Using LLDB
Scripting LLDB
Developing LLDB
External Links
The embedded python interpreter can be accessed in a variety of ways fromwithin LLDB. The easiest way is to use the lldb command script with noarguments at the lldb command prompt:
(lldb)scriptPythonInteractiveInterpreter.Toexit,type'quit()','exit()'orCtrl-D.>>>2+35>>>hex(12345)'0x3039'>>>
This drops you into the embedded python interpreter. When running under thescript command, lldb sets some convenience variables that give you quick accessto the currently selected entities that characterize the program and debuggerstate. In each case, if there is no currently selected entity of theappropriate type, the variable’s IsValid method will return false. Thesevariables are:
Variable | Type | Equivalent | Description |
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| Contains the debugger object whose |
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| Contains the currently selected target - for instance the one made with the |
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| Contains the process of the currently selected target. The |
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| Contains the currently selected thread. The |
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| Contains the currently selected stack frame. The |
While extremely convenient, these variables have a couple caveats that youshould be aware of. First of all, they hold the values of the selected objectson entry to the embedded interpreter. They do not update as you use the LLDBAPI’s to change, for example, the currently selected stack frame or thread.
Moreover, they are only defined and meaningful while in the interactive Pythoninterpreter. There is no guarantee on their value in any other situation, henceyou should not use them when defining Python formatters, breakpoint scripts andcommands (or any other Python extension point that LLDB provides). For thelatter you’ll be passed anSBDebugger,SBTarget,SBProcess,SBThread orSBFrame instance and you can use the functions from the “Equivalent” columnto navigate between them.
As a rationale for such behavior, consider that lldb can run in a multithreadedenvironment, and another thread might call the “script” command, changing thevalue out from under you.
To get started with these objects and LLDB scripting, please note that almostall of the lldb Python objects are able to briefly describe themselves when youpass them to the Python print function:
(lldb)scriptPythonInteractiveInterpreter.Toexit,type'quit()','exit()'orCtrl-D.>>>print(lldb.debugger)Debugger(instance:"debugger_1",id:1)>>>print(lldb.target)a.out>>>print(lldb.process)SBProcess:pid=58842,state=stopped,threads=1,executable=a.out>>>print(lldb.thread)thread#1: tid = 0x2265ce3, 0x0000000100000334 a.out`main at t.c:2:3, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1>>>print(lldb.frame)frame#0: 0x0000000100000334 a.out`main at t.c:2:3