1#include "src/__support/CPP/bit.h"
2#include "src/__support/big_int.h"
3#include "src/string/memory_utils/inline_memcpy.h"
4
5using namespace LIBC_NAMESPACE;
6
7// Helper function when using gdb / lldb to set a breakpoint and inspect values.
8template <typename T> void debug_and_trap(const char *msg, T a, T b) {
9 __builtin_trap();
10}
11
12#define DEBUG_AND_TRAP()
13
14#define TEST_BINOP(OP) \
15 if ((a OP b) != (static_cast<T>(BigInt(a) OP BigInt(b)))) \
16 debug_and_trap(#OP, a, b);
17
18#define TEST_SHIFTOP(OP) \
19 if ((a OP b) != (static_cast<T>(BigInt(a) OP b))) \
20 debug_and_trap(#OP, a, b);
21
22#define TEST_FUNCTION(FUN) \
23 if (FUN(a) != FUN(BigInt(a))) \
24 debug_and_trap(#FUN, a, b);
25
26// Test that basic arithmetic operations of BigInt behave like their scalar
27// counterparts.
28template <typename T, typename BigInt> void run_tests(T a, T b) {
29 TEST_BINOP(+)
30 TEST_BINOP(-)
31 TEST_BINOP(*)
32 if (b != 0)
33 TEST_BINOP(/)
34 if (b >= 0 && b < cpp::numeric_limits<T>::digits) {
35 TEST_SHIFTOP(<<)
36 TEST_SHIFTOP(>>)
37 }
38 if constexpr (!BigInt::SIGNED) {
39 TEST_FUNCTION(cpp::has_single_bit)
40 TEST_FUNCTION(cpp::countr_zero)
41 TEST_FUNCTION(cpp::countl_zero)
42 TEST_FUNCTION(cpp::countl_one)
43 TEST_FUNCTION(cpp::countr_one)
44 }
45}
46
47// Reads a T from libfuzzer data.
48template <typename T> T read(const uint8_t *data, size_t &remainder) {
49 T out = 0;
50 constexpr size_t T_SIZE = sizeof(T);
51 const size_t copy_size = remainder < T_SIZE ? remainder : T_SIZE;
52 inline_memcpy(&out, data, copy_size);
53 remainder -= copy_size;
54 return out;
55}
56
57template <typename T, typename BigInt>
58void run_tests(const uint8_t *data, size_t size) {
59 const auto a = read<T>(data, size);
60 const auto b = read<T>(data, size);
61 run_tests<T, BigInt>(a, b);
62}
63
64extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
65 // unsigned
66 run_tests<uint64_t, BigInt<64, false, uint16_t>>(data, size);
67 // signed
68 run_tests<int64_t, BigInt<64, true, uint16_t>>(data, size);
69 return 0;
70}
71

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