No debug symbol info on Linux?

I'm trying to debug my Swift app on Linux, but I don't seem to get debug symbols in lldb. Googling turns up little more than basic tutorials on using lldb. Any suggestions on what I should check? By default, Swift PM is supposed to build with debug info, but for whatever reason lldb isn't finding it. I'm executing it with lldb .build/armv7-unknown-linux-gnueabihf/debug/InfoDisplay.