This commit deletes the old `snapshot_0` implementation of wasi-common,
along with the `wig` crate that was used to generate bindings for it.
This then reimplements `snapshot_0` in terms of
`wasi_snapshot_preview1`. There were very few changes between the two
snapshots:
* The `nlink` field of `FileStat` was increased from 32 to 64 bits.
* The `set` field of `whence` was reordered.
* Clock subscriptions in polling dropped their redundant userdata field.
This makes all of the syscalls relatively straightforward to simply
delegate to the next snapshot's implementation. Some trickery happens to
avoid extra cost when dealing with iovecs, but since the memory layout
of iovecs remained the same this should still work.
Now that `snapshot_0` is using wiggle we simply have a trait to
implement, and that's implemented for the same `WasiCtx` that has the
`wasi_snapshot_preview1` trait implemented for it as well. While this
theoretically means that you could share the file descriptor table
between the two snapshots that's not supported in the generated bindings
just yet. A separate `WasiCtx` will be created for each WASI module.
This makes the value of `state.reachable()` inaccurate when observing at
the tail of functions (in the post-function hook) after an ordinary
return instruction.
In some cases, it is useful to do some work at entry to or exit from a
Cranelift function translated from WebAssembly. This PR adds two
optional methods to the `FuncEnvironment` trait to do just this,
analogous to the pre/post-hooks on operators that already exist.
This PR also includes a drive-by compilation fix due to the latest
nightly wherein `.is_empty()` on a `Range` ambiguously refers to either
the `Range` impl or the `ExactSizeIterator` impl and can't resolve.
* Enhance wiggle to generate its UserErrorConverstion trait with a function that returns
a Result<abi_err, String>. This enhancement allows hostcall implementations using wiggle
to return an actionable error to the instance (the abi_err) or to terminate the instance
using the String as fatal error information.
* Enhance wiggle to generate its UserErrorConverstion trait with a function that returns
a Result<abi_err, String>. This enhancement allows hostcall implementations using wiggle
to return an actionable error to the instance (the abi_err) or to terminate the instance
using the String as fatal error information.
* Enhance the wiggle/wasmtime integration to leverage new work in ab7e9c6. Hostcall
implementations generated by wiggle now return an Result<abi_error, Trap>. As a
result, hostcalls experiencing fatal errors may trap, thereby terminating the
wasmtime instance. This enhancement has been performed for both wasi snapshot1
and wasi snapshot0.
* Update wasi-nn crate to reflect enhancement in issue #2418.
* Update wiggle test-helpers for wiggle enhancement made in issue #2418.
* Address PR feedback; omit verbose return statement.
* Address PR feedback; manually format within a proc macro.
* Address PR feedback; manually format proc macro.
* Restore return statements to wasi.rs.
* Restore return statements in funcs.rs.
* Address PR feedback; omit TODO and fix formatting.
* Ok-wrap error type in assert statement.
With the module linking proposal the field name on imports is now
optional, and only the module is required to be specified. This commit
propagates this API change to the boundary of wasmtime's API, ensuring
consumers are aware of what's optional with module linking and what
isn't. Note that it's expected that all existing users will either
update accordingly or unwrap the result since module linking is
presumably disabled.
AFAIK this isn't really necessary nowadays given the prevalence of
rustfmt, and for whatever reason the Rust plugin for vim uses this file
in lieu of all other options, meaning it doesn't pass `--edition 2018`
by default which has been causing issues as I've been working on `async`
stuff. In any case I don't think we need the file regardless, so this
commit deletes it.
This end result was previously enacted by carrying a `SourceLoc` on
every load/store, which was somewhat cumbersome, and only indirectly
encoded metadata about a memory reference (can it trap) by its presence
or absence. We have a type for this -- `MemFlags` -- that tells us
everything we might want to know about a load or store, and we should
plumb it through to code emission instead.
This PR attaches a `MemFlags` to an `Amode` on x64, and puts it on load
and store `Inst` variants on aarch64. These two choices seem to factor
things out in the nicest way: there are relatively few load/store insts
on aarch64 but many addressing modes, while the opposite is true on x64.
This PR makes use of the support in #2366 for sinking effectful
instructions and merging them with consumers. In particular, on x86, we
want to make use of the ability of many instructions to load one operand
directly from memory. That is, instead of this:
```
movq 0(%rdi), %rax
addq %rax, %rbx
```
we want to generate this:
```
addq 0(%rdi), %rax
```
As described in more detail in #2366, sinking and merging the load is
only possible under certain conditions. In particular, we need to ensure
that the use is the *only* use (otherwise the load happens more than
once), and we need to ensure that it does not move across other
effectful ops (see #2366 for how we ensure this).
This change is actually fairly simple, given that all the framework is
in place: we simply pattern-match a load on one operand of an ALU
instruction that takes an RMI (reg, mem, or immediate) operand, and
generate the mem form when we match.
Also makes a drive-by improvement in the x64 backend to use
statically-monomorphized `LowerCtx` types rather than a `&mut dyn
LowerCtx`.
On `bz2.wasm`, this results in ~1% instruction-count reduction. More is
likely possible by following up with other instructions that can merge
memory loads as well.
