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 /* target attribute */ 74 #define TARGET_ATTRIBUTE(target) __attribute__((__target__(target))) 75 76 /* Target attribute for BMI2 dynamic dispatch. 77 * Enable lzcnt, bmi, and bmi2. 78 * We test for bmi1 & bmi2. lzcnt is included in bmi1. 79 */ 80 #define BMI2_TARGET_ATTRIBUTE TARGET_ATTRIBUTE("lzcnt,bmi,bmi2") 81 82 /* prefetch 83 * can be disabled, by declaring NO_PREFETCH build macro */ 84 #if ( (__GNUC__ >= 4) || ( (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) ) ) 85 # define PREFETCH_L1(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 3 /* locality */) 86 # define PREFETCH_L2(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 2 /* locality */) 87 #elif defined(__aarch64__) 88 # define PREFETCH_L1(ptr) __asm__ __volatile__("prfm pldl1keep, %0" ::"Q"(*(ptr))) 89 # define PREFETCH_L2(ptr) __asm__ __volatile__("prfm pldl2keep, %0" ::"Q"(*(ptr))) 90 #else 91 # define PREFETCH_L1(ptr) (void)(ptr) /* disabled */ 92 # define PREFETCH_L2(ptr) (void)(ptr) /* disabled */ 93 #endif /* NO_PREFETCH */ 94 95 #define CACHELINE_SIZE 64 96 97 #define PREFETCH_AREA(p, s) { \ 98 const char* const _ptr = (const char*)(p); \ 99 size_t const _size = (size_t)(s); \ 100 size_t _pos; \ 101 for (_pos=0; _pos<_size; _pos+=CACHELINE_SIZE) { \ 102 PREFETCH_L2(_ptr + _pos); \ 103 } \ 104 } 105 106 /* vectorization 107 * older GCC (pre gcc-4.3 picked as the cutoff) uses a different syntax, 108 * and some compilers, like Intel ICC and MCST LCC, do not support it at all. */ 109 #if !defined(__INTEL_COMPILER) && !defined(__clang__) && defined(__GNUC__) && !defined(__LCC__) 110 # if (__GNUC__ == 4 && __GNUC_MINOR__ > 3) || (__GNUC__ >= 5) 111 # define DONT_VECTORIZE __attribute__((optimize("no-tree-vectorize"))) 112 # else 113 # define DONT_VECTORIZE _Pragma("GCC optimize(\"no-tree-vectorize\")") 114 # endif 115 #else 116 # define DONT_VECTORIZE 117 #endif 118 119 /* Tell the compiler that a branch is likely or unlikely. 120 * Only use these macros if it causes the compiler to generate better code. 121 * If you can remove a LIKELY/UNLIKELY annotation without speed changes in gcc 122 * and clang, please do. 123 */ 124 #define LIKELY(x) (__builtin_expect((x), 1)) 125 #define UNLIKELY(x) (__builtin_expect((x), 0)) 126 127 #if __has_builtin(__builtin_unreachable) || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5))) 128 # define ZSTD_UNREACHABLE { assert(0), __builtin_unreachable(); } 129 #else 130 # define ZSTD_UNREACHABLE { assert(0); } 131 #endif 132 133 /* disable warnings */ 134 135 /*Like DYNAMIC_BMI2 but for compile time determination of BMI2 support*/ 136 137 /* compile time determination of SIMD support */ 138 139 /* C-language Attributes are added in C23. */ 140 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ > 201710L) && defined(__has_c_attribute) 141 # define ZSTD_HAS_C_ATTRIBUTE(x) __has_c_attribute(x) 142 #else 143 # define ZSTD_HAS_C_ATTRIBUTE(x) 0 144 #endif 145 146 /* Only use C++ attributes in C++. Some compilers report support for C++ 147 * attributes when compiling with C. 148 */ 149 #define ZSTD_HAS_CPP_ATTRIBUTE(x) 0 150 151 /* Define ZSTD_FALLTHROUGH macro for annotating switch case with the 'fallthrough' attribute. 152 * - C23: https://en.cppreference.com/w/c/language/attributes/fallthrough 153 * - CPP17: https://en.cppreference.com/w/cpp/language/attributes/fallthrough 154 * - Else: __attribute__((__fallthrough__)) 155 */ 156 #define ZSTD_FALLTHROUGH fallthrough 157 158 /*-************************************************************** 159 * Alignment check 160 *****************************************************************/ 161 162 /* this test was initially positioned in mem.h, 163 * but this file is removed (or replaced) for linux kernel 164 * so it's now hosted in compiler.h, 165 * which remains valid for both user & kernel spaces. 166 */ 167 168 #ifndef ZSTD_ALIGNOF 169 /* covers gcc, clang & MSVC */ 170 /* note : this section must come first, before C11, 171 * due to a limitation in the kernel source generator */ 172 # define ZSTD_ALIGNOF(T) __alignof(T) 173 174 #endif /* ZSTD_ALIGNOF */ 175 176 /*-************************************************************** 177 * Sanitizer 178 *****************************************************************/ 179 180 #endif /* ZSTD_COMPILER_H */ 181