❯ pahole -C _PyCfgBasicblock Python/flowgraph.o

struct _PyCfgBasicblock {
	struct _PyCfgBasicblock *  b_list;               /*     0     8 */
	_PyJumpTargetLabel         b_label;              /*     8     4 */

	/* XXX 4 bytes hole, try to pack */

	struct _PyCfgExceptStack * b_exceptstack;        /*    16     8 */
	cfg_instr *                b_instr;              /*    24     8 */
	struct _PyCfgBasicblock *  b_next;               /*    32     8 */
	int                        b_iused;              /*    40     4 */
	int                        b_ialloc;             /*    44     4 */
	uint64_t                   b_unsafe_locals_mask; /*    48     8 */
	int                        b_predecessors;       /*    56     4 */
	int                        b_startdepth;         /*    60     4 */
	/* --- cacheline 1 boundary (64 bytes) --- */
	unsigned int               b_preserve_lasti:1;   /*    64: 0  4 */
	unsigned int               b_visited:1;          /*    64: 1  4 */
	unsigned int               b_except_handler:1;   /*    64: 2  4 */
	unsigned int               b_cold:1;             /*    64: 3  4 */
	unsigned int               b_warm:1;             /*    64: 4  4 */

	/* size: 72, cachelines: 2, members: 15 */
	/* sum members: 60, holes: 1, sum holes: 4 */
	/* sum bitfield members: 5 bits (0 bytes) */
	/* padding: 4 */
	/* bit_padding: 27 bits */
	/* last cacheline: 8 bytes */
};