[PATCH] [PATCH] Add a subtarget feature "v8" to ARM

[Tim Northover]

Hi Joey,

To me it looks like there are a couple of patches here:
+ Support v8
+ Stop emitting v7 attributes when the compiler has really selected
something like v4

The latter change appears to have no tests.

On the details:

+      if (Len >= Idx+2 && TT[Idx+1] == 'm')
+        isThumb = true;

Are you really sure you want to support v8m at this stage, let alone
in such a half-hearted way? I'd have wanted to get the v8a features
correct first, since if nothing else cortex-a53 is an A-class core.

It would also be good to see a test for "thumbv8" since that's likely
to be used quite a bit.

Other than that, it looks good.

Cheers.

Tim.