[LLVMdev] RFC: MachineInstr Annotations

[Chris Lattner]

On Aug 1, 2009, at 1:20 PM, Dan Gohman wrote:
>> We could also mark instructions as spills but Chris has pointed out
>> that we
>> can probably synthesize that in AsmPrinter with just a little bit of
>> work.
>> The above information can't be inferred from stack layouts or
>> anything else.
>>
>> Thoughts?
>
> I'm ok with this, in abstract.  It would be good to put up some
> intimidating
> comments to scare people away from using these flags for anything
> except for the AsmPrinter, because semantics are tricky enough as they
> are right now without new subtle bits to worry about.

I agree that this is a good approach, and that this should only be  
used for "random comments", the bits shouldn't have a semantic effect  
on the code.  Just put a strong comment on them, and that is enough.

> It even occurs to me to suggest putting the bits in a private member  
> in
> a class and making AsmPrinter a friend of that class in order to
> discourage accidental misuse, but that may be overreacting :-).

Yeah, probably not necessary ;)

-Chris