Re: [Cocci] Can the current function name be passed to a Python snippet?

[Julia Lawall <julia.lawall@lip6.fr>]

On Tue, 4 Dec 2018, Timur Tabi wrote:

> On Tue, Dec 4, 2018 at 2:25 PM Julia Lawall <julia.lawall@lip6.fr> wrote:
> >
> >
> >
> > On Tue, 4 Dec 2018, Timur Tabi wrote:
> >
> > > On Thu, Nov 15, 2018 at 3:29 PM Julia Lawall <julia.lawall@lip6.fr> wrote:
> > >
> > > > The name of the current function at a given match is available in a
> > > > position variable bound as part of that match.  A position variable should
> > > > have a current_element field.
> > >
> > > Unfortunately, I don't understand what you're saying.  I see some
> > > examples referencing the "position" in a Python script, but they don't
> > > make any sense to me, e.g.
> > >
> > > http://coccinelle.lip6.fr/docs/main_grammar016.html#sec27
> > >
> > > The example shows:
> > >
> > > @ r exists @
> > > local idexpression struct device_node *n;
> > > position p1, p2;
> > > statement S1,S2;
> > > expression E,E1;
> > >
> > > I assume when you say "position parameter", you're talking about the
> > > "position p1, p2;" above.  If so, I'm completely confused.
> >
> > In the example, p1 will store the position of n.  In the python rule, you
> > can then access p1[0].current_element to get the name of the function in
> > which n occurs.
>
> What do you mean by "position of n"?

The code that n matches is in some file, within some function, at some
line number, and at some column offset.  All of that information is
collected in p1.

>
> I managed to figure it out without using positional parameters.  It
> almost works in that it only does the replacement once:
>
> // Look for NV_PRINTF2 calls that have the function name in the string
> @r4 depends on rules@
> identifier func;
> expression x;
> constant char[] c;
> @@
> func(...) {
> ...
> NV_PRINTF2(x, c, ...)
> ...
> }

This can work, but as written it requires exactly one call to NV_PRINTF2
on every control-flow path through the function.  It also has to trace
through the entire function, which will be expensive.

> // Get rid of the function name at the beginning of the string
> @script:python s4@
> c << r4.c;
> c2;
> f << r4.func;
> @@
> import re
> coccinelle.c2 = re.sub('"%s[: ]*' % f, '"', c, 1)
>
> @depends on rules@
> expression x;
> constant char[] r4.c;
> identifier s4.c2;
> @@
> NV_PRINTF2(x,
> -c
> +c2
> ,...);
>
> Based on what I've read, I need to add < > in order for spatch to run
> the rule multiple times within a function.  But if I change r4 to
> this:
>
> @r4 depends on rules@
> identifier func;
> expression x;
> constant char[] c;
> @@
> func(...) {
> <...
> NV_PRINTF2(x, c, ...)
> ...>
> }
>
> It doesn't work at all.

What do you mean by doesn't work at all?

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