[llvm] [OFFLOAD] Add plugin with support for Intel oneAPI Level Zero (PR #158900)

[Alex Duran via llvm-commits]

================
@@ -0,0 +1,54 @@
+# Create the library and add the default arguments.
+add_target_library(omptarget.rtl.level_zero LEVEL_ZERO)
+
+set(LEVEL_ZERO_SRC_FILES
+  src/L0Context.cpp
+  src/L0Device.cpp
+  src/L0Kernel.cpp
+  src/L0Memory.cpp
+  src/L0Program.cpp
+  src/L0Plugin.cpp
+  src/L0Program.cpp
+  src/L0Options.cpp
+)
+
+target_sources(omptarget.rtl.level_zero PRIVATE
+  ${LEVEL_ZERO_SRC_FILES}
+)
+
+target_include_directories(omptarget.rtl.level_zero PRIVATE
+  ${CMAKE_CURRENT_SOURCE_DIR}/include
+)
+
+target_include_directories(omptarget.rtl.level_zero PRIVATE
+  ${LIBOMPTARGET_INCLUDE_DIR}
+  ${LIBOMPTARGET_DEP_LEVEL_ZERO_INCLUDE_DIR}
+  ${LIBOMPTARGET_LLVM_INCLUDE_DIRS}
+  ${LIBOMPTARGET_OMP_HEADER_DIR}
+)
+
+cmake_path(GET LIBOMPTARGET_DEP_LEVEL_ZERO_LIBRARY FILENAME LEVEL_ZERO_LIBRARY_NAME)
+if (EXISTS ${LIBOMPTARGET_DEP_LEVEL_ZERO_LIBRARY} AND NOT "level_zero" IN_LIST LIBOMPTARGET_DLOPEN_PLUGINS)
+  message(STATUS "Building Level Zero NG plugin linked against level_zero library")
+ if(UNIX)
+    target_link_libraries(omptarget.rtl.level_zero PRIVATE
+        ${LIBOMPTARGET_DEP_LEVEL_ZERO_LIBRARY})
+  elseif(WIN32)
+    # Full path to the Level Zero library is recognized as a linker option, so we
+    # separate directory and file name
+    cmake_path(GET LIBOMPTARGET_DEP_LEVEL_ZERO_LIBRARY PARENT_PATH LEVEL_ZERO_LIBRARY_PATH)
+    target_link_libraries(omptarget.rtl.level_zero PRIVATE ${LEVEL_ZERO_LIBRARY_NAME}
+        ${LIBOMP_LIB_FILE})
+    target_link_directories(omptarget.rtl.level_zero PRIVATE ${LEVEL_ZERO_LIBRARY_PATH})
+  else()
+    message(FATAL_ERROR "Missing platform support")
+  endif()
+else()
+  message(STATUS "Building Level Zero NG plugin for dlopened level_zero")
+  if(WIN32)
+    cmake_path(REPLACE_EXTENSION LEVEL_ZERO_LIBRARY_NAME dll)
+  endif()
----------------
adurang wrote:

The extension is different. Yes, we could do it in the source, but why would we want to do the required string manipulation at runtime when can be done statically here?

https://github.com/llvm/llvm-project/pull/158900