From d2a988512efcad7a72c6624f7015fc08271ae0a6 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Tor=20Arne=20Vestb=C3=B8?= Date: Sat, 22 Jul 2017 16:41:44 +0200 Subject: macOS: Detect use of heap-allocated QMacAutoReleasePool QMacAutoReleasePool is backed by an NSAutoreleasePool, which documents that "you should always drain an autorelease pool in the same context (invocation of a method or function, or body of a loop) that it was created". This means allocating QMacAutoReleasePool on the heap is not a supported use-case, but unfortunately we can't detect it on construction time. Instead we detect whether or not the associated NSAutoreleasePool has been drained, and prevent a double-drain of the pool. Change-Id: Ifd7380a06152e9e742d2e199476ed3adab326d9c Reviewed-by: Simon Hausmann --- src/corelib/kernel/qcore_mac_objc.mm | 66 +++++++++++- src/corelib/kernel/qcore_mac_p.h | 4 + .../qmacautoreleasepool/qmacautoreleasepool.pro | 4 + .../qmacautoreleasepool/tst_qmacautoreleasepool.mm | 111 +++++++++++++++++++++ tests/auto/corelib/tools/tools.pro | 1 + 5 files changed, 185 insertions(+), 1 deletion(-) create mode 100644 tests/auto/corelib/tools/qmacautoreleasepool/qmacautoreleasepool.pro create mode 100644 tests/auto/corelib/tools/qmacautoreleasepool/tst_qmacautoreleasepool.mm diff --git a/src/corelib/kernel/qcore_mac_objc.mm b/src/corelib/kernel/qcore_mac_objc.mm index db7e55f4b1..24d73fa8be 100644 --- a/src/corelib/kernel/qcore_mac_objc.mm +++ b/src/corelib/kernel/qcore_mac_objc.mm @@ -84,18 +84,82 @@ QT_FOR_EACH_MUTABLE_CORE_GRAPHICS_TYPE(QT_DECLARE_WEAK_QDEBUG_OPERATOR_FOR_CF_TY // ------------------------------------------------------------------------- +QT_END_NAMESPACE +QT_USE_NAMESPACE +@interface QT_MANGLE_NAMESPACE(QMacAutoReleasePoolTracker) : NSObject +{ + NSAutoreleasePool **m_pool; +} +-(id)initWithPool:(NSAutoreleasePool**)pool; +@end +@implementation QT_MANGLE_NAMESPACE(QMacAutoReleasePoolTracker) +-(id)initWithPool:(NSAutoreleasePool**)pool +{ + if (self = [super init]) + m_pool = pool; + return self; +} +-(void)dealloc +{ + if (*m_pool) { + // The pool is still valid, which means we're not being drained from + // the corresponding QMacAutoReleasePool (see below). + + // QMacAutoReleasePool has only a single member, the NSAutoreleasePool* + // so the address of that member is also the QMacAutoReleasePool itself. + QMacAutoReleasePool *pool = reinterpret_cast(m_pool); + qWarning() << "Premature drain of" << pool << "This can happen if you've allocated" + << "the pool on the heap, or as a member of a heap-allocated object. This is not a" + << "supported use of QMacAutoReleasePool, and might result in crashes when objects" + << "in the pool are deallocated and then used later on under the assumption they" + << "will be valid until" << pool << "has been drained."; + + // Reset the pool so that it's not drained again later on + *m_pool = nullptr; + } + + [super dealloc]; +} +@end +QT_NAMESPACE_ALIAS_OBJC_CLASS(QMacAutoReleasePoolTracker); +QT_BEGIN_NAMESPACE + QMacAutoReleasePool::QMacAutoReleasePool() : pool([[NSAutoreleasePool alloc] init]) { + [[[QMacAutoReleasePoolTracker alloc] initWithPool: + reinterpret_cast(&pool)] autorelease]; } QMacAutoReleasePool::~QMacAutoReleasePool() { + if (!pool) { + qWarning() << "Prematurely drained pool" << this << "finally drained. Any objects belonging" + << "to this pool have already been released, and have potentially been invalid since the" + << "premature drain earlier on."; + return; + } + + // Save and reset pool before draining, so that the pool tracker can know + // that it's being drained by its owning pool. + NSAutoreleasePool *savedPool = static_cast(pool); + pool = nullptr; + // Drain behaves the same as release, with the advantage that // if we're ever used in a garbage-collected environment, the // drain acts as a hint to the garbage collector to collect. - [static_cast(pool) drain]; + [savedPool drain]; +} + +#ifndef QT_NO_DEBUG_STREAM +QDebug operator<<(QDebug debug, const QMacAutoReleasePool *pool) +{ + QDebugStateSaver saver(debug); + debug.nospace(); + debug << "QMacAutoReleasePool(" << (const void *)pool << ')'; + return debug; } +#endif // !QT_NO_DEBUG_STREAM #ifdef Q_OS_MACOS /* diff --git a/src/corelib/kernel/qcore_mac_p.h b/src/corelib/kernel/qcore_mac_p.h index 5522a617b3..13143a08bb 100644 --- a/src/corelib/kernel/qcore_mac_p.h +++ b/src/corelib/kernel/qcore_mac_p.h @@ -153,6 +153,10 @@ Q_CORE_EXPORT QChar qt_mac_qtKey2CocoaKey(Qt::Key key); Q_CORE_EXPORT Qt::Key qt_mac_cocoaKey2QtKey(QChar keyCode); #endif +#ifndef QT_NO_DEBUG_STREAM +QDebug operator<<(QDebug debug, const QMacAutoReleasePool *pool); +#endif + Q_CORE_EXPORT void qt_apple_check_os_version(); QT_END_NAMESPACE diff --git a/tests/auto/corelib/tools/qmacautoreleasepool/qmacautoreleasepool.pro b/tests/auto/corelib/tools/qmacautoreleasepool/qmacautoreleasepool.pro new file mode 100644 index 0000000000..26b3a47472 --- /dev/null +++ b/tests/auto/corelib/tools/qmacautoreleasepool/qmacautoreleasepool.pro @@ -0,0 +1,4 @@ +CONFIG += testcase +TARGET = tst_qmacautoreleasepool +QT = core testlib +SOURCES = tst_qmacautoreleasepool.mm diff --git a/tests/auto/corelib/tools/qmacautoreleasepool/tst_qmacautoreleasepool.mm b/tests/auto/corelib/tools/qmacautoreleasepool/tst_qmacautoreleasepool.mm new file mode 100644 index 0000000000..8f1069f419 --- /dev/null +++ b/tests/auto/corelib/tools/qmacautoreleasepool/tst_qmacautoreleasepool.mm @@ -0,0 +1,111 @@ +/**************************************************************************** +** +** Copyright (C) 2017 The Qt Company Ltd. +** Contact: https://www.qt.io/licensing/ +** +** This file is part of the test suite of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:GPL-EXCEPT$ +** 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 The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3 as published by the Free Software +** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include + +#include + +class tst_QMacAutoreleasePool : public QObject +{ + Q_OBJECT +private slots: + void noPool(); + void rootLevelPool(); + void stackAllocatedPool(); + void heapAllocatedPool(); +}; + +static id lastDeallocedObject = nil; + +@interface DeallocTracker : NSObject @end +@implementation DeallocTracker +-(void)dealloc +{ + lastDeallocedObject = self; + [super dealloc]; +} +@end + +void tst_QMacAutoreleasePool::noPool() +{ + // No pool, will not be released, but should not crash + + [[[DeallocTracker alloc] init] autorelease]; +} + +void tst_QMacAutoreleasePool::rootLevelPool() +{ + // The root level case, no NSAutoreleasePool since we're not in the main + // runloop, and objects autoreleased as part of main. + + NSObject *allocedObject = nil; + { + QMacAutoReleasePool qtPool; + allocedObject = [[[DeallocTracker alloc] init] autorelease]; + } + QCOMPARE(lastDeallocedObject, allocedObject); +} + +void tst_QMacAutoreleasePool::stackAllocatedPool() +{ + // The normal case, other pools surrounding our pool, draining + // our pool before any other pool. + + NSObject *allocedObject = nil; + NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; + { + QMacAutoReleasePool qtPool; + allocedObject = [[[DeallocTracker alloc] init] autorelease]; + } + QCOMPARE(lastDeallocedObject, allocedObject); + [pool drain]; +} + +void tst_QMacAutoreleasePool::heapAllocatedPool() +{ + // The special case, a pool allocated on the heap, or as a member of a + // heap allocated object. This is not a supported use of QMacAutoReleasePool, + // and will result in warnings if the pool is prematurely drained. + + NSObject *allocedObject = nil; + { + NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; + QMacAutoReleasePool *qtPool = nullptr; + { + qtPool = new QMacAutoReleasePool; + allocedObject = [[[DeallocTracker alloc] init] autorelease]; + } + [pool drain]; + delete qtPool; + } + QCOMPARE(lastDeallocedObject, allocedObject); +} + +QTEST_APPLESS_MAIN(tst_QMacAutoreleasePool) + +#include "tst_qmacautoreleasepool.moc" diff --git a/tests/auto/corelib/tools/tools.pro b/tests/auto/corelib/tools/tools.pro index 6720307d59..f35ed026ac 100644 --- a/tests/auto/corelib/tools/tools.pro +++ b/tests/auto/corelib/tools/tools.pro @@ -67,3 +67,4 @@ SUBDIRS=\ qvector_strictiterators \ qversionnumber +darwin: SUBDIRS += qmacautoreleasepool -- cgit v1.2.3