FuzzerBuiltinsMsvc.h revision 360784 
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 "FuzzerDefs.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
26namespace fuzzer {
27
28inline 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.
31inline uint16_t Bswap(uint16_t x) { return _byteswap_ushort(x); }
32inline uint32_t Bswap(uint32_t x) { return _byteswap_ulong(x); }
33inline 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.
38inline 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>(63 - (LeadZeroIdx + 32)); // Create a bit offset from the MSB.
45  // Scan the low 32 bits.
46  if (_BitScanReverse(&LeadZeroIdx, static_cast<unsigned long>(X)))
47    return static_cast<int>(63 - LeadZeroIdx);
48
49#else
50  if (_BitScanReverse64(&LeadZeroIdx, X)) return 63 - LeadZeroIdx;
51#endif
52  return 64;
53}
54
55inline uint32_t Clz(uint32_t X) {
56  unsigned long LeadZeroIdx = 0;
57  if (_BitScanReverse(&LeadZeroIdx, X)) return 31 - LeadZeroIdx;
58  return 32;
59}
60
61inline int Popcountll(unsigned long long X) {
62#if !defined(_M_ARM) && !defined(_M_X64)
63  return __popcnt(X) + __popcnt(X >> 32);
64#else
65  return __popcnt64(X);
66#endif
67}
68
69}  // namespace fuzzer
70
71#endif  // LIBFUZER_MSVC
72#endif  // LLVM_FUZZER_BUILTINS_MSVC_H
73