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 #include "portability_macros.h" 15 16 /*-******************************************************* 17 * Compiler specifics 18 *********************************************************/ 19 /* force inlining */ 20 21 #if !defined(ZSTD_NO_INLINE) 22 #if (defined(__GNUC__) && !defined(__STRICT_ANSI__)) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L /* C99 */ 23 # define INLINE_KEYWORD inline 24 #else 25 # define INLINE_KEYWORD 26 #endif 27 28 #define FORCE_INLINE_ATTR __attribute__((always_inline)) 29 30 #else 31 32 #define INLINE_KEYWORD 33 #define FORCE_INLINE_ATTR 34 35 #endif 36 37 /* 38 On MSVC qsort requires that functions passed into it use the __cdecl calling conversion(CC). 39 This explicitly marks such functions as __cdecl so that the code will still compile 40 if a CC other than __cdecl has been made the default. 41 */ 42 #define WIN_CDECL 43 44 /* 45 * FORCE_INLINE_TEMPLATE is used to define C "templates", which take constant 46 * parameters. They must be inlined for the compiler to eliminate the constant 47 * branches. 48 */ 49 #define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR 50 /* 51 * HINT_INLINE is used to help the compiler generate better code. It is *not* 52 * used for "templates", so it can be tweaked based on the compilers 53 * performance. 54 * 55 * gcc-4.8 and gcc-4.9 have been shown to benefit from leaving off the 56 * always_inline attribute. 57 * 58 * clang up to 5.0.0 (trunk) benefit tremendously from the always_inline 59 * attribute. 60 */ 61 #if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 8 && __GNUC__ < 5 62 # define HINT_INLINE static INLINE_KEYWORD 63 #else 64 # define HINT_INLINE static INLINE_KEYWORD FORCE_INLINE_ATTR 65 #endif 66 67 /* UNUSED_ATTR tells the compiler it is okay if the function is unused. */ 68 #define UNUSED_ATTR __attribute__((unused)) 69 70 /* force no inlining */ 71 #define FORCE_NOINLINE static __attribute__((__noinline__)) 72 73 74 /* target attribute */ 75 #define TARGET_ATTRIBUTE(target) __attribute__((__target__(target))) 76 77 /* Target attribute for BMI2 dynamic dispatch. 78 * Enable lzcnt, bmi, and bmi2. 79 * We test for bmi1 & bmi2. lzcnt is included in bmi1. 80 */ 81 #define BMI2_TARGET_ATTRIBUTE TARGET_ATTRIBUTE("lzcnt,bmi,bmi2") 82 83 /* prefetch 84 * can be disabled, by declaring NO_PREFETCH build macro */ 85 #if ( (__GNUC__ >= 4) || ( (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) ) ) 86 # define PREFETCH_L1(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 3 /* locality */) 87 # define PREFETCH_L2(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 2 /* locality */) 88 #elif defined(__aarch64__) 89 # define PREFETCH_L1(ptr) __asm__ __volatile__("prfm pldl1keep, %0" ::"Q"(*(ptr))) 90 # define PREFETCH_L2(ptr) __asm__ __volatile__("prfm pldl2keep, %0" ::"Q"(*(ptr))) 91 #else 92 # define PREFETCH_L1(ptr) (void)(ptr) /* disabled */ 93 # define PREFETCH_L2(ptr) (void)(ptr) /* disabled */ 94 #endif /* NO_PREFETCH */ 95 96 #define CACHELINE_SIZE 64 97 98 #define PREFETCH_AREA(p, s) { \ 99 const char* const _ptr = (const char*)(p); \ 100 size_t const _size = (size_t)(s); \ 101 size_t _pos; \ 102 for (_pos=0; _pos<_size; _pos+=CACHELINE_SIZE) { \ 103 PREFETCH_L2(_ptr + _pos); \ 104 } \ 105 } 106 107 /* vectorization 108 * older GCC (pre gcc-4.3 picked as the cutoff) uses a different syntax, 109 * and some compilers, like Intel ICC and MCST LCC, do not support it at all. */ 110 #if !defined(__INTEL_COMPILER) && !defined(__clang__) && defined(__GNUC__) && !defined(__LCC__) 111 # if (__GNUC__ == 4 && __GNUC_MINOR__ > 3) || (__GNUC__ >= 5) 112 # define DONT_VECTORIZE __attribute__((optimize("no-tree-vectorize"))) 113 # else 114 # define DONT_VECTORIZE _Pragma("GCC optimize(\"no-tree-vectorize\")") 115 # endif 116 #else 117 # define DONT_VECTORIZE 118 #endif 119 120 /* Tell the compiler that a branch is likely or unlikely. 121 * Only use these macros if it causes the compiler to generate better code. 122 * If you can remove a LIKELY/UNLIKELY annotation without speed changes in gcc 123 * and clang, please do. 124 */ 125 #define LIKELY(x) (__builtin_expect((x), 1)) 126 #define UNLIKELY(x) (__builtin_expect((x), 0)) 127 128 #if __has_builtin(__builtin_unreachable) || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5))) 129 # define ZSTD_UNREACHABLE { assert(0), __builtin_unreachable(); } 130 #else 131 # define ZSTD_UNREACHABLE { assert(0); } 132 #endif 133 134 /* disable warnings */ 135 136 /*Like DYNAMIC_BMI2 but for compile time determination of BMI2 support*/ 137 138 139 /* compile time determination of SIMD support */ 140 141 /* C-language Attributes are added in C23. */ 142 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ > 201710L) && defined(__has_c_attribute) 143 # define ZSTD_HAS_C_ATTRIBUTE(x) __has_c_attribute(x) 144 #else 145 # define ZSTD_HAS_C_ATTRIBUTE(x) 0 146 #endif 147 148 /* Only use C++ attributes in C++. Some compilers report support for C++ 149 * attributes when compiling with C. 150 */ 151 #define ZSTD_HAS_CPP_ATTRIBUTE(x) 0 152 153 /* Define ZSTD_FALLTHROUGH macro for annotating switch case with the 'fallthrough' attribute. 154 * - C23: https://en.cppreference.com/w/c/language/attributes/fallthrough 155 * - CPP17: https://en.cppreference.com/w/cpp/language/attributes/fallthrough 156 * - Else: __attribute__((__fallthrough__)) 157 */ 158 #define ZSTD_FALLTHROUGH fallthrough 159 160 /*-************************************************************** 161 * Alignment check 162 *****************************************************************/ 163 164 /* this test was initially positioned in mem.h, 165 * but this file is removed (or replaced) for linux kernel 166 * so it's now hosted in compiler.h, 167 * which remains valid for both user & kernel spaces. 168 */ 169 170 #ifndef ZSTD_ALIGNOF 171 /* covers gcc, clang & MSVC */ 172 /* note : this section must come first, before C11, 173 * due to a limitation in the kernel source generator */ 174 # define ZSTD_ALIGNOF(T) __alignof(T) 175 176 #endif /* ZSTD_ALIGNOF */ 177 178 /*-************************************************************** 179 * Sanitizer 180 *****************************************************************/ 181 182 183 184 #endif /* ZSTD_COMPILER_H */ 185