On Thu, Jun 21, 2012 at 6:45 PM, Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
>> I wonder if I should make sparse warn about any casts to/from enums.
>> They tend to always be wrong.
>
> I think it would be worth trying, see how much fallout there is. Also
> casts from "enum a" to "enum b". We've had a few of those,
> unintentionally.
Ugh. We have this all over. Well, at least in multiple places.
Like <linux/personality.h>, which does things like
PER_LINUX_32BIT = 0x0000 | ADDR_LIMIT_32BIT,
where PER_LINUX_32BIT is one enum, and ADDR_LIMIT_32BIT is a different one.
And things like
WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT,
in <linux/workqueue.h> is similar.
Sure, my quick warning generator gives lots of extraneous warnings,
and it complains about the above kind of "mixing enum with int"
behavior, but the above is a very real example of casting an enum to
an integer. And we *want* it to happen in the above cases.
I'll see what it looks like if I only warn about casting *to* an enum.
Linus
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