[Bug c++/58678] [4.9 Regression] pykde4-4.11.2 link error (devirtualization too trigger happy)

["nheghathivhistha at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58678

--- Comment #39 from David Kredba <nheghathivhistha at gmail dot com> ---
Hello Markus, Thank you.

Without LTO the reference is different, maybe qHash would be the next one
error.

MakeFiles/kritametadataeditor.dir/kis_meta_data_editor.cc.o: In function
`KisMetaDataEditor::KisMetaDataEditor(QWidget*, KisMetaData::Store*)':
/var/tmp/portage/app-office/calligra-2.8.0/work/calligra-2.8.0/krita/plugins/extensions/metadataeditor/kis_meta_data_editor.cc:79:
undefined reference to `QUiLoader::QUiLoader(QObject*)'
/var/tmp/portage/app-office/calligra-2.8.0/work/calligra-2.8.0/krita/plugins/extensions/metadataeditor/kis_meta_data_editor.cc:82:
undefined reference to `QUiLoader::load(QIODevice*, QWidget*)'
/var/tmp/portage/app-office/calligra-2.8.0/work/calligra-2.8.0/krita/plugins/extensions/metadataeditor/kis_meta_data_editor.cc:85:
undefined reference to `QUiLoader::~QUiLoader()'
/var/tmp/portage/app-office/calligra-2.8.0/work/calligra-2.8.0/krita/plugins/extensions/metadataeditor/kis_meta_data_editor.cc:79:
undefined reference to `QUiLoader::~QUiLoader()'
collect2: error: ld returned 1 exit status
krita/plugins/extensions/metadataeditor/CMakeFiles/kritametadataeditor.dir/build.make:229:
recipe for target 'lib/kritametadataeditor.so' failed


It wanted to link this way:

/usr/bin/x86_64-pc-linux-gnu-g++  -fPIC -flto=4 -fuse-linker-plugin -O2 -ggdb
-pipe -march=native -mtune=native -mno-3dnow -mno-sse4.2 -mno-avx -fno-lto
-fno-use-linker-plugin  -Wnon-virtual-dtor -Wno-long-long -Wundef -Wcast-align
-Wchar-subscripts -Wall -W -Wpointer-arith -Wformat-security -fno-exceptions
-DQT_NO_EXCEPTIONS -fno-check-new -fno-common -Woverloaded-virtual
-fno-threadsafe-statics -fvisibility=hidden -fvisibility-inlines-hidden 
-march=core2 -msse2 -msse3 -mssse3 -msse4.1 -mno-sse4.2 -mno-sse4a -mno-avx
-mno-xop -mno-fma4  -Wabi -fabi-version=0 -ffp-contract=fast -fexceptions
-UQT_NO_EXCEPTIONS -Wl,--enable-new-dtags -Wl,--no-undefined -lc  -flto=4
-fuse-linker-plugin -Wl,--as-needed -Wl,-O2 -Wl,-flto -O2 -ggdb -pipe
-march=native -mtune=native -mno-3dnow -mno-sse4.2 -mno-avx -fno-lto
-fno-use-linker-plugin -shared -Wl,-soname,kritametadataeditor.so -o
../../../../lib/kritametadataeditor.so
CMakeFiles/kritametadataeditor.dir/kritametadataeditor_automoc.cpp.o
CMakeFiles/kritametadataeditor.dir/metadataeditor.cc.o
CMakeFiles/kritametadataeditor.dir/kis_entry_editor.cc.o
CMakeFiles/kritametadataeditor.dir/kis_meta_data_editor.cc.o
CMakeFiles/kritametadataeditor.dir/kis_meta_data_model.cpp.o 
-L/var/tmp/portage/app-office/calligra-2.8.0/work/calligra-2.8.0_build/lib 
-L/usr/lib64/qt4 ../../../../lib/libkritaui.so.13.0.0
/usr/lib64/qt4/libQtUiTools.a ../../../../lib/libkritaimage.so.13.0.0
../../../../lib/libkomain.so.13.0.0 /usr/lib64/libkactivities.so.6.2.0 -lGLU
-lGL -lSM -lICE -lSM -lICE -lX11 -lXext -lXft -lXau -lXdmcp -lXpm
/usr/lib64/qt4/libQtOpenGL.so ../../../../lib/libkowidgets.so.13.0.0
../../../../lib/libkotext.so.13.0.0 ../../../../lib/libflake.so.13.0.0
../../../../lib/libpigmentcms.so.13.0.0 ../../../../lib/libkoplugin.so.13.0.0
-lImath -lIlmImf -lIex -lHalf -lIlmThread -Wl,-Bstatic -lVc -Wl,-Bdynamic
../../../../lib/libkundo2.so.13.0.0 ../../../../lib/libkowidgetutils.so.13.0.0
../../../../lib/libkoodf.so.13.0.0 /usr/lib64/libkio.so.5.12.3
/usr/lib64/qt4/libQtXml.so /usr/lib64/qt4/libQtNetwork.so
/usr/lib64/libkdeui.so.5.12.3 /usr/lib64/qt4/libQtGui.so
/usr/lib64/qt4/libQtSvg.so /usr/lib64/libkdecore.so.5.12.3
/usr/lib64/qt4/libQtDBus.so /usr/lib64/qt4/libQtCore.so -lpthread
-Wl,-rpath,/var/tmp/portage/app-office/calligra-2.8.0/work/calligra-2.8.0_build/lib:/usr/lib64/qt4:
-Wl,-rpath-link,/var/tmp/portage/app-office/calligra-2.8.0/work/calligra-2.8.0_build/lib