xref: /linux/include/linux/compiler-clang.h (revision f5f4745a7f057b58c9728ee4e2c5d6d79f382fe7)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __LINUX_COMPILER_TYPES_H
3 #error "Please do not include <linux/compiler-clang.h> directly, include <linux/compiler.h> instead."
4 #endif
5 
6 /* Compiler specific definitions for Clang compiler */
7 
8 /*
9  * Clang prior to 17 is being silly and considers many __cleanup() variables
10  * as unused (because they are, their sole purpose is to go out of scope).
11  *
12  * https://github.com/llvm/llvm-project/commit/877210faa447f4cc7db87812f8ed80e398fedd61
13  */
14 #undef __cleanup
15 #define __cleanup(func) __maybe_unused __attribute__((__cleanup__(func)))
16 
17 /* all clang versions usable with the kernel support KASAN ABI version 5 */
18 #define KASAN_ABI_VERSION 5
19 
20 /*
21  * Note: Checking __has_feature(*_sanitizer) is only true if the feature is
22  * enabled. Therefore it is not required to additionally check defined(CONFIG_*)
23  * to avoid adding redundant attributes in other configurations.
24  */
25 
26 #if __has_feature(address_sanitizer) || __has_feature(hwaddress_sanitizer)
27 /* Emulate GCC's __SANITIZE_ADDRESS__ flag */
28 #define __SANITIZE_ADDRESS__
29 #define __no_sanitize_address \
30 		__attribute__((no_sanitize("address", "hwaddress")))
31 #else
32 #define __no_sanitize_address
33 #endif
34 
35 #if __has_feature(thread_sanitizer)
36 /* emulate gcc's __SANITIZE_THREAD__ flag */
37 #define __SANITIZE_THREAD__
38 #define __no_sanitize_thread \
39 		__attribute__((no_sanitize("thread")))
40 #else
41 #define __no_sanitize_thread
42 #endif
43 
44 #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP)
45 #define __HAVE_BUILTIN_BSWAP32__
46 #define __HAVE_BUILTIN_BSWAP64__
47 #define __HAVE_BUILTIN_BSWAP16__
48 #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
49 
50 #if __has_feature(undefined_behavior_sanitizer)
51 /* GCC does not have __SANITIZE_UNDEFINED__ */
52 #define __no_sanitize_undefined \
53 		__attribute__((no_sanitize("undefined")))
54 #else
55 #define __no_sanitize_undefined
56 #endif
57 
58 #if __has_feature(memory_sanitizer)
59 #define __SANITIZE_MEMORY__
60 /*
61  * Unlike other sanitizers, KMSAN still inserts code into functions marked with
62  * no_sanitize("kernel-memory"). Using disable_sanitizer_instrumentation
63  * provides the behavior consistent with other __no_sanitize_ attributes,
64  * guaranteeing that __no_sanitize_memory functions remain uninstrumented.
65  */
66 #define __no_sanitize_memory __disable_sanitizer_instrumentation
67 
68 /*
69  * The __no_kmsan_checks attribute ensures that a function does not produce
70  * false positive reports by:
71  *  - initializing all local variables and memory stores in this function;
72  *  - skipping all shadow checks;
73  *  - passing initialized arguments to this function's callees.
74  */
75 #define __no_kmsan_checks __attribute__((no_sanitize("kernel-memory")))
76 #else
77 #define __no_sanitize_memory
78 #define __no_kmsan_checks
79 #endif
80 
81 /*
82  * Support for __has_feature(coverage_sanitizer) was added in Clang 13 together
83  * with no_sanitize("coverage"). Prior versions of Clang support coverage
84  * instrumentation, but cannot be queried for support by the preprocessor.
85  */
86 #if __has_feature(coverage_sanitizer)
87 #define __no_sanitize_coverage __attribute__((no_sanitize("coverage")))
88 #else
89 #define __no_sanitize_coverage
90 #endif
91 
92 #if __has_feature(shadow_call_stack)
93 # define __noscs	__attribute__((__no_sanitize__("shadow-call-stack")))
94 #endif
95 
96 #if __has_feature(kcfi)
97 /* Disable CFI checking inside a function. */
98 #define __nocfi		__attribute__((__no_sanitize__("kcfi")))
99 #endif
100 
101 /*
102  * Turn individual warnings and errors on and off locally, depending
103  * on version.
104  */
105 #define __diag_clang(version, severity, s) \
106 	__diag_clang_ ## version(__diag_clang_ ## severity s)
107 
108 /* Severity used in pragma directives */
109 #define __diag_clang_ignore	ignored
110 #define __diag_clang_warn	warning
111 #define __diag_clang_error	error
112 
113 #define __diag_str1(s)		#s
114 #define __diag_str(s)		__diag_str1(s)
115 #define __diag(s)		_Pragma(__diag_str(clang diagnostic s))
116 
117 #define __diag_clang_13(s)	__diag(s)
118 
119 #define __diag_ignore_all(option, comment) \
120 	__diag_clang(13, ignore, option)
121 
122 /*
123  * clang has horrible behavior with "g" or "rm" constraints for asm
124  * inputs, turning them into something worse than "m". Avoid using
125  * constraints with multiple possible uses (but "ir" seems to be ok):
126  *
127  *	https://github.com/llvm/llvm-project/issues/20571
128  */
129 #define ASM_INPUT_G "ir"
130 #define ASM_INPUT_RM "r"
131