diff options
| author | Jędrzej Nowacki <jedrzej.nowacki@digia.com> | 2013-01-10 10:05:02 +0100 |
|---|---|---|
| committer | The Qt Project <gerrit-noreply@qt-project.org> | 2013-01-10 17:58:13 +0100 |
| commit | 3b0ed624351441a2d7be45cf9582fd36955ae860 (patch) | |
| tree | 49def7351d86d5824a7b6a44982c09d928544f37 /src/corelib | |
| parent | 7ff47c7bfa5d58a509bb40e1f62777b8d52409ff (diff) | |
Protect Q_UNREACHABLE and Q_ASSUME by Q_ASSERT.
Both Q_UNREACHABLE and Q_ASSUME with an invalid condition can produce
really weird side effects and crashes.
Change-Id: I4d808c705ae98388ef5853e6539b70bd5e5ad34b
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Diffstat (limited to 'src/corelib')
| -rw-r--r-- | src/corelib/global/qcompilerdetection.h | 37 | ||||
| -rw-r--r-- | src/corelib/global/qglobal.cpp | 4 |
2 files changed, 29 insertions, 12 deletions
diff --git a/src/corelib/global/qcompilerdetection.h b/src/corelib/global/qcompilerdetection.h index 2c471bdfc3..b88309d1e7 100644 --- a/src/corelib/global/qcompilerdetection.h +++ b/src/corelib/global/qcompilerdetection.h @@ -94,8 +94,8 @@ # define Q_FUNC_INFO __FUNCSIG__ # define Q_ALIGNOF(type) __alignof(type) # define Q_DECL_ALIGN(n) __declspec(align(n)) -# define Q_ASSUME(expr) __assume(expr) -# define Q_UNREACHABLE() __assume(0) +# define Q_ASSUME_IMPL(expr) __assume(expr) +# define Q_UNREACHABLE_IMPL() __assume(0) # define Q_NORETURN __declspec(noreturn) # define Q_DECL_DEPRECATED __declspec(deprecated) # define Q_DECL_EXPORT __declspec(dllexport) @@ -150,18 +150,18 @@ # if defined(__INTEL_COMPILER) /* Intel C++ also masquerades as GCC */ # define Q_CC_INTEL -# define Q_ASSUME(expr) __assume(expr) -# define Q_UNREACHABLE() __assume(0) +# define Q_ASSUME_IMPL(expr) __assume(expr) +# define Q_UNREACHABLE_IMPL() __assume(0) # elif defined(__clang__) /* Clang also masquerades as GCC */ # define Q_CC_CLANG -# define Q_ASSUME(expr) if (expr){} else __builtin_unreachable() -# define Q_UNREACHABLE() __builtin_unreachable() +# define Q_ASSUME_IMPL(expr) if (expr){} else __builtin_unreachable() +# define Q_UNREACHABLE_IMPL() __builtin_unreachable() # else /* Plain GCC */ # if (__GNUC__ * 100 + __GNUC_MINOR__) >= 405 -# define Q_ASSUME(expr) if (expr){} else __builtin_unreachable() -# define Q_UNREACHABLE() __builtin_unreachable() +# define Q_ASSUME_IMPL(expr) if (expr){} else __builtin_unreachable() +# define Q_UNREACHABLE_IMPL() __builtin_unreachable() # endif # endif @@ -789,11 +789,11 @@ #ifndef Q_UNLIKELY # define Q_UNLIKELY(x) (x) #endif -#ifndef Q_ASSUME -# define Q_ASSUME(expr) qt_noop() +#ifndef Q_ASSUME_IMPL +# define Q_ASSUME_IMPL(expr) qt_noop() #endif -#ifndef Q_UNREACHABLE -# define Q_UNREACHABLE() qt_noop() +#ifndef Q_UNREACHABLE_IMPL +# define Q_UNREACHABLE_IMPL() qt_noop() #endif #ifndef Q_ALLOC_SIZE # define Q_ALLOC_SIZE(x) @@ -851,4 +851,17 @@ #define qMove(x) (x) #endif +#define Q_UNREACHABLE() \ + do {\ + Q_ASSERT_X(false, "Q_UNREACHABLE()", "Q_UNREACHABLE was reached");\ + Q_UNREACHABLE_IMPL();\ + } while (0) + +#define Q_ASSUME(Expr) \ + do {\ + const bool valueOfExpression = Expr;\ + Q_ASSERT_X(valueOfExpression, "Q_ASSUME()", "Assumption in Q_ASSUME(\"" #Expr "\") was not correct");\ + Q_ASSUME_IMPL(valueOfExpression);\ + } while (0) + #endif // QCOMPILERDETECTION_H diff --git a/src/corelib/global/qglobal.cpp b/src/corelib/global/qglobal.cpp index 3881b166b1..6818b1d64d 100644 --- a/src/corelib/global/qglobal.cpp +++ b/src/corelib/global/qglobal.cpp @@ -1829,6 +1829,8 @@ const QSysInfo::WinVersion QSysInfo::WindowsVersion = QSysInfo::windowsVersion() that the current code execution cannot be reached. That is, Q_ASSUME(false) is equivalent to Q_UNREACHABLE(). + In debug builds the condition is enforced by an assert to facilitate debugging. + \note Q_LIKELY() tells the compiler that the expression is likely, but not the only possibility. Q_ASSUME tells the compiler that it is the only possibility. @@ -1863,6 +1865,8 @@ const QSysInfo::WinVersion QSysInfo::WindowsVersion = QSysInfo::windowsVersion() By using this macro in impossible conditions, code coverage may be improved as dead code paths may be eliminated. + In debug builds the condition is enforced by an assert to facilitate debugging. + \sa Q_ASSERT(), Q_ASSUME(), qFatal() */ |