1/*
2 * Copyright (c) 2008-2016 Apple Inc. All rights reserved.
3 *
4 * @APPLE_APACHE_LICENSE_HEADER_START@
5 *
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 *
18 * @APPLE_APACHE_LICENSE_HEADER_END@
19 */
20
21#ifndef __OS_BASE__
22#define __OS_BASE__
23
24#include <sys/cdefs.h>
25
26#ifndef __has_builtin
27#define __has_builtin(x) 0
28#endif
29#ifndef __has_include
30#define __has_include(x) 0
31#endif
32#ifndef __has_feature
33#define __has_feature(x) 0
34#endif
35#ifndef __has_attribute
36#define __has_attribute(x) 0
37#endif
38#ifndef __has_extension
39#define __has_extension(x) 0
40#endif
41
42#undef OS_INLINE // <sys/_types/_os_inline.h>
43#if __GNUC__
44#define OS_NORETURN __attribute__((__noreturn__))
45#define OS_NOTHROW __attribute__((__nothrow__))
46#define OS_NONNULL1 __attribute__((__nonnull__(1)))
47#define OS_NONNULL2 __attribute__((__nonnull__(2)))
48#define OS_NONNULL3 __attribute__((__nonnull__(3)))
49#define OS_NONNULL4 __attribute__((__nonnull__(4)))
50#define OS_NONNULL5 __attribute__((__nonnull__(5)))
51#define OS_NONNULL6 __attribute__((__nonnull__(6)))
52#define OS_NONNULL7 __attribute__((__nonnull__(7)))
53#define OS_NONNULL8 __attribute__((__nonnull__(8)))
54#define OS_NONNULL9 __attribute__((__nonnull__(9)))
55#define OS_NONNULL10 __attribute__((__nonnull__(10)))
56#define OS_NONNULL11 __attribute__((__nonnull__(11)))
57#define OS_NONNULL12 __attribute__((__nonnull__(12)))
58#define OS_NONNULL13 __attribute__((__nonnull__(13)))
59#define OS_NONNULL14 __attribute__((__nonnull__(14)))
60#define OS_NONNULL15 __attribute__((__nonnull__(15)))
61#define OS_NONNULL_ALL __attribute__((__nonnull__))
62#define OS_SENTINEL __attribute__((__sentinel__))
63#define OS_PURE __attribute__((__pure__))
64#define OS_CONST __attribute__((__const__))
65#define OS_WARN_RESULT __attribute__((__warn_unused_result__))
66#define OS_MALLOC __attribute__((__malloc__))
67#define OS_USED __attribute__((__used__))
68#define OS_UNUSED __attribute__((__unused__))
69#define OS_COLD __attribute__((__cold__))
70#define OS_WEAK __attribute__((__weak__))
71#define OS_WEAK_IMPORT __attribute__((__weak_import__))
72#define OS_NOINLINE __attribute__((__noinline__))
73#define OS_ALWAYS_INLINE __attribute__((__always_inline__))
74#define OS_TRANSPARENT_UNION __attribute__((__transparent_union__))
75#define OS_ALIGNED(n) __attribute__((__aligned__((n))))
76#define OS_FORMAT_PRINTF(x,y) __attribute__((__format__(printf,x,y)))
77#define OS_EXPORT extern __attribute__((__visibility__("default")))
78#define OS_INLINE static __inline__
79#define OS_EXPECT(x, v) __builtin_expect((x), (v))
80#else
81#define OS_NORETURN
82#define OS_NOTHROW
83#define OS_NONNULL1
84#define OS_NONNULL2
85#define OS_NONNULL3
86#define OS_NONNULL4
87#define OS_NONNULL5
88#define OS_NONNULL6
89#define OS_NONNULL7
90#define OS_NONNULL8
91#define OS_NONNULL9
92#define OS_NONNULL10
93#define OS_NONNULL11
94#define OS_NONNULL12
95#define OS_NONNULL13
96#define OS_NONNULL14
97#define OS_NONNULL15
98#define OS_NONNULL_ALL
99#define OS_SENTINEL
100#define OS_PURE
101#define OS_CONST
102#define OS_WARN_RESULT
103#define OS_MALLOC
104#define OS_USED
105#define OS_UNUSED
106#define OS_COLD
107#define OS_WEAK
108#define OS_WEAK_IMPORT
109#define OS_NOINLINE
110#define OS_ALWAYS_INLINE
111#define OS_TRANSPARENT_UNION
112#define OS_ALIGNED(n)
113#define OS_FORMAT_PRINTF(x,y)
114#define OS_EXPORT extern
115#define OS_INLINE static inline
116#define OS_EXPECT(x, v) (x)
117#endif
118
119#if __has_attribute(noescape)
120#define OS_NOESCAPE __attribute__((__noescape__))
121#else
122#define OS_NOESCAPE
123#endif
124
125#if __has_feature(assume_nonnull)
126#define OS_ASSUME_NONNULL_BEGIN _Pragma("clang assume_nonnull begin")
127#define OS_ASSUME_NONNULL_END _Pragma("clang assume_nonnull end")
128#else
129#define OS_ASSUME_NONNULL_BEGIN
130#define OS_ASSUME_NONNULL_END
131#endif
132
133#if __has_builtin(__builtin_assume)
134#define OS_COMPILER_CAN_ASSUME(expr) __builtin_assume(expr)
135#else
136#define OS_COMPILER_CAN_ASSUME(expr) ((void)(expr))
137#endif
138
139#if __has_extension(attribute_overloadable)
140#define OS_OVERLOADABLE __attribute__((__overloadable__))
141#else
142#define OS_OVERLOADABLE
143#endif
144
145#if __has_feature(objc_fixed_enum) || __has_extension(cxx_strong_enums)
146#define OS_ENUM(_name, _type, ...) \
147 typedef enum : _type { __VA_ARGS__ } _name##_t
148#else
149#define OS_ENUM(_name, _type, ...) \
150 enum { __VA_ARGS__ }; typedef _type _name##_t
151#endif
152
153#if __has_feature(attribute_availability_swift)
154// equivalent to __SWIFT_UNAVAILABLE from Availability.h
155#define OS_SWIFT_UNAVAILABLE(_msg) \
156 __attribute__((__availability__(swift, unavailable, message=_msg)))
157#else
158#define OS_SWIFT_UNAVAILABLE(_msg)
159#endif
160
161#if __has_attribute(swift_private)
162# define OS_REFINED_FOR_SWIFT __attribute__((__swift_private__))
163#else
164# define OS_REFINED_FOR_SWIFT
165#endif
166
167#if __has_attribute(swift_name)
168# define OS_SWIFT_NAME(_name) __attribute__((__swift_name__(#_name)))
169#else
170# define OS_SWIFT_NAME(_name)
171#endif
172
173#define __OS_STRINGIFY(s) #s
174#define OS_STRINGIFY(s) __OS_STRINGIFY(s)
175#define __OS_CONCAT(x, y) x ## y
176#define OS_CONCAT(x, y) __OS_CONCAT(x, y)
177
178#ifdef __GNUC__
179#define os_prevent_tail_call_optimization() __asm__("")
180#define os_is_compile_time_constant(expr) __builtin_constant_p(expr)
181#define os_compiler_barrier() __asm__ __volatile__("" ::: "memory")
182#else
183#define os_prevent_tail_call_optimization() do { } while (0)
184#define os_is_compile_time_constant(expr) 0
185#define os_compiler_barrier() do { } while (0)
186#endif
187
188#if __has_attribute(not_tail_called)
189#define OS_NOT_TAIL_CALLED __attribute__((__not_tail_called__))
190#else
191#define OS_NOT_TAIL_CALLED
192#endif
193
194typedef void (*os_function_t)(void *_Nullable);
195
196#ifdef __BLOCKS__
197/*!
198 * @typedef os_block_t
199 *
200 * @abstract
201 * Generic type for a block taking no arguments and returning no value.
202 *
203 * @discussion
204 * When not building with Objective-C ARC, a block object allocated on or
205 * copied to the heap must be released with a -[release] message or the
206 * Block_release() function.
207 *
208 * The declaration of a block literal allocates storage on the stack.
209 * Therefore, this is an invalid construct:
210 * <code>
211 * os_block_t block;
212 * if (x) {
213 * block = ^{ printf("true\n"); };
214 * } else {
215 * block = ^{ printf("false\n"); };
216 * }
217 * block(); // unsafe!!!
218 * </code>
219 *
220 * What is happening behind the scenes:
221 * <code>
222 * if (x) {
223 * struct Block __tmp_1 = ...; // setup details
224 * block = &__tmp_1;
225 * } else {
226 * struct Block __tmp_2 = ...; // setup details
227 * block = &__tmp_2;
228 * }
229 * </code>
230 *
231 * As the example demonstrates, the address of a stack variable is escaping the
232 * scope in which it is allocated. That is a classic C bug.
233 *
234 * Instead, the block literal must be copied to the heap with the Block_copy()
235 * function or by sending it a -[copy] message.
236 */
237typedef void (^os_block_t)(void);
238#endif
239
240#endif // __OS_BASE__
241