1/*
2 * Copyright (c) Meta Platforms, Inc. and affiliates.
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 definitions 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#ifndef ZSTD_MEMORY_SANITIZER
41# if __has_feature(memory_sanitizer)
42# define ZSTD_MEMORY_SANITIZER 1
43# else
44# define ZSTD_MEMORY_SANITIZER 0
45# endif
46#endif
47
48/* detects whether we are being compiled under asan */
49#ifndef ZSTD_ADDRESS_SANITIZER
50# if __has_feature(address_sanitizer)
51# define ZSTD_ADDRESS_SANITIZER 1
52# elif defined(__SANITIZE_ADDRESS__)
53# define ZSTD_ADDRESS_SANITIZER 1
54# else
55# define ZSTD_ADDRESS_SANITIZER 0
56# endif
57#endif
58
59/* detects whether we are being compiled under dfsan */
60#ifndef ZSTD_DATAFLOW_SANITIZER
61# if __has_feature(dataflow_sanitizer)
62# define ZSTD_DATAFLOW_SANITIZER 1
63# else
64# define ZSTD_DATAFLOW_SANITIZER 0
65# endif
66#endif
67
68/* Mark the internal assembly functions as hidden */
69#ifdef __ELF__
70# define ZSTD_HIDE_ASM_FUNCTION(func) .hidden func
71#else
72# define ZSTD_HIDE_ASM_FUNCTION(func)
73#endif
74
75/* Enable runtime BMI2 dispatch based on the CPU.
76 * Enabled for clang & gcc >=4.8 on x86 when BMI2 isn't enabled by default.
77 */
78#ifndef DYNAMIC_BMI2
79 #if ((defined(__clang__) && __has_attribute(__target__)) \
80 || (defined(__GNUC__) \
81 && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))) \
82 && (defined(__x86_64__) || defined(_M_X64)) \
83 && !defined(__BMI2__)
84 # define DYNAMIC_BMI2 1
85 #else
86 # define DYNAMIC_BMI2 0
87 #endif
88#endif
89
90/**
91 * Only enable assembly for GNUC compatible compilers,
92 * because other platforms may not support GAS assembly syntax.
93 *
94 * Only enable assembly for Linux / MacOS, other platforms may
95 * work, but they haven't been tested. This could likely be
96 * extended to BSD systems.
97 *
98 * Disable assembly when MSAN is enabled, because MSAN requires
99 * 100% of code to be instrumented to work.
100 */
101#if defined(__GNUC__)
102# if defined(__linux__) || defined(__linux) || defined(__APPLE__)
103# if ZSTD_MEMORY_SANITIZER
104# define ZSTD_ASM_SUPPORTED 0
105# elif ZSTD_DATAFLOW_SANITIZER
106# define ZSTD_ASM_SUPPORTED 0
107# else
108# define ZSTD_ASM_SUPPORTED 1
109# endif
110# else
111# define ZSTD_ASM_SUPPORTED 0
112# endif
113#else
114# define ZSTD_ASM_SUPPORTED 0
115#endif
116
117/**
118 * Determines whether we should enable assembly for x86-64
119 * with BMI2.
120 *
121 * Enable if all of the following conditions hold:
122 * - ASM hasn't been explicitly disabled by defining ZSTD_DISABLE_ASM
123 * - Assembly is supported
124 * - We are compiling for x86-64 and either:
125 * - DYNAMIC_BMI2 is enabled
126 * - BMI2 is supported at compile time
127 */
128#if !defined(ZSTD_DISABLE_ASM) && \
129 ZSTD_ASM_SUPPORTED && \
130 defined(__x86_64__) && \
131 (DYNAMIC_BMI2 || defined(__BMI2__))
132# define ZSTD_ENABLE_ASM_X86_64_BMI2 1
133#else
134# define ZSTD_ENABLE_ASM_X86_64_BMI2 0
135#endif
136
137/*
138 * For x86 ELF targets, add .note.gnu.property section for Intel CET in
139 * assembly sources when CET is enabled.
140 *
141 * Additionally, any function that may be called indirectly must begin
142 * with ZSTD_CET_ENDBRANCH.
143 */
144#if defined(__ELF__) && (defined(__x86_64__) || defined(__i386__)) \
145 && defined(__has_include)
146# if __has_include(<cet.h>)
147# include <cet.h>
148# define ZSTD_CET_ENDBRANCH _CET_ENDBR
149# endif
150#endif
151
152#ifndef ZSTD_CET_ENDBRANCH
153# define ZSTD_CET_ENDBRANCH
154#endif
155
156#endif /* ZSTD_PORTABILITY_MACROS_H */
157