[LLVMdev] registers as home location

shreyas krishnan shreyas76 at gmail.com
Thu Jul 16 15:27:28 PDT 2009


Thanks Eli. At a implementation level, I am wondering if there is any
target specific class that I can use to store this information and use
it in the  modified allocator later.

thanks
shrey

On Thu, Jul 16, 2009 at 3:12 PM, Eli Friedman<eli.friedman at gmail.com> wrote:
> On Thu, Jul 16, 2009 at 2:41 PM, shreyas krishnan<shreyas76 at gmail.com> wrote:
>> Thanks Eli, Jaffrey for the pointer!
>>
>> A couple of further questions if I may
>> 1. Isnt this assuming that register being pinned to is always esi when
>> it comes to using a calling convention.
>
> You'd need a separate calling convention for each possible set of
> registers pinned.  The combinatoric possibilities can get ugly, but
> you probably only need a small fraction of the possibilities.
>
>> 2. I would also like to allocate some small aggregates into registers.
>> I understand that the code generation would need to be non trivially
>> modified to do this.
>
> You can always just split them in your pass... I don't know off the
> top of my head whether returning a nested structure works at the
> moment.
>
>>   I am wondering if it would be possible to create a map of this
>> information and using it in a modified existing allocator.
>> Modification would make sure the already allocated registers are not
>> available.
>
> You could, but it would be an ugly hack.
>
> -Eli
>
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