[Development] Load debug symbol from Qt library in lldb

[Ben Lau]

On 19 December 2016 at 16:07, Eike Ziller <Eike.Ziller at qt.io> wrote:

>
> > On Dec 19, 2016, at 4:10 AM, Ben Lau <xbenlau at gmail.com> wrote:
> >
> > Hi,
> >
> > I am tracking a crash problem in Qt library on Mac. First of all, I
> build a Qt 5.7.1 library from git with :
> >
> > $ ./configure  -confirm-license -developer-build -opensource -nomake
> examples -nomake tests
> >
> > Then build an example program via the the qmake built
> >
> > $ qmake CONFIG+=debug
> >
> > Run it via lldb
> >
> > $ lldb ./lodashdemo.app/Contents/MacOS/lodashdemo
> >
> > $ run
> >
> > (then crash)$ image list
> >
> > ...
> >
> > [  7] D6239705-2373-32D9-A1E9-E290DBA7CBAD 0x0000000101081000
> /Users/benlau/tmp/qt5/qt5/qtbase/lib/QtQml.framework/Versions/5/QtQml
> >
> > ....
> >
> > The QtQml is a shared library without debug symbol. The library that
> hold debug symbol should be QtQml_debug located in the same folder
> >
> > $ file  /Users/benlau/tmp/qt5/qt5/qtbase/lib/QtQml.framework/
> Versions/5/QtQml*
> >
> > /Users/benlau/tmp/qt5/qt5/qtbase/lib/QtQml.framework/Versions/5/QtQml:
>      Mach-O 64-bit dynamically linked shared library x86_64
> > /Users/benlau/tmp/qt5/qt5/qtbase/lib/QtQml.framework/Versions/5/QtQml_debug:
> Mach-O 64-bit dynamically linked shared library x86_64
> >
> > My questions are :
> >
> > 1) can I turn qmake to link the QtQml_debug ?
> > or
> >
> > 2) can I build a QtQml library with debug symbol?
>
> The “macOS” way to handle frameworks and debug builds, is that the
> application links against the non-_debug libraries, and if you want to make
> it load the debug symbols you set DYLD_IMAGE_SUFFIX=_debug before running
> the application.
>
> http://doc.qt.io/qt-5/debug.html#debugging-in-macos-and-xcode
>
> Note that applications in /usr/bin (like /usr/bin/lldb) have an additional
> safe-guard that they reset the DYLD_* variables, so you need to set it in
> lldb for the application process:
> $ lldb <your app>
> $ settings set target.env-vars DYLD_IMAGE_SUFFIX=_debug
> $ run
>
> Br,
>

Hi Eike,

It works. Thank you!
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