MI *stopped versus silent breakpoint

teawater teawater@gmail.com
Thu Feb 5 15:43:00 GMT 2009


On Thu, Feb 5, 2009 at 17:35, Vladimir Prus <vladimir@codesourcery.com> wrote:
> teawater wrote:
>
>> On Thu, Feb 5, 2009 at 17:25, Vladimir Prus <vladimir@codesourcery.com> wrote:
>>> On Thursday 05 February 2009 11:09:56 teawater wrote:
>>>> Hi Marc,
>>>>
>>>> I read the source code in infcmd.c:finish_backward.
>>>> This is because function "proceed" will be call twice in
>>>> "finish_backward". Maybe MI output depend some
>>>> observer_notify_target_xxx function. So it output twice.
>>>
>>> The *stopped notification is output as result of call to
>>>
>>>        observer_notify_normal_stop
>>>
>>> which is done in infrun.c:normal_stop. I do believe that "silent" breakpoint
>>> should generate *stopped, since otherwise frontend will assume the target is
>>> running. Furthermore, I believe that silent breakpoints, in MI, should behave
>>> identically to ordinary breakpoints -- as it stands, we print *stopped without
>>> frame information.
>>>
>>>
>>> I don't know why a silent breakpoint is used in implementation of reverse-finish,
>>> nor do I understand why normal_stop is called in the middle of reverse-finish when
>>> stopping on that temporary breakpoint. I think the first fix it to make reverse-finish
>>> not to call normal_stop on that internal breakpoint (just like normal_stop is not
>>> called on solib load breakpoint).
>>
>> The normal_stop is called twice in reverse-finish because
>> finish_backward call "proceed" twice, "proceed" call normal_stop.
>
> Then I presume you get to change that. I don't see any way we can overload
> 'silent' breakpoint to output something in most cases, except for reverse-finish.
> And if you are going to add some flag to indicate breakpoints used for single-step,
> you might as well change handle_inferiour_event to do extra reverse step when such
> breakpoint is hit.
>

I am not very clear about function "finish_backward". But maybe I can
try with it.

Michael, sorry for forget mail you about this issue, do you have some
idea with it?

Hui



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