diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/intprops.h | 214 |
1 files changed, 169 insertions, 45 deletions
diff --git a/include/intprops.h b/include/intprops.h index 140f6d2a4b..bc7e950a0e 100644 --- a/include/intprops.h +++ b/include/intprops.h @@ -111,8 +111,8 @@ Subtract 1 for the sign bit if T is signed, and then add 1 more for a minus sign if needed. - Because _GL_SIGNED_TYPE_OR_EXPR sometimes returns 0 when its argument is - signed, this macro may overestimate the true bound by one byte when + Because _GL_SIGNED_TYPE_OR_EXPR sometimes returns 1 when its argument is + unsigned, 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 (TYPE_WIDTH (t) - _GL_SIGNED_TYPE_OR_EXPR (t)) \ @@ -220,14 +220,26 @@ ? (a) < (min) >> (b) \ : (max) >> (b) < (a)) -/* True if __builtin_add_overflow (A, B, P) works when P is non-null. */ +/* True if __builtin_add_overflow (A, B, P) and __builtin_sub_overflow + (A, B, P) work when P is non-null. */ #if 5 <= __GNUC__ && !defined __ICC -# define _GL_HAS_BUILTIN_OVERFLOW 1 +# define _GL_HAS_BUILTIN_ADD_OVERFLOW 1 +#elif defined __has_builtin +# define _GL_HAS_BUILTIN_ADD_OVERFLOW __has_builtin (__builtin_add_overflow) #else -# define _GL_HAS_BUILTIN_OVERFLOW 0 +# define _GL_HAS_BUILTIN_ADD_OVERFLOW 0 #endif -/* True if __builtin_add_overflow_p (A, B, C) works. */ +/* True if __builtin_mul_overflow (A, B, P) works when P is non-null. */ +#ifdef __clang__ +/* Work around Clang bug <https://bugs.llvm.org/show_bug.cgi?id=16404>. */ +# define _GL_HAS_BUILTIN_MUL_OVERFLOW 0 +#else +# define _GL_HAS_BUILTIN_MUL_OVERFLOW _GL_HAS_BUILTIN_ADD_OVERFLOW +#endif + +/* True if __builtin_add_overflow_p (A, B, C) works, and similarly for + __builtin_mul_overflow_p and __builtin_mul_overflow_p. */ #define _GL_HAS_BUILTIN_OVERFLOW_P (7 <= __GNUC__) /* The _GL*_OVERFLOW macros have the same restrictions as the @@ -281,7 +293,9 @@ The INT_<op>_OVERFLOW macros return 1 if the corresponding C operators might not yield numerically correct answers due to arithmetic overflow. - The INT_<op>_WRAPV macros also store the low-order bits of the answer. + The INT_<op>_WRAPV macros compute the low-order bits of the sum, + difference, and product of two C integers, and return 1 if these + low-order bits are not numerically correct. These macros work correctly on all known practical hosts, and do not rely on undefined behavior due to signed arithmetic overflow. @@ -309,9 +323,11 @@ arguments should not have side effects. The WRAPV macros are not constant expressions. They support only - +, binary -, and *. The result type must be signed. + +, binary -, and *. Because the WRAPV macros convert the result, + they report overflow in different circumstances than the OVERFLOW + macros do. - These macros are tuned for their last argument being a constant. + These macros are tuned for their last input argument being a constant. Return 1 if the integer expressions A * B, A - B, -A, A * B, A / B, A % B, and A << B would overflow, respectively. */ @@ -347,19 +363,33 @@ /* 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_SUBTRACT_WRAPV(a, b, r) \ - _GL_INT_OP_WRAPV (a, b, r, -, __builtin_sub_overflow, INT_SUBTRACT_OVERFLOW) -#define INT_MULTIPLY_WRAPV(a, b, r) \ - _GL_INT_OP_WRAPV (a, b, r, *, __builtin_mul_overflow, INT_MULTIPLY_OVERFLOW) +#if _GL_HAS_BUILTIN_ADD_OVERFLOW +# define INT_ADD_WRAPV(a, b, r) __builtin_add_overflow (a, b, r) +# define INT_SUBTRACT_WRAPV(a, b, r) __builtin_sub_overflow (a, b, r) +#else +# define INT_ADD_WRAPV(a, b, r) \ + _GL_INT_OP_WRAPV (a, b, r, +, _GL_INT_ADD_RANGE_OVERFLOW) +# define INT_SUBTRACT_WRAPV(a, b, r) \ + _GL_INT_OP_WRAPV (a, b, r, -, _GL_INT_SUBTRACT_RANGE_OVERFLOW) +#endif +#if _GL_HAS_BUILTIN_MUL_OVERFLOW +/* Work around GCC bug 91450. */ +# define INT_MULTIPLY_WRAPV(a, b, r) \ + ((!_GL_SIGNED_TYPE_OR_EXPR (*(r)) && EXPR_SIGNED (a) && EXPR_SIGNED (b) \ + && _GL_INT_MULTIPLY_RANGE_OVERFLOW (a, b, 0, (__typeof__ (*(r))) -1)) \ + ? ((void) __builtin_mul_overflow (a, b, r), 1) \ + : __builtin_mul_overflow (a, b, r)) +#else +# define INT_MULTIPLY_WRAPV(a, b, r) \ + _GL_INT_OP_WRAPV (a, b, r, *, _GL_INT_MULTIPLY_RANGE_OVERFLOW) +#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 For now, assume all versions of GCC-like compilers generate bogus - warnings for _Generic. This matters only for older compilers that - lack __builtin_add_overflow. */ + warnings for _Generic. This matters only for compilers that + lack relevant builtins. */ #if __GNUC__ # define _GL__GENERIC_BOGUS 1 #else @@ -367,53 +397,100 @@ #endif /* 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) \ + the operation and OVERFLOW the overflow predicate. Return 1 if the + result overflows. See above for restrictions. */ +#if 201112 <= __STDC_VERSION__ && !_GL__GENERIC_BOGUS +# define _GL_INT_OP_WRAPV(a, b, r, op, overflow) \ (_Generic \ (*(r), \ signed char: \ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ signed char, SCHAR_MIN, SCHAR_MAX), \ + unsigned char: \ + _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ + unsigned char, 0, UCHAR_MAX), \ short int: \ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ short int, SHRT_MIN, SHRT_MAX), \ + unsigned short int: \ + _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ + unsigned short int, 0, USHRT_MAX), \ int: \ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ int, INT_MIN, INT_MAX), \ + unsigned int: \ + _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ + unsigned int, 0, UINT_MAX), \ long int: \ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \ long int, LONG_MIN, LONG_MAX), \ + unsigned long int: \ + _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \ + unsigned long int, 0, ULONG_MAX), \ long long int: \ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \ - long long int, LLONG_MIN, LLONG_MAX))) + long long int, LLONG_MIN, LLONG_MAX), \ + unsigned long long int: \ + _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \ + unsigned long long int, 0, ULLONG_MAX))) #else -# define _GL_INT_OP_WRAPV(a, b, r, op, builtin, overflow) \ +/* Store the low-order bits of A <op> B into *R, where OP specifies + the operation and OVERFLOW the overflow predicate. If *R is + signed, its type is ST with bounds SMIN..SMAX; otherwise its type + is UT with bounds U..UMAX. ST and UT are narrower than int. + Return 1 if the result overflows. See above for restrictions. */ +# if _GL_HAVE___TYPEOF__ +# define _GL_INT_OP_WRAPV_SMALLISH(a,b,r,op,overflow,st,smin,smax,ut,umax) \ + (TYPE_SIGNED (__typeof__ (*(r))) \ + ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, st, smin, smax) \ + : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, ut, 0, umax)) +# else +# define _GL_INT_OP_WRAPV_SMALLISH(a,b,r,op,overflow,st,smin,smax,ut,umax) \ + (overflow (a, b, smin, smax) \ + ? (overflow (a, b, 0, umax) \ + ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st), 1) \ + : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st)) < 0) \ + : (overflow (a, b, 0, umax) \ + ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st)) >= 0 \ + : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st), 0))) +# endif + +# define _GL_INT_OP_WRAPV(a, b, r, op, overflow) \ (sizeof *(r) == sizeof (signed char) \ - ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ - signed char, SCHAR_MIN, SCHAR_MAX) \ + ? _GL_INT_OP_WRAPV_SMALLISH (a, b, r, op, overflow, \ + signed char, SCHAR_MIN, SCHAR_MAX, \ + unsigned char, UCHAR_MAX) \ : sizeof *(r) == sizeof (short int) \ - ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ - short int, SHRT_MIN, SHRT_MAX) \ + ? _GL_INT_OP_WRAPV_SMALLISH (a, b, r, op, overflow, \ + short int, SHRT_MIN, SHRT_MAX, \ + unsigned short int, USHRT_MAX) \ : sizeof *(r) == sizeof (int) \ - ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ - int, INT_MIN, INT_MAX) \ + ? (EXPR_SIGNED (*(r)) \ + ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ + int, INT_MIN, INT_MAX) \ + : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ + unsigned int, 0, UINT_MAX)) \ : _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow)) # ifdef LLONG_MAX # define _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow) \ (sizeof *(r) == sizeof (long int) \ - ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \ - long int, LONG_MIN, LONG_MAX) \ - : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \ - long long int, LLONG_MIN, LLONG_MAX)) + ? (EXPR_SIGNED (*(r)) \ + ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \ + long int, LONG_MIN, LONG_MAX) \ + : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \ + unsigned long int, 0, ULONG_MAX)) \ + : (EXPR_SIGNED (*(r)) \ + ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \ + long long int, LLONG_MIN, LLONG_MAX) \ + : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \ + unsigned long long int, 0, ULLONG_MAX))) # 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) + (EXPR_SIGNED (*(r)) \ + ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \ + long int, LONG_MIN, LONG_MAX) \ + : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \ + unsigned long int, 0, ULONG_MAX)) # endif #endif @@ -422,13 +499,7 @@ 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) \ - : _GL_INT_OP_CALC1 (a, b, r, op, overflow, ut, t, tmin, tmax)) -#define _GL_INT_OP_CALC1(a, b, r, op, overflow, ut, t, tmin, tmax) \ - ((overflow (a, b) \ - || (EXPR_SIGNED ((a) op (b)) && ((a) op (b)) < (tmin)) \ - || (tmax) < ((a) op (b))) \ + (overflow (a, b, tmin, tmax) \ ? (*(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)) @@ -452,4 +523,57 @@ #define _GL_INT_OP_WRAPV_VIA_UNSIGNED(a, b, op, ut, t) \ ((t) ((ut) (a) op (ut) (b))) +/* Return true if the numeric values A + B, A - B, A * B fall outside + the range TMIN..TMAX. Arguments should be integer expressions + without side effects. TMIN should be signed and nonpositive. + TMAX should be positive, and should be signed unless TMIN is zero. */ +#define _GL_INT_ADD_RANGE_OVERFLOW(a, b, tmin, tmax) \ + ((b) < 0 \ + ? (((tmin) \ + ? ((EXPR_SIGNED (_GL_INT_CONVERT (a, (tmin) - (b))) || (b) < (tmin)) \ + && (a) < (tmin) - (b)) \ + : (a) <= -1 - (b)) \ + || ((EXPR_SIGNED (a) ? 0 <= (a) : (tmax) < (a)) && (tmax) < (a) + (b))) \ + : (a) < 0 \ + ? (((tmin) \ + ? ((EXPR_SIGNED (_GL_INT_CONVERT (b, (tmin) - (a))) || (a) < (tmin)) \ + && (b) < (tmin) - (a)) \ + : (b) <= -1 - (a)) \ + || ((EXPR_SIGNED (_GL_INT_CONVERT (a, b)) || (tmax) < (b)) \ + && (tmax) < (a) + (b))) \ + : (tmax) < (b) || (tmax) - (b) < (a)) +#define _GL_INT_SUBTRACT_RANGE_OVERFLOW(a, b, tmin, tmax) \ + (((a) < 0) == ((b) < 0) \ + ? ((a) < (b) \ + ? !(tmin) || -1 - (tmin) < (b) - (a) - 1 \ + : (tmax) < (a) - (b)) \ + : (a) < 0 \ + ? ((!EXPR_SIGNED (_GL_INT_CONVERT ((a) - (tmin), b)) && (a) - (tmin) < 0) \ + || (a) - (tmin) < (b)) \ + : ((! (EXPR_SIGNED (_GL_INT_CONVERT (tmax, b)) \ + && EXPR_SIGNED (_GL_INT_CONVERT ((tmax) + (b), a))) \ + && (tmax) <= -1 - (b)) \ + || (tmax) + (b) < (a))) +#define _GL_INT_MULTIPLY_RANGE_OVERFLOW(a, b, tmin, tmax) \ + ((b) < 0 \ + ? ((a) < 0 \ + ? (EXPR_SIGNED (_GL_INT_CONVERT (tmax, b)) \ + ? (a) < (tmax) / (b) \ + : ((INT_NEGATE_OVERFLOW (b) \ + ? _GL_INT_CONVERT (b, tmax) >> (TYPE_WIDTH (b) - 1) \ + : (tmax) / -(b)) \ + <= -1 - (a))) \ + : INT_NEGATE_OVERFLOW (_GL_INT_CONVERT (b, tmin)) && (b) == -1 \ + ? (EXPR_SIGNED (a) \ + ? 0 < (a) + (tmin) \ + : 0 < (a) && -1 - (tmin) < (a) - 1) \ + : (tmin) / (b) < (a)) \ + : (b) == 0 \ + ? 0 \ + : ((a) < 0 \ + ? (INT_NEGATE_OVERFLOW (_GL_INT_CONVERT (a, tmin)) && (a) == -1 \ + ? (EXPR_SIGNED (b) ? 0 < (b) + (tmin) : -1 - (tmin) < (b) - 1) \ + : (tmin) / (a) < (b)) \ + : (tmax) / (b) < (a))) + #endif /* _GL_INTPROPS_H */ |