| 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 | #include "obstack.h" |
| 25 | |
| 26 | /* Poison memset of non-POD types. The idea is catching invalid |
| 27 | initialization of non-POD structs that is easy to be introduced as |
| 28 | side effect of refactoring. For example, say this: |
| 29 | |
| 30 | struct S { VEC(foo_s) *m_data; }; |
| 31 | |
| 32 | is converted to this at some point: |
| 33 | |
| 34 | struct S { |
| 35 | S() { m_data.reserve (10); } |
| 36 | std::vector<foo> m_data; |
| 37 | }; |
| 38 | |
| 39 | and old code was initializing S objects like this: |
| 40 | |
| 41 | struct S s; |
| 42 | memset (&s, 0, sizeof (S)); // whoops, now wipes vector. |
| 43 | |
| 44 | Declaring memset as deleted for non-POD types makes the memset above |
| 45 | be a compile-time error. */ |
| 46 | |
| 47 | /* Helper for SFINAE. True if "T *" is memsettable. I.e., if T is |
| 48 | either void, or POD. */ |
| 49 | template<typename T> |
| 50 | struct IsMemsettable |
| 51 | : gdb::Or<std::is_void<T>, |
| 52 | std::is_pod<T>> |
| 53 | {}; |
| 54 | |
| 55 | template <typename T, |
| 56 | typename = gdb::Requires<gdb::Not<IsMemsettable<T>>>> |
| 57 | void *memset (T *s, int c, size_t n) = delete; |
| 58 | |
| 59 | #if HAVE_IS_TRIVIALLY_COPYABLE |
| 60 | |
| 61 | /* Similarly, poison memcpy and memmove of non trivially-copyable |
| 62 | types, which is undefined. */ |
| 63 | |
| 64 | /* True if "T *" is relocatable. I.e., copyable with memcpy/memmove. |
| 65 | I.e., T is either trivially copyable, or void. */ |
| 66 | template<typename T> |
| 67 | struct IsRelocatable |
| 68 | : gdb::Or<std::is_void<T>, |
| 69 | std::is_trivially_copyable<T>> |
| 70 | {}; |
| 71 | |
| 72 | /* True if both source and destination are relocatable. */ |
| 73 | |
| 74 | template <typename D, typename S> |
| 75 | using BothAreRelocatable |
| 76 | = gdb::And<IsRelocatable<D>, IsRelocatable<S>>; |
| 77 | |
| 78 | template <typename D, typename S, |
| 79 | typename = gdb::Requires<gdb::Not<BothAreRelocatable<D, S>>>> |
| 80 | void *memcpy (D *dest, const S *src, size_t n) = delete; |
| 81 | |
| 82 | template <typename D, typename S, |
| 83 | typename = gdb::Requires<gdb::Not<BothAreRelocatable<D, S>>>> |
| 84 | void *memmove (D *dest, const S *src, size_t n) = delete; |
| 85 | |
| 86 | #endif /* HAVE_IS_TRIVIALLY_COPYABLE */ |
| 87 | |
| 88 | /* Poison XNEW and friends to catch usages of malloc-style allocations on |
| 89 | objects that require new/delete. */ |
| 90 | |
| 91 | template<typename T> |
| 92 | #if HAVE_IS_TRIVIALLY_CONSTRUCTIBLE |
| 93 | using IsMallocable = std::is_trivially_constructible<T>; |
| 94 | #else |
| 95 | using IsMallocable = std::true_type; |
| 96 | #endif |
| 97 | |
| 98 | template<typename T> |
| 99 | using IsFreeable = gdb::Or<std::is_trivially_destructible<T>, std::is_void<T>>; |
| 100 | |
| 101 | template <typename T, typename = gdb::Requires<gdb::Not<IsFreeable<T>>>> |
| 102 | void free (T *ptr) = delete; |
| 103 | |
| 104 | template<typename T> |
| 105 | static T * |
| 106 | xnew () |
| 107 | { |
| 108 | static_assert (IsMallocable<T>::value, "Trying to use XNEW with a non-POD \ |
| 109 | data type. Use operator new instead."); |
| 110 | return XNEW (T); |
| 111 | } |
| 112 | |
| 113 | #undef XNEW |
| 114 | #define XNEW(T) xnew<T>() |
| 115 | |
| 116 | template<typename T> |
| 117 | static T * |
| 118 | xcnew () |
| 119 | { |
| 120 | static_assert (IsMallocable<T>::value, "Trying to use XCNEW with a non-POD \ |
| 121 | data type. Use operator new instead."); |
| 122 | return XCNEW (T); |
| 123 | } |
| 124 | |
| 125 | #undef XCNEW |
| 126 | #define XCNEW(T) xcnew<T>() |
| 127 | |
| 128 | template<typename T> |
| 129 | static void |
| 130 | xdelete (T *p) |
| 131 | { |
| 132 | static_assert (IsFreeable<T>::value, "Trying to use XDELETE with a non-POD \ |
| 133 | data type. Use operator delete instead."); |
| 134 | XDELETE (p); |
| 135 | } |
| 136 | |
| 137 | #undef XDELETE |
| 138 | #define XDELETE(P) xdelete (P) |
| 139 | |
| 140 | template<typename T> |
| 141 | static T * |
| 142 | xnewvec (size_t n) |
| 143 | { |
| 144 | static_assert (IsMallocable<T>::value, "Trying to use XNEWVEC with a \ |
| 145 | non-POD data type. Use operator new[] (or std::vector) instead."); |
| 146 | return XNEWVEC (T, n); |
| 147 | } |
| 148 | |
| 149 | #undef XNEWVEC |
| 150 | #define XNEWVEC(T, N) xnewvec<T> (N) |
| 151 | |
| 152 | template<typename T> |
| 153 | static T * |
| 154 | xcnewvec (size_t n) |
| 155 | { |
| 156 | static_assert (IsMallocable<T>::value, "Trying to use XCNEWVEC with a \ |
| 157 | non-POD data type. Use operator new[] (or std::vector) instead."); |
| 158 | return XCNEWVEC (T, n); |
| 159 | } |
| 160 | |
| 161 | #undef XCNEWVEC |
| 162 | #define XCNEWVEC(T, N) xcnewvec<T> (N) |
| 163 | |
| 164 | template<typename T> |
| 165 | static T * |
| 166 | xresizevec (T *p, size_t n) |
| 167 | { |
| 168 | static_assert (IsMallocable<T>::value, "Trying to use XRESIZEVEC with a \ |
| 169 | non-POD data type."); |
| 170 | return XRESIZEVEC (T, p, n); |
| 171 | } |
| 172 | |
| 173 | #undef XRESIZEVEC |
| 174 | #define XRESIZEVEC(T, P, N) xresizevec<T> (P, N) |
| 175 | |
| 176 | template<typename T> |
| 177 | static void |
| 178 | xdeletevec (T *p) |
| 179 | { |
| 180 | static_assert (IsFreeable<T>::value, "Trying to use XDELETEVEC with a \ |
| 181 | non-POD data type. Use operator delete[] (or std::vector) instead."); |
| 182 | XDELETEVEC (p); |
| 183 | } |
| 184 | |
| 185 | #undef XDELETEVEC |
| 186 | #define XDELETEVEC(P) xdeletevec (P) |
| 187 | |
| 188 | template<typename T> |
| 189 | static T * |
| 190 | xnewvar (size_t s) |
| 191 | { |
| 192 | static_assert (IsMallocable<T>::value, "Trying to use XNEWVAR with a \ |
| 193 | non-POD data type."); |
| 194 | return XNEWVAR (T, s);; |
| 195 | } |
| 196 | |
| 197 | #undef XNEWVAR |
| 198 | #define XNEWVAR(T, S) xnewvar<T> (S) |
| 199 | |
| 200 | template<typename T> |
| 201 | static T * |
| 202 | xcnewvar (size_t s) |
| 203 | { |
| 204 | static_assert (IsMallocable<T>::value, "Trying to use XCNEWVAR with a \ |
| 205 | non-POD data type."); |
| 206 | return XCNEWVAR (T, s); |
| 207 | } |
| 208 | |
| 209 | #undef XCNEWVAR |
| 210 | #define XCNEWVAR(T, S) xcnewvar<T> (S) |
| 211 | |
| 212 | template<typename T> |
| 213 | static T * |
| 214 | xresizevar (T *p, size_t s) |
| 215 | { |
| 216 | static_assert (IsMallocable<T>::value, "Trying to use XRESIZEVAR with a \ |
| 217 | non-POD data type."); |
| 218 | return XRESIZEVAR (T, p, s); |
| 219 | } |
| 220 | |
| 221 | #undef XRESIZEVAR |
| 222 | #define XRESIZEVAR(T, P, S) xresizevar<T> (P, S) |
| 223 | |
| 224 | template<typename T> |
| 225 | static T * |
| 226 | xobnew (obstack *ob) |
| 227 | { |
| 228 | static_assert (IsMallocable<T>::value, "Trying to use XOBNEW with a \ |
| 229 | non-POD data type."); |
| 230 | return XOBNEW (ob, T); |
| 231 | } |
| 232 | |
| 233 | #undef XOBNEW |
| 234 | #define XOBNEW(O, T) xobnew<T> (O) |
| 235 | |
| 236 | template<typename T> |
| 237 | static T * |
| 238 | xobnewvec (obstack *ob, size_t n) |
| 239 | { |
| 240 | static_assert (IsMallocable<T>::value, "Trying to use XOBNEWVEC with a \ |
| 241 | non-POD data type."); |
| 242 | return XOBNEWVEC (ob, T, n); |
| 243 | } |
| 244 | |
| 245 | #undef XOBNEWVEC |
| 246 | #define XOBNEWVEC(O, T, N) xobnewvec<T> (O, N) |
| 247 | |
| 248 | #endif /* COMMON_POISON_H */ |