Re: [PATCH 1/5] Poison non-POD memset & non-trivially-copyable memcpy/memmove

[Simon Marchi <simon dot marchi at polymtl dot ca>]

On 2017-05-17 07:35, Pedro Alves wrote:
> On 04/30/2017 02:51 AM, Simon Marchi wrote:
>
> > I think it would be a good guideline to use new/delete for types that
> > have some C++-related stuff in them, even if it's not technically
> > necessary.
> >
> > Note that this won't be bulletproof also because at many places xfree 
> > is
> > used on a void pointer, so we don't know what we're really free'ing.  
> > In
> > some other cases, objects are freed using a pointer to their "C base
> > class".
>
> Yeah.  Still, better than nothing.
>
> BTW, GCC ran into similar issues almost at the same time
> we started discussing this, and I've been discussing
> with the GCC folks about a new GCC warning that flags invalid
> memcpy/memset misuses.  Martin Sebor has been working on a patch
> and it's getting close to be merged, AFAICT.
>
> See:
>  https://gcc.gnu.org/ml/gcc-patches/2017-04/msg01527.html
> First version of the GCC patch here:
>  https://gcc.gnu.org/ml/gcc-patches/2017-04/msg01571.html
> Discussion crossed month boundary here:
>  https://gcc.gnu.org/ml/gcc-patches/2017-05/msg00925.html
> Latest patch is here:
>  https://gcc.gnu.org/ml/gcc-patches/2017-05/msg00976.html
>
> I won't be a full replacement since we'll still want our
> poisoning for other functions (xmalloc, xfree, etc.).  And
> then there's current/older gccs.  But still, pretty neat, IMO.

Thanks for the info!

I have a branch in progress about poisoning XNEW and friends:
https://github.com/simark/binutils-gdb/commits/poison-xnew

I won't have time to look at it until at least next week, if anybody 
wants to pick it up, they are free to do so.

Simon