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 has not been ported (to enable remote debugging) Linux is nearing feature completeness with Darwin to debug x86_64 programs, and is partially working with i386 programs. ARM architectures on Linux are untested. For more details, see the Features by OS section below.

FreeBSD Status

LLDB on FreeBSD lags behind the Linux implementation but is improving rapidly. For more details, see the Features by OS section below.

Windows Status

LLDB on Windows is still under development, but already useful for i386 programs (x86_64 untested) built with DWARF debug information, including postmortem analysis of minidumps. 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. NetBSD support is under development.

Feature FreeBSD
(x86_64)		 Linux
(x86_64 and PPC64le)		 Mac OS X (i386/x86_64 and ARM/Thumb) Windows (i386)
Backtracing OK OK OK OK
Breakpoints
  • source-line
  • symbolic
  • C++ mangled names
  • module scoping
OK OK OK OK
C++11:
  • function access
  • template support
  • dynamic types
OK OK OK Unknown
Commandline lldb tool OK OK OK OK
Core file debugging OK (ELF) OK (ELF) OK (MachO) OK (Minidump)
Debugserver (remote debugging) Not ported Not ported OK Not ported
Disassembly OK OK OK OK
Expression evaluation Unknown Works with some bugs OK Works with some bugs
JIT debugging Unknown Symbolic debugging only Untested No
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")
Unknown Not applicable OK Not applicable
Process control
  • attach
  • continue
  • exec, execve...
  • fork
  • launch
  • status
Works, with some bugs OK (except exec*) OK OK
Public Python API OK (Python 2.7) OK (Python 2.7) OK (Python 2.7) OK (Python 3.5)
Registers (x86_64 and i386)
  • general purpose
  • floating point
  • exception state
  • SSE
  • AVX
GP and FP OK OK (except for exception state registers) OK OK (except for AVX support)
Symbol reading and object file introspection OK OK OK OK (no PDB yet)
Thread inspection and stepping OK OK OK OK
Watchpoints OK OK OK Not ported yet