Re: [Cocci] Reducing source code around return statements with SmPL?

From: Markus Elfring <Markus.Elfring@web.de>
To: Julia Lawall <julia.lawall@lip6.fr>
Cc: Coccinelle <cocci@systeme.lip6.fr>
Subject: Re: [Cocci] Reducing source code around return statements with SmPL?
Date: Tue, 24 Sep 2019 21:24:50 +0200	[thread overview]
Message-ID: <f41b8e72-9a79-e65a-a652-8a257d5fac71@web.de> (raw)
In-Reply-To: <alpine.DEB.2.21.1909241729310.2282@hadrien>

> rc comes from check1 so it should be inherited from check1.

I stumble on understanding difficulties for the currently supported
software functionality.

@check1@
expression x;
identifier rc;
local idexpression lrc;
position p;
@@
 lrc@rc = x@p;
 return lrc;

@check2@
identifier check1.rc;
position p;
type t;
@@
 t rc@p;
 ... when != rc

@script:python to_do1@
p << check1.p;
@@
coccilib.org.print_todo(p[0],
                        "WARNING: An expression was assigned to a local variable before it will be returned by the subsequent statement.")

@script:python to_do2@
p << check2.p;
v << check1.rc;
@@
coccilib.org.print_todo(p[0],
                        "INFO: May the local variable \""
                        + v
                        + "\" be deleted?")

elfring@Sonne:~/Projekte/Linux/next-patched> spatch ~/Projekte/Coccinelle/janitor/move_code_to_return2.cocci arch/arm64/kernel/ptrace.c

Three source code places are pointed out by the SmPL rule “to_do1”
as it would be expected.
Unfortunately, I miss the message “INFO: May the local variable "err" be deleted?”
for the function “ptrace_hbp_set_addr” according to the SmPL rule “to_do2”.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/kernel/ptrace.c?id=08f103b9a9502974109fab47ea35ca8542c4e57a#n451

Which adjustments will become relevant here?

Regards,
Markus
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