/* intprops.h -- properties of integer types
- Copyright (C) 2001-2016 Free Software Foundation, Inc.
+ Copyright (C) 2001-2018 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Paul Eggert. */
#define _GL_INTPROPS_H
#include <limits.h>
-#include <verify.h>
/* Return a value with the common real type of E and V and the value of V. */
#define _GL_INT_CONVERT(e, v) (0 * (e) + (v))
/* Act like _GL_INT_CONVERT (E, -V) but work around a bug in IRIX 6.5 cc; see
- <http://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00406.html>. */
+ <https://lists.gnu.org/r/bug-gnulib/2011-05/msg00406.html>. */
#define _GL_INT_NEGATE_CONVERT(e, v) (0 * (e) - (v))
/* The extra casts in the following macros work around compiler bugs,
/* Minimum and maximum values for integer types and expressions. */
+/* The width in bits of the integer type or expression T.
+ Padding bits are not supported; this is checked at compile-time below. */
+#define TYPE_WIDTH(t) (sizeof (t) * CHAR_BIT)
+
/* The maximum and minimum values for the integer type T. */
#define TYPE_MINIMUM(t) ((t) ~ TYPE_MAXIMUM (t))
#define TYPE_MAXIMUM(t) \
((t) (! TYPE_SIGNED (t) \
? (t) -1 \
- : ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))
+ : ((((t) 1 << (TYPE_WIDTH (t) - 2)) - 1) * 2 + 1)))
/* The maximum and minimum values for the type of the expression E,
after integer promotion. E should not have side effects. */
? _GL_SIGNED_INT_MAXIMUM (e) \
: _GL_INT_NEGATE_CONVERT (e, 1))
#define _GL_SIGNED_INT_MAXIMUM(e) \
- (((_GL_INT_CONVERT (e, 1) << (sizeof ((e) + 0) * CHAR_BIT - 2)) - 1) * 2 + 1)
+ (((_GL_INT_CONVERT (e, 1) << (TYPE_WIDTH ((e) + 0) - 2)) - 1) * 2 + 1)
+
+/* Work around OpenVMS incompatibility with C99. */
+#if !defined LLONG_MAX && defined __INT64_MAX
+# define LLONG_MAX __INT64_MAX
+# define LLONG_MIN __INT64_MIN
+#endif
/* This include file assumes that signed types are two's complement without
padding bits; the above macros have undefined behavior otherwise.
If this is a problem for you, please let us know how to fix it for your host.
- As a sanity check, test the assumption for some signed types that
- <limits.h> bounds. */
-verify (TYPE_MINIMUM (signed char) == SCHAR_MIN);
-verify (TYPE_MAXIMUM (signed char) == SCHAR_MAX);
-verify (TYPE_MINIMUM (short int) == SHRT_MIN);
-verify (TYPE_MAXIMUM (short int) == SHRT_MAX);
-verify (TYPE_MINIMUM (int) == INT_MIN);
-verify (TYPE_MAXIMUM (int) == INT_MAX);
-verify (TYPE_MINIMUM (long int) == LONG_MIN);
-verify (TYPE_MAXIMUM (long int) == LONG_MAX);
-#ifdef LLONG_MAX
-verify (TYPE_MINIMUM (long long int) == LLONG_MIN);
-verify (TYPE_MAXIMUM (long long int) == LLONG_MAX);
-#endif
+ This assumption is tested by the intprops-tests module. */
/* Does the __typeof__ keyword work? This could be done by
'configure', but for now it's easier to do it by hand. */
-#if (2 <= __GNUC__ || defined __IBM__TYPEOF__ \
+#if (2 <= __GNUC__ \
+ || (1210 <= __IBMC__ && defined __IBM__TYPEOF__) \
|| (0x5110 <= __SUNPRO_C && !__STDC__))
# define _GL_HAVE___TYPEOF__ 1
#else
signed, this macro may overestimate the true bound by one byte when
applied to unsigned types of size 2, 4, 16, ... bytes. */
#define INT_STRLEN_BOUND(t) \
- (INT_BITS_STRLEN_BOUND (sizeof (t) * CHAR_BIT \
- - _GL_SIGNED_TYPE_OR_EXPR (t)) \
+ (INT_BITS_STRLEN_BOUND (TYPE_WIDTH (t) - _GL_SIGNED_TYPE_OR_EXPR (t)) \
+ _GL_SIGNED_TYPE_OR_EXPR (t))
/* Bound on buffer size needed to represent an integer type or expression T,
/* Return 1 if A * B would overflow in [MIN,MAX] arithmetic.
See above for restrictions. Avoid && and || as they tickle
bugs in Sun C 5.11 2010/08/13 and other compilers; see
- <http://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00401.html>. */
+ <https://lists.gnu.org/r/bug-gnulib/2011-05/msg00401.html>. */
#define INT_MULTIPLY_RANGE_OVERFLOW(a, b, min, max) \
((b) < 0 \
? ((a) < 0 \
? (a) < (min) >> (b) \
: (max) >> (b) < (a))
+/* True if __builtin_add_overflow (A, B, P) works when P is non-null. */
+#if 5 <= __GNUC__ && !defined __ICC
+# define _GL_HAS_BUILTIN_OVERFLOW 1
+#else
+# define _GL_HAS_BUILTIN_OVERFLOW 0
+#endif
+
+/* True if __builtin_add_overflow_p (A, B, C) works. */
+#define _GL_HAS_BUILTIN_OVERFLOW_P (7 <= __GNUC__)
/* The _GL*_OVERFLOW macros have the same restrictions as the
*_RANGE_OVERFLOW macros, except that they do not assume that operands
(e.g., A and B) have the same type as MIN and MAX. Instead, they assume
that the result (e.g., A + B) has that type. */
-#define _GL_ADD_OVERFLOW(a, b, min, max) \
- ((min) < 0 ? INT_ADD_RANGE_OVERFLOW (a, b, min, max) \
- : (a) < 0 ? (b) <= (a) + (b) \
- : (b) < 0 ? (a) <= (a) + (b) \
- : (a) + (b) < (b))
-#define _GL_SUBTRACT_OVERFLOW(a, b, min, max) \
- ((min) < 0 ? INT_SUBTRACT_RANGE_OVERFLOW (a, b, min, max) \
- : (a) < 0 ? 1 \
- : (b) < 0 ? (a) - (b) <= (a) \
- : (a) < (b))
-#define _GL_MULTIPLY_OVERFLOW(a, b, min, max) \
- (((min) == 0 && (((a) < 0 && 0 < (b)) || ((b) < 0 && 0 < (a)))) \
- || INT_MULTIPLY_RANGE_OVERFLOW (a, b, min, max))
+#if _GL_HAS_BUILTIN_OVERFLOW_P
+# define _GL_ADD_OVERFLOW(a, b, min, max) \
+ __builtin_add_overflow_p (a, b, (__typeof__ ((a) + (b))) 0)
+# define _GL_SUBTRACT_OVERFLOW(a, b, min, max) \
+ __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0)
+# define _GL_MULTIPLY_OVERFLOW(a, b, min, max) \
+ __builtin_mul_overflow_p (a, b, (__typeof__ ((a) * (b))) 0)
+#else
+# define _GL_ADD_OVERFLOW(a, b, min, max) \
+ ((min) < 0 ? INT_ADD_RANGE_OVERFLOW (a, b, min, max) \
+ : (a) < 0 ? (b) <= (a) + (b) \
+ : (b) < 0 ? (a) <= (a) + (b) \
+ : (a) + (b) < (b))
+# define _GL_SUBTRACT_OVERFLOW(a, b, min, max) \
+ ((min) < 0 ? INT_SUBTRACT_RANGE_OVERFLOW (a, b, min, max) \
+ : (a) < 0 ? 1 \
+ : (b) < 0 ? (a) - (b) <= (a) \
+ : (a) < (b))
+# define _GL_MULTIPLY_OVERFLOW(a, b, min, max) \
+ (((min) == 0 && (((a) < 0 && 0 < (b)) || ((b) < 0 && 0 < (a)))) \
+ || INT_MULTIPLY_RANGE_OVERFLOW (a, b, min, max))
+#endif
#define _GL_DIVIDE_OVERFLOW(a, b, min, max) \
((min) < 0 ? (b) == _GL_INT_NEGATE_CONVERT (min, 1) && (a) < - (max) \
: (a) < 0 ? (b) <= (a) + (b) - 1 \
_GL_BINARY_OP_OVERFLOW (a, b, _GL_ADD_OVERFLOW)
#define INT_SUBTRACT_OVERFLOW(a, b) \
_GL_BINARY_OP_OVERFLOW (a, b, _GL_SUBTRACT_OVERFLOW)
-#define INT_NEGATE_OVERFLOW(a) \
- INT_NEGATE_RANGE_OVERFLOW (a, _GL_INT_MINIMUM (a), _GL_INT_MAXIMUM (a))
+#if _GL_HAS_BUILTIN_OVERFLOW_P
+# define INT_NEGATE_OVERFLOW(a) INT_SUBTRACT_OVERFLOW (0, a)
+#else
+# define INT_NEGATE_OVERFLOW(a) \
+ INT_NEGATE_RANGE_OVERFLOW (a, _GL_INT_MINIMUM (a), _GL_INT_MAXIMUM (a))
+#endif
#define INT_MULTIPLY_OVERFLOW(a, b) \
_GL_BINARY_OP_OVERFLOW (a, b, _GL_MULTIPLY_OVERFLOW)
#define INT_DIVIDE_OVERFLOW(a, b) \
_GL_INT_MINIMUM (0 * (b) + (a)), \
_GL_INT_MAXIMUM (0 * (b) + (a)))
-/* Compute A + B, A - B, A * B, respectively, storing the result into *R.
+/* Store the low-order bits of A + B, A - B, A * B, respectively, into *R.
Return 1 if the result overflows. See above for restrictions. */
#define INT_ADD_WRAPV(a, b, r) \
_GL_INT_OP_WRAPV (a, b, r, +, __builtin_add_overflow, INT_ADD_OVERFLOW)
#define INT_MULTIPLY_WRAPV(a, b, r) \
_GL_INT_OP_WRAPV (a, b, r, *, __builtin_mul_overflow, INT_MULTIPLY_OVERFLOW)
-#ifndef __has_builtin
-# define __has_builtin(x) 0
-#endif
-
/* Nonzero if this compiler has GCC bug 68193 or Clang bug 25390. See:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68193
https://llvm.org/bugs/show_bug.cgi?id=25390
# define _GL__GENERIC_BOGUS 0
#endif
-/* Store A <op> B into *R, where OP specifies the operation.
- BUILTIN is the builtin operation, and OVERFLOW the overflow predicate.
- See above for restrictions. */
-#if 5 <= __GNUC__ || __has_builtin (__builtin_add_overflow)
+/* Store the low-order bits of A <op> B into *R, where OP specifies
+ the operation. BUILTIN is the builtin operation, and OVERFLOW the
+ overflow predicate. Return 1 if the result overflows. See above
+ for restrictions. */
+#if _GL_HAS_BUILTIN_OVERFLOW
# define _GL_INT_OP_WRAPV(a, b, r, op, builtin, overflow) builtin (a, b, r)
#elif 201112 <= __STDC_VERSION__ && !_GL__GENERIC_BOGUS
# define _GL_INT_OP_WRAPV(a, b, r, op, builtin, overflow) \
(_Generic \
(*(r), \
signed char: \
- _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned char, \
+ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
signed char, SCHAR_MIN, SCHAR_MAX), \
short int: \
- _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned short int, \
+ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
short int, SHRT_MIN, SHRT_MAX), \
int: \
_GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
#else
# define _GL_INT_OP_WRAPV(a, b, r, op, builtin, overflow) \
(sizeof *(r) == sizeof (signed char) \
- ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned char, \
+ ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
signed char, SCHAR_MIN, SCHAR_MAX) \
: sizeof *(r) == sizeof (short int) \
- ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned short int, \
+ ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
short int, SHRT_MIN, SHRT_MAX) \
: sizeof *(r) == sizeof (int) \
? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
# else
# define _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow) \
_GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
- long int, LONG_MIN, LONG_MAX))
+ long int, LONG_MIN, LONG_MAX)
# endif
#endif
/* Store the low-order bits of A <op> B into *R, where the operation
is given by OP. Use the unsigned type UT for calculation to avoid
- overflow problems. *R's type is T, with extremal values TMIN and
- TMAX. T must be a signed integer type. */
+ overflow problems. *R's type is T, with extrema TMIN and TMAX.
+ T must be a signed integer type. Return 1 if the result overflows. */
#define _GL_INT_OP_CALC(a, b, r, op, overflow, ut, t, tmin, tmax) \
(sizeof ((a) op (b)) < sizeof (t) \
? _GL_INT_OP_CALC1 ((t) (a), (t) (b), r, op, overflow, ut, t, tmin, tmax) \
((overflow (a, b) \
|| (EXPR_SIGNED ((a) op (b)) && ((a) op (b)) < (tmin)) \
|| (tmax) < ((a) op (b))) \
- ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t, tmin, tmax), 1) \
- : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t, tmin, tmax), 0))
-
-/* Return A <op> B, where the operation is given by OP. Use the
- unsigned type UT for calculation to avoid overflow problems.
- Convert the result to type T without overflow by subtracting TMIN
- from large values before converting, and adding it afterwards.
- Compilers can optimize all the operations except OP. */
-#define _GL_INT_OP_WRAPV_VIA_UNSIGNED(a, b, op, ut, t, tmin, tmax) \
- (((ut) (a) op (ut) (b)) <= (tmax) \
- ? (t) ((ut) (a) op (ut) (b)) \
- : ((t) (((ut) (a) op (ut) (b)) - (tmin)) + (tmin)))
+ ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t), 1) \
+ : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t), 0))
+
+/* Return the low-order bits of A <op> B, where the operation is given
+ by OP. Use the unsigned type UT for calculation to avoid undefined
+ behavior on signed integer overflow, and convert the result to type T.
+ UT is at least as wide as T and is no narrower than unsigned int,
+ T is two's complement, and there is no padding or trap representations.
+ Assume that converting UT to T yields the low-order bits, as is
+ done in all known two's-complement C compilers. E.g., see:
+ https://gcc.gnu.org/onlinedocs/gcc/Integers-implementation.html
+
+ According to the C standard, converting UT to T yields an
+ implementation-defined result or signal for values outside T's
+ range. However, code that works around this theoretical problem
+ runs afoul of a compiler bug in Oracle Studio 12.3 x86. See:
+ https://lists.gnu.org/r/bug-gnulib/2017-04/msg00049.html
+ As the compiler bug is real, don't try to work around the
+ theoretical problem. */
+
+#define _GL_INT_OP_WRAPV_VIA_UNSIGNED(a, b, op, ut, t) \
+ ((t) ((ut) (a) op (ut) (b)))
#endif /* _GL_INTPROPS_H */
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