[Qt-creator] Qt Creator 3.1 Slow Debugging on OS X 10.8

André Pönitz apoenitz at t-online.de
Thu May 15 00:22:45 CEST 2014

On Wed, May 14, 2014 at 01:22:14PM -0400, Michael Jackson wrote:
> I am trying out the QtCreator 3.1 release for OS X (10.8.5 with Xcode
> 5.1.1 Tooling and Xcode 5.1.1 5B1008 Command line tools) and debugging is
> extremely slow. By this I mean that I set a breakpoint in my code and it
> hits that code quickly. But then getting the "Locals and Expressions" to
> populate is another 15 seconds and then trying to scroll the list is
> another 10 seconds to start. Disclosing the "this" variable on my QWidget
> derived class takes another 10~20 seconds. THis is unbearable. I did not
> have this issue with QtCreator 3.0.1 on the same system.  I believe I
> have everything setup to use the LLDB on the "System" (/usr/bin/lldb). I
> am debugging a self built Qt 4.8.5 application. This on a 2009 Mac Pro
> with 8 Real Cores, 32GB of Ram and an SSD.
> Is this normal for this system? Is it the LLDB support? Is anyone else
> seeing this problem?

It's very likely the special support for QObject properties display. This
needs calling function in the debugged program, which is inherently slow on
any debugger backend. It's exceptionally bad for QWidget objects themselves
(not so for derived classes), as there are a lot of "owned" properties.

Since I haven't actually benchmarked with Qt 4.8.5 this might even be worse
than "expected", likely even completely failing and recovering only slowly.

Could you please open the file share/qtcreator/debugger/lldbbridge.py of
your Qt Creator installation in a text editor and change the line that reads
    staticMetaObject = self.extractStaticMetaObject(value.GetType())


    staticMetaObject = None

and check whether this makes a difference?

That should be line 1028 in that file, or close to it.


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