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compiler.h
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1 /*
2  * Copyright (c) 2016-present, 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 #if defined (__GNUC__) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L /* C99 */
19 # define INLINE_KEYWORD inline
20 #else
21 # define INLINE_KEYWORD
22 #endif
23 
24 #if defined(__GNUC__)
25 # define FORCE_INLINE_ATTR __attribute__((always_inline))
26 #elif defined(_MSC_VER)
27 # define FORCE_INLINE_ATTR __forceinline
28 #else
29 # define FORCE_INLINE_ATTR
30 #endif
31 
37 #define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR
38 
49 #if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 8 && __GNUC__ < 5
50 # define HINT_INLINE static INLINE_KEYWORD
51 #else
52 # define HINT_INLINE static INLINE_KEYWORD FORCE_INLINE_ATTR
53 #endif
54 
55 /* force no inlining */
56 #ifdef _MSC_VER
57 # define FORCE_NOINLINE static __declspec(noinline)
58 #else
59 # ifdef __GNUC__
60 # define FORCE_NOINLINE static __attribute__((__noinline__))
61 # else
62 # define FORCE_NOINLINE static
63 # endif
64 #endif
65 
66 /* target attribute */
67 #ifndef __has_attribute
68  #define __has_attribute(x) 0 /* Compatibility with non-clang compilers. */
69 #endif
70 #if defined(__GNUC__)
71 # define TARGET_ATTRIBUTE(target) __attribute__((__target__(target)))
72 #else
73 # define TARGET_ATTRIBUTE(target)
74 #endif
75 
76 /* Enable runtime BMI2 dispatch based on the CPU.
77  * Enabled for clang & gcc >=4.8 on x86 when BMI2 isn't enabled by default.
78  */
79 #ifndef DYNAMIC_BMI2
80  #if ((defined(__clang__) && __has_attribute(__target__)) \
81  || (defined(__GNUC__) \
82  && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))) \
83  && (defined(__x86_64__) || defined(_M_X86)) \
84  && !defined(__BMI2__)
85  # define DYNAMIC_BMI2 1
86  #else
87  # define DYNAMIC_BMI2 0
88  #endif
89 #endif
90 
91 /* prefetch
92  * can be disabled, by declaring NO_PREFETCH macro
93  * All prefetch invocations use a single default locality 2,
94  * generating instruction prefetcht1,
95  * which, according to Intel, means "load data into L2 cache".
96  * This is a good enough "middle ground" for the time being,
97  * though in theory, it would be better to specialize locality depending on data being prefetched.
98  * Tests could not determine any sensible difference based on locality value. */
99 #if defined(NO_PREFETCH)
100 # define PREFETCH(ptr) (void)(ptr) /* disabled */
101 #else
102 # if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86)) /* _mm_prefetch() is not defined outside of x86/x64 */
103 # include <mmintrin.h> /* https://msdn.microsoft.com/fr-fr/library/84szxsww(v=vs.90).aspx */
104 # define PREFETCH(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T1)
105 # elif defined(__GNUC__) && ( (__GNUC__ >= 4) || ( (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) ) )
106 # define PREFETCH(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 2 /* locality */)
107 # else
108 # define PREFETCH(ptr) (void)(ptr) /* disabled */
109 # endif
110 #endif /* NO_PREFETCH */
111 
112 #define CACHELINE_SIZE 64
113 
114 #define PREFETCH_AREA(p, s) { \
115  const char* const _ptr = (const char*)(p); \
116  size_t const _size = (size_t)(s); \
117  size_t _pos; \
118  for (_pos=0; _pos<_size; _pos+=CACHELINE_SIZE) { \
119  PREFETCH(_ptr + _pos); \
120  } \
121 }
122 
123 /* disable warnings */
124 #ifdef _MSC_VER /* Visual Studio */
125 # include <intrin.h> /* For Visual 2005 */
126 # pragma warning(disable : 4100) /* disable: C4100: unreferenced formal parameter */
127 # pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */
128 # pragma warning(disable : 4204) /* disable: C4204: non-constant aggregate initializer */
129 # pragma warning(disable : 4214) /* disable: C4214: non-int bitfields */
130 # pragma warning(disable : 4324) /* disable: C4324: padded structure */
131 #endif
132 
133 #endif /* ZSTD_COMPILER_H */