Blame view

include/linux/compiler-gcc.h 3.56 KB
94f582f82   Robert P. J. Day   Force erroneous i...
1
2
3
  #ifndef __LINUX_COMPILER_H
  #error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
  #endif
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
4
5
6
7
8
9
10
11
12
  
  /*
   * Common definitions for all gcc versions go here.
   */
  
  
  /* Optimization barrier */
  /* The "volatile" is due to gcc bugs */
  #define barrier() __asm__ __volatile__("": : :"memory")
c8d52465f   Anton Blanchard   [PATCH] Work arou...
13
  /*
85c210edc   Andi Kleen   compiler-gcc.h: a...
14
15
16
17
18
19
20
21
22
23
24
25
   * This macro obfuscates arithmetic on a variable address so that gcc
   * shouldn't recognize the original var, and make assumptions about it.
   *
   * This is needed because the C standard makes it undefined to do
   * pointer arithmetic on "objects" outside their boundaries and the
   * gcc optimizers assume this is the case. In particular they
   * assume such arithmetic does not wrap.
   *
   * A miscompilation has been observed because of this on PPC.
   * To work around it we hide the relationship of the pointer and the object
   * using this macro.
   *
c8d52465f   Anton Blanchard   [PATCH] Work arou...
26
27
28
29
30
   * Versions of the ppc64 compiler before 4.1 had a bug where use of
   * RELOC_HIDE could trash r30. The bug can be worked around by changing
   * the inline assembly constraint from =g to =r, in this particular
   * case either is valid.
   */
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
31
32
  #define RELOC_HIDE(ptr, off)					\
    ({ unsigned long __ptr;					\
c8d52465f   Anton Blanchard   [PATCH] Work arou...
33
      __asm__ ("" : "=r"(__ptr) : "0"(ptr));		\
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
34
      (typeof(ptr)) (__ptr + (off)); })
a13656470   Andrew Morton   [PATCH] remove gc...
35

c5e631cf6   Rusty Russell   ARRAY_SIZE: check...
36
  /* &a[0] degrades to a pointer: a different type from an array */
ea6b101d8   Rusty Russell   include/linux/com...
37
  #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
a13656470   Andrew Morton   [PATCH] remove gc...
38

60a3cdd06   Ingo Molnar   x86: add optimize...
39
  /*
ae3a0064e   Ingo Molnar   inlining: do not ...
40
41
   * Force always-inline if the user requests it so via the .config,
   * or if gcc is too old:
60a3cdd06   Ingo Molnar   x86: add optimize...
42
   */
765c68bd5   Ingo Molnar   generic: make opt...
43
  #if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
ae3a0064e   Ingo Molnar   inlining: do not ...
44
      !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
60a3cdd06   Ingo Molnar   x86: add optimize...
45
46
47
48
  # define inline		inline		__attribute__((always_inline))
  # define __inline__	__inline__	__attribute__((always_inline))
  # define __inline	__inline	__attribute__((always_inline))
  #endif
a13656470   Andrew Morton   [PATCH] remove gc...
49
  #define __deprecated			__attribute__((deprecated))
82ddcb040   Robert P. J. Day   [PATCH] extend th...
50
51
  #define __packed			__attribute__((packed))
  #define __weak				__attribute__((weak))
446c92b29   Uwe Kleine-König   [ARM] 5421/1: ftr...
52
53
54
55
56
57
  
  /*
   * it doesn't make sense on ARM (currently the only user of __naked) to trace
   * naked functions because then mcount is called without stack and frame pointer
   * being set up and there is no chance to restore the lr register to the value
   * before mcount was called.
9c695203a   Mikael Pettersson   compiler-gcc.h: g...
58
59
60
61
   *
   * The asm() bodies of naked functions often depend on standard calling conventions,
   * therefore they must be noinline and noclone.  GCC 4.[56] currently fail to enforce
   * this, so we must do so ourselves.  See GCC PR44290.
446c92b29   Uwe Kleine-König   [ARM] 5421/1: ftr...
62
   */
9c695203a   Mikael Pettersson   compiler-gcc.h: g...
63
  #define __naked				__attribute__((naked)) noinline __noclone notrace
446c92b29   Uwe Kleine-König   [ARM] 5421/1: ftr...
64

82ddcb040   Robert P. J. Day   [PATCH] extend th...
65
  #define __noreturn			__attribute__((noreturn))
e8c44319c   Ralf Baechle   Replace __attribu...
66
67
68
69
70
71
72
73
74
75
76
  
  /*
   * From the GCC manual:
   *
   * Many functions have no effects except the return value and their
   * return value depends only on the parameters and/or global
   * variables.  Such a function can be subject to common subexpression
   * elimination and loop optimization just as an arithmetic operator
   * would be.
   * [...]
   */
82ddcb040   Robert P. J. Day   [PATCH] extend th...
77
78
79
  #define __pure				__attribute__((pure))
  #define __aligned(x)			__attribute__((aligned(x)))
  #define __printf(a,b)			__attribute__((format(printf,a,b)))
a13656470   Andrew Morton   [PATCH] remove gc...
80
  #define  noinline			__attribute__((noinline))
a13656470   Andrew Morton   [PATCH] remove gc...
81
  #define __attribute_const__		__attribute__((__const__))
0d7ebbbc6   David Rientjes   compiler: introdu...
82
  #define __maybe_unused			__attribute__((unused))
7b2a35132   Li Zefan   compiler: Introdu...
83
  #define __always_unused			__attribute__((unused))
f153b8212   Linus Torvalds   Sanitize gcc vers...
84
85
86
87
88
  
  #define __gcc_header(x) #x
  #define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
  #define gcc_header(x) _gcc_header(x)
  #include gcc_header(__GNUC__)
9c695203a   Mikael Pettersson   compiler-gcc.h: g...
89
90
91
92
  
  #if !defined(__noclone)
  #define __noclone	/* not needed */
  #endif
c837fb37a   Borislav Petkov   include/linux/com...
93
94
95
96
97
98
99
100
  
  /*
   * A trick to suppress uninitialized variable warning without generating any
   * code
   */
  #define uninitialized_var(x) x = x
  
  #define __always_inline		inline __attribute__((always_inline))