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 "FuzzerDefs.h"
12
13#if LIBFUZZER_LINUX || LIBFUZZER_NETBSD || LIBFUZZER_FREEBSD ||                \
14    LIBFUZZER_OPENBSD || LIBFUZZER_FUCHSIA || LIBFUZZER_EMSCRIPTEN
15__attribute__((weak)) extern uint8_t __start___libfuzzer_extra_counters;
16__attribute__((weak)) extern uint8_t __stop___libfuzzer_extra_counters;
17
18namespace fuzzer {
19uint8_t *ExtraCountersBegin() { return &__start___libfuzzer_extra_counters; }
20uint8_t *ExtraCountersEnd() { return &__stop___libfuzzer_extra_counters; }
21ATTRIBUTE_NO_SANITIZE_ALL
22void ClearExtraCounters() {  // hand-written memset, don't asan-ify.
23  uintptr_t *Beg = reinterpret_cast<uintptr_t*>(ExtraCountersBegin());
24  uintptr_t *End = reinterpret_cast<uintptr_t*>(ExtraCountersEnd());
25  for (; Beg < End; Beg++) {
26    *Beg = 0;
27    __asm__ __volatile__("" : : : "memory");
28  }
29}
30
31}  // namespace fuzzer
32
33#else
34// TODO: implement for other platforms.
35namespace fuzzer {
36uint8_t *ExtraCountersBegin() { return nullptr; }
37uint8_t *ExtraCountersEnd() { return nullptr; }
38void ClearExtraCounters() {}
39}  // namespace fuzzer
40
41#endif
42