Found while debugging #339, Related to #337
((Real*)x)->obj, a reference from T_DATA to VALUE, will be garbled after gc compaction.
typedef struct {
VALUE obj; /* Back pointer(VALUE) for Ruby object. */
size_t MaxPrec;
size_t Prec;
SIGNED_VALUE exponent;
short sign;
short flag;
DECDIG frac[FLEXIBLE_ARRAY_SIZE];
} Real;After compaction, obj can be a reference to any kind of object.
The usage of obj field is limited. We should remove it from struct.
Reproduction code
p BigDecimal::VERSION
#=> "3.1.9", "3.2.1"
x = BigDecimal('1.5')
nan = BigDecimal("NaN")
inf = BigDecimal("Infinity")
GC.verify_compaction_references(expand_heap: true, toward: :empty)
x.divmod(inf) # Segfault
x.remainder(inf) # Segfault
nan + nan # Segfault
nan - nan # Segfault
BigMath.log(x, 10) # ??? can't be coerced into BigDecimal (TypeError)
BigMath.exp(x, 10) # Segfault
x**x # ??? can't be coerced into BigDecimal (ArgumentError)
x.power(x, 10) # ??? can't be coerced into BigDecimal (ArgumentError)
Found while debugging #339, Related to #337
((Real*)x)->obj, a reference from T_DATA to VALUE, will be garbled after gc compaction.After compaction,
objcan be a reference to any kind of object.The usage of obj field is limited. We should remove it from struct.
Reproduction code