[LLVMdev] Is the llvm ARM support big endian elf/obj output?

[gamma_chen]

The llvm ARM backend is little endian elf output as my examination as below. Is it support bid endian by other llc options as below? llc  -filetype=obj -march=arm // little endian llc  -filetype=obj -march=? or -otheroption=? // to output big endian Jonathan

[Anton Korobeynikov]

Hello

There is not support for big endian ARM at all.

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

[陳韋任 (Wei-Ren Chen)]

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

[Tim Northover]

> 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.

[Anton Korobeynikov]

>> 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

[gamma_chen]

All, Thank you! I just want to know if it support big endian like Mips without modify/add source code at this point, since I am new in ARM backend. Jonathan --- 13/4/23 (二)，Anton Korobeynikov <an...@korobeynikov.info> 寫道： 寄件者: Anton Korobeynikov <an...@korobeynikov.info> 主旨: Re: [LLVMdev] Is the llvm ARM support big endian elf/obj output? 收件者: "gamma_chen" <gamma...@yahoo.com.tw> 副本: "LLVM Developers Mailing List" <llv...@cs.uiuc.edu> 日期: 2013年4月23日,二,下午2:29