gecko-dev/third_party/rust/lucet-wasi-wasmsbx/examples

WASI Examples

These are some examples showing how to build and run WASI programs with the Lucet runtime. By default, the Makefile in this directory builds and runs a Hello World program, but see below for other examples.

By default, these examples look for the WASI SDK to be installed in /opt/wasi-sdk, which is present in the Lucet devenv environment. If you want to use your own SDK, you can override the environment variables WASI_CC and WASI_LD with paths to your own clang and wasm-ld.

Hello World

In addition to the standard Hello World behavior, this program also shows the use of command-line arguments and environment variables:

cargo run -p lucet-wasi -- ./build/hello.so
   Compiling lucet-wasi v0.1.0 (/lucet/lucet-wasi)
    Finished dev [unoptimized + debuginfo] target(s) in 1.91s
     Running `/lucet/target/debug/lucet-wasi ./build/hello.so`
hello, wasi!

cargo run -p lucet-wasi -- ./build/hello.so -- "readme reader"
    Finished dev [unoptimized + debuginfo] target(s) in 0.10s
     Running `/lucet/target/debug/lucet-wasi ./build/hello.so -- 'readme reader'`
hello, readme reader!

GREETING="goodbye" cargo run -p lucet-wasi -- ./build/hello.so -- "readme reader"
    Finished dev [unoptimized + debuginfo] target(s) in 0.11s
     Running `/lucet/target/debug/lucet-wasi ./build/hello.so -- 'readme reader'`
goodbye, readme reader!

Use the make run-hello or make run-hello-all targets to run these variations.

KGT

This example shows that a realistically-sized program, using standard IO and command-line arguments, can be compiled against WASI with no modifications to its source. In addition to the WASI SDK requirements mentioned above, the kgt example requires pmake to be installed:

# make run-kgt
cargo run -p lucet-wasi -- ./build/kgt.so -- -l bnf -e rrutf8 < build/kgt/examples/expr.bnf
    Finished dev [unoptimized + debuginfo] target(s) in 0.12s
     Running `/lucet/target/debug/lucet-wasi ./build/kgt.so -- -l bnf -e rrutf8`
expr:
    │├──╮── term ── "+" ── expr ──╭──┤│
        │                         │
        ╰───────── term ──────────╯

term:
    │├──╮── factor ── "*" ── term ──╭──┤│
        │                           │
        ╰───────── factor ──────────╯

factor:
    │├──╮── "(" ── expr ── ")" ──╭──┤│
        │                        │
        ╰──────── const ─────────╯

const:
    │├── integer ──┤│