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Re: [PATCH 03/12] Iterate over 'struct varobj_item' instead of PyObject
- From: Yao Qi <yao at codesourcery dot com>
- To: Tom Tromey <tromey at redhat dot com>
- Cc: <gdb-patches at sourceware dot org>
- Date: Fri, 23 May 2014 09:30:58 +0800
- Subject: Re: [PATCH 03/12] Iterate over 'struct varobj_item' instead of PyObject
- Authentication-results: sourceware.org; auth=none
- References: <1392367471-13527-1-git-send-email-yao at codesourcery dot com> <1392367471-13527-4-git-send-email-yao at codesourcery dot com> <87oayrj9j6 dot fsf at fleche dot redhat dot com>
On 05/22/2014 02:01 AM, Tom Tromey wrote:
> Yao> - if (!gdb_python_initialized)
> Yao> - return 0;
>
> Where is this check done now? I couldn't find the location.
>
Good catch.
> IIRC this check was added in response to some bug report; I think it
> only arises if Python can't be properly initialized somehow.
>
> If it was dropped I think it may need to be reinstated somewhere.
It should be moved to 'next' method of python varobj iterator,
because update_dynamic_varobj_children is independent of python,
and all python related code should be moved to python varobj
iterator.
At the beginning of update_dynamic_varobj_children,
if (update_children || var->dynamic->child_iter == NULL)
{
varobj_iter_delete (var->dynamic->child_iter);
var->dynamic->child_iter = varobj_get_iterator (var,
var->root->lang_ops);
varobj_clear_saved_item (var->dynamic);
i = 0;
if (var->dynamic->child_iter == NULL)
return 0;
}
else
i = VEC_length (varobj_p, var->children);
if gdb_python_initialized is false, varobj_get_iterator returns
NULL and update_dynamic_varobj_children returns zero too. The
behaviour is unchanged.
--
Yao (éå)
In previous patch, "saved_item" is still a PyOjbect and iteration is
still performed over PyObject. This patch continues to decouple
iteration from python code, so it changes its type to "struct
varobj_item *", so that the iterator itself is independent of python.
V2:
- Call varobj_delete_iter in free_variable.
- Fix changelog entries.
- Use XNEW.
V3:
- Return NULL early in py_varobj_iter_next if gdb_python_initialized
is false.
gdb:
2014-05-22 Pedro Alves <pedro@codesourcery.com>
Yao Qi <yao@codesourcery.com>
* python/py-varobj.c (py_varobj_iter_next): Return NULL if
gdb_python_initialized is false. Move some code from varobj.c.
* varobj-iter.h (struct varobj_item): Moved from varobj.c.
* varobj.c: Move "varobj-iter.h" inclusion earlier.
(struct varobj_item): Moved to varobj-iter.h".
(varobj_clear_saved_item): New function.
(update_dynamic_varobj_children): Move python-related code to
py-varobj.c.
(free_variable): Call varobj_clear_saved_item and
varobj_iter_delete.
---
gdb/python/py-varobj.c | 20 ++++++++++++-
gdb/varobj-iter.h | 13 +++++++--
gdb/varobj.c | 76 +++++++++++++++++---------------------------------
3 files changed, 56 insertions(+), 53 deletions(-)
diff --git a/gdb/python/py-varobj.c b/gdb/python/py-varobj.c
index 50bea40..40b28f4 100644
--- a/gdb/python/py-varobj.c
+++ b/gdb/python/py-varobj.c
@@ -53,6 +53,12 @@ py_varobj_iter_next (struct varobj_iter *self)
struct py_varobj_iter *t = (struct py_varobj_iter *) self;
struct cleanup *back_to;
PyObject *item;
+ PyObject *py_v;
+ varobj_item *vitem;
+ const char *name = NULL;
+
+ if (!gdb_python_initialized)
+ return NULL;
back_to = varobj_ensure_python_env (self->var);
@@ -100,9 +106,21 @@ py_varobj_iter_next (struct varobj_iter *self)
}
}
+ if (!PyArg_ParseTuple (item, "sO", &name, &py_v))
+ {
+ gdbpy_print_stack ();
+ error (_("Invalid item from the child list"));
+ }
+
+ vitem = xmalloc (sizeof *vitem);
+ vitem->value = convert_value_from_python (py_v);
+ if (vitem->value == NULL)
+ gdbpy_print_stack ();
+ vitem->name = xstrdup (name);
+
self->next_raw_index++;
do_cleanups (back_to);
- return item;
+ return vitem;
}
/* The 'vtable' of pretty-printed python varobj iterators. */
diff --git a/gdb/varobj-iter.h b/gdb/varobj-iter.h
index 3a530bc..9eb672d 100644
--- a/gdb/varobj-iter.h
+++ b/gdb/varobj-iter.h
@@ -14,9 +14,18 @@
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
-struct varobj_iter_ops;
+/* A node or item of varobj, composed of the name and the value. */
+
+typedef struct varobj_item
+{
+ /* Name of this item. */
+ char *name;
-typedef PyObject varobj_item;
+ /* Value of this item. */
+ struct value *value;
+} varobj_item;
+
+struct varobj_iter_ops;
/* A dynamic varobj iterator "class". */
diff --git a/gdb/varobj.c b/gdb/varobj.c
index 02cce5a..7e8b364 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -33,6 +33,7 @@
#include "vec.h"
#include "gdbthread.h"
#include "inferior.h"
+#include "varobj-iter.h"
#if HAVE_PYTHON
#include "python/python.h"
@@ -41,8 +42,6 @@
typedef int PyObject;
#endif
-#include "varobj-iter.h"
-
/* Non-zero if we want to see trace of varobj level stuff. */
unsigned int varobjdebug = 0;
@@ -110,17 +109,6 @@ struct varobj_root
struct varobj_root *next;
};
-/* A node or item of varobj, composed of the name and the value. */
-
-struct varobj_item
-{
- /* Name of this item. */
- char *name;
-
- /* Value of this item. */
- struct value *value;
-};
-
/* Dynamic part of varobj. */
struct varobj_dynamic
@@ -788,6 +776,18 @@ varobj_get_iterator (struct varobj *var)
requested an iterator from a non-dynamic varobj"));
}
+/* Release and clear VAR's saved item, if any. */
+
+static void
+varobj_clear_saved_item (struct varobj_dynamic *var)
+{
+ if (var->saved_item != NULL)
+ {
+ value_free (var->saved_item->value);
+ xfree (var->saved_item);
+ var->saved_item = NULL;
+ }
+}
#endif
static int
@@ -802,14 +802,8 @@ update_dynamic_varobj_children (struct varobj *var,
int to)
{
#if HAVE_PYTHON
- struct cleanup *back_to;
int i;
- if (!gdb_python_initialized)
- return 0;
-
- back_to = varobj_ensure_python_env (var);
-
*cchanged = 0;
if (update_children || var->dynamic->child_iter == NULL)
@@ -817,16 +811,12 @@ update_dynamic_varobj_children (struct varobj *var,
varobj_iter_delete (var->dynamic->child_iter);
var->dynamic->child_iter = varobj_get_iterator (var);
- Py_XDECREF (var->dynamic->saved_item);
- var->dynamic->saved_item = NULL;
+ varobj_clear_saved_item (var->dynamic);
i = 0;
if (var->dynamic->child_iter == NULL)
- {
- do_cleanups (back_to);
- return 0;
- }
+ return 0;
}
else
i = VEC_length (varobj_p, var->children);
@@ -835,10 +825,10 @@ update_dynamic_varobj_children (struct varobj *var,
are more children. */
for (; to < 0 || i < to + 1; ++i)
{
- PyObject *item;
+ varobj_item *item;
/* See if there was a leftover from last time. */
- if (var->dynamic->saved_item)
+ if (var->dynamic->saved_item != NULL)
{
item = var->dynamic->saved_item;
var->dynamic->saved_item = NULL;
@@ -846,6 +836,10 @@ update_dynamic_varobj_children (struct varobj *var,
else
{
item = varobj_iter_next (var->dynamic->child_iter);
+ /* Release vitem->value so its lifetime is not bound to the
+ execution of a command. */
+ if (item != NULL && item->value != NULL)
+ release_value_or_incref (item->value);
}
if (item == NULL)
@@ -858,36 +852,19 @@ update_dynamic_varobj_children (struct varobj *var,
/* We don't want to push the extra child on any report list. */
if (to < 0 || i < to)
{
- PyObject *py_v;
- const char *name;
- struct varobj_item varobj_item;
- struct cleanup *inner;
int can_mention = from < 0 || i >= from;
- inner = make_cleanup_py_decref (item);
-
- if (!PyArg_ParseTuple (item, "sO", &name, &py_v))
- {
- gdbpy_print_stack ();
- error (_("Invalid item from the child list"));
- }
-
- varobj_item.value = convert_value_from_python (py_v);
- if (varobj_item.value == NULL)
- gdbpy_print_stack ();
- varobj_item.name = xstrdup (name);
-
install_dynamic_child (var, can_mention ? changed : NULL,
can_mention ? type_changed : NULL,
can_mention ? new : NULL,
can_mention ? unchanged : NULL,
can_mention ? cchanged : NULL, i,
- &varobj_item);
- do_cleanups (inner);
+ item);
+
+ xfree (item);
}
else
{
- Py_XDECREF (var->dynamic->saved_item);
var->dynamic->saved_item = item;
/* We want to truncate the child list just before this
@@ -913,7 +890,6 @@ update_dynamic_varobj_children (struct varobj *var,
var->num_children = VEC_length (varobj_p, var->children);
- do_cleanups (back_to);
return 1;
#else
gdb_assert_not_reached ("should never be called if Python is not enabled");
@@ -2191,12 +2167,12 @@ free_variable (struct varobj *var)
Py_XDECREF (var->dynamic->constructor);
Py_XDECREF (var->dynamic->pretty_printer);
- Py_XDECREF (var->dynamic->child_iter);
- Py_XDECREF (var->dynamic->saved_item);
do_cleanups (cleanup);
}
#endif
+ varobj_iter_delete (var->dynamic->child_iter);
+ varobj_clear_saved_item (var->dynamic);
value_free (var->value);
/* Free the expression if this is a root variable. */
--
1.9.0