[SYCL] Detect changes in sycl headers

When subdirectory of the DEPENDS directories are modified the change is not
detected by CMake. The change set full list of files in subdirectory to
DEPENDS to detect the change. file(GLOBE_RECURSE) is used with
CONFIGURE_DEPENDS option to rerun configure if new entry is added to
directory structure.
Restore version.hpp in source directory as it is used to build SYCL
library.

Removing header file is the only case when change is not propagated to
build and install directory. This problem existed before the change and
TODO was left to fix it in future.

Author: vladimirlaz

sycl/.gitignore

@@ -0,0 +1 @@
+include/CL/sycl/version.hpp

sycl/CMakeLists.txt

@@ -98,27 +98,34 @@ set(sycl_inc_dir ${CMAKE_CURRENT_SOURCE_DIR}/include)
 set(sycl_src_dir ${CMAKE_CURRENT_SOURCE_DIR}/source)
 set(sycl_plugin_dir ${CMAKE_CURRENT_SOURCE_DIR}/plugins)
 string(TIMESTAMP __SYCL_COMPILER_VERSION "%Y%m%d")
+set(version_header "${sycl_inc_dir}/CL/sycl/version.hpp")
+configure_file("${version_header}.in" "${version_header}")
+
+# This is workaround to detect changes (add or modify) in subtree which
+# are not detected by copy_directory command.
+# TODO: detect and process remove header/directory case
+file(GLOB_RECURSE HEADERS_IN_SYCL_DIR CONFIGURE_DEPENDS "${sycl_inc_dir}/sycl/*")
+file(GLOB_RECURSE HEADERS_IN_CL_DIR CONFIGURE_DEPENDS "${sycl_inc_dir}/CL/*")
 
 # Copy SYCL headers from sources to build directory
 add_custom_target(sycl-headers
   DEPENDS ${SYCL_INCLUDE_BUILD_DIR}/sycl
+          ${SYCL_INCLUDE_BUILD_DIR}/sycl/sycl.hpp
           ${SYCL_INCLUDE_BUILD_DIR}/sycl/CL)
 
 add_custom_command(
   OUTPUT  ${SYCL_INCLUDE_BUILD_DIR}/sycl
+          ${SYCL_INCLUDE_BUILD_DIR}/sycl/sycl.hpp
           ${SYCL_INCLUDE_BUILD_DIR}/sycl/CL
-  DEPENDS ${sycl_inc_dir}/sycl
-          ${sycl_inc_dir}/CL
+  DEPENDS ${HEADERS_IN_SYCL_DIR}
+          ${HEADERS_IN_CL_DIR}
   COMMAND ${CMAKE_COMMAND} -E copy_directory ${sycl_inc_dir}/sycl ${SYCL_INCLUDE_BUILD_DIR}/sycl
   COMMAND ${CMAKE_COMMAND} -E copy_directory ${sycl_inc_dir}/CL ${SYCL_INCLUDE_BUILD_DIR}/sycl/CL
   COMMENT "Copying SYCL headers ...")
 
-configure_file("${sycl_inc_dir}/CL/sycl/version.hpp.in" "${SYCL_INCLUDE_BUILD_DIR}/CL/sycl/version.hpp")
-
-
-# Copy SYCL headers from sources to install directory
-install(DIRECTORY "${sycl_inc_dir}/sycl" DESTINATION ${SYCL_INCLUDE_DIR} COMPONENT sycl-headers)
-install(DIRECTORY "${sycl_inc_dir}/CL" DESTINATION ${SYCL_INCLUDE_DIR}/sycl COMPONENT sycl-headers)
+# Copy SYCL headers from build to install directory
+install(DIRECTORY "${SYCL_INCLUDE_BUILD_DIR}/sycl" DESTINATION ${SYCL_INCLUDE_DIR} COMPONENT sycl-headers)
+install(FILES "${version_header}" DESTINATION ${SYCL_INCLUDE_DIR}/sycl/CL/sycl COMPONENT sycl-headers)
 
 set(SYCL_RT_LIBS sycl)
 if (MSVC)

xpti/CMakeLists.txt

@@ -77,12 +77,13 @@ set(LIBRARY_OUTPUT_PATH ${CMAKE_BINARY_DIR})
 add_subdirectory(src)
 
 if (LLVM_BINARY_DIR)
+  file(GLOB_RECURSE XPTI_HEADERS_LIST CONFIGURE_DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/include/xpti/*")
   add_custom_target(xpti-headers
     DEPENDS ${LLVM_BINARY_DIR}/include/xpti)
 
   add_custom_command(
     OUTPUT  ${LLVM_BINARY_DIR}/include/xpti
-    DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/include/xpti
+    DEPENDS ${XPTI_HEADERS_LIST}
     COMMAND ${CMAKE_COMMAND} -E copy_directory
       ${CMAKE_CURRENT_SOURCE_DIR}/include/xpti
       ${LLVM_BINARY_DIR}/include/xpti