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Re: [RFC] New gdbserver Win32 interrupt code
Welcome back!
Thanks!
I also implemented the synthetic suspending here, because soon
after that thread, I had a need for it in WinCE. Unfortunatelly, I got
distracted with other things and never submitted. I hate it when
work gets duplicated :(
Yep, me too. :(
There's one benefit though, which is that things that slip through one's
mind, may not through the other's. Merging may give us the super-patch! ;)
At a quick glance, I think your patch should be at least split
in 3.
You mean three different patches? Submitted individually?
I didn't submit thread pause counting separately, as it was a really
simple fix (one line).
I'll write that down for next time.
1 - the synthetic suspending
On WinCE, the synthetic suspending is also needed when
attaching, since in opposition to 9xNT, the OS doesn't stop
the inferior at all (neither when attaching nor running).
If you're OK with it, I'll clean up my patch a bit, and merge
with your bits so 1 can go in first. It will be easier for me
this way, since I've already taken care of the function
reusing and ifdefing minimising. I'll then volunteer to
clean up the rest of your patch for you, as a reward for
you patience ;)
Sure, no problem with that.
When you do so, please note that in the patch main pausing function
synthetic_child_interrupt, which just pauses or resumes the child
process, every single line is important (at least for Win32) and is
there for a reason, as is also the order of calls, according to the
conversation in the old thread.
I'd like to know what you are referring to when you say clean up the
rest of my patch. I took care of properly formatting code, full stops,
and even fixed some previous erroneous code indentation and formatting.
I'd like to know, what is it I missed that you are talking about?
I'd also like to know what ifdefing in the patch I submitted that you
don't like. The NEW_INT macro is the only one I sent, and I left it
there just in case this new interrupt code isn't suitable for all, but
can be removed easily.
Also, note that I did not include this synthetic_child_interrupt into
separate architecture files (i386/arm) because of one of the benefits of
this pausing method, which is portability among Windows versions, and
this new code is compatible from Win95 and newer, however I don't know
about WinCE.
2 - the suspend count handling
This is also a problem in native debugging
(gdb/win32-nat.c). I also saw this when doing my version
Yes, actually when I wrote win32 gdbserver port, I started from
modifying gdb/win32-nat.c, and the thread_rec function if I remember
right is the same one, apart from the arch (i386/arm) modifications you
made, so truly the problem must be there in native gdb too.
By the way, maybe this interrupt method could be of interest for native
Win32 gdb.
If so, should we handle the native win32 patch, or should that be done
by their respective maintainers?
Also note, that this problem is not a problem I have seen to fail in
practice, so maybe it isn't a problem at all (for some reason). This fix
is just something I noticed when I wrote the new interrupt function,
which ultimately relies on thread_rec function.
of 1. I got a chance to look at the logs of the native
WinCE debugger, and could infer that it also takes care of
this correctly. The way they do it, is to read the current
suspend count by always doing a SuspendThread + ResumeThread
sequence on a debug event (ResumeThread return the current
suspend count).
But isn't this wrong too, according to my explanation in my previous
message?
The problem actually is that when resuming a thread in win32-nat.c, in
function continue_one_thread, which resumes a thread suspend_count
times, which itself was being set to the number of suspends of the
thread as reported by Windows, so for example if the client app had a
thread, say suspended 2 times, and then gdbserver suspends the thread
again, the internal gdbserver count would be 3, and when resuming it,
gdbserver would wake it up three times, which is wrong because the child
wanted it to be suspended 2 times.
3 - the elevation
What do you mean by this?
Regards,
Leo.