dirkschumacher/wasmr

Execute WebAssembly from R using wasmer

WebAssembly in R using wasmer

The goal of wasmr is to run WebAssembly code from R using the wasmer runtime.

This is a early version with probably bugs, missing features and not the best code quality. But it already works and I am happy to hear feedback. The goal is that this package evolves into something stable.

The package is mainly written in C++ using the C API of the wasmer runtime which is written in rust. You therefore need a rust compiler to install the package.

Installation

remotes::install_github("dirkschumacher/wasmr")

Also make sure to have a very recent rust compiler. The best way to install the rust toolchain is to use rustup.

Example

library(wasmr)

f <- system.file("examples/sum.wasm", package = "wasmr")
instance <- instantiate(f)
instance$exports$sum(10, 20)
#> [1] 30

f <- system.file("examples/hello.wasm", package = "wasmr")
instance <- instantiate(f)
memory_pointer <- instance$exports$hello()
hi <- instance$memory$get_memory_view(memory_pointer)
rawToChar(hi$get(1:11))
#> [1] "Hello world"

f <- system.file("examples/fib.wasm", package = "wasmr")
instance <- instantiate(f)
instance$exports$fib(20)
#> [1] 6765

fib <- function(n) {
  if (n < 2) return(n)
  fib(n - 1) + fib(n - 2)
}

microbenchmark::microbenchmark(
  instance$exports$fib(20),
  fib(20)
)
#> Unit: microseconds
#>                      expr      min        lq       mean    median
#>  instance$exports$fib(20)   71.143   88.4745   158.3407   139.814
#>                   fib(20) 8037.195 9556.2085 13024.0362 10415.965
#>         uq       max neval
#>    150.472  1019.363   100
#>  14568.746 48506.287   100

Memory

f <- system.file("examples/fib.wasm", package = "wasmr")
instance <- instantiate(f)
instance$memory$get_memory_length()
#> [1] 2

# grow the number of pages
instance$memory$grow(1)
instance$memory$get_memory_length()
#> [1] 3

f <- system.file("examples/hello.wasm", package = "wasmr")
instance <- instantiate(f)
memory_pointer <- instance$exports$hello()
memory <- instance$memory$get_memory_view(memory_pointer)
memory$get(1:11)
#>  [1] 48 65 6c 6c 6f 20 77 6f 72 6c 64
rawToChar(memory$get(1:11))
#> [1] "Hello world"

# you can also write to the internal memory
memory$set(5:6, charToRaw("o_"))
rawToChar(memory$get(1:11))
#> [1] "Hello_world"

Imports

set.seed(42)
imports <- list(
  env = list(
    add = typed_function(
      function(a, b) {
        # use R's RNG to add a random number to the result
        a + b * as.integer(runif(1) * 100)
      },
      param_types = c("I32", "I32"),
      return_type = "I32"
    )
  )
)
f <- system.file("examples/sum_import.wasm", package = "wasmr")
instance <- instantiate(f, imports)
# sum: add(a, b) + 42
instance$exports$sum(1, 5)
#> [1] 498

Caveats and limitations

• It is not feature complete and does not support everything that wasm supports
• Imported functions can only have integer parameters
• No globals
• There is hardly any documentation except for the examples
• I32/I64 are mapped to IntegerVector and F32/F64 to NumericVector. Currently no way to differentiate.
• WIP

Inspiration and References

• wasmer Python - haven’t tried it but looked at the API/examples
• wasmer - especially the C api and the tests give some good examples.
• @jeroen ’s rust template

Contribute

While this is work in progress, the best way to contribute is to test the package and write/comment on issues. Before sending a PR it would great to post an issue first to discuss.

License

MIT just like wasmer.

wasmr's Issues

configure - brew install rust

I think the command for MacOS is brew install rust. This just worked for me, where as rustc failed.

Fix travis

There seems to be a problem installing the package on linux...

Move to GitHub Actions

Fix travis

The rust compiler is a bit old so the compilation fails ATM

Update to 1.0.1

I have to wait for a fix in libffi to further develop it on my Mac m1

Update wasmer?

I cannot build it now on macOS with the latest (rustup update) tools:

error[E0425]: cannot find function `get_fault_info` in this scope
   --> /Users/gaborcsardi/.cargo/registry/src/github.com-1ecc6299db9ec823/wasmer-runtime-core-0.17.1/src/fault.rs:289:21
    |
289 |         let fault = get_fault_info(siginfo as _, ucontext);
    |                     ^^^^^^^^^^^^^^ not found in this scope

updating the wasmer version to 0.17.1 does not help, either.

Do you think it is possible to move to the new wasmer crate?

Build programmable array views

Similiar to the python wrapper. It should also support writes, but I think I need to write some rust for that first.

Package name: wasmrrr or wasmr?

Hi,

In the README the package is mentioned as dirkschumacher/wasmr, however the project url is dirkschumacher/wasmrrr.

It would be a good idea to standardize into only one name (rename the repo, or fix the README)