find_package use
This commit allows the sources of the project to be included in a parent
project CMakeLists.txt and support use of "find_package(Eigen3 CONFIG REQUIRED)"
Here is an example allowing to test the changes. It is not particularly
useful in itself. This change will allow to support one of the scenario
allowing to create custom 3D Slicer application bundling associated plugins.
/tmp/eigen-git-mirror # Eigen sources
/tmp/test/CMakeLists.txt:
cmake_minimum_required(VERSION 3.12)
project(test)
add_subdirectory("/tmp/eigen-git-mirror" "eigen-git-mirror")
find_package(Eigen3 CONFIG REQUIRED)
and configuring it using:
mkdir /tmp/test-build && cd $_
cmake \
-DCMAKE_FIND_PACKAGE_NO_PACKAGE_REGISTRY:BOOL=1 \
-DEigen3_DIR:PATH=/tmp/test-build/eigen-git-mirror \
/tmp/test
Co-authored-by: Pablo Hernandez <pablo.hernandez@kitware.com>
---
CMakeLists.txt | 1 +
cmake/Eigen3Config.cmake.in | 4 +++-
2 files changed, 4 insertions(+), 1 deletion(-)
There is currently a workaround for an issue in gcc that requires invoking gcc with the -fabi-version flag. This workaround is not needed for Clang and moreover is not supported.
And other related cmake cleanup, including:
- Use CMAKE_CURRENT_LIST_DIR to find UseEigen3.cmake
- Use INSTALL_DIR term consistently for variable names
- Drop unnecessary extra EIGEN_INCLUDE_INSTALL_DIR
- Fix some paths in generated eigen3.pc and Eigen3Config.cmake files
missing CMAKE_INSTALL_PREFIX
- Fix pkgconfig directory choice ignored if it doesn't exist at configure
time (bug #711)
- generate position-independent code (PIE), a requirement to run binaries on Android 5.0+ devices;
- correctly handle EIGEN_TEST_FMA + EIGEN_TEST_NEON to pass -mfpu=neon-vfpv4.
-mfpu=neon is not enough to activate NEON, since it's incompatible with the default float ABI,
and I have to pass -mfloat-abi=softfp (which is what everyone does in practice).
In fact, it would be a good idea to pass -mfloat-abi=softfp all the time, regardless of NEON.
Also removing the -mcpu=cortex-a8, as 1) it's not needed and 2) if we really wanted to pass
a specific -mcpu flag, that would presumably to tune performance for benchmarks, and it would
then not really make sense to tune for the very old cortex-a8 (it reflects ARM CPUs from 5 years ago).
