Elias Oltmanns wrote:
>> I think the current policy is blaming gcc but I also added quite a few
>> bogus NULL initializations here and there and caught several bugs thanks
>> to those warnings. We can think about adding an additional annotation
>> with leading double underbars which indicate that certain pointer
>> arguments to functions expect (or are okay with) pointers to
>> uninitialized variables which should be able to remove many of those
>> spurious warnings (on the caller side, the compiler can ignore the
>> warning and on the callee side the compiler can check whether it's being
>> dereferenced without being written to). Does anyone know whether gcc
>> already has that type of annotation?
>
> Well, I don't know of this particular kind of annotation. However, I
> don't quite see how that would solve the reported issue.
I was thinking about the warning in sata_via.c and for such cases the
compiler doesn't have any other way of figuring out whether it's okay
or not (the sata_via case, the compiler can actually do as the callee
is in the same file but you know what I mean).
> Here, dev is a local variable and the warning is generated due to
> the line
>
> if (dev != last_failed_dev) {
>
> For this sort of thing we have:
>
> struct ata_device *uninitialized_var(dev);
Ah.. thanks.
> Or is that precisely the thing you did *not* want?
I don't know. Later versions of gcc doesn't issue warning because it
knows "if (!link)" always triggers if dev is not initialized. I don't
think we should be adding those annotations if the current gen
compiler can already figure that out as it only decreases
debuggability when something actually gets broken there.
Thanks.
--
tejun
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