xref: /linux-6.15/include/linux/compiler.h (revision 1da177e4)
1 #ifndef __LINUX_COMPILER_H
2 #define __LINUX_COMPILER_H
3 
4 #ifndef __ASSEMBLY__
5 
6 #ifdef __CHECKER__
7 # define __user		__attribute__((noderef, address_space(1)))
8 # define __kernel	/* default address space */
9 # define __safe		__attribute__((safe))
10 # define __force	__attribute__((force))
11 # define __nocast	__attribute__((nocast))
12 # define __iomem	__attribute__((noderef, address_space(2)))
13 # define __acquires(x)	__attribute__((context(0,1)))
14 # define __releases(x)	__attribute__((context(1,0)))
15 # define __acquire(x)	__context__(1)
16 # define __release(x)	__context__(-1)
17 # define __cond_lock(x)	((x) ? ({ __context__(1); 1; }) : 0)
18 extern void __chk_user_ptr(void __user *);
19 extern void __chk_io_ptr(void __iomem *);
20 #else
21 # define __user
22 # define __kernel
23 # define __safe
24 # define __force
25 # define __nocast
26 # define __iomem
27 # define __chk_user_ptr(x) (void)0
28 # define __chk_io_ptr(x) (void)0
29 # define __builtin_warning(x, y...) (1)
30 # define __acquires(x)
31 # define __releases(x)
32 # define __acquire(x) (void)0
33 # define __release(x) (void)0
34 # define __cond_lock(x) (x)
35 #endif
36 
37 #ifdef __KERNEL__
38 
39 #if __GNUC__ > 4
40 #error no compiler-gcc.h file for this gcc version
41 #elif __GNUC__ == 4
42 # include <linux/compiler-gcc4.h>
43 #elif __GNUC__ == 3
44 # include <linux/compiler-gcc3.h>
45 #elif __GNUC__ == 2
46 # include <linux/compiler-gcc2.h>
47 #else
48 # error Sorry, your compiler is too old/not recognized.
49 #endif
50 
51 /* Intel compiler defines __GNUC__. So we will overwrite implementations
52  * coming from above header files here
53  */
54 #ifdef __INTEL_COMPILER
55 # include <linux/compiler-intel.h>
56 #endif
57 
58 /*
59  * Generic compiler-dependent macros required for kernel
60  * build go below this comment. Actual compiler/compiler version
61  * specific implementations come from the above header files
62  */
63 
64 #define likely(x)	__builtin_expect(!!(x), 1)
65 #define unlikely(x)	__builtin_expect(!!(x), 0)
66 
67 /* Optimization barrier */
68 #ifndef barrier
69 # define barrier() __memory_barrier()
70 #endif
71 
72 #ifndef RELOC_HIDE
73 # define RELOC_HIDE(ptr, off)					\
74   ({ unsigned long __ptr;					\
75      __ptr = (unsigned long) (ptr);				\
76     (typeof(ptr)) (__ptr + (off)); })
77 #endif
78 
79 #endif /* __KERNEL__ */
80 
81 #endif /* __ASSEMBLY__ */
82 
83 /*
84  * Allow us to mark functions as 'deprecated' and have gcc emit a nice
85  * warning for each use, in hopes of speeding the functions removal.
86  * Usage is:
87  * 		int __deprecated foo(void)
88  */
89 #ifndef __deprecated
90 # define __deprecated		/* unimplemented */
91 #endif
92 
93 #ifndef __must_check
94 #define __must_check
95 #endif
96 
97 /*
98  * Allow us to avoid 'defined but not used' warnings on functions and data,
99  * as well as force them to be emitted to the assembly file.
100  *
101  * As of gcc 3.3, static functions that are not marked with attribute((used))
102  * may be elided from the assembly file.  As of gcc 3.3, static data not so
103  * marked will not be elided, but this may change in a future gcc version.
104  *
105  * In prior versions of gcc, such functions and data would be emitted, but
106  * would be warned about except with attribute((unused)).
107  */
108 #ifndef __attribute_used__
109 # define __attribute_used__	/* unimplemented */
110 #endif
111 
112 /*
113  * From the GCC manual:
114  *
115  * Many functions have no effects except the return value and their
116  * return value depends only on the parameters and/or global
117  * variables.  Such a function can be subject to common subexpression
118  * elimination and loop optimization just as an arithmetic operator
119  * would be.
120  * [...]
121  */
122 #ifndef __attribute_pure__
123 # define __attribute_pure__	/* unimplemented */
124 #endif
125 
126 /*
127  * From the GCC manual:
128  *
129  * Many functions do not examine any values except their arguments,
130  * and have no effects except the return value.  Basically this is
131  * just slightly more strict class than the `pure' attribute above,
132  * since function is not allowed to read global memory.
133  *
134  * Note that a function that has pointer arguments and examines the
135  * data pointed to must _not_ be declared `const'.  Likewise, a
136  * function that calls a non-`const' function usually must not be
137  * `const'.  It does not make sense for a `const' function to return
138  * `void'.
139  */
140 #ifndef __attribute_const__
141 # define __attribute_const__	/* unimplemented */
142 #endif
143 
144 #ifndef noinline
145 #define noinline
146 #endif
147 
148 #ifndef __always_inline
149 #define __always_inline inline
150 #endif
151 
152 #endif /* __LINUX_COMPILER_H */
153