[llvm] [SYCL] Add RT dependency on interface layer for offloading (PR #161195)
Kseniya Tikhomirova via llvm-commits
llvm-commits at lists.llvm.org
Mon Oct 6 06:43:01 PDT 2025
https://github.com/KseniyaTikhomirova updated https://github.com/llvm/llvm-project/pull/161195
>From e742c7def02d94604b27bdec40e8d69aa5986e9e Mon Sep 17 00:00:00 2001
From: "Tikhomirova, Kseniya" <kseniya.tikhomirova at intel.com>
Date: Fri, 11 Jul 2025 04:24:40 -0700
Subject: [PATCH] [SYCL] Add dependency on interface layer for offloading
The SYCL runtime is device-agnostic and uses Unified Runtime (GitHub -
oneapi-src/unified-runtime) as an external dependency. This Unified Runtime
serves as an interface layer between the SYCL runtime and device-specific
backends. Unified Runtime has several adapters that bind to various backends.
NOTE: UR is considered as temporal solution until llvm-project/offload is
fully functional and is able to replace UR.
Signed-off-by: Tikhomirova, Kseniya <kseniya.tikhomirova at intel.com>
---
.github/workflows/libsycl-build-and-test.yaml | 39 ++++++
libsycl/CMakeLists.txt | 14 ++
.../cmake/Modules/FetchUnifiedRuntime.cmake | 122 ++++++++++++++++++
libsycl/docs/DesignDocs/UnifiedRuntime.rst | 23 ++++
libsycl/src/CMakeLists.txt | 14 +-
5 files changed, 207 insertions(+), 5 deletions(-)
create mode 100644 .github/workflows/libsycl-build-and-test.yaml
create mode 100644 libsycl/cmake/Modules/FetchUnifiedRuntime.cmake
create mode 100644 libsycl/docs/DesignDocs/UnifiedRuntime.rst
diff --git a/.github/workflows/libsycl-build-and-test.yaml b/.github/workflows/libsycl-build-and-test.yaml
new file mode 100644
index 0000000000000..548b3d3a8e5f3
--- /dev/null
+++ b/.github/workflows/libsycl-build-and-test.yaml
@@ -0,0 +1,39 @@
+# This file defines pre-commit CI for libsycl++.
+name: Build libsycl
+on:
+ pull_request:
+ paths:
+ - 'libsycl/**'
+ - '.github/workflows/libsycl-build-and-test.yaml'
+
+permissions:
+ contents: read # Default everything to read-only
+
+concurrency:
+ # Cancel a currently running workflow from the same PR
+ group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
+ cancel-in-progress: true
+
+jobs:
+ build_ubuntu2204:
+ # sergey-semenov repo is set is for test purposes
+ if: github.repository_owner == 'sergey-semenov'
+ # github runner
+ runs-on: ubuntu-22.04
+ # reuse libcxx container for now
+ container: ghcr.io/llvm/libcxx-linux-builder:2b57ebb50b6d418e70382e655feaa619b558e254
+ continue-on-error: false
+ steps:
+ - uses: actions/checkout at v4
+ - name: Compile
+ env:
+ CC: 'clang-21'
+ CXX: 'clang++-21'
+ run: |
+ mkdir -p $GITHUB_WORKSPACE/build
+ mkdir -p $GITHUB_WORKSPACE/install
+ cmake -G Ninja -S $GITHUB_WORKSPACE/runtimes -B $GITHUB_WORKSPACE/build \
+ -DCMAKE_INSTALL_PREFIX=$GITHUB_WORKSPACE/install \
+ -DLLVM_ENABLE_RUNTIMES="libsycl" \
+ -DCMAKE_BUILD_TYPE=Release
+ ninja -C $GITHUB_WORKSPACE/build install --verbose
diff --git a/libsycl/CMakeLists.txt b/libsycl/CMakeLists.txt
index fe08a4249bada..2d35378b56426 100644
--- a/libsycl/CMakeLists.txt
+++ b/libsycl/CMakeLists.txt
@@ -31,6 +31,12 @@ endif()
option(LIBSYCL_ENABLE_WERROR "Treat all warnings as errors in the libsycl project" OFF)
option(LIBSYCL_ENABLE_PEDANTIC "Compile with pedantic enabled." OFF)
+# If LIBSYCL_ENABLE_BACKENDS is undefined, we default to enabling OpenCL and Level
+# Zero backends.
+if (NOT DEFINED LIBSYCL_ENABLE_BACKENDS)
+ set(LIBSYCL_ENABLE_BACKENDS "opencl;level_zero" CACHE STRING "Backends enabled for SYCL")
+endif()
+
#===============================================================================
# Configure System
#===============================================================================
@@ -77,6 +83,14 @@ if (NOT LIBSYCL_ABI_NAMESPACE MATCHES "__V.*")
message(FATAL_ERROR "LIBSYCL_ABI_NAMESPACE must be a reserved identifier, got '${LIBSYCL_ABI_NAMESPACE}'.")
endif()
+#===============================================================================
+# Dependencies
+#===============================================================================
+
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules")
+# Download & build dependency for kernel offloading
+include(FetchUnifiedRuntime)
+
#===============================================================================
# Setup build & install rules
#===============================================================================
diff --git a/libsycl/cmake/Modules/FetchUnifiedRuntime.cmake b/libsycl/cmake/Modules/FetchUnifiedRuntime.cmake
new file mode 100644
index 0000000000000..b3ddc2f3a212f
--- /dev/null
+++ b/libsycl/cmake/Modules/FetchUnifiedRuntime.cmake
@@ -0,0 +1,122 @@
+#===============================================================================
+# Fetches Unified Runtime used by SYCL language runtime to abstract SYCL open
+# standard and vendor heterogeneous offload interfaces.
+#
+# This will in time be replaced by the new LLVM Offload interface.
+#
+# Unified Runtime is Apache 2.0 license with LLVM exceptions.
+#
+#===============================================================================
+
+option(LIBSYCL_UR_BUILD_TESTS "Build tests for UR" OFF)
+
+set(UR_BUILD_TESTS "${LIBSYCL_UR_BUILD_TESTS}" CACHE BOOL "" FORCE)
+# UR tests require the examples to be built
+set(UR_BUILD_EXAMPLES "${LIBSYCL_UR_BUILD_TESTS}" CACHE BOOL "" FORCE)
+
+if("level_zero" IN_LIST LIBSYCL_ENABLE_BACKENDS)
+ set(UR_BUILD_ADAPTER_L0 ON)
+endif()
+if("cuda" IN_LIST LIBSYCL_ENABLE_BACKENDS)
+ set(UR_BUILD_ADAPTER_CUDA ON)
+endif()
+if("hip" IN_LIST LIBSYCL_ENABLE_BACKENDS)
+ set(UR_BUILD_ADAPTER_HIP ON)
+endif()
+if("opencl" IN_LIST LIBSYCL_ENABLE_BACKENDS)
+ set(UR_BUILD_ADAPTER_OPENCL ON)
+endif()
+
+# Disable errors from warnings while building the UR.
+# And remember the original flags before doing that.
+set(CMAKE_CXX_FLAGS_BAK "${CMAKE_CXX_FLAGS}")
+if(WIN32)
+ append("/WX-" CMAKE_CXX_FLAGS)
+ append("/WX-" CMAKE_C_FLAGS)
+ # Unified runtime build fails with /DUNICODE
+ append("/UUNICODE" CMAKE_CXX_FLAGS)
+ append("/UUNICODE" CMAKE_C_FLAGS)
+ append("/EHsc" CMAKE_CXX_FLAGS)
+ append("/EHsc" CMAKE_C_FLAGS)
+else()
+ append("-Wno-error" CMAKE_CXX_FLAGS)
+ append("-Wno-error" CMAKE_C_FLAGS)
+endif()
+
+if(NOT FETCHCONTENT_SOURCE_DIR_UNIFIED-RUNTIME)
+ find_package(unified-runtime)
+ if(unified-runtime_FOUND)
+ message (STATUS "Found system install of unified-runtime")
+ return()
+ endif()
+endif()
+
+include(FetchContent)
+
+set(UNIFIED_RUNTIME_REPO "https://github.com/oneapi-src/unified-runtime.git")
+set(UNIFIED_RUNTIME_TAG 8ee4da175c197d4dc5c9ec939e7e4d87d4edfa99)
+
+FetchContent_Declare(unified-runtime
+ GIT_REPOSITORY ${UNIFIED_RUNTIME_REPO}
+ GIT_TAG ${UNIFIED_RUNTIME_TAG}
+)
+
+FetchContent_GetProperties(unified-runtime)
+if(FETCHCONTENT_SOURCE_DIR_UNIFIED-RUNTIME)
+ message(STATUS "Using specified Unified Runtime repo location at ${FETCHCONTENT_SOURCE_DIR_UNIFIED-RUNTIME}")
+else()
+ message(STATUS "Cloning Unified Runtime from ${UNIFIED_RUNTIME_REPO}")
+endif()
+FetchContent_MakeAvailable(unified-runtime)
+
+set(UNIFIED_RUNTIME_SOURCE_DIR
+ "${unified-runtime_SOURCE_DIR}" CACHE PATH
+ "Path to Unified Runtime Headers" FORCE)
+
+set(UMF_BUILD_EXAMPLES OFF CACHE INTERNAL "UMF EXAMPLES")
+# Due to the use of dependentloadflag and no installer for UMF and hwloc we need
+# to link statically on windows
+if(WIN32)
+ set(UMF_BUILD_SHARED_LIBRARY OFF CACHE INTERNAL "Build UMF shared library")
+ set(UMF_LINK_HWLOC_STATICALLY ON CACHE INTERNAL "static HWLOC")
+endif()
+
+# Restore original flags
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS_BAK}")
+
+message(STATUS
+ "Using Unified Runtime source directory: ${UNIFIED_RUNTIME_SOURCE_DIR}")
+
+set(UNIFIED_RUNTIME_INCLUDE_DIR "${UNIFIED_RUNTIME_SOURCE_DIR}/include")
+set(UNIFIED_RUNTIME_SRC_INCLUDE_DIR "${UNIFIED_RUNTIME_SOURCE_DIR}/source")
+set(UNIFIED_RUNTIME_COMMON_INCLUDE_DIR "${UNIFIED_RUNTIME_SOURCE_DIR}/source/common")
+
+add_library(UnifiedRuntimeLoader ALIAS ur_loader)
+add_library(UnifiedRuntime-Headers INTERFACE)
+
+target_include_directories(UnifiedRuntime-Headers
+ INTERFACE
+ "${UNIFIED_RUNTIME_INCLUDE_DIR}"
+)
+
+add_custom_target(UnifiedRuntimeAdapters)
+
+function(add_sycl_ur_adapter NAME)
+ add_dependencies(UnifiedRuntimeAdapters ur_adapter_${NAME})
+endfunction()
+
+if("level_zero" IN_LIST LIBSYCL_ENABLE_BACKENDS)
+ add_sycl_ur_adapter(level_zero)
+endif()
+
+if("cuda" IN_LIST LIBSYCL_ENABLE_BACKENDS)
+ add_sycl_ur_adapter(cuda)
+endif()
+
+if("hip" IN_LIST LIBSYCL_ENABLE_BACKENDS)
+ add_sycl_ur_adapter(hip)
+endif()
+
+if("opencl" IN_LIST LIBSYCL_ENABLE_BACKENDS)
+ add_sycl_ur_adapter(opencl)
+endif()
diff --git a/libsycl/docs/DesignDocs/UnifiedRuntime.rst b/libsycl/docs/DesignDocs/UnifiedRuntime.rst
new file mode 100644
index 0000000000000..f4322c13c68b4
--- /dev/null
+++ b/libsycl/docs/DesignDocs/UnifiedRuntime.rst
@@ -0,0 +1,23 @@
+=====================
+Unified Runtime
+=====================
+
+.. contents::
+ :local:
+
+.. _unified runtime:
+
+The Unified Runtime (UR) project serves as an interface layer between the SYCL
+runtime and the device-specific runtime layers which control execution on
+devices. SYCL RT utilizes its C API, loader library, and the adapter libraries
+that implement the API for various backends.
+
+The SYCL runtime accesses the UR API via the Adapter object. Each Adapter
+object owns a ``ur_adapter_handle_t``, which represents a UR backend (e.g. OpenCL,
+Level Zero, etc).
+
+For detailed information about the UR project including
+the API specification see the `Unified Runtime Documentation
+<https://oneapi-src.github.io/unified-runtime/core/INTRO.html>`__. You
+can find the Unified Runtime repo `here
+<https://github.com/oneapi-src/unified-runtime>`__.
diff --git a/libsycl/src/CMakeLists.txt b/libsycl/src/CMakeLists.txt
index 206b85681cb84..b31da90bb8d24 100644
--- a/libsycl/src/CMakeLists.txt
+++ b/libsycl/src/CMakeLists.txt
@@ -2,10 +2,6 @@ list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/../../runtimes/cmake/
include(WarningFlags)
function(add_sycl_rt_library LIB_TARGET_NAME LIB_OBJ_NAME LIB_OUTPUT_NAME)
- if (NOT LLVM_ENABLE_PIC)
- message( FATAL_ERROR "Position-Independent Code generation is required for libsycl shared library" )
- endif()
-
cmake_parse_arguments(ARG "" "" "COMPILE_OPTIONS;SOURCES" ${ARGN})
add_library(${LIB_OBJ_NAME} OBJECT ${ARG_SOURCES})
@@ -22,6 +18,13 @@ function(add_sycl_rt_library LIB_TARGET_NAME LIB_OBJ_NAME LIB_OUTPUT_NAME)
${LIBSYCL_BUILD_INCLUDE_DIR}
)
+ # Object libraries are not linked, so these "libraries" are in fact include
+ # directories
+ target_link_libraries(${LIB_OBJ_NAME}
+ PRIVATE
+ UnifiedRuntime-Headers
+ )
+
add_library(${LIB_TARGET_NAME} SHARED
$<TARGET_OBJECTS:${LIB_OBJ_NAME}>)
@@ -49,7 +52,7 @@ function(add_sycl_rt_library LIB_TARGET_NAME LIB_OBJ_NAME LIB_OUTPUT_NAME)
target_compile_options(${LIB_OBJ_NAME} PUBLIC /EHsc)
else()
target_compile_options(${LIB_OBJ_NAME} PUBLIC
- -fvisibility=hidden -fvisibility-inlines-hidden)
+ -fvisibility=hidden -fvisibility-inlines-hidden -fPIC)
if (UNIX AND NOT APPLE)
set(linker_script "${CMAKE_CURRENT_SOURCE_DIR}/ld-version-script.txt")
@@ -65,6 +68,7 @@ function(add_sycl_rt_library LIB_TARGET_NAME LIB_OBJ_NAME LIB_OUTPUT_NAME)
PRIVATE
${CMAKE_DL_LIBS}
${CMAKE_THREAD_LIBS_INIT}
+ UnifiedRuntimeLoader
)
set_target_properties(${LIB_TARGET_NAME} PROPERTIES
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