Re: [PATCH] Fix mi-detach.exp on native-gdbserver

[Simon Marchi <simon dot marchi at ericsson dot com>]

On 15-09-09 05:39 AM, Pedro Alves wrote:
> Please try enabling "set print inferior-events on".  With native
> debugging, we currently get:
> 
>  (gdb) detach
>  Detaching from program: /home/pedro/gdb/tests/main, process 15759
>  [Inferior 15759 detached]
>                  ^^^^^^^^
> 
> However, with target extended-remote, we get:
> 
>  (gdb) tar extended-remote :9999
>  (gdb) detach
>  Detaching from program: /home/pedro/gdb/tests/main, process 15789
>  [Inferior 15789 exited]
>                  ^^^^^^
> 
> And with target remote, we get nothing:
> 
>  (gdb) tar remote :9999
>  0x0000003615a011f0 in _start () from target:/lib64/ld-linux-x86-64.so.2
>  (gdb) detach
>  Detaching from program: /home/pedro/gdb/tests/main, process 15767
>  Ending remote debugging.
>  (gdb)
> 
> With your patch, we'll print "exited" in the remote case too,
> when it seems to me that in both extended-remote and remote
> we should be saying "detached" like in the native case.
> 
> Also, if the user does "disconnect", after your patch gdb will
> say the inferiors we were debugging "exited" while they were
> left running on the target side.  Is that confusing?
> 
> Thanks,
> Pedro Alves

The fact that different targets have different behaviors is certainly confusing
and I think it should be improved.

The problem seems to be that remote_mourn and extended_remote_mourn don't have
enough information as to why they are mourning an inferior, so they just end up
calling exit_inferior.  In the native case, the message is right because
inf_ptrace_detach calls directly detach_inferior (which is exactly like
exit_inferior, except the message).  By the way, it means that when detaching
natively, we never mourn the inferior, is it normal?.

According to these backtraces, it seems like it would be possible for the "mourn"
functions to take a "why are we mourning" argument, so that the message printed there
can be adjusted.

#0  remote_mourn (target=0x2136200 <remote_ops>) at /home/emaisin/src/binutils-gdb/gdb/remote.c:8502
#1  0x00000000007fb350 in delegate_mourn_inferior (self=0x2136200 <remote_ops>) at /home/emaisin/src/binutils-gdb/gdb/target-delegates.c:1285
#2  0x0000000000808b3e in target_mourn_inferior () at /home/emaisin/src/binutils-gdb/gdb/target.c:2317
#3  0x000000000064b2f2 in remote_detach_1 (args=0x0, from_tty=1) at /home/emaisin/src/binutils-gdb/gdb/remote.c:4723
#4  0x000000000064b353 in remote_detach (ops=0x2136200 <remote_ops>, args=0x0, from_tty=1) at /home/emaisin/src/binutils-gdb/gdb/remote.c:4734
#5  0x00000000007f747d in delegate_detach (self=0x2136200 <remote_ops>, arg1=0x0, arg2=1) at /home/emaisin/src/binutils-gdb/gdb/target-delegates.c:34
#6  0x0000000000808888 in target_detach (args=0x0, from_tty=1) at /home/emaisin/src/binutils-gdb/gdb/target.c:2216
#7  0x00000000007a4677 in detach_command (args=0x0, from_tty=1) at /home/emaisin/src/binutils-gdb/gdb/infcmd.c:2908

#0  extended_remote_mourn (target=0x2136780 <extended_remote_ops>) at /home/emaisin/src/binutils-gdb/gdb/remote.c:8511
#1  0x00000000007fb2a8 in delegate_mourn_inferior (self=0x2136780 <extended_remote_ops>) at /home/emaisin/src/binutils-gdb/gdb/target-delegates.c:1285
#2  0x0000000000808a7f in target_mourn_inferior () at /home/emaisin/src/binutils-gdb/gdb/target.c:2317
#3  0x000000000064b27b in remote_detach_1 (args=0x0, from_tty=1) at /home/emaisin/src/binutils-gdb/gdb/remote.c:4723
#4  0x000000000064b302 in extended_remote_detach (ops=0x2136780 <extended_remote_ops>, args=0x0, from_tty=1) at /home/emaisin/src/binutils-gdb/gdb/remote.c:4740
#5  0x00000000007f73dd in delegate_detach (self=0x2136780 <extended_remote_ops>, arg1=0x0, arg2=1) at /home/emaisin/src/binutils-gdb/gdb/target-delegates.c:34
#6  0x00000000008087d8 in target_detach (args=0x0, from_tty=1) at /home/emaisin/src/binutils-gdb/gdb/target.c:2216
#7  0x00000000007a45e1 in detach_command (args=0x0, from_tty=1) at /home/emaisin/src/binutils-gdb/gdb/infcmd.c:2908

Does it make sense?