Re: [3/3] Coccinelle: pci_free_consistent: Extend when constraints for two SmPL ellipses

[Markus Elfring <Markus.Elfring@web.de>]

Am 15.05.19 um 12:19 schrieb Julia Lawall:
>
>
> On Wed, 15 May 2019, Markus Elfring wrote:
>
>>>>> On the other hand, I do care about causing false negatives.
>>>>
>>>> Do you find the missing warning after the addition of such an exclusion
>>>> specification interesting?
>>>
>>> I already suggested how to improve the code.
>>
>> I find that the idea “e2->fld” needs further clarification.
>> Such a SmPL specification will be resolved also to an expression,
>> won't it?
>
> Saving in a local variable doesn't impact the need to free the object.

I suggest to reconsider this view.

Would we like to introduce additional case distinctions for the handling
of reassignments to local variables (as shown in Wen's test case)?


> A field is the most obvious case where the object may not need freeing.

A corresponding resource release should probably be performed by
an other function then.


> But there are many expressions that e2->fld will not match.

Data structure members can eventually belong also to a local variable.
Would they become relevant for further SmPL exclusion specifications?

Regards,
Markus