Symbol Visibility

[ax3l]

Other C++ template metaprogramming-heavy projects such as pybind11 make extensive use of symbol hiding via -fvisibility=hidden:

• https://pybind11.readthedocs.io/en/stable/faq.html#someclass-declared-with-greater-visibility-than-the-type-of-its-field-someclass-member-wattributes

This reduces binary size a lot - likely at the cost of less verbose callstack in crashes. It is worth investigating if the binary size change pays of for us and if it has further implications, maybe even in performance.

For an implementation, make it controllable via a CMake option (which is default ON in Release builds) and set the target property CXX_VISIBILITY_PRESET to hidden for selected PIConGPU targets. Note that there is also "inlines hidden" causing all inlined class member functions to have hidden visibility.