'Unserialize some data.  *structptr* should be a pointer to
a {i8* data, i32 length} structure.'

def unserialize(self, structptr):

    fnty = Type.function(self.pyobj, (self.voidptr, ir.IntType(32)))
    fn = self._get_function(fnty, name='numba_unpickle')
    ptr = self.builder.extract_value(self.builder.load(structptr), 0)
    n = self.builder.extract_value(self.builder.load(structptr), 1)
    return self.builder.call(fn, (ptr, n))
