Add validation for invalid layout decoration usage

[alan-baker]

• Checks that Block, BufferBlock, Offset, ArrayStride, and MatrixStride are not used in a Vulkan environment in disallowed storage classes

[spencer-lunarg]

@alan-baker so for something in GLSL like

#version 450

struct Bar {
    uint x;
    uint y;
    uint z[2];
};

layout(set = 0, binding = 0, std430) buffer foo {
    uvec4 a;
    Bar b; // size 16 at offset 16
    uint c;
};

void main() {
    Bar new_bar;
    b = new_bar;
}

this will pass spirv-val if using --target-env vulkan1.1 (https://godbolt.org/z/bjKodYPKG)

but fail here with 1.2

I guess trying to figure out what spec change causes this to fail from 1.1 to 1.2

[alan-baker]

This chapter describes valid uses for a set of SPIR-V decorations. Any other use of one of these decorations is invalid, with the exception that, when using SPIR-V versions 1.4 and earlier: Block, BufferBlock, Offset, ArrayStride, and MatrixStride can also decorate types and type members used by variables in the Private and Function storage classes.

Vulkan 1.2 is considered SPIR-V 1.5 (for the assembler) so that prevents putting layouts on types used in function variables.

Looks like I misread the spec though and should change the conditions to <= 1.4.

[spencer-lunarg]

Ok, this was in the Shader Interfaces section of the Vulkan Spec (I was searching only in the SPIR-V spec)

[alan-baker]

That fix is #6023