runanywhere_qhexrt

Private QHexRT backend for the RunAnywhere Flutter SDK — runs prebuilt QNN context binaries on Qualcomm Snapdragon Hexagon NPUs (v75+), serving LLM, VLM, STT and TTS through the standard SDK APIs.

Android only, arm64-v8a only. On parts older than v75, the backend declines to register and inference stays disabled (NPU-only — no CPU fallback in this package).

Usage

import 'package:runanywhere/runanywhere.dart';
import 'package:runanywhere_qhexrt/runanywhere_qhexrt.dart';

await RunAnywhere.initialize();

final npu = QHexRT.probeNpu();      // pre-flight, no QNN load
if (npu.qhexrtSupported) {          // generated runanywhere.v1.NpuCapability
  await QHexRT.register();          // registers the QHexRT engine
}

probeNpu() returns the generated runanywhere.v1.NpuCapability proto message (socModel, socId, hexagonArch, qhexrtSupported, archName), decoded from commons' rac_npu_probe_proto() — no hand-mirrored types.

Native libraries

The private QHexRT natives are staged, not committed: the android/src/main/jniLibs/arm64-v8a/ directory is gitignored and must be populated before a real (non-stub) build:

scripts/stage-natives.sh --natives-from /path/to/android-libs

The script copies librac_backend_qhexrt*.so (QHexRT engine), the QAIRT runtime/skel set (libQnnHtp*.so, libQnnSystem.so, per-arch v75/v79/v81 Skel/Stub/CalculatorStub) and libc++_shared.so — the same set the React Native package-sdk.sh stages for its qhexrt package. librac_commons.so is provided by the core runanywhere plugin.

Building without staged natives is allowed (the Gradle build prints a warning): the plugin then behaves as a stub and reports the NPU as unavailable at runtime.