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From: Thomas Adam <thomas@xteddy.org>
To: cocci@systeme.lip6.fr
Subject: [Cocci] Using cocci to mangle function arguments
Date: Sun, 17 May 2020 01:16:46 +0100
Message-ID: <20200517001646.gtobyv6jea5bugfr@debian> (raw)

Hi all,

I have a situation where I'm trying to use Coccinelle to both rename one
function to another, and at the same time modify the number of arguments.

I have a function called:

    func_old(ERR, "func_name", "%s message", charstring);

Which is therefore variadic.  In terms of argument ordering func_old() takes:

  1.  log-level type
  2.  the calling function
  3.  A variadic string

I'm wanting to replace func_old() with func_new() such that it looks like
this:

    func_new("%s: %s message", __func__, charstring);

Hence, func_new() reduces the number of arguments to just one -- a format
string, and variadic arguments.

My question is how would I go about trying to get coccinelle to help me
translate this?  Is this even possible?  I have tried:

@@
expression O1, O2, O3
@@

- func_old(O1, O2, O3, ...);

But I don't know how to convert what would be O2 to '__func__'.  When calling
func_new(), there is no explicit O2 parameter from func_old(), it should be
part of the format string, hence:

+ func_new("%s: ...", __func__, O3);

I suspect I might be stretching coccinelle's abilities in trying to craft new
parameters, but I thought I'd ask.

Apologies if this is convoluted.  If I can help answer any additional
questions, or if something's not clear, let me know.

TIA!

Thomas
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Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-17  0:16 Thomas Adam [this message]
2020-05-17  8:07 ` Julia Lawall

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