Cleaning up OpenMP handling in CMakeLists.
- Ensure that we disable the OPENMP option in the CMake GUI if we
are not using OpenMP.
- Add explanation of why we are not using OpenMP if compiler is Clang.
Change-Id: Ifae484e14a5e19bb59151a22b5c0c94ea5ea46bd
diff --git a/CMakeLists.txt b/CMakeLists.txt
index ad7e220..75967f2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -368,33 +368,46 @@
MESSAGE("-- Disabling custom blas")
ENDIF (NOT CUSTOM_BLAS)
-IF (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
- SET(OPENMP_FOUND FALSE)
-ELSE (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
- IF (OPENMP)
- FIND_PACKAGE(OpenMP REQUIRED)
- ENDIF (OPENMP)
-ENDIF (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
-
-IF (OPENMP_FOUND)
- MESSAGE("-- Found OpenMP.")
- ADD_DEFINITIONS(-DCERES_USE_OPENMP)
- SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
- IF (UNIX)
- # At least on Linux, we need pthreads to be enabled for mutex to
- # compile. This may not work on Windows or Android.
- FIND_PACKAGE(Threads REQUIRED)
- SET(STATIC_LIBRARY_FLAGS
- "${STATIC_LIBRARY_FLAGS} ${CMAKE_THREAD_LIBS_INIT}")
- SET(CMAKE_SHARED_LINKER_FLAGS
- "${CMAKE_SHARED_LINKER_FLAGS} ${CMAKE_THREAD_LIBS_INIT}")
- ADD_DEFINITIONS(-DCERES_HAVE_PTHREAD)
- ADD_DEFINITIONS(-DCERES_HAVE_RWLOCK)
- ENDIF (UNIX)
-ELSE (OPENMP_FOUND)
- MESSAGE("-- Can't find OpenMP. Disabling multithreading.")
+IF (OPENMP)
+ # Clang does not (yet) support OpenMP.
+ IF (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+ # Retain the help string associated with the OPENMP option
+ # when updating it to disable use of OPENMP.
+ GET_PROPERTY(HELP_STRING CACHE OPENMP PROPERTY HELPSTRING)
+ SET(OPENMP OFF CACHE BOOL "${HELP_STRING}" FORCE)
+ MESSAGE("-- Compiler is Clang, disabling OpenMP.")
+ ADD_DEFINITIONS(-DCERES_NO_THREADS)
+ ELSE (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+ # Find quietly s/t as we can continue without OpenMP if it is not found.
+ FIND_PACKAGE(OpenMP QUIET)
+ IF (OPENMP_FOUND)
+ MESSAGE("-- Building with OpenMP.")
+ ADD_DEFINITIONS(-DCERES_USE_OPENMP)
+ SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
+ IF (UNIX)
+ # At least on Linux, we need pthreads to be enabled for mutex to
+ # compile. This may not work on Windows or Android.
+ FIND_PACKAGE(Threads REQUIRED)
+ SET(STATIC_LIBRARY_FLAGS
+ "${STATIC_LIBRARY_FLAGS} ${CMAKE_THREAD_LIBS_INIT}")
+ SET(CMAKE_SHARED_LINKER_FLAGS
+ "${CMAKE_SHARED_LINKER_FLAGS} ${CMAKE_THREAD_LIBS_INIT}")
+ ADD_DEFINITIONS(-DCERES_HAVE_PTHREAD)
+ ADD_DEFINITIONS(-DCERES_HAVE_RWLOCK)
+ ENDIF (UNIX)
+ ELSE (OPENMP_FOUND)
+ MESSAGE("-- Failed to find OpenMP, disabling.")
+ # Retain the help string associated with the OPENMP option
+ # when updating it to disable use of OPENMP.
+ GET_PROPERTY(HELP_STRING CACHE OPENMP PROPERTY HELPSTRING)
+ SET(OPENMP OFF CACHE BOOL "${HELP_STRING}" FORCE)
+ ADD_DEFINITIONS(-DCERES_NO_THREADS)
+ ENDIF (OPENMP_FOUND)
+ ENDIF (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+ELSE (OPENMP)
+ MESSAGE("-- Building without OpenMP (disabling multithreading).")
ADD_DEFINITIONS(-DCERES_NO_THREADS)
-ENDIF (OPENMP_FOUND)
+ENDIF (OPENMP)
IF (DISABLE_TR1)
MESSAGE("-- Replacing unordered_map/set with map/set (warning: slower!)")
