1 /* intprops-internal.h -- properties of integer types not visible to users
2
3 Copyright (C) 2001-2023 Free Software Foundation, Inc.
4
5 This program is free software: you can redistribute it and/or modify it
6 under the terms of the GNU Lesser General Public License as published
7 by the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
17
18 #ifndef _GL_INTPROPS_INTERNAL_H
19 #define _GL_INTPROPS_INTERNAL_H
20
21 #include <limits.h>
22
23 /* Return a value with the common real type of E and V and the value of V.
24 Do not evaluate E. */
25 #define _GL_INT_CONVERT(e, v) ((1 ? 0 : (e)) + (v))
26
27 /* Act like _GL_INT_CONVERT (E, -V) but work around a bug in IRIX 6.5 cc; see
28 <https://lists.gnu.org/r/bug-gnulib/2011-05/msg00406.html>. */
29 #define _GL_INT_NEGATE_CONVERT(e, v) ((1 ? 0 : (e)) - (v))
30
31 /* The extra casts in the following macros work around compiler bugs,
32 e.g., in Cray C 5.0.3.0. */
33
34 /* True if the real type T is signed. */
35 #define _GL_TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
36
37 /* Return 1 if the real expression E, after promotion, has a
38 signed or floating type. Do not evaluate E. */
39 #define _GL_EXPR_SIGNED(e) (_GL_INT_NEGATE_CONVERT (e, 1) < 0)
40
41
42 /* Minimum and maximum values for integer types and expressions. */
43
44 /* The width in bits of the integer type or expression T.
45 Do not evaluate T. T must not be a bit-field expression.
46 Padding bits are not supported; this is checked at compile-time below. */
47 #define _GL_TYPE_WIDTH(t) (sizeof (t) * CHAR_BIT)
48
49 /* The maximum and minimum values for the type of the expression E,
50 after integer promotion. E is not evaluated. */
51 #define _GL_INT_MINIMUM(e) \
52 (_GL_EXPR_SIGNED (e) \
53 ? ~ _GL_SIGNED_INT_MAXIMUM (e) \
54 : _GL_INT_CONVERT (e, 0))
55 #define _GL_INT_MAXIMUM(e) \
56 (_GL_EXPR_SIGNED (e) \
57 ? _GL_SIGNED_INT_MAXIMUM (e) \
58 : _GL_INT_NEGATE_CONVERT (e, 1))
59 #define _GL_SIGNED_INT_MAXIMUM(e) \
60 (((_GL_INT_CONVERT (e, 1) << (_GL_TYPE_WIDTH (+ (e)) - 2)) - 1) * 2 + 1)
61
62 /* Work around OpenVMS incompatibility with C99. */
63 #if !defined LLONG_MAX && defined __INT64_MAX
64 # define LLONG_MAX __INT64_MAX
65 # define LLONG_MIN __INT64_MIN
66 #endif
67
68 /* This include file assumes that signed types are two's complement without
69 padding bits; the above macros have undefined behavior otherwise.
70 If this is a problem for you, please let us know how to fix it for your host.
71 This assumption is tested by the intprops-tests module. */
72
73 /* Does the __typeof__ keyword work? This could be done by
74 'configure', but for now it's easier to do it by hand. */
75 #if (2 <= __GNUC__ \
76 || (4 <= __clang_major__) \
77 || (1210 <= __IBMC__ && defined __IBM__TYPEOF__) \
78 || (0x5110 <= __SUNPRO_C && !__STDC__))
79 # define _GL_HAVE___TYPEOF__ 1
80 #else
81 # define _GL_HAVE___TYPEOF__ 0
82 #endif
83
84 /* Return 1 if the integer type or expression T might be signed. Return 0
85 if it is definitely unsigned. T must not be a bit-field expression.
86 This macro does not evaluate its argument, and expands to an
87 integer constant expression. */
88 #if _GL_HAVE___TYPEOF__
89 # define _GL_SIGNED_TYPE_OR_EXPR(t) _GL_TYPE_SIGNED (__typeof__ (t))
90 #else
91 # define _GL_SIGNED_TYPE_OR_EXPR(t) 1
92 #endif
93
94 /* Return 1 if - A would overflow in [MIN,MAX] arithmetic.
95 A should not have side effects, and A's type should be an
96 integer with minimum value MIN and maximum MAX. */
97 #define _GL_INT_NEGATE_RANGE_OVERFLOW(a, min, max) \
98 ((min) < 0 ? (a) < - (max) : 0 < (a))
99
100 /* True if __builtin_add_overflow (A, B, P) and __builtin_sub_overflow
101 (A, B, P) work when P is non-null. */
102 #ifdef __EDG__
103 /* EDG-based compilers like nvc 22.1 cannot add 64-bit signed to unsigned
104 <https://bugs.gnu.org/53256>. */
105 # define _GL_HAS_BUILTIN_ADD_OVERFLOW 0
106 #elif defined __has_builtin
107 # define _GL_HAS_BUILTIN_ADD_OVERFLOW __has_builtin (__builtin_add_overflow)
108 /* __builtin_{add,sub}_overflow exists but is not reliable in GCC 5.x and 6.x,
109 see <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98269>. */
110 #elif 7 <= __GNUC__
111 # define _GL_HAS_BUILTIN_ADD_OVERFLOW 1
112 #else
113 # define _GL_HAS_BUILTIN_ADD_OVERFLOW 0
114 #endif
115
116 /* True if __builtin_mul_overflow (A, B, P) works when P is non-null. */
117 #if defined __clang_major__ && __clang_major__ < 14
118 /* Work around Clang bug <https://bugs.llvm.org/show_bug.cgi?id=16404>. */
119 # define _GL_HAS_BUILTIN_MUL_OVERFLOW 0
120 #else
121 # define _GL_HAS_BUILTIN_MUL_OVERFLOW _GL_HAS_BUILTIN_ADD_OVERFLOW
122 #endif
123
124 /* True if __builtin_add_overflow_p (A, B, C) works, and similarly for
125 __builtin_sub_overflow_p and __builtin_mul_overflow_p. */
126 #ifdef __EDG__
127 /* In EDG-based compilers like ICC 2021.3 and earlier,
128 __builtin_add_overflow_p etc. are not treated as integral constant
129 expressions even when all arguments are. */
130 # define _GL_HAS_BUILTIN_OVERFLOW_P 0
131 #elif defined __has_builtin
132 # define _GL_HAS_BUILTIN_OVERFLOW_P __has_builtin (__builtin_mul_overflow_p)
133 #else
134 # define _GL_HAS_BUILTIN_OVERFLOW_P (7 <= __GNUC__)
135 #endif
136
137 #if (!defined _GL_STDCKDINT_H && 202311 <= __STDC_VERSION__ \
138 && ! (_GL_HAS_BUILTIN_ADD_OVERFLOW && _GL_HAS_BUILTIN_MUL_OVERFLOW))
139 # include <stdckdint.h>
140 #endif
141
142 /* Store the low-order bits of A + B, A - B, A * B, respectively, into *R.
143 Return 1 if the result overflows. Arguments should not have side
144 effects and A, B and *R can be of any integer type other than char,
145 bool, a bit-precise integer type, or an enumeration type. */
146 #if _GL_HAS_BUILTIN_ADD_OVERFLOW
147 # define _GL_INT_ADD_WRAPV(a, b, r) __builtin_add_overflow (a, b, r)
148 # define _GL_INT_SUBTRACT_WRAPV(a, b, r) __builtin_sub_overflow (a, b, r)
149 #elif defined ckd_add && defined ckd_sub && !defined _GL_STDCKDINT_H
150 # define _GL_INT_ADD_WRAPV(a, b, r) ckd_add (r, + (a), + (b))
151 # define _GL_INT_SUBTRACT_WRAPV(a, b, r) ckd_sub (r, + (a), + (b))
152 #else
153 # define _GL_INT_ADD_WRAPV(a, b, r) \
154 _GL_INT_OP_WRAPV (a, b, r, +, _GL_INT_ADD_RANGE_OVERFLOW)
155 # define _GL_INT_SUBTRACT_WRAPV(a, b, r) \
156 _GL_INT_OP_WRAPV (a, b, r, -, _GL_INT_SUBTRACT_RANGE_OVERFLOW)
157 #endif
158 #if _GL_HAS_BUILTIN_MUL_OVERFLOW
159 # if ((9 < __GNUC__ + (3 <= __GNUC_MINOR__) \
160 || (__GNUC__ == 8 && 4 <= __GNUC_MINOR__)) \
161 && !defined __EDG__)
162 # define _GL_INT_MULTIPLY_WRAPV(a, b, r) __builtin_mul_overflow (a, b, r)
163 # else
164 /* Work around GCC bug 91450. */
165 # define _GL_INT_MULTIPLY_WRAPV(a, b, r) \
166 ((!_GL_SIGNED_TYPE_OR_EXPR (*(r)) && _GL_EXPR_SIGNED (a) && _GL_EXPR_SIGNED (b) \
167 && _GL_INT_MULTIPLY_RANGE_OVERFLOW (a, b, 0, (__typeof__ (*(r))) -1)) \
168 ? ((void) __builtin_mul_overflow (a, b, r), 1) \
169 : __builtin_mul_overflow (a, b, r))
170 # endif
171 #elif defined ckd_mul && !defined _GL_STDCKDINT_H
172 # define _GL_INT_MULTIPLY_WRAPV(a, b, r) ckd_mul (r, + (a), + (b))
173 #else
174 # define _GL_INT_MULTIPLY_WRAPV(a, b, r) \
175 _GL_INT_OP_WRAPV (a, b, r, *, _GL_INT_MULTIPLY_RANGE_OVERFLOW)
176 #endif
177
178 /* Nonzero if this compiler has GCC bug 68193 or Clang bug 25390. See:
179 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68193
180 https://llvm.org/bugs/show_bug.cgi?id=25390
181 For now, assume all versions of GCC-like compilers generate bogus
182 warnings for _Generic. This matters only for compilers that
183 lack relevant builtins. */
184 #if __GNUC__ || defined __clang__
185 # define _GL__GENERIC_BOGUS 1
186 #else
187 # define _GL__GENERIC_BOGUS 0
188 #endif
189
190 /* Store the low-order bits of A <op> B into *R, where OP specifies
191 the operation and OVERFLOW the overflow predicate. Return 1 if the
192 result overflows. Arguments should not have side effects,
193 and A, B and *R can be of any integer type other than char, bool, a
194 bit-precise integer type, or an enumeration type. */
195 #if 201112 <= __STDC_VERSION__ && !_GL__GENERIC_BOGUS
196 # define _GL_INT_OP_WRAPV(a, b, r, op, overflow) \
197 (_Generic \
198 (*(r), \
199 signed char: \
200 _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
201 signed char, SCHAR_MIN, SCHAR_MAX), \
202 unsigned char: \
203 _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
204 unsigned char, 0, UCHAR_MAX), \
205 short int: \
206 _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
207 short int, SHRT_MIN, SHRT_MAX), \
208 unsigned short int: \
209 _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
210 unsigned short int, 0, USHRT_MAX), \
211 int: \
212 _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
213 int, INT_MIN, INT_MAX), \
214 unsigned int: \
215 _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
216 unsigned int, 0, UINT_MAX), \
217 long int: \
218 _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
219 long int, LONG_MIN, LONG_MAX), \
220 unsigned long int: \
221 _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
222 unsigned long int, 0, ULONG_MAX), \
223 long long int: \
224 _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
225 long long int, LLONG_MIN, LLONG_MAX), \
226 unsigned long long int: \
227 _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
228 unsigned long long int, 0, ULLONG_MAX)))
229 #else
230 /* Store the low-order bits of A <op> B into *R, where OP specifies
231 the operation and OVERFLOW the overflow predicate. If *R is
232 signed, its type is ST with bounds SMIN..SMAX; otherwise its type
233 is UT with bounds U..UMAX. ST and UT are narrower than int.
234 Return 1 if the result overflows. Arguments should not have side
235 effects, and A, B and *R can be of any integer type other than
236 char, bool, a bit-precise integer type, or an enumeration type. */
237 # if _GL_HAVE___TYPEOF__
238 # define _GL_INT_OP_WRAPV_SMALLISH(a,b,r,op,overflow,st,smin,smax,ut,umax) \
239 (_GL_TYPE_SIGNED (__typeof__ (*(r))) \
240 ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, st, smin, smax) \
241 : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, ut, 0, umax))
242 # else
243 # define _GL_INT_OP_WRAPV_SMALLISH(a,b,r,op,overflow,st,smin,smax,ut,umax) \
244 (overflow (a, b, smin, smax) \
245 ? (overflow (a, b, 0, umax) \
246 ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st), 1) \
247 : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st)) < 0) \
248 : (overflow (a, b, 0, umax) \
249 ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st)) >= 0 \
250 : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st), 0)))
251 # endif
252
253 # define _GL_INT_OP_WRAPV(a, b, r, op, overflow) \
254 (sizeof *(r) == sizeof (signed char) \
255 ? _GL_INT_OP_WRAPV_SMALLISH (a, b, r, op, overflow, \
256 signed char, SCHAR_MIN, SCHAR_MAX, \
257 unsigned char, UCHAR_MAX) \
258 : sizeof *(r) == sizeof (short int) \
259 ? _GL_INT_OP_WRAPV_SMALLISH (a, b, r, op, overflow, \
260 short int, SHRT_MIN, SHRT_MAX, \
261 unsigned short int, USHRT_MAX) \
262 : sizeof *(r) == sizeof (int) \
263 ? (_GL_EXPR_SIGNED (*(r)) \
264 ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
265 int, INT_MIN, INT_MAX) \
266 : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
267 unsigned int, 0, UINT_MAX)) \
268 : _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow))
269 # ifdef LLONG_MAX
270 # define _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow) \
271 (sizeof *(r) == sizeof (long int) \
272 ? (_GL_EXPR_SIGNED (*(r)) \
273 ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
274 long int, LONG_MIN, LONG_MAX) \
275 : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
276 unsigned long int, 0, ULONG_MAX)) \
277 : (_GL_EXPR_SIGNED (*(r)) \
278 ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
279 long long int, LLONG_MIN, LLONG_MAX) \
280 : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
281 unsigned long long int, 0, ULLONG_MAX)))
282 # else
283 # define _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow) \
284 (_GL_EXPR_SIGNED (*(r)) \
285 ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
286 long int, LONG_MIN, LONG_MAX) \
287 : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
288 unsigned long int, 0, ULONG_MAX))
289 # endif
290 #endif
291
292 /* Store the low-order bits of A <op> B into *R, where the operation
293 is given by OP. Use the unsigned type UT for calculation to avoid
294 overflow problems. *R's type is T, with extrema TMIN and TMAX.
295 T can be any signed integer type other than char, bool, a
296 bit-precise integer type, or an enumeration type.
297 Return 1 if the result overflows. */
298 #define _GL_INT_OP_CALC(a, b, r, op, overflow, ut, t, tmin, tmax) \
299 (overflow (a, b, tmin, tmax) \
300 ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t), 1) \
301 : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t), 0))
302
303 /* Return 1 if the integer expressions A - B and -A would overflow,
304 respectively. Arguments should not have side effects,
305 and can be any signed integer type other than char, bool, a
306 bit-precise integer type, or an enumeration type.
307 These macros are tuned for their last input argument being a constant. */
308
309 #if _GL_HAS_BUILTIN_OVERFLOW_P
310 # define _GL_INT_NEGATE_OVERFLOW(a) \
311 __builtin_sub_overflow_p (0, a, (__typeof__ (- (a))) 0)
312 #else
313 # define _GL_INT_NEGATE_OVERFLOW(a) \
314 _GL_INT_NEGATE_RANGE_OVERFLOW (a, _GL_INT_MINIMUM (a), _GL_INT_MAXIMUM (a))
315 #endif
316
317 /* Return the low-order bits of A <op> B, where the operation is given
318 by OP. Use the unsigned type UT for calculation to avoid undefined
319 behavior on signed integer overflow, and convert the result to type T.
320 UT is at least as wide as T and is no narrower than unsigned int,
321 T is two's complement, and there is no padding or trap representations.
322 Assume that converting UT to T yields the low-order bits, as is
323 done in all known two's-complement C compilers. E.g., see:
324 https://gcc.gnu.org/onlinedocs/gcc/Integers-implementation.html
325
326 According to the C standard, converting UT to T yields an
327 implementation-defined result or signal for values outside T's
328 range. However, code that works around this theoretical problem
329 runs afoul of a compiler bug in Oracle Studio 12.3 x86. See:
330 https://lists.gnu.org/r/bug-gnulib/2017-04/msg00049.html
331 As the compiler bug is real, don't try to work around the
332 theoretical problem. */
333
334 #define _GL_INT_OP_WRAPV_VIA_UNSIGNED(a, b, op, ut, t) \
335 ((t) ((ut) (a) op (ut) (b)))
336
337 /* Return true if the numeric values A + B, A - B, A * B fall outside
338 the range TMIN..TMAX. Arguments should not have side effects
339 and can be any integer type other than char, bool,
340 a bit-precise integer type, or an enumeration type.
341 TMIN should be signed and nonpositive.
342 TMAX should be positive, and should be signed unless TMIN is zero. */
343 #define _GL_INT_ADD_RANGE_OVERFLOW(a, b, tmin, tmax) \
344 ((b) < 0 \
345 ? (((tmin) \
346 ? ((_GL_EXPR_SIGNED (_GL_INT_CONVERT (a, (tmin) - (b))) || (b) < (tmin)) \
347 && (a) < (tmin) - (b)) \
348 : (a) <= -1 - (b)) \
349 || ((_GL_EXPR_SIGNED (a) ? 0 <= (a) : (tmax) < (a)) && (tmax) < (a) + (b))) \
350 : (a) < 0 \
351 ? (((tmin) \
352 ? ((_GL_EXPR_SIGNED (_GL_INT_CONVERT (b, (tmin) - (a))) || (a) < (tmin)) \
353 && (b) < (tmin) - (a)) \
354 : (b) <= -1 - (a)) \
355 || ((_GL_EXPR_SIGNED (_GL_INT_CONVERT (a, b)) || (tmax) < (b)) \
356 && (tmax) < (a) + (b))) \
357 : (tmax) < (b) || (tmax) - (b) < (a))
358 #define _GL_INT_SUBTRACT_RANGE_OVERFLOW(a, b, tmin, tmax) \
359 (((a) < 0) == ((b) < 0) \
360 ? ((a) < (b) \
361 ? !(tmin) || -1 - (tmin) < (b) - (a) - 1 \
362 : (tmax) < (a) - (b)) \
363 : (a) < 0 \
364 ? ((!_GL_EXPR_SIGNED (_GL_INT_CONVERT ((a) - (tmin), b)) && (a) - (tmin) < 0) \
365 || (a) - (tmin) < (b)) \
366 : ((! (_GL_EXPR_SIGNED (_GL_INT_CONVERT (tmax, b)) \
367 && _GL_EXPR_SIGNED (_GL_INT_CONVERT ((tmax) + (b), a))) \
368 && (tmax) <= -1 - (b)) \
369 || (tmax) + (b) < (a)))
370 #define _GL_INT_MULTIPLY_RANGE_OVERFLOW(a, b, tmin, tmax) \
371 ((b) < 0 \
372 ? ((a) < 0 \
373 ? (_GL_EXPR_SIGNED (_GL_INT_CONVERT (tmax, b)) \
374 ? (a) < (tmax) / (b) \
375 : ((_GL_INT_NEGATE_OVERFLOW (b) \
376 ? _GL_INT_CONVERT (b, tmax) >> (_GL_TYPE_WIDTH (+ (b)) - 1) \
377 : (tmax) / -(b)) \
378 <= -1 - (a))) \
379 : _GL_INT_NEGATE_OVERFLOW (_GL_INT_CONVERT (b, tmin)) && (b) == -1 \
380 ? (_GL_EXPR_SIGNED (a) \
381 ? 0 < (a) + (tmin) \
382 : 0 < (a) && -1 - (tmin) < (a) - 1) \
383 : (tmin) / (b) < (a)) \
384 : (b) == 0 \
385 ? 0 \
386 : ((a) < 0 \
387 ? (_GL_INT_NEGATE_OVERFLOW (_GL_INT_CONVERT (a, tmin)) && (a) == -1 \
388 ? (_GL_EXPR_SIGNED (b) ? 0 < (b) + (tmin) : -1 - (tmin) < (b) - 1) \
389 : (tmin) / (a) < (b)) \
390 : (tmax) / (b) < (a)))
391
392 #endif /* _GL_INTPROPS_INTERNAL_H */