Re: [PATCH,V4 10/14] gas: synthesize CFI for hand-written asm

[Indu Bhagat <indu.bhagat@oracle.com>]

On 1/8/24 00:16, Jan Beulich wrote:
> On 08.01.2024 01:46, Indu Bhagat wrote:
>> Hi Jan, Nick,
>>
>> I am working on addressing the review comments in V4 and will continue
>> that review in a separate thread.
>>
>> Meanwhile...
>>
>> On 1/5/24 05:58, Jan Beulich wrote:
>>>> +      dwarf_reg = ginsn_dw2_regnum (temp);
>>>> +    }
>>>> +
>>>> +  gas_assert (dwarf_reg != Dw2Inval); /* Needs to be addressed.  */
>>> Without actually addressing this (and possible similar cases elsewhere), I
>>> don't think this can go in as other than experimental code (which the
>>> NEWS entry then should state, and where there then should be a plan for an
>>> easy approach of probing gas for no-longer-experimental SCFI support).
>>
>> ... in this specific case, the /* Needs to be addressed.  */ comment is
>> somewhat stale and may have lead the impression that this is an
>> unhandled case (EIP is the pending unhandled case, I will deal with it
>> in V5).
>>
>> Moving forward, I would like to get consensus on whats the way forward
>> for SCFI series, especially whether there is agreement on releasing what
>> will be the V5 with binutils 2.42.
>>
>> My take on "SCFI should go as experimental code" : my priority is to get
>> this option to users and to continue development of SCFI incrementally
>> with the help/reviews from community.  If the reviewers/maintainers
>> think, offering this first as --scfi=experimental, which later is
>> established as --scfi=all, in a future release is the best way to move
>> forward, I can make the necessary changes now.
> 
> I'd be okay with this as a plan. Before fully supported, I'd actually hope
> to see at least one other architecture to also use this machinery. Yet
> maybe that's asking for too much ...
> 

Thanks Jan.

BTW, I have implementation for SCFI for aarch64 in a personal branch. 
FWIW, the current state of ginsn/scfi  machinery (as posted in V4) 
"works" on aarch64. That said, the aarch64 implementation is minimally 
tested at this time and needs more work.

I hope to upstream that at some point.

Indu