1/*
2 * Copyright (c) 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_PORTABILITY_MACROS_H
12#define ZSTD_PORTABILITY_MACROS_H
13
14/*
15 * This header file contains macro defintions to support portability.
16 * This header is shared between C and ASM code, so it MUST only
17 * contain macro definitions. It MUST not contain any C code.
18 *
19 * This header ONLY defines macros to detect platforms/feature support.
20 *
21 */
22
23
24/* compat. with non-clang compilers */
25#ifndef __has_attribute
26  #define __has_attribute(x) 0
27#endif
28
29/* compat. with non-clang compilers */
30#ifndef __has_builtin
31#  define __has_builtin(x) 0
32#endif
33
34/* compat. with non-clang compilers */
35#ifndef __has_feature
36#  define __has_feature(x) 0
37#endif
38
39/* detects whether we are being compiled under msan */
40
41/* detects whether we are being compiled under asan */
42
43/* detects whether we are being compiled under dfsan */
44
45/* Mark the internal assembly functions as hidden  */
46#ifdef __ELF__
47# define ZSTD_HIDE_ASM_FUNCTION(func) .hidden func
48#else
49# define ZSTD_HIDE_ASM_FUNCTION(func)
50#endif
51
52/* Enable runtime BMI2 dispatch based on the CPU.
53 * Enabled for clang & gcc >=4.8 on x86 when BMI2 isn't enabled by default.
54 */
55#ifndef DYNAMIC_BMI2
56  #if ((defined(__clang__) && __has_attribute(__target__)) \
57      || (defined(__GNUC__) \
58          && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))) \
59      && (defined(__x86_64__) || defined(_M_X64)) \
60      && !defined(__BMI2__)
61  #  define DYNAMIC_BMI2 1
62  #else
63  #  define DYNAMIC_BMI2 0
64  #endif
65#endif
66
67/*
68 * Only enable assembly for GNUC comptabile compilers,
69 * because other platforms may not support GAS assembly syntax.
70 *
71 * Only enable assembly for Linux / MacOS, other platforms may
72 * work, but they haven't been tested. This could likely be
73 * extended to BSD systems.
74 *
75 * Disable assembly when MSAN is enabled, because MSAN requires
76 * 100% of code to be instrumented to work.
77 */
78#define ZSTD_ASM_SUPPORTED 1
79
80/*
81 * Determines whether we should enable assembly for x86-64
82 * with BMI2.
83 *
84 * Enable if all of the following conditions hold:
85 * - ASM hasn't been explicitly disabled by defining ZSTD_DISABLE_ASM
86 * - Assembly is supported
87 * - We are compiling for x86-64 and either:
88 *   - DYNAMIC_BMI2 is enabled
89 *   - BMI2 is supported at compile time
90 */
91#define ZSTD_ENABLE_ASM_X86_64_BMI2 0
92
93#endif /* ZSTD_PORTABILITY_MACROS_H */
94