Is there a way to build a cross reference with kernel file

[Jeff Haran]

> -----Original Message-----
> From: Javier Martinez Canillas [mailto:martinez.javier at gmail.com]
> Sent: Friday, December 16, 2011 6:04 PM
> To: Jeff Haran
> Cc: Alexandre Courbot; Jimmy Pan; Kernelnewbies at kernelnewbies.org
> Subject: Re: Is there a way to build a cross reference with kernel file
> 
> On Sat, Dec 17, 2011 at 1:58 AM, Jeff Haran <jharan at bytemobile.com>
> wrote:
> >> -----Original Message-----
> >> From: kernelnewbies-bounces at kernelnewbies.org
> [mailto:kernelnewbies-
> >> bounces at kernelnewbies.org] On Behalf Of Alexandre Courbot
> >> Sent: Monday, October 24, 2011 7:05 PM
> >> To: Jimmy Pan
> >> Cc: Kernelnewbies at kernelnewbies.org
> >> Subject: Re: Is there a way to build a cross reference with kernel
> > file
> >>
> >> On Tue, Oct 25, 2011 at 12:00 AM, Jimmy Pan <dspjm1 at gmail.com>
> wrote:
> >> > It seems we can use ctags, while, I don't really know how to
> > implement it.
> >> > I don't want to use the online cross reference every time...
> >>
> >> I personally use KDevelop to navigate the kernel. It's not perfect yet
> >> and a little bit tricky to configure correctly, but it's still pretty
> >> efficient and I work on improving it. I wrote about it recently:
> >> http://www.gnurou.org/code/kdevelop-kernel
> >>
> >> CTags is also known to work well, actually there is even a 'make tags'
> >> target in the kernel's Makefile.
> >>
> >> Hope this helps,
> >> Alex.
> >
...
> > Has anybody found a tool the solves this kind of problem well?
> > Specifically, given a struct foo containing a field named bar, show me
> > all of the code that references the bar field of struct foos but not the
> > bar fields of other structures nor instances of variables that are
> > themselves named bar.
> >
> > I realize that with things like arbitrary type casting and the C
> > pre-processor, doing this kind of thing with 100% accuracy could be
> > quite difficult. But even if it was only partially successful at
> > eliminating the false positives that come with tools like cscope, it
> > could save a lot of time.
> >
> 
> Well you can always rely on conventions. For the sk_buff example,
> generally the kernel uses sk_buff pointers and the variable name is
> almost always skb. So git grep skb->cb is a good approach to this.

Problem is one can't count on these conventions being followed. There are pointers to struct sk_buffs that aren't named skb (for example, struct sk_buff *skbuff and struct sk_buff *skb2 appear in several places) so by assuming they are all named skb will mean you miss some that might be important.

... 

> Again, ETAGS and tools like that are good for pointing where a symbol
> is defined, but its usage is a little more trickier. Like you said the
> kernel uses _lots_ of functions pointers so I don't think that a tool
> that shows me every place a given function is called will be easier
> (if possible) to implement.

Yes, that's another problem. And agreed, something like this would likely be difficult to put together given the way C works.

> Hope it helps,
> 
> --
> Javier Martínez Canillas
> (+34) 682 39 81 69
> Barcelona, Spain

Well, it helps in the sense that I think it answers my question. No such tool seems to exist.

Thanks,

Jeff Haran