[Mesa-dev] [PATCH 2/2] [RFC] radv: add scratch support for spilling.

[Dave Airlie]

On 11 October 2016 at 05:50, Dave Airlie <airlied at gmail.com> wrote:
> On 10 October 2016 at 21:45, Arsenault, Matthew
> <Matthew.Arsenault at amd.com> wrote:
>> I don't like adding explicit IR arguments for ABI arguments, especially this
>> one. Adding a special case for the first index feels dirty. The rest of llvm
>> also won't be aware of the specialness of the argument. It would be
>> problematic because bugpoint would eliminate the unused argument and then
>> codegen would have to fail in some way when the argument is missing
>>
>
> We should just hardcode the behaviour and switch both radv/radeonsi
> over in one go?
>
> I'll try and code up, using the first 64-bits of the first buffer
> pointed to by userdata 0/1,
> to store things.

I've looked at doing a dword fetch from the first two words of the 0/1 userdata,

It's not optimal for vulkan unfortunately, since the idea I had was per command
buffer I just allocate one scratch buffer of the size required at the end, and
patch it in at the start of the command buffer. However in the first
slot I was going
to use the push constants/dynamic buffer to store the value, however it looks
like I need to keep a list of everyone of these buffers I emit, and
backpatch them
all. It might not be too insane, just a slight bump in the keeping it simple.

Dave.