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Clenaup Q_COMPILER_THREADSAFE_STATICS

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Change-Id: I1cf0646d4e6c9b30a7ef6538d81f92faf2e511e1
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Fabian Kosmale 2021-03-20 18:35:59 +01:00
parent 52e0a91fbc
commit b8b50c6c7a
2 changed files with 5 additions and 55 deletions
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17
src/corelib/global/qcompilerdetection.h
View File

@ -378,7 +378,6 @@
# define Q_COMPILER_STATIC_ASSERT
# define Q_COMPILER_TEMPLATE_ALIAS
# define Q_COMPILER_THREAD_LOCAL
# define Q_COMPILER_THREADSAFE_STATICS
# define Q_COMPILER_UDL
# define Q_COMPILER_UNICODE_STRINGS
# define Q_COMPILER_UNIFORM_INIT
@ -573,6 +572,11 @@
* Q_COMPILER_RESTRICTED_VLA variable-length arrays, prior to __cpp_runtime_arrays
*/
/*
* Now that we require C++17, we unconditionally expect threadsafe statics mandated since C++11
*/
#define Q_COMPILER_THREADSAFE_STATICS
#ifdef __cplusplus
# if __cplusplus < 201103L && !defined(Q_CC_MSVC)
# error Qt requires a C++11 compiler and yours does not seem to be that.
@ -582,7 +586,6 @@
#if defined(Q_CC_INTEL) && !defined(Q_CC_MSVC)
# define Q_COMPILER_RESTRICTED_VLA
# define Q_COMPILER_VARIADIC_MACROS // C++11 feature supported as an extension in other modes, too
# define Q_COMPILER_THREADSAFE_STATICS
# if __INTEL_COMPILER < 1200
# define Q_NO_TEMPLATE_FRIENDS
# endif
@ -658,7 +661,6 @@
#if defined(Q_CC_CLANG) && !defined(Q_CC_INTEL) && !defined(Q_CC_MSVC)
/* General C++ features */
# define Q_COMPILER_RESTRICTED_VLA
# define Q_COMPILER_THREADSAFE_STATICS
# if __has_feature(attribute_deprecated_with_message)
# define Q_DECL_DEPRECATED_X(text) __attribute__ ((__deprecated__(text)))
# endif
@ -826,7 +828,6 @@
#if defined(Q_CC_GNU) && !defined(Q_CC_INTEL) && !defined(Q_CC_CLANG)
# define Q_COMPILER_RESTRICTED_VLA
# define Q_COMPILER_THREADSAFE_STATICS
# if Q_CC_GNU >= 403
// GCC supports binary literals in C, C++98 and C++11 modes
# define Q_COMPILER_BINARY_LITERALS
@ -980,7 +981,6 @@
# define Q_COMPILER_ATTRIBUTES
// Almost working, see https://connect.microsoft.com/VisualStudio/feedback/details/2011648
//# define Q_COMPILER_CONSTEXPR
# define Q_COMPILER_THREADSAFE_STATICS
# define Q_COMPILER_UNIFORM_INIT
# endif
# if _MSC_VER >= 1910
@ -1048,13 +1048,6 @@
# define __USE_CONSTEXPR 1
# define __USE_NOEXCEPT 1
# endif
# if defined(Q_COMPILER_THREADSAFE_STATICS) && defined(Q_OS_MAC)
// Apple's low-level implementation of the C++ support library
// (libc++abi.dylib, shared between libstdc++ and libc++) has deadlocks. The
// C++11 standard requires the deadlocks to be removed, so this will eventually
// be fixed; for now, let's disable this.
# undef Q_COMPILER_THREADSAFE_STATICS
# endif
#endif
/*

43
src/corelib/global/qglobalstatic.h
View File

@ -55,17 +55,6 @@ enum GuardValues {
};
}
#if !QT_CONFIG(thread) || defined(Q_COMPILER_THREADSAFE_STATICS)
// some compilers support thread-safe statics
// The IA-64 C++ ABI requires this, so we know that all GCC versions since 3.4
// support it. C++11 also requires this behavior.
// Clang and Intel CC masquerade as GCC when compiling on Linux.
//
// Apple's libc++abi however uses a global lock for initializing local statics,
// which will block other threads also trying to initialize a local static
// until the constructor returns ...
// We better avoid these kind of problems by using our own locked implementation.
#if defined(Q_OS_UNIX) && defined(Q_CC_INTEL)
// Work around Intel issue ID 6000058488:
// local statics inside an inline function inside an anonymous namespace are global
@ -94,39 +83,7 @@ enum GuardValues {
} holder; \
return &holder.value; \
}
#else
// We don't know if this compiler supports thread-safe global statics
// so use our own locked implementation
QT_END_NAMESPACE
#include <QtCore/qmutex.h>
#include <mutex>
QT_BEGIN_NAMESPACE
#define Q_GLOBAL_STATIC_INTERNAL(ARGS) \
Q_DECL_HIDDEN inline Type *innerFunction() \
{ \
static Type *d; \
static QBasicMutex mutex; \
int x = guard.loadAcquire(); \
if (Q_UNLIKELY(x >= QtGlobalStatic::Uninitialized)) { \
const std::lock_guard<QBasicMutex> locker(mutex); \
if (guard.loadRelaxed() == QtGlobalStatic::Uninitialized) { \
d = new Type ARGS; \
static struct Cleanup { \
Cleanup() = default; \
~Cleanup() { \
delete d; \
guard.storeRelaxed(QtGlobalStatic::Destroyed); \
} \
Q_DISABLE_COPY_MOVE(Cleanup) \
} cleanup; \
guard.storeRelease(QtGlobalStatic::Initialized); \
} \
} \
return d; \
}
#endif
// this class must be POD, unless the compiler supports thread-safe statics
template <typename T, T *(&innerFunction)(), QBasicAtomicInt &guard>