IREE "Static Library" sample

This sample shows how to:

1. Produce a static library and bytecode module with IREE's compiler
2. Compile the static library into a program using the static_library_loader
3. Run the demo with the module using functions exported by the static library

The model compiled into the static library exports a single function simple_mul that returns the multiplication of two tensors:

func.func @simple_mul(%arg0: tensor<4xf32>, %arg1: tensor<4xf32>) -> tensor<4xf32> {
  %0 = "arith.mulf"(%arg0, %arg1) : (tensor<4xf32>, tensor<4xf32>) -> tensor<4xf32>
  return %0 : tensor<4xf32>
}

Background

IREE's static_library_loader allows applications to inject a set of static libraries that can be resolved at runtime by name. This can be particularly useful on "bare metal" or embedded systems running IREE that lack operating systems or the ability to load shared libraries in binaries.

When static library output is enabled, iree-compile produces a separate static library to compile into the target program. At runtime bytecode module instructs the VM which static libraries to load exported functions from the model.

Instructions

Note: run the following commands from IREE's github repo root.

1. Configure CMake for building the static library then demo. You'll need to set the flags building samples, the compiler, the llvm-cpu compiler target backend, and the local-sync runtime HAL driver (see the getting started guide for general instructions on building using CMake):

cmake -B ../iree-build/ -G Ninja \
  -DCMAKE_BUILD_TYPE=RelWithDebInfo .
  -DIREE_BUILD_SAMPLES=ON \
  -DIREE_TARGET_BACKEND_DEFAULTS=OFF \
  -DIREE_TARGET_BACKEND_LLVM_CPU=ON \
  -DIREE_HAL_DRIVER_DEFAULTS=OFF \
  -DIREE_HAL_DRIVER_LOCAL_SYNC=ON \
  -DIREE_HAL_EXECUTABLE_LOADER_DEFAULTS=OFF \
  -DIREE_HAL_EXECUTABLE_PLUGIN_DEFAULTS=OFF \
  -DIREE_BUILD_COMPILER=ON \

2. Build the static_library_demo CMake target to create the static demo. This target has several dependencies that will compile simple_mul.mlir into a static library (simple_mul.h & simple_mul.c) as well as a bytecode module (simple_mul.vmfb) which are finally built into the demo binary:

cmake --build ../iree-build/ --target iree_samples_static_library_static_library_demo

3. Run the sample binary:

../iree-build/samples/static_library/static_library_demo

# Output: static_library_run_bytecode passed

Changing compilation options

The steps above build both the compiler for the host (machine doing the compiling) and the demo for the target using same options as the host machine. If you wish to target a different platform other than the host, you'll need to compile the library and demo with different options.

For example, see this documentation on cross compiling on Android.

Note: separating the target from the host will require modifying dependencies in the demos CMakeLists.txt. See included comments for more info.