Most of the CLI crates were already in the 2018 edition, and it turns
out that one of the macro crates was already in the 2018 edition so we
may as well move everything to the 2018 edition!
Always nice to remove those `extern crate` statements nowadays!
This commit also does a `cargo fmt --all` to make sure we're conforming
with style again.
Using `unsafe` was just a little too eager there so let's use an
off-the-shelf solution for solving the actual problem we have, which is
to allocate strings with a lifetime of `Interner` rather than
deduplicating strings.
This commit migrates away from using Serde for the custom section in
wasm executables. This is a refactoring of a purely-internal data
structure to `wasm-bindgen` and should have no visible functional change
on users.
The motivation for this commit is two fold:
* First, the compile times using `serde_json` and `serde_derive` for the
syntax extension isn't the most fun.
* Second, eventually we're going to want to stablize the layout of the
custom section, and it's highly unlikely to be json!
Primarily, though, the intention of this commit is to improve the
cold-cache compile time of `wasm-bindgen` by ensuring that for new users
this project builds as quickly as possible. By removing some heavyweight
dependencies from the procedural macro, `serde`, `serde_derive`, and
`serde_json`, we're able to get a pretty nice build time improvement for
the `wasm-bindgen` crate itself:
| | single-core build | parallel build |
|-------------|-------------------|----------------|
| master | 36.5s | 17.3s |
| this commit | 20.5s | 11.8s |
These are't really end-all-be-all wins but they're much better
especially on the spectrum of weaker CPUs (in theory modeled by the
single-core case showing we have 42% less CPU work in theory).
