GLSL_EXT_buffer_reference with in/out interface

[spencer-lunarg]

Discussed a lot in https://gitlab.khronos.org/spirv/SPIR-V/-/issues/779 this is untested and there is a VUID-StandaloneSpirv-Input-09557 in Vulkan and this should not be allowed, so explicitly marking it

cc @jeffbolznv as author and also @gnl21

[spencer-lunarg]

@gnl21 still new to the GLSL spec process, but KhronosGroup/glslang#3878 was merged already

[gnl21]

Sorry, my fault.

Reading the spec change, the thing that it sounds like it's trying to ban is already banned in the text, and I can't construct something I think this change should apply to. Can you give an example of some shader code that you're talking about?

[spencer-lunarg]

#version 450
#extension GL_EXT_buffer_reference : enable

layout(buffer_reference) buffer X {
    int payload;
};
layout(location = 1) flat in X x;

void main() {}

hmm, I guess re-reading this, it sound like I ment layout(location = 1) flat in buffer_reference X x; which ya, is already banned

If you think the current GLSL spec is "good as is" then feel free to close. If you think I am just messing up the GLSL terms, happy to update the PR too