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 18 namespace fuzzer { 19 uint8_t *ExtraCountersBegin() { return &__start___libfuzzer_extra_counters; } 20 uint8_t *ExtraCountersEnd() { return &__stop___libfuzzer_extra_counters; } 21 ATTRIBUTE_NO_SANITIZE_ALL 22 void 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. 35 namespace fuzzer { 36 uint8_t *ExtraCountersBegin() { return nullptr; } 37 uint8_t *ExtraCountersEnd() { return nullptr; } 38 void ClearExtraCounters() {} 39 } // namespace fuzzer 40 41 #endif 42