Google Git
Sign in
llvm/llvm-project/libclc/d309d31a8dd222d83bd0242cc4d3846d7e1b88a3
commit
d309d31a8dd222d83bd0242cc4d3846d7e1b88a3
[log]
author
Wenju He <wenju.he@intel.com>
Mon Apr 13 08:19:08 2026 +0800
committer
Copybara-Service <copybara-worker@google.com>
Sun Apr 12 17:20:45 2026 -0700
tree
fbb422a7cfa04f03f02aebd61ef81b85287b0403
parent
13d7a2f99f64aadbe4c0f2db600c08d174ea0d8a [diff]
[libclc] Enable LLVM_RUNTIME_TARGETS in build system (#189892)

libclc target is now passed in from LLVM_RUNTIME_TARGETS.

The old configure flow based on `-DLLVM_ENABLE_RUNTIMES=libclc` is
deprecated because libclc no longer has a default target.
`-DLLVM_ENABLE_RUNTIMES=libclc -DLLVM_RUNTIME_TARGETS="<target-triple>"`
still works but it is considered legacy.

The new standard build requires:
Each target must now be selected explicitly on the CMake command line
through the runtimes target-specific cache entry and
LLVM_RUNTIME_TARGETS.
For example:
-DRUNTIMES_amdgcn-amd-amdhsa-llvm_LLVM_ENABLE_RUNTIMES=libclc
-DLLVM_RUNTIME_TARGETS="amdgcn-amd-amdhsa-llvm"
-DRUNTIMES_nvptx64-nvidia-cuda_LLVM_ENABLE_RUNTIMES=libclc
-DLLVM_RUNTIME_TARGETS="nvptx64-nvidia-cuda"
-DRUNTIMES_clspv--_LLVM_ENABLE_RUNTIMES=libclc
-DLLVM_RUNTIME_TARGETS="clspv--"
-DRUNTIMES_clspv64--_LLVM_ENABLE_RUNTIMES=libclc
-DLLVM_RUNTIME_TARGETS="clspv64--"
-DRUNTIMES_spirv-mesa3d-_LLVM_ENABLE_RUNTIMES=libclc
-DLLVM_RUNTIME_TARGETS="spirv-mesa3d-"
-DRUNTIMES_spirv64-mesa3d-_LLVM_ENABLE_RUNTIMES=libclc
-DLLVM_RUNTIME_TARGETS="spirv64-mesa3d-"

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.

Updated README.md to document the new build flow.

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
GitOrigin-RevId: 121f5a96ff38ec0c5d5f7274b1b0ca0df26a1cee
3 files changed
tree: fbb422a7cfa04f03f02aebd61ef81b85287b0403
  1. clc/
  2. cmake/
  3. opencl/
  4. test/
  5. www/
  6. CMakeLists.txt
  7. compile-test.sh
  8. CREDITS.TXT
  9. LICENSE.TXT
  10. Maintainers.md
  11. README.md
README.md

libclc

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:

  • 6.1: Supported Data Types
  • 6.2.3: Explicit Conversions
  • 6.2.4.2: Reinterpreting Types Using as_type() and as_typen()
  • 6.9: Preprocessor Directives and Macros
  • 6.11: Built-in Functions
  • 9.3: Double Precision Floating-Point
  • 9.4: 64-bit Atomics
  • 9.5: Writing to 3D image memory objects
  • 9.6: Half Precision Floating-Point

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.

Configure, build, and install

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.

Configure for the AMDGPU target

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"

Configure for the NVPTX64 target

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"

Configure for CLSPV targets

cmake ../llvm -G Ninja -DLLVM_ENABLE_PROJECTS="clang" -DCMAKE_BUILD_TYPE=Release \
  -DRUNTIMES_clspv--_LLVM_ENABLE_RUNTIMES=libclc \
  -DRUNTIMES_clspv64--_LLVM_ENABLE_RUNTIMES=libclc \
  -DLLVM_RUNTIME_TARGETS="clspv--;clspv64--"

Configure for SPIR-V targets

cmake ../llvm -G Ninja -DLLVM_ENABLE_PROJECTS="clang" -DCMAKE_BUILD_TYPE=Release \
  -DRUNTIMES_spirv-mesa3d-_LLVM_ENABLE_RUNTIMES=libclc \
  -DRUNTIMES_spirv64-mesa3d-_LLVM_ENABLE_RUNTIMES=libclc \
  -DLLVM_RUNTIME_TARGETS="spirv-mesa3d-;spirv64-mesa3d-"

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.

Build

ninja

Install

ninja install

Note you can use the DESTDIR Makefile variable to do staged installs.

DESTDIR=/path/for/staged/install ninja install

Run tests

ninja check-libclc-<target-triple>

or

ninja -C runtimes/runtimes-<target-triple>-bins check-libclc

Out-of-tree build

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.

Website

https://libclc.llvm.org/