1//===-- uint_fuzz.cpp -----------------------------------------------------===//
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///
9/// Fuzzing test for llvm-libc unsigned integer utilities.
10///
11//===----------------------------------------------------------------------===//
12#include "src/__support/CPP/bit.h"
13#include "src/__support/big_int.h"
14#include "src/string/memory_utils/inline_memcpy.h"
15
16using namespace LIBC_NAMESPACE;
17
18// Helper function when using gdb / lldb to set a breakpoint and inspect values.
19template <typename T> void debug_and_trap(const char *msg, T a, T b) {
20 __builtin_trap();
21}
22
23#define DEBUG_AND_TRAP()
24
25#define TEST_BINOP(OP) \
26 if ((a OP b) != (static_cast<T>(BigInt(a) OP BigInt(b)))) \
27 debug_and_trap(#OP, a, b);
28
29#define TEST_SHIFTOP(OP) \
30 if ((a OP b) != (static_cast<T>(BigInt(a) OP b))) \
31 debug_and_trap(#OP, a, b);
32
33#define TEST_FUNCTION(FUN) \
34 if (FUN(a) != FUN(BigInt(a))) \
35 debug_and_trap(#FUN, a, b);
36
37// Test that basic arithmetic operations of BigInt behave like their scalar
38// counterparts.
39template <typename T, typename BigInt> void run_tests(T a, T b) {
40 TEST_BINOP(+)
41 TEST_BINOP(-)
42 TEST_BINOP(*)
43 if (b != 0)
44 TEST_BINOP(/)
45 if (b >= 0 && b < cpp::numeric_limits<T>::digits) {
46 TEST_SHIFTOP(<<)
47 TEST_SHIFTOP(>>)
48 }
49 if constexpr (!BigInt::SIGNED) {
50 TEST_FUNCTION(cpp::has_single_bit)
51 TEST_FUNCTION(cpp::countr_zero)
52 TEST_FUNCTION(cpp::countl_zero)
53 TEST_FUNCTION(cpp::countl_one)
54 TEST_FUNCTION(cpp::countr_one)
55 }
56}
57
58// Reads a T from libfuzzer data.
59template <typename T> T read(const uint8_t *data, size_t &remainder) {
60 T out = 0;
61 constexpr size_t T_SIZE = sizeof(T);
62 const size_t copy_size = remainder < T_SIZE ? remainder : T_SIZE;
63 inline_memcpy(&out, data, copy_size);
64 remainder -= copy_size;
65 return out;
66}
67
68template <typename T, typename BigInt>
69void run_tests(const uint8_t *data, size_t size) {
70 const auto a = read<T>(data, size);
71 const auto b = read<T>(data, size);
72 run_tests<T, BigInt>(a, b);
73}
74
75extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
76 // unsigned
77 run_tests<uint64_t, BigInt<64, false, uint16_t>>(data, size);
78 // signed
79 run_tests<int64_t, BigInt<64, true, uint16_t>>(data, size);
80 return 0;
81}
82

source code of libc/fuzzing/__support/uint_fuzz.cpp