Q:

objc_msgsend in iPhone disassembly

I'm trying to figure out what method is being called in the following bit of disassembly but I have no idea what's happening. I understand that with objc_msgsend the first argument is the object pointer and the second is the selector (so r0 and r1). But I'm having trouble figuring this out. Here's just the section before the call where r1 is being configured:
00042e48  f64731bc    movw    r1, 0x7bbc
00042e4c    f2c0011f    movt    r1, 0x1f
00042e50        4479    add r1, pc
00042e52        6809    ldr r1, [r1, #0]
00042e54    f1c2e84a    blx 0x204eec    @ symbol stub for: _objc_msgSend
From my understanding of this the first two lines would make r1 equal 1f007bbc but what can I do from there?
Edit: Also, what does adding r1 and the pc do? And what does the line after that do? And I've tried "otool -o SpringBoard" but that doesn't give me the selectors (don't know what it is but it isn't what I'm looking for) 
Edit 2: Actaully, -o does give me all the methods (I got loads of random methods from the headers and searched them in the terminal window and they were there). However a search for "1f007bbc" didn't return anything. Did I get the number right? 

A:

If you have access to the debugger, you should be able to p (char*) 1f007bbc and it'll print the selector name.
The selectors are generally constant and, thus, you should be able to extract this from the binary, too, by taking apart the mach-o.

