mirror of
https://github.com/mozilla/gecko-dev.git
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2511b2c327
It's an annotation that is used a lot, and should be used even more, so a shorter name is better. MozReview-Commit-ID: 1VS4Dney4WX --HG-- extra : rebase_source : b26919c1b0fcb32e5339adeef5be5becae6032cf
566 lines
20 KiB
C++
566 lines
20 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* Implementations of runtime and static assertion macros for C and C++. */
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#ifndef mozilla_Assertions_h
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#define mozilla_Assertions_h
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#if defined(MOZILLA_INTERNAL_API) && defined(__cplusplus)
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#define MOZ_DUMP_ASSERTION_STACK
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#endif
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#include "mozilla/Attributes.h"
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#include "mozilla/Compiler.h"
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#include "mozilla/Likely.h"
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#include "mozilla/MacroArgs.h"
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#ifdef MOZ_DUMP_ASSERTION_STACK
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#include "nsTraceRefcnt.h"
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#endif
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#if defined(MOZ_CRASHREPORTER) && defined(MOZILLA_INTERNAL_API) && \
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!defined(MOZILLA_EXTERNAL_LINKAGE) && defined(__cplusplus)
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namespace CrashReporter {
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// This declaration is present here as well as in nsExceptionHandler.h
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// nsExceptionHandler.h is not directly included in this file as it includes
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// windows.h, which can cause problems when it is imported into some files due
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// to the number of macros defined.
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// XXX If you change this definition - also change the definition in
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// nsExceptionHandler.h
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void AnnotateMozCrashReason(const char* aReason);
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} // namespace CrashReporter
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# define MOZ_CRASH_ANNOTATE(...) CrashReporter::AnnotateMozCrashReason("" __VA_ARGS__)
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#else
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# define MOZ_CRASH_ANNOTATE(...) do { /* nothing */ } while (0)
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#endif
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#ifdef WIN32
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/*
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* TerminateProcess and GetCurrentProcess are defined in <winbase.h>, which
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* further depends on <windef.h>. We hardcode these few definitions manually
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* because those headers clutter the global namespace with a significant
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* number of undesired macros and symbols.
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*/
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# ifdef __cplusplus
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extern "C" {
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# endif
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__declspec(dllimport) int __stdcall
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TerminateProcess(void* hProcess, unsigned int uExitCode);
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__declspec(dllimport) void* __stdcall GetCurrentProcess(void);
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# ifdef __cplusplus
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}
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# endif
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#else
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# include <signal.h>
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#endif
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#ifdef ANDROID
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# include <android/log.h>
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#endif
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/*
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* MOZ_STATIC_ASSERT may be used to assert a condition *at compile time* in C.
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* In C++11, static_assert is provided by the compiler to the same effect.
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* This can be useful when you make certain assumptions about what must hold for
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* optimal, or even correct, behavior. For example, you might assert that the
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* size of a struct is a multiple of the target architecture's word size:
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*
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* struct S { ... };
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* // C
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* MOZ_STATIC_ASSERT(sizeof(S) % sizeof(size_t) == 0,
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* "S should be a multiple of word size for efficiency");
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* // C++11
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* static_assert(sizeof(S) % sizeof(size_t) == 0,
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* "S should be a multiple of word size for efficiency");
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*
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* This macro can be used in any location where both an extern declaration and a
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* typedef could be used.
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*/
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#ifndef __cplusplus
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/*
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* Some of the definitions below create an otherwise-unused typedef. This
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* triggers compiler warnings with some versions of gcc, so mark the typedefs
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* as permissibly-unused to disable the warnings.
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*/
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# if defined(__GNUC__)
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# define MOZ_STATIC_ASSERT_UNUSED_ATTRIBUTE __attribute__((unused))
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# else
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# define MOZ_STATIC_ASSERT_UNUSED_ATTRIBUTE /* nothing */
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# endif
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# define MOZ_STATIC_ASSERT_GLUE1(x, y) x##y
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# define MOZ_STATIC_ASSERT_GLUE(x, y) MOZ_STATIC_ASSERT_GLUE1(x, y)
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# if defined(__SUNPRO_CC)
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/*
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* The Sun Studio C++ compiler is buggy when declaring, inside a function,
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* another extern'd function with an array argument whose length contains a
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* sizeof, triggering the error message "sizeof expression not accepted as
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* size of array parameter". This bug (6688515, not public yet) would hit
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* defining moz_static_assert as a function, so we always define an extern
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* array for Sun Studio.
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*
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* We include the line number in the symbol name in a best-effort attempt
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* to avoid conflicts (see below).
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*/
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# define MOZ_STATIC_ASSERT(cond, reason) \
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extern char MOZ_STATIC_ASSERT_GLUE(moz_static_assert, __LINE__)[(cond) ? 1 : -1]
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# elif defined(__COUNTER__)
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/*
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* If there was no preferred alternative, use a compiler-agnostic version.
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*
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* Note that the non-__COUNTER__ version has a bug in C++: it can't be used
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* in both |extern "C"| and normal C++ in the same translation unit. (Alas
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* |extern "C"| isn't allowed in a function.) The only affected compiler
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* we really care about is gcc 4.2. For that compiler and others like it,
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* we include the line number in the function name to do the best we can to
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* avoid conflicts. These should be rare: a conflict would require use of
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* MOZ_STATIC_ASSERT on the same line in separate files in the same
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* translation unit, *and* the uses would have to be in code with
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* different linkage, *and* the first observed use must be in C++-linkage
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* code.
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*/
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# define MOZ_STATIC_ASSERT(cond, reason) \
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typedef int MOZ_STATIC_ASSERT_GLUE(moz_static_assert, __COUNTER__)[(cond) ? 1 : -1] MOZ_STATIC_ASSERT_UNUSED_ATTRIBUTE
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# else
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# define MOZ_STATIC_ASSERT(cond, reason) \
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extern void MOZ_STATIC_ASSERT_GLUE(moz_static_assert, __LINE__)(int arg[(cond) ? 1 : -1]) MOZ_STATIC_ASSERT_UNUSED_ATTRIBUTE
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# endif
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#define MOZ_STATIC_ASSERT_IF(cond, expr, reason) MOZ_STATIC_ASSERT(!(cond) || (expr), reason)
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#else
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#define MOZ_STATIC_ASSERT_IF(cond, expr, reason) static_assert(!(cond) || (expr), reason)
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#endif
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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* Prints |aStr| as an assertion failure (using aFilename and aLine as the
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* location of the assertion) to the standard debug-output channel.
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*
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* Usually you should use MOZ_ASSERT or MOZ_CRASH instead of this method. This
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* method is primarily for internal use in this header, and only secondarily
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* for use in implementing release-build assertions.
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*/
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static MOZ_COLD MOZ_ALWAYS_INLINE void
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MOZ_ReportAssertionFailure(const char* aStr, const char* aFilename, int aLine)
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MOZ_PRETEND_NORETURN_FOR_STATIC_ANALYSIS
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{
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#ifdef ANDROID
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__android_log_print(ANDROID_LOG_FATAL, "MOZ_Assert",
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"Assertion failure: %s, at %s:%d\n",
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aStr, aFilename, aLine);
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#else
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fprintf(stderr, "Assertion failure: %s, at %s:%d\n", aStr, aFilename, aLine);
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#if defined (MOZ_DUMP_ASSERTION_STACK)
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nsTraceRefcnt::WalkTheStack(stderr);
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#endif
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fflush(stderr);
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#endif
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}
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static MOZ_COLD MOZ_ALWAYS_INLINE void
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MOZ_ReportCrash(const char* aStr, const char* aFilename, int aLine)
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MOZ_PRETEND_NORETURN_FOR_STATIC_ANALYSIS
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{
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#ifdef ANDROID
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__android_log_print(ANDROID_LOG_FATAL, "MOZ_CRASH",
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"Hit MOZ_CRASH(%s) at %s:%d\n", aStr, aFilename, aLine);
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#else
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fprintf(stderr, "Hit MOZ_CRASH(%s) at %s:%d\n", aStr, aFilename, aLine);
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#if defined(MOZ_DUMP_ASSERTION_STACK)
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nsTraceRefcnt::WalkTheStack(stderr);
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#endif
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fflush(stderr);
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#endif
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}
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/**
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* MOZ_REALLY_CRASH is used in the implementation of MOZ_CRASH(). You should
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* call MOZ_CRASH instead.
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*/
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#if defined(_MSC_VER)
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/*
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* On MSVC use the __debugbreak compiler intrinsic, which produces an inline
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* (not nested in a system function) breakpoint. This distinctively invokes
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* Breakpad without requiring system library symbols on all stack-processing
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* machines, as a nested breakpoint would require.
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*
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* We use TerminateProcess with the exit code aborting would generate
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* because we don't want to invoke atexit handlers, destructors, library
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* unload handlers, and so on when our process might be in a compromised
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* state.
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*
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* We don't use abort() because it'd cause Windows to annoyingly pop up the
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* process error dialog multiple times. See bug 345118 and bug 426163.
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*
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* We follow TerminateProcess() with a call to MOZ_NoReturn() so that the
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* compiler doesn't hassle us to provide a return statement after a
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* MOZ_REALLY_CRASH() call.
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*
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* (Technically these are Windows requirements, not MSVC requirements. But
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* practically you need MSVC for debugging, and we only ship builds created
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* by MSVC, so doing it this way reduces complexity.)
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*/
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__declspec(noreturn) __inline void MOZ_NoReturn() {}
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# ifdef __cplusplus
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# define MOZ_REALLY_CRASH() \
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do { \
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::__debugbreak(); \
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*((volatile int*) NULL) = __LINE__; \
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::TerminateProcess(::GetCurrentProcess(), 3); \
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::MOZ_NoReturn(); \
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} while (0)
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# else
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# define MOZ_REALLY_CRASH() \
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do { \
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__debugbreak(); \
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*((volatile int*) NULL) = __LINE__; \
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TerminateProcess(GetCurrentProcess(), 3); \
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MOZ_NoReturn(); \
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} while (0)
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# endif
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#else
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# ifdef __cplusplus
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# define MOZ_REALLY_CRASH() \
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do { \
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*((volatile int*) NULL) = __LINE__; \
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::abort(); \
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} while (0)
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# else
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# define MOZ_REALLY_CRASH() \
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do { \
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*((volatile int*) NULL) = __LINE__; \
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abort(); \
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} while (0)
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# endif
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#endif
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/*
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* MOZ_CRASH([explanation-string]) crashes the program, plain and simple, in a
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* Breakpad-compatible way, in both debug and release builds.
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*
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* MOZ_CRASH is a good solution for "handling" failure cases when you're
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* unwilling or unable to handle them more cleanly -- for OOM, for likely memory
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* corruption, and so on. It's also a good solution if you need safe behavior
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* in release builds as well as debug builds. But if the failure is one that
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* should be debugged and fixed, MOZ_ASSERT is generally preferable.
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*
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* The optional explanation-string, if provided, must be a string literal
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* explaining why we're crashing. This argument is intended for use with
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* MOZ_CRASH() calls whose rationale is non-obvious; don't use it if it's
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* obvious why we're crashing.
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*
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* If we're a DEBUG build and we crash at a MOZ_CRASH which provides an
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* explanation-string, we print the string to stderr. Otherwise, we don't
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* print anything; this is because we want MOZ_CRASH to be 100% safe in release
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* builds, and it's hard to print to stderr safely when memory might have been
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* corrupted.
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*/
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#ifndef DEBUG
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# define MOZ_CRASH(...) \
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do { \
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MOZ_CRASH_ANNOTATE("MOZ_CRASH(" __VA_ARGS__ ")"); \
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MOZ_REALLY_CRASH(); \
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} while (0)
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#else
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# define MOZ_CRASH(...) \
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do { \
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MOZ_ReportCrash("" __VA_ARGS__, __FILE__, __LINE__); \
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MOZ_CRASH_ANNOTATE("MOZ_CRASH(" __VA_ARGS__ ")"); \
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MOZ_REALLY_CRASH(); \
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} while (0)
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#endif
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#ifdef __cplusplus
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} /* extern "C" */
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#endif
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/*
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* MOZ_ASSERT(expr [, explanation-string]) asserts that |expr| must be truthy in
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* debug builds. If it is, execution continues. Otherwise, an error message
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* including the expression and the explanation-string (if provided) is printed,
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* an attempt is made to invoke any existing debugger, and execution halts.
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* MOZ_ASSERT is fatal: no recovery is possible. Do not assert a condition
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* which can correctly be falsy.
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*
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* The optional explanation-string, if provided, must be a string literal
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* explaining the assertion. It is intended for use with assertions whose
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* correctness or rationale is non-obvious, and for assertions where the "real"
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* condition being tested is best described prosaically. Don't provide an
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* explanation if it's not actually helpful.
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*
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* // No explanation needed: pointer arguments often must not be NULL.
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* MOZ_ASSERT(arg);
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*
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* // An explanation can be helpful to explain exactly how we know an
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* // assertion is valid.
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* MOZ_ASSERT(state == WAITING_FOR_RESPONSE,
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* "given that <thingA> and <thingB>, we must have...");
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*
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* // Or it might disambiguate multiple identical (save for their location)
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* // assertions of the same expression.
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* MOZ_ASSERT(getSlot(PRIMITIVE_THIS_SLOT).isUndefined(),
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* "we already set [[PrimitiveThis]] for this Boolean object");
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* MOZ_ASSERT(getSlot(PRIMITIVE_THIS_SLOT).isUndefined(),
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* "we already set [[PrimitiveThis]] for this String object");
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*
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* MOZ_ASSERT has no effect in non-debug builds. It is designed to catch bugs
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* *only* during debugging, not "in the field". If you want the latter, use
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* MOZ_RELEASE_ASSERT, which applies to non-debug builds as well.
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*
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* MOZ_DIAGNOSTIC_ASSERT works like MOZ_RELEASE_ASSERT in Nightly/Aurora and
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* MOZ_ASSERT in Beta/Release - use this when a condition is potentially rare
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* enough to require real user testing to hit, but is not security-sensitive.
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* This can cause user pain, so use it sparingly. If a MOZ_DIAGNOSTIC_ASSERT
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* is firing, it should promptly be converted to a MOZ_ASSERT while the failure
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* is being investigated, rather than letting users suffer.
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*/
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/*
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* Implement MOZ_VALIDATE_ASSERT_CONDITION_TYPE, which is used to guard against
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* accidentally passing something unintended in lieu of an assertion condition.
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*/
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#ifdef __cplusplus
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# include "mozilla/TypeTraits.h"
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namespace mozilla {
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namespace detail {
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template<typename T>
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struct AssertionConditionType
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{
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typedef typename RemoveReference<T>::Type ValueT;
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static_assert(!IsArray<ValueT>::value,
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"Expected boolean assertion condition, got an array or a "
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"string!");
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static_assert(!IsFunction<ValueT>::value,
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"Expected boolean assertion condition, got a function! Did "
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"you intend to call that function?");
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static_assert(!IsFloatingPoint<ValueT>::value,
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"It's often a bad idea to assert that a floating-point number "
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"is nonzero, because such assertions tend to intermittently "
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"fail. Shouldn't your code gracefully handle this case instead "
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"of asserting? Anyway, if you really want to do that, write an "
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"explicit boolean condition, like !!x or x!=0.");
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static const bool isValid = true;
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};
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} // namespace detail
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} // namespace mozilla
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# define MOZ_VALIDATE_ASSERT_CONDITION_TYPE(x) \
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static_assert(mozilla::detail::AssertionConditionType<decltype(x)>::isValid, \
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"invalid assertion condition")
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#else
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# define MOZ_VALIDATE_ASSERT_CONDITION_TYPE(x)
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#endif
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/* First the single-argument form. */
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#define MOZ_ASSERT_HELPER1(expr) \
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do { \
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MOZ_VALIDATE_ASSERT_CONDITION_TYPE(expr); \
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if (MOZ_UNLIKELY(!(expr))) { \
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MOZ_ReportAssertionFailure(#expr, __FILE__, __LINE__); \
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MOZ_CRASH_ANNOTATE("MOZ_RELEASE_ASSERT(" #expr ")"); \
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MOZ_REALLY_CRASH(); \
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} \
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} while (0)
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/* Now the two-argument form. */
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#define MOZ_ASSERT_HELPER2(expr, explain) \
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do { \
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MOZ_VALIDATE_ASSERT_CONDITION_TYPE(expr); \
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if (MOZ_UNLIKELY(!(expr))) { \
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MOZ_ReportAssertionFailure(#expr " (" explain ")", __FILE__, __LINE__); \
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MOZ_CRASH_ANNOTATE("MOZ_RELEASE_ASSERT(" #expr ") (" explain ")"); \
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MOZ_REALLY_CRASH(); \
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} \
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} while (0)
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#define MOZ_RELEASE_ASSERT_GLUE(a, b) a b
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#define MOZ_RELEASE_ASSERT(...) \
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MOZ_RELEASE_ASSERT_GLUE( \
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MOZ_PASTE_PREFIX_AND_ARG_COUNT(MOZ_ASSERT_HELPER, __VA_ARGS__), \
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(__VA_ARGS__))
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#ifdef DEBUG
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|
# define MOZ_ASSERT(...) MOZ_RELEASE_ASSERT(__VA_ARGS__)
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#else
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# define MOZ_ASSERT(...) do { } while (0)
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#endif /* DEBUG */
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#ifdef RELEASE_BUILD
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|
# define MOZ_DIAGNOSTIC_ASSERT MOZ_ASSERT
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#else
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# define MOZ_DIAGNOSTIC_ASSERT MOZ_RELEASE_ASSERT
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#endif
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/*
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|
* MOZ_ASSERT_IF(cond1, cond2) is equivalent to MOZ_ASSERT(cond2) if cond1 is
|
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* true.
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|
*
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* MOZ_ASSERT_IF(isPrime(num), num == 2 || isOdd(num));
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|
*
|
|
* 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".
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|
*/
|
|
#ifdef DEBUG
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|
# define MOZ_ASSERT_IF(cond, expr) \
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do { \
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|
if (cond) { \
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MOZ_ASSERT(expr); \
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|
} \
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} while (0)
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#else
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# define MOZ_ASSERT_IF(cond, expr) do { } while (0)
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#endif
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/*
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|
* MOZ_ASSUME_UNREACHABLE_MARKER() expands to an expression which states that
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* it is undefined behavior for execution to reach this point. No guarantees
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* are made about what will happen if this is reached at runtime. Most code
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|
* should use MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE because it has extra
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* asserts.
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*/
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|
#if defined(__clang__) || defined(__GNUC__)
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# define MOZ_ASSUME_UNREACHABLE_MARKER() __builtin_unreachable()
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|
#elif defined(_MSC_VER)
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|
# define MOZ_ASSUME_UNREACHABLE_MARKER() __assume(0)
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|
#else
|
|
# ifdef __cplusplus
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|
# define MOZ_ASSUME_UNREACHABLE_MARKER() ::abort()
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|
# else
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|
# define MOZ_ASSUME_UNREACHABLE_MARKER() abort()
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|
# endif
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|
#endif
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/*
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|
* MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE([reason]) tells the compiler that it
|
|
* can assume that the macro call cannot be reached during execution. This lets
|
|
* the compiler generate better-optimized code under some circumstances, at the
|
|
* expense of the program's behavior being undefined if control reaches the
|
|
* MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE.
|
|
*
|
|
* In Gecko, you probably should not use this macro outside of performance- or
|
|
* size-critical code, because it's unsafe. If you don't care about code size
|
|
* or performance, you should probably use MOZ_ASSERT or MOZ_CRASH.
|
|
*
|
|
* SpiderMonkey is a different beast, and there it's acceptable to use
|
|
* MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE more widely.
|
|
*
|
|
* Note that MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE is noreturn, so it's valid
|
|
* not to return a value following a MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE
|
|
* call.
|
|
*
|
|
* Example usage:
|
|
*
|
|
* enum ValueType {
|
|
* VALUE_STRING,
|
|
* VALUE_INT,
|
|
* VALUE_FLOAT
|
|
* };
|
|
*
|
|
* int ptrToInt(ValueType type, void* value) {
|
|
* {
|
|
* // We know for sure that type is either INT or FLOAT, and we want this
|
|
* // code to run as quickly as possible.
|
|
* switch (type) {
|
|
* case VALUE_INT:
|
|
* return *(int*) value;
|
|
* case VALUE_FLOAT:
|
|
* return (int) *(float*) value;
|
|
* default:
|
|
* MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("Unexpected ValueType");
|
|
* }
|
|
* }
|
|
*/
|
|
|
|
/*
|
|
* Unconditional assert in debug builds for (assumed) unreachable code paths
|
|
* that have a safe return without crashing in release builds.
|
|
*/
|
|
#define MOZ_ASSERT_UNREACHABLE(reason) \
|
|
MOZ_ASSERT(false, "MOZ_ASSERT_UNREACHABLE: " reason)
|
|
|
|
#define MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE(reason) \
|
|
do { \
|
|
MOZ_ASSERT_UNREACHABLE(reason); \
|
|
MOZ_ASSUME_UNREACHABLE_MARKER(); \
|
|
} while (0)
|
|
|
|
/**
|
|
* MOZ_FALLTHROUGH_ASSERT is an annotation to suppress compiler warnings about
|
|
* switch cases that MOZ_ASSERT(false) (or its alias MOZ_ASSERT_UNREACHABLE) in
|
|
* debug builds, but intentionally fall through in release builds to handle
|
|
* unexpected values.
|
|
*
|
|
* Why do we need MOZ_FALLTHROUGH_ASSERT in addition to MOZ_FALLTHROUGH? In
|
|
* release builds, the MOZ_ASSERT(false) will expand to `do { } while (0)`,
|
|
* requiring a MOZ_FALLTHROUGH annotation to suppress a -Wimplicit-fallthrough
|
|
* warning. In debug builds, the MOZ_ASSERT(false) will expand to something like
|
|
* `if (true) { MOZ_CRASH(); }` and the MOZ_FALLTHROUGH annotation will cause
|
|
* a -Wunreachable-code warning. The MOZ_FALLTHROUGH_ASSERT macro breaks this
|
|
* warning stalemate.
|
|
*
|
|
* // Example before MOZ_FALLTHROUGH_ASSERT:
|
|
* switch (foo) {
|
|
* default:
|
|
* // This case wants to assert in debug builds, fall through in release.
|
|
* MOZ_ASSERT(false); // -Wimplicit-fallthrough warning in release builds!
|
|
* MOZ_FALLTHROUGH; // but -Wunreachable-code warning in debug builds!
|
|
* case 5:
|
|
* return 5;
|
|
* }
|
|
*
|
|
* // Example with MOZ_FALLTHROUGH_ASSERT:
|
|
* switch (foo) {
|
|
* default:
|
|
* // This case asserts in debug builds, falls through in release.
|
|
* MOZ_FALLTHROUGH_ASSERT("Unexpected foo value?!");
|
|
* case 5:
|
|
* return 5;
|
|
* }
|
|
*/
|
|
#ifdef DEBUG
|
|
# define MOZ_FALLTHROUGH_ASSERT(reason) MOZ_CRASH("MOZ_FALLTHROUGH_ASSERT: " reason)
|
|
#else
|
|
# define MOZ_FALLTHROUGH_ASSERT(...) MOZ_FALLTHROUGH
|
|
#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) \
|
|
do { \
|
|
if ( ( expr ) ) { \
|
|
/* Silence MOZ_MUST_USE. */ \
|
|
} \
|
|
} while (0)
|
|
# define MOZ_ALWAYS_FALSE(expr) \
|
|
do { \
|
|
if ( ( expr ) ) { \
|
|
/* Silence MOZ_MUST_USE. */ \
|
|
} \
|
|
} while (0)
|
|
#endif
|
|
|
|
#undef MOZ_DUMP_ASSERTION_STACK
|
|
#undef MOZ_CRASH_CRASHREPORT
|
|
|
|
#endif /* mozilla_Assertions_h */
|