summaryrefslogtreecommitdiffstats
path: root/include/iprt/assertcompile.h
blob: c57c7da847a6baa731e7c337f3c943788f605b7a (plain)
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
/** @file
 * IPRT - Compile Time Assertions.
 */

/*
 * Copyright (C) 2006-2020 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
 * VirtualBox OSE distribution, in which case the provisions of the
 * CDDL are applicable instead of those of the GPL.
 *
 * You may elect to license modified versions of this file under the
 * terms and conditions of either the GPL or the CDDL or both.
 */

#ifndef IPRT_INCLUDED_assertcompile_h
#define IPRT_INCLUDED_assertcompile_h
#ifndef RT_WITHOUT_PRAGMA_ONCE
# pragma once
#endif

#include <iprt/cdefs.h>

/** @defgroup  grp_rt_assert_compile    Compile time assertions
 * @ingroup grp_rt
 *
 * These assertions are used to check structure sizes, member/size alignments
 * and similar compile time expressions.
 *
 * @remarks As you might have noticed, the AssertCompile macros don't follow the
 *          coding guidelines wrt to macros supposedly being all uppercase and
 *          underscored.  For various reasons they don't, and nobody has
 *          complained yet.
 *
 * @{
 */

/**
 * RTASSERTTYPE is the type the AssertCompile() macro redefines.
 * It has no other function and shouldn't be used.
 * Visual C++ uses this.
 */
typedef int RTASSERTTYPE[1];

/**
 * RTASSERTVAR is the type the AssertCompile() macro redefines.
 * It has no other function and shouldn't be used.
 * GCC uses this.
 */
#ifdef __GNUC__
RT_C_DECLS_BEGIN
#endif
extern int RTASSERTVAR[1];
#ifdef __GNUC__
RT_C_DECLS_END
#endif

/** @def RTASSERT_HAVE_STATIC_ASSERT
 * Indicates that the compiler implements static_assert(expr, msg).
 */
#ifdef _MSC_VER
# if _MSC_VER >= 1600 && defined(__cplusplus)
#  define RTASSERT_HAVE_STATIC_ASSERT
# endif
#endif
#if defined(__GNUC__) && defined(__GXX_EXPERIMENTAL_CXX0X__)
# define RTASSERT_HAVE_STATIC_ASSERT
#endif
#if RT_CLANG_PREREQ(6, 0)
# if __has_feature(cxx_static_assert) || __has_feature(c_static_assert)
#  define RTASSERT_HAVE_STATIC_ASSERT
# endif
#endif
#ifdef DOXYGEN_RUNNING
# define RTASSERT_HAVE_STATIC_ASSERT
#endif

/** @def AssertCompileNS
 * Asserts that a compile-time expression is true. If it's not break the build.
 *
 * This differs from AssertCompile in that it accepts some more expressions
 * than what C++0x allows - NS = Non-standard.
 *
 * @param   expr    Expression which should be true.
 */
#ifdef __GNUC__
# define AssertCompileNS(expr)  extern int RTASSERTVAR[1] __attribute__((__unused__)), RTASSERTVAR[(expr) ? 1 : 0] __attribute__((__unused__))
#elif defined(__IBMC__) || defined(__IBMCPP__)
# define AssertCompileNS(expr)  extern int RTASSERTVAR[(expr) ? 1 : 0]
#else
# define AssertCompileNS(expr)  typedef int RTASSERTTYPE[(expr) ? 1 : 0]
#endif

/** @def AssertCompile
 * Asserts that a C++0x compile-time expression is true. If it's not break the
 * build.
 * @param   expr    Expression which should be true.
 */
#ifdef RTASSERT_HAVE_STATIC_ASSERT
# ifdef __cplusplus
#  define AssertCompile(expr)    static_assert(!!(expr), #expr)
# else
#  define AssertCompile(expr)    _Static_assert(!!(expr), #expr)
# endif
#else
# define AssertCompile(expr)    AssertCompileNS(expr)
#endif

/** @def RTASSERT_OFFSET_OF()
 * A offsetof() macro suitable for compile time assertions.
 * Both GCC v4 and VisualAge for C++ v3.08 has trouble using RT_OFFSETOF.
 */
#if defined(__GNUC__)
# if __GNUC__ >= 4
#  define RTASSERT_OFFSET_OF(a_Type, a_Member)  __builtin_offsetof(a_Type, a_Member)
# else
#  define RTASSERT_OFFSET_OF(a_Type, a_Member)  RT_OFFSETOF(a_Type, a_Member)
# endif
#elif (defined(__IBMC__) || defined(__IBMCPP__)) && defined(RT_OS_OS2)
# define RTASSERT_OFFSET_OF(a_Type, a_Member)   __offsetof(a_Type, a_Member)
#elif (defined(__WATCOMC__) && defined(__cplusplus))
# define RTASSERT_OFFSET_OF(a_Type, a_Member)   __offsetof(a_Type, a_Member)
#else
# define RTASSERT_OFFSET_OF(a_Type, a_Member)   RT_OFFSETOF(a_Type, a_Member)
#endif


/** @def AssertCompileSize
 * Asserts a size at compile.
 * @param   type    The type.
 * @param   size    The expected type size.
 */
#define AssertCompileSize(type, size) \
    AssertCompile(sizeof(type) == (size))

/** @def AssertCompileSizeAlignment
 * Asserts a size alignment at compile.
 * @param   type    The type.
 * @param   align   The size alignment to assert.
 */
#define AssertCompileSizeAlignment(type, align) \
    AssertCompile(!(sizeof(type) & ((align) - 1)))

/** @def AssertCompileMemberSize
 * Asserts a member offset alignment at compile.
 * @param   type    The type.
 * @param   member  The member.
 * @param   size    The member size to assert.
 */
#define AssertCompileMemberSize(type, member, size) \
    AssertCompile(RT_SIZEOFMEMB(type, member) == (size))

/** @def AssertCompileMemberSizeAlignment
 * Asserts a member size alignment at compile.
 * @param   type    The type.
 * @param   member  The member.
 * @param   align   The member size alignment to assert.
 */
#define AssertCompileMemberSizeAlignment(type, member, align) \
    AssertCompile(!(RT_SIZEOFMEMB(type, member) & ((align) - 1)))

/** @def AssertCompileMemberAlignment
 * Asserts a member offset alignment at compile.
 * @param   type    The type.
 * @param   member  The member.
 * @param   align   The member offset alignment to assert.
 */
#define AssertCompileMemberAlignment(type, member, align) \
    AssertCompile(!(RTASSERT_OFFSET_OF(type, member) & ((align) - 1)))

/** @def AssertCompileMemberOffset
 * Asserts an offset of a structure member at compile.
 * @param   type    The type.
 * @param   member  The member.
 * @param   off     The expected offset.
 */
#define AssertCompileMemberOffset(type, member, off) \
    AssertCompile(RTASSERT_OFFSET_OF(type, member) == (off))

/** @def AssertCompile2MemberOffsets
 * Asserts that two (sub-structure) members in union have the same offset.
 * @param   type    The type.
 * @param   member1 The first member.
 * @param   member2 The second member.
 */
#define AssertCompile2MemberOffsets(type, member1, member2) \
    AssertCompile(RTASSERT_OFFSET_OF(type, member1) == RTASSERT_OFFSET_OF(type, member2))

/** @def AssertCompileAdjacentMembers
 * Asserts that two structure members are adjacent.
 * @param   type    The type.
 * @param   member1 The first member.
 * @param   member2 The second member.
 */
#define AssertCompileAdjacentMembers(type, member1, member2) \
    AssertCompile(RTASSERT_OFFSET_OF(type, member1) + RT_SIZEOFMEMB(type, member1) == RTASSERT_OFFSET_OF(type, member2))

/** @def AssertCompileMembersAtSameOffset
 * Asserts that members of two different structures are at the same offset.
 * @param   type1   The first type.
 * @param   member1 The first member.
 * @param   type2   The second type.
 * @param   member2 The second member.
 */
#define AssertCompileMembersAtSameOffset(type1, member1, type2, member2) \
    AssertCompile(RTASSERT_OFFSET_OF(type1, member1) == RTASSERT_OFFSET_OF(type2, member2))

/** @def AssertCompileMembersSameSize
 * Asserts that members of two different structures have the same size.
 * @param   type1   The first type.
 * @param   member1 The first member.
 * @param   type2   The second type.
 * @param   member2 The second member.
 */
#define AssertCompileMembersSameSize(type1, member1, type2, member2) \
    AssertCompile(RT_SIZEOFMEMB(type1, member1) == RT_SIZEOFMEMB(type2, member2))

/** @def AssertCompileMembersSameSizeAndOffset
 * Asserts that members of two different structures have the same size and are
 * at the same offset.
 * @param   type1   The first type.
 * @param   member1 The first member.
 * @param   type2   The second type.
 * @param   member2 The second member.
 */
#define AssertCompileMembersSameSizeAndOffset(type1, member1, type2, member2) \
    AssertCompile(   RTASSERT_OFFSET_OF(type1, member1) == RTASSERT_OFFSET_OF(type2, member2) \
                  && RT_SIZEOFMEMB(type1, member1) == RT_SIZEOFMEMB(type2, member2))

/** @} */

#endif /* !IPRT_INCLUDED_assertcompile_h */