A.
Appendix A: LLDB Cheatsheet
Written by Derek Selander
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A cheatsheet for commands and ideas on how to use LLDB.
Getting help
(lldb) help
List all commands and aliases.
(lldb) help po
Get help documentation for po (expression) command.
(lldb) help break set
Get help documentation for breakpoint set.
(lldb) apropos step-in
Search through help documentation containing step-in.
Finding code
(lldb) image lookup -rn UIAlertController
Look up all code containing UIAlertController that’s compiled or loaded into an executable.
(lldb) image lookup -rn (?i)hosturl
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(lldb) image lookup -rn 'UIViewController\ set\w+:\]'
(lldb) image lookup -rn . Security
(lldb) image lookup -a 0x10518a720
(lldb) image lookup -s mmap
Breakpoints
(lldb) b viewDidLoad
Creates a breakpoint on all methods named viewDidLoad for both Swift and Objective-C.
(lldb) b setAlpha:
(lldb) b -[CustomViewControllerSubclass viewDidLoad]
(lldb) rbreak CustomViewControllerSubclass.viewDidLoad
(lldb) breakpoint delete
(lldb) breakpoint delete 2
(lldb) breakpoint list
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(lldb) rbreak viewDid
(lldb) rbreak viewDid -s SwiftRadio
(lldb) rbreak viewDid(Appear|Disappear) -s SwiftHN
(lldb) rb "\-\[UIViewController\ set" -s UIKit
(lldb) rb . -s SwiftHN -o 1
(lldb) rb . -f ViewController.m
Expressions
(lldb) po "hello, debugger"
Prints "hello, debugger" regardless of the debugging context.
(lldb) expression -lobjc -O -- [UIApplication sharedApplication]
(lldb) expression -lswift -O -- UIApplication.shared
(lldb) b getenv
(lldb) expression -i0 -- getenv("HOME")
(lldb) expression -u0 -O -- [UIApplication test]
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(lldb) expression -p -- NSString *globalString = [NSString stringWithUTF8String: "Hello, Debugger"];
(lldb) po globalString
Hello, Debugger
(lldb) expression -g -O -lobjc -- [NSObject new]
Stepping
(lldb) thread return false
Return early from code with false.
(lldb) thread step-in
(lldb) s
(lldb) thread step-over
(lldb) n
(lldb) thread step-out
(lldb) finish
(lldb) thread step-inst
(lldb) ni
GDB formatting
(lldb) p/x 128
Print value in hexadecimal.
(lldb) p/d 128
(lldb) p/t 128
(lldb) p/a 128
(lldb) x/gx 0x000000010fff6c40
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(lldb) x/wx 0x000000010fff6c40
Memory
(lldb) memory read 0x000000010fff6c40
Read memory at address 0x000000010fff6c40.
(lldb) po id $d = [NSData dataWithContentsOfFile:@"..."]
(lldb) mem read `(uintptr_t)[$d bytes]` `(uintptr_t)[$d bytes] + (uintptr_t)[$d length]` -r -b -o /tmp/file
Registers & assembly
(lldb) register read -a
Display all registers on the system.
(lldb) register read rdi rsi
(lldb) register write rsi 0x0
(lldb) register write rflags `$rflags ^ 64`
(lldb) register write rflags `$rflags | 64`
(lldb) register write rflags `$rflags & ~64`
(lldb) register write pc `$pc+4`
(lldb) disassemble
(lldb) disassemble -p
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(lldb) disassemble -b
(lldb) disassemble -n '-[UIViewController setTitle:]'
(lldb) disassemble -a 0x000000010b8d972d
Modules
(lldb) image list
List all modules loaded into the executable’s process space.
(lldb) image list -b
(lldb) process load /Path/To/Module.framework/Module