This commit refactors the Wasmtime CLI tools to use `structopt` instead of
`docopt`.
The `wasmtime` tool now has the following subcommands:
* `config new` - creates a new Wasmtime configuration file.
* `run` - runs a WebAssembly module.
* `wasm2obj` - translates a Wasm module to native object file.
* `wast` - runs a test script file.
If no subcommand is specified, the `run` subcommand is used. Thus,
`wasmtime foo.wasm` should continue to function as expected.
The `wasm2obj` and `wast` tools still exist, but delegate to the same
implementation as the `wasmtime` subcommands. The standalone `wasm2obj` and
`wast` tools may be removed in the future in favor of simply using `wasmtime`.
Included in this commit is a breaking change to the default Wasmtime
configuration file: it has been renamed from `wasmtime-cache-config.toml` to
simply `config.toml`. The new name is less specific which will allow for
additional (non-cache-related) settings in the future.
There are some breaking changes to improve command line UX:
* The `--cache-config` option has been renamed to `--config`.
* The `--create-config-file` option has moved to the `config new` subcommand.
As a result, the `wasm2obj` and `wast` tools cannot be used to create a new
config file.
* The short form of the `--optimize` option has changed from
`-o` to `-O` for consistency.
* The `wasm2obj` command takes the output object file as a
required positional argument rather than the former required output *option*
(e.g. `wasmtime wasm2obj foo.wasm foo.obj`).
* Remove usage of `CompilationStrategy` from `Config`
This commit removes the public API usage of the internal
`CompilationStrategy` enumeration from the `Config` type in the
`wasmtime` crate. To do this the `enum` was copied locally into the
crate and renamed `Strategy`. The high-level description of this change
is:
* The `Config::strategy` method now takes a locally-defined `Strategy`
enumeration instead of an internal type.
* The contents of `Strategy` are always the same, not relying on Cargo
features to indicate which variants are present. This avoids
unnecessary downstream `#[cfg]`.
* A `lightbeam` feature was added to the `wasmtime` crate itself to
lightbeam compilation support.
* The `Config::strategy` method is now fallible. It returns a runtime
error if support for the selected strategy wasn't compiled in.
* The `Strategy` enum is listed as `#[non_exhaustive]` so we can safely
add variants over time to it.
This reduces the public crate dependencies of the `wasmtime` crate
itself, removing the need to reach into internal crates even more!
cc #708
* Fix fuzz targets
* Update nightly used to build releases
* Run rustfmt
* 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
