llvm dev - Apr 2013 - [LLVMdev] Is the llvm ARM support big endian elf/obj output?

On Tue, Apr 23, 2013 at 10:29:32AM +0400, Anton Korobeynikov
wrote:
> Hello
> 
> There is not support for big endian ARM at all.
  I guess he need to change the data layout string in
ARMTargetMachine::ARMTargetMachine (ARMTargetMachine.cpp)
from "e" to "E" to get big endian output?

Regards,
chenwj

-- 
Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667
Homepage: http://people.cs.nctu.edu.tw/~chenwj

> I guess he need to change the data layout string in
> ARMTargetMachine::ARMTargetMachine (ARMTargetMachine.cpp)
> from "e" to "E" to get big endian output?
That would be a start, but I'd expect a significant number of bugs
where the backend writers have assumed ARM was little-endian
(lib/Target/Mips, which *does* support both, has many more endian
checks in the code than ARM).

Tim.

>> I guess he need to change the data layout string in
>> ARMTargetMachine::ARMTargetMachine (ARMTargetMachine.cpp)
>> from "e" to "E" to get big endian output?
>
> That would be a start, but I'd expect a significant number of bugs
> where the backend writers have assumed ARM was little-endian
> (lib/Target/Mips, which *does* support both, has many more endian
> checks in the code than ARM).
Also note that NEON stuff is "almost" little-endian. So, huge changes
will be needed here.

--
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University