From mboxrd@z Thu Jan  1 00:00:00 1970
From: joel@joelfernandes.org (Joel Fernandes)
Date: Thu, 11 Oct 2018 09:49:34 -0700
Subject: [Cocci] Searching for parameter usages of pte_alloc()
In-Reply-To: <alpine.DEB.2.20.1810111833410.3392@hadrien>
References: <20181010211125.GA128537@joelaf.mtv.corp.google.com>
 <93da55ff-c807-6587-7ef3-3d2af820117d@users.sourceforge.net>
 <20181011154346.GA186033@joelaf.mtv.corp.google.com>
 <alpine.DEB.2.20.1810111746210.3392@hadrien>
 <20181011162840.GA199386@joelaf.mtv.corp.google.com>
 <alpine.DEB.2.20.1810111833410.3392@hadrien>
Message-ID: <20181011164934.GA213196@joelaf.mtv.corp.google.com>
To: cocci@systeme.lip6.fr
List-Id: cocci@systeme.lip6.fr

On Thu, Oct 11, 2018 at 06:40:22PM +0200, Julia Lawall wrote:
> > Sure, so if I have code like this:
> > #define pte_alloc_one(mm, vmaddr) ((pte_t *) page_table_alloc(mm))
> >
> > I want to have a rule that does:
> > - #define pte_alloc_one(mm, vmaddr) ((pte_t *) page_table_alloc(mm))
> > + #define pte_alloc_one(mm) ((pte_t *) page_table_alloc(mm))
> >
> > So far everything I tried only works for functions so I was wondering how one
> > do this with macros.
> 
> Maybe
> 
> @r@
> position p;
> identifier i,a,b;
> @@
> 
> #define i(a,b)@p <+...b...+>
> 
> @@
> position p != r.p;
> identifier i,a,b;
> expresssion e;
> @@
> 
> - #define i(a,b)@p e
> + #define i(a) e
> 
> The rule r finds #defines that refer to the second argument, and records
> their position in p, while the second rule finds all other #defines with
> two arguments.

Thanks a lot, I will try these.

> Of course, you would want to use a regular expression for the macro name,
> or do something to avoid changing all two argument macros.
> 
> Macros are often defined in header files, so you may want to use the
> command line options --no-includes --include-headers.  --no-includes means
> ignore header files when they are included into .c files and
> --include-headers means treat both .c an .h files.  Otherwise, you only get
> .c files.

 I am using --include-headers. I didn't get the --no-includes use with
 --include-headers though.

What happens if I don't pass --no-includes?  Do the header files included
from C files also get matched then? Then in that case I shouldn't need to
pass anything (neither --include-headers nor --no-includes) and all included
headers from C files should also be matched/parsed/patched - since every
header should atleast be included *somewhere* otherwise its existinence is
pointless. Could you help me understand this better? Thanks a lot!

 - Joel