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Add an appropriate fallback to hb_int_mul_overflows

This commit is contained in:
Ebrahim Byagowi 2020-04-16 21:25:32 +04:30
parent 32f431406e
commit 9ffa50fe5d
3 changed files with 15 additions and 10 deletions
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15
src/hb-algs.hh
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@ -645,16 +645,17 @@ hb_unsigned_mul_overflows (unsigned int count, unsigned int size)
return (size > 0) && (count >= ((unsigned int) -1) / size); return (size > 0) && (count >= ((unsigned int) -1) / size);
} }
/* Right now we only have one use for signed overflow and as it static inline bool
* is GCC 5.1 > and clang we don't care about its fallback ATM */ hb_int_mul_overflows (int x, int y, int &result)
#ifndef __has_builtin {
# define __has_builtin(x) 0
#endif
#if __has_builtin(__builtin_mul_overflow) #if __has_builtin(__builtin_mul_overflow)
# define hb_signed_mul_overflows(x, y, result) __builtin_mul_overflow(x, y, &result) return __builtin_mul_overflow (x, y, &result);
#else #else
# define hb_signed_mul_overflows(x, y, result) (result = (x) * (y), false) int64_t sink = (int64_t) x * y;
result = sink;
return result != sink;
#endif #endif
}
/* /*

6
src/hb-ot-var-avar-table.hh
View File

@ -90,9 +90,9 @@ struct SegmentMaps : ArrayOf<AxisValueMap>
return arrayZ[i-1].toCoord; return arrayZ[i-1].toCoord;
int factor; int factor;
if (hb_signed_mul_overflows (arrayZ[i].toCoord - arrayZ[i-1].toCoord, if (unlikely (hb_int_mul_overflows (arrayZ[i].toCoord - arrayZ[i-1].toCoord,
value - arrayZ[i-1].fromCoord, value - arrayZ[i-1].fromCoord,
factor)) factor)))
return arrayZ[i-1].toCoord; return arrayZ[i-1].toCoord;
int denom = arrayZ[i].fromCoord - arrayZ[i-1].fromCoord; int denom = arrayZ[i].fromCoord - arrayZ[i-1].fromCoord;

4
src/hb.hh
View File

@ -219,6 +219,10 @@ extern "C" void hb_free_impl(void *ptr);
* Compiler attributes * Compiler attributes
*/ */
#ifndef __has_builtin
# define __has_builtin(x) 0
#endif
#if (defined(__GNUC__) || defined(__clang__)) && defined(__OPTIMIZE__) #if (defined(__GNUC__) || defined(__clang__)) && defined(__OPTIMIZE__)
#define likely(expr) (__builtin_expect (!!(expr), 1)) #define likely(expr) (__builtin_expect (!!(expr), 1))
#define unlikely(expr) (__builtin_expect (!!(expr), 0)) #define unlikely(expr) (__builtin_expect (!!(expr), 0))