Add gdb.Frame.static_link method

This adds a new gdb.Frame.static_link method to the gdb Python layer.
This can be used to find the static link frame for a given frame.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
(cherry picked from commit 4ead09a294adbb718d642874a554e78d931c2830)

3 files changed, 39 insertions, 0 deletions

diff --git a/gdb/NEWS b/gdb/NEWS
index 240f2d1..e0271ef 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -350,6 +350,9 @@ show tui mouse-events
 
   ** gdb.LazyString now implements the __str__ method.
 
+  ** New method gdb.Frame.static_link that returns the outer frame
+     of a nested function frame.
+
 *** Changes in GDB 13
 
 * MI version 1 is deprecated, and will be removed in GDB 14.
diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index a97e445..a1ed642 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -5671,6 +5671,16 @@ Set this frame to be the selected frame.  @xref{Stack, ,Examining the
 Stack}.
 @end defun
 
+@defun Frame.static_link ()
+In some languages (e.g., Ada, but also a GNU C extension), a nested
+function can access the variables in the outer scope.  This is done
+via a ``static link'', which is a reference from the nested frame to
+the appropriate outer frame.
+
+This method returns this frame's static link frame, if one exists.  If
+there is no static link, this method returns @code{None}.
+@end defun
+
 @defun Frame.level ()
 Return an integer, the stack frame level for this frame.  @xref{Frames, ,Stack Frames}.
 @end defun
diff --git a/gdb/python/py-frame.c b/gdb/python/py-frame.c
index 1a55e51..0a7e10f 100644
--- a/gdb/python/py-frame.c
+++ b/gdb/python/py-frame.c
@@ -622,6 +622,30 @@ frapy_language (PyObject *self, PyObject *args)
   Py_RETURN_NONE;
 }
 
+/* The static link for this frame.  */
+
+static PyObject *
+frapy_static_link (PyObject *self, PyObject *args)
+{
+  frame_info_ptr link;
+
+  try
+    {
+      FRAPY_REQUIRE_VALID (self, link);
+
+      link = frame_follow_static_link (link);
+    }
+  catch (const gdb_exception &except)
+    {
+      GDB_PY_HANDLE_EXCEPTION (except);
+    }
+
+  if (link == nullptr)
+    Py_RETURN_NONE;
+
+  return frame_info_to_frame_object (link);
+}
+
 /* Implementation of gdb.newest_frame () -> gdb.Frame.
    Returns the newest frame object.  */
 
@@ -800,6 +824,8 @@ Return the value of the variable in this frame." },
     "The stack level of this frame." },
   { "language", frapy_language, METH_NOARGS,
     "The language of this frame." },
+  { "static_link", frapy_static_link, METH_NOARGS,
+    "The static link of this frame, or None." },
   {NULL}  /* Sentinel */
 };