Implement link-time optimization safe explicit_bzero()?

[Sebastian Huber]

----- Manuel López-Ibáñez <manuel.lopez-ibanez@manchester.ac.uk> schrieb:
> On 11/02/16 14:29, Sebastian Huber wrote:
> > Hello,
> >
> > how can I implement a link-time optimization safe explicit_bzero() that works with a fully LTO enabled statically linked program?
> 
> My understanding by reading this thread 
> (https://sourceware.org/ml/libc-alpha/2016-01/msg00208.html) is that this is 
> not possible at the moment because of lacking compiler support. See also 
> https://sourceware.org/ml/libc-alpha/2015-11/msg00467.html and follow-ups.

I still think optimizing compilers are a good thing.

> 
> If I were to tackle this problem, I would try first to implement a 
> __builtin_explicit_bzero() directly in GCC such that GCC will know exactly how 
> to handle it. This would be faster, safer and more portable than any trick you 
> may get working now (since LTO keeps improving), and it will provide the basis 
> for a gnu libc implementation.

Ok, since I am not a compiler expert, I need an example for this.  My first try was to search for the memset_s() builtin. However, this doesn't seem to exist.  Is memset_s() supported at all by GCC currently?

[...]
> Of course, there is the question of whether explicit_bzero() or similar 
> functions are a solution at all to any problem 
> (https://sourceware.org/ml/libc-alpha/2016-01/msg00208.html)

Would a builtin not fix this issue? I am not sure if I understood this post at all.

-- 
Sebastian Huber, embedded brains GmbH

Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone   : +49 89 189 47 41-16
Fax     : +49 89 189 47 41-09
E-Mail  : sebastian.huber at embedded-brains.de
PGP     : Public key available on request.

Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.