hiai-rs

Rust bindings for Huawei Ascend NPUs using the HiAI (CANN) DDK on OpenHarmony — build and run neural-network graphs.

EXPERIMENTAL — NOT FOR PRODUCTION USE. The API is unstable and will change.

Workspace layout

Crate	Purpose
hiai-rs-sys	Raw, unsafe FFI bindings to the HiAI DDK (bindgen-generated). Internal use only.
hiai-rs	Safe Rust wrapper: TensorDesc + dispatch() for running prebuilt models.

What it wraps

The HiAI DDK is Huawei's libhiai runtime (part of the CANN stack) for OpenHarmony devices with Ascend NPUs. This crate binds a thin pure-C adapter (hiai-rs-sys/adapter/) that wraps the DDK's C++ API (hiai::op::*, the GE graph engine, and the model manager) so it can be called from Rust.

• Graph build (WebNN → CANN IR) lives in rustnn; this crate only binds the low-level FFI and model dispatch.
• The adapter is compiled and libhiai is linked only when cross-compiling for OpenHarmony (aarch64-unknown-linux-ohos).

Building

Host (bindgen smoke test — no DDK required)

The adapter's public headers are self-contained, so bindgen runs on any host:

cargo build

OpenHarmony device (full build + link)

Requires the Huawei CANN-Kit DDK and the OpenHarmony SDK, plus the OHOS target:

export CANN_DDK=/path/to/CANN-Kit-next/ddk/
export OHOS_SDK_NATIVE=/path/to/OpenHarmony/sdk/native
cargo build --target aarch64-unknown-linux-ohos --release

Usage

use hiai_rs::{TensorDesc, dispatch};

// Prebuilt offline model bytes (produced by the rustnn CANN converter).
let model_bytes: &[u8] = todo!();

let inputs = vec![TensorDesc {
    data: vec![1.0f32; 4].into_iter().flat_map(|v| v.to_le_bytes()).collect(),
    shape: vec![1, 4],
    dtype: 0, // CANN_DT_FLOAT
}];

let mut outputs = vec![TensorDesc {
    data: vec![0u8; 16],
    shape: vec![1, 4],
    dtype: 0,
}];

dispatch(model_bytes, &inputs, &mut outputs)?;
# Ok::<(), hiai_rs::Error>(())

Environment variables

• CANN_DDK — path to the Huawei CANN-Kit DDK (required for OpenHarmony builds).
• OHOS_SDK_NATIVE — path to the OpenHarmony SDK native toolchain (for the aarch64-unknown-linux-ohos target).

Attribution

The C++ adapter under hiai-rs-sys/adapter/ is a local pure-C shim over the HiAI DDK. It is licensed under Apache-2.0 (see each file's SPDX header).

License

Apache-2.0. See LICENSE.