[SOLVED] Problems with debugging (GDB on Linux with QtCreator)

bobhairgrove

My QtCreator is version 3.2.0, my Qt is 5.3.1 and my g++ is 4.9.0.
GDB version is 7.8.1, Python version is 2.7.3.
OS is Ubuntu 12.04 LTS.

According to the documentation, this should work OK. However, I cannot figure out how to display locals in the Expression pane. I can highlight a variable and choose "Add Expression Evaluator" from the menu. The name of the variable shows up, but it always has "<no such value>" in the Value column.

Single-stepping works OK, as do breakpoints, but QtCreator doesn't want to step into C library functions even though the source code is part of the project. How can I step into those?

This is rather frustrating, to say the least.

bobhairgrove

Apparently, since I compiled GDB myself, there is no Python embedded in it ... however, Python is installed in Ubuntu.

Do I need to recompile GDB with Python? I didn't see any options to do that when I built GDB.

bobhairgrove

OK, I went back and did "make clean" and "make distclean" and reconfigured GDB --with-python after installing the python development files, then rebuilt and installed it.

Although I can run GDB and do

@(gdb) python print sys.version@

and it works in the terminal, QtCreator still doesn't display any local variables with their values. It is the same behavior as before.

Thanks for any ideas.

bobhairgrove

Following up in the above matter, here is the output when I run the debugger (sorry if it is rather long, I have to split it up into four different messages):

PART 1:

@dATTEMPT SYNC

sStarting debugger "GdbEngine" for ABI "x86-linux-generic-elf-64bit"...
dStart parameters: 'test_csv' mode: 1
dABI: x86-linux-generic-elf-64bit
dLanguages: c++
dExecutable: /home/bob/code/Qt/test_csv/build-test_csv-Desktop_Qt_5_3_GCC_64bit-Debug/test_csv [terminal]
dDirectory: /home/bob/code/Qt/test_csv/build-test_csv-Desktop_Qt_5_3_GCC_64bit-Debug
dDebugger: /usr/bin/gdb
dProject: /home/bob/code/Qt/test_csv/test_csv (built: /home/bob/code/Qt/test_csv/build-test_csv-Desktop_Qt_5_3_GCC_64bit-Debug)
dQML server: 127.0.0.1:3768
dRemote: :0
dSysroot:
dDebug Source Location:
dDebugger settings:
dQmlInspector.ShowAppOnTop: false (default: false)
dQmlInspector.FromQml: false (default: false)
dNoPluginBreakpoints: false (default: false)
dSelectedPluginBreakpointsPattern: .* (default: .*)
dBreakOnThrow: false (default: false)
dBreakOnCatch: false (default: false)
dBreakOnWarning: false (default: false)
dBreakOnFatal: false (default: false)
dBreakOnAbort: false (default: false)
dShowQmlObjectTree: true (default: true)
dDisplayStringLimit: 100 (default: 100)
dListSourceFiles: false (default: false)
dSkipKnownFrames: false (default: false)
dEnableReverseDebugging: false (default: false)
dAllPluginBreakpoints: true (default: true)
dSelectedPluginBreakpoints: false (default: false)
dAdjustBreakpointLocations: true (default: true)
dMaximalStackDepth: 20 (default: 20)
dShowStandardNamespace: true (default: true)
dShowQtNamespace: true (default: true)
dSortStructMembers: true (default: true)
dAutoDerefPointers: true (default: true)
dMaximalStringLength: 10000 (default: 10000)
dWatchdogTimeout: 20 (default: 20)
dAutoEnrichParameters: true (default: true)
dUseDynamicType: true (default: true)
dTargetAsync: false (default: false)
dWarnOnReleaseBuilds: true (default: true)
dMultiInferior: false (default: false)
dIntelFlavor: false (default: false)
dIdentifyDebugInfoPackages: false (default: false)
dCDB_Console: false (default: false)
dBreakpointCorrection: true (default: true)
dIgnoreFirstChanceAccessViolation: false (default: false)
dLoadGdbInit: true (default: true)
dLoadGdbDumpers1: true (default: true)
dAttemptQuickStart: false (default: false)
dGdbStartupCommands: (default: )
dGdbPostAttachCommands: (default: )
dAlwaysAdjustColumnWidths: true (default: true)
dExtraDumperFile: (default: )
dGdbCustomDumperCommands: (default: )
dAdditionalArguments: (default: )
dSymbolPaths: (default: )
dSourcePaths: (default: )
dBreakEvent: (default: )
dBreakOnCrtDbgReport: false (default: false)
dShowThreadNames: false (default: false)
dUseToolTips: false (default: true) ***
dUseToolTipsInLocalsView: false (default: false)
dUseToolTipsInBreakpointsView: false (default: false)
dUseToolTipsInBreakpointsView: false (default: true) ***
dUseAddressInBreakpointsView: false (default: false)
dUseAddressInStackView: false (default: false)
dCloseBuffersOnExit: false (default: false)
dSwitchModeOnExit: false (default: false)
dBreakpointsFullPath: false (default: false)
dRaiseOnInterrupt: true (default: true)
dStationaryEditorWhileStepping: false (default: false)
dUseDebuggingHelper: true (default: true)
dUseCodeModel: true (default: true)
dUseAlternatingRowColours: false (default: false)
dFontSizeFollowsEditor: false (default: false)
dUseMessageBoxForSignals: true (default: true)
dAutoQuit: false (default: false)
dLogTimeStamps: false (default: false)
dVerboseLog: false (default: false)
dState changed from DebuggerNotReady(0) to EngineSetupRequested(1) [master]
dQUEUE: SETUP ENGINE
dCALL: SETUP ENGINE
dEXAMINING /home/bob/code/Qt/test_csv/build-test_csv-Desktop_Qt_5_3_GCC_64bit-Debug/test_csv
dELF SECTIONS: .interp .note.ABI-tag .hash .dynsym .dynstr .gnu.version .gnu.version_r .rela.dyn .rela.plt .init .plt .text .fini .rodata .eh_frame_hdr .eh_frame .gcc_except_table .init_array .fini_array .jcr .data.rel.ro .dynamic .got .got.plt .data .bss .comment .debug_aranges .debug_info .debug_abbrev .debug_line .debug_str .debug_ranges .shstrtab .symtab .strtab
dTRYING TO START ADAPTER
@

bobhairgrove

PART 2:

@

dENABLING TEST CASE: 0
dSTARTING /usr/bin/gdb -i mi
dGDB STARTED, INITIALIZING IT
<1show version
<2show debug-file-directory
<3set print object on
<4set breakpoint pending on
<5set print elements 10000
<6handle SIGSEGV nopass stop print
<7set unwindonsignal on
<8set width 0
<9set height 0
sSetting up inferior...
<10set substitute-path /var/tmp/qt-src /home/bob/Qt-5.3.1/5.3/gcc_64
<11-interpreter-exec console "set auto-solib-add on"
<12-interpreter-exec console "python sys.path.insert(1, '/home/bob/Qt-5.3.1/Tools/QtCreator/share/qtcreator/debugger/')"
<13-interpreter-exec console "python sys.path.append('/usr/bin/data-directory/python')"
<14-interpreter-exec console "python from gdbbridge import *"

=thread-group-added,id="i1"
~"GNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2.1) 7.4-2012.04\n"
~"Copyright (C) 2012 Free Software Foundation, Inc.\n"
~"License GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html\nThis is free software: you are free to change and redistribute it.\nThere is NO WARRANTY, to the extent permitted by law. Type "show copying"\nand "show warranty" for details.\n"
~"This GDB was configured as "x86_64-linux-gnu".\nFor bug reporting instructions, please see:\n"
~"http://bugs.launchpad.net/gdb-linaro/.\n"

&"show version\n"
~"GNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2.1) 7.4-2012.04\n"
~"Copyright (C) 2012 Free Software Foundation, Inc.\n"
~"License GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html\nThis is free software: you are free to change and redistribute it.\nThere is NO WARRANTY, to the extent permitted by law. Type "show copying"\nand "show warranty" for details.\n"
~"This GDB was configured as "x86_64-linux-gnu".\nFor bug reporting instructions, please see:\n"
~"http://bugs.launchpad.net/gdb-linaro/.\n"
1^done
dPARSING VERSION: 1^done
dSUPPORTED GDB VERSION GNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2.1) 7.4-2012.04
dCopyright (C) 2012 Free Software Foundation, Inc.
dLicense GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html
dThis is free software: you are free to change and redistribute it.
dThere is NO WARRANTY, to the extent permitted by law. Type "show copying"
dand "show warranty" for details.
dThis GDB was configured as "x86_64-linux-gnu".
dFor bug reporting instructions, please see:
dhttp://bugs.launchpad.net/gdb-linaro/.
dGNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2.1) 7.4-2012.04
dCopyright (C) 2012 Free Software Foundation, Inc.
dLicense GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html
dThis is free software: you are free to change and redistribute it.
dThere is NO WARRANTY, to the extent permitted by law. Type "show copying"
dand "show warranty" for details.
dThis GDB was configured as "x86_64-linux-gnu".
dFor bug reporting instructions, please see:
dhttp://bugs.launchpad.net/gdb-linaro/.
dUSING GDB VERSION: 70400, BUILD: 2012
<15-interpreter-exec console "set target-async off"

&"show debug-file-directory\n"
~"The directory where separate debug symbols are searched for is "/usr/lib/debug".\n"
2^done

&"set print object on\n"
3^done

&"set breakpoint pending on\n"
4^done

&"set print elements 10000\n"
5^done

&"handle SIGSEGV nopass stop print\n"
~"Signal Stop\tPrint\tPass to program\tDescription\n"
~"SIGSEGV Yes\tYes\tNo\t\tSegmentation fault\n"
6^done

&"set unwindonsignal on\n"
7^done

&"set width 0\n"
8^done

&"set height 0\n"
9^done

&"set substitute-path /var/tmp/qt-src /home/bob/Qt-5.3.1/5.3/gcc_64\n"
10^done

11^done

12^done

13^done
@

bobhairgrove

PART 3:

@
/* ... lots snipped ...*/

dENGINE SUCCESSFULLY STARTED
dNOTE: ENGINE SETUP OK
dState changed from EngineSetupRequested(1) to EngineSetupOk(3) [master]
dQUEUE: SETUP INFERIOR
dState changed from EngineSetupOk(3) to InferiorSetupRequested(4) [master]
dQUEUE: SETUP INFERIOR

15^done

dCALL: SETUP INFERIOR
dTaking notice of pid 4450
Going to attach to 4450
sSetting breakpoints...
dSetting breakpoints...
dATTEMPT BREAKPOINT SYNCHRONIZATION
dTAKING OWNERSHIP OF BREAKPOINT 1 IN STATE 0
<16-break-insert -f ""main.cpp":44"
dBREAKPOINTS ARE NOT FULLY SYNCHRONIZED

&"No symbol table is loaded. Use the "file" command.\n"
16^done,bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="<PENDING>",pending="\"main.cpp":44",times="0",original-location="\"main.cpp":44"}
dATTEMPT BREAKPOINT SYNCHRONIZATION
dBREAKPOINTS ARE SYNCHRONIZED
dALL COMMANDS DONE; INVOKING CALLBACK
dNOTE: INFERIOR SETUP OK
dState changed from InferiorSetupRequested(4) to InferiorSetupOk(6) [master]
dState changed from InferiorSetupOk(6) to EngineRunRequested(7) [master]
dQUEUE: RUN ENGINE

dCALL: RUN ENGINE
<17attach 4450
dATTEMPT SYNC
dATTEMPT BREAKPOINT SYNCHRONIZATION
dBREAKPOINT SYNCHRONIZATION NOT POSSIBLE IN CURRENT STATE

&"attach 4450\n"
~"Attaching to process 4450\n"
=thread-group-started,id="i1",pid="4450"
sThread group i1 created
=thread-created,id="1",group-id="i1"
sThread 1 created
~"Reading symbols from /home/bob/code/Qt/test_csv/build-test_csv-Desktop_Qt_5_3_GCC_64bit-Debug/test_csv..."
sReading /home/bob/code/Qt/test_csv/build-test_csv-Desktop_Qt_5_3_GCC_64bit-Debug/test_csv......
~"done.\n"
=breakpoint-modified,bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="0x0000000000401e57",file="../test_csv/main.cpp",fullname="/home/bob/code/Qt/test_csv/test_csv/main.cpp",line="44",times="0",original-location="\\"main.cpp\":44"}
=library-loaded,id="/lib64/ld-linux-x86-64.so.2",target-name="/lib64/ld-linux-x86-64.so.2",host-name="/lib64/ld-linux-x86-64.so.2",symbols-loaded="0",thread-group="i1"
sLibrary /lib64/ld-linux-x86-64.so.2 loaded
~"Reading symbols from /lib64/ld-linux-x86-64.so.2..."
sReading /lib64/ld-linux-x86-64.so.2......
~"(no debugging symbols found)...done.\n"
~"Loaded symbols for /lib64/ld-linux-x86-64.so.2\n"
~"0x00007f4595d8e6b0 in ?? () from /lib64/ld-linux-x86-64.so.2\n"
*stopped,frame={addr="0x00007f4595d8e6b0",func="??",args=[],from="/lib64/ld-linux-x86-64.so.2"},thread-id="1",stopped-threads="all",core="3"
dNOTE: INFERIOR STOP OK
sStopped.
dState changed from EngineRunRequested(7) to InferiorStopOk(14) [master]
<18importPlainDumpers
sStopped.
17^done
@

bobhairgrove

PART 4:

@
dINFERIOR ATTACHED
dNOTE: ENGINE RUN AND INFERIOR STOP OK
sStopped.
dState changed from InferiorStopOk(14) to InferiorStopOk(14) [master]
dNOTE: INFERIOR RUN REQUESTED
sRun requested...
dState changed from InferiorStopOk(14) to InferiorRunRequested(10) [master]
sRunning requested...
<19-exec-continue

<20-thread-info

&"importPlainDumpers\n"
~"None\n"
18^done

19^running
dNOTE: INFERIOR RUN OK
sRunning.
dState changed from InferiorRunRequested(10) to InferiorRunOk(11) [master]
*running,thread-id="all"
dNOTE: INFERIOR STILL RUNNING IN STATE InferiorRunOk.

*stopped,reason="signal-received",signal-name="SIGSTOP",signal-meaning="Stopped (signal)",frame={addr="0x00007f4595d8e6b0",func="??",args=[],from="/lib64/ld-linux-x86-64.so.2"},thread-id="1",stopped-threads="all",core="3"
dNOTE: INFERIOR SPONTANEOUS STOP
sStopped.
dState changed from InferiorRunOk(11) to InferiorStopOk(14) [master]
INTERNAL CONTINUE AFTER SIGSTOP FROM STUB
dNOTE: INFERIOR RUN REQUESTED
sRun requested...
dState changed from InferiorStopOk(14) to InferiorRunRequested(10) [master]
sRunning requested...
<21-exec-continue

20^done,threads=[{id="1",target-id="process 4450",name="test_csv",frame={level="0",addr="0x00007f4595d8e6b0",func="??",args=[],from="/lib64/ld-linux-x86-64.so.2"},state="stopped",core="3"}],current-thread-id="1"
<22-stack-list-frames 0 20

21^running
dNOTE: INFERIOR RUN OK
sRunning.
dState changed from InferiorRunRequested(10) to InferiorRunOk(11) [master]
*running,thread-id="all"
dNOTE: INFERIOR STILL RUNNING IN STATE InferiorRunOk.

*stopped,reason="signal-received",signal-name="SIGSTOP",signal-meaning="Stopped (signal)",frame={addr="0x00007f4595d8e6b0",func="??",args=[],from="/lib64/ld-linux-x86-64.so.2"},thread-id="1",stopped-threads="all",core="2"
dNOTE: INFERIOR SPONTANEOUS STOP
sStopped.
dState changed from InferiorRunOk(11) to InferiorStopOk(14) [master]
INTERNAL CONTINUE AFTER SIGSTOP FROM STUB
dNOTE: INFERIOR RUN REQUESTED
sRun requested...
dState changed from InferiorStopOk(14) to InferiorRunRequested(10) [master]
sRunning requested...
<23-exec-continue

22^done,stack=[frame={level="0",addr="0x00007f4595d8e6b0",func="??",from="/lib64/ld-linux-x86-64.so.2"},frame={level="1",addr="0x0000000000000001",func="??"},frame={level="2",addr="0x00007fffe26fa9b4",func="??"},frame={level="3",addr="0x0000000000000000",func="??"}]

23^running
dNOTE: INFERIOR RUN OK
sRunning.
dState changed from InferiorRunRequested(10) to InferiorRunOk(11) [master]
*running,thread-id="all"
dNOTE: INFERIOR STILL RUNNING IN STATE InferiorRunOk.

=library-loaded,id="/usr/local/lib64/libstdc++.so.6",target-name="/usr/local/lib64/libstdc++.so.6",host-name="/usr/local/lib64/libstdc++.so.6",symbols-loaded="0",thread-group="i1"
sLibrary /usr/local/lib64/libstdc++.so.6 loaded
=library-loaded,id="/lib/x86_64-linux-gnu/libm.so.6",target-name="/lib/x86_64-linux-gnu/libm.so.6",host-name="/lib/x86_64-linux-gnu/libm.so.6",symbols-loaded="0",thread-group="i1"
sLibrary /lib/x86_64-linux-gnu/libm.so.6 loaded
=library-loaded,id="/usr/local/lib64/libgcc_s.so.1",target-name="/usr/local/lib64/libgcc_s.so.1",host-name="/usr/local/lib64/libgcc_s.so.1",symbols-loaded="0",thread-group="i1"
sLibrary /usr/local/lib64/libgcc_s.so.1 loaded
=library-loaded,id="/lib/x86_64-linux-gnu/libc.so.6",target-name="/lib/x86_64-linux-gnu/libc.so.6",host-name="/lib/x86_64-linux-gnu/libc.so.6",symbols-loaded="0",thread-group="i1"
sLibrary /lib/x86_64-linux-gnu/libc.so.6 loaded

=breakpoint-modified,bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="0x0000000000401e57",file="../test_csv/main.cpp",fullname="/home/bob/code/Qt/test_csv/test_csv/main.cpp",line="44",times="1",original-location="\\"main.cpp\":44"}
*stopped,reason="breakpoint-hit",disp="keep",bkptno="1",frame={addr="0x0000000000401e57",func="main",args=[],file="../test_csv/main.cpp",fullname="/home/bob/code/Qt/test_csv/test_csv/main.cpp",line="44"},thread-id="1",stopped-threads="all",core="4"
dNOTE: INFERIOR SPONTANEOUS STOP
sStopped.
dState changed from InferiorRunOk(11) to InferiorStopOk(14) [master]
sStopped at breakpoint 1 (1) in thread 1.

<24-thread-info

24^done,threads=[{id="1",target-id="process 4450",name="test_csv",frame={level="0",addr="0x0000000000401e57",func="main",args=[],file="../test_csv/main.cpp",fullname="/home/bob/code/Qt/test_csv/test_csv/main.cpp",line="44"},state="stopped",core="4"}],current-thread-id="1"
<25-stack-list-frames 0 20

25^done,stack=[frame={level="0",addr="0x0000000000401e57",func="main",file="../test_csv/main.cpp",fullname="/home/bob/code/Qt/test_csv/test_csv/main.cpp",line="44"}]
<26-stack-select-frame 0
<27bb options:fancy,autoderef,dyntype vars: expanded:local,return,watch,inspect typeformats: formats: watchers: stringcutoff:10000 displaystringlimit:100

26^done

&"bb options:fancy,autoderef,dyntype vars: expanded:local,return,watch,inspect typeformats: formats: watchers: stringcutoff:10000 displaystringlimit:100\n"
~"data=[],typeinfo=[]\n"
~"None\n"
27^done
<Rebuild Watchmodel 1>
sFinished retrieving data

@

bobhairgrove

This bit in the above output:

@GNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2.1) 7.4-2012.04\n"@

is strange, because when I run GDB from the console, I get this:

I have two versions of GDB installed, one in /usr/bin and the other in /usr/local/bin. Both GDB's give me 7.8.1 when I run them from the terminal.

Hmmm...

bobhairgrove

OK ... I went to the Projects view, clicked on "Build & Run", then "Manage Kits", cloned the auto-detected "Desktop Qt 5.3" kit, then made sure that the GDB in /usr/local/bin was selected, then clicked on "Make Default" at the right.

BINGO!! :))

Now everything is working as it should, and I see 7.8.1 for the GDB version in the debugging output at the top.