[LLVMdev] ARM thumb-2 instruction used for non-thumb2 CPUs

Damjan Marion damjan.marion at gmail.com
Wed Jun 22 16:02:00 PDT 2011

On Jun 23, 2011, at 12:01 AM, Jim Grosbach wrote:

> On Jun 22, 2011, at 2:08 PM, Renato Golin wrote:
>> On 22 June 2011 19:18, Anton Korobeynikov <anton at korobeynikov.info> wrote:
>>> Unfortunately, you have to live with this. Until recently binutils
>>> were quite buggy wrt thumb2 code, so, most probably you will need new
>>> binutils in any case.
>> Hi Anton,
>> It's not so simple. GPL3 can be quite a nuisance to change and even to
>> use. This is why LLVM is becoming to popular for ARM... ;)
>> Jim, how much work would you reckon it'll take to have a working assembler?
> You mean to patch the old binutils to support this old instruction? Very easy, I'd expect (well, as easy as anything ever is in binutils).
> To get -integrated-as working so that we don't need to go through the assembler at all should be mostly a matter of bug fixing, modulo inline assembly support. For non-trivial inline assembly, and to get a system assembler replacement based on the MC assembler, it'll be a bigger task. The ARM asm parser is currently in need of some tender loving care. That's coming soon, but it's a non-trivial task.
> For -integrated-as, I would suggest giving it a try. I'm not completely sure how complete the support is for ELF, but I think it's in somewhat OK shape, at least. Worth trying. That would neatly avoid the problem if it works. If it doesn't, we should fix the bugs so it does. ;)

I tried with FreeBSD kernel. Outcome is 2 different crashes. Output is here:


I can provide more details if needed.


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