[PATCH] Driver: add target definition for Windows on ARM

[Saleem Abdulrasool]

================
Comment at: lib/Basic/Targets.cpp:4428
@@ +4427,3 @@
+    // 31: VFPv3 40: VFPv4
+    Builder.defineMacro("_M_ARM_FP", "31");
+  }
----------------
Renato Golin wrote:
> You default to cortex-a9 and VFPv4 at the same time, but A9 is VFPv3. You should either default to v3 or require A15/A7+.
I might be mistaken (and if I am some how defaulting to VFPv4, then that is a bug).  I compacted the comment above, it really is saying:

31 = VFPv3
40 = VFPv4

I did miss a FIXME to indicate that the value should be based upon the actual value of the VFP that is being specified.

================
Comment at: lib/Basic/Targets.cpp:3719
@@ +3718,3 @@
+      T.getArchName().substr(Offset).getAsInteger(10, Version);
+      assert(Version >= 7);
+      return true;
----------------
Renato Golin wrote:
> Isn't an assert a bit too drastic? Maybe we should catch this somewhere else with an error message?
It is drastic, but AFAIK, WoA requires ARMv7 or greater.  Reporting an error message is certainly much nicer.


http://llvm-reviews.chandlerc.com/D3241