GDB (xrefs)
unwinder.py
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1 # Copyright (C) 2015 Free Software Foundation, Inc.
2 
3 # This program is free software; you can redistribute it and/or modify
4 # it under the terms of the GNU General Public License as published by
5 # the Free Software Foundation; either version 3 of the License, or
6 # (at your option) any later version.
7 #
8 # This program is distributed in the hope that it will be useful,
9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 # GNU General Public License for more details.
12 #
13 # You should have received a copy of the GNU General Public License
14 # along with this program. If not, see <http://www.gnu.org/licenses/>.
15 
16 """Unwinder class and register_unwinder function."""
17 
18 import gdb
19 
20 
21 class Unwinder(object):
22  """Base class (or a template) for frame unwinders written in Python.
23 
24  An unwinder has a single method __call__ and the attributes
25  described below.
26 
27  Attributes:
28  name: The name of the unwinder.
29  enabled: A boolean indicating whether the unwinder is enabled.
30  """
31 
32  def __init__(self, name):
33  """Constructor.
34 
35  Args:
36  name: An identifying name for the unwinder.
37  """
38  self.name = name
39  self.enabled = True
40 
41  def __call__(self, pending_frame):
42  """GDB calls this method to unwind a frame.
43 
44  Arguments:
45  pending_frame: gdb.PendingFrame instance.
46 
47  Returns:
48  gdb.UnwindInfo instance.
49  """
50  raise NotImplementedError("Unwinder __call__.")
51 
52 
53 def register_unwinder(locus, unwinder, replace=False):
54  """Register unwinder in given locus.
55 
56  The unwinder is prepended to the locus's unwinders list. Unwinder
57  name should be unique.
58 
59  Arguments:
60  locus: Either an objfile, progspace, or None (in which case
61  the unwinder is registered globally).
62  unwinder: An object of a gdb.Unwinder subclass
63  replace: If True, replaces existing unwinder with the same name.
64  Otherwise, raises exception if unwinder with the same
65  name already exists.
66 
67  Returns:
68  Nothing.
69 
70  Raises:
71  RuntimeError: Unwinder name is not unique
72  TypeError: Bad locus type
73  """
74  if locus is None:
75  if gdb.parameter("verbose"):
76  gdb.write("Registering global %s unwinder ...\n" % unwinder.name)
77  locus = gdb
78  elif isinstance(locus, gdb.Objfile) or isinstance(locus, gdb.Progspace):
79  if gdb.parameter("verbose"):
80  gdb.write("Registering %s unwinder for %s ...\n" %
81  (unwinder.name, locus.filename))
82  else:
83  raise TypeError("locus should be gdb.Objfile or gdb.Progspace or None")
84 
85  i = 0
86  for needle in locus.frame_unwinders:
87  if needle.name == unwinder.name:
88  if replace:
89  del locus.frame_unwinders[i]
90  else:
91  raise RuntimeError("Unwinder %s already exists." %
92  unwinder.name)
93  i += 1
94  locus.frame_unwinders.insert(0, unwinder)
def __call__(self, pending_frame)
Definition: unwinder.py:41
def register_unwinder
Definition: unwinder.py:53
def __init__(self, name)
Definition: unwinder.py:32