[llvm] [SYCL] Add libsycl, a SYCL RT library implementation project (PR #144372)

[Kseniya Tikhomirova via llvm-commits]

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+#===============================================================================
+# Setup Project
+#===============================================================================
+cmake_minimum_required(VERSION 3.20.0)
+
+set(LLVM_SUBPROJECT_TITLE "libsycl")
+
+set(LIBSYCL_SOURCE_DIR  ${CMAKE_CURRENT_SOURCE_DIR})
+set(LIBSYCL_BINARY_DIR  ${CMAKE_CURRENT_BINARY_DIR})
+
+set(CMAKE_CXX_STANDARD 17 CACHE STRING "C++ standard to conform to")
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
+set(CMAKE_CXX_EXTENSIONS OFF)
+
+#===============================================================================
+# Setup CMake Options
+#===============================================================================
+
+option(LIBSYCL_ENABLE_WERROR "Treat all warnings as errors in the libsycl project" OFF)
+
+#===============================================================================
+# Configure System
+#===============================================================================
+
+set_property(GLOBAL PROPERTY USE_FOLDERS ON)
+
+set(LIBSYCL_SHARED_OUTPUT_NAME "sycl" CACHE STRING "Output name for the shared libsycl runtime library.")
+
+if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
+  set(LIBSYCL_TARGET_SUBDIR ${LLVM_DEFAULT_TARGET_TRIPLE})
+  if(LIBSYCL_LIBDIR_SUBDIR)
+    string(APPEND LIBSYCL_TARGET_SUBDIR /${LIBSYCL_LIBDIR_SUBDIR})
+  endif()
+  cmake_path(NORMAL_PATH LIBSYCL_TARGET_SUBDIR)
+  set(LIBSYCL_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/${LIBSYCL_TARGET_SUBDIR})
+  set(LIBSYCL_INSTALL_LIBRARY_DIR lib${LLVM_LIBDIR_SUFFIX}/${LIBSYCL_TARGET_SUBDIR} CACHE STRING
+      "Path where built libsycl libraries should be installed.")
+  unset(LIBSYCL_TARGET_SUBDIR)
+else()
+  if(LLVM_LIBRARY_OUTPUT_INTDIR)
+    set(LIBSYCL_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
+  else()
+    set(LIBSYCL_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LIBSYCL_LIBDIR_SUFFIX})
+  endif()
+  set(LIBSYCL_INSTALL_LIBRARY_DIR lib${LIBSYCL_LIBDIR_SUFFIX} CACHE STRING
+      "Path where built libsycl libraries should be installed.")
+endif()
+
+set(LIBSYCL_INCLUDE_DIR include)
+set(LIBSYCL_BUILD_INCLUDE_DIR ${LLVM_BINARY_DIR}/${LIBSYCL_INCLUDE_DIR})
+set(LIBSYCL_SOURCE_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/include)
+
+set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBSYCL_LIBRARY_DIR})
+set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LIBSYCL_LIBRARY_DIR})
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LIBSYCL_LIBRARY_DIR})
+
+set(LIBSYCL_MAJOR_VERSION 0)
+set(LIBSYCL_MINOR_VERSION 1)
+set(LIBSYCL_PATCH_VERSION 0)
+set(LIBSYCL_VERSION_STRING "${LIBSYCL_MAJOR_VERSION}.${LIBSYCL_MINOR_VERSION}.${LIBSYCL_PATCH_VERSION}")
+set(LIBSYCL_ABI_NAMESPACE "V${LIBSYCL_MAJOR_VERSION}" CACHE STRING
+    "The inline ABI namespace used by libsycl. It defaults to Vn where `n` is the current ABI version.")
+
+#===============================================================================
+# Setup Compiler Flags
+#===============================================================================
+
+# Enable all warnings by default
+if(MSVC)
----------------
KseniyaTikhomirova wrote:

yes, we support MSVC. 

https://github.com/llvm/llvm-project/pull/144372