Cocoa: Break on every method call?

Question

Often when debugging, it's important for me to know what methods of a class are being called in what order. The naive solution (that I've been using thus far) is to pop an NSLog at the top of each method. But this is time consuming, repetitive, ugly, and makes my code look juvenile if I forget to remove the logs after debugging.

A cleaner solution is to set breakpoints on each of my methods, configure their actions to issue the debugger command: po NSStringFromSelector(_cmd) and set them to automatically continue. This is prettier and saves me from having to remember to remove all those NSLogs, but is no less repetitive or time consuming.

What I really want is a way to set a symbolic breakpoint that breaks on every method (of a class? Of a module?). Any debugging/runtime masters have a solution or tips on where to start looking?

Answer 1

All Objective-C method calls go through one of the C runtime calls objc_msgSend, objc_msgSend_stret, objc_msgSendSuper and objc_msgSendSuper_stret per the 'Sending Messages' section of the Objective-C Runtime Reference. So you should be able to trap those, and give them actions to log the relevant parts of the first two parameters (it's target and selector for the normal sends, a struct describing the superclass that contains both the target and the class type for super calls).

Answer 2

Use a logging system like Log4Cocoa. Logging the method, line number, and file from which it was called is a basic function of such logging systems.

Each logging call is given a detail level, specifying under what conditions it should log. You would then set the detail level to get the desired amount of information. Products built for release, for examples, would only log errors and perhaps warnings; debug level would log everything.