fix: mark Eigen library as SYSTEM

[xmfcx]

Allows it to build with ros2 humble on arm64 systems.

Makes compiler treat the Eigen as a system library, as it should.

Without the fix, we encounter following issues:

autowarefoundation/autoware#2448

Follow up from: tier4#2 (review)

[xmfcx]

@wep21 could you review it?

[kenji-miyake]

Same error in grid_map_cv.

--- stderr: grid_map_cv
In file included from /usr/include/eigen3/Eigen/Core:214,
                 from /autoware/install/grid_map_core/include/grid_map_core/TypeDefs.hpp:13,
                 from /autoware/install/grid_map_core/include/grid_map_core/grid_map_core.hpp:12,
                 from /autoware/src/universe/vendor/grid_map/grid_map_cv/include/grid_map_cv/GridMapCvProcessing.hpp:12,
                 from /autoware/src/universe/vendor/grid_map/grid_map_cv/src/GridMapCvProcessing.cpp:9:
/usr/include/eigen3/Eigen/src/Core/arch/NEON/PacketMath.h: In function ‘Packet Eigen::internal::pload(const typename Eigen::internal::unpacket_traits<T>::type*) [with Packet = Eigen::internal::eigen_packet_wrapper<int, 2>; typename Eigen::internal::unpacket_traits<T>::type = signed char]’:
/usr/include/eigen3/Eigen/src/Core/arch/NEON/PacketMath.h:1671:9: error: ‘void* memcpy(void*, const void*, size_t)’ copying an object of non-trivial type ‘Eigen::internal::Packet4c’ {aka ‘struct Eigen::internal::eigen_packet_wrapper<int, 2>’} from an array of ‘const int8_t’ {aka ‘const signed char’} [-Werror=class-memaccess]
 1671 |   memcpy(&res, from, sizeof(Packet4c));
      |   ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

So we have to export the settings of system include. (But I'm not sure how to do that.)

[xmfcx]

I can apply it to the others too. I will do it in a few hours.

[kenji-miyake]

Thanks, but I guess the problem isn't so simple.
grid_map_cv doesn't directly depend on Eigen. It's propagated through grid_map_core.

[kenji-miyake]

ament_target_dependencies accepts the arg SYSTEM.
https://github.com/ament/ament_cmake/blob/6948e3c390715538a4b57263922a08a9fbb21a4f/ament_cmake_target_dependencies/cmake/ament_target_dependencies.cmake#L51

Editing here resolved the error.
https://github.com/tier4/grid_map/blob/6141088df232ee104cef8e1182f6a59a460642ce/grid_map_cv/CMakeLists.txt#L46

tier4@847f97f

[kenji-miyake]

Same error for grid_map_ros.

--- stderr: grid_map_ros
In file included from /usr/include/eigen3/Eigen/Core:214,
                 from /autoware/install/grid_map_core/include/grid_map_core/TypeDefs.hpp:13,
                 from /autoware/install/grid_map_core/include/grid_map_core/grid_map_core.hpp:12,
                 from /autoware/install/grid_map_cv/include/grid_map_cv/grid_map_cv.hpp:12,
                 from /autoware/src/universe/vendor/grid_map/grid_map_ros/src/GridMapRosConverter.cpp:21:
/usr/include/eigen3/Eigen/src/Core/arch/NEON/PacketMath.h: In function ‘Packet Eigen::internal::pload(const typename Eigen::internal::unpacket_traits<T>::type*) [with Packet = Eigen::internal::eigen_packet_wrapper<int, 2>; typename Eigen::internal::unpacket_traits<T>::type = signed char]’:
/usr/include/eigen3/Eigen/src/Core/arch/NEON/PacketMath.h:1671:9: error: ‘void* memcpy(void*, const void*, size_t)’ copying an object of non-trivial type ‘Eigen::internal::Packet4c’ {aka ‘struct Eigen::internal::eigen_packet_wrapper<int, 2>’} from an array of ‘const int8_t’ {aka ‘const signed char’} [-Werror=class-memaccess]
 1671 |   memcpy(&res, from, sizeof(Packet4c));

[kenji-miyake]

Also in grid_map_loader.

--- stderr: grid_map_loader
In file included from /usr/include/eigen3/Eigen/Core:214,
                 from /autoware/install/grid_map_core/include/grid_map_core/TypeDefs.hpp:13,
                 from /autoware/install/grid_map_core/include/grid_map_core/grid_map_core.hpp:12,
                 from /autoware/install/grid_map_ros/include/grid_map_ros/grid_map_ros.hpp:12,
                 from /autoware/src/universe/vendor/grid_map/grid_map_loader/include/grid_map_loader/GridMapLoader.hpp:17,
                 from /autoware/src/universe/vendor/grid_map/grid_map_loader/src/GridMapLoader.cpp:10:
/usr/include/eigen3/Eigen/src/Core/arch/NEON/PacketMath.h: In function ‘Packet Eigen::internal::pload(const typename Eigen::internal::unpacket_traits<T>::type*) [with Packet = Eigen::internal::eigen_packet_wrapper<int, 2>; typename Eigen::internal::unpacket_traits<T>::type = signed char]’:
/usr/include/eigen3/Eigen/src/Core/arch/NEON/PacketMath.h:1671:9: error: ‘void* memcpy(void*, const void*, size_t)’ copying an object of non-trivial type ‘Eigen::internal::Packet4c’ {aka ‘struct Eigen::internal::eigen_packet_wrapper<int, 2>’} from an array of ‘const int8_t’ {aka ‘const signed char’} [-Werror=class-memaccess]
 1671 |   memcpy(&res, from, sizeof(Packet4c));
      |   ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[kenji-miyake]

@xmfcx Could you cherry-pick tier4@91febb2?

[xmfcx]

I have tested this and it builds.
colcon build --symlink-install --cmake-args -DCMAKE_EXPORT_COMPILE_COMMANDS=1 --packages-up-to grid_map

I have tried to add SYSTEM keyword to only places where include_directories(${EIGEN3_INCLUDE_DIR} happened but that wasn't enough like @kenji-miyake said. Adding them to ament_target_dependencies solved the issue.

[xmfcx]

@maximilianwulf could you review/merge this please?

[maximilianwulf]

Yes, sorry support is on a super low burner.