Allow type-fluid GLSL-style vec2(int, bool) ctors in SkSL.

Note that GLSL accepts these sorts of constructors natively, but Metal
and SPIR-V do not. In the generated IR we actually add a cast for
subexpressions where the type does not match. These casts can be seen in
the final output for both GLSL (where they are no-ops) and Metal/SPIR-V
(where they are essential).

This change exposed some missing SPIR-V functionality (vector casts do
not support bool types). This can be fixed up in a followup CL; these
casts were previously disallowed by SkSL entirely, so there won't be any
of them in existing code.

Change-Id: I54ae922e91b38bed032537496428747a081dc774
Bug: skia:11164, skia:11171
Reviewed-by: Brian Osman <>
Commit-Queue: John Stiles <>
Auto-Submit: John Stiles <>
6 files changed