1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
|
// Copyright © Tavian Barnes <tavianator@tavianator.com>
// SPDX-License-Identifier: 0BSD
/**
* Configuration and feature/platform detection.
*/
#ifndef BFS_PRELUDE_H
#define BFS_PRELUDE_H
// Possible __STDC_VERSION__ values
#define C95 199409L
#define C99 199901L
#define C11 201112L
#define C17 201710L
#define C23 202311L
// Get the static_assert() definition as well as __GLIBC__
#include <assert.h>
// Get the convenience macros that became standard spellings in C23
#if __STDC_VERSION__ < C23
/** _Alignas(), _Alignof() => alignas(), alignof() */
#include <stdalign.h>
/** _Bool => bool, true, false */
#include <stdbool.h>
/**
* C23 deprecates `noreturn void` in favour of `[[noreturn]] void`, so we expose
* _noreturn instead with the other attributes.
*/
// #include <stdnoreturn.h>
/** Part of <threads.h>, but we don't use anything else from it. */
#define thread_local _Thread_local
#endif // !C23
// bfs packaging configuration
#include "config.h"
#ifndef BFS_COMMAND
# define BFS_COMMAND "bfs"
#endif
#ifndef BFS_HOMEPAGE
# define BFS_HOMEPAGE "https://tavianator.com/projects/bfs.html"
#endif
// This is a symbol instead of a literal so we don't have to rebuild everything
// when the version number changes
extern const char bfs_version[];
extern const char bfs_confflags[];
extern const char bfs_cc[];
extern const char bfs_cppflags[];
extern const char bfs_cflags[];
extern const char bfs_ldflags[];
extern const char bfs_ldlibs[];
// Feature detection
// https://clang.llvm.org/docs/LanguageExtensions.html#has-attribute
#ifndef __has_attribute
# define __has_attribute(attr) false
#endif
// https://clang.llvm.org/docs/LanguageExtensions.html#has-builtin
#ifndef __has_builtin
# define __has_builtin(builtin) false
#endif
// https://en.cppreference.com/w/c/language/attributes#Attribute_testing
#ifndef __has_c_attribute
# define __has_c_attribute(attr) false
#endif
// https://clang.llvm.org/docs/LanguageExtensions.html#has-feature-and-has-extension
#ifndef __has_feature
# define __has_feature(feat) false
#endif
// https://en.cppreference.com/w/c/preprocessor/include
#ifndef __has_include
# define __has_include(header) false
#endif
// Sanitizer macros (GCC defines these but Clang does not)
#if __has_feature(address_sanitizer) && !defined(__SANITIZE_ADDRESS__)
# define __SANITIZE_ADDRESS__ true
#endif
#if __has_feature(memory_sanitizer) && !defined(__SANITIZE_MEMORY__)
# define __SANITIZE_MEMORY__ true
#endif
#if __has_feature(thread_sanitizer) && !defined(__SANITIZE_THREAD__)
# define __SANITIZE_THREAD__ true
#endif
// Fundamental utilities
/**
* Get the length of an array.
*/
#define countof(...) (sizeof(__VA_ARGS__) / sizeof(0[__VA_ARGS__]))
/**
* False sharing/destructive interference/largest cache line size.
*/
#ifdef __GCC_DESTRUCTIVE_SIZE
# define FALSE_SHARING_SIZE __GCC_DESTRUCTIVE_SIZE
#else
# define FALSE_SHARING_SIZE 64
#endif
/**
* True sharing/constructive interference/smallest cache line size.
*/
#ifdef __GCC_CONSTRUCTIVE_SIZE
# define TRUE_SHARING_SIZE __GCC_CONSTRUCTIVE_SIZE
#else
# define TRUE_SHARING_SIZE 64
#endif
/**
* Alignment specifier that avoids false sharing.
*/
#define cache_align alignas(FALSE_SHARING_SIZE)
// Wrappers for attributes
/**
* Silence warnings about switch/case fall-throughs.
*/
#if __has_attribute(fallthrough)
# define _fallthrough __attribute__((fallthrough))
#else
# define _fallthrough ((void)0)
#endif
/**
* Silence warnings about unused declarations.
*/
#if __has_attribute(unused)
# define _maybe_unused __attribute__((unused))
#else
# define _maybe_unused
#endif
/**
* Warn if a value is unused.
*/
#if __has_attribute(warn_unused_result)
# define _nodiscard __attribute__((warn_unused_result))
#else
# define _nodiscard
#endif
/**
* Hint to avoid inlining a function.
*/
#if __has_attribute(noinline)
# define _noinline __attribute__((noinline))
#else
# define _noinline
#endif
/**
* Marks a non-returning function.
*/
#if __STDC_VERSION__ >= C23
# define _noreturn [[noreturn]]
#else
# define _noreturn _Noreturn
#endif
/**
* Hint that a function is unlikely to be called.
*/
#if __has_attribute(cold)
# define _cold _noinline __attribute__((cold))
#else
# define _cold _noinline
#endif
/**
* Adds compiler warnings for bad printf()-style function calls, if supported.
*/
#if __has_attribute(format)
# define _printf(fmt, args) __attribute__((format(printf, fmt, args)))
#else
# define _printf(fmt, args)
#endif
/**
* Annotates functions that potentially modify and return format strings.
*/
#if __has_attribute(format_arg)
# define _format_arg(arg) __attribute__((format_arg(arg)))
#else
# define _format_arg(arg)
#endif
/**
* Annotates allocator-like functions.
*/
#if __has_attribute(malloc)
# if __GNUC__ >= 11 && !__OPTIMIZE__ // malloc(deallocator) disables inlining on GCC
# define _malloc(...) _nodiscard __attribute__((malloc(__VA_ARGS__)))
# else
# define _malloc(...) _nodiscard __attribute__((malloc))
# endif
#else
# define _malloc(...) _nodiscard
#endif
/**
* Specifies that a function returns allocations with a given alignment.
*/
#if __has_attribute(alloc_align)
# define _alloc_align(param) __attribute__((alloc_align(param)))
#else
# define _alloc_align(param)
#endif
/**
* Specifies that a function returns allocations with a given size.
*/
#if __has_attribute(alloc_size)
# define _alloc_size(...) __attribute__((alloc_size(__VA_ARGS__)))
#else
# define _alloc_size(...)
#endif
/**
* Shorthand for _alloc_align() and _alloc_size().
*/
#define _aligned_alloc(align, ...) _alloc_align(align) _alloc_size(__VA_ARGS__)
/**
* Check if function multiversioning via GNU indirect functions (ifunc) is supported.
*
* Disabled on TSan due to https://github.com/google/sanitizers/issues/342.
*/
#ifndef BFS_USE_TARGET_CLONES
# if __has_attribute(target_clones) && (__GLIBC__ || __FreeBSD__) && !__SANITIZE_THREAD__
# define BFS_USE_TARGET_CLONES true
# endif
#endif
/**
* Apply the target_clones attribute, if available.
*/
#if BFS_USE_TARGET_CLONES
# define _target_clones(...) __attribute__((target_clones(__VA_ARGS__)))
#else
# define _target_clones(...)
#endif
#endif // BFS_PRELUDE_H
|
