RFC: fix atexit.register

[Tom Tromey <tromey at redhat dot com>]

A user on irc reported that Python's atexit.register did not work
properly in gdb.

This patch fixes the problem by installing a final cleanup that calls
Py_Finalize.

Regression tested on x86-64 F16.
New test case included.

Tom

	* NEWS: Update.
	* python/python.c (finalize_python): New function.
	(_initialize_python): Make a final cleanup.

	* gdb.python/python.exp: Test atexit.register.
---
 gdb/NEWS                            |    2 ++
 gdb/python/python.c                 |   14 ++++++++++++++
 gdb/testsuite/gdb.python/python.exp |   18 ++++++++++++++++++
 3 files changed, 34 insertions(+), 0 deletions(-)

diff --git a/gdb/NEWS b/gdb/NEWS
index e625e25..9571bcf 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -10,6 +10,8 @@
 
   ** Vectors can be created with gdb.Type.vector.
 
+  ** Python's atexit.register now works in GDB.
+
 * New Python-based convenience functions:
 
   ** $_memeq(buf1, buf2, length)
diff --git a/gdb/python/python.c b/gdb/python/python.c
index cb60877..a75a421 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -1396,6 +1396,19 @@ user_show_python (char *args, int from_tty)
 
 /* Initialize the Python code.  */
 
+/* This is installed as a final cleanup and cleans up the
+   interpreter.  This lets Python's 'atexit' work.  */
+
+static void
+finalize_python (void *ignore)
+{
+  struct cleanup *cleanup = ensure_python_env (target_gdbarch,
+					       current_language);
+
+  Py_Finalize ();
+  do_cleanups (cleanup);
+}
+
 /* Provide a prototype to silence -Wmissing-prototypes.  */
 extern initialize_file_ftype _initialize_python;
 
@@ -1573,6 +1586,7 @@ gdb.type_printers = []\n\
   PyThreadState_Swap (NULL);
   PyEval_ReleaseLock ();
 
+  make_final_cleanup (finalize_python, NULL);
 #endif /* HAVE_PYTHON */
 }
 
diff --git a/gdb/testsuite/gdb.python/python.exp b/gdb/testsuite/gdb.python/python.exp
index 9683b1c..177f94e 100644
--- a/gdb/testsuite/gdb.python/python.exp
+++ b/gdb/testsuite/gdb.python/python.exp
@@ -141,6 +141,24 @@ gdb_test "python print a" ".*aliases -- Aliases of other commands.*" "verify hel
 gdb_py_test_silent_cmd "python nothread = gdb.selected_thread()" "Attempt to aquire thread with no inferior" 1
 gdb_test "python print nothread == None" "True" "Ensure that no threads are returned"
 
+gdb_py_test_multiple "register atexit function" \
+    "python" "" \
+    "import atexit" "" \
+    "def printit(arg):" "" \
+    "  print arg" "" \
+    "atexit.register(printit, 'good bye world')" "" \
+    "end" ""
+
+send_gdb "quit\n"
+gdb_expect {
+    -re "good bye world" {
+	pass "atexit handling"
+    }
+    default {
+	fail "atexit handling"
+    }
+}
+
 # Start with a fresh gdb.
 clean_restart ${testfile}
 
-- 
1.7.7.6