Add ARMv8 detection in CpuFeatures.

Add ARMv8 detection in CpuFeatures.

R=rodolph.perfetta@arm.com, ulan@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=24949

[sigurds, 2014-10-28 11:24:52]

sigurds@chromium.org changed reviewers:
+ rodolph.perfetta@arm.com

[sigurds, 2014-10-28 11:24:52]

PTAL. This is the first approach to detecting ARMv8. I don't have hardware here
to validate that it actually works.

[ulan, 2014-10-28 11:33:37]

On 2014/10/28 11:24:52, sigurds wrote:
> PTAL. This is the first approach to detecting ARMv8. I don't have hardware
here
> to validate that it actually works.

I have hardware, will validate.

[ulan, 2014-10-28 12:24:14]

On 2014/10/28 11:33:37, ulan wrote:
> On 2014/10/28 11:24:52, sigurds wrote:
> > PTAL. This is the first approach to detecting ARMv8. I don't have hardware
> here
> > to validate that it actually works.
> 
> I have hardware, will validate.

I tested that it enables ARMv8 on Nexus 9 and doesn't enable on Nexus 7.

LGTM, but please wait for Rodolph's review.

[Rodolph Perfetta (ARM), 2014-10-28 15:08:05]

lgtm

[sigurds, 2014-10-28 15:22:33]

Committed patchset #1 (id:1) manually as 24949 (presubmit successful).