diff options
| author | Marc Mutz <marc.mutz@qt.io> | 2022-12-15 17:45:56 +0100 |
|---|---|---|
| committer | Marc Mutz <marc.mutz@qt.io> | 2022-12-16 17:21:56 +0000 |
| commit | 8602a224b6ade5680329270d8d573b786a7a81a1 (patch) | |
| tree | 15ce626bb63d17379115d2b55447cdb04ef5610e /cmake/modulecppexports.h.in | |
| parent | 8e5806b6807df0d39f3bbd2a1c0ed590426e1aa0 (diff) | |
QT_INLINE_SINCE: never inline for static Qt builds
Static Qt builds are not covered by BC guarantees, but since all
'libraries' are linked into a single executable, we face in all users
of the library the same ODR violation that we faced within the
implementation DLL: we can't define the same symbol as inline in some
TUs and out-of-line in others.
In the past, we decided to always inline in static builds, but that
breaks users which, by Hyrum's Law, have come to depend on the
non-existent BC guarantees for static Qt builds.
By switching to never inline¹ in static builds, we restore BC for such
users. The performance issues should be minimal, since LTO will anyway
inline whatever it wants, independent on how it was declared.
¹ except when the deprecation point has passed over the Qt version the
API was inlined (-disable-deprecated-up-to configure switch).
[ChangeLog][QtCore] Restored binary compatibility for static Qt
builds broken by the QT_INLINE_SINCE mechanism. Qt still does not
guarantee BC for static build configurations otherwise.
Fixes: QTBUG-109449
Pick-to: 6.5 6.4
Change-Id: Ie3fa62621b74dc5e9dac301b9882c0e3c3999eaf
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Diffstat (limited to 'cmake/modulecppexports.h.in')
| -rw-r--r-- | cmake/modulecppexports.h.in | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/cmake/modulecppexports.h.in b/cmake/modulecppexports.h.in index 725d9d79f1..a7a349084e 100644 --- a/cmake/modulecppexports.h.in +++ b/cmake/modulecppexports.h.in @@ -16,8 +16,9 @@ # define Q_@module_define_infix@_EXPORT #endif -#if !defined(QT_BUILD_@module_define_infix@_LIB) || defined(QT_STATIC) +#if !defined(QT_BUILD_@module_define_infix@_LIB) && !defined(QT_STATIC) /* outside library → inline decl + defi */ +/* static builds treat everything as part of the library, so they never inline */ # define QT_@module_define_infix@_INLINE_SINCE(major, minor) inline # define QT_@module_define_infix@_INLINE_IMPL_SINCE(major, minor) 1 #elif defined(QT_@module_define_infix@_BUILD_REMOVED_API) |