UIKit Debug Mode

UIKit has hidden, useful debug flags for gesture/touch/animation logs, enable "InternalBuild" mode to switch them on.

fishhook

fishhook is a very simple library that enables dynamically rebinding symbols in Mach-O binaries running on iOS in the simulator and on device. This provides functionality that is similar to using DYLD_INTERPOSE on OS X. At Facebook, we've found it useful as a way to hook calls in libSystem for debugging/tracing purposes (for example, auditing for double-close issues with file descriptors).

Towards declarative touch interactions Slalom

A system with prototype implementation for concisely describing and implementing a class of touch interactions.

Xcode Consolation

Tips on using the Xcode debugging console (i.e. LLDB), notably on using regular expressions to add lots of breakpoints to trace execution.