[lldb-dev] LLDB Machine Interface Frontend

Colin Riley colin at codeplay.com
Tue May 20 04:51:43 PDT 2014


Hey Eran,

Comments inline.

On 19/05/2014 21:50, Eran Ifrah wrote:
> Thanks for your build Deepak, it starts without any crashes.
> However, the implementation is lacking, and I suspect that making it 
> work with any existing IDE that uses GDB/MI will take a lot of effort.
The implementation is certainly lacking, we stated that it's the initial 
commit and it's only tested with Eclipse. With Eclipse it works 
correctly. I should add at the moment only remote targets are supported. 
The amount of effort to get an existing GDB/MI interface up and running 
however is now drastically lower than previous!

>
> Few comments:
> On Windows, I use some extra normal commands that have no counter part 
> in the MI, such as "set new-console on" (which creates a new CMD.EXE 
> and redirects all the application's std[in|err|out]), ofc, this does 
> not work
Yeah, for those sorts of commands best bet is you add that yourself. 
Eclipse certainly doesn't use it, and that's our initial target.

>
> The replies from lldb-mi, are a bit different from gdb, for example, 
> consider this interaction between codelite (the IDE) and lldb-mi:
>
> Using gdbinit file: C:\Users\PC\AppData\Local\Temp\codelite_gdbinit.txt
> Current working dir: D:\src\TestArea\wxCrafterTester
> Launching gdb from : ./Debug
> Starting debugger  : C:\Users\PC\Desktop\MinSizeRel\lldb-mi.exe 
> --command="C:\Users\PC\AppData\Local\Temp\codelite_gdbinit.txt" 
> --interpreter=mi "./wxCrafterTester"
> DEBUG>>00000001-break-insert -f -t main
> DEBUG>>00000002-enable-pretty-printing
> Debug session started successfully!
> DEBUG>>00000003-exec-arguments
> DEBUG>>00000004-exec-run
> lldb-mi>>1^error,msg="Command 'break-insert'. Breakpoint 'main' invalid"
> 1^error,msg="Command 'break-insert'. Breakpoint 'main' invalid"
>
>
> Command: 00000001: -break-insert
> According to the docs, it can accept function name (its sole purpose 
> here is to place a temporary breakpoint at 'main' (hence, the "-t") ). 
> It seems like lldb-mi does not expect a function name but rather a 
> location? (did not try that)
-t and breakpoints on functions are certainly supported at this stage, 
the code is all there and we use it.  Will have to look at this one.
> Also, the reply from lldb-mi is different:
> codelite prepends a transaction ID (8 digits number with fixed length) 
> for each command it sends over to gdb, it is expecting gdb/lldb-mi to 
> reply with these exact 8 digits (including all padding zeros)
> this is not the case here (lldb-mi replied with '1' instead of '00000001')
Ack. The standard I guess does say any arrangement of digits, we'll get 
this one fixed :)

>
> After changing codelite's gdb settings (i.e. disabled the option to 
> temporarily break at main) I hit another obstacle: I can not place a 
> breakpoint:
>
> DEBUG>>00000005-break-insert -f 
> "\"D:/src/TestArea/wxCrafterTester/MainFrame.cpp:15\""
> ...
> and lldb-mi replied with:
>
> lldb-mi>>MI: Error: Command Args. Validation failed. Not all arguments 
> or options were recognized: 
> "\"D:/src/TestArea/wxCrafterTester/MainFrame.cpp:15\""
> MI: Error: Command Args. Validation failed. Not all arguments or 
> options were recognized: 
> "\"D:/src/TestArea/wxCrafterTester/MainFrame.cpp:15\""
> lldb-mi>>5^error,msg="Command 'break-insert'. Command Args. Validation 
> failed. Not all arguments or options were recognized: 
> "\"D:/src/TestArea/wxCrafterTester/MainFrame.cpp:15\"""
> 5^error,msg="Command 'break-insert'. Command Args. Validation failed. 
> Not all arguments or options were recognized: 
> "\"D:/src/TestArea/wxCrafterTester/MainFrame.cpp:15\"""
>
> At first I thought its because of the volume ("D:") part of the file 
> name, so I changed the settings to send file name without full path, 
> same error occured ...
> Also, it seems that when lldb-mi hits the first error it simply hangs 
> ( I don't see my application being launched )
We'll see if we can repo this sort of thing and have a look at it. We 
use it on windows  too so the volume being part of the file name 
shouldn't really matter.

>
> Some more observations:
> Commands that are not supported (and used by codelite IDE):
>
> // -exec-arguments
> DEBUG>>00000010-exec-arguments 1
> lldb-mi>>11^error,msg="Driver. Received command 
> '00000011-exec-arguments'. It was not handled. Command 
> 'exec-arguments' not in Command Factory"
>
> // -enable-pretty-printing
> DEBUG>>00000010-enable-pretty-printing
> lldb-mi>>10^done,supported="0"
>
> This was all tested on Windows 7, 64bit.
> Trying to debug an executable built with g++-4.8.1 32bit, (MinGW, no MSYS)
>
Yup, lots of commands still to write. At the moment though you can 
certainly use this frontend and it's usable on Eclipse, for remote 
targets anyway. Breakpoints, single stepping, local variables, stack 
traces are all there and supported. Obviously there will be issues given 
we're only testing on Eclipse.

As every 'standard' implementer knows, the only standard thing about all 
the implementations is that they are guaranteed to all be used in subtly 
different ways :)

Thanks for taking the time to check it out, this feedback is incredibly 
valuable. At the end of the day, we want to make sure the frontend will 
work with as many different IDEs as possible.

Cheers,

Colin

> Thanks for you work,
> Eran
>
>
>
> On Mon, May 19, 2014 at 2:26 PM, Deepak Panickal <deepak at codeplay.com 
> <mailto:deepak at codeplay.com>> wrote:
>
>     Hi Eran,
>
>     Here's the link to download the MinSizeRel build.
>     https://db.tt/CdvFKVcN
>
>     Thanks,
>     Deepak
>
>
>
>     On 16/05/2014 21:01, Eran Ifrah wrote:
>>
>>
>>
>>     On Fri, May 16, 2014 at 9:55 PM, Eran Ifrah <eran.ifrah at gmail.com
>>     <mailto:eran.ifrah at gmail.com>> wrote:
>>
>>
>>
>>
>>         On Fri, May 16, 2014 at 8:23 PM, Deepak Panickal
>>         <deepak at codeplay.com <mailto:deepak at codeplay.com>> wrote:
>>
>>             Hi Eran,
>>
>>             I tried it here with a Debug build and a MinSizeRel
>>             build, but no crashes.
>>
>>             Did you try to launch it from an IDE or simply ran it?
>>
>>         I tried it from the command line
>>
>>         FYI:
>>         I am using Windows 7 (64), Visual Studio 2013 (express edition)
>>         Can you upload your lldb-mi.exe / liblldb.dll somewhere so I
>>         could try it here and see if its a problem with my build?
>>
>>             Could you please try a debug build?
>>
>>         Will do
>>
>>     here is the backtrace from the crash (it crashes on a va_copy()
>>     call... arg) :
>>
>>          msvcr120d.dll!5ccefb53()    Unknown
>>          [Frames below may be incorrect and/or missing, no symbols
>>     loaded for msvcr120d.dll]
>>          [External Code]
>>     > lldb-mi.exe!CMIUtilString::FormatPriv(const CMIUtilString &
>>     vrFormat, char * vArgs) Line 114    C++
>>     lldb-mi.exe!CMIUtilString::Format(const CMIUtilString &
>>     vrFormating, ...) Line 139    C++
>>     lldb-mi.exe!CMIDriverMgr::GetAppVersion() Line 577    C++
>>          lldb-mi.exe!CMICmnLog::Initialize() Line 83    C++
>>     lldb-mi.exe!MI::ModuleInit<CMICmnLog>(const int vErrorResrcId,
>>     bool & vwrbOk, CMIUtilString & vwrErrMsg) Line 50 C++
>>     lldb-mi.exe!CMIDriverMgr::Initialize() Line 82    C++
>>          lldb-mi.exe!DriverSystemInit() Line 199    C++
>>          lldb-mi.exe!main(int argc, const char * * argv) Line 317    C++
>>          [External Code]
>>
>>     And for your convenience, here is the "Locals" view during the crash:
>>     vrFormat    "%s\n%s\n%s"    const CMIUtilString &
>>     vArgs    0x00bdf334 "ÌÌÌÌ| \x15"    char *
>>     argsCpy    0x00bdf334 "ÌÌÌÌ| \x15"    char *
>>     nFinal    0    int
>>     pFormatted    unique_ptr 37 '%' std::unique_ptr<char
>>     [0],std::default_delete<char [0]> >
>>     n    16    int
>>     strResult    ""    CMIUtilString
>>
>>     Hope it will give you a hint
>>
>>
>>             We'll look into it more to see if we can find something.
>>
>>             Thanks,
>>             Deepak
>>
>>
>>             On 16/05/2014 17:04, Eran Ifrah wrote:
>>>             Hi Deepak,
>>>
>>>             I have just updated and rebuilt the tree on Windows
>>>             Starting lldb-mi.exe -> instantly crashes
>>>             for comparison, starting lldb.exe it starts normally
>>>             without any crash
>>>
>>>             I built it using VS2013, I selected the 'MinSizeRel'
>>>             build configuration
>>>             Unfortunately, running it under VS, gives a useless
>>>             backtrace (only addresses)
>>>
>>>             I could try and build it with debug info, but it just
>>>             takes too much time :D
>>>
>>>             Eran
>>>
>>>
>>>
>>>
>>>             On Fri, May 16, 2014 at 6:50 PM, <jingham at apple.com
>>>             <mailto:jingham at apple.com>> wrote:
>>>
>>>                 Excellent!  Again, thanks for working on this.
>>>
>>>                 Jim
>>>
>>>                 On May 16, 2014, at 4:15 AM, Deepak Panickal
>>>                 <deepak at codeplay.com <mailto:deepak at codeplay.com>>
>>>                 wrote:
>>>
>>>                 > Thanks Jim, have just committed it. Yeah, it works
>>>                 with the GDB/MI interface.
>>>                 >
>>>                 > There's no GPL code, it's all written from scratch.
>>>                 > Not all MI commands have been implemented yet,
>>>                 however it should be enough to set breakpoints, view
>>>                 locals.
>>>                 > We're working on adding more commands for
>>>                 viewing/modifying registers, memory etc.
>>>                 >
>>>                 > It'll be great if more people from the community
>>>                 can use and test it with other GUIs!
>>>                 >
>>>                 > Thanks,
>>>                 > Deepak
>>>                 >
>>>                 >
>>>                 > On 15/05/2014 18:57, jingham at apple.com
>>>                 <mailto:jingham at apple.com> wrote:
>>>                 >> First off, thanks for doing this, that is great!
>>>                  If this also works with the gdb-mi mode, you will
>>>                 make our emacs friends happy as well.
>>>                 >>
>>>                 >> If this is just an independent tool that doesn't
>>>                 touch the core lldb sources (and doesn't use
>>>                 anything directly from the gdb MI implementation,
>>>                 since we don't want to mix GPL'ed code in with
>>>                 lldb), I see no reason not to just check it in now,
>>>                 and then iterate on it in situ.  That is much easier
>>>                 than handing around patch files, and since there's
>>>                 no chance it will interfere with anybody working on
>>>                 parts of lldb that existed before the patch, can't
>>>                 do any harm.  I spoke to GregC and he agrees this is
>>>                 a reasonable course.
>>>                 >>
>>>                 >> Again, thanks for working on this.
>>>                 >>
>>>                 >> Jim
>>>                 >>
>>>                 >>
>>>                 >> On May 15, 2014, at 10:17 AM, Deepak Panickal
>>>                 <deepak at codeplay.com <mailto:deepak at codeplay.com>>
>>>                 wrote:
>>>                 >>
>>>                 >>> Hi Abid,
>>>                 >>>
>>>                 >>> Thank you, I have attached the zipped patch.
>>>                 >>> You might have to the change the triple in
>>>                 tools/lldb-mi/MICmnConfig.h for your target.
>>>                 >>>
>>>                 >>> Please let me know if you have any
>>>                 comments/suggestions.
>>>                 >>>
>>>                 >>> Thanks,
>>>                 >>> Deepak
>>>                 >>>
>>>                 >>> On 15/05/2014 17:10, Abid, Hafiz wrote:
>>>                 >>>> Hi Deepak,
>>>                 >>>> I can help review/test it when you post the patch.
>>>                 >>>>
>>>                 >>>> Thanks,
>>>                 >>>> Abid
>>>                 >>>>
>>>                 >>>>> -----Original Message-----
>>>                 >>>>> From: lldb-dev-bounces at cs.uiuc.edu
>>>                 <mailto:lldb-dev-bounces at cs.uiuc.edu>
>>>                 [mailto:lldb-dev-bounces at cs.uiuc.edu
>>>                 <mailto:lldb-dev-bounces at cs.uiuc.edu>]
>>>                 >>>>> On Behalf Of Deepak Panickal
>>>                 >>>>> Sent: 15 May 2014 12:14
>>>                 >>>>> To: lldb-dev at cs.uiuc.edu
>>>                 <mailto:lldb-dev at cs.uiuc.edu>
>>>                 >>>>> Subject: [lldb-dev] LLDB Machine Interface
>>>                 Frontend
>>>                 >>>>>
>>>                 >>>>> Hi,
>>>                 >>>>>
>>>                 >>>>> We have an MI (Machine Interface) frontend to
>>>                 LLDB which works out of the
>>>                 >>>>> box with Eclipse, and likely will work with
>>>                 other GUI's based on the GDB/MI
>>>                 >>>>> interface. It's been tested on Linux and Windows.
>>>                 >>>>>
>>>                 >>>>> It's ready to upstream and has been developed
>>>                 as an independent tool
>>>                 >>>>> residing in the LLDB tools folder. It's based
>>>                 on the LLDB public API without
>>>                 >>>>> any changes to LLDB internals.
>>>                 >>>>>
>>>                 >>>>> The patch is quite large as there are many new
>>>                 files.
>>>                 >>>>> How should we go about upstreaming? Should I
>>>                 create a diff review as
>>>                 >>>>> usual?
>>>                 >>>>>
>>>                 >>>>> Thanks,
>>>                 >>>>> Deepak
>>>                 >>>>> _______________________________________________
>>>                 >>>>> lldb-dev mailing list
>>>                 >>>>> lldb-dev at cs.uiuc.edu <mailto:lldb-dev at cs.uiuc.edu>
>>>                 >>>>> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
>>>                 >>>
>>>                 <lldb-mi-driver.patch.bz2>_______________________________________________
>>>                 >>> lldb-dev mailing list
>>>                 >>> lldb-dev at cs.uiuc.edu <mailto:lldb-dev at cs.uiuc.edu>
>>>                 >>> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
>>>                 >
>>>
>>>                 _______________________________________________
>>>                 lldb-dev mailing list
>>>                 lldb-dev at cs.uiuc.edu <mailto:lldb-dev at cs.uiuc.edu>
>>>                 http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
>>>
>>>
>>>
>>>
>>>             -- 
>>>             Eran Ifrah
>>>             Author of codelite, a cross platform open source C/C++
>>>             IDE: http://www.codelite.org
>>>             wxCrafter, a wxWidgets RAD:
>>>             http://wxcrafter.codelite.org
>>>             <http://wxcrafter.codelite.org>
>>
>>
>>
>>
>>         -- 
>>         Eran Ifrah
>>         Author of codelite, a cross platform open source C/C++ IDE:
>>         http://www.codelite.org
>>         wxCrafter, a wxWidgets RAD: http://wxcrafter.codelite.org
>>         <http://wxcrafter.codelite.org>
>>
>>
>>
>>
>>     -- 
>>     Eran Ifrah
>>     Author of codelite, a cross platform open source C/C++ IDE:
>>     http://www.codelite.org
>>     wxCrafter, a wxWidgets RAD: http://wxcrafter.codelite.org
>>     <http://wxcrafter.codelite.org>
>
>
>
>
> -- 
> Eran Ifrah
> Author of codelite, a cross platform open source C/C++ IDE: 
> http://www.codelite.org
> wxCrafter, a wxWidgets RAD: http://wxcrafter.codelite.org 
> <http://wxcrafter.codelite.org>
>
>
> _______________________________________________
> lldb-dev mailing list
> lldb-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev

-- 
- Colin Riley
Games Technology Director

Codeplay Software Ltd
45 York Place, Edinburgh, EH1 3HP
Tel: 0131 466 0503
Fax: 0131 557 6600
Website: http://www.codeplay.com
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