[Build][NFC] Split off libpfm detection to a separate module.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329783 91177308-0d34-0410-b5e6-96231b3b80d8

cmake/config-ix.cmake

@@ -90,17 +90,7 @@ if( NOT PURE_WINDOWS )
 endif()
 
 # Check for libpfm.
-if (LLVM_ENABLE_LIBPFM)
-  check_library_exists(pfm pfm_initialize "" HAVE_LIBPFM_INITIALIZE)
-  if(HAVE_LIBPFM_INITIALIZE)
-    check_include_file(perfmon/perf_event.h HAVE_PERFMON_PERF_EVENT_H)
-    check_include_file(perfmon/pfmlib.h HAVE_PERFMON_PFMLIB_H)
-    check_include_file(perfmon/pfmlib_perf_event.h HAVE_PERFMON_PFMLIB_PERF_EVENT_H)
-    if(HAVE_PERFMON_PERF_EVENT_H AND HAVE_PERFMON_PFMLIB_H AND HAVE_PERFMON_PFMLIB_PERF_EVENT_H)
-      set(HAVE_LIBPFM 1)
-    endif()
-  endif()
-endif()
+include(FindLibpfm)
 
 if(HAVE_LIBPTHREAD)
   # We want to find pthreads library and at the moment we do want to

cmake/modules/FindLibpfm.cmake

@@ -0,0 +1,23 @@
+# CMake module for finding libpfm4.
+#
+# If successful, the following variables will be defined:
+# HAVE_LIBPFM
+#
+# Libpfm can be disabled by setting LLVM_ENABLE_LIBPFM to 0.
+
+include(CheckIncludeFile)
+include(CheckLibraryExists)
+
+if (LLVM_ENABLE_LIBPFM)
+  check_library_exists(pfm pfm_initialize "" HAVE_LIBPFM_INITIALIZE)
+  if(HAVE_LIBPFM_INITIALIZE)
+    check_include_file(perfmon/perf_event.h HAVE_PERFMON_PERF_EVENT_H)
+    check_include_file(perfmon/pfmlib.h HAVE_PERFMON_PFMLIB_H)
+    check_include_file(perfmon/pfmlib_perf_event.h HAVE_PERFMON_PFMLIB_PERF_EVENT_H)
+    if(HAVE_PERFMON_PERF_EVENT_H AND HAVE_PERFMON_PFMLIB_H AND HAVE_PERFMON_PFMLIB_PERF_EVENT_H)
+      set(HAVE_LIBPFM 1)
+    endif()
+  endif()
+endif()
+
+