Cycles: Add support for rendering on Intel GPUs using oneAPI

This patch adds a new Cycles device with similar functionality to the
existing GPU devices.  Kernel compilation and runtime interaction happen
via oneAPI DPC++ compiler and SYCL API.

This implementation is primarly focusing on Intel® Arc™ GPUs and other
future Intel GPUs.  The first supported drivers are 101.1660 on Windows
and 22.10.22597 on Linux.

The necessary tools for compilation are:
- A SYCL compiler such as oneAPI DPC++ compiler or
  https://github.com/intel/llvm
- Intel® oneAPI Level Zero which is used for low level device queries:
  https://github.com/oneapi-src/level-zero
- To optionally generate prebuilt graphics binaries: Intel® Graphics
  Compiler All are included in Linux precompiled libraries on svn:
  https://svn.blender.org/svnroot/bf-blender/trunk/lib The same goes for
  Windows precompiled binaries but for the graphics compiler, available
  as "Intel® Graphics Offline Compiler for OpenCL™ Code" from
  https://www.intel.com/content/www/us/en/developer/articles/tool/oneapi-standalone-components.html,
  for which path can be set as OCLOC_INSTALL_DIR.

Being based on the open SYCL standard, this implementation could also be
extended to run on other compatible non-Intel hardware in the future.

Reviewed By: sergey, brecht

Differential Revision: https://developer.blender.org/D15254

Co-authored-by: Nikita Sirgienko <nikita.sirgienko@intel.com>
Co-authored-by: Stefan Werner <stefan.werner@intel.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/build_files/build_environment/patches/dpcpp.diff b/build_files/build_environment/patches/dpcpp.diff
new file mode 100644
index 00000000000..9dbe032de0c
--- /dev/null
+++ b/build_files/build_environment/patches/dpcpp.diff
@@ -0,0 +1,54 @@
+diff -Naur external_dpcpp.orig/sycl/source/CMakeLists.txt external_dpcpp/sycl/source/CMakeLists.txt
+--- external_dpcpp.orig/sycl/source/CMakeLists.txt      2022-05-20 04:19:45.067771362 +0000
++++ external_dpcpp/sycl/source/CMakeLists.txt   2022-05-20 04:21:49.708025048 +0000
+@@ -66,10 +66,10 @@
+     target_compile_options(${LIB_OBJ_NAME} PUBLIC
+                            -fvisibility=hidden -fvisibility-inlines-hidden)
+     set(linker_script "${CMAKE_CURRENT_SOURCE_DIR}/ld-version-script.txt")
+-    set(abi_linker_script "${CMAKE_CURRENT_SOURCE_DIR}/abi_replacements_linux.txt")
+-    target_link_libraries(
+-      ${LIB_NAME} PRIVATE "-Wl,${abi_linker_script}")
+-    set_target_properties(${LIB_NAME} PROPERTIES LINK_DEPENDS ${abi_linker_script})
++#    set(abi_linker_script "${CMAKE_CURRENT_SOURCE_DIR}/abi_replacements_linux.txt")
++#    target_link_libraries(
++#      ${LIB_NAME} PRIVATE "-Wl,${abi_linker_script}")
++#    set_target_properties(${LIB_NAME} PROPERTIES LINK_DEPENDS ${abi_linker_script})
+     target_link_libraries(
+         ${LIB_NAME} PRIVATE "-Wl,--version-script=${linker_script}")
+     set_target_properties(${LIB_NAME} PROPERTIES LINK_DEPENDS ${linker_script})
+diff -Naur llvm-sycl-nightly-20220501.orig\opencl/CMakeLists.txt llvm-sycl-nightly-20220501\opencl/CMakeLists.txt
+--- llvm-sycl-nightly-20220501.orig/opencl/CMakeLists.txt       2022-04-29 13:47:11 -0600
++++ llvm-sycl-nightly-20220501/opencl/CMakeLists.txt    2022-05-21 15:25:06 -0600
+@@ -11,6 +11,11 @@
+   )
+ endif()
+
++# Blender code below is determined to use FetchContent_Declare
++# temporarily allow it (but feed it our downloaded tarball
++# in the OpenCL_HEADERS variable
++set(FETCHCONTENT_FULLY_DISCONNECTED OFF)
++
+ # Repo URLs
+
+ set(OCL_HEADERS_REPO
+@@ -77,5 +82,6 @@
+
+ FetchContent_MakeAvailable(ocl-icd)
+ add_library(OpenCL-ICD ALIAS OpenCL)
++set(FETCHCONTENT_FULLY_DISCONNECTED ON)
+
+ add_subdirectory(opencl-aot)
+diff -Naur llvm-sycl-nightly-20220208.orig/libdevice/cmake/modules/SYCLLibdevice.cmake llvm-sycl-nightly-20220208/libdevice/cmake/modules/SYCLLibdevice.cmake
+--- llvm-sycl-nightly-20220208.orig/libdevice/cmake/modules/SYCLLibdevice.cmake	2022-02-08 09:17:24 -0700
++++ llvm-sycl-nightly-20220208/libdevice/cmake/modules/SYCLLibdevice.cmake	2022-05-24 11:35:51 -0600
+@@ -36,7 +36,9 @@
+ add_custom_target(libsycldevice-obj)
+ add_custom_target(libsycldevice-spv)
+ 
+-add_custom_target(libsycldevice DEPENDS
++# Blender: add ALL here otherwise this target will not build
++# and cause an error due to missing files during the install phase.
++add_custom_target(libsycldevice ALL DEPENDS
+   libsycldevice-obj
+   libsycldevice-spv)
+