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 | |