We (Zeb, mostly) have also been omitting the vkd3d_/vkd3d_shader_ prefix on new (module) internal API. I'm not too bothered by either variant, but if you prefer, you could also go with "struct sm6_signature" and "sm6_signature_cleanup()".
My reasoning is that firstly, I like a clear distinction between what is and isn't external API, and secondly, typing out vkd3d_shader everywhere makes names annoyingly long.
I've said this a few times, but along the same lines, I'd like to propose giving struct vkd3d_shader_instruction (and related structures / functions) a different, shorter prefix in place of "vkd3d_shader". Some ideas: - "ir" (to match the file name. Granted, this isn't the only IR in vkd3d-shader, but it's also probably the only one that will have a generic role in every transformation), - "vsir" (an abbreviation of "vkd3d-shader IR"), - "vazir" (a more cute/clever name, Persian for "minister" but which I understand can also mean something close to "helper" or "assistant", which seems quite fitting. I've tried to also make it into an acronym but the 'z' makes things difficult).