When compiling test shaders, we were setting SK_FRAGCOORD_BUILTIN on the
`coords` parameter to main() instead of SK_MAIN_COORDS_BUILTIN. These
two built-ins don't have the same type (float2 vs. float4) and don't
mean quite the same thing.
The SPIR-V code generator saw a variable with the SK_FRAGCOORD_BUILTIN
builtin value and assumed the presence of a global variable named
`sk_FragCoord`, which didn't exist (because it was never referenced in
the code, so it was never cloned in from the sksl_frag module).
This is only a concern when compiling test shaders with skslc; real
shaders don't hit these code paths. The generated code here is still
imperfect; if you look closely, you'll see the GLSL and Metal code is
referencing the `coords` variable but it's never declared anywhere.
Change-Id: I3ad249469927ff35eb1e75d6536f95317502708f
Bug: skia:12340
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/440520
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
9078a89b26