xref: /linux/tools/include/nolibc/compiler.h (revision 015a99fa76650e7d6efa3e36f20c0f5b346fe9ce)
1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */
2 /*
3  * NOLIBC compiler support header
4  * Copyright (C) 2023 Thomas Weißschuh <linux@weissschuh.net>
5  */
6 #ifndef _NOLIBC_COMPILER_H
7 #define _NOLIBC_COMPILER_H
8 
9 #if defined(__has_attribute)
10 #  define __nolibc_has_attribute(attr) __has_attribute(attr)
11 #else
12 #  define __nolibc_has_attribute(attr) 0
13 #endif
14 
15 #if defined(__has_feature)
16 #  define __nolibc_has_feature(feature) __has_feature(feature)
17 #else
18 #  define __nolibc_has_feature(feature) 0
19 #endif
20 
21 #define __nolibc_aligned(alignment) __attribute__((aligned(alignment)))
22 #define __nolibc_aligned_as(type) __nolibc_aligned(__alignof__(type))
23 
24 #if __nolibc_has_attribute(naked)
25 #  define __nolibc_entrypoint __attribute__((naked))
26 #  define __nolibc_entrypoint_epilogue()
27 #else
28 #  define __nolibc_entrypoint __attribute__((optimize("Os", "omit-frame-pointer")))
29 #  define __nolibc_entrypoint_epilogue() __builtin_unreachable()
30 #endif /* __nolibc_has_attribute(naked) */
31 
32 #if defined(__SSP__) || defined(__SSP_STRONG__) || defined(__SSP_ALL__) || defined(__SSP_EXPLICIT__)
33 
34 #define _NOLIBC_STACKPROTECTOR
35 
36 #endif /* defined(__SSP__) ... */
37 
38 #if __nolibc_has_attribute(no_stack_protector)
39 #  define __no_stack_protector __attribute__((no_stack_protector))
40 #else
41 #  define __no_stack_protector __attribute__((__optimize__("-fno-stack-protector")))
42 #endif /* __nolibc_has_attribute(no_stack_protector) */
43 
44 #if __nolibc_has_attribute(fallthrough)
45 #  define __nolibc_fallthrough do { } while (0); __attribute__((fallthrough))
46 #else
47 #  define __nolibc_fallthrough do { } while (0)
48 #endif /* __nolibc_has_attribute(fallthrough) */
49 
50 #endif /* _NOLIBC_COMPILER_H */
51