aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/compiler-clang.h
blob: 4c1a39dcb624e9918dbaed72bf0c01bd0944b2df (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_COMPILER_TYPES_H
#error "Please don't include <linux/compiler-clang.h> directly, include <linux/compiler.h> instead."
#endif

/* Compiler specific definitions for Clang compiler */

/*
 * Clang prior to 17 is being silly and considers many __cleanup() variables
 * as unused (because they are, their sole purpose is to go out of scope).
 *
 * https://github.com/llvm/llvm-project/commit/877210faa447f4cc7db87812f8ed80e398fedd61
 */
#undef __cleanup
#define __cleanup(func) __maybe_unused __attribute__((__cleanup__(func)))

/* all clang versions usable with the kernel support KASAN ABI version 5 */
#define KASAN_ABI_VERSION 5

/*
 * Note: Checking __has_feature(*_sanitizer) is only true if the feature is
 * enabled. Therefore it is not required to additionally check defined(CONFIG_*)
 * to avoid adding redundant attributes in other configurations.
 */

#if __has_feature(address_sanitizer) || __has_feature(hwaddress_sanitizer)
/* Emulate GCC's __SANITIZE_ADDRESS__ flag */
#define __SANITIZE_ADDRESS__
#define __no_sanitize_address \
		__attribute__((no_sanitize("address", "hwaddress")))
#else
#define __no_sanitize_address
#endif

#if __has_feature(thread_sanitizer)
/* emulate gcc's __SANITIZE_THREAD__ flag */
#define __SANITIZE_THREAD__
#define __no_sanitize_thread \
		__attribute__((no_sanitize("thread")))
#else
#define __no_sanitize_thread
#endif

#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP)
#define __HAVE_BUILTIN_BSWAP32__
#define __HAVE_BUILTIN_BSWAP64__
#define __HAVE_BUILTIN_BSWAP16__
#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */

#if __has_feature(undefined_behavior_sanitizer)
/* GCC does not have __SANITIZE_UNDEFINED__ */
#define __no_sanitize_undefined \
		__attribute__((no_sanitize("undefined")))
#else
#define __no_sanitize_undefined
#endif

#if __has_feature(memory_sanitizer)
#define __SANITIZE_MEMORY__
/*
 * Unlike other sanitizers, KMSAN still inserts code into functions marked with
 * no_sanitize("kernel-memory"). Using disable_sanitizer_instrumentation
 * provides the behavior consistent with other __no_sanitize_ attributes,
 * guaranteeing that __no_sanitize_memory functions remain uninstrumented.
 */
#define __no_sanitize_memory __disable_sanitizer_instrumentation

/*
 * The __no_kmsan_checks attribute ensures that a function does not produce
 * false positive reports by:
 *  - initializing all local variables and memory stores in this function;
 *  - skipping all shadow checks;
 *  - passing initialized arguments to this function's callees.
 */
#define __no_kmsan_checks __attribute__((no_sanitize("kernel-memory")))
#else
#define __no_sanitize_memory
#define __no_kmsan_checks
#endif

/*
 * Support for __has_feature(coverage_sanitizer) was added in Clang 13 together
 * with no_sanitize("coverage"). Prior versions of Clang support coverage
 * instrumentation, but cannot be queried for support by the preprocessor.
 */
#if __has_feature(coverage_sanitizer)
#define __no_sanitize_coverage __attribute__((no_sanitize("coverage")))
#else
#define __no_sanitize_coverage
#endif

#if __has_feature(shadow_call_stack)
# define __noscs	__attribute__((__no_sanitize__("shadow-call-stack")))
#endif

#if __has_feature(kcfi)
/* Disable CFI checking inside a function. */
#define __nocfi		__attribute__((__no_sanitize__("kcfi")))
#endif

/*
 * Turn individual warnings and errors on and off locally, depending
 * on version.
 */
#define __diag_clang(version, severity, s) \
	__diag_clang_ ## version(__diag_clang_ ## severity s)

/* Severity used in pragma directives */
#define __diag_clang_ignore	ignored
#define __diag_clang_warn	warning
#define __diag_clang_error	error

#define __diag_str1(s)		#s
#define __diag_str(s)		__diag_str1(s)
#define __diag(s)		_Pragma(__diag_str(clang diagnostic s))

#define __diag_clang_13(s)	__diag(s)

#define __diag_ignore_all(option, comment) \
	__diag_clang(13, ignore, option)

/*
 * clang has horrible behavior with "g" or "rm" constraints for asm
 * inputs, turning them into something worse than "m". Avoid using
 * constraints with multiple possible uses (but "ir" seems to be ok):
 *
 *	https://github.com/llvm/llvm-project/issues/20571
 */
#define ASM_INPUT_G "ir"
#define ASM_INPUT_RM "r"