FindCUDA: Use the static CUDA runtime library if available (#15482)

Beginning in CUDA 5.5 a static version of the cuda runtime library
became available.  Since nvcc defaults to using this library over the
shared version, FindCUDA will also default to using this version.  There
are many advantages to using the static version (most importantly to
avoid conflicts with multiple versions when building a CUDA based
library).  Offer a CUDA_USE_STATIC_CUDA_RUNTIME option to control
this behavior.

Help/release/dev/FindCUDA-StaticRuntime.rst

@@ -0,0 +1,7 @@
+FindCUDA-StaticRuntime
+----------------------
+
+* The :module:`FindCUDA` module now defaults to using the static
+  CUDA runtime library if it is available.  A new
+  ``CUDA_USE_STATIC_CUDA_RUNTIME`` option is offered to control
+  this behavior.

Modules/FindCUDA.cmake

@@ -106,6 +106,11 @@
 #      CUDA_COMPUTE_SEPARABLE_COMPILATION_OBJECT_FILE_NAME and
 #      CUDA_LINK_SEPARABLE_COMPILATION_OBJECTS should be called.
 #
+#   CUDA_USE_STATIC_CUDA_RUNTIME (Default ON)
+#   -- When enabled the static version of the CUDA runtime library will be used
+#      in CUDA_LIBRARIES.  If the version of CUDA configured doesn't support
+#      this option, then it will be silently disabled.
+#
 #   CUDA_VERBOSE_BUILD (Default OFF)
 #   -- Set to ON to see all the commands used when building the CUDA file.  When
 #      using a Makefile generator the value defaults to VERBOSE (run make
@@ -272,6 +277,8 @@
 #   CUDA_CUBLAS_LIBRARIES -- Device or emulation library for the Cuda BLAS
 #                            implementation (alterative to:
 #                            CUDA_ADD_CUBLAS_TO_TARGET macro).
+#   CUDA_cudart_static_LIBRARY -- Statically linkable cuda runtime library.
+#                                 Only available for CUDA version 5.5+
 #   CUDA_cupti_LIBRARY    -- CUDA Profiling Tools Interface library.
 #                            Only available for CUDA version 4.0+.
 #   CUDA_curand_LIBRARY   -- CUDA Random Number Generation library.
@@ -518,11 +525,12 @@ macro(cuda_unset_include_and_libraries)
     # This only existed in the 3.0 version of the CUDA toolkit
     unset(CUDA_CUDARTEMU_LIBRARY CACHE)
   endif()
-  unset(CUDA_cupti_LIBRARY CACHE)
+  unset(CUDA_cudart_static_LIBRARY CACHE)
   unset(CUDA_cublas_LIBRARY CACHE)
   unset(CUDA_cublasemu_LIBRARY CACHE)
   unset(CUDA_cufft_LIBRARY CACHE)
   unset(CUDA_cufftemu_LIBRARY CACHE)
+  unset(CUDA_cupti_LIBRARY CACHE)
   unset(CUDA_curand_LIBRARY CACHE)
   unset(CUDA_cusolver_LIBRARY CACHE)
   unset(CUDA_cusparse_LIBRARY CACHE)
@@ -532,6 +540,8 @@ macro(cuda_unset_include_and_libraries)
   unset(CUDA_npps_LIBRARY CACHE)
   unset(CUDA_nvcuvenc_LIBRARY CACHE)
   unset(CUDA_nvcuvid_LIBRARY CACHE)
+
+  unset(CUDA_USE_STATIC_CUDA_RUNTIME CACHE)
 endmacro()
 
 # Check to see if the CUDA_TOOLKIT_ROOT_DIR and CUDA_SDK_ROOT_DIR have changed,
@@ -539,8 +549,8 @@ endmacro()
 if(NOT "${CUDA_TOOLKIT_ROOT_DIR}" STREQUAL "${CUDA_TOOLKIT_ROOT_DIR_INTERNAL}")
   unset(CUDA_TOOLKIT_TARGET_DIR CACHE)
   unset(CUDA_NVCC_EXECUTABLE CACHE)
-  unset(CUDA_VERSION CACHE)
   cuda_unset_include_and_libraries()
+  unset(CUDA_VERSION CACHE)
 endif()
 
 if(NOT "${CUDA_TOOLKIT_TARGET_DIR}" STREQUAL "${CUDA_TOOLKIT_TARGET_DIR_INTERNAL}")
@@ -696,6 +706,53 @@ if(CUDA_VERSION VERSION_EQUAL "3.0")
     CUDA_CUDARTEMU_LIBRARY
     )
 endif()
+if(NOT CUDA_VERSION VERSION_LESS "5.5")
+  cuda_find_library_local_first(CUDA_cudart_static_LIBRARY cudart_static "static CUDA runtime library")
+  mark_as_advanced(CUDA_cudart_static_LIBRARY)
+endif()
+if(CUDA_cudart_static_LIBRARY)
+  # Set whether to use the static cuda runtime.
+  option(CUDA_USE_STATIC_CUDA_RUNTIME "Use the static version of the CUDA runtime library if available" ON)
+else()
+  option(CUDA_USE_STATIC_CUDA_RUNTIME "Use the static version of the CUDA runtime library if available" OFF)
+endif()
+
+if(CUDA_USE_STATIC_CUDA_RUNTIME)
+  if(UNIX)
+    # Check for the dependent libraries.  Here we look for pthreads.
+    if (DEFINED CMAKE_THREAD_PREFER_PTHREAD)
+      set(_cuda_cmake_thread_prefer_pthread ${CMAKE_THREAD_PREFER_PTHREAD})
+    endif()
+    set(CMAKE_THREAD_PREFER_PTHREAD 1)
+
+    # Many of the FindXYZ CMake comes with makes use of try_compile with int main(){return 0;}
+    # as the source file.  Unfortunately this causes a warning with -Wstrict-prototypes and
+    # -Werror causes the try_compile to fail.  We will just temporarily disable other flags
+    # when doing the find_package command here.
+    set(_cuda_cmake_c_flags ${CMAKE_C_FLAGS})
+    set(CMAKE_C_FLAGS "-fPIC")
+    find_package(Threads REQUIRED)
+    set(CMAKE_C_FLAGS ${_cuda_cmake_c_flags})
+
+    if (DEFINED _cuda_cmake_thread_prefer_pthread)
+      set(CMAKE_THREAD_PREFER_PTHREAD ${_cuda_cmake_thread_prefer_pthread})
+      unset(_cuda_cmake_thread_prefer_pthread)
+    else()
+      unset(CMAKE_THREAD_PREFER_PTHREAD)
+    endif()
+    if (NOT APPLE)
+      # Here is librt that has things such as, clock_gettime, shm_open, and shm_unlink.
+      find_library(CUDA_rt_LIBRARY rt)
+      find_library(CUDA_dl_LIBRARY dl)
+      if (NOT CUDA_rt_LIBRARY)
+        message(WARNING "Expecting to find librt for libcudart_static, but didn't find it.")
+      endif()
+      if (NOT CUDA_dl_LIBRARY)
+        message(WARNING "Expecting to find libdl for libcudart_static, but didn't find it.")
+      endif()
+    endif()
+  endif()
+endif()
 
 # CUPTI library showed up in cuda toolkit 4.0
 if(NOT CUDA_VERSION VERSION_LESS "4.0")
@@ -703,12 +760,32 @@ if(NOT CUDA_VERSION VERSION_LESS "4.0")
   mark_as_advanced(CUDA_cupti_LIBRARY)
 endif()
 
+# Set the CUDA_LIBRARIES variable.  This is the set of stuff to link against if you are
+# using the CUDA runtime.  For the dynamic version of the runtime, most of the
+# dependencies are brough in, but for the static version there are additional libraries
+# and linker commands needed.
+# Initialize to empty
+set(CUDA_LIBRARIES)
+
 # If we are using emulation mode and we found the cudartemu library then use
 # that one instead of cudart.
 if(CUDA_BUILD_EMULATION AND CUDA_CUDARTEMU_LIBRARY)
-  set(CUDA_LIBRARIES ${CUDA_CUDARTEMU_LIBRARY})
+  list(APPEND CUDA_LIBRARIES ${CUDA_CUDARTEMU_LIBRARY})
+elseif(CUDA_USE_STATIC_CUDA_RUNTIME AND CUDA_cudart_static_LIBRARY)
+  list(APPEND CUDA_LIBRARIES ${CUDA_cudart_static_LIBRARY} ${CMAKE_THREAD_LIBS_INIT})
+  if (CUDA_rt_LIBRARY)
+    list(APPEND CUDA_LIBRARIES ${CUDA_rt_LIBRARY})
+  endif()
+  if (CUDA_dl_LIBRARY)
+    list(APPEND CUDA_LIBRARIES ${CUDA_dl_LIBRARY})
+  endif()
+  if(APPLE)
+    # We need to add the default path to the driver (libcuda.dylib) as an rpath, so that
+    # the static cuda runtime can find it at runtime.
+    list(APPEND CUDA_LIBRARIES -Wl,-rpath,/usr/local/cuda/lib)
+  endif()
 else()
-  set(CUDA_LIBRARIES ${CUDA_CUDART_LIBRARY})
+  list(APPEND CUDA_LIBRARIES ${CUDA_CUDART_LIBRARY})
 endif()
 
 # 1.1 toolkit on linux doesn't appear to have a separate library on