Why linker strips about 90% of used files / classes?

Hello,

I'm currently working on the project which is using proto buffers, which register descriptors globally this way:
```
PROTOBUF_ATTRIBUTE_INIT_PRIORITY2 static ::std::false_type
_static_init2_ PROTOBUF_UNUSED =
(::_pbi::AddDescriptors(&descriptor_table_mediapipe_2fcalculators_2ftensor_2ftensors_5fto_5fsegmentation_5fcalculator_2eproto),
::_pbi::ExtensionSet::RegisterMessageExtension(
&::mediapipe::CalculatorOptions::default_instance(), 374311106, 11,
false, false, &::mediapipe::TensorsToSegmentationCalculatorOptions::default_instance(),
nullptr, ::_pbi::LazyAnnotation::kUndefined),
::std::false_type{});
```
Here ::_pbi::AddDescriptors - just registeres the class in the global factory.
There are over 100 such .proto files / classes.

But during parsing .pbtxt files parser throws lot of errors regarding missing extensions.
It turns out linker just strips majority of my classes with self registration.
Currently i log all the registered descriptors and I was surprized that over 90% of my classes just stripped away.

Why linker strips the code which is potentially used in the final executable?

I checked generated ninja file and those .o files are linked to the static library libmediaPipe.a which is linked to final executable. So those classes should not be stripped.