* implement wasmtime::component::flags! per #4308
This is the last macro needed to complete #4308. It supports generating a Rust
type that represents a `flags` component type, analogous to how the [bitflags
crate](https://crates.io/crates/bitflags) operates.
Signed-off-by: Joel Dice <joel.dice@fermyon.com>
* wrap `format_flags` output in parens
This ensures we generate non-empty output even when no flags are set. Empty
output for a `Debug` implementation would be confusing.
Signed-off-by: Joel Dice <joel.dice@fermyon.com>
* unconditionally derive `Lift` and `Lower` in wasmtime::component::flags!
Per feedback on #4414, we now derive impls for those traits unconditionally,
which simplifies the syntax of the macro.
Also, I happened to notice an alignment bug in `LowerExpander::expand_variant`,
so I fixed that and cleaned up some related code.
Finally, I used @jameysharp's trick to calculate bit masks without looping.
Signed-off-by: Joel Dice <joel.dice@fermyon.com>
* fix shift overflow regression in previous commit
Jamey pointed out my mistake: I didn't consider the case when the flag count was
evenly divisible by the representation size. This fixes the problem and adds
test cases to cover it.
Signed-off-by: Joel Dice <joel.dice@fermyon.com>
* support enums with more than 256 variants in derive macro
This addresses #4361. Technically, we now support up to 2^32 variants, which is
the maximum for the canonical ABI. In practice, though, the derived code for
enums with even just 2^16 variants takes a prohibitively long time to compile.
Signed-off-by: Joel Dice <joel.dice@fermyon.com>
* simplify `LowerExpander::expand_variant` code
Signed-off-by: Joel Dice <joel.dice@fermyon.com>
* support variant, enum, and union derives
This is the second stage of implementing #4308. It adds support for deriving
variant, enum, and union impls for `ComponentType`, `Lift`, and `Lower`. It
also fixes derived record impls for generic `struct`s, which I had intended to
support in my previous commit, but forgot to test.
Signed-off-by: Joel Dice <joel.dice@fermyon.com>
* deduplicate component-macro code
Thanks to @jameysharp for the suggestion!
Signed-off-by: Joel Dice <joel.dice@fermyon.com>
The more I read over this again the more I think that these should be
constants to explicitly indicate that we're supposed to be able to
optimize for them. Currently I'm predicting that adding memory64 support
will probably double the surface area of each trait (e.g. `lower32` and
`lower64`) rather than have a parameter passed around. This is in the
hopes that having specialized 32 and 64-bit paths will enable better
optimizations within each path instead of having to check all bounds
everywhere.
Additionally one day I'd like to have `fn load(bytes: &[u8;
Self::SIZE32])` but that doesn't work today in Rust.
This is the first stage of implementing
https://github.com/bytecodealliance/wasmtime/issues/4308, i.e. derive macros for
`ComponentType`, `Lift`, and `Lower` for composite types in the component model.
This stage only covers records; I expect the other composite types will follow a
similar pattern.
It borrows heavily from the work Jamey Sharp did in
https://github.com/bytecodealliance/wasmtime/pull/4217. Thanks for that, and
thanks to both Jamey and Alex Crichton for their excellent review feedback.
Thanks also to Brian for pairing up on the initial draft.
Signed-off-by: Joel Dice <joel.dice@fermyon.com>
