implement neverZero counter for __afl_trace()
MODIFY
gcc_plugin/afl-gcc-rt.o.c
gcc_plugin/afl-gcc-rt.o.c
@@ -50,8 +50,10 @@ static u8 is_persistent;
void __afl_trace(u32 x) {
u32 l = __afl_prev_loc;
- u32 n = l ^ x;
- *(__afl_area_ptr + n) += 1;
+ const u32 n = l ^ x;
+ u8 *const bitmap_ptr = __afl_area_ptr + n;
+ *bitmap_ptr += 1 + (*bitmap_ptr == (u8)~0); /* neverZero */
+
__afl_prev_loc = (x >> 1);
return;

implement neverZero counter for __afl_trace()