Linux kernel mirror (for testing)
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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."
4#endif
5
6/*
7 * Common definitions for all gcc versions go here.
8 */
9#define GCC_VERSION (__GNUC__ * 10000 \
10 + __GNUC_MINOR__ * 100 \
11 + __GNUC_PATCHLEVEL__)
12
13/* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 */
14#if GCC_VERSION < 40900
15# error Sorry, your compiler is too old - please upgrade it.
16#endif
17
18/* Optimization barrier */
19
20/* The "volatile" is due to gcc bugs */
21#define barrier() __asm__ __volatile__("": : :"memory")
22/*
23 * This version is i.e. to prevent dead stores elimination on @ptr
24 * where gcc and llvm may behave differently when otherwise using
25 * normal barrier(): while gcc behavior gets along with a normal
26 * barrier(), llvm needs an explicit input variable to be assumed
27 * clobbered. The issue is as follows: while the inline asm might
28 * access any memory it wants, the compiler could have fit all of
29 * @ptr into memory registers instead, and since @ptr never escaped
30 * from that, it proved that the inline asm wasn't touching any of
31 * it. This version works well with both compilers, i.e. we're telling
32 * the compiler that the inline asm absolutely may see the contents
33 * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495
34 */
35#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
36
37/*
38 * This macro obfuscates arithmetic on a variable address so that gcc
39 * shouldn't recognize the original var, and make assumptions about it.
40 *
41 * This is needed because the C standard makes it undefined to do
42 * pointer arithmetic on "objects" outside their boundaries and the
43 * gcc optimizers assume this is the case. In particular they
44 * assume such arithmetic does not wrap.
45 *
46 * A miscompilation has been observed because of this on PPC.
47 * To work around it we hide the relationship of the pointer and the object
48 * using this macro.
49 *
50 * Versions of the ppc64 compiler before 4.1 had a bug where use of
51 * RELOC_HIDE could trash r30. The bug can be worked around by changing
52 * the inline assembly constraint from =g to =r, in this particular
53 * case either is valid.
54 */
55#define RELOC_HIDE(ptr, off) \
56({ \
57 unsigned long __ptr; \
58 __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
59 (typeof(ptr)) (__ptr + (off)); \
60})
61
62/*
63 * A trick to suppress uninitialized variable warning without generating any
64 * code
65 */
66#define uninitialized_var(x) x = x
67
68#ifdef CONFIG_RETPOLINE
69#define __noretpoline __attribute__((__indirect_branch__("keep")))
70#endif
71
72#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
73
74#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
75
76#define __compiletime_warning(message) __attribute__((__warning__(message)))
77#define __compiletime_error(message) __attribute__((__error__(message)))
78
79#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
80#define __latent_entropy __attribute__((latent_entropy))
81#endif
82
83/*
84 * calling noreturn functions, __builtin_unreachable() and __builtin_trap()
85 * confuse the stack allocation in gcc, leading to overly large stack
86 * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
87 *
88 * Adding an empty inline assembly before it works around the problem
89 */
90#define barrier_before_unreachable() asm volatile("")
91
92/*
93 * Mark a position in code as unreachable. This can be used to
94 * suppress control flow warnings after asm blocks that transfer
95 * control elsewhere.
96 */
97#define unreachable() \
98 do { \
99 annotate_unreachable(); \
100 barrier_before_unreachable(); \
101 __builtin_unreachable(); \
102 } while (0)
103
104#if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__)
105#define __randomize_layout __attribute__((randomize_layout))
106#define __no_randomize_layout __attribute__((no_randomize_layout))
107/* This anon struct can add padding, so only enable it under randstruct. */
108#define randomized_struct_fields_start struct {
109#define randomized_struct_fields_end } __randomize_layout;
110#endif
111
112/*
113 * GCC 'asm goto' miscompiles certain code sequences:
114 *
115 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
116 *
117 * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
118 *
119 * (asm goto is automatically volatile - the naming reflects this.)
120 */
121#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
122
123/*
124 * sparse (__CHECKER__) pretends to be gcc, but can't do constant
125 * folding in __builtin_bswap*() (yet), so don't set these for it.
126 */
127#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__)
128#define __HAVE_BUILTIN_BSWAP32__
129#define __HAVE_BUILTIN_BSWAP64__
130#define __HAVE_BUILTIN_BSWAP16__
131#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */
132
133#if GCC_VERSION >= 70000
134#define KASAN_ABI_VERSION 5
135#elif GCC_VERSION >= 50000
136#define KASAN_ABI_VERSION 4
137#elif GCC_VERSION >= 40902
138#define KASAN_ABI_VERSION 3
139#endif
140
141#if __has_attribute(__no_sanitize_address__)
142#define __no_sanitize_address __attribute__((no_sanitize_address))
143#else
144#define __no_sanitize_address
145#endif
146
147#if defined(__SANITIZE_THREAD__) && __has_attribute(__no_sanitize_thread__)
148#define __no_sanitize_thread __attribute__((no_sanitize_thread))
149#else
150#define __no_sanitize_thread
151#endif
152
153#if __has_attribute(__no_sanitize_undefined__)
154#define __no_sanitize_undefined __attribute__((no_sanitize_undefined))
155#else
156#define __no_sanitize_undefined
157#endif
158
159#if GCC_VERSION >= 50100
160#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
161#endif
162
163/*
164 * Turn individual warnings and errors on and off locally, depending
165 * on version.
166 */
167#define __diag_GCC(version, severity, s) \
168 __diag_GCC_ ## version(__diag_GCC_ ## severity s)
169
170/* Severity used in pragma directives */
171#define __diag_GCC_ignore ignored
172#define __diag_GCC_warn warning
173#define __diag_GCC_error error
174
175#define __diag_str1(s) #s
176#define __diag_str(s) __diag_str1(s)
177#define __diag(s) _Pragma(__diag_str(GCC diagnostic s))
178
179#if GCC_VERSION >= 80000
180#define __diag_GCC_8(s) __diag(s)
181#else
182#define __diag_GCC_8(s)
183#endif
184
185#define __no_fgcse __attribute__((optimize("-fno-gcse")))