Indeed, it is somewhat odd that we have sections and we have "segments". The former is used by build-time linker and some debugging tools (e.g. if you want your program to map backtrace entries to line numbers). The later is for runtime stuff. Runtime linker and stack-unwinder/exceptions facility. I think "why" is because the latter is somewhat simpler and different enough. E.g. runtime relocations are quite different from build-time relocations. And unwinding has it's own set of "nice" details making it different enough from plain dwarf bits (which reside in some sections).