Add libcu++ dependency.

cub/cmake/cub-config.cmake

@@ -8,6 +8,9 @@ if (TARGET CUB::CUB)
   return()
 endif()
 
+# Minimum supported libcudacxx version:
+set(cub_libcudacxx_version 1.8.0)
+
 function(_cub_declare_interface_alias alias_name ugly_name)
   # 1) Only IMPORTED and ALIAS targets can be placed in a namespace.
   # 2) When an IMPORTED library is linked to another target, its include
@@ -27,16 +30,64 @@ function(_cub_declare_interface_alias alias_name ugly_name)
 endfunction()
 
 #
-# Setup targets
+# Setup some internal cache variables
 #
 
-_cub_declare_interface_alias(CUB::CUB _CUB_CUB)
 # Pull in the include dir detected by cub-config-version.cmake
 set(_CUB_INCLUDE_DIR "${_CUB_VERSION_INCLUDE_DIR}"
   CACHE INTERNAL "Location of CUB headers."
+  FORCE
 )
 unset(_CUB_VERSION_INCLUDE_DIR CACHE) # Clear tmp variable from cache
+
+if (${CMAKE_FIND_PACKAGE_NAME}_FIND_QUIETLY)
+  set(_CUB_QUIET ON CACHE INTERNAL "Quiet mode enabled for CUB find_package calls." FORCE)
+  set(_CUB_QUIET_FLAG "QUIET" CACHE INTERNAL "" FORCE)
+else()
+  set(_CUB_QUIET OFF CACHE INTERNAL "Quiet mode enabled for CUB find_package calls." FORCE)
+  set(_CUB_QUIET_FLAG "" CACHE INTERNAL "" FORCE)
+endif()
+
+#
+# Setup dependencies
+#
+
+if (NOT TARGET CUB::libcudacxx)
+  if (TARGET Thrust::libcudacxx)
+    # Prefer the same libcudacxx as Thrust, if available:
+    _cub_declare_interface_alias(CUB::libcudacxx _CUB_libcudacxx)
+    target_link_libraries(_CUB_libcudacxx INTERFACE Thrust::libcudacxx)
+  else()
+    if (NOT TARGET libcudacxx::libcudacxx)
+      # First do a non-required search for any co-packaged versions.
+      # These are preferred.
+      find_package(libcudacxx ${cub_libcudacxx_version} CONFIG
+        ${_CUB_QUIET_FLAG}
+        NO_DEFAULT_PATH # Only check the explicit HINTS below:
+        HINTS
+          "${_CUB_INCLUDE_DIR}/../libcudacxx"           # Source layout
+          "${_CUB_CMAKE_DIR}/.."                        # Install layout
+      )
+
+      # A second required search allows externally packaged to be used and fails if
+      # no suitable package exists.
+      find_package(libcudacxx ${cub_libcudacxx_version} CONFIG
+        REQUIRED
+        ${_CUB_QUIET_FLAG}
+      )
+    endif()
+    _cub_declare_interface_alias(CUB::libcudacxx _CUB_libcudacxx)
+    target_link_libraries(_CUB_libcudacxx INTERFACE libcudacxx::libcudacxx)
+  endif()
+endif()
+
+#
+# Setup targets
+#
+
+_cub_declare_interface_alias(CUB::CUB _CUB_CUB)
 target_include_directories(_CUB_CUB INTERFACE "${_CUB_INCLUDE_DIR}")
+target_link_libraries(_CUB_CUB INTERFACE CUB::libcudacxx)
 
 if (CUB_IGNORE_DEPRECATED_API OR THRUST_IGNORE_DEPRECATED_API)
   target_compile_definitions(_CUB_CUB INTERFACE "CUB_IGNORE_DEPRECATED_API")
@@ -61,12 +112,12 @@ endif()
 # Standardize version info
 #
 
-set(CUB_VERSION ${${CMAKE_FIND_PACKAGE_NAME}_VERSION} CACHE INTERNAL "")
-set(CUB_VERSION_MAJOR ${${CMAKE_FIND_PACKAGE_NAME}_VERSION_MAJOR} CACHE INTERNAL "")
-set(CUB_VERSION_MINOR ${${CMAKE_FIND_PACKAGE_NAME}_VERSION_MINOR} CACHE INTERNAL "")
-set(CUB_VERSION_PATCH ${${CMAKE_FIND_PACKAGE_NAME}_VERSION_PATCH} CACHE INTERNAL "")
-set(CUB_VERSION_TWEAK ${${CMAKE_FIND_PACKAGE_NAME}_VERSION_TWEAK} CACHE INTERNAL "")
-set(CUB_VERSION_COUNT ${${CMAKE_FIND_PACKAGE_NAME}_VERSION_COUNT} CACHE INTERNAL "")
+set(CUB_VERSION ${${CMAKE_FIND_PACKAGE_NAME}_VERSION} CACHE INTERNAL "" FORCE)
+set(CUB_VERSION_MAJOR ${${CMAKE_FIND_PACKAGE_NAME}_VERSION_MAJOR} CACHE INTERNAL "" FORCE)
+set(CUB_VERSION_MINOR ${${CMAKE_FIND_PACKAGE_NAME}_VERSION_MINOR} CACHE INTERNAL "" FORCE)
+set(CUB_VERSION_PATCH ${${CMAKE_FIND_PACKAGE_NAME}_VERSION_PATCH} CACHE INTERNAL "" FORCE)
+set(CUB_VERSION_TWEAK ${${CMAKE_FIND_PACKAGE_NAME}_VERSION_TWEAK} CACHE INTERNAL "" FORCE)
+set(CUB_VERSION_COUNT ${${CMAKE_FIND_PACKAGE_NAME}_VERSION_COUNT} CACHE INTERNAL "" FORCE)
 
 include(FindPackageHandleStandardArgs)
 if (NOT CUB_CONFIG)