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

[Pedro Alves <palves at redhat dot com>]

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,
Pedro Alves