Optimize the ABI boundary of wasm-compiled proc macros #14
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This commit switches to per-API function calls into the host runtime to
instead minimizing the amount of times a wasm blob calls the host
runtime. This requires a bulk transfer of the entire `TokenStream` up
front into the wasm blob, along with a bulk transfer from wasm back into
the native runtime afterwards.
Current a bincode-like encoding is used to serialize and deserialize
`TokenStream`, with the data format duplicated across a few
`{encode,decode}.rs` files. Eventually it'd probably be good to use a
macro_rules macro or similar to avoid this duplication, but for now it's
not a whole lot of code anyway.
This makes the wasm proc macro sort of hard for now, but I hope to
improve that in subsequent commits.
Additionally the `proc-macro2` shadow crate has been updated to more
closely match the fallback of `proc-macro2` itself, storing most
information in-memory as opposed to storing handles.
Use a small macro which looks like `#[proc_macro]` and friends which automatically does the translation for us. Additionally there's no need to set the panic hook any more because that'll automatically get registered.
No need for these with a scoped import module
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This is a culmination of the following set of ideas:
I figured these are all large enough changes that this'll want to eventually be bumped to 0.2, so I've started pruning APIs exposed by
wattin this PR as well. This updates the README with general high-level docs of how to usewattas well.This should inch us closer to a "level playing field" between natively compiled procedural macros and wasm-compiled procedural macros when using a JIT!