enabled neverZero feature again
MODIFY
gcc_plugin/afl-gcc-rt.o.c
gcc_plugin/afl-gcc-rt.o.c
GCC integration design is based on the LLVM design, which comes
from Laszlo Szekeres.
- Copyright 2015 Google Inc. All rights reserved.
-
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at:
@@ -55,15 +53,13 @@ __thread u32 __afl_prev_loc;
#endif
/* Trace a basic block with some ID */
-void __afl_trace(u32 x) {
-
- u32 l = __afl_prev_loc;
+void __afl_trace(const u32 x) {
-#if 0 /* enable for neverZero feature. By default disabled since too inefficient :-( */
- /* @Marc: avoid conditional jumps here */
- __afl_area_ptr[l ^ x] += 1 + (__afl_area_ptr[l ^ x] == (u8)~0);
+#if 1 /* enable for neverZero feature. */
+ __afl_area_ptr[__afl_prev_loc ^ x] += 1
+ + ((u8)(1 + __afl_area_ptr[__afl_prev_loc ^ x]) == 0);
#else
- ++__afl_area_ptr[l ^ x];
+ ++__afl_area_ptr[__afl_prev_loc ^ x];
#endif
__afl_prev_loc = (x >> 1);

enabled neverZero feature again