From 4ead09a294adbb718d642874a554e78d931c2830 Mon Sep 17 00:00:00 2001
From: Tom Tromey <tromey@adacore.com>
Date: Tue, 24 Oct 2023 08:05:06 -0600
Subject: [PATCH] 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>
---
 gdb/NEWS              |  3 +++
 gdb/doc/python.texi   | 10 ++++++++++
 gdb/python/py-frame.c | 26 ++++++++++++++++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/gdb/NEWS b/gdb/NEWS
index 96aba256dbb..93fbcf1c13e 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -424,6 +424,9 @@ 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 c26949e0510..c3dfc7ae0fa 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -5739,6 +5739,16 @@ 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 1a55e514e39..0a7e10f09ff 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 */
 };
 
-- 
2.30.2