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(ZSTD_NO_INLINE) 20#if (defined(__GNUC__) && !defined(__STRICT_ANSI__)) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L /* C99 */ 21# define INLINE_KEYWORD inline 22#else 23# define INLINE_KEYWORD 24#endif 25 26#define FORCE_INLINE_ATTR __attribute__((always_inline)) 27 28#else 29 30#define INLINE_KEYWORD 31#define FORCE_INLINE_ATTR 32 33#endif 34 35/* 36 On MSVC qsort requires that functions passed into it use the __cdecl calling conversion(CC). 37 This explictly marks such functions as __cdecl so that the code will still compile 38 if a CC other than __cdecl has been made the default. 39*/ 40#define WIN_CDECL 41 42/* 43 * FORCE_INLINE_TEMPLATE is used to define C "templates", which take constant 44 * parameters. They must be inlined for the compiler to eliminate the constant 45 * branches. 46 */ 47#define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR 48/* 49 * HINT_INLINE is used to help the compiler generate better code. It is *not* 50 * used for "templates", so it can be tweaked based on the compilers 51 * performance. 52 * 53 * gcc-4.8 and gcc-4.9 have been shown to benefit from leaving off the 54 * always_inline attribute. 55 * 56 * clang up to 5.0.0 (trunk) benefit tremendously from the always_inline 57 * attribute. 58 */ 59#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 8 && __GNUC__ < 5 60# define HINT_INLINE static INLINE_KEYWORD 61#else 62# define HINT_INLINE static INLINE_KEYWORD FORCE_INLINE_ATTR 63#endif 64 65/* UNUSED_ATTR tells the compiler it is okay if the function is unused. */ 66#define UNUSED_ATTR __attribute__((unused)) 67 68/* force no inlining */ 69#define FORCE_NOINLINE static __attribute__((__noinline__)) 70 71 72/* target attribute */ 73#ifndef __has_attribute 74 #define __has_attribute(x) 0 /* Compatibility with non-clang compilers. */ 75#endif 76#define TARGET_ATTRIBUTE(target) __attribute__((__target__(target))) 77 78/* Enable runtime BMI2 dispatch based on the CPU. 79 * Enabled for clang & gcc >=4.8 on x86 when BMI2 isn't enabled by default. 80 */ 81#ifndef DYNAMIC_BMI2 82 #if ((defined(__clang__) && __has_attribute(__target__)) \ 83 || (defined(__GNUC__) \ 84 && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))) \ 85 && (defined(__x86_64__) || defined(_M_X86)) \ 86 && !defined(__BMI2__) 87 # define DYNAMIC_BMI2 1 88 #else 89 # define DYNAMIC_BMI2 0 90 #endif 91#endif 92 93/* prefetch 94 * can be disabled, by declaring NO_PREFETCH build macro */ 95#if ( (__GNUC__ >= 4) || ( (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) ) ) 96# define PREFETCH_L1(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 3 /* locality */) 97# define PREFETCH_L2(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 2 /* locality */) 98#elif defined(__aarch64__) 99# define PREFETCH_L1(ptr) __asm__ __volatile__("prfm pldl1keep, %0" ::"Q"(*(ptr))) 100# define PREFETCH_L2(ptr) __asm__ __volatile__("prfm pldl2keep, %0" ::"Q"(*(ptr))) 101#else 102# define PREFETCH_L1(ptr) (void)(ptr) /* disabled */ 103# define PREFETCH_L2(ptr) (void)(ptr) /* disabled */ 104#endif /* NO_PREFETCH */ 105 106#define CACHELINE_SIZE 64 107 108#define PREFETCH_AREA(p, s) { \ 109 const char* const _ptr = (const char*)(p); \ 110 size_t const _size = (size_t)(s); \ 111 size_t _pos; \ 112 for (_pos=0; _pos<_size; _pos+=CACHELINE_SIZE) { \ 113 PREFETCH_L2(_ptr + _pos); \ 114 } \ 115} 116 117/* vectorization 118 * older GCC (pre gcc-4.3 picked as the cutoff) uses a different syntax */ 119#if !defined(__INTEL_COMPILER) && !defined(__clang__) && defined(__GNUC__) 120# if (__GNUC__ == 4 && __GNUC_MINOR__ > 3) || (__GNUC__ >= 5) 121# define DONT_VECTORIZE __attribute__((optimize("no-tree-vectorize"))) 122# else 123# define DONT_VECTORIZE _Pragma("GCC optimize(\"no-tree-vectorize\")") 124# endif 125#else 126# define DONT_VECTORIZE 127#endif 128 129/* Tell the compiler that a branch is likely or unlikely. 130 * Only use these macros if it causes the compiler to generate better code. 131 * If you can remove a LIKELY/UNLIKELY annotation without speed changes in gcc 132 * and clang, please do. 133 */ 134#define LIKELY(x) (__builtin_expect((x), 1)) 135#define UNLIKELY(x) (__builtin_expect((x), 0)) 136 137/* disable warnings */ 138 139/*Like DYNAMIC_BMI2 but for compile time determination of BMI2 support*/ 140 141 142/* compat. with non-clang compilers */ 143#ifndef __has_builtin 144# define __has_builtin(x) 0 145#endif 146 147/* compat. with non-clang compilers */ 148#ifndef __has_feature 149# define __has_feature(x) 0 150#endif 151 152/* C-language Attributes are added in C23. */ 153#if defined(__STDC_VERSION__) && (__STDC_VERSION__ > 201710L) && defined(__has_c_attribute) 154# define ZSTD_HAS_C_ATTRIBUTE(x) __has_c_attribute(x) 155#else 156# define ZSTD_HAS_C_ATTRIBUTE(x) 0 157#endif 158 159/* Only use C++ attributes in C++. Some compilers report support for C++ 160 * attributes when compiling with C. 161 */ 162#define ZSTD_HAS_CPP_ATTRIBUTE(x) 0 163 164/* Define ZSTD_FALLTHROUGH macro for annotating switch case with the 'fallthrough' attribute. 165 * - C23: https://en.cppreference.com/w/c/language/attributes/fallthrough 166 * - CPP17: https://en.cppreference.com/w/cpp/language/attributes/fallthrough 167 * - Else: __attribute__((__fallthrough__)) 168 */ 169#define ZSTD_FALLTHROUGH fallthrough 170 171/* detects whether we are being compiled under msan */ 172 173 174/* detects whether we are being compiled under asan */ 175 176 177#endif /* ZSTD_COMPILER_H */ 178