Fix varying output structs in GLSL source (#8501)

Closes #8500.

`slang-ir-translate-global-varying-var.cpp` turns the global varying
outputs into a struct that's returned from the entry point. Currently,
there's a problem when one of the outputs is a struct. It always creates
a generic `IRTypeLayout`, even when a correct type layout already
exists. Somehow, this appears to work when the global varying outputs
aren't structs.

The crash occurs in
`slang-ir-glsl-legalize.cpp:createGLSLGlobalVaryingsImpl()`. It
correctly handles the generated outer struct, but when that contains an
inner struct, it's been given a non-struct type layout and crashes.

This PR uses the correct layout if found, instead of generating a broken
placeholder. This matches the behaviour that has already been
implemented for inputs.

Additionally, I removed a call to `addResourceUsage` from both the input
and output side. I can't see any way in which it would've affected
anything, the layout builder is never used after that call and it
doesn't retroactively modify the layout that was already created.

0 files changed, 0 insertions, 0 deletions