llvm-capstone/compiler-rt/test/fuzzer/TableLookupTest.cpp
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

46 lines
1.4 KiB
C++

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// Make sure the fuzzer eventually finds all possible values of a variable
// within a range.
#include <cassert>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <set>
const size_t N = 1 << 12;
// Define an array of counters that will be understood by libFuzzer
// as extra coverage signal. The array must be:
// * uint8_t
// * in the section named __libfuzzer_extra_counters.
// The target code may declare more than one such array.
//
// Use either `Counters[Idx] = 1` or `Counters[Idx]++;`
// depending on whether multiple occurrences of the event 'Idx'
// is important to distinguish from one occurrence.
#ifdef __linux__
__attribute__((section("__libfuzzer_extra_counters")))
#endif
static uint8_t Counters[N];
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
static std::set<uint16_t> SeenIdx;
if (Size != 4) return 0;
uint32_t Idx;
memcpy(&Idx, Data, 4);
Idx %= N;
assert(Counters[Idx] == 0); // libFuzzer should reset these between the runs.
// Or Counters[Idx]=1 if we don't care how many times this happened.
Counters[Idx]++;
SeenIdx.insert(Idx);
if (SeenIdx.size() == N) {
fprintf(stderr, "BINGO: found all values\n");
abort();
}
return 0;
}