On Fri, 2023-01-27 at 21:52 +0100, Julia Lawall wrote:
> 
> On Fri, 27 Jan 2023, Luca Coelho wrote:
> 
> > Hi,
> > 
> > I've been struggling with a change I want to make, so I hope someone
> > can help.
> > 
> > Basically I have something like this in the code:
> > 
> > /* regs below are bits 15:0 */
> > #define _MIPIA_HSYNC_PADDING_COUNT     (_MIPI_MMIO_BASE(dev_priv) + 0xb028)
> > #define _MIPIC_HSYNC_PADDING_COUNT     (_MIPI_MMIO_BASE(dev_priv) + 0xb828)
> > #define MIPI_HSYNC_PADDING_COUNT(port) _MMIO_MIPI(port, _MIPIA_HSYNC_PADDING_COUNT, _MIPIC_HSYNC_PADDING_COUNT)
> > 
> > As you can see, these macros assume that the calling functions have a
> > local called dev_priv, and I want to fix that.
> > 
> > So, I'm trying to find all users of macros that have this construct.
> > My problem is matching the nesting in the macros.
> > 
> > I have tried this:
> > 
> > @macros_noargs@
> > identifier m;
> > expression e =~ "dev_priv";
> > @@
> > #define m <+...e...+>
> > 
> > @nested_macros@
> > identifier macros_noargs.m;
> > identifier nm;
> > @@
> > #define nm(...) <+...m...+>
> > 
> > @@
> > identifier nested_macros.nm;
> > @@
> > -nm
> > +foo
> > 
> > (this last rule is just for testing if anything is matching, obviously)
> > 
> > But the "nested_macros" rule doesn't seem to work.  Does anyone know
> > how I can solve this?
> 
> I think that it works already.  If you add the following code to the .c
> file, then the call gets changed:
> 
> int main() {
>   MIPI_HSYNC_PADDING_COUNT(12);
> }
> 
> I think that the problem is that a rule that replaces an identifier by
> another doesn't match a macro definition.  Is that actually the precise
> thing you want to do?  Or do you want to do something with the uses of the
> macro.

This is the initial thing I want to do:

@@
identifier nested_macros.nm;
function f;
identifier dev_priv;
expression e;
@@
f(...) {
	...
-	struct drm_i915_private *dev_priv = e;
+	struct drm_i915_private *i915 = e;

	<+...nm(...)...+>
}

And it indeed works with a handcrafted file for testing (attached as
i915_cocci_test.c), but it doesn't work IRL, for instance in the
drivers/gpu/drm/i915/display/vlv_dsi.c file in the kernel (also
attached)...

I would expect there to be a match in the static void
bxt_dsi_get_pipe_config() function...


> If you want to change the definition, you can also add a rule like this:
> 
> @@
> identifier nested_macros.nm;
> identifier list is;
> expression e;
> @@
> 
> -#define nm(is) e
> +#define foo(is) e

This is not what I actually want to do, I just created the simplest
rule I could come up with to actually see the match (and replacement)
happening. 😉

--
Cheers,
Luca.