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>

2 files changed, 4 insertions, 22 deletions

diff --git a/gdb/testsuite/gdb.mi/mi-thread-bp-deleted.exp b/gdb/testsuite/gdb.mi/mi-thread-bp-deleted.exp
index 0ebca92..bffbb29 100644
--- a/gdb/testsuite/gdb.mi/mi-thread-bp-deleted.exp
+++ b/gdb/testsuite/gdb.mi/mi-thread-bp-deleted.exp
@@ -235,17 +235,9 @@ foreach_mi_ui_mode mode {
 
 	    # The output has arrived!  Check how we did.  There are other bugs
 	    # that come into play here which change what output we'll see.
-	    if { $saw_mi_thread_exited && $saw_mi_bp_deleted \
-		     && $saw_cli_thread_exited \
-		     && $saw_cli_bp_deleted } {
-		kpass "gdb/30129" $gdb_test_name
-	    } elseif { $saw_mi_thread_exited && $saw_mi_bp_deleted \
-			   && !$saw_cli_thread_exited \
-			   && $saw_cli_bp_deleted } {
-		kfail "gdb/30129" $gdb_test_name
-	    } else {
-		fail "$gdb_test_name"
-	    }
+	    gdb_assert { $saw_mi_thread_exited && $saw_mi_bp_deleted \
+			     && $saw_cli_thread_exited \
+			     && $saw_cli_bp_deleted } $gdb_test_name
 	}
     }
 
diff --git a/gdb/testsuite/gdb.threads/thread-bp-deleted.exp b/gdb/testsuite/gdb.threads/thread-bp-deleted.exp
index 019bddde..92178ff 100644
--- a/gdb/testsuite/gdb.threads/thread-bp-deleted.exp
+++ b/gdb/testsuite/gdb.threads/thread-bp-deleted.exp
@@ -155,17 +155,7 @@ if {$is_remote} {
 		exp_continue
 	    }
 
-	    # When PR gdb/30129 is fixed then this can all be collapsed down
-	    # into a single gdb_assert call.  This is split out like this
-	    # because the SAW_BP_DELETED part is working, and we want to
-	    # spot if that stops working.
-	    if { $saw_thread_exited && $saw_bp_deleted } {
-		kpass "gdb/30129" $gdb_test_name
-	    } elseif {!$saw_thread_exited && $saw_bp_deleted} {
-		kfail "gdb/30129" $gdb_test_name
-	    } else {
-		fail $gdb_test_name
-	    }
+	    gdb_assert { $saw_thread_exited && $saw_bp_deleted } $gdb_test_name
 	}
     }
 } else {