1//===- FuzzerExtraCounters.cpp - Extra coverage counters ------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9// Extra coverage counters defined by user code.
10//===----------------------------------------------------------------------===//
11
12#include "FuzzerDefs.h"
13
14#if LIBFUZZER_LINUX || LIBFUZZER_NETBSD || LIBFUZZER_FREEBSD ||                \
15    LIBFUZZER_OPENBSD
16__attribute__((weak)) extern uint8_t __start___libfuzzer_extra_counters;
17__attribute__((weak)) extern uint8_t __stop___libfuzzer_extra_counters;
18
19namespace fuzzer {
20uint8_t *ExtraCountersBegin() { return &__start___libfuzzer_extra_counters; }
21uint8_t *ExtraCountersEnd() { return &__stop___libfuzzer_extra_counters; }
22ATTRIBUTE_NO_SANITIZE_ALL
23void ClearExtraCounters() {  // hand-written memset, don't asan-ify.
24  uintptr_t *Beg = reinterpret_cast<uintptr_t*>(ExtraCountersBegin());
25  uintptr_t *End = reinterpret_cast<uintptr_t*>(ExtraCountersEnd());
26  for (; Beg < End; Beg++) {
27    *Beg = 0;
28    __asm__ __volatile__("" : : : "memory");
29  }
30}
31
32}  // namespace fuzzer
33
34#else
35// TODO: implement for other platforms.
36namespace fuzzer {
37uint8_t *ExtraCountersBegin() { return nullptr; }
38uint8_t *ExtraCountersEnd() { return nullptr; }
39void ClearExtraCounters() {}
40}  // namespace fuzzer
41
42#endif
43