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From: David Malcolm <dmalcolm@redhat.com>
To: Eric Feng <ef2648@columbia.edu>
Cc: gcc@gcc.gnu.org, gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] analyzer: implement reference count checking for CPython plugin [PR107646]
Date: Tue, 29 Aug 2023 17:14:17 -0400	[thread overview]
Message-ID: <b7caf31bb8ab5a277e454d3c5ca46e779ed6ebed.camel@redhat.com> (raw)
In-Reply-To: <20230829172818.3264-1-ef2648@columbia.edu>

On Tue, 2023-08-29 at 13:28 -0400, Eric Feng wrote:
> Additionally, by using the old model and the pointer per your
> suggestion,
> we are able to find the representative tree and emit a more accurate
> diagnostic!
> 
> rc3.c:23:10: warning: expected ‘item’ to have reference count: ‘1’
> but ob_refcnt field is: ‘2’
>    23 |   return list;
>       |          ^~~~
>   ‘create_py_object’: events 1-4
>     |
>     |    4 |   PyObject* item = PyLong_FromLong(3);
>     |      |                    ^~~~~~~~~~~~~~~~~~
>     |      |                    |
>     |      |                    (1) when ‘PyLong_FromLong’ succeeds
>     |    5 |   PyObject* list = PyList_New(1);
>     |      |                    ~~~~~~~~~~~~~
>     |      |                    |
>     |      |                    (2) when ‘PyList_New’ succeeds
>     |......
>     |   14 |   PyList_Append(list, item);
>     |      |   ~~~~~~~~~~~~~~~~~~~~~~~~~
>     |      |   |
>     |      |   (3) when ‘PyList_Append’ succeeds, moving buffer
>     |......
>     |   23 |   return list;
>     |      |          ~~~~
>     |      |          |
>     |      |          (4) here
>     |

Excellent, that's a big improvement.

> 
> If a representative tree is not found, I decided we should just bail
> out
> of emitting a diagnostic for now, to avoid confusing the user on what
> the problem is.

Fair enough.

> 
> I've attached the patch for this (on top of the previous one) below.
> If
> it also looks good, I can merge it with the last patch and push it in
> at
> the same time.

I don't mind either way, but please can you update the tests so that we
have some automated test coverage that the correct name is being
printed in the warning.

Thanks
Dave


  reply	other threads:[~2023-08-29 21:14 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <c720fc39d86cb3ae8041fe5c86dad34d71466cec.camel@redhat.com>
2023-08-29  4:31 ` Eric Feng
2023-08-29  4:35   ` Eric Feng
2023-08-29 17:28     ` Eric Feng
2023-08-29 21:14       ` David Malcolm [this message]
2023-08-30 22:15         ` Eric Feng
2023-08-31 17:01           ` David Malcolm
2023-08-29 21:08   ` David Malcolm
2023-09-01  2:49   ` Hans-Peter Nilsson
2023-09-01 14:51     ` David Malcolm
2023-09-01 21:07       ` Eric Feng

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