[Qt-creator] gdb command line

[André Pönitz]

On Friday 05 November 2010 09:22:55 you wrote:
> On Wednesday, November 03, 2010 10:45:05 am André Pönitz wrote:
> > On Wednesday 03 November 2010 09:13:35 ext Harri Pasanen wrote:
> > > 
> > > I did have some trouble deleting that breakpoint (set on open64), but
> > > that might have been an underlying gdb issue?  (Qt Creator 2.0.1, gdb
> > > 7.1-ubuntu, on kubuntu 10.04 amd64).   Restarting gdb fixed it.
> > 
> > If just 'Delete' on the item in the Breakpoint view does not work you might
> > want to re-try with 2.1.0 beta or such.
> > 
> 
> With 2.1.81 it seemed to delete the breakpoint ok.

Good.

> > > Btw. I noticed that webkit source is not included even if I have
> > > installed Qt source.
> > 
> > Webkit source should be included, but the Webkit module is compiled without
> > debug information by default. This is intentional as it is _huge_ and
> > rarely needed unless you develop Webkit yourself.
> 
> I'm indeed trying to hunt down something that looks like a Webkit bug to me.
> And it does seem that the debug info from it gives gdb a mouthful.
> Now that I have it compiled Qt Creator periodically popped up a message saying 
> that "gdb has not responded in 20 seconds, should I wait?"  It works fine, even 
> if slowly, if I let it wait, so I increased the timeout in options.  

So it actually serves the purpose it was meant for ;-)

> This is on a reasonably modern machine 3GHz AMD Athlon(tm) II X4 640 
> Processor, 4 Gb of memory, AMD Kubuntu 10.06-64.
> Qt 4.7.1 snapshot built by yours truly, Qt Creator 2.1.81, also home-brew.
> I wonder if webkit developers just resort to prints, or compile selectively 
> only some parts with debug info...

I have really no idea. 

> Some observations:
> When I have a breakpoint inside the function "static inline int 
> qt_safe_open(const char *pathname, ...)" the pathname is show as a hex pointer 
> only.  Is there an easy way to "cast" a pointer to null terminated string if 
> this happens?

There should be entries in the context menu of this item letting you select
the display type for all items of that type, or for 'pathname' specifically.
 
> I see QUrl dumper is fixed, good!  
> 
> In trying to debug webkit I noticed that webcore.py is not Qt sources, and 
> creator does not by default understand WebCore::String and other webkit types.  
> I wonder if anyone has ready made dumpers for Qt Creator on these?

webcore.py would be of no use for Qt Creator as they use the "standard 
gdb" approach to pretty printing. They would need to be translated to
Qt Creator's dumper interface. That should be fairly straight-forward, though,
like 15 lines of python code. I'd certainly include them into Qt Creator if
they are available.
 
> Time to see if I can recompile selected modules in webkit with debug info, it 
> is really too slow now...

That's why it is disabled for general Qt application development ;-}

Thanks for the feedback,
Andre'

-- 
André Pönitz
Senior Software Engineer
Nokia, Qt Development Frameworks
 
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