| d8f7c77f | 25-Apr-2024 |
Alex Crichton <[email protected]> |
Start migrating some Wasmtime crates to no_std (#8463)
* Start migrating some Wasmtime crates to no_std
This commit is the first in what will be multiple PRs to migrate
Wasmtime to being compatible
Start migrating some Wasmtime crates to no_std (#8463)
* Start migrating some Wasmtime crates to no_std
This commit is the first in what will be multiple PRs to migrate
Wasmtime to being compatible with `#![no_std]`. This work is outlined
in #8341 and the rough plan I have in mind is to go on a crate-by-crate
basis and use CI as a "ratchet" to ensure that `no_std` compat is
preserved. In that sense this PR is a bit of a template for future PRs.
This PR migrates a few small crates to `no_std`, basically those that
need no changes beyond simply adding the attribute. The nontrivial parts
introduced in this PR are:
* CI is introduced to verify that a subset of crates can indeed be
built on a `no_std` target. The target selected is
`x86_64-unknown-none` which is known to not have `std` and will result
in a build error if it's attempted to be used.
* The `anyhow` crate, which `wasmtime-jit-icache-coherence` now depends
on, has its `std` feature disabled by default in Wasmtime's workspace.
This means that some crates which require `std` now need to explicitly
enable the feature, but it means that by-default its usage is
appropriate for `no_std`.
The first point should provide CI checks that compatibility with
`no_std` indeed works, at least from an "it compiles" perspective. Note
that it's not sufficient to test with a target like
`x86_64-unknown-linux-gnu` because `extern crate std` will work on that
target, even when `#![no_std]` is active.
The second point however is likely to increase maintenance burden
in Wasmtime unfortunately. Namely we'll inevitably, either here or in
the future, forget to turn on some feature for some crate that's not
covered in CI checks. While I've tried to do my best here in covering it
there's no guarantee that everything will work and the combinatorial
explosion of what could be checked in CI can't all be added to CI.
Instead we'll have to rely on bug fixes, users, and perhaps point
releases to add more use cases to CI over time as we see fit.
* Add another std feature
* Another std feature
* Enable anyhow/std for another crate
* Activate `std` in more crates
* Fix miri build
* Fix compile on riscv64
prtest:full
* Fix min-platform example build
* Fix icache-coherence again
show more ...
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