[OpenMP][OMPD] libompd must not link libomp (#83119)

Fixes a regression introduced in 91ccd82.
The code for libompd includes kmp.h for enum kmp_sched. The dependency
to hwloc is not necessary. Avoid the dependency by skipping the
definitions in kmp.h using types from hwloc.h.

Fixes #80750

Author: jprotze

openmp/libompd/src/CMakeLists.txt

@@ -13,7 +13,8 @@ cmake_minimum_required(VERSION 3.20.0)
 
 add_library (ompd SHARED TargetValue.cpp omp-debug.cpp omp-state.cpp omp-icv.cpp)
 
-target_link_libraries(ompd omp) # ensure generated import library is created first
+# libompd must not link against libomp, there is no code dependency.
+add_dependencies(ompd omp) # ensure generated import library is created first
 
 set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
 

openmp/libompd/src/omp-icv.cpp

@@ -18,7 +18,9 @@
 #include "omp.h"
 #include "ompd-private.h"
 #include "TargetValue.h"
+#define OMPD_SKIP_HWLOC 1
 #include "kmp.h"
+#undef OMPD_SKIP_HWLOC
 #include <cstring>
 
 /* The ICVs ompd-final-var and ompd-implicit-var below are for backward

openmp/runtime/src/kmp.h

@@ -103,7 +103,8 @@ class kmp_stats_list;
 #define KMP_USE_HIER_SCHED KMP_AFFINITY_SUPPORTED
 #endif
 
-#if KMP_USE_HWLOC && KMP_AFFINITY_SUPPORTED
+// OMPD_SKIP_HWLOC used in libompd/omp-icv.cpp to avoid OMPD depending on hwloc
+#if KMP_USE_HWLOC && KMP_AFFINITY_SUPPORTED && !defined(OMPD_SKIP_HWLOC)
 #include "hwloc.h"
 #ifndef HWLOC_OBJ_NUMANODE
 #define HWLOC_OBJ_NUMANODE HWLOC_OBJ_NODE
@@ -689,7 +690,7 @@ typedef BOOL (*kmp_SetThreadGroupAffinity_t)(HANDLE, const GROUP_AFFINITY *,
 extern kmp_SetThreadGroupAffinity_t __kmp_SetThreadGroupAffinity;
 #endif /* KMP_OS_WINDOWS */
 
-#if KMP_USE_HWLOC
+#if KMP_USE_HWLOC && !defined(OMPD_SKIP_HWLOC)
 extern hwloc_topology_t __kmp_hwloc_topology;
 extern int __kmp_hwloc_error;
 #endif