Switch to CCCL 2.2.0+ from Thrust/Cub 1.x

Closes #1021

cmake/common.cmake

@@ -28,7 +28,7 @@ endif()
 
 # Ensure that other dependencies are downloaded and available. 
 # As flamegpu is a static library, linking only only occurs at consumption not generation, so dependent targets must also know of PRIVATE shared library dependencies such as tinyxml2 and rapidjson, as well any intentionally public dependencies (for include dirs)
-include(${CMAKE_CURRENT_LIST_DIR}/dependencies/Thrust.cmake)
+include(${CMAKE_CURRENT_LIST_DIR}/dependencies/CCCL.cmake)
 include(${CMAKE_CURRENT_LIST_DIR}/dependencies/Jitify.cmake)
 include(${CMAKE_CURRENT_LIST_DIR}/dependencies/Tinyxml2.cmake)
 include(${CMAKE_CURRENT_LIST_DIR}/dependencies/rapidjson.cmake)

cmake/dependencies/CCCL.cmake

@@ -0,0 +1,71 @@
+###################################
+# CCCL (Thrust, CUB and libcucxx) #
+###################################
+
+set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_LIST_DIR}/modules/ ${CMAKE_MODULE_PATH})
+
+include(FetchContent)
+cmake_policy(SET CMP0079 NEW)
+
+# Set the minimum supported CCCL version, and the version to fetch
+# using find_package(version) means it's up to CCCL's cmake to determine if newer versions are compatible, but this will likely need changing for CUDA 13, when CCCL is planned to have a major version bump (and drop CUDA 11 support).
+set(MIN_REQUIRED_CCCL_VERSION 2.2.0)
+set(CCCL_DOWNLOAD_TAG v2.2.0)
+
+# Use the FindCUDATooklit package (CMake > 3.17) to get the CUDA version and CUDA include directories for cub/thrust location hints
+find_package(CUDAToolkit REQUIRED)
+
+# Quietly find CCCL, to check if the version included with CUDA (if CCCL) is sufficiently new.
+# Using CCCL avoids complex cub/thrust version workarounds previously required.
+# However we cannot find thrust due to a missing guard in CCCL's cmake config file, and cannot find cub without finding libcudacxx, so just find libcudacxx quietly.
+# If/when we change the minimum CCCL to 2.3.0 we should be able to remove the `components libcudacxx`. 
+find_package(CCCL ${MIN_REQUIRED_CCCL_VERSION} QUIET COMPONENTS libcudacxx CONFIG HINTS ${CUDAToolkit_INCLUDE_DIRS} ${CUDAToolkit_LIBRARY_DIR}/cmake)
+
+# If CCCL was found, find it again but loudly (with all components)
+if(CCCL_FOUND)
+    # Find the packages again but less quietly (and include all components)
+    find_package(CCCL ${MIN_REQUIRED_CCCL_VERSION} REQUIRED CONFIG COMPONENTS HINTS ${CUDAToolkit_INCLUDE_DIRS} ${CUDAToolkit_LIBRARY_DIR}/cmake)
+# If CCCL does need downloading, fetch it and find it (no need to add_subdirectory)
+else()
+    # Declare information about where and what we want from thrust.
+    FetchContent_Declare(
+        cccl
+        GIT_REPOSITORY https://github.com/NVIDIA/CCCL.git
+        GIT_TAG        ${CCCL_DOWNLOAD_TAG}
+        GIT_SHALLOW    1
+        GIT_PROGRESS   ON
+        # UPDATE_DISCONNECTED   ON
+    )
+    # Fetch and populate the content if required.
+    FetchContent_GetProperties(cccl)
+    if(NOT cccl_POPULATED)
+        message(STATUS "Fetching CCCL ${CCCL_DOWNLOAD_TAG}")
+        FetchContent_Populate(cccl)
+        # Use find_package for CCLL, only looking for the fetched version.
+        # This creates a non-system target due to nvcc magic to avoid the cuda toolkit version being used instead, so warnings are not suppressible without push/pop macros.
+        find_package(CCCL REQUIRED CONFIG
+            PATHS "${cccl_SOURCE_DIR}"
+            NO_CMAKE_PATH
+            NO_CMAKE_ENVIRONMENT_PATH
+            NO_SYSTEM_ENVIRONMENT_PATH
+            NO_CMAKE_PACKAGE_REGISTRY
+            NO_CMAKE_SYSTEM_PATH)
+    endif()
+    # Mark some CACHE vars as advanced for a cleaner CMake GUI
+    mark_as_advanced(FETCHCONTENT_QUIET)
+    mark_as_advanced(FETCHCONTENT_BASE_DIR)
+    mark_as_advanced(FETCHCONTENT_FULLY_DISCONNECTED)
+    mark_as_advanced(FETCHCONTENT_UPDATES_DISCONNECTED)
+    mark_as_advanced(FETCHCONTENT_SOURCE_DIR_CCCL)
+    mark_as_advanced(FETCHCONTENT_UPDATES_DISCONNECTED_CCCL)
+endif()
+
+# Unset temporary variables
+unset(MIN_REQUIRED_CCCL_VERSION)
+unset(CCCL_DOWNLOAD_TAG)
+
+# Mark some CACHE vars as advanced for a cleaner CMake GUI
+mark_as_advanced(CCCL_DIR)
+mark_as_advanced(CUB_DIR)
+mark_as_advanced(Thrust_DIR)
+mark_as_advanced(libcudacxx_DIR)

src/CMakeLists.txt

@@ -642,9 +642,8 @@ set_property(TARGET ${PROJECT_NAME}  PROPERTY CUDA_SEPARABLE_COMPILATION ON)
 
 # Link against dependency targets / directories.
 
-# Cub and thrust targets are not imported targets, so they do not use -isystem, so warnings must be suppressed as pragmas as requied. This is due to nvcc magic preventing isystem from being reliable with them. 
-target_link_libraries(${PROJECT_NAME} PUBLIC CUB::CUB)
-target_link_libraries(${PROJECT_NAME} PUBLIC Thrust::Thrust)
+# CCCL for Cub and thrust (and libcudacxx) targets are not imported targets, so they do not use -isystem, so warnings must be suppressed as pragmas if required. This is due to nvcc magic implicit include directory search ordering
+target_link_libraries(${PROJECT_NAME} PUBLIC CCCL::CCCL)
 
 # tinyxml2 static library
 target_link_libraries(${PROJECT_NAME} PRIVATE Tinyxml2::tinyxml2)