On Thu, May 04, 2023 at 05:09:01PM -0700, Andrii Nakryiko wrote:
> +struct backtrack_state {
> + struct bpf_verifier_env *env;
> + u32 frame;
> + u32 bitcnt;
> + u32 reg_masks[MAX_CALL_FRAMES];
> + u64 stack_masks[MAX_CALL_FRAMES];
> +};
> +
> +static inline u32 bt_empty(struct backtrack_state *bt)
> +{
> + u64 mask = 0;
> + int i;
> +
> + for (i = 0; i < MAX_CALL_FRAMES; i++)
> + mask |= bt->reg_masks[i] | bt->stack_masks[i];
> +
> + return mask == 0;
> +}
> +
...
> +static inline void bt_set_frame_reg(struct backtrack_state *bt, u32 frame, u32 reg)
> +{
> + if (bt->reg_masks[frame] & (1 << reg))
> + return;
> +
> + bt->reg_masks[frame] |= 1 << reg;
> + bt->bitcnt++;
> +}
So you went with bitcnt and bt_empty ?
I'm confused. I thought we discussed it's one or another.
I have slight preference towards bt_empty() as above. fwiw.
