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Commit 4fd0cb61 authored by Yukihiro "Matz" Matsumoto's avatar Yukihiro "Matz" Matsumoto
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Merge pull request #3154 from cremno/improve-checked-mrb_int-arithmetic-implementation 

improve checked mrb int arithmetic implementation
parents bc715f99 7276e846
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Showing with 28 additions and 34 deletions
include/mruby/numeric.h
View file @ 4fd0cb61
...@@ -31,53 +31,47 @@ mrb_value mrb_fixnum_minus(mrb_state *mrb, mrb_value x, mrb_value y); ...@@ -31,53 +31,47 @@ mrb_value mrb_fixnum_minus(mrb_state *mrb, mrb_value x, mrb_value y);
mrb_value mrb_fixnum_mul(mrb_state *mrb, mrb_value x, mrb_value y); mrb_value mrb_fixnum_mul(mrb_state *mrb, mrb_value x, mrb_value y);
mrb_value mrb_num_div(mrb_state *mrb, mrb_value x, mrb_value y); mrb_value mrb_num_div(mrb_state *mrb, mrb_value x, mrb_value y);
#define MRB_UINT_MAKE2(n) uint ## n ## _t #ifndef __has_builtin
#define MRB_UINT_MAKE(n) MRB_UINT_MAKE2(n) #define __has_builtin(x) 0
#define mrb_uint MRB_UINT_MAKE(MRB_INT_BIT) #endif
#define MRB_INT_OVERFLOW_MASK ((mrb_uint)1 << (MRB_INT_BIT - 1 - MRB_FIXNUM_SHIFT))
/* Idea from Potion: https://github.com/perl11/potion (MIT) */ #if (defined(__GNUC__) && __GNUC__ >= 5) || \
#if (defined(__clang__) && ((__clang_major__ > 3) || (__clang_major__ == 3 && __clang_minor__ >= 4))) \ (__has_builtin(__builtin_add_overflow) && \
|| (defined(__GNUC__) && __GNUC__ >= 5) __has_builtin(__builtin_sub_overflow) && \
__has_builtin(__builtin_mul_overflow))
# define MRB_HAVE_TYPE_GENERIC_CHECKED_ARITHMETIC_BUILTINS
#endif
static inline mrb_bool #ifdef MRB_HAVE_TYPE_GENERIC_CHECKED_ARITHMETIC_BUILTINS
mrb_int_add_overflow(mrb_int augend, mrb_int addend, mrb_int *sum)
{
mrb_bool of;
#ifdef MRB_INT64 #ifndef MRB_WORD_BOXING
long long val; # define WBCHK(x) 0
of = __builtin_saddll_overflow(augend, addend, &val) ||
#else #else
int val; # define WBCHK(x) !FIXABLE(x)
of = __builtin_sadd_overflow(augend, addend, &val) ||
#endif #endif
(val > MRB_INT_MAX) || (val < MRB_INT_MIN);
*sum = (mrb_int) val; static inline mrb_bool
return of; mrb_int_add_overflow(mrb_int augend, mrb_int addend, mrb_int *sum)
{
return __builtin_add_overflow(augend, addend, sum) || WBCHK(*sum);
} }
static inline mrb_bool static inline mrb_bool
mrb_int_sub_overflow(mrb_int minuend, mrb_int subtrahend, mrb_int *difference) mrb_int_sub_overflow(mrb_int minuend, mrb_int subtrahend, mrb_int *difference)
{ {
mrb_bool of; return __builtin_sub_overflow(minuend, subtrahend, difference) || WBCHK(*difference);
}
#ifdef MRB_INT64 #undef WBCHK
long long val;
of = __builtin_ssubll_overflow(minuend, subtrahend, &val) ||
#else
int val;
of = __builtin_ssub_overflow(minuend, subtrahend, &val) ||
#endif
(val > MRB_INT_MAX) || (val < MRB_INT_MIN);
*difference = (mrb_int) val;
return of;
}
#else #else
#define MRB_UINT_MAKE2(n) uint ## n ## _t
#define MRB_UINT_MAKE(n) MRB_UINT_MAKE2(n)
#define mrb_uint MRB_UINT_MAKE(MRB_INT_BIT)
#define MRB_INT_OVERFLOW_MASK ((mrb_uint)1 << (MRB_INT_BIT - 1 - MRB_FIXNUM_SHIFT))
static inline mrb_bool static inline mrb_bool
mrb_int_add_overflow(mrb_int augend, mrb_int addend, mrb_int *sum) mrb_int_add_overflow(mrb_int augend, mrb_int addend, mrb_int *sum)
{ {
...@@ -98,13 +92,13 @@ mrb_int_sub_overflow(mrb_int minuend, mrb_int subtrahend, mrb_int *difference) ...@@ -98,13 +92,13 @@ mrb_int_sub_overflow(mrb_int minuend, mrb_int subtrahend, mrb_int *difference)
return !!(((x ^ z) & (~y ^ z)) & MRB_INT_OVERFLOW_MASK); return !!(((x ^ z) & (~y ^ z)) & MRB_INT_OVERFLOW_MASK);
} }
#endif
#undef MRB_INT_OVERFLOW_MASK #undef MRB_INT_OVERFLOW_MASK
#undef mrb_uint #undef mrb_uint
#undef MRB_UINT_MAKE #undef MRB_UINT_MAKE
#undef MRB_UINT_MAKE2 #undef MRB_UINT_MAKE2
#endif
MRB_END_DECL MRB_END_DECL
#endif /* MRUBY_NUMERIC_H */ #endif /* MRUBY_NUMERIC_H */
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