Implement GL_EXT_long_vector

[jeffbolznv]

GLSL spec: KhronosGroup/GLSL#297
SPIR-V spec: KhronosGroup/SPIRV-Registry#377

[jeffbolznv]

Temporary until KhronosGroup/SPIRV-Tools#6471 is merged.

[dnovillo]

Looks fine overall.

• For coopvecNV, I think we allow conversions from/to vector types. Is this still true? Maybe add a test for this.
• I did not see a test for GL_EXT_buffer_reference for long vectors. That's allowed, I think?
• long vectors in uniform and buffer blocks are not allowed, right? I don't think we are validating this (or even testing?)

layout(constant_id = 0) const uint N = 5;
layout(set=0, binding=0, std140) uniform UBO {
vector<float, N> v; // I think this should be invalid?
};

[jeffbolznv]

For coopvecNV, I think we allow conversions from/to vector types. Is this still true? Maybe add a test for this.

Yes, conversions are allowed. There's some testing for this in spv.longVector.comp:testfuncs() (including parameter passing).

I did not see a test for GL_EXT_buffer_reference for long vectors. That's allowed, I think?

This was missing, I've added it to spv.longVectorStorage.comp.

long vectors in uniform and buffer blocks are not allowed, right? I don't think we are validating this (or even testing?)

This is allowed, it's tested in spv.longVectorStorage.comp.

I'll push an update shortly.

[dnovillo]

Thanks. OK to go in as soon as the SPIRV-Tools changes have been submitted to ToT.