[libclc] Add initial support for libclc execution conformance tests (#214072) Summary: This uses the `llvm-gpu-loader` tool to invoke OpenCL test kernels. This routes OpenCL through the standard compute runtimes, which aren't exactly 1-to-1 with OpenCL, but it's close enough. Obviously, the best solution would be to have a real OpenCL host library that can launch these, but this is the best we can get in-tree and is very sipmle, write kernel, test kernel. The goal is to have a lot more tests run here, but this just gets the basic infrastructure in place. We won't be able to do full conformance like external suites, like exhaustive math, but I think its' a step in the right direction. It looks like this on my side: ```console $ ninja check-libclc-amdgpu-amd-amdhsa-llvm ``` This requires building with the LLVM `offload/` runtime enabled for the source compiler. GitOrigin-RevId: d87c685d5d88fe00b0594fc238b9afb16ba6eb64
libclc is an open source implementation of the library requirements of the OpenCL C programming language, as specified by the OpenCL 1.1 Specification. The following sections of the specification impose library requirements:
libclc is intended to be used with the Clang compiler's OpenCL frontend.
libclc is designed to be portable and extensible. To this end, it provides generic implementations of most library requirements, allowing the target to override the generic implementation at the granularity of individual functions.
libclc currently supports PTX, AMDGPU, SPIRV and CLSPV targets, but support for more targets is welcome.
libclc is built as part of an LLVM runtimes build.
Select the targets to build with LLVM_RUNTIME_TARGETS, and enable libclc for each selected target with the matching RUNTIMES_<target-triple>_LLVM_ENABLE_RUNTIMES cache entry.
cd llvm-project mkdir build cd build cmake ../llvm -G Ninja -DLLVM_ENABLE_PROJECTS="clang" -DCMAKE_BUILD_TYPE=Release \ -DRUNTIMES_amdgcn-amd-amdhsa-llvm_LLVM_ENABLE_RUNTIMES=libclc \ -DLLVM_RUNTIME_TARGETS="amdgcn-amd-amdhsa-llvm"
cmake ../llvm -G Ninja -DLLVM_ENABLE_PROJECTS="clang" -DCMAKE_BUILD_TYPE=Release \ -DRUNTIMES_nvptx64-nvidia-cuda_LLVM_ENABLE_RUNTIMES=libclc \ -DLLVM_RUNTIME_TARGETS="nvptx64-nvidia-cuda"
cmake ../llvm -G Ninja -DLLVM_ENABLE_PROJECTS="clang" -DCMAKE_BUILD_TYPE=Release \ -DRUNTIMES_spirv64-unknown-vulkan_LLVM_ENABLE_RUNTIMES=libclc \ -DLLVM_RUNTIME_TARGETS="spirv64-unknown-vulkan"
cmake ../llvm -G Ninja -DLLVM_ENABLE_PROJECTS="clang" -DCMAKE_BUILD_TYPE=Release \ -DRUNTIMES_spirv32-unknown-unknown_LLVM_ENABLE_RUNTIMES=libclc \ -DRUNTIMES_spirv64-unknown-unknown_LLVM_ENABLE_RUNTIMES=libclc \ -DLLVM_RUNTIME_TARGETS="spirv32-unknown-unknown;spirv64-unknown-unknown"
To build multiple targets, pass them as a semicolon-separated list in LLVM_RUNTIME_TARGETS and provide a matching RUNTIMES_<target-triple>_LLVM_ENABLE_RUNTIMES=libclc entry for each target.
ninja
ninja install
Note you can use the DESTDIR Makefile variable to do staged installs.
DESTDIR=/path/for/staged/install ninja install
libclc utilizes the LLVM testing infrastructure.
To execute all per-target tests for libclc.
ninja check-libclc
check-libclc is a top-level target that aggregates all per-target tests.
If you are working on a specific target, you can run tests for just that target triple:
ninja check-libclc-<target-triple>
Alternatively, you can run target-specific tests via the runtimes build by pointing to the target-specific build directory:
ninja -C runtimes/runtimes-<target-triple>-bins check-libclc
To build out of tree, or in other words, against an existing LLVM build or install:
CC=$(<path-to>/llvm-config --bindir)/clang cmake \ <path-to>/llvm-project/libclc/CMakeLists.txt -DCMAKE_BUILD_TYPE=Release \ -G Ninja -DLLVM_DIR=$(<path-to>/llvm-config --cmakedir) \ -DLLVM_RUNTIMES_TARGET=<target-triple> $ ninja
Then install as before.
In both cases, the LLVM used must include the targets you want libclc support for (AMDGPU and NVPTX are enabled in LLVM by default). Apart from SPIRV where you do not need an LLVM target but you do need the llvm-spirv tool available. Either build this in-tree, or place it in the directory pointed to by LLVM_TOOLS_BINARY_DIR.