| /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
| /* This Source Code Form is subject to the terms of the Mozilla Public |
| * License, v. 2.0. If a copy of the MPL was not distributed with this |
| * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| |
| /* Implementations of runtime and static assertion macros for C and C++. */ |
| |
| #ifndef mozilla_Assertions_h_ |
| #define mozilla_Assertions_h_ |
| |
| #include "mozilla/Attributes.h" |
| #include "mozilla/Compiler.h" |
| #include "mozilla/Likely.h" |
| |
| #include <stddef.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| |
| #if defined(STARBOARD) |
| #include "starboard/configuration.h" |
| #include "starboard/system.h" |
| #endif |
| |
| #if defined(STARBOARD) |
| // No includes. |
| #elif defined(WIN32) |
| /* |
| * TerminateProcess and GetCurrentProcess are defined in <winbase.h>, which |
| * further depends on <windef.h>. We hardcode these few definitions manually |
| * because those headers clutter the global namespace with a significant |
| * number of undesired macros and symbols. |
| */ |
| # ifdef __cplusplus |
| extern "C" { |
| # endif |
| __declspec(dllimport) int __stdcall |
| TerminateProcess(void* hProcess, unsigned int uExitCode); |
| __declspec(dllimport) void* __stdcall GetCurrentProcess(void); |
| # ifdef __cplusplus |
| } |
| # endif |
| #else |
| # include <signal.h> |
| #endif |
| #ifdef ANDROID |
| # include <android/log.h> |
| #endif |
| |
| /* |
| * 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(STARBOARD) |
| /* Starboard's will be defined below, since we'll use the GLUE macros. */ |
| # elif 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) |
| # define MOZ_STATIC_ASSERT(cond, reason) static_assert((cond), reason) |
| # endif |
| # elif defined(_MSC_VER) |
| # if _MSC_VER >= 1600 /* MSVC 10 */ |
| # define MOZ_STATIC_ASSERT(cond, reason) static_assert((cond), reason) |
| # endif |
| # elif defined(__HP_aCC) |
| # if __HP_aCC >= 62500 && defined(_HP_CXX0x_SOURCE) |
| # define MOZ_STATIC_ASSERT(cond, reason) static_assert((cond), reason) |
| # endif |
| # endif |
| #endif |
| #ifndef MOZ_STATIC_ASSERT |
| /* |
| * Some of the definitions below create an otherwise-unused typedef. This |
| * triggers compiler warnings with some versions of gcc, so mark the typedefs |
| * as permissibly-unused to disable the warnings. |
| */ |
| # if defined(__GNUC__) |
| # define MOZ_STATIC_ASSERT_UNUSED_ATTRIBUTE __attribute__((unused)) |
| # else |
| # define MOZ_STATIC_ASSERT_UNUSED_ATTRIBUTE /* nothing */ |
| # endif |
| # define MOZ_STATIC_ASSERT_GLUE1(x, y) x##y |
| # define MOZ_STATIC_ASSERT_GLUE(x, y) MOZ_STATIC_ASSERT_GLUE1(x, y) |
| # if defined(STARBOARD) |
| # define MOZ_STATIC_ASSERT(cond, reason) SB_COMPILE_ASSERT((cond), MOZ_STATIC_ASSERT_GLUE(moz_static_assert, __LINE__)) |
| # elif 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] MOZ_STATIC_ASSERT_UNUSED_ATTRIBUTE |
| # else |
| # define MOZ_STATIC_ASSERT(cond, reason) \ |
| extern void MOZ_STATIC_ASSERT_GLUE(moz_static_assert, __LINE__)(int arg[(cond) ? 1 : -1]) MOZ_STATIC_ASSERT_UNUSED_ATTRIBUTE |
| # endif |
| #endif |
| |
| #define MOZ_STATIC_ASSERT_IF(cond, expr, reason) MOZ_STATIC_ASSERT(!(cond) || (expr), reason) |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /* |
| * MOZ_CRASH crashes the program, plain and simple, in a Breakpad-compatible |
| * way, in both debug and release builds. |
| * |
| * MOZ_CRASH is a good solution for "handling" failure cases when you're |
| * unwilling or unable to handle them more cleanly -- for OOM, for likely memory |
| * corruption, and so on. It's also a good solution if you need safe behavior |
| * in release builds as well as debug builds. But if the failure is one that |
| * should be debugged and fixed, MOZ_ASSERT is generally preferable. |
| */ |
| #if defined(STARBOARD) && (SB_API_VERSION >= 4) |
| # define MOZ_CRASH() \ |
| do { \ |
| *((volatile int*) NULL) = 123; \ |
| ::SbSystemBreakIntoDebugger(); \ |
| } while (0) |
| #elif defined(_MSC_VER) |
| /* |
| * On MSVC use the __debugbreak compiler intrinsic, which produces an inline |
| * (not nested in a system function) breakpoint. This distinctively invokes |
| * Breakpad without requiring system library symbols on all stack-processing |
| * machines, as a nested breakpoint would require. We use TerminateProcess |
| * with the exit code aborting would generate because we don't want to invoke |
| * atexit handlers, destructors, library unload handlers, and so on when our |
| * process might be in a compromised state. We don't use abort() because |
| * it'd cause Windows to annoyingly pop up the process error dialog multiple |
| * times. See bug 345118 and bug 426163. |
| * |
| * (Technically these are Windows requirements, not MSVC requirements. But |
| * practically you need MSVC for debugging, and we only ship builds created |
| * by MSVC, so doing it this way reduces complexity.) |
| */ |
| # ifdef __cplusplus |
| # define MOZ_CRASH() \ |
| do { \ |
| __debugbreak(); \ |
| *((volatile int*) NULL) = 123; \ |
| ::TerminateProcess(::GetCurrentProcess(), 3); \ |
| } while (0) |
| # else |
| # define MOZ_CRASH() \ |
| do { \ |
| __debugbreak(); \ |
| *((volatile int*) NULL) = 123; \ |
| TerminateProcess(GetCurrentProcess(), 3); \ |
| } while (0) |
| # endif |
| #else |
| # ifdef __cplusplus |
| # define MOZ_CRASH() \ |
| do { \ |
| *((volatile int*) NULL) = 123; \ |
| ::abort(); \ |
| } while (0) |
| # else |
| # define MOZ_CRASH() \ |
| do { \ |
| *((volatile int*) NULL) = 123; \ |
| abort(); \ |
| } while (0) |
| # endif |
| #endif |
| |
| /* |
| * Prints |s| as an assertion failure (using file and ln as the location of the |
| * assertion) to the standard debug-output channel. |
| * |
| * Usually you should use MOZ_ASSERT instead of this method. This method is |
| * primarily for internal use in this header, and only secondarily for use in |
| * implementing release-build assertions. |
| */ |
| static MOZ_ALWAYS_INLINE void |
| MOZ_ReportAssertionFailure(const char* s, const char* file, int ln) |
| { |
| #ifdef ANDROID |
| __android_log_print(ANDROID_LOG_FATAL, "MOZ_Assert", |
| "Assertion failure: %s, at %s:%d\n", s, file, ln); |
| #else |
| fprintf(stderr, "Assertion failure: %s, at %s:%d\n", s, file, ln); |
| fflush(stderr); |
| #endif |
| } |
| |
| #ifdef __cplusplus |
| } /* extern "C" */ |
| #endif |
| |
| /* |
| * MOZ_ASSERT(expr [, explanation-string]) asserts that |expr| must be truthy in |
| * debug builds. If it is, execution continues. Otherwise, an error message |
| * including the expression and the explanation-string (if provided) is printed, |
| * an attempt is made to invoke any existing debugger, and execution halts. |
| * MOZ_ASSERT is fatal: no recovery is possible. Do not assert a condition |
| * which can correctly be falsy. |
| * |
| * The optional explanation-string, if provided, must be a string literal |
| * explaining the assertion. It is intended for use with assertions whose |
| * correctness or rationale is non-obvious, and for assertions where the "real" |
| * condition being tested is best described prosaically. Don't provide an |
| * explanation if it's not actually helpful. |
| * |
| * // No explanation needed: pointer arguments often must not be NULL. |
| * MOZ_ASSERT(arg); |
| * |
| * // An explanation can be helpful to explain exactly how we know an |
| * // assertion is valid. |
| * MOZ_ASSERT(state == WAITING_FOR_RESPONSE, |
| * "given that <thingA> and <thingB>, we must have..."); |
| * |
| * // Or it might disambiguate multiple identical (save for their location) |
| * // assertions of the same expression. |
| * MOZ_ASSERT(getSlot(PRIMITIVE_THIS_SLOT).isUndefined(), |
| * "we already set [[PrimitiveThis]] for this Boolean object"); |
| * MOZ_ASSERT(getSlot(PRIMITIVE_THIS_SLOT).isUndefined(), |
| * "we already set [[PrimitiveThis]] for this String object"); |
| * |
| * MOZ_ASSERT has no effect in non-debug builds. It is designed to catch bugs |
| * *only* during debugging, not "in the field". |
| */ |
| #ifdef DEBUG |
| /* First the single-argument form. */ |
| # define MOZ_ASSERT_HELPER1(expr) \ |
| do { \ |
| if (MOZ_UNLIKELY(!(expr))) { \ |
| MOZ_ReportAssertionFailure(#expr, __FILE__, __LINE__); \ |
| MOZ_CRASH(); \ |
| } \ |
| } while (0) |
| /* Now the two-argument form. */ |
| # define MOZ_ASSERT_HELPER2(expr, explain) \ |
| do { \ |
| if (MOZ_UNLIKELY(!(expr))) { \ |
| MOZ_ReportAssertionFailure(#expr " (" explain ")", __FILE__, __LINE__); \ |
| MOZ_CRASH(); \ |
| } \ |
| } while (0) |
| /* And now, helper macrology up the wazoo. */ |
| /* |
| * Count the number of arguments passed to MOZ_ASSERT, very carefully |
| * tiptoeing around an MSVC bug where it improperly expands __VA_ARGS__ as a |
| * single token in argument lists. See these URLs for details: |
| * |
| * http://connect.microsoft.com/VisualStudio/feedback/details/380090/variadic-macro-replacement |
| * http://cplusplus.co.il/2010/07/17/variadic-macro-to-count-number-of-arguments/#comment-644 |
| */ |
| # define MOZ_COUNT_ASSERT_ARGS_IMPL2(_1, _2, count, ...) \ |
| count |
| # define MOZ_COUNT_ASSERT_ARGS_IMPL(args) \ |
| MOZ_COUNT_ASSERT_ARGS_IMPL2 args |
| # define MOZ_COUNT_ASSERT_ARGS(...) \ |
| MOZ_COUNT_ASSERT_ARGS_IMPL((__VA_ARGS__, 2, 1, 0)) |
| /* Pick the right helper macro to invoke. */ |
| # define MOZ_ASSERT_CHOOSE_HELPER2(count) MOZ_ASSERT_HELPER##count |
| # define MOZ_ASSERT_CHOOSE_HELPER1(count) MOZ_ASSERT_CHOOSE_HELPER2(count) |
| # define MOZ_ASSERT_CHOOSE_HELPER(count) MOZ_ASSERT_CHOOSE_HELPER1(count) |
| /* The actual macro. */ |
| # define MOZ_ASSERT_GLUE(x, y) x y |
| # define MOZ_ASSERT(...) \ |
| MOZ_ASSERT_GLUE(MOZ_ASSERT_CHOOSE_HELPER(MOZ_COUNT_ASSERT_ARGS(__VA_ARGS__)), \ |
| (__VA_ARGS__)) |
| #else |
| # define MOZ_ASSERT(...) do { } while(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) \ |
| do { \ |
| if (cond) \ |
| MOZ_ASSERT(expr); \ |
| } while (0) |
| #else |
| # define MOZ_ASSERT_IF(cond, expr) do { } while (0) |
| #endif |
| |
| /* |
| * MOZ_NOT_REACHED_MARKER() expands to an expression which states that it is |
| * undefined behavior for execution to reach this point. No guarantees are made |
| * about what will happen if this is reached at runtime. Most code should |
| * probably use the higher level MOZ_NOT_REACHED, which uses this when |
| * appropriate. |
| */ |
| #if defined(__clang__) |
| # define MOZ_NOT_REACHED_MARKER() __builtin_unreachable() |
| #elif defined(__GNUC__) |
| /* |
| * __builtin_unreachable() was implemented in gcc 4.5. If we don't have |
| * that, call a noreturn function; abort() will do nicely. Qualify the call |
| * in C++ in case there's another abort() visible in local scope. |
| */ |
| # if MOZ_GCC_VERSION_AT_LEAST(4, 5, 0) |
| # define MOZ_NOT_REACHED_MARKER() __builtin_unreachable() |
| # else |
| # ifdef __cplusplus |
| # define MOZ_NOT_REACHED_MARKER() ::abort() |
| # else |
| # define MOZ_NOT_REACHED_MARKER() abort() |
| # endif |
| # endif |
| #elif defined(_MSC_VER) |
| # define MOZ_NOT_REACHED_MARKER() __assume(0) |
| #else |
| # ifdef __cplusplus |
| # define MOZ_NOT_REACHED_MARKER() ::abort() |
| # else |
| # define MOZ_NOT_REACHED_MARKER() abort() |
| # endif |
| #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?"); |
| * } |
| */ |
| #if defined(DEBUG) |
| # define MOZ_NOT_REACHED(reason) \ |
| do { \ |
| MOZ_ASSERT(false, reason); \ |
| MOZ_NOT_REACHED_MARKER(); \ |
| } while (0) |
| #else |
| # define MOZ_NOT_REACHED(reason) MOZ_NOT_REACHED_MARKER() |
| #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_ */ |