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FuzzerExtraCounters.cpp revision 1.1.1.1.6.2 
      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 {
     20 uint8_t *ExtraCountersBegin() { return &__start___libfuzzer_extra_counters; }
     21 uint8_t *ExtraCountersEnd() { return &__stop___libfuzzer_extra_counters; }
     22 ATTRIBUTE_NO_SANITIZE_ALL
     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 {
     37 uint8_t *ExtraCountersBegin() { return nullptr; }
     38 uint8_t *ExtraCountersEnd() { return nullptr; }
     39 void ClearExtraCounters() {}
     40 }  // namespace fuzzer
     41 
     42 #endif
     43