[cfe-dev] Proposal: -Wshadow-field flag

[Reid Kleckner]

I think this would be a great addition! In general, -Wshadow fires in a lot
of situations, and I think having more granularity here is helpful for
users.

On Sat, Apr 18, 2015 at 11:05 AM, Ehsan Akhgari <ehsan.akhgari at gmail.com>
wrote:

> Hi everyone,
>
> I would like to propose adding a -Wshadow-field to clang.  This flag would
> emit a warning if a derived class declares a member with the same name as
> one in one of the base classes, regardless of visibility.
>
> Here is the rationale: In the Mozilla code base, there are fields that are
> often declared with the same name in thousands of classes, either by
> convention or through macros.  One concrete example is mRefCnt, which is
> the variable holding the object's reference count.  Every once in a while,
> we find bugs that are caused by the derived class inadvertently shadowing
> the base member, and therefore code in the derived class and its
> descendants in the hierarchy will access the wrong variable.  In the case
> of mRefCnt, for example, these bugs are security sensitive since this
> typically causes the reference count of the object to get out of balance,
> causing use-after-free issues.  One can conceive of other similar problems
> with other fields as well.
>
> I was going to implement this warning in the clang plugin that we use for
> static analysis of our code base, but realized that this may probably be
> useful for other projects as well.  Is there any interest in this feature?
> If yes, I would be happy to submit a patch.
>
> Cheers,
> --
> Ehsan
>
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20150420/759c822f/attachment.html>