Xmethod support in Python.

* python/py-xmethods.c: New file.
	* python/py-objfile.c (objfile_object): New field 'xmethods'.
	(objfpy_dealloc): XDECREF on the new xmethods field.
	(objfpy_new, objfile_to_objfile_object): Initialize xmethods
	field.
	(objfpy_get_xmethods): New function.
	(objfile_getset): New entry 'xmethods'.
	* python/py-progspace.c (pspace_object): New field 'xmethods'.
	(pspy_dealloc): XDECREF on the new xmethods field.
	(pspy_new, pspace_to_pspace_object): Initialize	xmethods
	field.
	(pspy_get_xmethods): New function.
	(pspace_getset): New entry 'xmethods'.
	* python/python-internal.h: Add declarations for new functions.
	* python/python.c (_initialize_python): Invoke
	gdbpy_initialize_xmethods.
	* python/lib/gdb/__init__.py (xmethods): New
	attribute.
	* python/lib/gdb/xmethod.py: New file.
	* python/lib/gdb/command/xmethods.py: New file.

	testuite/
	* gdb.python/py-xmethods.cc: New testcase to test xmethods.
	* gdb.python/py-xmethods.exp: New tests to test xmethods.
	* gdb.python/py-xmethods.py: Python script supporting the
	new testcase and tests.

gdb/python/py-progspace.c

@@ -39,6 +39,9 @@ typedef struct
   PyObject *frame_filters;
   /* The type-printer list.  */
   PyObject *type_printers;
+
+  /* The debug method list.  */
+  PyObject *xmethods;
 } pspace_object;
 
 static PyTypeObject pspace_object_type
@@ -75,6 +78,7 @@ pspy_dealloc (PyObject *self)
   Py_XDECREF (ps_self->printers);
   Py_XDECREF (ps_self->frame_filters);
   Py_XDECREF (ps_self->type_printers);
+  Py_XDECREF (ps_self->xmethods);
   Py_TYPE (self)->tp_free (self);
 }
 
@@ -107,6 +111,13 @@ pspy_new (PyTypeObject *type, PyObject *args, PyObject *keywords)
 	  Py_DECREF (self);
 	  return NULL;
 	}
+
+      self->xmethods = PyList_New (0);
+      if (self->xmethods == NULL)
+	{
+	  Py_DECREF (self);
+	  return NULL;
+	}
     }
   return (PyObject *) self;
 }
@@ -201,6 +212,17 @@ pspy_get_type_printers (PyObject *o, void *ignore)
   return self->type_printers;
 }
 
+/* Get the 'xmethods' attribute.  */
+
+PyObject *
+pspy_get_xmethods (PyObject *o, void *ignore)
+{
+  pspace_object *self = (pspace_object *) o;
+
+  Py_INCREF (self->xmethods);
+  return self->xmethods;
+}
+
 /* Set the 'type_printers' attribute.  */
 
 static int
@@ -297,6 +319,13 @@ pspace_to_pspace_object (struct program_space *pspace)
 	      return NULL;
 	    }
 
+	  object->xmethods = PyList_New (0);
+	  if (object->xmethods == NULL)
+	    {
+	      Py_DECREF (object);
+	      return NULL;
+	    }
+
 	  set_program_space_data (pspace, pspy_pspace_data_key, object);
 	}
     }
@@ -329,6 +358,8 @@ static PyGetSetDef pspace_getset[] =
     "Frame filters.", NULL },
   { "type_printers", pspy_get_type_printers, pspy_set_type_printers,
     "Type printers.", NULL },
+  { "xmethods", pspy_get_xmethods, NULL,
+    "Debug methods.", NULL },
   { NULL }
 };