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
32/**
33 * FORCE_INLINE_TEMPLATE is used to define C "templates", which take constant
34 * parameters. They must be inlined for the compiler to elimininate the constant
35 * branches.
36 */
37#define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR
38/**
39 * HINT_INLINE is used to help the compiler generate better code. It is *not*
40 * used for "templates", so it can be tweaked based on the compilers
41 * performance.
42 *
43 * gcc-4.8 and gcc-4.9 have been shown to benefit from leaving off the
44 * always_inline attribute.
45 *
46 * clang up to 5.0.0 (trunk) benefit tremendously from the always_inline
47 * attribute.
48 */
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#if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86)) /* _mm_prefetch() is not defined outside of x86/x64 */
93# include <mmintrin.h> /* https://msdn.microsoft.com/fr-fr/library/84szxsww(v=vs.90).aspx */
94# define PREFETCH(ptr) _mm_prefetch((const char*)ptr, _MM_HINT_T0)
95#elif defined(__GNUC__)
96# define PREFETCH(ptr) __builtin_prefetch(ptr, 0, 0)
97#else
98# define PREFETCH(ptr) /* disabled */
99#endif
100
101/* disable warnings */
102#ifdef _MSC_VER /* Visual Studio */
103# include <intrin.h> /* For Visual 2005 */
104# pragma warning(disable : 4100) /* disable: C4100: unreferenced formal parameter */
105# pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */
106# pragma warning(disable : 4204) /* disable: C4204: non-constant aggregate initializer */
107# pragma warning(disable : 4214) /* disable: C4214: non-int bitfields */
108# pragma warning(disable : 4324) /* disable: C4324: padded structure */
109#endif
110
111#endif /* ZSTD_COMPILER_H */
112