RFA: add gdb.newest_frame method

[Tom Tromey <tromey at redhat dot com>]

I needed a "newest_frame" method to go along with "selected_frame".
This patch adds this method, documentation, and a test case.

This needs a doc review.

Built and regtested on x86-64 (compile farm).

Ok?

Tom

2011-01-06  Tom Tromey  <tromey@redhat.com>

	PR python/12367:
	* NEWS: Add item.
	* python/python.c (GdbMethods): Add "newest_frame" method.
	* python/python-internal.h (gdbpy_newest_frame): Declare.
	* python/py-frame.c (gdbpy_newest_frame): New function.

2011-01-06  Tom Tromey  <tromey@redhat.com>

	* gdb.texinfo (Frames In Python): Document gdb.newest_thread.

2011-01-06  Tom Tromey  <tromey@redhat.com>

	* gdb.python/py-frame.exp: Test gdb.newest_frame.

diff --git a/gdb/NEWS b/gdb/NEWS
index 7c2b494..1f02dfc 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -43,6 +43,9 @@
 
   ** gdb.parameter("directories") is now available.
 
+  ** New function gdb.newest_frame returns the newest frame in the
+     selected thread.
+
 * C++ Improvements:
 
   ** GDB now puts template parameters in scope when debugging in an
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index f6a3747..6a27e9d 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -22514,6 +22514,11 @@ The following frame-related functions are available in the @code{gdb} module:
 Return the selected frame object.  (@pxref{Selection,,Selecting a Frame}).
 @end defun
 
+@findex gdb.newest_frame
+@defun newest_frame
+Return the newest frame object for the selected thread.
+@end defun
+
 @defun frame_stop_reason_string reason
 Return a string explaining the reason why @value{GDBN} stopped unwinding
 frames, as expressed by the given @var{reason} code (an integer, see the
diff --git a/gdb/python/py-frame.c b/gdb/python/py-frame.c
index 3e11db1..a52c8c7 100644
--- a/gdb/python/py-frame.c
+++ b/gdb/python/py-frame.c
@@ -498,6 +498,26 @@ frapy_select (PyObject *self, PyObject *args)
   Py_RETURN_NONE;
 }
 
+/* Implementation of gdb.newest_frame () -> gdb.Frame.
+   Returns the newest frame object.  */
+
+PyObject *
+gdbpy_newest_frame (PyObject *self, PyObject *args)
+{
+  struct frame_info *frame;
+  PyObject *frame_obj = NULL;   /* Initialize to appease gcc warning.  */
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      frame = get_current_frame ();
+      frame_obj = frame_info_to_frame_object (frame);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  return frame_obj;
+}
+
 /* Implementation of gdb.selected_frame () -> gdb.Frame.
    Returns the selected frame object.  */
 
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index c9630c3..80d0763 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -110,6 +110,7 @@ PyObject *gdbpy_history (PyObject *self, PyObject *args);
 PyObject *gdbpy_breakpoints (PyObject *, PyObject *);
 PyObject *gdbpy_frame_stop_reason_string (PyObject *, PyObject *);
 PyObject *gdbpy_lookup_symbol (PyObject *self, PyObject *args, PyObject *kw);
+PyObject *gdbpy_newest_frame (PyObject *self, PyObject *args);
 PyObject *gdbpy_selected_frame (PyObject *self, PyObject *args);
 PyObject *gdbpy_block_for_pc (PyObject *self, PyObject *args);
 PyObject *gdbpy_lookup_type (PyObject *self, PyObject *args, PyObject *kw);
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 770744e..375042c 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -1121,6 +1121,9 @@ static PyMethodDef GdbMethods[] =
   { "objfiles", gdbpy_objfiles, METH_NOARGS,
     "Return a sequence of all loaded objfiles." },
 
+  { "newest_frame", gdbpy_newest_frame, METH_NOARGS,
+    "newest_frame () -> gdb.Frame.\n\
+Return the newest frame object." },
   { "selected_frame", gdbpy_selected_frame, METH_NOARGS,
     "selected_frame () -> gdb.Frame.\n\
 Return the selected frame object." },
diff --git a/gdb/testsuite/gdb.python/py-frame.exp b/gdb/testsuite/gdb.python/py-frame.exp
index 0956398..e3b5629 100644
--- a/gdb/testsuite/gdb.python/py-frame.exp
+++ b/gdb/testsuite/gdb.python/py-frame.exp
@@ -73,11 +73,18 @@ gdb_test "python print bf1.read_var(\"i\", sb).type" "int" "test int i"
 
 gdb_breakpoint "f2"
 gdb_continue_to_breakpoint "breakpoint at f2"
+gdb_py_test_silent_cmd "python bframe = gdb.selected_frame()" \
+    "get bottommost frame" 0
 gdb_test "up" ".*" ""
 
 gdb_py_test_silent_cmd "python f1 = gdb.selected_frame ()" "get second frame" 0
 gdb_py_test_silent_cmd "python f0 = f1.newer ()" "get first frame" 0
 
+gdb_test "python print f1 == gdb.newest_frame()" False \
+    "selected frame -vs- newest frame"
+gdb_test "python print bframe == gdb.newest_frame()" True \
+    "newest frame -vs- newest frame"
+
 gdb_test "python print 'result =', f0 == f1" " = False" "test equality comparison (false)"
 gdb_test "python print 'result =', f0 == f0" " = True" "test equality comparison (true)"
 gdb_test "python print 'result =', f0 != f1" " = True" "test inequality comparison (true)"