module/zstd/lib/common/compiler.h

   1 /*
   2  * Copyright (c) 2016-2020, 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 #if defined(__GNUC__) || defined(__ICCARM__)
  27 #  define FORCE_INLINE_ATTR __attribute__((always_inline))
  28 #elif defined(_MSC_VER)
  29 #  define FORCE_INLINE_ATTR __forceinline
  30 #else
  31 #  define FORCE_INLINE_ATTR
  32 #endif
  33
  34 #else
  35
  36 #define INLINE_KEYWORD
  37 #define FORCE_INLINE_ATTR
  38
  39 #endif
  40
  41 /**
  42  * FORCE_INLINE_TEMPLATE is used to define C "templates", which take constant
  43  * parameters. They must be inlined for the compiler to eliminate the constant
  44  * branches.
  45  */
  46 #define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR
  47 /**
  48  * HINT_INLINE is used to help the compiler generate better code. It is *not*
  49  * used for "templates", so it can be tweaked based on the compilers
  50  * performance.
  51  *
  52  * gcc-4.8 and gcc-4.9 have been shown to benefit from leaving off the
  53  * always_inline attribute.
  54  *
  55  * clang up to 5.0.0 (trunk) benefit tremendously from the always_inline
  56  * attribute.
  57  */
  58 #if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 8 && __GNUC__ < 5
  59 #  define HINT_INLINE static INLINE_KEYWORD
  60 #else
  61 #  define HINT_INLINE static INLINE_KEYWORD FORCE_INLINE_ATTR
  62 #endif
  63
  64 /* UNUSED_ATTR tells the compiler it is okay if the function is unused. */
  65 #if defined(__GNUC__)
  66 #  define UNUSED_ATTR __attribute__((unused))
  67 #else
  68 #  define UNUSED_ATTR
  69 #endif
  70
  71 /* force no inlining */
  72 #ifdef _MSC_VER
  73 #  define FORCE_NOINLINE static __declspec(noinline)
  74 #else
  75 #  if defined(__GNUC__) || defined(__ICCARM__)
  76 #    define FORCE_NOINLINE static __attribute__((__noinline__))
  77 #  else
  78 #    define FORCE_NOINLINE static
  79 #  endif
  80 #endif
  81
  82 /* target attribute */
  83 #ifndef __has_attribute
  84   #define __has_attribute(x) 0  /* Compatibility with non-clang compilers. */
  85 #endif
  86 #if defined(__GNUC__) || defined(__ICCARM__)
  87 #  define TARGET_ATTRIBUTE(target) __attribute__((__target__(target)))
  88 #else
  89 #  define TARGET_ATTRIBUTE(target)
  90 #endif
  91
  92 /* Enable runtime BMI2 dispatch based on the CPU.
  93  * Enabled for clang & gcc >=4.8 on x86 when BMI2 isn't enabled by default.
  94  */
  95 #ifndef DYNAMIC_BMI2
  96   #if ((defined(__clang__) && __has_attribute(__target__)) \
  97       || (defined(__GNUC__) \
  98           && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))) \
  99       && (defined(__x86_64__) || defined(_M_X86)) \
 100       && !defined(__BMI2__)
 101   #  define DYNAMIC_BMI2 1
 102   #else
 103   #  define DYNAMIC_BMI2 0
 104   #endif
 105 #endif
 106
 107 /* prefetch
 108  * can be disabled, by declaring NO_PREFETCH build macro */
 109 #if defined(NO_PREFETCH)
 110 #  define PREFETCH_L1(ptr)  (void)(ptr)  /* disabled */
 111 #  define PREFETCH_L2(ptr)  (void)(ptr)  /* disabled */
 112 #else
 113 #  if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86))  /* _mm_prefetch() is not defined outside of x86/x64 */
 114 #    include <mmintrin.h>   /* https://msdn.microsoft.com/fr-fr/library/84szxsww(v=vs.90).aspx */
 115 #    define PREFETCH_L1(ptr)  _mm_prefetch((const char*)(ptr), _MM_HINT_T0)
 116 #    define PREFETCH_L2(ptr)  _mm_prefetch((const char*)(ptr), _MM_HINT_T1)
 117 #    elif defined(__aarch64__)
 118 #     define PREFETCH_L1(ptr)  __asm__ __volatile__("prfm pldl1keep, %0" ::"Q"(*(ptr)))
 119 #     define PREFETCH_L2(ptr)  __asm__ __volatile__("prfm pldl2keep, %0" ::"Q"(*(ptr)))
 120 #  elif defined(__GNUC__) && ( (__GNUC__ >= 4) || ( (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) ) )
 121 #    define PREFETCH_L1(ptr)  __builtin_prefetch((ptr), 0 /* rw==read */, 3 /* locality */)
 122 #    define PREFETCH_L2(ptr)  __builtin_prefetch((ptr), 0 /* rw==read */, 2 /* locality */)
 123 #  else
 124 #    define PREFETCH_L1(ptr) (void)(ptr)  /* disabled */
 125 #    define PREFETCH_L2(ptr) (void)(ptr)  /* disabled */
 126 #  endif
 127 #endif  /* NO_PREFETCH */
 128
 129 #define CACHELINE_SIZE 64
 130
 131 #define PREFETCH_AREA(p, s)  {            \
 132     const char* const _ptr = (const char*)(p);  \
 133     size_t const _size = (size_t)(s);     \
 134     size_t _pos;                          \
 135     for (_pos=0; _pos<_size; _pos+=CACHELINE_SIZE) {  \
 136         PREFETCH_L2(_ptr + _pos);         \
 137     }                                     \
 138 }
 139
 140 /* vectorization
 141  * older GCC (pre gcc-4.3 picked as the cutoff) uses a different syntax */
 142 #if !defined(__INTEL_COMPILER) && !defined(__clang__) && defined(__GNUC__)
 143 #  if (__GNUC__ == 4 && __GNUC_MINOR__ > 3) || (__GNUC__ >= 5)
 144 #    define DONT_VECTORIZE __attribute__((optimize("no-tree-vectorize")))
 145 #  else
 146 #    define DONT_VECTORIZE _Pragma("GCC optimize(\"no-tree-vectorize\")")
 147 #  endif
 148 #else
 149 #  define DONT_VECTORIZE
 150 #endif
 151
 152 /* Tell the compiler that a branch is likely or unlikely.
 153  * Only use these macros if it causes the compiler to generate better code.
 154  * If you can remove a LIKELY/UNLIKELY annotation without speed changes in gcc
 155  * and clang, please do.
 156  */
 157 #if defined(__GNUC__)
 158 #define LIKELY(x) (__builtin_expect((x), 1))
 159 #define UNLIKELY(x) (__builtin_expect((x), 0))
 160 #else
 161 #define LIKELY(x) (x)
 162 #define UNLIKELY(x) (x)
 163 #endif
 164
 165 /* disable warnings */
 166 #ifdef _MSC_VER    /* Visual Studio */
 167 #  include <intrin.h>                    /* For Visual 2005 */
 168 #  pragma warning(disable : 4100)        /* disable: C4100: unreferenced formal parameter */
 169 #  pragma warning(disable : 4127)        /* disable: C4127: conditional expression is constant */
 170 #  pragma warning(disable : 4204)        /* disable: C4204: non-constant aggregate initializer */
 171 #  pragma warning(disable : 4214)        /* disable: C4214: non-int bitfields */
 172 #  pragma warning(disable : 4324)        /* disable: C4324: padded structure */
 173 #endif
 174
 175 #endif /* ZSTD_COMPILER_H */