Add gdb.free_objfile event registry

Currently, Python code can use event registries to detect when gdb
loads a new objfile, and when gdb clears the objfile list.  However,
there's no way to detect the removal of an objfile, say when the
inferior calls dlclose.

This patch adds a gdb.free_objfile event registry and arranges for an
event to be emitted in this case.

1 files changed, 42 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.python/py-event-load.c b/gdb/testsuite/gdb.python/py-event-load.c
new file mode 100644
index 0000000..de89c5e
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-event-load.c
@@ -0,0 +1,42 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2022 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see  <http://www.gnu.org/licenses/>.  */
+
+#include <unistd.h>
+
+#ifdef __WIN32__
+#include <windows.h>
+#define dlopen(name, mode) LoadLibrary (TEXT (name))
+#define dlclose(handle) FreeLibrary (handle)
+#else
+#include <dlfcn.h>
+#endif
+
+/* This is updated by the .exp file.  */
+char *libname = "py-events-shlib.so";
+
+int
+main ()
+{
+  void *h;
+
+  h = dlopen (libname, RTLD_LAZY);
+
+  dlclose (h);
+
+  h = NULL;			/* final breakpoint here */
+  return 0;
+}