Time to enable partial relro

[Konstantin Belousov]

On Thu, Aug 25, 2016 at 05:50:31PM -0500, Pedro Giffuni wrote:
> Hello;
> 
> GNU RELRO support was committed in r230784 (2012-01-30) but we never 
> enabled it by default.
> 
> There was some discussion about it on
> https://reviews.freebsd.org/D3001
> 
> By now, all Linux distributions, NetBSD and DragonFly support it and
> it is the default for most systems in binutils 2.27.
> 
> This doesn't affect performance, I ran it through an exp-run last
> year, no other OS has had issues etc ... seems safe and can be
> disabled if needed when linking.
Exp-run does not test anything interesting about relro. If all testing
that was done is basically just an exp-run, then there was no useful
runtime testing done.

> 
> I think it's time to enable it be default in our base binutils. If
> there are no objections, I will just commit the attached patch over
> the weekend.

There are objections, the change must be runtime tested on large and
representative set of real-world applications before turning the knob.