LLDB from the command line

Before IDEs and all current eye-candy stuff, everything was done like this:

• Compile a sample.cpp program with debug symbols

  $ clang++ -g sample.cpp
  

• Star the debugger

  $ lldb
  

• Create a target to start the debug session

  $ target create a.out
  

• Setup your breakpoints

  # breakpoing set --file sample.cpp --line 7
  $ b sample.cpp:7
  

• List breakpoints

  $ breakpoint list
  

• Set a condition to a preakpoint (conditional breakpoint). Use list to get the breakpoint number and replace it with N.

  $ condition N (int)[[myObj name] isEqualToString:@"Bar"]
  

• Run the target

  $ run a.out
  

• Step in

  $ s
  

• Step over (next)

  $ n
  

• Print the stack trace

  $ st
  

From now do as usual...
More Commands on lldb-gdb table

2016/01/23 Example: Debug Nodejs

We download nodejs from github and build it with the DEBUG configuration

git clone https://github.com/nodejs/node.git
cd node/
./configure
make -C out BUILDTYPE=Debug # I got this information by reading the Makefile :)

At this point we have a binary with debug information in out/Debug/. Let's start the lldb on it

cd out/Debug
lldb

On lldb, create a target, set some breakpoints and run it

(lldb) target create node
(lldb) b /Users/ignacio/Documents/github/node/src/node.cc:4127
(lldb) run node /Users/ignacio/Downloads/node-js-bug--debug-gets-stuck-on-two-c-commands/perlito5.js

Now keep on debugging :)