[cfe-dev] Dead stores of NULLs

[Ted Kremenek]

On Jun 19, 2008, at 5:40 PM, Nikita Zhuk wrote:

> First I would like to express my appreciation for the great static
> analyzer, which is already producing useful results. I've been able to
> find several memory leaks and some dead stores.

That's wonderful to hear!

> However, I would like
> to address an issue which produces some dead store reports which are
> technically correct (they really are dead stores), but I would still
> like to ignore them.
>
> When I allocate an object (by using alloc & init* or one of the
> *Create* functions) and store it into a local variable inside some
> scope, I tend to set it to nil/NULL after the object has been
> released. This is an intentional dead store, which prevents any use of
> that released object later in the same scope.

I agree, the dead store checker is meant to find bugs, not penalize  
defensive programming.  The following patch causes dead assignments of  
null to pointers to not be treated as warnings:

   http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20080616/006188.html

checker-42 (on the clang website) includes this patch.  If you find  
cases where this fix doesn't handle all cases, please let me know.

Ted
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