[lldb-dev] run after process stop using python API

Fri Jun 28 13:02:24 PDT 2013

Two questions:

1. If the default is to have an input reader for the command interpreter, can I just call DispatchInput to run a command?  That doesn't seem to work for me.
2. If 'run' pushes a new InputReader, how should my python code be notified of that?  There is no event on the debugger's default listener.

Ben

> -----Original Message-----
> From: Greg Clayton [mailto:gclayton at apple.com]
> Sent: Friday, June 28, 2013 1:45 PM
> To: Langmuir, Ben
> Cc: Filipe Cabecinhas; lldb-dev at cs.uiuc.edu
> Subject: Re: [lldb-dev] run after process stop using python API
> 
> DispatchInput is for you to give input into the debugger which will be fed to
> the top level InputReader.
> 
> LLDB has input readers that funnel one stdin into which ever input reader is
> on the top. LLDB has many input readers:
> - the command interpreter
> - the stdin for the process
> - the embedded python script interpreter
> - multi-line code expressions when you type "expression<RETURN>"
> - multi-line python expressions for breakpoints and such
> 
> By default the command interpreter is the one and only input reader.
> 
> (lldb)
> 
> The input read stack looks like:
> 1 - command interpreter
> 
> 
> If you then type "script":
> 
> (lldb) script
> Python Interactive Interpreter. To exit, type 'quit()', 'exit()' or Ctrl-D.
> >>>
> 
> Now the input read stack looks like:
> 1 - python interactive interpreter
> 2 - command interpreter
> 
> Any data passed into DispatchInput() will be passed to the top level
> interpreter until it decides it should be removed from the stack (by typing
> "quit()" in the python interactive interpreter).
> 
> So think of DispatchInput as supplying stdin to LLDB and LLDB will route that
> information as needed to the correct interpreter.
> 
> 
> HandleCommand always goes to the command interpreter, no matter what
> input reader is being used.
> 
> Greg Clayton
> 
> On Jun 28, 2013, at 6:45 AM, "Langmuir, Ben" <ben.langmuir at intel.com>
> wrote:
> 
> > Is there documentation for DispatchInput somewhere? There are no
> comments in SBDebugger.h about it, and none of the examples seem to use
> it.  What is the difference between DispatchInput and HandleCommand?
> >
> > Ben
> >
> >> -----Original Message-----
> >> From: filcab at gmail.com [mailto:filcab at gmail.com] On Behalf Of Filipe
> >> Cabecinhas
> >> Sent: Thursday, June 27, 2013 2:26 PM
> >> To: Langmuir, Ben
> >> Cc: Enrico Granata; lldb-dev at cs.uiuc.edu
> >> Subject: Re: [lldb-dev] run after process stop using python API
> >>
> >> Hi Ben,
> >>
> >> The problem you seem to be having is not taking into account the
> >> output of the debugger.
> >> When you send the “run” command, it pushes an InputReader (I think)
> >> and asks you if you're sure you want to continue.
> >> If you take this into account, you can print that message on your
> >> user's console, and the DispatchInput() with the reply. Could you try
> >> that and see if it works?
> >> If it doesn't work, you may find it necessary to do something like
> >> the driver does, where you give the debugger an stdin and stdout and
> >> use those for all input/output from/to the debugger itself.
> >>
> >> Your UI over lldb should always try to use the SB* API, and never
> >> HandleCommand (except for direct user input, but even then,
> >> DispatchInput or the debugger's stdin should be possible to use, so
> >> you don't need more than one input path).
> >>
> >> Regards,
> >>
> >>  Filipe
> >>
> >>
> >> On Thu, Jun 27, 2013 at 5:40 AM, Langmuir, Ben
> >> <ben.langmuir at intel.com>
> >> wrote:
> >>> Just being able to re-run the target at any (reasonable) point.  I’m
> >>> working on a frontend for lldb using the python api, and I’m using
> >>> the command interpreter to deal with user input.
> >>>
> >>>
> >>>
> >>> Thanks,
> >>>
> >>>
> >>>
> >>> Ben
> >>>
> >>>
> >>>
> >>> From: Enrico Granata [mailto:egranata at apple.com]
> >>> Sent: Wednesday, June 26, 2013 5:15 PM
> >>> To: Langmuir, Ben
> >>> Cc: Malea, Daniel; lldb-dev at cs.uiuc.edu
> >>>
> >>>
> >>> Subject: Re: [lldb-dev] run after process stop using python API
> >>>
> >>>
> >>>
> >>> $ ./lldb /bin/ls
> >>>
> >>> Current executable set to '/bin/ls' (x86_64).
> >>>
> >>> (lldb) sett set auto-confirm true
> >>>
> >>> (lldb) b malloc
> >>>
> >>> Breakpoint 1: 2 locations.
> >>>
> >>> (lldb) r
> >>>
> >>> Process 48551 launched: '/bin/ls' (x86_64)
> >>>
> >>> Process 48551 stopped
> >>>
> >>> * thread #1: tid = 0x5edda, 0x00007fff906cd8f9
> >>> libsystem_malloc.dylib`malloc, stop reason = breakpoint 1.2
> >>>
> >>>    frame #0: 0x00007fff906cd8f9 libsystem_malloc.dylib`malloc
> >>>
> >>> libsystem_malloc.dylib`malloc:
> >>>
> >>> -> 0x7fff906cd8f9:  pushq  %rbp
> >>>
> >>>   0x7fff906cd8fa:  movq   %rsp, %rbp
> >>>
> >>>   0x7fff906cd8fd:  pushq  %rbx
> >>>
> >>>   0x7fff906cd8fe:  pushq  %rax
> >>>
> >>> (lldb) r
> >>>
> >>> Process 48554 launched: '/bin/ls' (x86_64)
> >>>
> >>> Process 48554 stopped
> >>>
> >>> * thread #1: tid = 0x5edf2, 0x00007fff906cd8f9
> >>> libsystem_malloc.dylib`malloc, stop reason = breakpoint 1.2
> >>>
> >>>    frame #0: 0x00007fff906cd8f9 libsystem_malloc.dylib`malloc
> >>>
> >>> libsystem_malloc.dylib`malloc:
> >>>
> >>> -> 0x7fff906cd8f9:  pushq  %rbp
> >>>
> >>>   0x7fff906cd8fa:  movq   %rsp, %rbp
> >>>
> >>>   0x7fff906cd8fd:  pushq  %rbx
> >>>
> >>>   0x7fff906cd8fe:  pushq  %rax
> >>>
> >>>
> >>>
> >>> You want to set the auto-confirm lldb setting to true before you
> >>> issue the second run
> >>>
> >>>
> >>>
> >>> What exactly are you trying to achieve, if you can discuss it?
> >>>
> >>>
> >>>
> >>> Enrico Granata
> >>> 📩 egranata@.com
> >>> ☎️ 27683
> >>>
> >>>
> >>>
> >>> On Jun 26, 2013, at 2:10 PM, Langmuir, Ben <ben.langmuir at intel.com>
> >> wrote:
> >>>
> >>>
> >>>
> >>> How do I turn off the prompt setting?
> >>>
> >>> Also, continue isn’t what I want – I really do want to re-run the
> >>> program from the start.
> >>>
> >>>
> >>>
> >>> Ben
> >>>
> >>>
> >>>
> >>> From: Malea, Daniel
> >>> Sent: Wednesday, June 26, 2013 5:08 PM
> >>> To: Langmuir, Ben; lldb-dev at cs.uiuc.edu
> >>> Subject: Re: [lldb-dev] run after process stop using python API
> >>>
> >>>
> >>>
> >>> 'run' is a GDB alias for process launch. If a process is already
> >>> running, the command interpreter may be waiting for confirmation
> >>> from the user that it's OK to restart the process (unless you turned
> >>> off the prompt setting beforehand)... You probably want to issue a
> >>> "continue" command to restart the process.
> >>>
> >>>
> >>>
> >>>
> >>>
> >>> Cheers,
> >>>
> >>> Dan
> >>>
> >>>
> >>>
> >>> From: <Langmuir>, Ben Langmuir <ben.langmuir at intel.com>
> >>> Date: Wednesday, 26 June, 2013 4:57 PM
> >>> To: "lldb-dev at cs.uiuc.edu" <lldb-dev at cs.uiuc.edu>
> >>> Subject: [lldb-dev] run after process stop using python API
> >>>
> >>>
> >>>
> >>> I’m trying to use the ‘run’ command from the python API when my
> >>> process has stopped at a breakpoint, but it appears to hang.  Script
> >> attached.
> >>>
> >>>
> >>>
> >>> i.HandleCommand('b main', res)
> >>>
> >>> i.HandleCommand('r', res) -> runs to breakpoint correctly
> >>>
> >>> i.HandleCommand('r', res) -> appears to hang
> >>>
> >>>
> >>>
> >>> This seems like a bug, but I thought I would ask in case the
> >>> interpreter was waiting for some kind of input I wasn’t providing…
> >>> I’m running on Linux, and haven’t had a chance to try OS X yet.
> >>>
> >>>
> >>>
> >>> Ben
> >>>
> >>> _______________________________________________
> >>> lldb-dev mailing list
> >>> lldb-dev at cs.uiuc.edu
> >>> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
> >>>
> >>>
> >>>
> >>>
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> >>>
> >
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