1// -*- C++ -*- 2//===----------------------- support/win32/support.h ----------------------===// 3// 4// The LLVM Compiler Infrastructure 5// 6// This file is dual licensed under the MIT and the University of Illinois Open 7// Source Licenses. See LICENSE.TXT for details. 8// 9//===----------------------------------------------------------------------===// 10 11#ifndef _LIBCPP_SUPPORT_WIN32_SUPPORT_H 12#define _LIBCPP_SUPPORT_WIN32_SUPPORT_H 13 14// Functions and constants used in libc++ that 15// are missing from the Windows C library. 16 17#include <wchar.h> // mbstate_t 18#include <cstdarg> // va_ macros 19// "builtins" not implemented here for Clang or GCC as they provide 20// implementations. Assuming required for elsewhere else, certainly MSVC. 21#if defined(_LIBCPP_MSVC) 22#include <intrin.h> 23#endif 24#if defined(_LIBCPP_MSVCRT) 25#include <xlocinfo.h> 26#endif 27#define swprintf _snwprintf 28#define vswprintf _vsnwprintf 29 30#ifndef NOMINMAX 31#define NOMINMAX 32#endif 33 34extern "C" { 35 36int vasprintf(char **sptr, const char *__restrict fmt, va_list ap); 37int asprintf(char **sptr, const char *__restrict fmt, ...); 38size_t mbsnrtowcs(wchar_t *__restrict dst, const char **__restrict src, 39 size_t nmc, size_t len, mbstate_t *__restrict ps); 40size_t wcsnrtombs(char *__restrict dst, const wchar_t **__restrict src, 41 size_t nwc, size_t len, mbstate_t *__restrict ps); 42} 43 44#if defined(_LIBCPP_MSVCRT) 45#define snprintf _snprintf 46#define atoll _atoi64 47#define strtoll _strtoi64 48#define strtoull _strtoui64 49#define wcstoll _wcstoi64 50#define wcstoull _wcstoui64 51_LIBCPP_ALWAYS_INLINE float strtof(const char *nptr, char **endptr) 52{ 53 return _Stof(nptr, endptr, 0); 54} 55_LIBCPP_ALWAYS_INLINE double strtod(const char *nptr, char **endptr) 56{ 57 return _Stod(nptr, endptr, 0); 58} 59_LIBCPP_ALWAYS_INLINE long double strtold(const char *nptr, char **endptr) 60{ 61 return _Stold(nptr, endptr, 0); 62} 63 64#define _Exit _exit 65#endif 66 67#if defined(_LIBCPP_MSVC) 68 69// Bit builtin's make these assumptions when calling _BitScanForward/Reverse 70// etc. These assumptions are expected to be true for Win32/Win64 which this 71// file supports. 72static_assert(sizeof(unsigned long long) == 8, ""); 73static_assert(sizeof(unsigned long) == 4, ""); 74static_assert(sizeof(unsigned int) == 4, ""); 75 76_LIBCPP_ALWAYS_INLINE int __builtin_popcount(unsigned int x) 77{ 78 // Binary: 0101... 79 static const unsigned int m1 = 0x55555555; 80 // Binary: 00110011.. 81 static const unsigned int m2 = 0x33333333; 82 // Binary: 4 zeros, 4 ones ... 83 static const unsigned int m4 = 0x0f0f0f0f; 84 // The sum of 256 to the power of 0,1,2,3... 85 static const unsigned int h01 = 0x01010101; 86 // Put count of each 2 bits into those 2 bits. 87 x -= (x >> 1) & m1; 88 // Put count of each 4 bits into those 4 bits. 89 x = (x & m2) + ((x >> 2) & m2); 90 // Put count of each 8 bits into those 8 bits. 91 x = (x + (x >> 4)) & m4; 92 // Returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24). 93 return (x * h01) >> 24; 94} 95 96_LIBCPP_ALWAYS_INLINE int __builtin_popcountl(unsigned long x) 97{ 98 return __builtin_popcount(static_cast<int>(x)); 99} 100 101_LIBCPP_ALWAYS_INLINE int __builtin_popcountll(unsigned long long x) 102{ 103 // Binary: 0101... 104 static const unsigned long long m1 = 0x5555555555555555; 105 // Binary: 00110011.. 106 static const unsigned long long m2 = 0x3333333333333333; 107 // Binary: 4 zeros, 4 ones ... 108 static const unsigned long long m4 = 0x0f0f0f0f0f0f0f0f; 109 // The sum of 256 to the power of 0,1,2,3... 110 static const unsigned long long h01 = 0x0101010101010101; 111 // Put count of each 2 bits into those 2 bits. 112 x -= (x >> 1) & m1; 113 // Put count of each 4 bits into those 4 bits. 114 x = (x & m2) + ((x >> 2) & m2); 115 // Put count of each 8 bits into those 8 bits. 116 x = (x + (x >> 4)) & m4; 117 // Returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24) + ... 118 return static_cast<int>((x * h01) >> 56); 119} 120 121// Returns the number of trailing 0-bits in x, starting at the least significant 122// bit position. If x is 0, the result is undefined. 123_LIBCPP_ALWAYS_INLINE int __builtin_ctzll(unsigned long long mask) 124{ 125 unsigned long where; 126// Search from LSB to MSB for first set bit. 127// Returns zero if no set bit is found. 128#if defined(_WIN64) 129 if (_BitScanForward64(&where, mask)) 130 return static_cast<int>(where); 131#elif defined(_WIN32) 132 // Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls. 133 // Scan the Low Word. 134 if (_BitScanForward(&where, static_cast<unsigned long>(mask))) 135 return static_cast<int>(where); 136 // Scan the High Word. 137 if (_BitScanForward(&where, static_cast<unsigned long>(mask >> 32))) 138 return static_cast<int>(where + 32); // Create a bit offset from the LSB. 139#else 140#error "Implementation of __builtin_ctzll required" 141#endif 142 return 64; 143} 144 145_LIBCPP_ALWAYS_INLINE int __builtin_ctzl(unsigned long mask) 146{ 147 unsigned long where; 148 // Search from LSB to MSB for first set bit. 149 // Returns zero if no set bit is found. 150 if (_BitScanForward(&where, mask)) 151 return static_cast<int>(where); 152 return 32; 153} 154 155_LIBCPP_ALWAYS_INLINE int __builtin_ctz(unsigned int mask) 156{ 157 // Win32 and Win64 expectations. 158 static_assert(sizeof(mask) == 4, ""); 159 static_assert(sizeof(unsigned long) == 4, ""); 160 return __builtin_ctzl(static_cast<unsigned long>(mask)); 161} 162 163// Returns the number of leading 0-bits in x, starting at the most significant 164// bit position. If x is 0, the result is undefined. 165_LIBCPP_ALWAYS_INLINE int __builtin_clzll(unsigned long long mask) 166{ 167 unsigned long where; 168// BitScanReverse scans from MSB to LSB for first set bit. 169// Returns 0 if no set bit is found. 170#if defined(_WIN64) 171 if (_BitScanReverse64(&where, mask)) 172 return static_cast<int>(63 - where); 173#elif defined(_WIN32) 174 // Scan the high 32 bits. 175 if (_BitScanReverse(&where, static_cast<unsigned long>(mask >> 32))) 176 return static_cast<int>(63 - 177 (where + 32)); // Create a bit offset from the MSB. 178 // Scan the low 32 bits. 179 if (_BitScanReverse(&where, static_cast<unsigned long>(mask))) 180 return static_cast<int>(63 - where); 181#else 182#error "Implementation of __builtin_clzll required" 183#endif 184 return 64; // Undefined Behavior. 185} 186 187_LIBCPP_ALWAYS_INLINE int __builtin_clzl(unsigned long mask) 188{ 189 unsigned long where; 190 // Search from LSB to MSB for first set bit. 191 // Returns zero if no set bit is found. 192 if (_BitScanReverse(&where, mask)) 193 return static_cast<int>(31 - where); 194 return 32; // Undefined Behavior. 195} 196 197_LIBCPP_ALWAYS_INLINE int __builtin_clz(unsigned int x) 198{ 199 return __builtin_clzl(x); 200} 201#endif // _LIBCPP_MSVC 202 203#endif // _LIBCPP_SUPPORT_WIN32_SUPPORT_H 204