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authorPaul Eggert <eggert@cs.ucla.edu>2019-08-14 18:13:27 -0700
committerPaul Eggert <eggert@cs.ucla.edu>2019-08-14 18:13:54 -0700
commitaa1411b20fba73ca6fde90fc9ce62cc8a854bf20 (patch)
treed390dc726f47658c684d3b2cc1e1b6137b198c16 /lib/intprops.h
parent370f07046b13035948655d450ed1b58d20a0cdd4 (diff)
downloademacs-aa1411b20fba73ca6fde90fc9ce62cc8a854bf20.tar.gz
Update from Gnulib
This incorporates: 2019-08-14 intprops: pacify picky GCC 2019-08-14 intprops: support unsigned *_WRAPV results 2019-08-12 verify: improve diagnostic quality in recent GCC * lib/intprops.h, lib/verify.h: Copy from Gnulib.
Diffstat (limited to 'lib/intprops.h')
-rw-r--r--lib/intprops.h156
1 files changed, 128 insertions, 28 deletions
diff --git a/lib/intprops.h b/lib/intprops.h
index 1a44ae55653..d1785ac6f16 100644
--- a/lib/intprops.h
+++ b/lib/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)) \
@@ -281,7 +281,9 @@
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 +311,12 @@
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 *. The result type must be either signed, or an
+ unsigned type that is 'unsigned int' or wider. Because the WRAPV
+ macros convert the result, the 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. */
@@ -348,11 +353,21 @@
/* 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)
+ _GL_INT_OP_WRAPV (a, b, r, +, __builtin_add_overflow, \
+ _GL_INT_ADD_RANGE_OVERFLOW)
#define INT_SUBTRACT_WRAPV(a, b, r) \
- _GL_INT_OP_WRAPV (a, b, r, -, __builtin_sub_overflow, INT_SUBTRACT_OVERFLOW)
+ _GL_INT_OP_WRAPV (a, b, r, -, __builtin_sub_overflow, \
+ _GL_INT_SUBTRACT_RANGE_OVERFLOW)
#define INT_MULTIPLY_WRAPV(a, b, r) \
- _GL_INT_OP_WRAPV (a, b, r, *, __builtin_mul_overflow, INT_MULTIPLY_OVERFLOW)
+ _GL_INT_OP_WRAPV (a, b, r, *, _GL_BUILTIN_MUL_OVERFLOW, \
+ _GL_INT_MULTIPLY_RANGE_OVERFLOW)
+
+/* Like __builtin_mul_overflow, but work around GCC bug 91450. */
+#define _GL_BUILTIN_MUL_OVERFLOW(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))
/* Nonzero if this compiler has GCC bug 68193 or Clang bug 25390. See:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68193
@@ -379,41 +394,79 @@
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, ULLONG_MIN, ULLONG_MAX)))
#else
+/* This fallback implementation uses _GL_SIGNED_TYPE_OR_EXPR, and so
+ may guess wrong on some non-GNU pre-C11 compilers when the type of
+ *R is unsigned char or unsigned short. This is why the
+ documentation for INT_ADD_WRAPV says that the result type, if
+ unsigned, should be unsigned int or wider. */
# 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 int, \
- signed char, SCHAR_MIN, SCHAR_MAX) \
+ ? (_GL_SIGNED_TYPE_OR_EXPR (*(r)) \
+ ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
+ signed char, SCHAR_MIN, SCHAR_MAX) \
+ : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
+ unsigned char, 0, 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_SIGNED_TYPE_OR_EXPR (*(r)) \
+ ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
+ short int, SHRT_MIN, SHRT_MAX) \
+ : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
+ unsigned short int, 0, 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 +475,7 @@
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 +499,57 @@
#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 */