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poison.h
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1 /* Poison symbols at compile time.
2
3 Copyright (C) 2017-2018 Free Software Foundation, Inc.
4
5 This file is part of GDB.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19
20 #ifndef COMMON_POISON_H
21 #define COMMON_POISON_H
22
23 #include "traits.h"
24
25 /* Poison memset of non-POD types. The idea is catching invalid
26 initialization of non-POD structs that is easy to be introduced as
27 side effect of refactoring. For example, say this:
28
29 struct S { VEC(foo_s) *m_data; };
30
31 is converted to this at some point:
32
33 struct S {
34 S() { m_data.reserve (10); }
35 std::vector<foo> m_data;
36 };
37
38 and old code was initializing S objects like this:
39
40 struct S s;
41 memset (&s, 0, sizeof (S)); // whoops, now wipes vector.
42
43 Declaring memset as deleted for non-POD types makes the memset above
44 be a compile-time error. */
45
46 /* Helper for SFINAE. True if "T *" is memsettable. I.e., if T is
47 either void, or POD. */
48 template<typename T>
49 struct IsMemsettable
50 : gdb::Or<std::is_void<T>,
51 std::is_pod<T>>
52 {};
53
54 template <typename T,
55 typename = gdb::Requires<gdb::Not<IsMemsettable<T>>>>
56 void *memset (T *s, int c, size_t n) = delete;
57
58 #if HAVE_IS_TRIVIALLY_COPYABLE
59
60 /* Similarly, poison memcpy and memmove of non trivially-copyable
61 types, which is undefined. */
62
63 /* True if "T *" is relocatable. I.e., copyable with memcpy/memmove.
64 I.e., T is either trivially copyable, or void. */
65 template<typename T>
66 struct IsRelocatable
67 : gdb::Or<std::is_void<T>,
68 std::is_trivially_copyable<T>>
69 {};
70
71 /* True if both source and destination are relocatable. */
72
73 template <typename D, typename S>
74 using BothAreRelocatable
75 = gdb::And<IsRelocatable<D>, IsRelocatable<S>>;
76
77 template <typename D, typename S,
78 typename = gdb::Requires<gdb::Not<BothAreRelocatable<D, S>>>>
79 void *memcpy (D *dest, const S *src, size_t n) = delete;
80
81 template <typename D, typename S,
82 typename = gdb::Requires<gdb::Not<BothAreRelocatable<D, S>>>>
83 void *memmove (D *dest, const S *src, size_t n) = delete;
84
85 #endif /* HAVE_IS_TRIVIALLY_COPYABLE */
86
87 /* Poison XNEW and friends to catch usages of malloc-style allocations on
88 objects that require new/delete. */
89
90 template<typename T>
91 using IsMallocable = std::is_pod<T>;
92
93 template<typename T>
94 using IsFreeable = gdb::Or<std::is_trivially_destructible<T>, std::is_void<T>>;
95
96 template <typename T, typename = gdb::Requires<gdb::Not<IsFreeable<T>>>>
97 void free (T *ptr) = delete;
98
99 template<typename T>
100 static T *
101 xnew ()
102 {
103 static_assert (IsMallocable<T>::value, "Trying to use XNEW with a non-POD \
104 data type. Use operator new instead.");
105 return XNEW (T);
106 }
107
108 #undef XNEW
109 #define XNEW(T) xnew<T>()
110
111 template<typename T>
112 static T *
113 xcnew ()
114 {
115 static_assert (IsMallocable<T>::value, "Trying to use XCNEW with a non-POD \
116 data type. Use operator new instead.");
117 return XCNEW (T);
118 }
119
120 #undef XCNEW
121 #define XCNEW(T) xcnew<T>()
122
123 template<typename T>
124 static void
125 xdelete (T *p)
126 {
127 static_assert (IsFreeable<T>::value, "Trying to use XDELETE with a non-POD \
128 data type. Use operator delete instead.");
129 XDELETE (p);
130 }
131
132 #undef XDELETE
133 #define XDELETE(P) xdelete (P)
134
135 template<typename T>
136 static T *
137 xnewvec (size_t n)
138 {
139 static_assert (IsMallocable<T>::value, "Trying to use XNEWVEC with a \
140 non-POD data type. Use operator new[] (or std::vector) instead.");
141 return XNEWVEC (T, n);
142 }
143
144 #undef XNEWVEC
145 #define XNEWVEC(T, N) xnewvec<T> (N)
146
147 template<typename T>
148 static T *
149 xcnewvec (size_t n)
150 {
151 static_assert (IsMallocable<T>::value, "Trying to use XCNEWVEC with a \
152 non-POD data type. Use operator new[] (or std::vector) instead.");
153 return XCNEWVEC (T, n);
154 }
155
156 #undef XCNEWVEC
157 #define XCNEWVEC(T, N) xcnewvec<T> (N)
158
159 template<typename T>
160 static T *
161 xresizevec (T *p, size_t n)
162 {
163 static_assert (IsMallocable<T>::value, "Trying to use XRESIZEVEC with a \
164 non-POD data type.");
165 return XRESIZEVEC (T, p, n);
166 }
167
168 #undef XRESIZEVEC
169 #define XRESIZEVEC(T, P, N) xresizevec<T> (P, N)
170
171 template<typename T>
172 static void
173 xdeletevec (T *p)
174 {
175 static_assert (IsFreeable<T>::value, "Trying to use XDELETEVEC with a \
176 non-POD data type. Use operator delete[] (or std::vector) instead.");
177 XDELETEVEC (p);
178 }
179
180 #undef XDELETEVEC
181 #define XDELETEVEC(P) xdeletevec (P)
182
183 template<typename T>
184 static T *
185 xnewvar (size_t s)
186 {
187 static_assert (IsMallocable<T>::value, "Trying to use XNEWVAR with a \
188 non-POD data type.");
189 return XNEWVAR (T, s);;
190 }
191
192 #undef XNEWVAR
193 #define XNEWVAR(T, S) xnewvar<T> (S)
194
195 template<typename T>
196 static T *
197 xcnewvar (size_t s)
198 {
199 static_assert (IsMallocable<T>::value, "Trying to use XCNEWVAR with a \
200 non-POD data type.");
201 return XCNEWVAR (T, s);
202 }
203
204 #undef XCNEWVAR
205 #define XCNEWVAR(T, S) xcnewvar<T> (S)
206
207 template<typename T>
208 static T *
209 xresizevar (T *p, size_t s)
210 {
211 static_assert (IsMallocable<T>::value, "Trying to use XRESIZEVAR with a \
212 non-POD data type.");
213 return XRESIZEVAR (T, p, s);
214 }
215
216 #undef XRESIZEVAR
217 #define XRESIZEVAR(T, P, S) xresizevar<T> (P, S)
218
219 #endif /* COMMON_POISON_H */
XNEWVAR
#define XNEWVAR(T, S)
Definition: poison.h:193
xdeletevec
static void xdeletevec(T *p)
Definition: poison.h:173
xnewvec
static T * xnewvec(size_t n)
Definition: poison.h:137
XCNEWVAR
#define XCNEWVAR(T, S)
Definition: poison.h:205
xdelete
static void xdelete(T *p)
Definition: poison.h:125
memset
void * memset(T *s, int c, size_t n)=delete
xcnewvec
static T * xcnewvec(size_t n)
Definition: poison.h:149
traits.h
XNEW
#define XNEW(T)
Definition: poison.h:109
XCNEWVEC
#define XCNEWVEC(T, N)
Definition: poison.h:157
xresizevec
static T * xresizevec(T *p, size_t n)
Definition: poison.h:161
IsMemsettable
Definition: poison.h:49
xnewvar
static T * xnewvar(size_t s)
Definition: poison.h:185
gdb::And
Definition: traits.h:76
gdb::Or
Definition: traits.h:55
free
void free(T *ptr)=delete
XDELETE
#define XDELETE(P)
Definition: poison.h:133
XRESIZEVEC
#define XRESIZEVEC(T, P, N)
Definition: poison.h:169
xcnewvar
static T * xcnewvar(size_t s)
Definition: poison.h:197
gdb::Requires
typename std::enable_if< Condition::value, void >::type Requires
Definition: traits.h:98
XNEWVEC
#define XNEWVEC(T, N)
Definition: poison.h:145
XCNEW
#define XCNEW(T)
Definition: poison.h:121
XRESIZEVAR
#define XRESIZEVAR(T, P, S)
Definition: poison.h:217
xnew
static T * xnew()
Definition: poison.h:101
xcnew
static T * xcnew()
Definition: poison.h:113
xresizevar
static T * xresizevar(T *p, size_t s)
Definition: poison.h:209
XDELETEVEC
#define XDELETEVEC(P)
Definition: poison.h:181
IsMallocable
std::is_pod< T > IsMallocable
Definition: poison.h:91