Commit | Line | Data |
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94f582f8 RD |
1 | #ifndef __LINUX_COMPILER_H |
2 | #error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead." | |
3 | #endif | |
1da177e4 LT |
4 | |
5 | /* | |
6 | * Common definitions for all gcc versions go here. | |
7 | */ | |
8 | ||
9 | ||
10 | /* Optimization barrier */ | |
11 | /* The "volatile" is due to gcc bugs */ | |
12 | #define barrier() __asm__ __volatile__("": : :"memory") | |
13 | ||
c8d52465 | 14 | /* |
85c210ed AK |
15 | * This macro obfuscates arithmetic on a variable address so that gcc |
16 | * shouldn't recognize the original var, and make assumptions about it. | |
17 | * | |
18 | * This is needed because the C standard makes it undefined to do | |
19 | * pointer arithmetic on "objects" outside their boundaries and the | |
20 | * gcc optimizers assume this is the case. In particular they | |
21 | * assume such arithmetic does not wrap. | |
22 | * | |
23 | * A miscompilation has been observed because of this on PPC. | |
24 | * To work around it we hide the relationship of the pointer and the object | |
25 | * using this macro. | |
26 | * | |
c8d52465 AB |
27 | * Versions of the ppc64 compiler before 4.1 had a bug where use of |
28 | * RELOC_HIDE could trash r30. The bug can be worked around by changing | |
29 | * the inline assembly constraint from =g to =r, in this particular | |
30 | * case either is valid. | |
31 | */ | |
1da177e4 LT |
32 | #define RELOC_HIDE(ptr, off) \ |
33 | ({ unsigned long __ptr; \ | |
c8d52465 | 34 | __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \ |
1da177e4 | 35 | (typeof(ptr)) (__ptr + (off)); }) |
a1365647 | 36 | |
c5e631cf | 37 | /* &a[0] degrades to a pointer: a different type from an array */ |
ea6b101d | 38 | #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) |
a1365647 | 39 | |
60a3cdd0 | 40 | /* |
ae3a0064 IM |
41 | * Force always-inline if the user requests it so via the .config, |
42 | * or if gcc is too old: | |
60a3cdd0 | 43 | */ |
765c68bd | 44 | #if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ |
ae3a0064 | 45 | !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4) |
60a3cdd0 IM |
46 | # define inline inline __attribute__((always_inline)) |
47 | # define __inline__ __inline__ __attribute__((always_inline)) | |
48 | # define __inline __inline __attribute__((always_inline)) | |
49 | #endif | |
50 | ||
a1365647 | 51 | #define __deprecated __attribute__((deprecated)) |
82ddcb04 RD |
52 | #define __packed __attribute__((packed)) |
53 | #define __weak __attribute__((weak)) | |
446c92b2 UKK |
54 | |
55 | /* | |
56 | * it doesn't make sense on ARM (currently the only user of __naked) to trace | |
57 | * naked functions because then mcount is called without stack and frame pointer | |
58 | * being set up and there is no chance to restore the lr register to the value | |
59 | * before mcount was called. | |
9c695203 MP |
60 | * |
61 | * The asm() bodies of naked functions often depend on standard calling conventions, | |
62 | * therefore they must be noinline and noclone. GCC 4.[56] currently fail to enforce | |
63 | * this, so we must do so ourselves. See GCC PR44290. | |
446c92b2 | 64 | */ |
9c695203 | 65 | #define __naked __attribute__((naked)) noinline __noclone notrace |
446c92b2 | 66 | |
82ddcb04 | 67 | #define __noreturn __attribute__((noreturn)) |
e8c44319 RB |
68 | |
69 | /* | |
70 | * From the GCC manual: | |
71 | * | |
72 | * Many functions have no effects except the return value and their | |
73 | * return value depends only on the parameters and/or global | |
74 | * variables. Such a function can be subject to common subexpression | |
75 | * elimination and loop optimization just as an arithmetic operator | |
76 | * would be. | |
77 | * [...] | |
78 | */ | |
82ddcb04 RD |
79 | #define __pure __attribute__((pure)) |
80 | #define __aligned(x) __attribute__((aligned(x))) | |
81 | #define __printf(a,b) __attribute__((format(printf,a,b))) | |
a1365647 | 82 | #define noinline __attribute__((noinline)) |
a1365647 | 83 | #define __attribute_const__ __attribute__((__const__)) |
0d7ebbbc | 84 | #define __maybe_unused __attribute__((unused)) |
7b2a3513 | 85 | #define __always_unused __attribute__((unused)) |
f153b821 LT |
86 | |
87 | #define __gcc_header(x) #x | |
88 | #define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h) | |
89 | #define gcc_header(x) _gcc_header(x) | |
90 | #include gcc_header(__GNUC__) | |
9c695203 MP |
91 | |
92 | #if !defined(__noclone) | |
93 | #define __noclone /* not needed */ | |
94 | #endif |