How to add a breakpoint to objc_exception_throw?
this was the answer from the brad larson on this SO question
If you add two breakpoints, you should be able to debug these exceptions. To do this, go to Run | Show | Breakpoints and create two global breakpoints (I do them globally because they are so useful in all my applications). The first should be named "objc_exception_throw" and its location should be "libobjc.A.dylib". The second should be "-[NSException raise]" and its location should be "CoreFoundation".
Now, if you start debugging your application with breakpoints enabled, it should break on the throw of these exceptions. You should then be able to see the chain of events that led to the exception within the debugger.
now in this answer i want to ask how do i add location mentioned???
Answer
I think Brad's answer is pretty clear; hopefully this can help if you're not finding it clear.
In Xcode, from the top menu click on Run > Show > Breakpoints. A new window pops up.
Select "global breakpoints" in the left hand menu. There should be a box on the right under the "Breakpoint" column with the text "Double-Click for symbol". Single-click in this box and type in "objc_exception_throw".
Then, single-click in the space next to "objc_exception_throw" under the "location" column. A box will appear for you to type in the location (in this case, "libobjc.A.dylib"). I've made a screenshot that will hopefully help:
