summaryrefslogtreecommitdiff
path: root/gdb/frame-info.h
blob: 1d2d4bdc7e6898e51fdad53ef64283b285e482a8 (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
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
/* Frame info pointer

   Copyright (C) 2022 Free Software Foundation, Inc.

   This file is part of GDB.

   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/>.  */

#ifndef GDB_FRAME_INFO_H
#define GDB_FRAME_INFO_H

#include "gdbsupport/intrusive_list.h"
#include "frame-id.h"

struct frame_info;

/* A wrapper for "frame_info *".  frame_info objects are invalidated
   whenever reinit_frame_cache is called.  This class arranges to
   invalidate the pointer when appropriate.  This is done to help
   detect a GDB bug that was relatively common.

   A small amount of code must still operate on raw pointers, so a
   "get" method is provided.  However, you should normally not use
   this in new code.  */

class frame_info_ptr : public intrusive_list_node<frame_info_ptr>
{
public:
  /* Create a frame_info_ptr from a raw pointer.  */
  explicit frame_info_ptr (struct frame_info *ptr)
    : m_ptr (ptr)
  {
    frame_list.push_back (*this);
  }

  /* Create a null frame_info_ptr.  */
  frame_info_ptr ()
  {
    frame_list.push_back (*this);
  }

  frame_info_ptr (std::nullptr_t)
  {
    frame_list.push_back (*this);
  }

  frame_info_ptr (const frame_info_ptr &other)
    : m_ptr (other.m_ptr), m_cached_id (other.m_cached_id)
  {
    frame_list.push_back (*this);
  }

  frame_info_ptr (frame_info_ptr &&other)
    : m_ptr (other.m_ptr), m_cached_id (other.m_cached_id)
  {
    other.m_ptr = nullptr;
    other.m_cached_id = null_frame_id;
    frame_list.push_back (*this);
  }

  ~frame_info_ptr ()
  {
    frame_list.erase (frame_list.iterator_to (*this));
  }

  frame_info_ptr &operator= (const frame_info_ptr &other)
  {
    m_ptr = other.m_ptr;
    m_cached_id = other.m_cached_id;
    return *this;
  }

  frame_info_ptr &operator= (std::nullptr_t)
  {
    m_ptr = nullptr;
    m_cached_id = null_frame_id;
    return *this;
  }

  frame_info_ptr &operator= (frame_info_ptr &&other)
  {
    m_ptr = other.m_ptr;
    m_cached_id = other.m_cached_id;
    other.m_ptr = nullptr;
    other.m_cached_id = null_frame_id;
    return *this;
  }

  frame_info *operator-> () const
  {
    return m_ptr;
  }

  /* Fetch the underlying pointer.  Note that new code should
     generally not use this -- avoid it if at all possible.  */
  frame_info *get () const
  {
    return m_ptr;
  }

  /* This exists for compatibility with pre-existing code that checked
     a "frame_info *" using "!".  */
  bool operator! () const
  {
    return m_ptr == nullptr;
  }

  /* This exists for compatibility with pre-existing code that checked
     a "frame_info *" like "if (ptr)".  */
  explicit operator bool () const
  {
    return m_ptr != nullptr;
  }

  /* Invalidate this pointer.  */
  void invalidate ()
  {
    m_ptr = nullptr;
  }

  /* Cache the frame_id that the pointer will use to reinflate.  */
  void prepare_reinflate ();

  /* Use the cached frame_id to reinflate the pointer.  */
  void reinflate ();

private:

  /* The underlying pointer.  */
  frame_info *m_ptr = nullptr;

  /* The frame_id of the underlying pointer.  */
  frame_id m_cached_id = null_frame_id;

  /* All frame_info_ptr objects are kept on an intrusive list.
     This keeps their construction and destruction costs
     reasonably small.  */
  static intrusive_list<frame_info_ptr> frame_list;

  /* A friend so it can invalidate the pointers.  */
  friend void reinit_frame_cache ();
};

static inline bool
operator== (const frame_info *self, const frame_info_ptr &other)
{
  return self == other.get ();
}

static inline bool
operator== (const frame_info_ptr &self, const frame_info_ptr &other)
{
  return self.get () == other.get ();
}

static inline bool
operator== (const frame_info_ptr &self, const frame_info *other)
{
  return self.get () == other;
}

static inline bool
operator!= (const frame_info *self, const frame_info_ptr &other)
{
  return self != other.get ();
}

static inline bool
operator!= (const frame_info_ptr &self, const frame_info_ptr &other)
{
  return self.get () != other.get ();
}

static inline bool
operator!= (const frame_info_ptr &self, const frame_info *other)
{
  return self.get () != other;
}

#endif /* GDB_FRAME_INFO_H */