A compatible LLVM needs to be built for RISC-V, it also needs LLD built. See version of LLVM. We suggest building with:

$ cd <llvm repo dir>
$ mkdir build
$ cd build
$ cmake -GNinja \
    -DLLVM_TARGETS_TO_BUILD="RISCV" \
    -DCMAKE_INSTALL_PREFIX=$LLVM_INSTALL_DIR \
    -DLLVM_ENABLE_PROJECTS='clang;lld' \
    -DLLVM_ENABLE_ASSERTIONS=On \
    -DCMAKE_BUILD_TYPE=Release \
    -DLLVM_INSTALL_UTILS=ON \
    ../llvm
$ ninja install

To build we first of all need to create a build directory inside your top level directory. Firstly we set up the CMake directive.

$ mkdir build
$ export LLVM_INSTALL_DIR=<your_llvm_install_dir>
$ export ONEAPI_CON_KIT_PATH=<your_oneapi_construction_kit_dir>
$ cmake -GNinja -DCA_MUX_TARGETS_TO_ENABLE="refsi_tutorial" \
    -DCA_REFSI_TUTORIAL_ENABLED=ON -DCA_ENABLE_API=cl \
    -DCMAKE_BUILD_TYPE=Debug \
    -DCA_LLVM_INSTALL_DIR=$LLVM_INSTALL_DIR \
    -DCA_ENABLE_DEBUG_SUPPORT=ON \
    -DCA_ENABLE_OFFLINE_LIBRARIES=OFF -DCA_ENABLE_HOST_IMAGE_SUPPORT=OFF \
    -DCA_CL_ENABLE_OFFLINE_KERNEL_TESTS=OFF \
    -DCA_EXTERNAL_ONEAPI_CON_KIT_DIR=$ONEAPI_CON_KIT_PATH \
    -DCA_EXTERNAL_REFSI_TUTORIAL_HAL_DIR=<path to target hal> \
    -Bbuild .

The CA_MUX_TARGETS_TO_ENABLE should match the target_name field from the JSON file.

Now we build the UnitCL test target, which will also build all its dependencies, including the oneAPI Construction Kit and the new target:

$ cd build/oneAPIConstructionKit
$ ninja UnitCL

We can do a quick test, using the environment variable REFSI_DEBUG for more information:

$ REFSI_DEBUG=1 ./bin/UnitCL --gtest_filter=Execution/Execution.Task_01_02_Add/OpenCLC

You should see something similar to this:

Note: Google Test filter = Execution/Execution.Task_01_02_Add/OpenCLC
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from Execution/Execution
[ RUN      ] Execution/Execution.Task_01_02_Add/OpenCLC
[CMP] Starting.
[CMP] Starting to execute command buffer at 0x47fff1a0.
[CMP] CMP_WRITE_REG64(ENTRY_PT_FN, 0x10000)
[CMP] CMP_WRITE_REG64(KUB_DESC, 0x20000bff0f200)
[CMP] CMP_WRITE_REG64(KARGS_INFO, 0x0)
[CMP] CMP_WRITE_REG64(TSD_INFO, 0x1280000200000)
[CMP] CMP_RUN_KERNEL_SLICE(n=4, slice_id=0, max_harts=0)
[CMP] CMP_FINISH
[CMP] Finished executing command buffer.
../modules/kts/include/kts/execution_shared.h:16: Failure
Invalid data when validating buffer 2:
Result mismatch at index 64 (expected: 512, actual: 0)
[  FAILED  ] Execution/Execution.Task_01_02_Add/OpenCLC, where GetParam() = 0 (48 ms)

Although this runs, it actually returns a failure. This is because the compiler pipeline is creating an executable for the kernel with a defined interface. This interface does not match that expected for a kernel running in the RefSi architecture. We can resolve this by adding an additional pass to translate between what RefSi kernels expect and what the default pipeline does. This is shown in the next section.