The lldb Debugger

(2020)

Compile a binary with debugging information (minimally, -g):

🐚 $ clang -O0 -gfull -Wall -Wextra -pedantic hello.c -o hello

Run the binary in the lldb debugger:

🐚 $ lldb ./hello

lldb commands tend to follow this syntax:

<noun> <verb> [-options [option-value]] [argument [argument...]]

lldb has extensive help available.

(lldb) help
Debugger commands:
  apropos           -- List debugger commands related to a word or subject.
  breakpoint        -- Commands for operating on breakpoints (see 'help b' for shorthand.)
  bugreport         -- Commands for creating domain-specific bug reports.
  command           -- Commands for managing custom LLDB commands.
…

Use either lldb noun-verb commands or aliases to the equivalent gdb commands:

• thread step-in or step or s: next line (will step into any function call)
• thread step-over or next or n: next line in current thread (step over function call)
• thread step-out or finish: exit this scope

Set break point. Watch.

Links

• https://en.wikipedia.org/wiki/LLDB_(debugger)
• https://lldb.llvm.org/use/map.html
• https://lldb.llvm.org/use/tutorial.html
• https://clang.llvm.org/docs/ClangCommandLineReference.html#debug-information-generation
• https://developer.apple.com/library/archive/documentation/IDEs/Conceptual/gdb_to_lldb_transition_guide/document/lldb-command-examples.html
• https://towardsdatascience.com/an-introduction-to-debugging-in-c-and-lldb-part-i-e3c51991f83a
• https://towardsdatascience.com/an-introduction-to-debugging-in-c-and-lldb-part-i-e3c51991f83a