What role does gdb/remote.c play?

[Triple Yang]

2011/8/15 Petr Hluzín <petr.hluzin@gmail.com>:
> On 15 August 2011 17:09, Triple Yang <triple.yang@gmail.com> wrote:
>> 2011/8/15 Pedro Alves <pedro@codesourcery.com>:
>>> On Monday 15 August 2011 12:51:11, Triple Yang wrote:
>>>
>>>> Then, if I want to create a new remote target, should I just modify
>>>> remote.c or reuse codes in it?
>>>
>>> I don't know what your new target does, so I can't answer that for you.
>>>
>>>> How do I map command 'target remote' to the new target I created?
>>>
>>> You don't.  Do you _really_ need to implement a new target in gdb?
>>> Why not teach the remote end the RSP instead?  Then you can
>>> use "target remote", without adding new code to gdb.
>>>
>>
>> Yes, because I am trying porting GDB to a new architecture prototype.
>> Implementing a new target seems to be the only way to achieve the
>> purpose.
>
> If your users want to debug programs running on a remote
> machine/device then you can either:
> A: override "target remote" (or other target) implementation in GDB
> and use custom communication or
> B: use GDB's remote protocol, modify gdbserver sources and write your
> own handling or
> C: use GDB's remote protocol and write your own parsing and handling
>
> The option A is not recommended (see Pedro Alves) because it either
> means you will be distributing your own GDB or be stuck to FSF release
> schedule. Also users of older gdbs will not be able to connect (plus
> users will get misleading diagnostic). And there is a lot of code in
> gdb and many ways to get lost.
>
> For options B and C the user would type "target remote" and it will
> behave the way users expect from other archs (as the case may be),
> what tutorials describe and what IDEs do well.
>

So in option B or C, will reusing codes in remote.c be satisfying?
(Thus I may save some time in writing codes parsing/wrapping RSP
packets.)

>> To "teach the remote end the RSP instead", what needs to be done?
>
> On remote system do create a listening TCP socket and implement
> processing the remote protocol commands [1]. The gdbserver does that
> for several architectures and can serve as an inspiration.
>
> [1] http://sourceware.org/gdb/current/onlinedocs/gdb/Remote-Protocol.html
>
> --
> Petr Hluzin
>

Best regards.