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1408 | serge | 1 | #ifndef __LINUX_COMPILER_H |
2 | #error "Please don't include |
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3 | #endif |
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4 | |||
5 | /* |
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6 | * Common definitions for all gcc versions go here. |
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7 | */ |
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8 | |||
9 | |||
10 | /* Optimization barrier */ |
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11 | /* The "volatile" is due to gcc bugs */ |
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12 | #define barrier() __asm__ __volatile__("": : :"memory") |
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13 | |||
14 | /* |
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15 | * This macro obfuscates arithmetic on a variable address so that gcc |
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16 | * shouldn't recognize the original var, and make assumptions about it. |
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17 | * |
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18 | * This is needed because the C standard makes it undefined to do |
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19 | * pointer arithmetic on "objects" outside their boundaries and the |
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20 | * gcc optimizers assume this is the case. In particular they |
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21 | * assume such arithmetic does not wrap. |
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22 | * |
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23 | * A miscompilation has been observed because of this on PPC. |
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24 | * To work around it we hide the relationship of the pointer and the object |
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25 | * using this macro. |
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26 | * |
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27 | * Versions of the ppc64 compiler before 4.1 had a bug where use of |
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28 | * RELOC_HIDE could trash r30. The bug can be worked around by changing |
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29 | * the inline assembly constraint from =g to =r, in this particular |
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30 | * case either is valid. |
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31 | */ |
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32 | #define RELOC_HIDE(ptr, off) \ |
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33 | ({ unsigned long __ptr; \ |
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34 | __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \ |
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35 | (typeof(ptr)) (__ptr + (off)); }) |
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36 | |||
37 | /* &a[0] degrades to a pointer: a different type from an array */ |
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38 | #define __must_be_array(a) \ |
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39 | BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(typeof(a), typeof(&a[0]))) |
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40 | |||
41 | /* |
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42 | * Force always-inline if the user requests it so via the .config, |
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43 | * or if gcc is too old: |
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44 | */ |
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45 | #if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ |
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46 | !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4) |
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47 | # define inline inline __attribute__((always_inline)) |
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48 | # define __inline__ __inline__ __attribute__((always_inline)) |
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49 | # define __inline __inline __attribute__((always_inline)) |
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50 | #endif |
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51 | |||
52 | #define __deprecated __attribute__((deprecated)) |
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53 | #define __packed __attribute__((packed)) |
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54 | #define __weak __attribute__((weak)) |
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55 | |||
56 | /* |
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57 | * it doesn't make sense on ARM (currently the only user of __naked) to trace |
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58 | * naked functions because then mcount is called without stack and frame pointer |
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59 | * being set up and there is no chance to restore the lr register to the value |
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60 | * before mcount was called. |
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61 | */ |
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62 | #define __naked __attribute__((naked)) notrace |
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63 | |||
64 | #define __noreturn __attribute__((noreturn)) |
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65 | |||
66 | /* |
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67 | * From the GCC manual: |
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68 | * |
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69 | * Many functions have no effects except the return value and their |
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70 | * return value depends only on the parameters and/or global |
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71 | * variables. Such a function can be subject to common subexpression |
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72 | * elimination and loop optimization just as an arithmetic operator |
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73 | * would be. |
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74 | * [...] |
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75 | */ |
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76 | #define __pure __attribute__((pure)) |
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77 | #define __aligned(x) __attribute__((aligned(x))) |
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78 | #define __printf(a,b) __attribute__((format(printf,a,b))) |
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79 | #define noinline __attribute__((noinline)) |
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80 | #define __attribute_const__ __attribute__((__const__)) |
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81 | #define __maybe_unused __attribute__((unused)) |
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82 | #define __always_unused __attribute__((unused)) |
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83 | |||
84 | #define __gcc_header(x) #x |
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85 | #define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h) |
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86 | #define gcc_header(x) _gcc_header(x) |
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87 | #include gcc_header(__GNUC__)> |