[OpenMP] Add HWLOC compatibility check

[tianshilei1992]

Summary

Starting from LLVM 14 we are using HWLOC APIs from newer version, per
https://github.com/llvm/llvm-project/issues/54951, but our CMake check doesn't
include that part. Unfortunately HWLOC doesn't provide a proper CMake module for
find_package. We have to check if specific struct member exists before we use
that.

Fix #54951.

[jlpeyton]

openmp/runtime/cmake/config-ix.cmake

346–356

Move this below the check_struct_has_member call so the same hwloc.h header is used as the one in the check_include_file() call.

365

I think the name has to be different than LIBOMP_HAVE_LIBHWLOC or CMake will skip the check thinking it has already done it. Something like LIBOMP_HAVE_ATLEAST_LIBHWLOC2. Then just add the LIBOMP_HAVE_ATLEAST_LIBHWLOC2 to line 357 which checks all the necessary HWLOC requirements to determine if HWLOC is really available.

[tianshilei1992]

fix comment and refine the logic

[tianshilei1992]

openmp/runtime/cmake/config-ix.cmake

346–356

I think the logic here is, we first check if the header can be included, and then see if it is a valid one. Of course we could do it in another way. Either should work.

[jlpeyton]

Sorry! I just realized there's another patch that solves this problem by inserting the proper HWLOC version checks in the code mentioned here: https://reviews.llvm.org/D112270. I'd rather go with that approach since it allows older HWLOC versions.

[tianshilei1992]

In D142036#4066215, @jlpeyton wrote:

Sorry! I just realized there's another patch that solves this problem by inserting the proper HWLOC version checks in the code mentioned here: https://reviews.llvm.org/D112270. I'd rather go with that approach since it allows older HWLOC versions.

Sure. Can you please land it? Also, please add Fix #54951. at the end of the commit message such that the issue can be closed automatically. It'd be best if you can do it before the release branching. Thanks!

However, I didn't see where the version check is inserted. The comment mentioned 2.4. So that patch has to be rebased and the refined.

If that patch cannot make it before the release, I think it makes more sense to land this in case breaking more users.

[jlpeyton]

Ok I've made https://reviews.llvm.org/D142152 which combines @ggouaillardet 's patch with the other needed guard around line 1611 as you noted.

openmp/runtime/cmake/config-ix.cmake

else()
     set(LIBOMP_HAVE_OMPT_SUPPORT FALSE)
   endif()
 endif()
 
 set(LIBOMP_HAVE_OMPT_SUPPORT ${LIBOMP_HAVE_OMPT_SUPPORT} PARENT_SCOPE)
 
 # Check if HWLOC support is available
 if(${LIBOMP_USE_HWLOC})
+  # Check the header
   find_path(LIBOMP_HWLOC_INCLUDE_DIR NAMES hwloc.h HINTS ${LIBOMP_HWLOC_INSTALL_DIR} PATH_SUFFIXES include)
   set(CMAKE_REQUIRED_INCLUDES ${LIBOMP_HWLOC_INCLUDE_DIR})
   check_include_file(hwloc.h LIBOMP_HAVE_HWLOC_H)
   set(CMAKE_REQUIRED_INCLUDES)
+  if(LIBOMP_HAVE_HWLOC_H)
+    include(CheckStructHasMember)
+    # Check if struct hwloc_group_attr_s has kind as it is a new feature in HWLOC 2 and we need that.
+    check_struct_has_member("struct hwloc_group_attr_s" "kind" hwloc.h LIBOMP_HAVE_REQUIRED_HWLOC_H)
+    if(NOT LIBOMP_HAVE_REQUIRED_HWLOC_H)
+      set(LIBOMP_HAVE_HWLOC_H FALSE)
+    endif()
+  endif()
+
+  # Check the library
   find_library(LIBOMP_HWLOC_LIBRARY
     NAMES hwloc libhwloc
     HINTS ${LIBOMP_HWLOC_INSTALL_DIR}/lib)
   if(LIBOMP_HWLOC_LIBRARY)
     check_library_exists(${LIBOMP_HWLOC_LIBRARY} hwloc_topology_init
       ${LIBOMP_HWLOC_INSTALL_DIR}/lib LIBOMP_HAVE_LIBHWLOC)
+    if (NOT LIBOMP_HAVE_LIBHWLOC)
+      set(LIBOMP_HWLOC_LIBRARY FALSE)
+    else()
       get_filename_component(LIBOMP_HWLOC_LIBRARY_DIR ${LIBOMP_HWLOC_LIBRARY} PATH)
     endif()
-  if(LIBOMP_HAVE_HWLOC_H AND LIBOMP_HAVE_LIBHWLOC AND LIBOMP_HWLOC_LIBRARY)
+  endif()
+
+  if(LIBOMP_HAVE_HWLOC_H AND LIBOMP_HWLOC_LIBRARY)
     set(LIBOMP_HAVE_HWLOC TRUE)
   else()
     set(LIBOMP_HAVE_HWLOC FALSE)
-    libomp_say("Could not find hwloc")
+    libomp_say("Could not find required hwloc (version 2+)")
   endif()
 endif()
 
 # Check if ThreadSanitizer support is available
 if("${CMAKE_SYSTEM_NAME}" MATCHES "Linux" AND ${INTEL64})
   set(LIBOMP_HAVE_TSAN_SUPPORT TRUE)
 else()
   set(LIBOMP_HAVE_TSAN_SUPPORT FALSE)
 endif()