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Plug padding holes in QHostAddressPrivate

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On ABIs where quint64 is aligned on 8-byte boundaries (such 32-bit
Windows and all 64-bit systems), there was a padding hole of 4 bytes
between QHostAddressPrivate::a and the anonymous union. If we move the
member to after the union, there is no hole anymore.

That operation causes the tail padding to grow from 3 to 7 bytes. Since
we also don't need full 32 bits for the protocol, we can shrink the
structure by 8 bytes on those architectures and by 4 bytes on 32-bit
Unix systems.

Change-Id: I461e9fc7199748faa187ffff1415d6601a7bd777
Reviewed-by: hjk <hjk@theqtcompany.com>
This commit is contained in:
Thiago Macieira 2015-11-11 19:22:43 -08:00
parent 7835b260a9
commit b05741937c
2 changed files with 4 additions and 5 deletions
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2
src/corelib/global/qhooks.cpp
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@ -67,7 +67,7 @@ quintptr Q_CORE_EXPORT qtHookData[] = {
// The required sizes and offsets are tested in tests/auto/other/toolsupport. // The required sizes and offsets are tested in tests/auto/other/toolsupport.
// When this fails and the change was intentional, adjust the test and // When this fails and the change was intentional, adjust the test and
// adjust this value here. // adjust this value here.
4 5
}; };
Q_STATIC_ASSERT(QHooks::LastHookIndex == sizeof(qtHookData) / sizeof(qtHookData[0])); Q_STATIC_ASSERT(QHooks::LastHookIndex == sizeof(qtHookData) / sizeof(qtHookData[0]));

7
src/network/kernel/qhostaddress.cpp
View File

@ -115,14 +115,13 @@ public:
QString ipString; QString ipString;
QString scopeId; QString scopeId;
quint32 a; // IPv4 address
union { union {
Q_IPV6ADDR a6; // IPv6 address Q_IPV6ADDR a6; // IPv6 address
struct { quint64 c[2]; } a6_64; struct { quint64 c[2]; } a6_64;
struct { quint32 c[4]; } a6_32; struct { quint32 c[4]; } a6_32;
}; };
QAbstractSocket::NetworkLayerProtocol protocol; quint32 a; // IPv4 address
qint8 protocol;
bool isParsed; bool isParsed;
friend class QHostAddress; friend class QHostAddress;
@ -701,7 +700,7 @@ quint32 QHostAddress::toIPv4Address(bool *ok) const
QAbstractSocket::NetworkLayerProtocol QHostAddress::protocol() const QAbstractSocket::NetworkLayerProtocol QHostAddress::protocol() const
{ {
QT_ENSURE_PARSED(this); QT_ENSURE_PARSED(this);
return d->protocol; return QAbstractSocket::NetworkLayerProtocol(d->protocol);
} }
/*! /*!