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b811d2c2 | 1 | /* Copyright (C) 2015-2020 Free Software Foundation, Inc. |
8d297bbf PA |
2 | |
3 | This file is part of GDB. | |
4 | ||
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 3 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | #ifndef COMMON_ENUM_FLAGS_H | |
19 | #define COMMON_ENUM_FLAGS_H | |
20 | ||
04902b09 PA |
21 | #include "traits.h" |
22 | ||
8d297bbf PA |
23 | /* Type-safe wrapper for enum flags. enum flags are enums where the |
24 | values are bits that are meant to be ORed together. | |
25 | ||
26 | This allows writing code like the below, while with raw enums this | |
27 | would fail to compile without casts to enum type at the assignments | |
28 | to 'f': | |
29 | ||
30 | enum some_flag | |
31 | { | |
32 | flag_val1 = 1 << 1, | |
33 | flag_val2 = 1 << 2, | |
34 | flag_val3 = 1 << 3, | |
35 | flag_val4 = 1 << 4, | |
36 | }; | |
115f7325 | 37 | DEF_ENUM_FLAGS_TYPE(enum some_flag, some_flags); |
8d297bbf PA |
38 | |
39 | some_flags f = flag_val1 | flag_val2; | |
40 | f |= flag_val3; | |
41 | ||
42 | It's also possible to assign literal zero to an enum flags variable | |
43 | (meaning, no flags), dispensing adding an awkward explicit "no | |
44 | value" value to the enumeration. For example: | |
45 | ||
46 | some_flags f = 0; | |
47 | f |= flag_val3 | flag_val4; | |
48 | ||
49 | Note that literal integers other than zero fail to compile: | |
50 | ||
51 | some_flags f = 1; // error | |
52 | */ | |
53 | ||
54 | #ifdef __cplusplus | |
55 | ||
04902b09 | 56 | /* Use this to mark an enum as flags enum. It defines FLAGS_TYPE as |
8d297bbf PA |
57 | enum_flags wrapper class for ENUM, and enables the global operator |
58 | overloads for ENUM. */ | |
59 | #define DEF_ENUM_FLAGS_TYPE(enum_type, flags_type) \ | |
60 | typedef enum_flags<enum_type> flags_type; \ | |
04902b09 PA |
61 | void is_enum_flags_enum_type (enum_type *) |
62 | ||
63 | /* To enable the global enum_flags operators for enum, declare an | |
64 | "is_enum_flags_enum_type" overload that has exactly one parameter, | |
65 | of type a pointer to that enum class. E.g.,: | |
66 | ||
67 | void is_enum_flags_enum_type (enum some_flag *); | |
68 | ||
69 | The function does not need to be defined, only declared. | |
70 | DEF_ENUM_FLAGS_TYPE declares this. | |
71 | ||
72 | A function declaration is preferred over a traits type, because the | |
73 | former allows calling the DEF_ENUM_FLAGS_TYPE macro inside a | |
74 | namespace to define the corresponding enum flags type in that | |
75 | namespace. The compiler finds the corresponding | |
76 | is_enum_flags_enum_type function via ADL. */ | |
8d297bbf | 77 | |
04902b09 PA |
78 | /* Note that std::underlying_type<enum_type> is not what we want here, |
79 | since that returns unsigned int even when the enum decays to signed | |
80 | int. */ | |
8d297bbf PA |
81 | template<int size, bool sign> class integer_for_size { typedef void type; }; |
82 | template<> struct integer_for_size<1, 0> { typedef uint8_t type; }; | |
83 | template<> struct integer_for_size<2, 0> { typedef uint16_t type; }; | |
84 | template<> struct integer_for_size<4, 0> { typedef uint32_t type; }; | |
85 | template<> struct integer_for_size<8, 0> { typedef uint64_t type; }; | |
86 | template<> struct integer_for_size<1, 1> { typedef int8_t type; }; | |
87 | template<> struct integer_for_size<2, 1> { typedef int16_t type; }; | |
88 | template<> struct integer_for_size<4, 1> { typedef int32_t type; }; | |
89 | template<> struct integer_for_size<8, 1> { typedef int64_t type; }; | |
90 | ||
91 | template<typename T> | |
92 | struct enum_underlying_type | |
93 | { | |
94 | typedef typename | |
95 | integer_for_size<sizeof (T), static_cast<bool>(T (-1) < T (0))>::type | |
96 | type; | |
97 | }; | |
98 | ||
04902b09 | 99 | namespace enum_flags_detail |
8d297bbf | 100 | { |
8d297bbf | 101 | |
04902b09 | 102 | /* Private type used to support initializing flag types with zero: |
8d297bbf | 103 | |
04902b09 | 104 | foo_flags f = 0; |
8d297bbf | 105 | |
04902b09 | 106 | but not other integers: |
8d297bbf | 107 | |
04902b09 | 108 | foo_flags f = 1; |
8d297bbf | 109 | |
04902b09 PA |
110 | The way this works is that we define an implicit constructor that |
111 | takes a pointer to this private type. Since nothing can | |
112 | instantiate an object of this type, the only possible pointer to | |
113 | pass to the constructor is the NULL pointer, or, zero. */ | |
114 | struct zero_type; | |
8d297bbf | 115 | |
04902b09 PA |
116 | /* gdb::Requires trait helpers. */ |
117 | template <typename enum_type> | |
118 | using EnumIsUnsigned | |
119 | = std::is_unsigned<typename enum_underlying_type<enum_type>::type>; | |
120 | template <typename enum_type> | |
121 | using EnumIsSigned | |
122 | = std::is_signed<typename enum_underlying_type<enum_type>::type>; | |
123 | ||
124 | } | |
125 | ||
126 | template <typename E> | |
127 | class enum_flags | |
128 | { | |
129 | public: | |
130 | typedef E enum_type; | |
131 | typedef typename enum_underlying_type<enum_type>::type underlying_type; | |
8d297bbf PA |
132 | |
133 | public: | |
1b90b139 | 134 | /* Allow default construction. */ |
04902b09 | 135 | constexpr enum_flags () |
1b90b139 | 136 | : m_enum_value ((enum_type) 0) |
8d297bbf PA |
137 | {} |
138 | ||
04902b09 PA |
139 | /* The default move/copy ctor/assignment do the right thing. */ |
140 | ||
8d297bbf PA |
141 | /* If you get an error saying these two overloads are ambiguous, |
142 | then you tried to mix values of different enum types. */ | |
04902b09 | 143 | constexpr enum_flags (enum_type e) |
8d297bbf PA |
144 | : m_enum_value (e) |
145 | {} | |
04902b09 | 146 | constexpr enum_flags (enum_flags_detail::zero_type *zero) |
8d297bbf PA |
147 | : m_enum_value ((enum_type) 0) |
148 | {} | |
149 | ||
04902b09 | 150 | enum_flags &operator&= (enum_flags e) & |
8d297bbf | 151 | { |
04902b09 | 152 | m_enum_value = (enum_type) (m_enum_value & e.m_enum_value); |
8d297bbf PA |
153 | return *this; |
154 | } | |
04902b09 | 155 | enum_flags &operator|= (enum_flags e) & |
8d297bbf | 156 | { |
04902b09 | 157 | m_enum_value = (enum_type) (m_enum_value | e.m_enum_value); |
8d297bbf PA |
158 | return *this; |
159 | } | |
04902b09 | 160 | enum_flags &operator^= (enum_flags e) & |
8d297bbf | 161 | { |
04902b09 | 162 | m_enum_value = (enum_type) (m_enum_value ^ e.m_enum_value); |
8d297bbf PA |
163 | return *this; |
164 | } | |
165 | ||
04902b09 PA |
166 | /* Delete rval versions. */ |
167 | void operator&= (enum_flags e) && = delete; | |
168 | void operator|= (enum_flags e) && = delete; | |
169 | void operator^= (enum_flags e) && = delete; | |
170 | ||
171 | /* Like raw enums, allow conversion to the underlying type. */ | |
172 | constexpr operator underlying_type () const | |
8d297bbf PA |
173 | { |
174 | return m_enum_value; | |
175 | } | |
176 | ||
04902b09 PA |
177 | /* Get the underlying value as a raw enum. */ |
178 | constexpr enum_type raw () const | |
8d297bbf | 179 | { |
04902b09 | 180 | return m_enum_value; |
8d297bbf PA |
181 | } |
182 | ||
04902b09 PA |
183 | /* Binary operations involving some unrelated type (which would be a |
184 | bug) are implemented as non-members, and deleted. */ | |
185 | ||
8d297bbf PA |
186 | private: |
187 | /* Stored as enum_type because GDB knows to print the bit flags | |
188 | neatly if the enum values look like bit flags. */ | |
189 | enum_type m_enum_value; | |
190 | }; | |
191 | ||
04902b09 PA |
192 | template <typename E> |
193 | using is_enum_flags_enum_type_t | |
194 | = decltype (is_enum_flags_enum_type (std::declval<E *> ())); | |
195 | ||
8d297bbf PA |
196 | /* Global operator overloads. */ |
197 | ||
04902b09 PA |
198 | /* Generate binary operators. */ |
199 | ||
200 | #define ENUM_FLAGS_GEN_BINOP(OPERATOR_OP, OP) \ | |
201 | \ | |
202 | /* Raw enum on both LHS/RHS. Returns raw enum type. */ \ | |
203 | template <typename enum_type, \ | |
204 | typename = is_enum_flags_enum_type_t<enum_type>> \ | |
205 | constexpr enum_type \ | |
206 | OPERATOR_OP (enum_type e1, enum_type e2) \ | |
207 | { \ | |
208 | using underlying = typename enum_flags<enum_type>::underlying_type; \ | |
209 | return (enum_type) (underlying (e1) OP underlying (e2)); \ | |
210 | } \ | |
211 | \ | |
212 | /* enum_flags on the LHS. */ \ | |
213 | template <typename enum_type, \ | |
214 | typename = is_enum_flags_enum_type_t<enum_type>> \ | |
215 | constexpr enum_flags<enum_type> \ | |
216 | OPERATOR_OP (enum_flags<enum_type> e1, enum_type e2) \ | |
217 | { return e1.raw () OP e2; } \ | |
218 | \ | |
219 | /* enum_flags on the RHS. */ \ | |
220 | template <typename enum_type, \ | |
221 | typename = is_enum_flags_enum_type_t<enum_type>> \ | |
222 | constexpr enum_flags<enum_type> \ | |
223 | OPERATOR_OP (enum_type e1, enum_flags<enum_type> e2) \ | |
224 | { return e1 OP e2.raw (); } \ | |
225 | \ | |
226 | /* enum_flags on both LHS/RHS. */ \ | |
227 | template <typename enum_type, \ | |
228 | typename = is_enum_flags_enum_type_t<enum_type>> \ | |
229 | constexpr enum_flags<enum_type> \ | |
230 | OPERATOR_OP (enum_flags<enum_type> e1, enum_flags<enum_type> e2) \ | |
231 | { return e1.raw () OP e2.raw (); } \ | |
232 | \ | |
233 | /* Delete cases involving unrelated types. */ \ | |
234 | \ | |
235 | template <typename enum_type, typename unrelated_type, \ | |
236 | typename = is_enum_flags_enum_type_t<enum_type>> \ | |
237 | constexpr enum_flags<enum_type> \ | |
238 | OPERATOR_OP (enum_type e1, unrelated_type e2) = delete; \ | |
239 | \ | |
240 | template <typename enum_type, typename unrelated_type, \ | |
241 | typename = is_enum_flags_enum_type_t<enum_type>> \ | |
242 | constexpr enum_flags<enum_type> \ | |
243 | OPERATOR_OP (unrelated_type e1, enum_type e2) = delete; \ | |
244 | \ | |
245 | template <typename enum_type, typename unrelated_type, \ | |
246 | typename = is_enum_flags_enum_type_t<enum_type>> \ | |
247 | constexpr enum_flags<enum_type> \ | |
248 | OPERATOR_OP (enum_flags<enum_type> e1, unrelated_type e2) = delete; \ | |
249 | \ | |
250 | template <typename enum_type, typename unrelated_type, \ | |
251 | typename = is_enum_flags_enum_type_t<enum_type>> \ | |
252 | constexpr enum_flags<enum_type> \ | |
253 | OPERATOR_OP (unrelated_type e1, enum_flags<enum_type> e2) = delete; | |
254 | ||
255 | /* Generate non-member compound assignment operators. Only the raw | |
256 | enum versions are defined here. The enum_flags versions are | |
257 | defined as member functions, simply because it's less code that | |
258 | way. | |
259 | ||
260 | Note we delete operators that would allow e.g., | |
261 | ||
262 | "enum_type | 1" or "enum_type1 | enum_type2" | |
263 | ||
264 | because that would allow a mistake like : | |
265 | enum flags1 { F1_FLAGS1 = 1 }; | |
266 | enum flags2 { F2_FLAGS2 = 2 }; | |
267 | enum flags1 val; | |
268 | switch (val) { | |
269 | case F1_FLAGS1 | F2_FLAGS2: | |
270 | ... | |
271 | ||
272 | If you really need to 'or' enumerators of different flag types, | |
273 | cast to integer first. | |
274 | */ | |
275 | #define ENUM_FLAGS_GEN_COMPOUND_ASSIGN(OPERATOR_OP, OP) \ | |
276 | /* lval reference version. */ \ | |
277 | template <typename enum_type, \ | |
278 | typename = is_enum_flags_enum_type_t<enum_type>> \ | |
279 | constexpr enum_type & \ | |
280 | OPERATOR_OP (enum_type &e1, enum_type e2) \ | |
281 | { return e1 = e1 OP e2; } \ | |
282 | \ | |
283 | /* rval reference version. */ \ | |
284 | template <typename enum_type, \ | |
285 | typename = is_enum_flags_enum_type_t<enum_type>> \ | |
286 | void \ | |
287 | OPERATOR_OP (enum_type &&e1, enum_type e2) = delete; \ | |
288 | \ | |
289 | /* Delete compound assignment from unrelated types. */ \ | |
290 | \ | |
291 | template <typename enum_type, typename other_enum_type, \ | |
292 | typename = is_enum_flags_enum_type_t<enum_type>> \ | |
293 | constexpr enum_type & \ | |
294 | OPERATOR_OP (enum_type &e1, other_enum_type e2) = delete; \ | |
295 | \ | |
296 | template <typename enum_type, typename other_enum_type, \ | |
297 | typename = is_enum_flags_enum_type_t<enum_type>> \ | |
298 | void \ | |
299 | OPERATOR_OP (enum_type &&e1, other_enum_type e2) = delete; | |
300 | ||
301 | ENUM_FLAGS_GEN_BINOP (operator|, |) | |
302 | ENUM_FLAGS_GEN_BINOP (operator&, &) | |
303 | ENUM_FLAGS_GEN_BINOP (operator^, ^) | |
304 | ||
305 | ENUM_FLAGS_GEN_COMPOUND_ASSIGN (operator|=, |) | |
306 | ENUM_FLAGS_GEN_COMPOUND_ASSIGN (operator&=, &) | |
307 | ENUM_FLAGS_GEN_COMPOUND_ASSIGN (operator^=, ^) | |
308 | ||
309 | /* Allow comparison with enum_flags, raw enum, and integers, only. | |
310 | The latter case allows "== 0". As side effect, it allows comparing | |
311 | with integer variables too, but that's not a common mistake to | |
312 | make. It's important to disable comparison with unrelated types to | |
313 | prevent accidentally comparing with unrelated enum values, which | |
314 | are convertible to integer, and thus coupled with enum_flags | |
315 | convertion to underlying type too, would trigger the built-in 'bool | |
316 | operator==(unsigned, int)' operator. */ | |
317 | ||
318 | #define ENUM_FLAGS_GEN_COMP(OPERATOR_OP, OP) \ | |
319 | \ | |
320 | /* enum_flags OP enum_flags */ \ | |
321 | \ | |
322 | template <typename enum_type> \ | |
323 | constexpr bool \ | |
324 | OPERATOR_OP (enum_flags<enum_type> lhs, enum_flags<enum_type> rhs) \ | |
325 | { return lhs.raw () OP rhs.raw (); } \ | |
326 | \ | |
327 | /* enum_flags OP other */ \ | |
328 | \ | |
329 | template <typename enum_type> \ | |
330 | constexpr bool \ | |
331 | OPERATOR_OP (enum_flags<enum_type> lhs, enum_type rhs) \ | |
332 | { return lhs.raw () OP rhs; } \ | |
333 | \ | |
334 | template <typename enum_type> \ | |
335 | constexpr bool \ | |
336 | OPERATOR_OP (enum_flags<enum_type> lhs, int rhs) \ | |
337 | { return lhs.raw () OP rhs; } \ | |
338 | \ | |
339 | template <typename enum_type, typename U> \ | |
340 | constexpr bool \ | |
341 | OPERATOR_OP (enum_flags<enum_type> lhs, U rhs) = delete; \ | |
342 | \ | |
343 | /* other OP enum_flags */ \ | |
344 | \ | |
345 | template <typename enum_type> \ | |
346 | constexpr bool \ | |
347 | OPERATOR_OP (enum_type lhs, enum_flags<enum_type> rhs) \ | |
348 | { return lhs OP rhs.raw (); } \ | |
349 | \ | |
350 | template <typename enum_type> \ | |
351 | constexpr bool \ | |
352 | OPERATOR_OP (int lhs, enum_flags<enum_type> rhs) \ | |
353 | { return lhs OP rhs.raw (); } \ | |
354 | \ | |
355 | template <typename enum_type, typename U> \ | |
356 | constexpr bool \ | |
357 | OPERATOR_OP (U lhs, enum_flags<enum_type> rhs) = delete; | |
358 | ||
359 | ENUM_FLAGS_GEN_COMP (operator==, ==) | |
360 | ENUM_FLAGS_GEN_COMP (operator!=, !=) | |
361 | ||
362 | /* Unary operators for the raw flags enum. */ | |
363 | ||
364 | /* We require underlying type to be unsigned when using operator~ -- | |
365 | if it were not unsigned, undefined behavior could result. However, | |
366 | asserting this in the class itself would require too many | |
367 | unnecessary changes to usages of otherwise OK enum types. */ | |
368 | template <typename enum_type, | |
369 | typename = is_enum_flags_enum_type_t<enum_type>, | |
370 | typename | |
371 | = gdb::Requires<enum_flags_detail::EnumIsUnsigned<enum_type>>> | |
372 | constexpr enum_type | |
373 | operator~ (enum_type e) | |
8d297bbf | 374 | { |
04902b09 PA |
375 | using underlying = typename enum_flags<enum_type>::underlying_type; |
376 | return (enum_type) ~underlying (e); | |
8d297bbf PA |
377 | } |
378 | ||
04902b09 PA |
379 | template <typename enum_type, |
380 | typename = is_enum_flags_enum_type_t<enum_type>, | |
381 | typename = gdb::Requires<enum_flags_detail::EnumIsSigned<enum_type>>> | |
382 | constexpr void operator~ (enum_type e) = delete; | |
383 | ||
384 | template <typename enum_type, | |
385 | typename = is_enum_flags_enum_type_t<enum_type>, | |
386 | typename | |
387 | = gdb::Requires<enum_flags_detail::EnumIsUnsigned<enum_type>>> | |
388 | constexpr enum_flags<enum_type> | |
389 | operator~ (enum_flags<enum_type> e) | |
8d297bbf | 390 | { |
04902b09 PA |
391 | using underlying = typename enum_flags<enum_type>::underlying_type; |
392 | return (enum_type) ~underlying (e); | |
8d297bbf PA |
393 | } |
394 | ||
04902b09 PA |
395 | template <typename enum_type, |
396 | typename = is_enum_flags_enum_type_t<enum_type>, | |
397 | typename = gdb::Requires<enum_flags_detail::EnumIsSigned<enum_type>>> | |
398 | constexpr void operator~ (enum_flags<enum_type> e) = delete; | |
8d297bbf | 399 | |
04902b09 PA |
400 | /* Delete operator<< and operator>>. */ |
401 | ||
402 | template <typename enum_type, typename any_type, | |
403 | typename = is_enum_flags_enum_type_t<enum_type>> | |
404 | void operator<< (const enum_type &, const any_type &) = delete; | |
405 | ||
406 | template <typename enum_type, typename any_type, | |
407 | typename = is_enum_flags_enum_type_t<enum_type>> | |
408 | void operator<< (const enum_flags<enum_type> &, const any_type &) = delete; | |
409 | ||
410 | template <typename enum_type, typename any_type, | |
411 | typename = is_enum_flags_enum_type_t<enum_type>> | |
412 | void operator>> (const enum_type &, const any_type &) = delete; | |
413 | ||
414 | template <typename enum_type, typename any_type, | |
415 | typename = is_enum_flags_enum_type_t<enum_type>> | |
416 | void operator>> (const enum_flags<enum_type> &, const any_type &) = delete; | |
8d297bbf PA |
417 | |
418 | #else /* __cplusplus */ | |
419 | ||
420 | /* In C, the flags type is just a typedef for the enum type. */ | |
421 | ||
422 | #define DEF_ENUM_FLAGS_TYPE(enum_type, flags_type) \ | |
423 | typedef enum_type flags_type | |
424 | ||
425 | #endif /* __cplusplus */ | |
426 | ||
427 | #endif /* COMMON_ENUM_FLAGS_H */ |