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LLDB requires a large amount of resources on QtCreator



  • Hi all,

    I have a problem using LLDB with QtCreator. Basically, when I set a breakpoint and the program stops, the lldb process occupies the 100% of the CPU, the temperature of my pc increases and this makes me impossible to debug using QtCreator.

    The problem does not occur when using lldb with a command line.
    The problem occurs with any program, even with

    int main() {
      int var = 1;
      var = var + 7; // set a breakpoint here
    
      return 0;
    }
    

    The problem occurs with QMake projects, CMake projects and custom projects (Makefile and C compiler).

    I have found a thread with a user experiencing my same exact problem:
    https://lists.qt-project.org/pipermail/qt-creator/2015-September/004969.html
    But my ~/.config/QtProject/QtCreator.ini occupies 25kb and I don't have any error message in the Debugger Log.

    I am using a MacBook Pro with macOS Catalina 10.15.2 (but I faced the same problem with Mojave some weeks ago), QtCreator v4.10.1.

    Do you have any suggestion to investigate more deeply the problem? Do you think that reinstalling lldb or QtCreator could solve the issue?


  • Lifetime Qt Champion

    @francl after a short search I only found https://bugreports.qt.io/browse/QTCREATORBUG-22955 but that seems unrelated.

    Can you post your debugger log (Windows > Views)?

    Which Xcode version do you use?

    Regards



  • @aha_1980 thanks for your help. Actually the problem reported in the link you provided is not exactly the same as mine. But I have found some other users experiencing this problem in another places:
    https://www.mail-archive.com/qt-creator@qt-project.org/msg07920.html
    https://bugreports.qt.io/browse/QTCREATORBUG-23336

    My Xcode version is 11.3.1, the debugger log, referring to the small program I wrote in the main post (same breakpoint) is:

    Setting up inferior...
    1loadDumpers({"token":1})
    
    2executeDebuggerCommand({"command":"settings append target.source-map /Users/qt/work/qt /Users/francl/Qt/5.12.5/clang_64/../Src","token":2})
    
    3setupInferior({"attachpid":0,"breakonmain":0,<environment suppressed>,"executable":"/Users/francl/Desktop/build-main-Desktop_Qt_5_12_5_clang_64bit-Debug/main.app/Contents/MacOS/main","nativemixed":0,"platform":"","processargs":"","remotechannel":"","startmode":1,"sysroot":"","token":3,"useterminal":0,"workingdirectory":"/Users/francl/Desktop/build-main-Desktop_Qt_5_12_5_clang_64bit-Debug/main.app/Contents/MacOS"})
    
    Running requested...
    4runEngine({"token":4})
    
    
    ERROR: Lldb stderr: warning: (x86_64) /Users/francl/Qt/5.12.5/clang_64/lib/QtGui.framework/Versions/5/QtGui empty dSYM file detected, dSYM was created with an executable with no debug info.
    
    ERROR: Lldb stderr: warning: (x86_64) /Users/francl/Qt/5.12.5/clang_64/lib/QtCore.framework/Versions/5/QtCore empty dSYM file detected, dSYM was created with an executable with no debug info.
    
    
    5insertBreakpoint({"address":0,"command":"","condition":"","enabled":1,"expression":"","file":"/Users/francl/Desktop/test/main.cpp","function":"","id":"","ignorecount":0,"line":167,"modelid":1,"oneshot":0,"token":5,"type":1})
    
    Running.
    
    Stopped.
    6fetchThreads({"token":6})
    
    
    7fetchStack({"context":"","nativemixed":0,"stacklimit":20,"token":7})
    
    
    8activateFrame({"index":0,"thread":"11045","token":8})
    
    9fetchVariables({"autoderef":1,"context":"","displaystringlimit":"100","dyntype":1,"expanded":["inspect","watch","return","local"],"fancy":1,"formats":{},"nativemixed":0,"partialvar":"","passexceptions":0,"qobjectnames":1,"stringcutoff":"10000","timestamps":0,"token":9,"typeformats":{},"watchers":[]})
    
    
    
    <Rebuild Watchmodel 1 @ 09:29:08.314 >
    Run requested...
    10continueInferior({"token":10})
    
    Running.
    
    Debugger finished.
    

  • Lifetime Qt Champion

    Hi @francl,

    Ok, it then looks like QTCREATORBUG-23336 - should be fixed for 4.11.1.

    Regards



  • @aha_1980 thanks for you help, with 4.11.1 everything goes fine!


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