I just upgraded Xcode to the latest (4.2 (4C199)) and my iPhone to iOS 5(9A334). I'm using Snow Leopard. While debugging, I noticed I don't get any information with my stack trace. It's just a list of addresses, there's no class or method information.
I figured maybe it was switching to LLDB, so I switched back to GDB. Nope, still a problem.
I hooked up an iPad running iOS 5, but a different version, one of the betas (9A5313e), and still an issue.
Then I hooked up an iPad 2 running iOS 4.3.5. Bam! A useful stack trace. So I went looking into the bowels of the /Developer folder, specifically into /Developer/Platforms/iPhoneOS.platform/DeviceSupport, like links on Google told me to, but the things I've tried aren't working.
How do I get symbols so my stack traces work in iOS 5?
This question deals with the same issue and has a straightforward workaround.
Apple seems to still have some issues to iron out with the latest XCode / iOS 5 combination.