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Use GCC/Clang builtins for overflows checking #4447

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Use GCC/Clang builtins for overflows checking #4447

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43 changes: 38 additions & 5 deletions librz/include/rz_types_overflow.h
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Original file line number Diff line number Diff line change
Expand Up @@ -2,12 +2,24 @@
#define RZ_TYPES_OVERFLOW_H

#include <rz_types.h>
#include <rz_userconf.h>

// TODO: Use CLANG/GCC builtins if available: __builtin_mul_overflow
// Using compiler builtins when available

// ADD
// if ((x > 0) && (a > INT_MAX - x)) /* `a + x` would overflow */;
// if ((x < 0) && (a < INT_MIN - x)) /* `a + x` would underflow */;
#if HAVE___BUILTIN_ADD_OVERFLOW
#define SZT_ADD_OVFCHK(x, y) __builtin_add_overflow_p (x, y, (__typeof__ ((x) + (y))) 0)
#define SZT_ADD_OVFCHK(x, y) __builtin_add_overflow_p (x, y, (__typeof__ ((x) + (y))) 0)
#define SSZT_ADD_OVFCHK(a, x) __builtin_add_overflow_p (a, x, (__typeof__ ((a) + (x))) 0)
#define UT64_ADD_OVFCHK(x, y) __builtin_add_overflow_p (x, y, (__typeof__ ((x) + (y))) 0)
#define ST64_ADD_OVFCHK(a, x) __builtin_add_overflow_p (a, x, (__typeof__ ((a) + (x))) 0)
#define UT32_ADD_OVFCHK(x, y) __builtin_add_overflow_p (x, y, (__typeof__ ((x) + (y))) 0)
#define ST32_ADD_OVFCHK(a, x) __builtin_add_overflow_p (a, x, (__typeof__ ((a) + (x))) 0)
#define UT16_ADD_OVFCHK(x, y) __builtin_add_overflow_p (x, y, (__typeof__ ((x) + (y))) 0)
#define ST16_ADD_OVFCHK(a, b) __builtin_add_overflow_p (a, b, (__typeof__ ((a) + (b))) 0)
#define UT8_ADD_OVFCHK(x, y) __builtin_add_overflow_p (x, y, (__typeof__ ((x) + (y))) 0)
#define ST8_ADD_OVFCHK(a, x) __builtin_add_overflow_p (a, x, (__typeof__ ((a) + (x))) 0)
#else
#define SZT_ADD_OVFCHK(x, y) ((SIZE_MAX - (x)) < (y))
#define SSZT_ADD_OVFCHK(a, x) ((((x) > 0) && ((a) > SSIZE_MAX - (x))) || (((x) < 0) && (a) < SSIZE_MIN - (x)))
#define UT64_ADD_OVFCHK(x, y) ((UT64_MAX - (x)) < (y))
Expand All @@ -18,10 +30,21 @@
#define ST16_ADD_OVFCHK(a, b) ((((b) > 0) && ((a) > ST16_MAX - (b))) || (((b) < 0) && ((a) < ST16_MIN - (b))))
#define UT8_ADD_OVFCHK(x, y) ((UT8_MAX - (x)) < (y))
#define ST8_ADD_OVFCHK(a, x) ((((x) > 0) && ((a) > ST8_MAX - (x))) || ((x) < 0 && (a) < ST8_MIN - (x)))
#endif

// SUB
// if ((x < 0) && (a > INT_MAX + x)) /* `a - x` would overflow */;
// if ((x > 0) && (a < INT_MIN + x)) /* `a - x` would underflow */;
#if HAVE___BUILTIN_SUB_OVERFLOW
#define SZT_SUB_OVFCHK(a, b) __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0)
#define SSZT_SUB_OVFCHK(a, b) __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0)
#define UT64_SUB_OVFCHK(a, b) __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0)
#define ST64_SUB_OVFCHK(a, b) __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0)
#define UT32_SUB_OVFCHK(a, b) __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0)
#define ST32_SUB_OVFCHK(a, b) __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0)
#define UT16_SUB_OVFCHK(a, b) __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0)
#define ST16_SUB_OVFCHK(a, b) __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0)
#define UT8_SUB_OVFCHK(a, b) __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0)
#define ST8_SUB_OVFCHK(a, b) __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0)
#else
#define SZT_SUB_OVFCHK(a, b) SZT_ADD_OVFCHK(a, -(b))
#define SSZT_SUB_OVFCHK(a, b) SSZT_ADD_OVFCHK(a, -(b))
#define UT64_SUB_OVFCHK(a, b) UT64_ADD_OVFCHK(a, -(b))
Expand All @@ -32,13 +55,21 @@
#define ST16_SUB_OVFCHK(a, b) ST16_ADD_OVFCHK(a, -(b))
#define UT8_SUB_OVFCHK(a, b) UT8_ADD_OVFCHK(a, -(b))
#define ST8_SUB_OVFCHK(a, b) ST8_ADD_OVFCHK(a, -(b))
#endif

// MUL
#define UNSIGNED_MUL_OVERFLOW_CHECK(overflow_name, type_base, type_min, type_max) \
static inline bool overflow_name(type_base a, type_base b) { \
return (a > 0 && b > 0 && a > type_max / b); \
}


#if HAVE___BUILTIN_MUL_OVERFLOW
#define SIGNED_MUL_OVERFLOW_CHECK(overflow_name, type_base, type_min, type_max) \
static inline bool overflow_name(type_base a, type_base b) { \
return __builtin_mul_overflow_p(a, b, (__typeof__ ((a) * (b))) 0); \
}
#else
#define SIGNED_MUL_OVERFLOW_CHECK(overflow_name, type_base, type_min, type_max) \
static inline bool overflow_name(type_base a, type_base b) { \
if (a > 0) { \
Expand All @@ -52,11 +83,13 @@
} \
return a && b < type_max / a; \
}
#endif

#define SIGNED_DIV_OVERFLOW_CHECK(overflow_name, type_base, type_mid, type_max) \
static inline bool overflow_name(type_base a, type_base b) { \
return (!b || (a == type_mid && b == type_max)); \
}

#define UNSIGNED_DIV_OVERFLOW_CHECK(overflow_name, type_base, type_min, type_max) \
static inline bool overflow_name(type_base a, type_base b) { \
(void)a; \
Expand Down
3 changes: 3 additions & 0 deletions librz/include/rz_userconf.h.in
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,9 @@
#define HAVE___BUILTIN_BSWAP32 @HAVE___BUILTIN_BSWAP32@
#define HAVE___BUILTIN_BSWAP64 @HAVE___BUILTIN_BSWAP64@
#define HAVE___BUILTIN_CLZLL @HAVE___BUILTIN_CLZLL@
#define HAVE___BUILTIN_ADD_OVERFLOW @HAVE___BUILTIN_ADD_OVERFLOW_P@
#define HAVE___BUILTIN_SUB_OVERFLOW @HAVE___BUILTIN_SUB_OVERFLOW_P@
#define HAVE___BUILTIN_MUL_OVERFLOW @HAVE___BUILTIN_MUL_OVERFLOW_P@
#define HAVE_POSIX_MEMALIGN @HAVE_POSIX_MEMALIGN@
#define HAVE__ALIGNED_MALLOC @HAVE__ALIGNED_MALLOC@

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3 changes: 3 additions & 0 deletions meson.build
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Original file line number Diff line number Diff line change
Expand Up @@ -465,6 +465,9 @@ foreach it : ccs
['__builtin_bswap32', '', []],
['__builtin_bswap64', '', []],
['__builtin_clzll', '', []],
['__builtin_add_overflow_p', '', []],
['__builtin_sub_overflow_p', '', []],
['__builtin_mul_overflow_p', '', []],
['posix_memalign', '#include <stdlib.h>', []],
['_aligned_malloc', '#include <malloc.h>', []],
]
Expand Down
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