1 /* 2 * Copyright (c) Yann Collet, Facebook, Inc. 3 * All rights reserved. 4 * 5 * This source code is licensed under both the BSD-style license (found in the 6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found 7 * in the COPYING file in the root directory of this source tree). 8 * You may select, at your option, one of the above-listed licenses. 9 */ 10 11 #ifndef ZSTD_COMPILER_H 12 #define ZSTD_COMPILER_H 13 14 /*-******************************************************* 15 * Compiler specifics 16 *********************************************************/ 17 /* force inlining */ 18 19 #if (defined(__GNUC__) && !defined(__STRICT_ANSI__)) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L /* C99 */ 20 # define INLINE_KEYWORD inline 21 #else 22 # define INLINE_KEYWORD 23 #endif 24 25 #define FORCE_INLINE_ATTR __attribute__((always_inline)) 26 27 28 /* 29 On MSVC qsort requires that functions passed into it use the __cdecl calling conversion(CC). 30 This explictly marks such functions as __cdecl so that the code will still compile 31 if a CC other than __cdecl has been made the default. 32 */ 33 #define WIN_CDECL 34 35 /* 36 * FORCE_INLINE_TEMPLATE is used to define C "templates", which take constant 37 * parameters. They must be inlined for the compiler to eliminate the constant 38 * branches. 39 */ 40 #define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR 41 /* 42 * HINT_INLINE is used to help the compiler generate better code. It is *not* 43 * used for "templates", so it can be tweaked based on the compilers 44 * performance. 45 * 46 * gcc-4.8 and gcc-4.9 have been shown to benefit from leaving off the 47 * always_inline attribute. 48 * 49 * clang up to 5.0.0 (trunk) benefit tremendously from the always_inline 50 * attribute. 51 */ 52 #if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 8 && __GNUC__ < 5 53 # define HINT_INLINE static INLINE_KEYWORD 54 #else 55 # define HINT_INLINE static INLINE_KEYWORD FORCE_INLINE_ATTR 56 #endif 57 58 /* UNUSED_ATTR tells the compiler it is okay if the function is unused. */ 59 #define UNUSED_ATTR __attribute__((unused)) 60 61 /* force no inlining */ 62 #define FORCE_NOINLINE static __attribute__((__noinline__)) 63 64 65 /* target attribute */ 66 #ifndef __has_attribute 67 #define __has_attribute(x) 0 /* Compatibility with non-clang compilers. */ 68 #endif 69 #define TARGET_ATTRIBUTE(target) __attribute__((__target__(target))) 70 71 /* Enable runtime BMI2 dispatch based on the CPU. 72 * Enabled for clang & gcc >=4.8 on x86 when BMI2 isn't enabled by default. 73 */ 74 #ifndef DYNAMIC_BMI2 75 #if ((defined(__clang__) && __has_attribute(__target__)) \ 76 || (defined(__GNUC__) \ 77 && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))) \ 78 && (defined(__x86_64__) || defined(_M_X86)) \ 79 && !defined(__BMI2__) 80 # define DYNAMIC_BMI2 1 81 #else 82 # define DYNAMIC_BMI2 0 83 #endif 84 #endif 85 86 /* prefetch 87 * can be disabled, by declaring NO_PREFETCH build macro */ 88 #if ( (__GNUC__ >= 4) || ( (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) ) ) 89 # define PREFETCH_L1(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 3 /* locality */) 90 # define PREFETCH_L2(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 2 /* locality */) 91 #elif defined(__aarch64__) 92 # define PREFETCH_L1(ptr) __asm__ __volatile__("prfm pldl1keep, %0" ::"Q"(*(ptr))) 93 # define PREFETCH_L2(ptr) __asm__ __volatile__("prfm pldl2keep, %0" ::"Q"(*(ptr))) 94 #else 95 # define PREFETCH_L1(ptr) (void)(ptr) /* disabled */ 96 # define PREFETCH_L2(ptr) (void)(ptr) /* disabled */ 97 #endif /* NO_PREFETCH */ 98 99 #define CACHELINE_SIZE 64 100 101 #define PREFETCH_AREA(p, s) { \ 102 const char* const _ptr = (const char*)(p); \ 103 size_t const _size = (size_t)(s); \ 104 size_t _pos; \ 105 for (_pos=0; _pos<_size; _pos+=CACHELINE_SIZE) { \ 106 PREFETCH_L2(_ptr + _pos); \ 107 } \ 108 } 109 110 /* vectorization 111 * older GCC (pre gcc-4.3 picked as the cutoff) uses a different syntax */ 112 #if !defined(__INTEL_COMPILER) && !defined(__clang__) && defined(__GNUC__) 113 # if (__GNUC__ == 4 && __GNUC_MINOR__ > 3) || (__GNUC__ >= 5) 114 # define DONT_VECTORIZE __attribute__((optimize("no-tree-vectorize"))) 115 # else 116 # define DONT_VECTORIZE _Pragma("GCC optimize(\"no-tree-vectorize\")") 117 # endif 118 #else 119 # define DONT_VECTORIZE 120 #endif 121 122 /* Tell the compiler that a branch is likely or unlikely. 123 * Only use these macros if it causes the compiler to generate better code. 124 * If you can remove a LIKELY/UNLIKELY annotation without speed changes in gcc 125 * and clang, please do. 126 */ 127 #define LIKELY(x) (__builtin_expect((x), 1)) 128 #define UNLIKELY(x) (__builtin_expect((x), 0)) 129 130 /* disable warnings */ 131 132 /*Like DYNAMIC_BMI2 but for compile time determination of BMI2 support*/ 133 134 135 /* compat. with non-clang compilers */ 136 #ifndef __has_builtin 137 # define __has_builtin(x) 0 138 #endif 139 140 /* compat. with non-clang compilers */ 141 #ifndef __has_feature 142 # define __has_feature(x) 0 143 #endif 144 145 /* C-language Attributes are added in C23. */ 146 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ > 201710L) && defined(__has_c_attribute) 147 # define ZSTD_HAS_C_ATTRIBUTE(x) __has_c_attribute(x) 148 #else 149 # define ZSTD_HAS_C_ATTRIBUTE(x) 0 150 #endif 151 152 /* Only use C++ attributes in C++. Some compilers report support for C++ 153 * attributes when compiling with C. 154 */ 155 #define ZSTD_HAS_CPP_ATTRIBUTE(x) 0 156 157 /* Define ZSTD_FALLTHROUGH macro for annotating switch case with the 'fallthrough' attribute. 158 * - C23: https://en.cppreference.com/w/c/language/attributes/fallthrough 159 * - CPP17: https://en.cppreference.com/w/cpp/language/attributes/fallthrough 160 * - Else: __attribute__((__fallthrough__)) 161 */ 162 #define ZSTD_FALLTHROUGH fallthrough 163 164 /* detects whether we are being compiled under msan */ 165 166 167 /* detects whether we are being compiled under asan */ 168 169 170 #endif /* ZSTD_COMPILER_H */ 171