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Use load() instead of implicit cast when using QueuedConnection

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queued_activate() sets the argumentTypes atomic pointer on first use, which
mixes a load, memory initialization, test-and-set-ordered, and
another load. The explicit memory ordering is necessary to ensure
that the memory stores happen in program order.

Change-Id: Id1f8641f9cd081ce81aa8e830692f7af8261e84b
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Bradley T. Hughes 2011-09-28 12:03:17 +02:00 committed by Qt by Nokia
parent ba90d5cc8b
commit d2aaa13820
1 changed files with 15 additions and 12 deletions
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27
src/corelib/kernel/qobject.cpp
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@ -922,8 +922,9 @@ QObject::~QObject()
QObjectPrivate::Connection::~Connection() QObjectPrivate::Connection::~Connection()
{ {
if (argumentTypes != &DIRECT_CONNECTION_ONLY) int *v = argumentTypes.load();
delete [] static_cast<int *>(argumentTypes); if (v != &DIRECT_CONNECTION_ONLY)
delete [] v;
} }
@ -3220,20 +3221,22 @@ void QMetaObject::connectSlotsByName(QObject *o)
static void queued_activate(QObject *sender, int signal, QObjectPrivate::Connection *c, void **argv) static void queued_activate(QObject *sender, int signal, QObjectPrivate::Connection *c, void **argv)
{ {
if (!c->argumentTypes && c->argumentTypes != &DIRECT_CONNECTION_ONLY) { int *argumentTypes = c->argumentTypes.load();
if (!argumentTypes && argumentTypes != &DIRECT_CONNECTION_ONLY) {
QMetaMethod m = sender->metaObject()->method(signal); QMetaMethod m = sender->metaObject()->method(signal);
int *tmp = queuedConnectionTypes(m.parameterTypes()); argumentTypes = queuedConnectionTypes(m.parameterTypes());
if (!tmp) // cannot queue arguments if (!argumentTypes) // cannot queue arguments
tmp = &DIRECT_CONNECTION_ONLY; argumentTypes = &DIRECT_CONNECTION_ONLY;
if (!c->argumentTypes.testAndSetOrdered(0, tmp)) { if (!c->argumentTypes.testAndSetOrdered(0, argumentTypes)) {
if (tmp != &DIRECT_CONNECTION_ONLY) if (argumentTypes != &DIRECT_CONNECTION_ONLY)
delete [] tmp; delete [] argumentTypes;
argumentTypes = c->argumentTypes.load();
} }
} }
if (c->argumentTypes == &DIRECT_CONNECTION_ONLY) // cannot activate if (argumentTypes == &DIRECT_CONNECTION_ONLY) // cannot activate
return; return;
int nargs = 1; // include return type int nargs = 1; // include return type
while (c->argumentTypes[nargs-1]) while (argumentTypes[nargs-1])
++nargs; ++nargs;
int *types = (int *) qMalloc(nargs*sizeof(int)); int *types = (int *) qMalloc(nargs*sizeof(int));
Q_CHECK_PTR(types); Q_CHECK_PTR(types);
@ -3242,7 +3245,7 @@ static void queued_activate(QObject *sender, int signal, QObjectPrivate::Connect
types[0] = 0; // return type types[0] = 0; // return type
args[0] = 0; // return value args[0] = 0; // return value
for (int n = 1; n < nargs; ++n) for (int n = 1; n < nargs; ++n)
args[n] = QMetaType::create((types[n] = c->argumentTypes[n-1]), argv[n]); args[n] = QMetaType::create((types[n] = argumentTypes[n-1]), argv[n]);
QCoreApplication::postEvent(c->receiver, new QMetaCallEvent(c->method_offset, QCoreApplication::postEvent(c->receiver, new QMetaCallEvent(c->method_offset,
c->method_relative, c->method_relative,
c->callFunction, c->callFunction,