* Expand doc section about "what about `#![no_std]`?"
This commit expands the `#![no_std]` section of the documentation with
an FAQ-style set of words which explains in more detail about why we
don't support `#![no_std]` at this time, and how we can support it in
the future.
* Review comments
* Add some more words about -Zbuild-std
* Migrate back to `std::` stylistically
This commit moves away from idioms such as `alloc::` and `core::` as
imports of standard data structures and types. Instead it migrates all
crates to uniformly use `std::` for importing standard data structures
and types. This also removes the `std` and `core` features from all
crates to and removes any conditional checking for `feature = "std"`
All of this support was previously added in #407 in an effort to make
wasmtime/cranelift "`no_std` compatible". Unfortunately though this
change comes at a cost:
* The usage of `alloc` and `core` isn't idiomatic. Especially trying to
dual between types like `HashMap` from `std` as well as from
`hashbrown` causes imports to be surprising in some cases.
* Unfortunately there was no CI check that crates were `no_std`, so none
of them actually were. Many crates still imported from `std` or
depended on crates that used `std`.
It's important to note, however, that **this does not mean that wasmtime
will not run in embedded environments**. The style of the code today and
idioms aren't ready in Rust to support this degree of multiplexing and
makes it somewhat difficult to keep up with the style of `wasmtime`.
Instead it's intended that embedded runtime support will be added as
necessary. Currently only `std` is necessary to build `wasmtime`, and
platforms that natively need to execute `wasmtime` will need to use a
Rust target that supports `std`. Note though that not all of `std` needs
to be supported, but instead much of it could be configured off to
return errors, and `wasmtime` would be configured to gracefully handle
errors.
The goal of this PR is to move `wasmtime` back to idiomatic usage of
features/`std`/imports/etc and help development in the short-term.
Long-term when platform concerns arise (if any) they can be addressed by
moving back to `no_std` crates (but fixing the issues mentioned above)
or ensuring that the target in Rust has `std` available.
* Start filling out platform support doc
This commit adds the skeleton of a new set of documentation for
`wasmtime` in the existing `docs` directory. This documentation is
organized and compiled with [mdbook] which the Rust project uses for
most of its own documentation as well. At a previous meeting we
brainstormed a rough skeleton of what the documentation in this book
would look like, and I've transcribed that here for an example of how
this is rendered and how it can be laid out. No actual documentation is
written yet.
This commit also additionally adds necessary support to auto-publish
both this book documentation and API documentation every time a commit
is pushed to the `master` branch. All HTML will be automatically pushed
to the `gh-pages` branch so long as the CI passes, and this should get
deployed to https://cranestation.github.io/wasmtime.
I've done a few dry-runs and I think this'll all work, but we'll likely
tweak a few things here and there after running this through CI to make
sure everything looks just as we'd like. My hope though is that after
this lands we can start actually filling out all the documentation and
being able to review it as well.
[mdbook]: https://crates.io/crates/mdbook
