* When debugging a pixel or doing quad overdraw we replace the pixel shader and
patch in our own UAV. Previously we were moving other UAVs out of the way that
were visible to the pixel shader, but this fails if a UAV is visible to all
stages and used in a vertex stage.
* Now instead for pixel shader inputs we pick a free space and use it. For quad
overdraw we pick an arbitrary high space to hopefully use the precompiled
shader, and if it's somehow not free we recompile the shader with a free
space.
baldurk
220b26aa59