[PATCH] ARM IAS: improve .eabi_attribute handling

[Logan Chien]

================
Comment at: lib/Target/ARM/MCTargetDesc/ARMBuildAttrs.cpp:63
@@ +62,3 @@
+  { ARMBuildAttrs::Virtualization_use, "Tag_Virtualization_use" },
+  { ARMBuildAttrs::MPextension_use_old, "Tag_MPextension_use_old" },
+
----------------
Saleem Abdulrasool wrote:
> Logan Chien wrote:
> > IMO, we should not parse Tag_MPextension_use_old for two reasons: (1) This value is deprecated (2) There is no existing usage of this tag name.
> I can drop it from the table, but that does not prevent someone from using the numeric value.  Why should we drop the textual representation in that case?
> 
> Im not really opposed to removing it, I would just like to understand why dropping it partially is better than just permitting the compatibility.
IIRC, the tag name "Tag_MPextension_use_old" is not mentioned in the ARM document.  ARMBuildAttrs.h added this enumeration only for internal use.  There wasn't be any legacy code using this tag name.  I feel strange to define a new tag name for a deprecated old value.  Besides, GNU as does not support this tag name.


http://llvm-reviews.chandlerc.com/D2484