/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- * vim: set ts=8 sw=4 et tw=99 ft=cpp: * * ***** BEGIN LICENSE BLOCK ***** * Version: MPL 1.1/GPL 2.0/LGPL 2.1 * * The contents of this file are subject to the Mozilla Public License Version * 1.1 (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at: * http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS IS" basis, * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License * for the specific language governing rights and limitations under the * License. * * The Original Code is Mozilla Code. * * The Initial Developer of the Original Code is * The Mozilla Foundation * Portions created by the Initial Developer are Copyright (C) 2011 * the Initial Developer. All Rights Reserved. * * Contributor(s): * Jeff Walden * * Alternatively, the contents of this file may be used under the terms of * either the GNU General Public License Version 2 or later (the "GPL"), or * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), * in which case the provisions of the GPL or the LGPL are applicable instead * of those above. If you wish to allow use of your version of this file only * under the terms of either the GPL or the LGPL, and not to allow others to * use your version of this file under the terms of the MPL, indicate your * decision by deleting the provisions above and replace them with the notice * and other provisions required by the GPL or the LGPL. If you do not delete * the provisions above, a recipient may use your version of this file under * the terms of any one of the MPL, the GPL or the LGPL. * * ***** END LICENSE BLOCK ***** */ #ifndef mozilla_Assertions_h_ #define mozilla_Assertions_h_ #include "mozilla/Types.h" /* * MOZ_STATIC_ASSERT may be used to assert a condition *at compile time*. This * can be useful when you make certain assumptions about what must hold for * optimal, or even correct, behavior. For example, you might assert that the * size of a struct is a multiple of the target architecture's word size: * * struct S { ... }; * MOZ_STATIC_ASSERT(sizeof(S) % sizeof(size_t) == 0, * "S should be a multiple of word size for efficiency"); * * This macro can be used in any location where both an extern declaration and a * typedef could be used. * * Be aware of the gcc 4.2 concerns noted further down when writing patches that * use this macro, particularly if a patch only bounces on OS X. */ #ifdef __cplusplus # if defined(__clang__) # ifndef __has_extension # define __has_extension __has_feature /* compatibility, for older versions of clang */ # endif # if __has_extension(cxx_static_assert) # define MOZ_STATIC_ASSERT(cond, reason) static_assert((cond), reason) # endif # elif defined(__GNUC__) # if (defined(__GXX_EXPERIMENTAL_CXX0X__) || __cplusplus >= 201103L) && \ (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)) # define MOZ_STATIC_ASSERT(cond, reason) static_assert((cond), #cond) # endif # elif defined(_MSC_VER) # if _MSC_VER >= 1600 /* MSVC 10 */ # define MOZ_STATIC_ASSERT(cond, reason) static_assert((cond), #cond) # endif # elif defined(__HP_aCC) # if __HP_aCC >= 62500 && defined(_HP_CXX0x_SOURCE) # define MOZ_STATIC_ASSERT(cond, reason) static_assert((cond), #cond) # endif # endif #endif #ifndef MOZ_STATIC_ASSERT # define MOZ_STATIC_ASSERT_GLUE1(x, y) x##y # define MOZ_STATIC_ASSERT_GLUE(x, y) MOZ_STATIC_ASSERT_GLUE1(x, y) # if defined(__SUNPRO_CC) /* * The Sun Studio C++ compiler is buggy when declaring, inside a function, * another extern'd function with an array argument whose length contains a * sizeof, triggering the error message "sizeof expression not accepted as * size of array parameter". This bug (6688515, not public yet) would hit * defining moz_static_assert as a function, so we always define an extern * array for Sun Studio. * * We include the line number in the symbol name in a best-effort attempt * to avoid conflicts (see below). */ # define MOZ_STATIC_ASSERT(cond, reason) \ extern char MOZ_STATIC_ASSERT_GLUE(moz_static_assert, __LINE__)[(cond) ? 1 : -1] # elif defined(__COUNTER__) /* * If there was no preferred alternative, use a compiler-agnostic version. * * Note that the non-__COUNTER__ version has a bug in C++: it can't be used * in both |extern "C"| and normal C++ in the same translation unit. (Alas * |extern "C"| isn't allowed in a function.) The only affected compiler * we really care about is gcc 4.2. For that compiler and others like it, * we include the line number in the function name to do the best we can to * avoid conflicts. These should be rare: a conflict would require use of * MOZ_STATIC_ASSERT on the same line in separate files in the same * translation unit, *and* the uses would have to be in code with * different linkage, *and* the first observed use must be in C++-linkage * code. */ # define MOZ_STATIC_ASSERT(cond, reason) \ typedef int MOZ_STATIC_ASSERT_GLUE(moz_static_assert, __COUNTER__)[(cond) ? 1 : -1] # else # define MOZ_STATIC_ASSERT(cond, reason) \ extern void MOZ_STATIC_ASSERT_GLUE(moz_static_assert, __LINE__)(int arg[(cond) ? 1 : -1]) # endif #endif #define MOZ_STATIC_ASSERT_IF(cond, expr, reason) MOZ_STATIC_ASSERT(!(cond) || (expr), reason) /* * XXX: we're cheating here in order to avoid creating object files * for mfbt /just/ to provide a function like FatalError() to be used * by MOZ_ASSERT(). (It'll happen eventually, but for just ASSERT() * it isn't worth the pain.) JS_Assert(), although unfortunately * named, is part of SpiderMonkey's stable, external API, so this * isn't quite as bad as it seems. * * Once mfbt needs object files, this unholy union with JS_Assert() * will be broken. * * JS_Assert is present even in release builds, for the benefit of applications * that build DEBUG and link against a non-DEBUG SpiderMonkey library. */ #ifdef __cplusplus extern "C" { #endif extern MFBT_API(void) JS_Assert(const char* s, const char* file, int ln); #ifdef __cplusplus } /* extern "C" */ #endif /* * MOZ_ASSERT() is a "strong" assertion of state, like libc's * assert(). * * MOZ_ASSERT(twoToThePowerOf(5) == 32); * * If a MOZ_ASSERT() fails in a debug build, the process in which it fails will * stop running in a loud and dramatic way. It has no effect in an optimized * build. This macro is designed to catch bugs during debugging, not "in the * field". */ #ifdef DEBUG # define MOZ_ASSERT(expr_) \ ((expr_) ? ((void)0) : JS_Assert(#expr_, __FILE__, __LINE__)) #else # define MOZ_ASSERT(expr_) ((void)0) #endif /* DEBUG */ /* * MOZ_ASSERT_IF(cond1, cond2) is equivalent to MOZ_ASSERT(cond2) if cond1 is * true. * * MOZ_ASSERT_IF(isPrime(num), num == 2 || isOdd(num)); * * As with MOZ_ASSERT, MOZ_ASSERT_IF has effect only in debug builds. It is * designed to catch bugs during debugging, not "in the field". */ #ifdef DEBUG # define MOZ_ASSERT_IF(cond, expr) ((cond) ? MOZ_ASSERT(expr) : ((void)0)) #else # define MOZ_ASSERT_IF(cond, expr) ((void)0) #endif /* * MOZ_NOT_REACHED(reason) indicates that the given point can't be reached * during execution: simply reaching that point in execution is a bug. It takes * as an argument an error message indicating the reason why that point should * not have been reachable. * * // ...in a language parser... * void handle(BooleanLiteralNode node) * { * if (node.isTrue()) * handleTrueLiteral(); * else if (node.isFalse()) * handleFalseLiteral(); * else * MOZ_NOT_REACHED("boolean literal that's not true or false?"); * } */ #ifdef DEBUG # define MOZ_NOT_REACHED(reason) JS_Assert(reason, __FILE__, __LINE__) #else # define MOZ_NOT_REACHED(reason) ((void)0) #endif /* * MOZ_ALWAYS_TRUE(expr) and MOZ_ALWAYS_FALSE(expr) always evaluate the provided * expression, in debug builds and in release builds both. Then, in debug * builds only, the value of the expression is asserted either true or false * using MOZ_ASSERT. */ #ifdef DEBUG # define MOZ_ALWAYS_TRUE(expr) MOZ_ASSERT((expr)) # define MOZ_ALWAYS_FALSE(expr) MOZ_ASSERT(!(expr)) #else # define MOZ_ALWAYS_TRUE(expr) ((void)(expr)) # define MOZ_ALWAYS_FALSE(expr) ((void)(expr)) #endif #endif /* mozilla_Assertions_h_ */