Coccinelle archive on lore.kernel.org
 help / color / Atom feed
From: Julia Lawall <julia.lawall@lip6.fr>
To: "Ondřej Surý" <ondrej@sury.org>
Cc: cocci@systeme.lip6.fr
Subject: Re: [Cocci] Detecting functions with dummy return value
Date: Fri, 1 Nov 2019 20:09:21 +0100 (CET)
Message-ID: <alpine.DEB.2.21.1911012003140.2883@hadrien> (raw)
In-Reply-To: <D63C6B6A-C481-4A09-8EFF-D2760E9B85A8@sury.org>

[-- Attachment #1: Type: text/plain, Size: 1672 bytes --]



On Fri, 1 Nov 2019, Ondřej Surý wrote:

> Hi,
>
> we changed our allocator (wrapper) function to assert() instead of returning ISC_R_MEMORY.
>
> As you can imagine there’s a lot of checks down the road that needs to be cleaned up,
> so I am looking for a way to detect function that only does:
>
> isc_result_t
> foo(…) {
>
> …
> return (ISC_R_SUCCESS);
> }
>
> it could possibly be:
>
> isc_result_t
> foo(…) {
> …
> return (ISC_R_SUCCESS);
> …
> return (ISC_R_SUCCESS);
> }

This is not possible.  ... describes control-flow paths.  Nothing happens
after a return.  Your attempt above would match functions where all
control-flow paths end with return (ISC_R_SUCCESS);, even if some of those
returns are in if branches.

For the case where ISC_R_SUCCESS is in a variable, you could try:

@@
expression E;
identifier foo;
@@

isc_result_t
foo(...) {
... when any
(
-return (ISC_R_SUCCESS);
+return;
|
E = ISC_R_SUCCESS;
...
(
-return (E);
+return;
|
return (ISC_R_SUCCESS);
)
}

julia


>
> Looking at badcheck.cocci, it looks like I just need a block that would „match“ such functions,
> but I can’t find a solid example on how to write a patch that would express:
>
> Mark functions that just return ISC_R_SUCCESS and nothing else:
>
> Something like this:
>
> @match_rule@
> expression E;
> @@
>
> <+... when != E != ISC_R_SUCCESS;
> return (E);
> ...+>
>
> @depends on match_rule@
> @@
>
> - return(...);
> + return;
>
> But that doesn’t work for me, it matches all return()s.
>
> Thanks,
> Ondrej
> _______________________________________________
> Cocci mailing list
> Cocci@systeme.lip6.fr
> https://systeme.lip6.fr/mailman/listinfo/cocci
>

[-- Attachment #2: Type: text/plain, Size: 136 bytes --]

_______________________________________________
Cocci mailing list
Cocci@systeme.lip6.fr
https://systeme.lip6.fr/mailman/listinfo/cocci

  reply index

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-01 14:52 Ondřej Surý
2019-11-01 19:09 ` Julia Lawall [this message]
2019-11-01 19:22   ` Ondřej Surý
2019-11-02  6:40     ` Julia Lawall

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=alpine.DEB.2.21.1911012003140.2883@hadrien \
    --to=julia.lawall@lip6.fr \
    --cc=cocci@systeme.lip6.fr \
    --cc=ondrej@sury.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Coccinelle archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/cocci/0 cocci/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 cocci cocci/ https://lore.kernel.org/cocci \
		cocci@systeme.lip6.fr
	public-inbox-index cocci

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/fr.lip6.systeme.cocci


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git