[rust] Add BUILD.md

rust/BUILD.md

@@ -0,0 +1,41 @@
+# Building and testing the Rust bindings
+
+These instructions require cargo and rustc.
+To get these follow the instructions at [https://rustup.rs](https://rustup.rs)
+The instructions compile the onnxruntime along with the bindings,
+so require `cmake`, a python 3 interpreter and gcc c++ compiler.
+
+## Local setup of onnxruntime repo
+
+```sh
+    git clone https://github.com/microsoft/onnxruntime
+    cd onnxruntime
+    git submodule update --init --recursive
+```
+
+## cargo build both crates
+
+from the root of onnxruntime repo
+
+```sh
+    CARGO_TARGET_DIR=build/rust cargo build --manifest-dir rust/Cargo.toml
+```
+
+The CARGO_TARGET_DIR environment variable puts the build artifacts in `onnxruntime/build/rust`
+instead of `onnxruntime/rust/target`.
+
+## cargo test both crates
+
+```sh
+    CARGO_TARGET_DIR=build/rust cargo test --manifest-dir rust/Cargo.toml --features model-fetching
+```
+
+## cargo test with sanitizer support
+
+**If you are using a nightly Rust compiler and are on one the platforms listed in [Rust sanitizer support](https://doc.rust-lang.org/beta/unstable-book/compiler-flags/sanitizer.html).**
+
+where `$SAN` is one of `address`, `thread`, `memory` or `leak`
+
+```sh
+    RUSTFLAGS="-Zsanitizer=$SAN" CARGO_TARGET_DIR=build/rust cargo test --manifest-dir rust/Cargo.toml --features model-fetching --target <your target for example x86_64-unknown-linux-gnu> -Z build-std -- --test-threads=1
+```