1//===- FuzzerExtraCounters.cpp - Extra coverage counters ------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8// Extra coverage counters defined by user code.
9//===----------------------------------------------------------------------===//
10
11#include "FuzzerPlatform.h"
12#include <cstdint>
13
14#if LIBFUZZER_LINUX || LIBFUZZER_NETBSD || LIBFUZZER_FREEBSD ||                \
15    LIBFUZZER_FUCHSIA || LIBFUZZER_EMSCRIPTEN
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#endif
35