Hi,all:
Now,I cross-compile QT 4.6.0 for arm(LPC3250),and now I meet a strange segment fault when I try to run a GUI program (even "hello world").
Here is my hello.cpp:
Qt Code: 
  1. #include<QtGui>
  2. int main(int argc,char * argv[])
  3. {
  4.         QApplication    app(argc,argv);
  5.         QLabel  label("hello world\n");
  6.         label.show();
  7.         return  app.exec(); 
  8. }
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When I gdb the core file,I got this:
Qt Code: 
  1. #0  0x407a327c in qt_getFreetypeData () at text/qfontengine_ft.cpp:142
  2. #1  0x407a530c in qt_getFreetype () at text/qfontengine_ft.cpp:156
  3. #2  0x40656a0c in QFontDatabasePrivate::addTTFile (this=0x155e8, file=..., 
  4.     fontData=...) at text/qfontdatabase.cpp:779
  5. #3  0x40659054 in initializeDb () at text/qfontdatabase_qws.cpp:362
  6. #4  0x4065d320 in qt_qws_init_fontdb () at text/qfontdatabase_qws.cpp:506
  7. #5  0x401c4d58 in QWSServerPrivate::initServer (this=0x15d38, flags=0)
  8.     at embedded/qwindowsystem_qws.cpp:1422
  9. #6  0x401c5254 in QWSServer::QWSServer (this=0x13948, flags=0, parent=0x0)
  10.     at embedded/qwindowsystem_qws.cpp:1301
  11. #7  0x401c5434 in QWSServer::startup (flags=0)
  12.     at embedded/qwindowsystem_qws.cpp:4067
  13. #8  0x40321cc4 in qt_init (priv=0x12b58, type=2)
  14.     at kernel/qapplication_qws.cpp:2303
  15. #9  0x402365d8 in QApplicationPrivate::construct (this=0x12b58)
  16.     at kernel/qapplication.cpp:768
  17. #10 0x402378cc in QApplication::QApplication (this=0xbefebdcc, 
  18.     argc=@0xbefebdb0, argv=0xbefebe64, _internal=263680)
  19.     at kernel/qapplication.cpp:690
  20. #11 0x00008a30 in main (argc=1, argv=0xbefebe64) at hello.cpp:4
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It seems the segment fault occurred in qt_getFreetypeData () at text/qfontengine_ft.cpp:142
And then,I add printf in qt_getFreetypeData () at text/qfontengine_ft.cpp:142 to see why it's segment fault.
The original qt_getFreetypeData () is like that:
Qt Code: 
  1. QtFreetypeData *qt_getFreetypeData()
  2. {
  3.     QtFreetypeData *&freetypeData = theFreetypeData()->localData();
  4.     if (!freetypeData)
  5.         freetypeData = new QtFreetypeData;
  6.     return freetypeData;
  7. }
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After modified qt_getFreetypeData () is like that:
Qt Code: 
  1. QtFreetypeData *qt_getFreetypeData()                                    
  2. {
  3.     QtFreetypeData *&freetypeData = theFreetypeData()->localData();
  4.     if (!freetypeData)
  5.     {
  6.       printf("%s\n",__func__);
  7.       freetypeData = new QtFreetypeData;
  8.     }
  9.      return freetypeData;
  10. }
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After rebuild all,I still got a segment fault.But this time when I gdb core, I got this:
Qt Code: 
  1. #0  0x4061a768 in QFontCache::instance () at text/qfont.cpp:2589
  2. #1  0x40620014 in QFontPrivate::engineForScript (this=0x36f08, script=0)
  3.     at text/qfont.cpp:264
  4. #2  0x40646920 in QFontMetrics::height (this=0xbe8291f8)
  5.     at text/qfontmetrics.cpp:329
  6. #3  0x4090deb4 in QPlastiqueStyle::pixelMetric (this=0x37088, 
  7.     metric=QStyle::PM_TitleBarHeight, option=0xbe8291d8, widget=0x0)
  8.     at styles/qplastiquestyle.cpp:5611
  9. #4  0x401f0060 in QDecorationStyled::titleBarHeight (this=0x36810, 
  10.     widget=0xbe829db8) at embedded/qdecorationstyled_qws.cpp:84
  11. #5  0x401eb8d8 in QDecorationDefault::region (this=0x36810, 
  12.     widget=0xbe829db8, rect=..., decorationRegion=2147483647)
  13.     at embedded/qdecorationdefault_qws.cpp:421
  14. #6  0x401ef9f0 in QDecorationStyled::region (this=0x36810, 
  15.     widget=0xbe829db8, rect=..., decorationRegion=2147483647)
  16.     at embedded/qdecorationstyled_qws.cpp:298
  17. #7  0x4033694c in QWidgetPrivate::create_sys (this=0x33e40, window=0, 
  18.     initializeWindow=true) at kernel/qwidget_qws.cpp:222
  19. #8  0x402d95ec in QWidget::create (this=0xbe829db8, window=0, 
  20.     initializeWindow=true, destroyOldWindow=true) at kernel/qwidget.cpp:1318
  21. #9  0x402db47c in QWidget::setVisible (this=0xbe829db8, visible=true)
  22.     at kernel/qwidget.cpp:7329
  23. #10 0x00008c74 in QWidget::show (this=0xbe829db8)
  24.     at ../qt-lib/include/QtGui/qwidget.h:481
  25. #11 0x00008ae8 in main (argc=1, argv=0xbe829e64) at hello.cpp:6
  26. 	It seems that,when I add the printf in qt_getFreetypeData () at text/qfontengine_ft.cpp:142,
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It did not meet a segment fault in qt_getFreetypeData (),but meet segment fault after.

Now the strange thing is:
Not add printf in qt_getFreetypeData (),segment fault occurred in main->QApplication app(argc,argv)->...->qt_getFreetypeData () at text/qfontengine_ft.cpp:142
Add printf in qt_getFreetypeData (), segment fault occurred in main->label.show()->QFontCache::instance () at text/qfont.cpp:2589

I guess it is cause by Compiler optimization.
So instead of add printf, I add memory barrier in qt_getFreetypeData () to avoid wrong optimization.
Now the qt_getFreetypeData() is like this:
Qt Code: 
  1. QtFreetypeData *qt_getFreetypeData()
  2. {
  3. 	QtFreetypeData *&freetypeData = theFreetypeData()->localData();
  4. 	if (!freetypeData)
  5.     {
  6. //      printf("%s\n",__func__);
  7.         __asm__ __volatile__("":::"memory");
  8. 		freetypeData = new QtFreetypeData;
  9.     }
  10. 	return freetypeData;
  11. }
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But it is useless,it still occur segment fault in qt_getFreetypeData.

Then，I check the QFontCache::instance () at text/qfont.cpp:2589 because it cause the other segment fault.
And I found that the instance() is similar to qt_getFreetypeData().
The instance() is like this:
Qt Code: 
  1. QFontCache *QFontCache::instance()                                                    
  2. {
  3.     QFontCache *&fontCache = theFontCache()->localData();
  4.     if (!fontCache)
  5.          fontCache = new QFontCache;
  6.     return fontCache;
  7. }
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So I add printf() in instance too,like this:
Qt Code: 
  1. QFontCache *QFontCache::instance()                                                    
  2. {
  3.    QFontCache *&fontCache = theFontCache()->localData();
  4.    if (!fontCache)
  5.    {
  6.        printf("%s\n",__func__);
  7.        fontCache = new QFontCache;
  8.    }
  9.    return fontCache;
  10. }
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After add printf() in both qt_getFreetypeData() and instance(),rebuild all,no segment fault occur and i can see "hello world" on my board.
Now I want to know how can I solve segment fault without adding printf()?

This thread is so long ,thanks for read it.

Environment:

Host OS is fedora 10.

cross-compiler:
Qt Code: 
  1. [ljp@localhost hello]$ arm-vfp-linux-gnu-gcc -v
  2. Using built-in specs.
  3. Target: arm-vfp-linux-gnu
  4. Configured with: /home/usb10132/ct1/bin/targets/src/gcc-4.3.2/configure --build=i386-build_redhat-linux-gnu --host=i386-build_redhat-linux-gnu --target=arm-vfp-linux-gnu --prefix=/home/usb10132/x-tools/arm-vfp-linux-gnu --with-sysroot=/home/usb10132/x-tools/arm-vfp-linux-gnu/arm-vfp-linux-gnu/sys-root --enable-languages=c,c++ --disable-multilib --with-arch=armv5te --with-abi=atpcs --with-cpu=arm926ej-s --with-fpu=vfp --with-float=soft --with-gmp=/home/usb10132/x-tools/arm-vfp-linux-gnu --with-mpfr=/home/usb10132/x-tools/arm-vfp-linux-gnu --with-pkgversion=crosstool-NG-1.3.1 --enable-__cxa_atexit --with-local-prefix=/home/usb10132/x-tools/arm-vfp-linux-gnu/arm-vfp-linux-gnu/sys-root --disable-nls --enable-threads=posix --enable-symvers=gnu --enable-c99 --enable-long-long --enable-target-optspace
  5. Thread model: posix
  6. gcc version 4.3.2 (crosstool-NG-1.3.1)
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qmake.conf:
Qt Code: 
  1. #
  2. # qmake configuration for building with arm-linux-g++
  3. #
  4.  
  5. include(../../common/g++.conf)
  6. include(../../common/linux.conf)
  7. include(../../common/qws.conf)
  8.  
  9. # modifications to g++.conf
  10. QMAKE_CC                = arm-vfp-linux-gnu-gcc
  11. QMAKE_CXX               = arm-vfp-linux-gnu-g++
  12. QMAKE_LINK              = arm-vfp-linux-gnu-g++
  13. QMAKE_LINK_SHLIB        = arm-vfp-linux-gnu-g++
  14.  
  15. # modifications to linux.conf
  16. QMAKE_AR                = arm-vfp-linux-gnu-ar cqs
  17. QMAKE_OBJCOPY           = arm-vfp-linux-gnu-objcopy
  18. QMAKE_STRIP             = arm-vfp-linux-gnu-strip
  19.  
  20. load(qt_config)
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QT configure script
Qt Code: 
  1. ./configure -embedded arm -xplatform qws/linux-m3250 -prefix /home/ljp/qt-lib\
  2.     -qt-mouse-tslib -I/home/ljp/tslib-lib/include -L/home/ljp/tslib-lib/lib\
  3.     -nomake examples -nomake demos -no-webkit \
  4.     -no-exceptions -debug -qt-zlib \
  5.     -no-largefile -no-accessibility -no-stl -no-qt3support -no-xmlpatterns -no-phonon -no-phonon-backend \
  6.     -no-multimedia -no-javascript-jit -no-openssl -nomake docs -nomake translations -nomake tools -no-nis \
  7.     -no-pch -no-libtiff -no-xcursor -no-xfixes -no-xrandr -no-xrender -no-xkb -no-sm -no-xinerama -no-xshape \
  8.     -optimized-qmake -no-opengl -no-separate-debug-info -no-qvfb -qt-gfx-linuxfb -no-gfx-qvfb -no-kbd-qvfb \
  9.     -opensource -confirm-license -no-scripttools -no-cups -no-mouse-qvfb
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I build hello like this :
qmake -project
qmake
make

Target board is LPC3250,it has a VFP.

I have read the thread:
http://www.qtcentre.org/threads/2323...debug-quot-Qt-!
And do what it said(except change the compiler),but all useless.
can anyone help me?
Thanks again.