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py/objfloat: Fix undefined shifting behavior in high-quality float hash.

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When computing e.g. hash(0.4e3) with ubsan enabled, a diagnostic like the
following would occur:

    ../../py/objfloat.c:91:30: runtime error: shift exponent 44 is too
    large for 32-bit type 'int'

By casting constant "1" to the right type the intended value is preserved.
This commit is contained in:
Jeff Epler 2018-05-19 11:25:03 -05:00 committed by Damien George
parent 4f71a2a75a
commit 60eb5305f6
1 changed files with 1 additions and 1 deletions
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py/objfloat.c
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@ -88,7 +88,7 @@ typedef uint32_t mp_float_uint_t;
if (adj_exp <= MP_FLOAT_FRAC_BITS) { if (adj_exp <= MP_FLOAT_FRAC_BITS) {
// number may have a fraction; xor the integer part with the fractional part // number may have a fraction; xor the integer part with the fractional part
val = (frc >> (MP_FLOAT_FRAC_BITS - adj_exp)) val = (frc >> (MP_FLOAT_FRAC_BITS - adj_exp))
^ (frc & ((1 << (MP_FLOAT_FRAC_BITS - adj_exp)) - 1)); ^ (frc & (((mp_float_uint_t)1 << (MP_FLOAT_FRAC_BITS - adj_exp)) - 1));
} else if ((unsigned int)adj_exp < BITS_PER_BYTE * sizeof(mp_int_t) - 1) { } else if ((unsigned int)adj_exp < BITS_PER_BYTE * sizeof(mp_int_t) - 1) {
// the number is a (big) whole integer and will fit in val's signed-width // the number is a (big) whole integer and will fit in val's signed-width
val = (mp_int_t)frc << (adj_exp - MP_FLOAT_FRAC_BITS); val = (mp_int_t)frc << (adj_exp - MP_FLOAT_FRAC_BITS);