[cfe-commits] PATCH: Enhance array bounds checking

[Eli Friedman]

On Thu, Jul 14, 2011 at 10:40 AM, David Blaikie <dblaikie at gmail.com> wrote:
>> Do we really want this to be a warning?
>
> 5.7/5 allows for well defined behavior when a pointer points to one past the
> end of an array, but is not dereferenced (I haven't fully comprehended which
> cases are allowed & denied by this change, though - so I'm just stating this
> for completeness) & this is often used for iterator pair semantics.
>
>>
>> There are plenty of examples where an out-of-bounds pointer is computed
>> for legit reasons.  As long as that address is not dereferenced, there isn't
>> necessarily a problem.  I'm fearful this may generate a fair amount of noise
>> on codebases that do elaborate tricks with pointer offsets.  Indeed this
>> very example doesn't actually exhibit a "bug".
>
> Indeed even in the examples given, "Foo" + 5, makes a fair amount of sense -

Your math is off-by-one; Foo+4 is legal, Foo+5 is not.

-Eli