Jelinek
2016-11-08 8:58 ` Question about lambda function variables Martin Liška
2016-11-08 9:12 ` Jakub Jelinek
2016-11-08 9:35 ` Martin Liška
2016-11-07 16:07 ` Fix build of jit (was Re: [PATCH, RFC] Introduce -fsanitize=use-after-scope (v3)) David Malcolm
2016-11-07 16:17 ` Jakub Jelinek
2016-11-08 9:38 ` Martin Liška
2016-11-08 9:41 ` Jakub Jelinek
2016-11-08 12:00 ` [PATCH] use-after-scope fallout Martin Liška
2016-11-08 12:10 ` Jakub Jelinek
2016-11-08 18:05 ` David Malcolm
2016-11-01 14:54 ` [PATCH, RFC] Introduce -fsanitize=use-after-scope (v2) Martin Liška
2016-11-01 15:12 ` Jakub Jelinek
2016-11-02 9:40 ` Richard Biener
2016-11-02 9:44 ` Martin Liška
2016-11-02 9:52 ` Jakub Jelinek
2016-11-02 12:36 ` Richard Biener
2016-11-02 12:56 ` Jakub Jelinek
2016-11-02 12:59 ` Richard Biener
2016-11-02 13:06 ` Jakub Jelinek
2016-11-02 13:16 ` Richard Biener
2016-11-02 14:38 ` Martin Liška
2016-11-02 14:51 ` Jakub Jelinek
2016-11-02 15:25 ` Martin Liška
2016-11-03 13:34 ` Martin Liška
2016-11-03 13:44 ` Jakub Jelinek
2016-11-03 14:02 ` Martin Liška
2016-11-03 14:04 ` Jakub Jelinek
2016-11-03 14:18 ` Martin Liška
2016-11-16 12:25 ` [RFC][PATCH] Speed-up use-after-scope (re-writing to SSA) Martin Liška
2016-11-16 12:53 ` Martin Liška
2016-11-16 13:07 ` Jakub Jelinek
2016-11-16 16:01 ` Martin Liška
2016-11-16 16:28 ` Jakub Jelinek
2016-11-22 11:55 ` Martin Liška
2016-11-23 13:57 ` Martin Liška
2016-11-23 14:14 ` Jakub Jelinek
2016-12-01 16:30 ` Martin Liška
2016-12-02 12:29 ` Richard Biener
2016-12-08 12:51 ` Martin Liška
2016-12-13 14:16 ` Richard Biener
2016-12-20 11:34 ` [PATCH] Speed-up use-after-scope (re-writing to SSA) (version 2) Martin Liška
2016-12-21 9:19 ` Jakub Jelinek
2016-12-22 17:11 ` Martin Liška
2016-12-22 17:28 ` Jakub Jelinek
2017-01-09 14:58 ` Martin Liška
2017-01-16 14:20 ` Jakub Jelinek
2017-01-17 16:22 ` Martin Liška
2017-01-17 16:55 ` Jakub Jelinek
2017-01-18 15:37 ` Martin Liška
2017-01-19 16:43 ` Jakub Jelinek
2017-01-20 11:55 ` Martin Liška
2017-01-20 14:27 ` Martin Liška [this message]
2017-01-20 14:30 ` Jakub Jelinek
2017-01-20 14:42 ` Markus Trippelsdorf
2017-01-23 9:38 ` Martin Liška
2017-01-23 9:39 ` Jakub Jelinek
2017-01-23 12:07 ` Martin Liška
2017-01-26 9:04 ` Thomas Schwinge
2017-01-26 10:55 ` Jakub Jelinek
2017-01-26 20:45 ` Thomas Schwinge
2017-01-26 20:52 ` Jakub Jelinek
2016-11-16 16:09 ` [RFC][PATCH] Speed-up use-after-scope (re-writing to SSA) Martin Liška
2016-11-02 9:52 ` [PATCH, RFC] Introduce -fsanitize=use-after-scope (v2) Martin Liška
2016-09-03 15:23 ` [PATCH, RFC] Introduce -fsanitize=use-after-scope Jakub Jelinek
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