From f7eff7251786186ca895c8fc537b304bc89977b3 Mon Sep 17 00:00:00 2001 From: Thiago Macieira Date: Fri, 24 Feb 2012 18:44:17 +0100 Subject: Add a new Q_GLOBAL_STATIC implementation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Unlike the previous implementation, this implementation is locked: only one initialisation is ever run at the same time. It is exception-safe, meaning that a throwing constructor will restart the process. Also, start using the thread-safe behaviour that GCC has offered for a long time and C++11 requires. Change-Id: I20db44f57d258923df64c0051358fd0d9a5ccd51 Reviewed-by: Olivier Goffart Reviewed-by: David Faure (KDE) Reviewed-by: Jędrzej Nowacki --- src/corelib/global/global.pri | 1 + src/corelib/global/qglobal.h | 122 +----------- src/corelib/global/qglobalstatic.h | 157 +++++++++++++++ .../corelib/global/qglobalstatic/qglobalstatic.pro | 12 ++ .../global/qglobalstatic/tst_qglobalstatic.cpp | 214 +++++++++++++++++++++ tests/auto/corelib/kernel/qobject/tst_qobject.cpp | 10 + 6 files changed, 397 insertions(+), 119 deletions(-) create mode 100644 src/corelib/global/qglobalstatic.h create mode 100644 tests/auto/corelib/global/qglobalstatic/qglobalstatic.pro create mode 100644 tests/auto/corelib/global/qglobalstatic/tst_qglobalstatic.cpp diff --git a/src/corelib/global/global.pri b/src/corelib/global/global.pri index 01756c8419..491464621c 100644 --- a/src/corelib/global/global.pri +++ b/src/corelib/global/global.pri @@ -9,6 +9,7 @@ HEADERS += \ global/qendian.h \ global/qnumeric_p.h \ global/qnumeric.h \ + global/qglobalstatic.h \ global/qlibraryinfo.h \ global/qlogging.h \ global/qtypeinfo.h \ diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h index 03cd3dc591..60b6e32522 100644 --- a/src/corelib/global/qglobal.h +++ b/src/corelib/global/qglobal.h @@ -664,125 +664,6 @@ typedef void (*QFunctionPointer)(); # define Q_UNIMPLEMENTED() qWarning("%s:%d: %s: Unimplemented code.", __FILE__, __LINE__, Q_FUNC_INFO) #endif -#if defined(QT_NO_THREAD) - -template -class QGlobalStatic -{ -public: - T *pointer; - inline QGlobalStatic(T *p) : pointer(p) { } - inline ~QGlobalStatic() { pointer = 0; } -}; - -#define Q_GLOBAL_STATIC(TYPE, NAME) \ - static TYPE *NAME() \ - { \ - static TYPE thisVariable; \ - static QGlobalStatic thisGlobalStatic(&thisVariable); \ - return thisGlobalStatic.pointer; \ - } - -#define Q_GLOBAL_STATIC_WITH_ARGS(TYPE, NAME, ARGS) \ - static TYPE *NAME() \ - { \ - static TYPE thisVariable ARGS; \ - static QGlobalStatic thisGlobalStatic(&thisVariable); \ - return thisGlobalStatic.pointer; \ - } - -#define Q_GLOBAL_STATIC_WITH_INITIALIZER(TYPE, NAME, INITIALIZER) \ - static TYPE *NAME() \ - { \ - static TYPE thisVariable; \ - static QGlobalStatic thisGlobalStatic(0); \ - if (!thisGlobalStatic.pointer) { \ - TYPE *x = thisGlobalStatic.pointer = &thisVariable; \ - INITIALIZER; \ - } \ - return thisGlobalStatic.pointer; \ - } - -#else - -// forward declaration, since qatomic.h needs qglobal.h -template class QBasicAtomicPointer; - -// POD for Q_GLOBAL_STATIC -template -class QGlobalStatic -{ -public: - QBasicAtomicPointer pointer; - bool destroyed; -}; - -// Created as a function-local static to delete a QGlobalStatic -template -class QGlobalStaticDeleter -{ -public: - QGlobalStatic &globalStatic; - QGlobalStaticDeleter(QGlobalStatic &_globalStatic) - : globalStatic(_globalStatic) - { } - - inline ~QGlobalStaticDeleter() - { - delete globalStatic.pointer.load(); - globalStatic.pointer.store(0); - globalStatic.destroyed = true; - } -}; - -#define Q_GLOBAL_STATIC(TYPE, NAME) \ - static TYPE *NAME() \ - { \ - static QGlobalStatic thisGlobalStatic \ - = { Q_BASIC_ATOMIC_INITIALIZER(0), false }; \ - if (!thisGlobalStatic.pointer.load() && !thisGlobalStatic.destroyed) { \ - TYPE *x = new TYPE; \ - if (!thisGlobalStatic.pointer.testAndSetOrdered(0, x)) \ - delete x; \ - else \ - static QGlobalStaticDeleter cleanup(thisGlobalStatic); \ - } \ - return thisGlobalStatic.pointer.load(); \ - } - -#define Q_GLOBAL_STATIC_WITH_ARGS(TYPE, NAME, ARGS) \ - static TYPE *NAME() \ - { \ - static QGlobalStatic thisGlobalStatic \ - = { Q_BASIC_ATOMIC_INITIALIZER(0), false }; \ - if (!thisGlobalStatic.pointer.load() && !thisGlobalStatic.destroyed) { \ - TYPE *x = new TYPE ARGS; \ - if (!thisGlobalStatic.pointer.testAndSetOrdered(0, x)) \ - delete x; \ - else \ - static QGlobalStaticDeleter cleanup(thisGlobalStatic); \ - } \ - return thisGlobalStatic.pointer.load(); \ - } - -#define Q_GLOBAL_STATIC_WITH_INITIALIZER(TYPE, NAME, INITIALIZER) \ - static TYPE *NAME() \ - { \ - static QGlobalStatic thisGlobalStatic \ - = { Q_BASIC_ATOMIC_INITIALIZER(0), false }; \ - if (!thisGlobalStatic.pointer.load() && !thisGlobalStatic.destroyed) { \ - QScopedPointer x(new TYPE); \ - INITIALIZER; \ - if (thisGlobalStatic.pointer.testAndSetOrdered(0, x.data())) { \ - static QGlobalStaticDeleter cleanup(thisGlobalStatic); \ - x.take(); \ - } \ - } \ - return thisGlobalStatic.pointer.load(); \ - } - -#endif - Q_DECL_CONSTEXPR static inline bool qFuzzyCompare(double p1, double p2) { return (qAbs(p1 - p2) <= 0.000000000001 * qMin(qAbs(p1), qAbs(p2))); @@ -1089,6 +970,9 @@ template struct QEnableIf { typedef T Type; }; QT_END_NAMESPACE QT_END_HEADER +// Q_GLOBAL_STATIC +#include + // qDebug and friends #include #include diff --git a/src/corelib/global/qglobalstatic.h b/src/corelib/global/qglobalstatic.h new file mode 100644 index 0000000000..78a4acff12 --- /dev/null +++ b/src/corelib/global/qglobalstatic.h @@ -0,0 +1,157 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Intel Corporation +** Contact: http://www.qt-project.org/legal +** +** This file is part of the QtCore module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and Digia. For licensing terms and +** conditions see http://qt.digia.com/licensing. For further information +** use the contact form at http://qt.digia.com/contact-us. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Digia gives you certain additional +** rights. These rights are described in the Digia Qt LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include + +#ifndef QGLOBALSTATIC_H +#define QGLOBALSTATIC_H + +#include + +QT_BEGIN_HEADER +QT_BEGIN_NAMESPACE + +/* + * QGlobalStatic internals: + * + * The pointer is initialized to 0. + * The guard is initialized to 0. + * The guard can assume the following values: + * -2: object initialized and already destroyed + * -1: object initialized and is still valid + * 0: not initialized, the value of the pointer should be null + * +1: initializing, must wait until a state change happens + * (not used in the current implementation) + */ + +namespace QtGlobalStatic { +enum GuardValues { + Destroyed = -2, + Initialized = -1, + Uninitialized = 0, + Initializing = 1 +}; +} + +#if defined(QT_NO_THREAD) || defined(Q_CC_GNU) +// 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 and Mac OS X. + +#define Q_GLOBAL_STATIC_INTERNAL(ARGS) \ + Q_DECL_HIDDEN inline Type *innerFunction() \ + { \ + struct HolderBase { \ + ~HolderBase() Q_DECL_NOTHROW \ + { guard.store(QtGlobalStatic::Destroyed); } \ + }; \ + static struct Holder : public HolderBase { \ + Type value; \ + Holder() \ + Q_DECL_NOEXCEPT_EXPR(noexcept(Type ARGS)) \ + : value ARGS \ + { guard.store(QtGlobalStatic::Initialized); } \ + } 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 +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)) { \ + QMutexLocker locker(&mutex); \ + if (guard.load() == QtGlobalStatic::Uninitialized) { \ + d = new Type ARGS; \ + static struct Cleanup { \ + ~Cleanup() { \ + delete d; \ + guard.store(QtGlobalStatic::Destroyed); \ + } \ + } cleanup; \ + guard.store(QtGlobalStatic::Initialized); \ + } \ + } \ + return d; \ + } +#endif + +// this class must be POD, unless the compiler supports thread-safe statics +template +struct QGlobalStatic +{ + typedef T Type; + + bool isDestroyed() const { return guard.load() <= QtGlobalStatic::Destroyed; } + bool exists() const { return guard.load() == QtGlobalStatic::Initialized; } + operator Type *() { if (isDestroyed()) return 0; return innerFunction(); } + Type *operator()() { if (isDestroyed()) return 0; return innerFunction(); } + Type *operator->() { return innerFunction(); } + Type &operator*() { return *innerFunction(); } +}; + +#define Q_GLOBAL_STATIC_WITH_ARGS(TYPE, NAME, ARGS) \ + namespace { namespace Q_QGS_ ## NAME { \ + typedef TYPE Type; \ + QBasicAtomicInt guard = Q_BASIC_ATOMIC_INITIALIZER(QtGlobalStatic::Uninitialized); \ + Q_GLOBAL_STATIC_INTERNAL(ARGS) \ + } } \ + static QGlobalStatic NAME; + +#define Q_GLOBAL_STATIC(TYPE, NAME) \ + Q_GLOBAL_STATIC_WITH_ARGS(TYPE, NAME, ()) + +QT_END_NAMESPACE +QT_END_HEADER + +#endif // QGLOBALSTATIC_H diff --git a/tests/auto/corelib/global/qglobalstatic/qglobalstatic.pro b/tests/auto/corelib/global/qglobalstatic/qglobalstatic.pro new file mode 100644 index 0000000000..21cab8f67d --- /dev/null +++ b/tests/auto/corelib/global/qglobalstatic/qglobalstatic.pro @@ -0,0 +1,12 @@ +QT += testlib core-private + +QT -= gui + +TARGET = tst_qglobalstatic +CONFIG += console +CONFIG -= app_bundle +CONFIG += exceptions + +SOURCES += tst_qglobalstatic.cpp +DEFINES += SRCDIR=\\\"$$PWD/\\\" +DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0 diff --git a/tests/auto/corelib/global/qglobalstatic/tst_qglobalstatic.cpp b/tests/auto/corelib/global/qglobalstatic/tst_qglobalstatic.cpp new file mode 100644 index 0000000000..b9aa70fe80 --- /dev/null +++ b/tests/auto/corelib/global/qglobalstatic/tst_qglobalstatic.cpp @@ -0,0 +1,214 @@ +/**************************************************************************** +** +** Copyright (C) 2011 Thiago Macieira +** Contact: http://www.qt-project.org/legal +** +** This file is part of the QtCore module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names +** of its contributors may be used to endorse or promote products derived +** from this software without specific prior written permission. +** +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include +#include + +class tst_QGlobalStatic : public QObject +{ + Q_OBJECT + +private Q_SLOTS: + void beforeInitialization(); + void api(); + void constVolatile(); + void exception(); + void threadStressTest(); + void afterDestruction(); +}; + +Q_GLOBAL_STATIC_WITH_ARGS(const int, constInt, (42)) +Q_GLOBAL_STATIC_WITH_ARGS(volatile int, volatileInt, (-47)) + +void otherFunction() +{ + // never called + constInt(); + volatileInt(); +} + +// do not initialize the following Q_GLOBAL_STATIC +Q_GLOBAL_STATIC(int, checkedBeforeInitialization) +void tst_QGlobalStatic::beforeInitialization() +{ + QVERIFY(!checkedBeforeInitialization.exists()); + QVERIFY(!checkedBeforeInitialization.isDestroyed()); +} + +struct Type { + int i; +}; + +Q_GLOBAL_STATIC(Type, checkedAfterInitialization) +void tst_QGlobalStatic::api() +{ + // check the API + QVERIFY((Type *)checkedAfterInitialization); + QVERIFY(checkedAfterInitialization()); + *checkedAfterInitialization = Type(); + *checkedAfterInitialization() = Type(); + + checkedAfterInitialization()->i = 47; + checkedAfterInitialization->i = 42; + QCOMPARE(checkedAfterInitialization()->i, 42); + checkedAfterInitialization()->i = 47; + QCOMPARE(checkedAfterInitialization->i, 47); + + QVERIFY(checkedAfterInitialization.exists()); + QVERIFY(!checkedAfterInitialization.isDestroyed()); +} + +void tst_QGlobalStatic::constVolatile() +{ + QCOMPARE(*constInt(), 42); + QCOMPARE((int)*volatileInt(), -47); + QCOMPARE(*constInt(), 42); + QCOMPARE((int)*volatileInt(), -47); +} + +struct ThrowingType +{ + static QBasicAtomicInt constructedCount; + static QBasicAtomicInt destructedCount; + ThrowingType(QBasicAtomicInt &throwControl) + { + constructedCount.ref(); + if (throwControl.fetchAndAddRelaxed(-1) != 0) + throw 0; + } + ~ThrowingType() { destructedCount.ref(); } +}; +QBasicAtomicInt ThrowingType::constructedCount = Q_BASIC_ATOMIC_INITIALIZER(0); +QBasicAtomicInt ThrowingType::destructedCount = Q_BASIC_ATOMIC_INITIALIZER(0); + +QBasicAtomicInt exceptionControlVar = Q_BASIC_ATOMIC_INITIALIZER(1); +Q_GLOBAL_STATIC_WITH_ARGS(ThrowingType, exceptionGS, (exceptionControlVar)) +void tst_QGlobalStatic::exception() +{ + if (exceptionControlVar.load() != 1) + QSKIP("This test cannot be run more than once"); + ThrowingType::constructedCount.store(0); + ThrowingType::destructedCount.store(0); + + bool exceptionCaught = false; + try { + exceptionGS(); + } catch (int) { + exceptionCaught = true; + } + QCOMPARE(ThrowingType::constructedCount.load(), 1); + QVERIFY(exceptionCaught); + + exceptionGS(); + QCOMPARE(ThrowingType::constructedCount.load(), 2); +} + +QBasicAtomicInt threadStressTestControlVar = Q_BASIC_ATOMIC_INITIALIZER(5); +Q_GLOBAL_STATIC_WITH_ARGS(ThrowingType, threadStressTestGS, (threadStressTestControlVar)) + + +void tst_QGlobalStatic::threadStressTest() +{ + class ThreadStressTestThread: public QThread + { + public: + QReadWriteLock *lock; + void run() + { + QReadLocker l(lock); + //usleep(qrand() * 200 / RAND_MAX); + // thundering herd + try { + threadStressTestGS(); + } catch (int) { + } + } + }; + + ThrowingType::constructedCount.store(0); + ThrowingType::destructedCount.store(0); + int expectedConstructionCount = threadStressTestControlVar.load() + 1; + if (expectedConstructionCount <= 0) + QSKIP("This test cannot be run more than once"); + + const int numThreads = 200; + ThreadStressTestThread threads[numThreads]; + QReadWriteLock lock; + lock.lockForWrite(); + for (int i = 0; i < numThreads; ++i) { + threads[i].lock = &lock; + threads[i].start(); + } + + // wait for all threads + // release the herd + lock.unlock(); + + for (int i = 0; i < numThreads; ++i) + threads[i].wait(); + + QCOMPARE(ThrowingType::constructedCount.loadAcquire(), expectedConstructionCount); + QCOMPARE(ThrowingType::destructedCount.loadAcquire(), 0); +} + +Q_GLOBAL_STATIC(int, checkedAfterDestruction) +void tst_QGlobalStatic::afterDestruction() +{ + // this test will not produce results now + // it will simply run some code on destruction (after the global statics have been deleted) + // if that fails, this will cause a crash + + // static destruction is LIFO: so we must add our exit-time code before the + // global static is used for the first time + static struct RunAtExit { + ~RunAtExit() { + int *ptr = checkedAfterDestruction(); + if (ptr) + qFatal("Global static is not null as was expected"); + } + } runAtExit; + (void) runAtExit; + + *checkedAfterDestruction = 42; +} + +QTEST_APPLESS_MAIN(tst_QGlobalStatic); + +#include "tst_qglobalstatic.moc" diff --git a/tests/auto/corelib/kernel/qobject/tst_qobject.cpp b/tests/auto/corelib/kernel/qobject/tst_qobject.cpp index 581644b19f..d7add383e1 100644 --- a/tests/auto/corelib/kernel/qobject/tst_qobject.cpp +++ b/tests/auto/corelib/kernel/qobject/tst_qobject.cpp @@ -144,6 +144,16 @@ private slots: void disconnectDoesNotLeakFunctor(); }; +struct QObjectCreatedOnShutdown +{ + QObjectCreatedOnShutdown() {} + ~QObjectCreatedOnShutdown() + { + QObject(); + } +}; +static QObjectCreatedOnShutdown s_qobjectCreatedOnShutdown; + class SenderObject : public QObject { Q_OBJECT -- cgit v1.2.3