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
Implemented `SqmulRoundSat` for the Cranelift interpreter, performing
QN-format fixed point multiplication for 16 and 32-bit integers in
SIMD vectors.
Copyright (c) 2021, Arm Limited
- Add relocation handling needed after PR #3275
- Fix incorrect handling of signed constants detected by PR #3056 test
- Fix LabelUse max pos/neg ranges; fix overflow in buffers.rs
- Disable fuzzing tests that require pre-built v8 binaries
- Disable cranelift test that depends on i128
- Temporarily disable memory64 tests
Transforming this into a generic function is proving to be a challenge
since most of the necessary methods are not in a trait. We also need to
cast between the signed and unsigned types, which is difficult to do
in a generic function.
This can be solved for example by adding the num crate as a dependency.
But adding a dependency just to solve this issue seems a bit much.
* Use rsix to make system calls in Wasmtime.
`rsix` is a system call wrapper crate that we use in `wasi-common`,
which can provide the following advantages in the rest of Wasmtime:
- It eliminates some `unsafe` blocks in Wasmtime's code. There's
still an `unsafe` block in the library, but this way, the `unsafe`
is factored out and clearly scoped.
- And, it makes error handling more consistent, factoring out code for
checking return values and `io::Error::last_os_error()`, and code that
does `errno::set_errno(0)`.
This doesn't cover *all* system calls; `rsix` doesn't implement
signal-handling APIs, and this doesn't cover calls made through `std` or
crates like `userfaultfd`, `rand`, and `region`.
Implemented `Smulhi` for the Cranelift interpreter, performing signed
integer multiplication and producing the high half of a double-length
result.
Copyright (c) 2021, Arm Limited
Implemented `WideningPairwiseDotProductS` to perform sign-extending
length-doubling multiplication on corresponding elements from two
`i16x8` SIMD vectors, performing a pairwise add on the results (thus
returning `i32x4`).
Copyright (c) 2021, Arm Limited
Implemented the following Opcodes for the Cranelift interpreter:
- `Unarrow` to combine two SIMD vectors into a new vector with twice
the lanes but half the width, with signed inputs which are clamped to
`0x00`.
- `Uunarrow` to perform the same operation as `Unarrow` but treating
inputs as unsigned.
- `Snarrow` to perform the same operation as `Unarrow` but treating
both inputs and outputs as signed, and saturating accordingly.
Note that all 3 instructions saturate at the type boundaries.
Copyright (c) 2021, Arm Limited
Implemented the following Opcodes for the Cranelift interpreter:
- `VhighBits` to reduce a vector to a scalar integer formed by
concatenating the MSB of each lane.
- `Vselect` to select lanes from two vectors controlled by a boolean
vector.
Copyright (c) 2021, Arm Limited
