tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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 */