use type-generic checked arithmetic builtins

Version checking is not reliable - especially with Clang.
E.g. Apple's Clang (Xcode) uses different version numbers.
A feature check (__has_builtin) is the recommened way.

Add the MRB_HAVE_TYPE_GENERIC_CHECKED_ARITHMETIC_BUILTINS
macro which may be used in other files.
This commit is contained in:
cremno
2016-05-09 16:31:57 +02:00
parent 39b6a9dafc
commit 7276e84637
+23 -29
View File
@@ -31,45 +31,39 @@ 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_num_div(mrb_state *mrb, mrb_value x, mrb_value y);
/* Idea from Potion: https://github.com/perl11/potion (MIT) */
#if (defined(__clang__) && ((__clang_major__ > 3) || (__clang_major__ == 3 && __clang_minor__ >= 4))) \
|| (defined(__GNUC__) && __GNUC__ >= 5)
#ifndef __has_builtin
#define __has_builtin(x) 0
#endif
#if (defined(__GNUC__) && __GNUC__ >= 5) || \
(__has_builtin(__builtin_add_overflow) && \
__has_builtin(__builtin_sub_overflow) && \
__has_builtin(__builtin_mul_overflow))
# define MRB_HAVE_TYPE_GENERIC_CHECKED_ARITHMETIC_BUILTINS
#endif
#ifdef MRB_HAVE_TYPE_GENERIC_CHECKED_ARITHMETIC_BUILTINS
#ifndef MRB_WORD_BOXING
# define WBCHK(x) 0
#else
# define WBCHK(x) !FIXABLE(x)
#endif
static inline mrb_bool
mrb_int_add_overflow(mrb_int augend, mrb_int addend, mrb_int *sum)
{
mrb_bool of;
#ifdef MRB_INT64
long long val;
of = __builtin_saddll_overflow(augend, addend, &val) ||
#else
int val;
of = __builtin_sadd_overflow(augend, addend, &val) ||
#endif
(val > MRB_INT_MAX) || (val < MRB_INT_MIN);
*sum = (mrb_int) val;
return of;
return __builtin_add_overflow(augend, addend, sum) || WBCHK(*sum);
}
static inline mrb_bool
mrb_int_sub_overflow(mrb_int minuend, mrb_int subtrahend, mrb_int *difference)
{
mrb_bool of;
#ifdef MRB_INT64
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;
return __builtin_sub_overflow(minuend, subtrahend, difference) || WBCHK(*difference);
}
#undef WBCHK
#else
#define MRB_UINT_MAKE2(n) uint ## n ## _t