# Copyright (C) 2015-2020 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""Unwinder class and register_unwinder function."""
import gdb
class Unwinder(object):
"""Base class (or a template) for frame unwinders written in Python.
An unwinder has a single method __call__ and the attributes
described below.
Attributes:
name: The name of the unwinder.
enabled: A boolean indicating whether the unwinder is enabled.
"""
def __init__(self, name):
"""Constructor.
Args:
name: An identifying name for the unwinder.
"""
self.name = name
self.enabled = True
def __call__(self, pending_frame):
"""GDB calls this method to unwind a frame.
Arguments:
pending_frame: gdb.PendingFrame instance.
Returns:
gdb.UnwindInfo instance.
"""
raise NotImplementedError("Unwinder __call__.")
def register_unwinder(locus, unwinder, replace=False):
"""Register unwinder in given locus.
The unwinder is prepended to the locus's unwinders list. Unwinder
name should be unique.
Arguments:
locus: Either an objfile, progspace, or None (in which case
the unwinder is registered globally).
unwinder: An object of a gdb.Unwinder subclass
replace: If True, replaces existing unwinder with the same name.
Otherwise, raises exception if unwinder with the same
name already exists.
Returns:
Nothing.
Raises:
RuntimeError: Unwinder name is not unique
TypeError: Bad locus type
"""
if locus is None:
if gdb.parameter("verbose"):
gdb.write("Registering global %s unwinder ...\n" % unwinder.name)
locus = gdb
elif isinstance(locus, gdb.Objfile) or isinstance(locus, gdb.Progspace):
if gdb.parameter("verbose"):
gdb.write("Registering %s unwinder for %s ...\n" %
(unwinder.name, locus.filename))
else:
raise TypeError("locus should be gdb.Objfile or gdb.Progspace or None")
i = 0
for needle in locus.frame_unwinders:
if needle.name == unwinder.name:
if replace:
del locus.frame_unwinders[i]
else:
raise RuntimeError("Unwinder %s already exists." %
unwinder.name)
i += 1
locus.frame_unwinders.insert(0, unwinder)
gdb.invalidate_cached_frames()