1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __LINUX_COMPILER_TYPES_H
3 #error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
7 * Common definitions for all gcc versions go here.
9 #define GCC_VERSION (__GNUC__ * 10000 \
10 + __GNUC_MINOR__ * 100 \
11 + __GNUC_PATCHLEVEL__)
13 #if GCC_VERSION < 40600
14 # error Sorry, your compiler is too old - please upgrade it.
17 /* Optimization barrier */
19 /* The "volatile" is due to gcc bugs */
20 #define barrier() __asm__ __volatile__("": : :"memory")
22 * This version is i.e. to prevent dead stores elimination on @ptr
23 * where gcc and llvm may behave differently when otherwise using
24 * normal barrier(): while gcc behavior gets along with a normal
25 * barrier(), llvm needs an explicit input variable to be assumed
26 * clobbered. The issue is as follows: while the inline asm might
27 * access any memory it wants, the compiler could have fit all of
28 * @ptr into memory registers instead, and since @ptr never escaped
29 * from that, it proved that the inline asm wasn't touching any of
30 * it. This version works well with both compilers, i.e. we're telling
31 * the compiler that the inline asm absolutely may see the contents
32 * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495
34 #define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
37 * This macro obfuscates arithmetic on a variable address so that gcc
38 * shouldn't recognize the original var, and make assumptions about it.
40 * This is needed because the C standard makes it undefined to do
41 * pointer arithmetic on "objects" outside their boundaries and the
42 * gcc optimizers assume this is the case. In particular they
43 * assume such arithmetic does not wrap.
45 * A miscompilation has been observed because of this on PPC.
46 * To work around it we hide the relationship of the pointer and the object
49 * Versions of the ppc64 compiler before 4.1 had a bug where use of
50 * RELOC_HIDE could trash r30. The bug can be worked around by changing
51 * the inline assembly constraint from =g to =r, in this particular
52 * case either is valid.
54 #define RELOC_HIDE(ptr, off) \
56 unsigned long __ptr; \
57 __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
58 (typeof(ptr)) (__ptr + (off)); \
61 /* Make the optimizer believe the variable can be manipulated arbitrarily. */
62 #define OPTIMIZER_HIDE_VAR(var) \
63 __asm__ ("" : "=r" (var) : "0" (var))
66 * A trick to suppress uninitialized variable warning without generating any
69 #define uninitialized_var(x) x = x
72 #define __noretpoline __attribute__((__indirect_branch__("keep")))
75 #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
77 #define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
79 #define __compiletime_warning(message) __attribute__((__warning__(message)))
80 #define __compiletime_error(message) __attribute__((__error__(message)))
82 #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
83 #define __latent_entropy __attribute__((latent_entropy))
87 * calling noreturn functions, __builtin_unreachable() and __builtin_trap()
88 * confuse the stack allocation in gcc, leading to overly large stack
89 * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
91 * Adding an empty inline assembly before it works around the problem
93 #define barrier_before_unreachable() asm volatile("")
96 * Mark a position in code as unreachable. This can be used to
97 * suppress control flow warnings after asm blocks that transfer
100 #define unreachable() \
102 annotate_unreachable(); \
103 barrier_before_unreachable(); \
104 __builtin_unreachable(); \
107 #if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__)
108 #define __randomize_layout __attribute__((randomize_layout))
109 #define __no_randomize_layout __attribute__((no_randomize_layout))
110 /* This anon struct can add padding, so only enable it under randstruct. */
111 #define randomized_struct_fields_start struct {
112 #define randomized_struct_fields_end } __randomize_layout;
116 * GCC 'asm goto' miscompiles certain code sequences:
118 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
120 * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
122 * (asm goto is automatically volatile - the naming reflects this.)
124 #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
127 * sparse (__CHECKER__) pretends to be gcc, but can't do constant
128 * folding in __builtin_bswap*() (yet), so don't set these for it.
130 #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__)
131 #define __HAVE_BUILTIN_BSWAP32__
132 #define __HAVE_BUILTIN_BSWAP64__
133 #if GCC_VERSION >= 40800
134 #define __HAVE_BUILTIN_BSWAP16__
136 #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */
138 #if GCC_VERSION >= 70000
139 #define KASAN_ABI_VERSION 5
140 #elif GCC_VERSION >= 50000
141 #define KASAN_ABI_VERSION 4
142 #elif GCC_VERSION >= 40902
143 #define KASAN_ABI_VERSION 3
146 #if __has_attribute(__no_sanitize_address__)
147 #define __no_sanitize_address __attribute__((no_sanitize_address))
149 #define __no_sanitize_address
152 #if GCC_VERSION >= 50100
153 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
157 * Turn individual warnings and errors on and off locally, depending
160 #define __diag_GCC(version, severity, s) \
161 __diag_GCC_ ## version(__diag_GCC_ ## severity s)
163 /* Severity used in pragma directives */
164 #define __diag_GCC_ignore ignored
165 #define __diag_GCC_warn warning
166 #define __diag_GCC_error error
168 #define __diag_str1(s) #s
169 #define __diag_str(s) __diag_str1(s)
170 #define __diag(s) _Pragma(__diag_str(GCC diagnostic s))
172 #if GCC_VERSION >= 80000
173 #define __diag_GCC_8(s) __diag(s)
175 #define __diag_GCC_8(s)