In #4252 I changed the signature and doc of the rust code, but forgot to change the doc for c.
Set strategy no longer returns error.
This commit fixes that.
This commit refactored `Config` to use a seperate `CompilerConfig` field instead
of operating on `CompilerBuilder` directly to make all its methods idempotent.
Fixes#4189
* Remove the module linking implementation in Wasmtime
This commit removes the experimental implementation of the module
linking WebAssembly proposal from Wasmtime. The module linking is no
longer intended for core WebAssembly but is instead incorporated into
the component model now at this point. This means that very large parts
of Wasmtime's implementation of module linking are no longer applicable
and would change greatly with an implementation of the component model.
The main purpose of this is to remove Wasmtime's reliance on the support
for module-linking in `wasmparser` and tooling crates. With this
reliance removed we can move over to the `component-model` branch of
`wasmparser` and use the updated support for the component model.
Additionally given the trajectory of the component model proposal the
embedding API of Wasmtime will not look like what it looks like today
for WebAssembly. For example the core wasm `Instance` will not change
and instead a `Component` is likely to be added instead.
Some more rationale for this is in #3941, but the basic idea is that I
feel that it's not going to be viable to develop support for the
component model on a non-`main` branch of Wasmtime. Additionaly I don't
think it's viable, for the same reasons as `wasm-tools`, to support the
old module linking proposal and the new component model at the same
time.
This commit takes a moment to not only delete the existing module
linking implementation but some abstractions are also simplified. For
example module serialization is a bit simpler that there's only one
module. Additionally instantiation is much simpler since the only
initializer we have to deal with are imports and nothing else.
Closes#3941
* Fix doc link
* Update comments
* Delete historical interruptable support in Wasmtime
This commit removes the `Config::interruptable` configuration along with
the `InterruptHandle` type from the `wasmtime` crate. The original
support for adding interruption to WebAssembly was added pretty early on
in the history of Wasmtime when there was no other method to prevent an
infinite loop from the host. Nowadays, however, there are alternative
methods for interruption such as fuel or epoch-based interruption.
One of the major downsides of `Config::interruptable` is that even when
it's not enabled it forces an atomic swap to happen when entering
WebAssembly code. This technically could be a non-atomic swap if the
configuration option isn't enabled but that produces even more branch-y
code on entry into WebAssembly which is already something we try to
optimize. Calling into WebAssembly is on the order of a dozens of
nanoseconds at this time and an atomic swap, even uncontended, can add
up to 5ns on some platforms.
The main goal of this PR is to remove this atomic swap on entry into
WebAssembly. This is done by removing the `Config::interruptable` field
entirely, moving all existing consumers to epochs instead which are
suitable for the same purposes. This means that the stack overflow check
is no longer entangled with the interruption check and perhaps one day
we could continue to optimize that further as well.
Some consequences of this change are:
* Epochs are now the only method of remote-thread interruption.
* There are no more Wasmtime traps that produces the `Interrupted` trap
code, although we may wish to move future traps to this so I left it
in place.
* The C API support for interrupt handles was also removed and bindings
for epoch methods were added.
* Function-entry checks for interruption are a tiny bit less efficient
since one check is performed for the stack limit and a second is
performed for the epoch as opposed to the `Config::interruptable`
style of bundling the stack limit and the interrupt check in one. It's
expected though that this is likely to not really be measurable.
* The old `VMInterrupts` structure is renamed to `VMRuntimeLimits`.
This commit removes the Lightbeam backend from Wasmtime as per [RFC 14].
This backend hasn't received maintenance in quite some time, and as [RFC
14] indicates this doesn't meet the threshold for keeping the code
in-tree, so this commit removes it.
A fast "baseline" compiler may still be added in the future. The
addition of such a backend should be in line with [RFC 14], though, with
the principles we now have for stable releases of Wasmtime. I'll close
out Lightbeam-related issues once this is merged.
[RFC 14]: https://github.com/bytecodealliance/rfcs/pull/14
Implement Wasmtime's new API as designed by RFC 11. This is quite a large commit which has had lots of discussion externally, so for more information it's best to read the RFC thread and the PR thread.
