[LLVMdev] registers as home location

[shreyas krishnan]

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.
 I would like to pin the register through a pass and so I dont know
which registers ends up being used for a particular value before hand

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.

   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.

thanks again
shrey


On Thu, Jul 16, 2009 at 2:05 PM, Jeffrey Yasskin<jyasskin at google.com> wrote:
> Chris recently wrote up a way to do this at
> http://nondot.org/sabre/LLVMNotes/GlobalRegisterVariables.txt
>
> On Thu, Jul 16, 2009 at 1:53 PM, shreyas krishnan<shreyas76 at gmail.com> wrote:
>> Hi
>>   As part of a requirement that I have, I would like to have some
>> globals reside in registers always. So these variables would not have
>> a home location in memory.
>> I realize the code generated would also need to be aware of this. I do
>> have some ideas on how to change the code appropriately.  But right
>> now, I am more concerned about how to fit this requirement (sort of
>> interprocedural) into the existing LLVM register allocation framework.
>> While I can as part of pre regalloc pass allocate globals to
>> registers, how can I share this information between allocation of
>> different functions.
>>
>> Allocation efficiency is not as much a concern and I am ok with doing
>> the allocation as a pre ra pass.
>> I will appreciate any pointers !
>> Shrey
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>