Do not emit an `Expression::As` conversion for WGSL like `vec3(v)`
where `v` is already a `vec3`, or `mat2x3(m)` where `m` is already a
2x3 matrix. This doesn't fix any bugs, but it makes it clearer to the
reader of `Lowerer::construct` that no conversion can actually take
place in this case.
Some snapshots are affected because `As` expressions whose `width` is
`None` are bitcast expressions, which the constant evaluator does not
yet support. When this commit removes those `As` expressions, the
constant evaluator can reduce the expression to a `Literal` or
`ZeroValue`, which is then concealed by #2539.
* ConstantEvaluator::swizzle: Handle vector concatenation, indexing.
* Handle vector Compose expressions nested two deep.
* Move `flatten_compose` to `proc`, and make it a free function.
* [spv-out] Ensure that we flatten Compose for OpConstantCompose.
Change the validator to enforce WGSL's requirement that all variables
in the `function` and `private` address spaces must have constructible
types.
Mark the `RayQuery` type as `CONSTRUCTIBLE`, since it is intended to
be used for local variables.
Add a regression test.
Change printlns in the backend functions to say "generating" instead
of "writing" before calling the Naga backends. "Writing" suggests
writing output to a file; "generating" seems more accurate for calling
a backend.
Add a new type, `Input`, representing a particular Naga input file,
with methods to generate related paths - output files with a
particular extension, parameter files, and the input file itself.
Use this throughout `snapshots.rs` to generate paths.
Give `Input` utility methods for reading and writing files.
Rather than adding a `-glsl` suffix to the name, just rely on
`check_targets`' standard naming behavior, treating
`tests/in/variations.glsl` like any other snapshot input.
Remove the call to `Validator::validate` in `convert_spv`, since it
directly follows the call to `check_targets`, which also called
`Validator::validate`.
The only difference between the two is whether `Parameters::god_mode`
is respected, but this difference doesn't seem to have been
deliberate: at the time the call to `check_targets` was added to
`convert_spv` (5f21cf360, 2021-02-17), the two calls were exactly the
same.
Use `FastIndexSet`, rather than `FastHashSet`, for tracking global
declarations' dependencies, so that the order in which functions are
inserted into the `Module` is not dependent on the hash function.
Add a new Naga feature, `"compact"`, which adds a new function
`naga::compact::compact`, which removes unused expressions, types, and
constants from a `Module`.
