aboutsummaryrefslogtreecommitdiff
path: root/gdb/python/lib/gdb/unwinder.py
blob: bb0db79a19830625cdf432213237b15754e48e68 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
# Copyright (C) 2015-2024 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.
        """

        if not isinstance(name, str):
            raise TypeError("incorrect type for name: %s" % type(name))

        self._name = name
        self._enabled = True

    @property
    def name(self):
        return self._name

    @property
    def enabled(self):
        return self._enabled

    @enabled.setter
    def enabled(self, value):
        if not isinstance(value, bool):
            raise TypeError("incorrect type for enabled attribute: %s" % type(value))
        self._enabled = value
        gdb.invalidate_cached_frames()

    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__.")


class FrameId(object):
    """A Frame-ID class for use when creating gdb.UnwindInfo objects.

    Attributes (all read-only):
        pc: Program counter value.
        sp: The stack-pointer value.
        special: An alternative stack-pointer value, can be None."""

    def __init__(self, sp, pc, special=None):
        self._sp = sp
        self._pc = pc
        self._special = special

    @property
    def sp(self):
        return self._sp

    @property
    def pc(self):
        return self._pc

    @property
    def special(self):
        return self._special


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()