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Diffstat (limited to 'include/iprt/assertcompile.h')
| -rw-r--r-- | include/iprt/assertcompile.h | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/include/iprt/assertcompile.h b/include/iprt/assertcompile.h new file mode 100644 index 00000000..dae0840d --- /dev/null +++ b/include/iprt/assertcompile.h @@ -0,0 +1,263 @@ +/** @file + * IPRT - Compile Time Assertions. + */ + +/* + * Copyright (C) 2006-2022 Oracle and/or its affiliates. + * + * This file is part of VirtualBox base platform packages, as + * available from https://www.virtualbox.org. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, in version 3 of the + * License. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <https://www.gnu.org/licenses>. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included + * in the VirtualBox 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. + * + * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 + */ + +#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 and IBM VisualAge C/C++ uses this. GCC doesn't technicaly need this + * global scope one as it declares it for each use, however things get + * complicated in C++ code where most GCC and clang versions gets upset by mixed + * "C" and "C++" versions of the symbol when using inside and outside + * RT_C_DECLS_BEGIN/END. The GCC 3.3.x and 3.4.x versions we use, OTOH will + * always complain about unused RTASSERTVAR for each AssertCompileNS use in a + * function if we declare it globally, so we don't do it for those, but we do + * for 4.x+ to prevent linkage confusion. + */ +#if !defined(__cplusplus) || !defined(__GNUC__) +extern int RTASSERTVAR[1]; +#elif RT_GNUC_PREREQ(4, 0) || defined(__clang_major__) /* Not sure when they fixed the global scoping __unused__/whatever problem. */ +RT_C_DECLS_BEGIN +extern int RTASSERTVAR[1]; +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) AssertCompileNS2(expr,RTASSERTVAR) +# define AssertCompileNS2(expr,a_VarName) extern int a_VarName[ 1 ] __attribute__((__unused__)), \ + a_VarName[(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 */ + |