[lldb-dev] Refactoring in LLDB Windows Plugin

[Stephane Sezer via lldb-dev]

Yeah, we have to fake the numbers, we have some sort of dummy mapping
that converts Windows events to the UNIX equivalent that makes the
most sense. It's kind of dumb, but that's the only thing that LLDB or
gdb support.

First half of the conversion is here:
https://github.com/facebook/ds2/blob/master/Sources/Target/Windows/Thread.cpp#L110
and the second half is here:
https://github.com/facebook/ds2/blob/master/Sources/GDBRemote/Structures.cpp#L357

On Thu, Dec 1, 2016 at 3:00 AM, Pavel Labath <labath at google.com> wrote:
> I'm curious, can you share how did you deal with the fact that the
> gdb-remote protocol is very signal-centric? E.g. every stop-reply ($T) has
> to have a specific signal associated with it, and some signals have special
> meaning in lldb. Do you just fake the signal numbers when you need to? Or is
> the situation not as bad as I imagine?
>
> cheers,
> pl
>
> On 1 December 2016 at 07:57, Stephane Sezer via lldb-dev
> <lldb-dev at lists.llvm.org> wrote:
>>
>> For what it's worth, we've been using lldb with ds2 to do remote
>> debugging on Windows (x86) and Windows Phone (arm) and the lldb side
>> of things works well with remote Windows targets. Besides porting
>> lldb-server to Windows there shouldn't be any extra effort on the lldb
>> side to do what Greg is talking about.
>>
>> On Wed, Nov 30, 2016 at 9:35 AM, Greg Clayton via lldb-dev
>> <lldb-dev at lists.llvm.org> wrote:
>> >
>> >> On Nov 29, 2016, at 10:16 PM, Zachary Turner <zturner at google.com>
>> >> wrote:
>> >>
>> >> What would it take to make it so that local and remote process plugins
>> >> use the same exact interface?  I mean in theory they're doing the same
>> >> thing, just on a different machine.  If they shared an identical interface
>> >> then you could hook the lldb-server up to it and it would work either
>> >> locally or remotely.
>> >>
>> >> What was the original motivation for having the api design of remote
>> >> and local process plugins diverge?
>> >
>> > The plan was always do remote so we are always using one thing. We
>> > started off thinking we wanted to have a native plug-in and a remote GDB
>> > server, but when we found we didn't have serious performance issues we went
>> > the lldb-server/debugserver route for everything on our end. lldb-server
>> > uses NativeProcess and NativeThread as base classes that must be subclassed
>> > and we would make a ProcessNative plug-in that used the native compiled
>> > version of these (like lldb-server does), but then we have two code paths to
>> > test: native and remote. So we either have to run twice the number of tests,
>> > one local and one remote, so we can make sure native and remote work
>> > correctly, or we just go one route. What would tend to happen is we would
>> > 99.9% of people would do local debugging only and all bugs submitted would
>> > mostly be bugs with the native implementation and remote would suffer and
>> > become neglected. GDB had two different code paths for these so remote
>> > really did suffer and we evolved to use remote only on all our systems.
>> > Another nice reason for this is you can save the GDB remote packet log
>> > traffic when you do encounter a bug and see exactly what happened when a bug
>> > happened.
>> >
>> > So due to history, we started thinking we would need both native and
>> > remote plug-ins, but we migrated over time to just one solution for simpler
>> > testing, ensuring remote debugging is rock solid since it is always used for
>> > local debugging, and for the convenience of being able to completely lop all
>> > traffic to/from the process with the GDB remote logs.
>> >
>> > Greg
>> >
>> > _______________________________________________
>> > lldb-dev mailing list
>> > lldb-dev at lists.llvm.org
>> > http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
>>
>>
>>
>> --
>> Stephane Sezer
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>
>



-- 
Stephane Sezer