Remove more uses of explicit reference counting in Python

This changes some more place in the Python code to use gdbpy_ref
rather than explicit reference counting.  While doing this I found a
latent bug in typy_fields_items -- it was not checking for errors in
one spot.  I also changed valpy_dealloc to use Py_XDECREF rather than
an explicit "if".

gdb/ChangeLog
2019-01-03  Tom Tromey  <tom@tromey.com>

	* python/py-value.c (valpy_dealloc): Use Py_XDECREF.
	* python/py-type.c (typy_fields_items): Use gdbpy_ref.
	* python/py-progspace.c (pspy_set_printers): Use gdbpy_ref.
	(pspy_set_frame_filters, pspy_set_frame_unwinders)
	(pspy_set_type_printers): Likewise.
	* python/py-function.c (fnpy_init): Use gdbpy_ref.
	* python/py-cmd.c (cmdpy_init): Use gdbpy_ref.
	* python/py-objfile.c (objfpy_set_printers): Use gdbpy_ref.
	(objfpy_set_frame_filters, objfpy_set_frame_unwinders)
	(objfpy_set_type_printers): Likewise.

1 files changed, 4 insertions, 12 deletions

diff --git a/gdb/python/py-objfile.c b/gdb/python/py-objfile.c
index c5212b5..5f61b73 100644
--- a/gdb/python/py-objfile.c
+++ b/gdb/python/py-objfile.c
@@ -240,7 +240,6 @@ objfpy_get_printers (PyObject *o, void *ignore)
 static int
 objfpy_set_printers (PyObject *o, PyObject *value, void *ignore)
 {
-  PyObject *tmp;
   objfile_object *self = (objfile_object *) o;
 
   if (! value)
@@ -258,10 +257,9 @@ objfpy_set_printers (PyObject *o, PyObject *value, void *ignore)
     }
 
   /* Take care in case the LHS and RHS are related somehow.  */
-  tmp = self->printers;
+  gdbpy_ref<> tmp (self->printers);
   Py_INCREF (value);
   self->printers = value;
-  Py_XDECREF (tmp);
 
   return 0;
 }
@@ -281,7 +279,6 @@ objfpy_get_frame_filters (PyObject *o, void *ignore)
 static int
 objfpy_set_frame_filters (PyObject *o, PyObject *filters, void *ignore)
 {
-  PyObject *tmp;
   objfile_object *self = (objfile_object *) o;
 
   if (! filters)
@@ -299,10 +296,9 @@ objfpy_set_frame_filters (PyObject *o, PyObject *filters, void *ignore)
     }
 
   /* Take care in case the LHS and RHS are related somehow.  */
-  tmp = self->frame_filters;
+  gdbpy_ref<> tmp (self->frame_filters);
   Py_INCREF (filters);
   self->frame_filters = filters;
-  Py_XDECREF (tmp);
 
   return 0;
 }
@@ -323,7 +319,6 @@ objfpy_get_frame_unwinders (PyObject *o, void *ignore)
 static int
 objfpy_set_frame_unwinders (PyObject *o, PyObject *unwinders, void *ignore)
 {
-  PyObject *tmp;
   objfile_object *self = (objfile_object *) o;
 
   if (!unwinders)
@@ -341,10 +336,9 @@ objfpy_set_frame_unwinders (PyObject *o, PyObject *unwinders, void *ignore)
     }
 
   /* Take care in case the LHS and RHS are related somehow.  */
-  tmp = self->frame_unwinders;
+  gdbpy_ref<> tmp (self->frame_unwinders);
   Py_INCREF (unwinders);
   self->frame_unwinders = unwinders;
-  Py_XDECREF (tmp);
 
   return 0;
 }
@@ -376,7 +370,6 @@ objfpy_get_xmethods (PyObject *o, void *ignore)
 static int
 objfpy_set_type_printers (PyObject *o, PyObject *value, void *ignore)
 {
-  PyObject *tmp;
   objfile_object *self = (objfile_object *) o;
 
   if (! value)
@@ -394,10 +387,9 @@ objfpy_set_type_printers (PyObject *o, PyObject *value, void *ignore)
     }
 
   /* Take care in case the LHS and RHS are related somehow.  */
-  tmp = self->type_printers;
+  gdbpy_ref<> tmp (self->type_printers);
   Py_INCREF (value);
   self->type_printers = value;
-  Py_XDECREF (tmp);
 
   return 0;
 }