WebAssembly (Wasm) interpreter.
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wasmi
- WebAssembly (Wasm) Interpreter
wasmi
is an efficient WebAssembly interpreter with low-overhead and support
for embedded environment such as WebAssembly itself.
At Parity we are using wasmi
in Substrate
as the execution engine for our WebAssembly based smart contracts.
Furthermore we run wasmi
within the Substrate runtime which is a WebAssembly
environment itself and driven via Wasmtime at the time of this writing.
As such wasmi
's implementation requires a high degree of correctness and
Wasm specification conformance.
Since wasmi
is relatively lightweight compared to other Wasm virtual machines
such as Wasmtime it is also a decent option for initial prototyping.
Distinct Features
The following list states some of the distinct features of wasmi
.
WebAssembly Proposals
The new wasmi
engine supports a variety of WebAssembly proposals and will support even more of them in the future.
WebAssembly Proposal Status Comment
mutable-global
✅
Since version 0.14.0
.
saturating-float-to-int
✅
Since version 0.14.0
.
sign-extension
✅
Since version 0.14.0
.
multi-value
✅
Since version 0.14.0
.
bulk-memory
✅
Since version 0.24.0
. (#628)
reference-types
✅
Since version 0.24.0
. (#635)
simd
❌
Unlikely to be supported.
tail-calls
✅
Since version 0.28.0
. (#683)
extended-const
✅
Since version 0.29.0
. (#707)
function-references
📅
Planned but not yet implemented. (#774)
gc
📅
Planned but not yet implemented. (#775)
multi-memory
📅
Planned but not yet implemented. (#776)
threads
📅
Planned but not yet implemented. (#777)
relaxed-simd
❌
Unlikely to be supported since simd
is unlikely to be supported.
WASI
👨🔬
Experimental support via the wasmi_wasi
crate or the wasmi
CLI application.
Usage As CLI Application
Install the newest wasmi
CLI version via:
cargo install wasmi_cli
Then run arbitrary wasm32-unknown-unknown
Wasm blobs via:
wasmi_cli <WASM_FILE> <FUNC_NAME> [<FUNC_ARGS>]*As Rust Library
Any Rust crate can depend on the wasmi
crate
in order to integrate a WebAssembly intepreter into their stack.
Refer to the wasmi
crate docs to learn how to use the wasmi
crate as library.
Development Building
Clone wasmi
from our official repository and then build using the standard cargo
procedure:
git clone https://github.com/paritytech/wasmi.git cd wasmi cargo buildTesting
In order to test wasmi
you need to initialize and update the Git submodules using:
git submodule update --init --recursive
Alternatively you can provide --recursive
flag to git clone
command while cloning the repository:
git clone https://github.com/paritytech/wasmi.git --recursive
After Git submodules have been initialized and updated you can test using:
cargo test --workspaceBenchmarks
In order to benchmark wasmi
use the following command:
cargo bench
You can filter which set of benchmarks to run:
cargo bench translate
cargo bench instantiate
cargo bench execute
We maintain a timeline for benchmarks of every commit to master
that can be viewed here.
Supported Platforms
Supported platforms are primarily Linux, MacOS, Windows and WebAssembly.
Other platforms might be working but are not guaranteed to be so by the wasmi
maintainers.
Use the following command in order to produce a WebAssembly build:
cargo build --no-default-features --target wasm32-unknown-unknownProduction Builds
In order to reap the most performance out of wasmi
we highly recommended
to compile the wasmi
crate using the following Cargo profile
:
[profile.release] lto = "fat" codegen-units = 1
When compiling for the WebAssembly target we highly recommend to post-optimize
wasmi
using Binaryen's wasm-opt
tool since our experiments displayed a
80-100% performance improvements when executed under Wasmtime and also
slightly smaller Wasm binaries.
License
wasmi
is primarily distributed under the terms of both the MIT
license and the APACHE license (Version 2.0), at your choice.
See LICENSE-APACHE
and LICENSE-MIT
for details.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in wasmi
by you, as defined in the APACHE 2.0 license, shall be
dual licensed as above, without any additional terms or conditions.
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