Promote member decorations to descriptor binding decorations

[panos-lunarg]

This is basically a follow-up on #141. Decorations like readonly or writeonly are being parsed but they are only applied to descriptor block variables. This patch scans each descriptor's member decorations and those that are common to all members are promoted to the descriptor as well.

[CLAassistant]

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[panos-lunarg]

With the intention of adding a test for this change I attempt to reuse the non_writtable_image.spv shader. Because decorations were not being tested for descriptor bindings I had to touch all .yaml files. Hope it is the right way

[panos-lunarg]

I assume you mean the following example:

layout(set=0, binding=0) buffer storage_buffer {
    writeonly float a; // non-readable
    readonly float b; // non-writable
} foo;

In the above example since none of the decorations are common between all member, none will be promoted to the whole descriptor. In order to get both readonly and writeonly promoted to the whole descriptor all member must have the decorations. Something like this:

layout(set=0, binding=0) buffer storage_buffer {
    readonly writeonly float a; // both non-readable and non-writable
    readonly writeonly float b; // both non-readable and non-writable
} foo;

This indeed will mark storage_buffer as both readonly and writeonly but if glslang allows you to mark a member with both then I don't see the problem in promoting both to the descriptor

[spencer-lunarg]

In order to get both readonly and writeonly promoted to the whole descriptor all member must have the decorations.

Awww, I see, yes, you are doing &= on these

Could you quick add my example as a test case (show casing this code works like we intend it to) then I think I'm convinced this is ready to go