The compiler will mark struct members with those builtins, but won't
declare the capability until that member is accessed by some executable
instruction.
Test changes:
- spv.430.vert: was missing ClipDistance capability.
- spv.precise.tese: remove TessellationPointSize capability.
Spec for decorating the OpVariable:
"The remaining variables listed by OpEntryPoint with the Input or Output storage class form the user-defined variable interface. These variables must be identified with a Location decoration"
Spec for decorating struct type:
"The layout of a structure type used as an Input or Output depends on whether it is also a Block (i.e. has a Block decoration).
If it is a not a Block, then the structure type must have a Location decoration"
These capabalities were added on declaration of the members, but
that is considered too aggressive, as those members are automatically
declared in some shaders that don't use them. Now, actual access
is needed to make the capabalities be declared.
This fixes some vulkanCTS tests that use struct arrays as a member of in/out interface blocks.
From Vulkan spec:
"If it is a not a Block, then the structure type must have a Location decoration. Its members are assigned consecutive locations in their declaration order, with the first member assigned to the location specified for the structure type. >>>>> The members, and their nested types, must not themselves have Location decorations <<<<"
From SPIR-V spec:
"When applied to structure-type members, the Decorations Noperspective, Flat, Patch, Centroid, and Sample can only be applied to the top-level members of the structure type. (Nested objects' types cannot be structures whose members are decorated with these decorations.)"
Before, it was only including explicit interface, sufficient for IO-Block-declared
oriented interface, but not sufficient for all modes GLSL might be used with
SPIR-V.
Two things are accomplished now:
1) each id will appear exactly once
2) the OpEntryPoint list will union static use with declarations
Structured control-flow rules allow leaving the middle of a construct through
a return, but not through a jump to a block that does a return.
Addresses issue #58.
