Make ARM64 detection consistent in chromium.

Make ARM64 detection consistent in chromium.

This is to uniform ARM64 detection code in chromium.
Use only __aarch64__ and don't look for __arm64__ at all.


BUG=chromium:354405, chromium:358092

[primiano]

Mark could you please take a look.
I am trying to make the __arm64__ vs __aarch64__ situation in chromium a bit
more consistent.
There should be no change for Mac since clang defines both.
Thanks.

[Mark Mentovai]

arm64 is more of a “says what it means” than aarch64 for most people. Why did
you choose aarch64? Which compilers define these macros?

[primiano]

On 2014/04/01 14:09:42, Mark Mentovai wrote:
> arm64 is more of a “says what it means” than aarch64 for most people. Why did
> you choose aarch64? Which compilers define these macros?

GCC defines only __aarch64__
Older versions of clang define only  __aarch64__
The XCode 5 and the newer (last week) upstream clang define both

If there aren't strong objections, I'd like all the code in the chromium
codebase to look the same (makes searches easier).
I agree that __arm64__ would have been much nicer, but nope, we can't due to
GCC.

[Mark Mentovai]

LGTM. I agree that consistency wins, I just wanted to know why you chose the
uglier name to standardize on.

[primiano]

On 2014/04/01 14:33:01, Mark Mentovai wrote:
> LGTM. I agree that consistency wins, I just wanted to know why you chose the
> uglier name to standardize on.

It could have been worse, it could have been __AARCH64EL__ ;-)

[primiano]

BTW, how am I supposed to land this?
Can you do that for me? Or should I be added somehow to the code.google.com
project members?

[Mark Mentovai]

+blundell too as an FYI, since he added ARM64 iOS support.

Committed Breakpad r1293. Let me know if you plan on making more changes to
Breakpad, and I’ll give you write access.