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- lib/intprops-internal.h
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1 /* intprops-internal.h -- properties of integer types not visible to users
2
3 Copyright (C) 2001-2024 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 /* Pacify GCC 13.2 in some calls to _GL_EXPR_SIGNED. */
24 #if defined __GNUC__ && 4 < __GNUC__ + (3 <= __GNUC_MINOR__)
25 #pragma GCC diagnostic ignored "-Wtype-limits"
26 #endif
27
28 /* Return a value with the common real type of E and V and the value of V.
29 Do not evaluate E. */
30 #define _GL_INT_CONVERT(e, v) ((1 ? 0 : (e)) + (v))
31
32 /* Act like _GL_INT_CONVERT (E, -V) but work around a bug in IRIX 6.5 cc; see
33 <https://lists.gnu.org/r/bug-gnulib/2011-05/msg00406.html>. */
34 #define _GL_INT_NEGATE_CONVERT(e, v) ((1 ? 0 : (e)) - (v))
35
36 /* The extra casts in the following macros work around compiler bugs,
37 e.g., in Cray C 5.0.3.0. */
38
39 /* True if the real type T is signed. */
40 #define _GL_TYPE_SIGNED(t) (!((t) 0 < (t) - 1))
41
42 /* Return 1 if the real expression E, after promotion, has a
43 signed or floating type. Do not evaluate E. */
44 #define _GL_EXPR_SIGNED(e) (_GL_INT_NEGATE_CONVERT (e, 1) < 0)
45
46 /* Minimum and maximum values for integer types and expressions. */
47
48 /* The width in bits of the integer type or expression T.
49 Do not evaluate T. T must not be a bit-field expression.
50 Padding bits are not supported; this is checked at compile-time below. */
51 #define _GL_TYPE_WIDTH(t) (sizeof (t) * CHAR_BIT)
52
53 /* The maximum and minimum values for the type of the expression E,
54 after integer promotion. E is not evaluated. */
55 #define _GL_INT_MINIMUM(e) \
56 (_GL_EXPR_SIGNED (e) ? ~_GL_SIGNED_INT_MAXIMUM (e) : _GL_INT_CONVERT (e, 0))
57 #define _GL_INT_MAXIMUM(e) \
58 (_GL_EXPR_SIGNED (e) ? _GL_SIGNED_INT_MAXIMUM (e) : _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__ || (4 <= __clang_major__) || (1210 <= __IBMC__ && defined __IBM__TYPEOF__) \
76 || (0x5110 <= __SUNPRO_C && !__STDC__))
77 #define _GL_HAVE___TYPEOF__ 1
78 #else
79 #define _GL_HAVE___TYPEOF__ 0
80 #endif
81
82 /* Return 1 if the integer type or expression T might be signed. Return 0
83 if it is definitely unsigned. T must not be a bit-field expression.
84 This macro does not evaluate its argument, and expands to an
85 integer constant expression. */
86 #if _GL_HAVE___TYPEOF__
87 #define _GL_SIGNED_TYPE_OR_EXPR(t) _GL_TYPE_SIGNED (__typeof__ (t))
88 #else
89 #define _GL_SIGNED_TYPE_OR_EXPR(t) 1
90 #endif
91
92 /* Return 1 if - A would overflow in [MIN,MAX] arithmetic.
93 A should not have side effects, and A's type should be an
94 integer with minimum value MIN and maximum MAX. */
95 #define _GL_INT_NEGATE_RANGE_OVERFLOW(a, min, max) ((min) < 0 ? (a) < -(max) : 0 < (a))
96
97 /* True if __builtin_add_overflow (A, B, P) and __builtin_sub_overflow
98 (A, B, P) work when P is non-null. */
99 #ifdef __EDG__
100 /* EDG-based compilers like nvc 22.1 cannot add 64-bit signed to unsigned
101 <https://bugs.gnu.org/53256>. */
102 #define _GL_HAS_BUILTIN_ADD_OVERFLOW 0
103 #elif defined __has_builtin
104 #define _GL_HAS_BUILTIN_ADD_OVERFLOW __has_builtin (__builtin_add_overflow)
105 /* __builtin_{add,sub}_overflow exists but is not reliable in GCC 5.x and 6.x,
106 see <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98269>. */
107 #elif 7 <= __GNUC__
108 #define _GL_HAS_BUILTIN_ADD_OVERFLOW 1
109 #else
110 #define _GL_HAS_BUILTIN_ADD_OVERFLOW 0
111 #endif
112
113 /* True if __builtin_mul_overflow (A, B, P) works when P is non-null. */
114 #if defined __clang_major__ && __clang_major__ < 14
115 /* Work around Clang bug <https://bugs.llvm.org/show_bug.cgi?id=16404>. */
116 #define _GL_HAS_BUILTIN_MUL_OVERFLOW 0
117 #else
118 #define _GL_HAS_BUILTIN_MUL_OVERFLOW _GL_HAS_BUILTIN_ADD_OVERFLOW
119 #endif
120
121 /* True if __builtin_add_overflow_p (A, B, C) works, and similarly for
122 __builtin_sub_overflow_p and __builtin_mul_overflow_p. */
123 #ifdef __EDG__
124 /* In EDG-based compilers like ICC 2021.3 and earlier,
125 __builtin_add_overflow_p etc. are not treated as integral constant
126 expressions even when all arguments are. */
127 #define _GL_HAS_BUILTIN_OVERFLOW_P 0
128 #elif defined __has_builtin
129 #define _GL_HAS_BUILTIN_OVERFLOW_P __has_builtin (__builtin_mul_overflow_p)
130 #else
131 #define _GL_HAS_BUILTIN_OVERFLOW_P (7 <= __GNUC__)
132 #endif
133
134 #if (!defined _GL_STDCKDINT_H && 202311 <= __STDC_VERSION__ \
135 && !(_GL_HAS_BUILTIN_ADD_OVERFLOW && _GL_HAS_BUILTIN_MUL_OVERFLOW))
136 #include <stdckdint.h>
137 #endif
138
139 /* Store the low-order bits of A + B, A - B, A * B, respectively, into *R.
140 Return 1 if the result overflows. Arguments should not have side
141 effects and A, B and *R can be of any integer type other than char,
142 bool, a bit-precise integer type, or an enumeration type. */
143 #if _GL_HAS_BUILTIN_ADD_OVERFLOW
144 #define _GL_INT_ADD_WRAPV(a, b, r) __builtin_add_overflow (a, b, r)
145 #define _GL_INT_SUBTRACT_WRAPV(a, b, r) __builtin_sub_overflow (a, b, r)
146 #elif defined ckd_add && defined ckd_sub && !defined _GL_STDCKDINT_H
147 #define _GL_INT_ADD_WRAPV(a, b, r) ckd_add (r, +(a), +(b))
148 #define _GL_INT_SUBTRACT_WRAPV(a, b, r) ckd_sub (r, +(a), +(b))
149 #else
150 #define _GL_INT_ADD_WRAPV(a, b, r) _GL_INT_OP_WRAPV (a, b, r, +, _GL_INT_ADD_RANGE_OVERFLOW)
151 #define _GL_INT_SUBTRACT_WRAPV(a, b, r) \
152 _GL_INT_OP_WRAPV (a, b, r, -, _GL_INT_SUBTRACT_RANGE_OVERFLOW)
153 #endif
154 #if _GL_HAS_BUILTIN_MUL_OVERFLOW
155 #if ((9 < __GNUC__ + (3 <= __GNUC_MINOR__) || (__GNUC__ == 8 && 4 <= __GNUC_MINOR__)) \
156 && !defined __EDG__)
157 #define _GL_INT_MULTIPLY_WRAPV(a, b, r) __builtin_mul_overflow (a, b, r)
158 #else
159 // Work around GCC bug 91450.
160 #define _GL_INT_MULTIPLY_WRAPV(a, b, r) \
161 ((!_GL_SIGNED_TYPE_OR_EXPR (*(r)) && _GL_EXPR_SIGNED (a) && _GL_EXPR_SIGNED (b) \
162 && _GL_INT_MULTIPLY_RANGE_OVERFLOW (a, b, (__typeof__ (*(r))) 0, (__typeof__ (*(r))) -1)) \
163 ? ((void) __builtin_mul_overflow (a, b, r), 1) \
164 : __builtin_mul_overflow (a, b, r))
165 #endif
166 #elif defined ckd_mul && !defined _GL_STDCKDINT_H
167 #define _GL_INT_MULTIPLY_WRAPV(a, b, r) ckd_mul (r, +(a), +(b))
168 #else
169 #define _GL_INT_MULTIPLY_WRAPV(a, b, r) \
170 _GL_INT_OP_WRAPV (a, b, r, *, _GL_INT_MULTIPLY_RANGE_OVERFLOW)
171 #endif
172
173 /* Nonzero if this compiler has GCC bug 68193 or Clang bug 25390. See:
174 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68193
175 https://llvm.org/bugs/show_bug.cgi?id=25390
176 For now, assume GCC < 14 and all Clang versions generate bogus
177 warnings for _Generic. This matters only for compilers that
178 lack relevant builtins. */
179 #if (__GNUC__ && __GNUC__ < 14) || defined __clang__
180 #define _GL__GENERIC_BOGUS 1
181 #else
182 #define _GL__GENERIC_BOGUS 0
183 #endif
184
185 /* Store the low-order bits of A <op> B into *R, where OP specifies
186 the operation and OVERFLOW the overflow predicate. Return 1 if the
187 result overflows. Arguments should not have side effects,
188 and A, B and *R can be of any integer type other than char, bool, a
189 bit-precise integer type, or an enumeration type. */
190 #if 201112 <= __STDC_VERSION__ && !_GL__GENERIC_BOGUS
191 #define _GL_INT_OP_WRAPV(a, b, r, op, overflow) \
192 (_Generic (*(r), \
193 signed char: _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, signed char, \
194 SCHAR_MIN, SCHAR_MAX), \
195 unsigned char: _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, unsigned char, 0, \
196 UCHAR_MAX), \
197 short int: _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, short int, SHRT_MIN, \
198 SHRT_MAX), \
199 unsigned short int: _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
200 unsigned short int, 0, USHRT_MAX), \
201 int: _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, int, INT_MIN, INT_MAX), \
202 unsigned int: _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, unsigned int, 0, \
203 UINT_MAX), \
204 long int: _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, long int, LONG_MIN, \
205 LONG_MAX), \
206 unsigned long int: _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
207 unsigned long int, 0, ULONG_MAX), \
208 long long int: _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
209 long long int, LLONG_MIN, LLONG_MAX), \
210 unsigned long long int: _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
211 unsigned long long int, 0, ULLONG_MAX)))
212 #else
213 /* Store the low-order bits of A <op> B into *R, where OP specifies
214 the operation and OVERFLOW the overflow predicate. If *R is
215 signed, its type is ST with bounds SMIN..SMAX; otherwise its type
216 is UT with bounds U..UMAX. ST and UT are narrower than int.
217 Return 1 if the result overflows. Arguments should not have side
218 effects, and A, B and *R can be of any integer type other than
219 char, bool, a bit-precise integer type, or an enumeration type. */
220 #if _GL_HAVE___TYPEOF__
221 #define _GL_INT_OP_WRAPV_SMALLISH(a, b, r, op, overflow, st, smin, smax, ut, umax) \
222 (_GL_TYPE_SIGNED (__typeof__ (*(r))) \
223 ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, st, smin, smax) \
224 : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, ut, 0, umax))
225 #else
226 #define _GL_INT_OP_WRAPV_SMALLISH(a, b, r, op, overflow, st, smin, smax, ut, umax) \
227 (overflow (a, b, smin, smax) \
228 ? (overflow (a, b, 0, umax) \
229 ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, unsigned, st), 1) \
230 : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, unsigned, st)) < 0) \
231 : (overflow (a, b, 0, umax) \
232 ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, unsigned, st)) >= 0 \
233 : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, unsigned, st), 0)))
234 #endif
235
236 #define _GL_INT_OP_WRAPV(a, b, r, op, overflow) \
237 (sizeof *(r) == sizeof (signed char) \
238 ? _GL_INT_OP_WRAPV_SMALLISH (a, b, r, op, overflow, signed char, SCHAR_MIN, SCHAR_MAX, \
239 unsigned char, UCHAR_MAX) \
240 : sizeof *(r) == sizeof (short int) \
241 ? _GL_INT_OP_WRAPV_SMALLISH (a, b, r, op, overflow, short int, SHRT_MIN, SHRT_MAX, \
242 unsigned short int, USHRT_MAX) \
243 : sizeof *(r) == sizeof (int) \
244 ? (_GL_EXPR_SIGNED (*(r)) \
245 ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, int, INT_MIN, INT_MAX) \
246 : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, unsigned int, 0, \
247 UINT_MAX)) \
248 : _GL_INT_OP_WRAPV_LONGISH (a, b, r, op, overflow))
249 #ifdef LLONG_MAX
250 #define _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow) \
251 (sizeof *(r) == sizeof (long int) \
252 ? (_GL_EXPR_SIGNED (*(r)) ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
253 long int, LONG_MIN, LONG_MAX) \
254 : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
255 unsigned long int, 0, ULONG_MAX)) \
256 : (_GL_EXPR_SIGNED (*(r)) \
257 ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, long long int, \
258 LLONG_MIN, LLONG_MAX) \
259 : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
260 unsigned long long int, 0, ULLONG_MAX)))
261 #else
262 #define _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow) \
263 (_GL_EXPR_SIGNED (*(r)) ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, long int, \
264 LONG_MIN, LONG_MAX) \
265 : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
266 unsigned long int, 0, ULONG_MAX))
267 #endif
268 #endif
269
270 /* Store the low-order bits of A <op> B into *R, where the operation
271 is given by OP. Use the unsigned type UT for calculation to avoid
272 overflow problems. *R's type is T, with extrema TMIN and TMAX.
273 T can be any signed integer type other than char, bool, a
274 bit-precise integer type, or an enumeration type.
275 Return 1 if the result overflows. */
276 #define _GL_INT_OP_CALC(a, b, r, op, overflow, ut, t, tmin, tmax) \
277 (overflow (a, b, tmin, tmax) ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t), 1) \
278 : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t), 0))
279
280 /* Return 1 if the integer expressions A - B and -A would overflow,
281 respectively. Arguments should not have side effects,
282 and can be any signed integer type other than char, bool, a
283 bit-precise integer type, or an enumeration type.
284 These macros are tuned for their last input argument being a constant. */
285
286 #if _GL_HAS_BUILTIN_OVERFLOW_P
287 #define _GL_INT_NEGATE_OVERFLOW(a) __builtin_sub_overflow_p (0, a, (__typeof__ (-(a))) 0)
288 #else
289 #define _GL_INT_NEGATE_OVERFLOW(a) \
290 _GL_INT_NEGATE_RANGE_OVERFLOW (a, _GL_INT_MINIMUM (a), _GL_INT_MAXIMUM (a))
291 #endif
292
293 /* Return the low-order bits of A <op> B, where the operation is given
294 by OP. Use the unsigned type UT for calculation to avoid undefined
295 behavior on signed integer overflow, and convert the result to type T.
296 UT is at least as wide as T and is no narrower than unsigned int,
297 T is two's complement, and there is no padding or trap representations.
298 Assume that converting UT to T yields the low-order bits, as is
299 done in all known two's-complement C compilers. E.g., see:
300 https://gcc.gnu.org/onlinedocs/gcc/Integers-implementation.html
301
302 According to the C standard, converting UT to T yields an
303 implementation-defined result or signal for values outside T's
304 range. However, code that works around this theoretical problem
305 runs afoul of a compiler bug in Oracle Studio 12.3 x86. See:
306 https://lists.gnu.org/r/bug-gnulib/2017-04/msg00049.html
307 As the compiler bug is real, don't try to work around the
308 theoretical problem. */
309
310 #define _GL_INT_OP_WRAPV_VIA_UNSIGNED(a, b, op, ut, t) ((t) ((ut) (a) op (ut) (b)))
311
312 /* Return true if the numeric values A + B, A - B, A * B fall outside
313 the range TMIN..TMAX. Arguments should not have side effects
314 and can be any integer type other than char, bool,
315 a bit-precise integer type, or an enumeration type.
316 TMIN should be signed and nonpositive.
317 TMAX should be positive, and should be signed unless TMIN is zero. */
318 #define _GL_INT_ADD_RANGE_OVERFLOW(a, b, tmin, tmax) \
319 ((b) < 0 ? (((tmin) ? ((_GL_EXPR_SIGNED (_GL_INT_CONVERT (a, (tmin) - (b))) || (b) < (tmin)) \
320 && (a) < (tmin) - (b)) \
321 : (a) <= -1 - (b)) \
322 || ((_GL_EXPR_SIGNED (a) ? 0 <= (a) : (tmax) < (a)) && (tmax) < (a) + (b))) \
323 : (a) < 0 \
324 ? (((tmin) ? ((_GL_EXPR_SIGNED (_GL_INT_CONVERT (b, (tmin) - (a))) || (a) < (tmin)) \
325 && (b) < (tmin) - (a)) \
326 : (b) <= -1 - (a)) \
327 || ((_GL_EXPR_SIGNED (_GL_INT_CONVERT (a, b)) || (tmax) < (b)) && (tmax) < (a) + (b))) \
328 : (tmax) < (b) || (tmax) - (b) < (a))
329 #define _GL_INT_SUBTRACT_RANGE_OVERFLOW(a, b, tmin, tmax) \
330 (((a) < 0) == ((b) < 0) \
331 ? ((a) < (b) ? !(tmin) || -1 - (tmin) < (b) - (a) - 1 : (tmax) < (a) - (b)) \
332 : (a) < 0 ? ((!_GL_EXPR_SIGNED (_GL_INT_CONVERT ((a) - (tmin), b)) && (a) - (tmin) < 0) \
333 || (a) - (tmin) < (b)) \
334 : ((!(_GL_EXPR_SIGNED (_GL_INT_CONVERT (tmax, b)) \
335 && _GL_EXPR_SIGNED (_GL_INT_CONVERT ((tmax) + (b), a))) \
336 && (tmax) <= -1 - (b)) \
337 || (tmax) + (b) < (a)))
338 #define _GL_INT_MULTIPLY_RANGE_OVERFLOW(a, b, tmin, tmax) \
339 ((b) < 0 ? ((a) < 0 ? (_GL_EXPR_SIGNED (_GL_INT_CONVERT (tmax, b)) \
340 ? (a) < (tmax) / (b) \
341 : ((_GL_INT_NEGATE_OVERFLOW (b) \
342 ? _GL_INT_CONVERT (b, tmax) >> (_GL_TYPE_WIDTH (+(b)) - 1) \
343 : (tmax) / -(b)) \
344 <= -1 - (a))) \
345 : _GL_INT_NEGATE_OVERFLOW (_GL_INT_CONVERT (b, tmin)) && (b) == -1 \
346 ? (_GL_EXPR_SIGNED (a) ? 0 < (a) + (tmin) : 0 < (a) && -1 - (tmin) < (a) - 1) \
347 : (tmin) / (b) < (a)) \
348 : (b) == 0 \
349 ? 0 \
350 : ((a) < 0 ? (_GL_INT_NEGATE_OVERFLOW (_GL_INT_CONVERT (a, tmin)) && (a) == -1 \
351 ? (_GL_EXPR_SIGNED (b) ? 0 < (b) + (tmin) : -1 - (tmin) < (b) - 1) \
352 : (tmin) / (a) < (b)) \
353 : (tmax) / (b) < (a)))
354
355 #endif
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