The bulk of this feature already works in the master branch and will be part of %DUNE 2.10.0!
This is a "meta"-MR to gather all sub-tasks needed to achieve this and to explain its benefits.
Summary
The idea is to be able to enable CMake super builds following up on !848 (closed). That is, one top-level CMakeLists.txt that contains all other DUNE projects:
cmake_minimum_required(VERSION 3.24 FATAL_ERROR)project(dune-core CXX)# let 'find_package' know where configured projects can be foundlist(APPEND CMAKE_PREFIX_PATH ${PROJECT_BINARY_DIR})# allow dune to see imported targets across modulesset(CMAKE_FIND_PACKAGE_TARGETS_GLOBAL ON)# include DUNE sub-directories in configuration orderadd_subdirectory(dune-common)add_subdirectory(dune-istl)add_subdirectory(dune-geometry)add_subdirectory(dune-grid)add_subdirectory(dune-localfunctions)
with !1419 this file may even be generated automatically.
Faster Builds!
As an example, I configure and build all the modules for dune-functions, that is:
dune-common
dune-istl
dune-geometry
dune-uggrid
dune-grid
dune-localfunctions
dune-typetree
dune-functions
We get the faster times on both build and configuration (Tested on a Apple M3 Max 10+4 cores):
Time
dunecontrol (build+conf per module)
SuperBuild
Configuration
8.8+3.8+4.0+3.1+4.1+3.9+2.9+6.8 = 37.4s
21.4s
Build
4+1+1+5+4+7 = 22.0s
13.5s
Total
59.4s
34.9s
Configuration is faster because it's 1 big configuration instead of 8 small configuration stages.
Note that this approach on global imported targets avoids one of the most consuming part of our build: find packages over and over again!
Build is faster because all targets from different modules are together and can be built in parallel.
Simpler to use
Since building cmake projects is ubiquitous, it is much easier to teach how to use dune:
# obtain modules (with super build)git clone --recursive <my-super-build-module># prepare a build directorymkdir build &&cd build# configure the projectsCMAKE_BUILD_TYPE="Release" cmake -G Ninja ..# build the projectcmake --build.
No need to teach about dune-isms like dunecontrol or the dune options file! For the most part, it just works like any other C++ project.
IDE Integration
Since one multi module project set up is so simple, its set up on Integrated Development Environments is also easy. Compare automatic setup in VSCode when working with super builds vs a 3 stages of manual setup when working the traditional way.
Implementation
The following are the required steps to achieve this:
