1 //===- FuzzerBuiltinsMSVC.h - Internal header for builtins ------*- C++ -* ===// 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 // Wrapper functions and marcos that use intrinsics instead of builtin functions 9 // which cannot be compiled by MSVC. 10 //===----------------------------------------------------------------------===// 11 12 #ifndef LLVM_FUZZER_BUILTINS_MSVC_H 13 #define LLVM_FUZZER_BUILTINS_MSVC_H 14 15 #include "FuzzerPlatform.h" 16 17 #if LIBFUZZER_MSVC 18 #include <intrin.h> 19 #include <cstdint> 20 #include <cstdlib> 21 22 // __builtin_return_address() cannot be compiled with MSVC. Use the equivalent 23 // from <intrin.h> 24 #define GET_CALLER_PC() _ReturnAddress() 25 26 namespace fuzzer { 27 28 inline uint8_t Bswap(uint8_t x) { return x; } 29 // Use alternatives to __builtin functions from <stdlib.h> and <intrin.h> on 30 // Windows since the builtins are not supported by MSVC. 31 inline uint16_t Bswap(uint16_t x) { return _byteswap_ushort(x); } 32 inline uint32_t Bswap(uint32_t x) { return _byteswap_ulong(x); } 33 inline uint64_t Bswap(uint64_t x) { return _byteswap_uint64(x); } 34 35 // The functions below were mostly copied from 36 // compiler-rt/lib/builtins/int_lib.h which defines the __builtin functions used 37 // outside of Windows. 38 inline uint32_t Clzll(uint64_t X) { 39 unsigned long LeadZeroIdx = 0; 40 41 #if !defined(_M_ARM) && !defined(_M_X64) 42 // Scan the high 32 bits. 43 if (_BitScanReverse(&LeadZeroIdx, static_cast<unsigned long>(X >> 32))) 44 return static_cast<int>( 45 63 - (LeadZeroIdx + 32)); // Create a bit offset from the MSB. 46 // Scan the low 32 bits. 47 if (_BitScanReverse(&LeadZeroIdx, static_cast<unsigned long>(X))) 48 return static_cast<int>(63 - LeadZeroIdx); 49 50 #else 51 if (_BitScanReverse64(&LeadZeroIdx, X)) return 63 - LeadZeroIdx; 52 #endif 53 return 64; 54 } 55 56 inline int Popcountll(unsigned long long X) { 57 #if !defined(_M_ARM) && !defined(_M_X64) 58 return __popcnt(X) + __popcnt(X >> 32); 59 #else 60 return __popcnt64(X); 61 #endif 62 } 63 64 } // namespace fuzzer 65 66 #endif // LIBFUZER_MSVC 67 #endif // LLVM_FUZZER_BUILTINS_MSVC_H 68