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 
19 namespace fuzzer {
ExtraCountersBegin()20 uint8_t *ExtraCountersBegin() { return &__start___libfuzzer_extra_counters; }
ExtraCountersEnd()21 uint8_t *ExtraCountersEnd() { return &__stop___libfuzzer_extra_counters; }
22 ATTRIBUTE_NO_SANITIZE_ALL
ClearExtraCounters()23 void 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.
36 namespace fuzzer {
ExtraCountersBegin()37 uint8_t *ExtraCountersBegin() { return nullptr; }
ExtraCountersEnd()38 uint8_t *ExtraCountersEnd() { return nullptr; }
ClearExtraCounters()39 void ClearExtraCounters() {}
40 }  // namespace fuzzer
41 
42 #endif
43