Avoid two SSP ABI's for AArch64.

[Carlos O'Donell]

On 12/06/2013 09:26 AM, Marcus Shawcroft wrote:
> The first sequence is a very common A64 idiom,  while the latter
> sequence is much less common.  From discussion with various
> u-architects I am led to believe that given a range of different
> AArch64 u-architectures each with a unique set of design trade offs,
> the MRS implementation is a best going to have equivalent performance
> to the ADRP, but will be most likely to have the largest variation in
> implementation performance.
> 
> My view therefore is that we should run with the __stack_chk_guard
> global data mechanism.

I appreciate you reaching out to the contacts you have and for making
a decision on this.

Can I get you to confirm that for AArch64 we're going to use the
global data access mechanism for the stack guard value used by 
the stack smashing code code?

This means no ABI change for LLVM or GCC.

Cheers,
Carlos.