in helpers/trace_helpers.c [897:912]
static void print_stars(unsigned int val, unsigned int val_max, int width)
{
int num_stars, num_spaces, i;
bool need_plus;
num_stars = min(val, val_max) * width / val_max;
num_spaces = width - num_stars;
need_plus = val > val_max;
for (i = 0; i < num_stars; i++)
printf("*");
for (i = 0; i < num_spaces; i++)
printf(" ");
if (need_plus)
printf("+");
}