gdb: centralize "[Thread ...exited]" notifications

Currently, each target backend is responsible for printing "[Thread
...exited]" before deleting a thread.  This leads to unnecessary
differences between targets, like e.g. with the remote target, we
never print such messages, even though we do print "[New Thread ...]".

E.g., debugging the gdb.threads/attach-many-short-lived-threads.exp
with gdbserver, letting it run for a bit, and then pressing Ctrl-C, we
currently see:

 (gdb) c
 Continuing.
 ^C[New Thread 3850398.3887449]
 [New Thread 3850398.3887500]
 [New Thread 3850398.3887551]
 [New Thread 3850398.3887602]
 [New Thread 3850398.3887653]
 ...

 Thread 1 "attach-many-sho" received signal SIGINT, Interrupt.
 0x00007ffff7e6a23f in __GI___clock_nanosleep (clock_id=clock_id@entry=0, flags=flags@entry=0, req=req@entry=0x7fffffffda80, rem=rem@entry=0x7fffffffda80)
     at ../sysdeps/unix/sysv/linux/clock_nanosleep.c:78
 78      in ../sysdeps/unix/sysv/linux/clock_nanosleep.c
 (gdb)

Above, we only see "New Thread" notifications, even though threads
were deleted.

After this patch, we'll see:

 (gdb) c
 Continuing.
 ^C[Thread 3558643.3577053 exited]
 [Thread 3558643.3577104 exited]
 [Thread 3558643.3577155 exited]
 [Thread 3558643.3579603 exited]
 ...
 [New Thread 3558643.3597415]
 [New Thread 3558643.3600015]
 [New Thread 3558643.3599965]
 ...

 Thread 1 "attach-many-sho" received signal SIGINT, Interrupt.
 0x00007ffff7e6a23f in __GI___clock_nanosleep (clock_id=clock_id@entry=0, flags=flags@entry=0, req=req@entry=0x7fffffffda80, rem=rem@entry=0x7fffffffda80)
     at ../sysdeps/unix/sysv/linux/clock_nanosleep.c:78
 78      in ../sysdeps/unix/sysv/linux/clock_nanosleep.c
 (gdb) q

This commit fixes this by moving the thread exit printing to common
code instead, triggered from within delete_thread (or rather,
set_thread_exited).

There's one wrinkle, though.  While most targest want to print:

 [Thread ... exited]

the Windows target wants to print:

 [Thread ... exited with code <exit_code>]

... and sometimes wants to suppress the notification for the main
thread.  To address that, this commits adds a delete_thread_with_code
function, only used by that target (so far).

This fix was originally posted as part of a larger series:

  https://inbox.sourceware.org/gdb-patches/20221212203101.1034916-1-pedro@palves.net/

But didn't really need to be part of that series.  In order to get
this fix merged sooner, I (Andrew Burgess) have rebased this commit
outside of the original series.  Any bugs introduced while splitting
this patch out and rebasing, are entirely my own.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30129
Co-Authored-By: Andrew Burgess <aburgess@redhat.com>

1 files changed, 18 insertions, 4 deletions

diff --git a/gdb/gdbthread.h b/gdb/gdbthread.h
index baff68a..48f32bb 100644
--- a/gdb/gdbthread.h
+++ b/gdb/gdbthread.h
@@ -623,16 +623,30 @@ extern struct thread_info *add_thread_with_info (process_stratum_target *targ,
 
 /* Delete thread THREAD and notify of thread exit.  If the thread is
    currently not deletable, don't actually delete it but still tag it
-   as exited and do the notification.  */
-extern void delete_thread (struct thread_info *thread);
+   as exited and do the notification.  EXIT_CODE is the thread's exit
+   code.  If SILENT, don't actually notify the CLI.  THREAD must not
+   be NULL or an assertion will fail.  */
+extern void delete_thread_with_exit_code (thread_info *thread,
+					  ULONGEST exit_code,
+					  bool silent = false);
+
+/* Delete thread THREAD and notify of thread exit.  If the thread is
+   currently not deletable, don't actually delete it but still tag it
+   as exited and do the notification.  THREAD must not be NULL or an
+   assertion will fail.  */
+extern void delete_thread (thread_info *thread);
 
 /* Like delete_thread, but be quiet about it.  Used when the process
    this thread belonged to has already exited, for example.  */
 extern void delete_thread_silent (struct thread_info *thread);
 
 /* Mark the thread exited, but don't delete it or remove it from the
-   inferior thread list.  */
-extern void set_thread_exited (thread_info *tp, bool silent);
+   inferior thread list.  EXIT_CODE is the thread's exit code, if
+   available.  If SILENT, then don't inform the CLI about the
+   exit.  */
+extern void set_thread_exited (thread_info *tp,
+			       gdb::optional<ULONGEST> exit_code = {},
+			       bool silent = false);
 
 /* Delete a step_resume_breakpoint from the thread database.  */
 extern void delete_step_resume_breakpoint (struct thread_info *);