If you see a breakpoint in Xcode that is orange, or I actually think of it as semi-filled orange, that turns out to mean GDB could not resolve your symbol, and that breakpoint will not be hit. This condition seems to mysteriously appear, but it could turn out to be a bug in Xcode or something I mangled in my project file (I had a bad target rename experience, *shudder*). The only thing that seems to solve the problem concretely is to disable Load Symbols Lazily in Xcode Preferences Debugging tab. When I turn it off, I don't notice a performance hit, but I don't have a lot of source files or a large application, but your mileage may vary.
