Add an initial wasi-nn implementation for Wasmtime (#2208)

* Add an initial wasi-nn implementation for Wasmtime

This change adds a crate, `wasmtime-wasi-nn`, that uses `wiggle` to expose the current state of the wasi-nn API and `openvino` to implement the exposed functions. It includes an end-to-end test demonstrating how to do classification using wasi-nn:
 - `crates/wasi-nn/tests/classification-example` contains Rust code that is compiled to the `wasm32-wasi` target and run with a Wasmtime embedding that exposes the wasi-nn calls
 - the example uses Rust bindings for wasi-nn contained in `crates/wasi-nn/tests/wasi-nn-rust-bindings`; this crate contains code generated by `witx-bindgen` and eventually should be its own standalone crate

* Test wasi-nn as a CI step

This change adds:
 - a GitHub action for installing OpenVINO
 - a script, `ci/run-wasi-nn-example.sh`, to run the classification example

Cargo.lock

@@ -128,6 +128,30 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "bindgen"
+version = "0.55.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "75b13ce559e6433d360c26305643803cb52cfbabbc2b9c47ce04a58493dfb443"
+dependencies = [
+ "bitflags",
+ "cexpr",
+ "cfg-if 0.1.10",
+ "clang-sys",
+ "clap",
+ "env_logger 0.7.1",
+ "lazy_static",
+ "lazycell",
+ "log",
+ "peeking_take_while",
+ "proc-macro2",
+ "quote",
+ "regex",
+ "rustc-hash",
+ "shlex",
+ "which",
+]
+
 [[package]]
 name = "bit-set"
 version = "0.5.2"
@@ -210,6 +234,15 @@ dependencies = [
  "jobserver",
 ]
 
+[[package]]
+name = "cexpr"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f4aedb84272dbe89af497cf81375129abda4fc0a9e7c5d317498c15cc30c0d27"
+dependencies = [
+ "nom",
+]
+
 [[package]]
 name = "cfg-if"
 version = "0.1.10"
@@ -235,6 +268,17 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "clang-sys"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9da1484c6a890e374ca5086062d4847e0a2c1e5eba9afa5d48c09e8eb39b2519"
+dependencies = [
+ "glob",
+ "libc",
+ "libloading",
+]
+
 [[package]]
 name = "clap"
 version = "2.33.3"
@@ -1048,6 +1092,12 @@ version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
+[[package]]
+name = "lazycell"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b294d6fa9ee409a054354afc4352b0b9ef7ca222c69b8812cbea9e7d2bf3783f"
+
 [[package]]
 name = "leb128"
 version = "0.2.4"
@@ -1070,6 +1120,16 @@ dependencies = [
  "cc",
 ]
 
+[[package]]
+name = "libloading"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2443d8f0478b16759158b2f66d525991a05491138bc05814ef52a250148ef4f9"
+dependencies = [
+ "cfg-if 0.1.10",
+ "winapi",
+]
+
 [[package]]
 name = "lightbeam"
 version = "0.21.0"
@@ -1184,6 +1244,16 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0debeb9fcf88823ea64d64e4a815ab1643f33127d995978e099942ce38f25238"
 
+[[package]]
+name = "nom"
+version = "5.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ffb4262d26ed83a1c0a33a38fe2bb15797329c85770da05e6b828ddb782627af"
+dependencies = [
+ "memchr",
+ "version_check",
+]
+
 [[package]]
 name = "num-integer"
 version = "0.1.44"
@@ -1242,6 +1312,26 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "624a8340c38c1b80fd549087862da4ba43e08858af025b236e509b6649fc13d5"
 
+[[package]]
+name = "openvino"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87a74f90f07f134153e3ad2ffa724a3ebda92cdc6e099f7fe7d9185cf960f028"
+dependencies = [
+ "openvino-sys",
+ "thiserror",
+]
+
+[[package]]
+name = "openvino-sys"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e72a2e5bd353bd3cf39b2663767e0ae0325a7588c47fd496cbf9a09237ef7ca8"
+dependencies = [
+ "bindgen",
+ "cmake",
+]
+
 [[package]]
 name = "os_pipe"
 version = "0.9.2"
@@ -1252,6 +1342,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "peeking_take_while"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "19b17cddbe7ec3f8bc800887bab5e717348c95ea2ca0b1bf0837fb964dc67099"
+
 [[package]]
 name = "peepmatic"
 version = "0.68.0"
@@ -1828,6 +1924,12 @@ dependencies = [
  "dirs",
 ]
 
+[[package]]
+name = "shlex"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7fdf1b9db47230893d76faad238fd6097fd6d6a9245cd7a4d90dbd639536bbd2"
+
 [[package]]
 name = "smallvec"
 version = "1.4.2"
@@ -2344,6 +2446,7 @@ dependencies = [
  "wasmtime-obj",
  "wasmtime-runtime",
  "wasmtime-wasi",
+ "wasmtime-wasi-nn",
  "wasmtime-wast",
  "wat",
 ]
@@ -2547,6 +2650,21 @@ dependencies = [
  "wiggle",
 ]
 
+[[package]]
+name = "wasmtime-wasi-nn"
+version = "0.21.0"
+dependencies = [
+ "anyhow",
+ "log",
+ "openvino",
+ "thiserror",
+ "wasmtime",
+ "wasmtime-runtime",
+ "wasmtime-wasi",
+ "wasmtime-wiggle",
+ "wiggle",
+]
+
 [[package]]
 name = "wasmtime-wast"
 version = "0.21.0"
@@ -2604,6 +2722,15 @@ dependencies = [
  "wast 27.0.0",
 ]
 
+[[package]]
+name = "which"
+version = "3.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d011071ae14a2f6671d0b74080ae0cd8ebf3a6f8c9589a2cd45f23126fe29724"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "wig"
 version = "0.21.0"