The LLDB Debugger

Mac OS X Status

LLDB has matured a lot in the last year and can be used for C, C++ and Objective C development for x86_64, i386 and ARM debugging. The entire public API is exposed though a framework on Mac OS X which is used by Xcode, the lldb command line tool, and can also be used by Python. The entire public API is exposed through script bridging which allows LLDB to use an embedded Python script interpreter, as well as having a Python module named "lldb" which can be used from Python on the command line. This allows debug sessions to be scripted. It also allows powerful debugging actions to be created and attached to a variety of debugging workflows.

Linux Status

LLDB is improving on Linux. While the debugserver is not ported (to enable remote debugging) and there are some stability issues, most of the basic functionality, including the Python API and the commandline tool, are working on i386/x86_64 architectures. ARM architectures on Linux are untested. For more details, see the Features by OS section below.

Features by OS

The table below shows a summary of the features that are available on several platforms. In addition to Linux and Mac OS X, LLDB is also known to work on FreeBSD. Windows support is under development.

Feature Linux
(i386 and x86_64)
Mac OS X (i386/x86_64 and ARM/Thumb)
Backtracing OK OK
Breakpoints
  • source-line
  • symbolic
  • C++ mangled names
  • module scoping
OK except on C++ exception (catch/throw) OK
C++11:
  • function access
  • template support
  • dynamic types
OK OK
Commandline lldb tool OK OK
Debugserver (remote debugging) Not ported OK
Disassembly OK OK
Expression evaluation Works with some bugs OK
Objective-C 2.0:
  • printing properties
  • synthetic properties
  • expressions
  • KVO
  • dynamic types
  • dot syntax
  • runtime data
  • stepping into/over
  • printing the description of an object ("po")
Not applicable OK
Process control
  • launch
  • attach
  • continue
OK except attach-by-name OK
Public Python API OK OK
Script bridging OK OK
Symbol reading and object file introspection OK OK
Thread inspection and stepping OK for single thread (no multi-threaded support) OK
Watchpoints Broken OK