Incomplete function signatures in backtrace with Qt built using `-g1` flag

[alvinhochun]

Hi, this is an issue which I'm not sure where the problem is. The current Krita nightly builds on https://binary-factory.kde.org/job/Krita_Nightly_Windows_Build/ uses llvm-mingw 20220323, with dependencies (Qt included) built with the -g1 flag for line number tables debugging info only. When doing backtrace, Some Qt functions shows incomplete function names (class names stripped) and missing argument types.

To check with lldb you need a build with https://reviews.llvm.org/D126367 included. First extract the binary zip, then extract the -dbg.zip package inside it. Set a breakpoint at KisMainWindow::showAboutApplication, then run and choose from the menu "Help -> About Krita" to trigger the breakpoint.

With gdb:

Click to expand

D:\temp>D:\dev\toolchain\mingw\x86_64-11.2.0-release-posix-seh-rt_v9-rev1\bin\gdb.exe C:\Users\Alvin\Downloads\krita-nightly-x64-5.1.0-prealpha-b123708256\bin\krita.exe
[...]
(gdb) b KisMainWindow::showAboutApplication
Function "KisMainWindow::showAboutApplication" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (KisMainWindow::showAboutApplication) pending.
(gdb) r
Starting program: C:\Users\Alvin\Downloads\krita-nightly-x64-5.1.0-prealpha-b123708256\bin\krita.exe
[...]
Thread 1 hit Breakpoint 1, KisMainWindow::showAboutApplication (this=0x2117be1ba70)
    at C:/Packaging/workspace/Krita_Nightly_Windows_Build/krita/libs/ui/KisMainWindow.cpp:2695
2695    C:/Packaging/workspace/Krita_Nightly_Windows_Build/krita/libs/ui/KisMainWindow.cpp: No such file or directory.
(gdb) bt
#0  KisMainWindow::showAboutApplication (this=0x2117be1ba70)
    at C:/Packaging/workspace/Krita_Nightly_Windows_Build/krita/libs/ui/KisMainWindow.cpp:2695
#1  0x00007ffc442cea08 in activate ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\corelib\kernel/qobject.cpp:3804
#2  0x00007ffc442cea08 in activate ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\corelib\kernel/qobject.cpp:3804
#3  0x00007ffc4abf3a42 in activate ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\widgets\kernel/qaction.cpp:1166
#4  0x00007ffc4ad61898 in activateCausedStack ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\widgets\widgets/qmenu.cpp:1356
#5  0x00007ffc4ad5f031 in activateAction ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\widgets\widgets/qmenu.cpp:1433
#6  0x00007ffc4ac34362 in event () at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\widgets\kernel/qwidget.cpp:8967
#7  0x00007ffc4ad66149 in event () at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\widgets\widgets/qmenu.cpp:3070
#8  0x00007ffc4abfc756 in notify_helper ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\widgets\kernel/qapplication.cpp:3650
#9  0x00007ffc4abff42c in notify ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\widgets\kernel/qapplication.cpp:3110
#10 0x00007ffc533019e8 in KisApplication::notify (this=0xa01c9cf758, receiver=0x2110a58fc40, event=0xa01c9cba40)
    at C:/Packaging/workspace/Krita_Nightly_Windows_Build/krita/libs/ui/KisApplication.cpp:758
#11 0x00007ffc442a1353 in notifyInternal2 ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\corelib\kernel/qcoreapplication.cpp:1088
#12 0x00007ffc4abfd041 in sendMouseEvent ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\widgets\kernel/qapplication.cpp:2648
#13 0x00007ffc4ac52766 in handleMouseEvent ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\widgets\kernel/qwidgetwindow.cpp:570
#14 0x00007ffc4ac50e28 in event ()
--Type <RET> for more, q to quit, c to continue without paging--
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\widgets\kernel/qwidgetwindow.cpp:293
#15 0x00007ffc4abfc756 in notify_helper ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\widgets\kernel/qapplication.cpp:3650
#16 0x00007ffc4abfd96e in notify ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\widgets\kernel/qapplication.cpp:3005
#17 0x00007ffc533019e8 in KisApplication::notify (this=0xa01c9cf758, receiver=0x2110b67c540, event=0xa01c9cbf40)
    at C:/Packaging/workspace/Krita_Nightly_Windows_Build/krita/libs/ui/KisApplication.cpp:758
#18 0x00007ffc442a1353 in notifyInternal2 ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\corelib\kernel/qcoreapplication.cpp:1088
#19 0x00007ffc496f034a in processMouseEvent ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\gui\kernel/qguiapplication.cpp:2167
#20 0x00007ffc496d8f5b in sendWindowSystemEvents ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\gui\kernel/qwindowsysteminterface.cpp:1157
#21 0x00007ffc442f32e3 in qt_internal_proc ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\corelib\kernel/qeventdispatcher_win.cpp:248
#22 0x00007ffca48ce7e8 in USER32!CallWindowProcW () from C:\WINDOWS\System32\user32.dll
#23 0x00007ffca48ce229 in USER32!DispatchMessageW () from C:\WINDOWS\System32\user32.dll
#24 0x00007ffc442f47c3 in processEvents ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\corelib\kernel/qeventdispatcher_win.cpp:642
#25 0x00007ffc577231e5 in QWindowsGuiEventDispatcher::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\platformsupport\eventdispatchers/qwindowsguieventdispatcher.cpp:74
#26 0x00007ffc4429e195 in processEvents ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\corelib\kernel/qeventloop.cpp:138
#27 exec () at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\corelib\kernel/qeventloop.cpp:225
#28 0x00007ffc442a19cd in exec ()
    at C:\Packaging\KritaDepsBuild\ext_qt\s\qtbase\src\corelib\kernel/qcoreapplication.cpp:1389
--Type <RET> for more, q to quit, c to continue without paging--
#29 0x00007ffc53f857b7 in krita_main (argc=<optimized out>, argv=0x2117094efb0)
    at C:/Packaging/workspace/Krita_Nightly_Windows_Build/krita/krita/main.cc:717
#30 0x00007ff7020f13d7 in __tmainCRTStartup () at ../crt/crtexe.c:321
#31 0x00007ff7020f1156 in WinMainCRTStartup () at ../crt/crtexe.c:176

With lldb:

Click to expand

D:\temp>C:\Users\Alvin\Downloads\lldb_test\lldb.exe C:\Users\Alvin\Downloads\krita-nightly-x64-5.1.0-prealpha-b123708256\bin\krita.exe
(lldb) target create "C:\\Users\\Alvin\\Downloads\\krita-nightly-x64-5.1.0-prealpha-b123708256\\bin\\krita.exe"
(lldb) Current executable set to 'C:\Users\Alvin\Downloads\krita-nightly-x64-5.1.0-prealpha-b123708256\bin\krita.exe' (x86_64).
(lldb) b KisMainWindow::showAboutApplication
Breakpoint 1: where = libkritaui.dll`KisMainWindow::showAboutApplication() + 13 at KisMainWindow.cpp:2695:25, address = 0x0000000180524fcd
(lldb) r
Process 26716 launched: 'C:\Users\Alvin\Downloads\krita-nightly-x64-5.1.0-prealpha-b123708256\bin\krita.exe' (x86_64)
Process 26716 stopped
* thread #1, stop reason = breakpoint 1.1
    frame #0: 0x00007ffc53354fcd libkritaui.dll`KisMainWindow::showAboutApplication(this=0x000001da7a6d0880) at KisMainWindow.cpp:2695:25
(lldb) bt
* thread #1, stop reason = breakpoint 1.1
  * frame #0: 0x00007ffc53354fcd libkritaui.dll`KisMainWindow::showAboutApplication(this=0x000001da7a6d0880) at KisMainWindow.cpp:2695:25
    frame #1: 0x00007ffc442cea08 Qt5Core.dll`::activate() at qobject.cpp:3804:21
    frame #2: 0x00007ffc5a584636 libkritawidgetutils.dll`KisKHelpMenu::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) [inlined] KisKHelpMenu::showAboutApplication(this=<unavailable>) at moc_khelpmenu.cpp:174:5 [artificial]
    frame #3: 0x00007ffc442cea08 Qt5Core.dll`::activate() at qobject.cpp:3804:21
    frame #4: 0x00007ffc4abf3a42 Qt5Widgets.dll`::activate() at qaction.cpp:0
    frame #5: 0x00007ffc4ad61898 Qt5Widgets.dll`::activateCausedStack() at qmenu.cpp:1356:17
    frame #6: 0x00007ffc4ad5f031 Qt5Widgets.dll`::activateAction() at qmenu.cpp:1433:5
    frame #7: 0x00007ffc4ac34362 Qt5Widgets.dll`::event() at qwidget.cpp:8967:9
    frame #8: 0x00007ffc4ad66149 Qt5Widgets.dll`::event() at qmenu.cpp:3070:21
    frame #9: 0x00007ffc4abfc756 Qt5Widgets.dll`::notify_helper() at qapplication.cpp:3650:26
    frame #10: 0x00007ffc4abff42c Qt5Widgets.dll`::notify() at qapplication.cpp:3110:30
    frame #11: 0x00007ffc533019e8 libkritaui.dll`KisApplication::notify(this=0x0000002df74ff318, receiver=0x000001da095c1300, event=0x0000002df74fb600) at KisApplication.cpp:758:40
    frame #12: 0x00007ffc442a1353 Qt5Core.dll`::notifyInternal2() at qcoreapplication.cpp:1088:18
    frame #13: 0x00007ffc4abfd041 Qt5Widgets.dll`::sendMouseEvent() at qapplication.cpp:2648:22
    frame #14: 0x00007ffc4ac52766 Qt5Widgets.dll`::handleMouseEvent() at qwidgetwindow.cpp:570:17
    frame #15: 0x00007ffc4ac50e28 Qt5Widgets.dll`::event() at qwidgetwindow.cpp:293:9
    frame #16: 0x00007ffc4abfc756 Qt5Widgets.dll`::notify_helper() at qapplication.cpp:3650:26
    frame #17: 0x00007ffc4abfd96e Qt5Widgets.dll`::notify() at qapplication.cpp:0
    frame #18: 0x00007ffc533019e8 libkritaui.dll`KisApplication::notify(this=0x0000002df74ff318, receiver=0x000001da0a43efe0, event=0x0000002df74fbb00) at KisApplication.cpp:758:40
    frame #19: 0x00007ffc442a1353 Qt5Core.dll`::notifyInternal2() at qcoreapplication.cpp:1088:18
    frame #20: 0x00007ffc496f034a Qt5Gui.dll`::processMouseEvent() at qguiapplication.cpp:2167:5
    frame #21: 0x00007ffc496d8f5b Qt5Gui.dll`::sendWindowSystemEvents() at qwindowsysteminterface.cpp:1157:13
    frame #22: 0x00007ffc442f32e3 Qt5Core.dll`::qt_internal_proc() at qeventdispatcher_win.cpp:248:16
    frame #23: 0x000000018000e7e8 user32.dll`CallWindowProcW + 1016
    frame #24: 0x000000018000e229 user32.dll`DispatchMessageW + 601
    frame #25: 0x00007ffc442f47c3 Qt5Core.dll`::processEvents() at qeventdispatcher_win.cpp:642:21
    frame #26: 0x00007ffc577231e5 qwindows.dll`qt_plugin_instance at qwindowsguieventdispatcher.cpp:74:44
    frame #27: 0x00007ffc4429e195 Qt5Core.dll`::exec() [inlined] processEvents at qeventloop.cpp:138:51
    frame #28: 0x00007ffc4429e177 Qt5Core.dll`::exec() at qeventloop.cpp:225:9
    frame #29: 0x00007ffc442a19cd Qt5Core.dll`::exec() at qcoreapplication.cpp:1389:32
    frame #30: 0x00007ffc53f857b7 krita.dll`krita_main + 17287
    frame #31: 0x00007ff7020f13d7 krita.exe`__tmainCRTStartup at crtexe.c:321:15
    frame #32: 0x00007ff7020f1156 krita.exe`WinMainCRTStartup at crtexe.c:176:9
    frame #33: 0x00007ffca5047034 kernel32.dll`BaseThreadInitThunk + 20
    frame #34: 0x00007ffca66c2651 ntdll.dll`RtlUserThreadStart + 33

For example, the activate function in qobject.cpp:3804 is supposed to be QMetaObject::activate and the one in qaction.cpp should be QAction::activate.

Code inside Krita is built with -g and contains proper function signatures.

In contrast, this is what it would look like without debug info (it uses the export table names if I haven't mistaken):

Click to expand

(lldb) bt
* thread #1, stop reason = breakpoint 1.1
  * frame #0: 0x00007ffc4adb4fc0 libkritaui.dll`KisMainWindow::showAboutApplication()
    frame #1: 0x00007ffc442cea08 Qt5Core.dll`QMetaObject::activate(QObject*, int, int, void**) + 2136
    frame #2: 0x00007ffc442cea08 Qt5Core.dll`QMetaObject::activate(QObject*, int, int, void**) + 2136
    frame #3: 0x00007ffc52ae3a42 Qt5Widgets.dll`QAction::activate(QAction::ActionEvent) + 210
    frame #4: 0x00007ffc52c51898 Qt5Widgets.dll`QMenu::setIcon(QIcon const&) + 5848
    frame #5: 0x00007ffc52c4f031 Qt5Widgets.dll`QMenu::internalDelayedPopup() + 2257
    frame #6: 0x00007ffc52b24362 Qt5Widgets.dll`QWidget::event(QEvent*) + 1522
    frame #7: 0x00007ffc52c56149 Qt5Widgets.dll`QMenu::event(QEvent*) + 1049
    frame #8: 0x00007ffc52aec756 Qt5Widgets.dll`QApplicationPrivate::notify_helper(QObject*, QEvent*) + 262
    frame #9: 0x00007ffc52aef42c Qt5Widgets.dll`QApplication::notify(QObject*, QEvent*) + 7340
    frame #10: 0x00007ffc4ad619e8 libkritaui.dll`KisApplication::notify(QObject*, QEvent*) + 168
    frame #11: 0x00007ffc442a1353 Qt5Core.dll`QCoreApplication::notifyInternal2(QObject*, QEvent*) + 147
    frame #12: 0x00007ffc52aed041 Qt5Widgets.dll`QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool, bool) + 897
    frame #13: 0x00007ffc52b42766 Qt5Widgets.dll`QDesktopWidget::qt_metacall(QMetaObject::Call, int, void**) + 12934
    frame #14: 0x00007ffc52b40e28 Qt5Widgets.dll`QDesktopWidget::qt_metacall(QMetaObject::Call, int, void**) + 6472
    frame #15: 0x00007ffc52aec756 Qt5Widgets.dll`QApplicationPrivate::notify_helper(QObject*, QEvent*) + 262
    frame #16: 0x00007ffc52aed96e Qt5Widgets.dll`QApplication::notify(QObject*, QEvent*) + 494
    frame #17: 0x00007ffc4ad619e8 libkritaui.dll`KisApplication::notify(QObject*, QEvent*) + 168
    frame #18: 0x00007ffc442a1353 Qt5Core.dll`QCoreApplication::notifyInternal2(QObject*, QEvent*) + 147
    frame #19: 0x00007ffc435f034a Qt5Gui.dll`QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) + 3018
    frame #20: 0x00007ffc435d8f5b Qt5Gui.dll`QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 235
    frame #21: 0x00007ffc442f32e3 Qt5Core.dll`QEventDispatcherWin32Private::activateEventNotifier(QWinEventNotifier*) + 771
    frame #22: 0x00007ffca48ce7e8 user32.dll`CallWindowProcW + 1016
    frame #23: 0x00007ffca48ce229 user32.dll`DispatchMessageW + 601
    frame #24: 0x00007ffc442f47c3 Qt5Core.dll`QEventDispatcherWin32::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 1987
    frame #25: 0x00007ffc58b731e5 qwindows.dll`qt_plugin_instance + 11173
    frame #26: 0x00007ffc4429e195 Qt5Core.dll`QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 485
    frame #27: 0x00007ffc442a19cd Qt5Core.dll`QCoreApplication::exec() + 109
    frame #28: 0x00007ffc530357b7 krita.dll`krita_main + 17287
    frame #29: 0x00007ff7020f13d7 krita.exe`__tmainCRTStartup + 631
    frame #30: 0x00007ff7020f1156 krita.exe`.l_startw + 18
    frame #31: 0x00007ffca5047034 kernel32.dll`BaseThreadInitThunk + 20
    frame #32: 0x00007ffca66c2651 ntdll.dll`RtlUserThreadStart + 33

I tried to make a small self-contained example, but that doesn't show the issue, so I am not quite sure if it is really caused by the use of -g1. I also have not tried doing this build with GCC to see how it behaves (I can try but it will take a few hours and some disk space...)

[alvinhochun]

Okay, now I have a self-contained example:

Makefile:

Click to expand

CXX=D:\dev\toolchain\llvm-mingw\llvm-mingw-20220323-ucrt-x86_64\bin\clang++.exe
# CXX=D:\dev\toolchain\mingw\x86_64-11.2.0-release-posix-seh-rt_v9-rev1\bin\g++.exe

all: main.exe

dog.dll: dog.cpp dog.h Makefile
	$(CXX) -shared -DDOG_DLL -O3 -g1 -o $@ -Wl,--exclude-all-symbols -Wl,--out-implib,lib$@.a $<

dog.dll.a: dog.dll Makefile

main.exe: main.cpp dog.h dog.dll.a dog.dll Makefile
	$(CXX) -g -O2 -o $@ $< -L. -ldog

dog.h:

Click to expand

#include <functional>

#ifdef DOG_DLL
#   define DOG_DLLIMPORT __declspec(dllexport)
#else
#   define DOG_DLLIMPORT __declspec(dllimport)
#endif

struct DOG_DLLIMPORT Dog {
    void bark();
    void bark(int n);

    static void register_bark_callback(std::function<void(const char *)> callback);
};

dog.cpp:

Click to expand

#include "dog.h"

static std::function<void(const char *)> g_bark_callback;

void Dog::register_bark_callback(std::function<void(const char *)> callback) {
    g_bark_callback = callback;
}

void Dog::bark() {
    g_bark_callback("Woof");
}

void Dog::bark(const int n) {
    for (int i = 0; i < n; i++) {
        g_bark_callback("Woof");
    }
}

main.cpp:

Click to expand

#include "dog.h"

#include <cstdio>

void bark_to_stdout(const char *msg) {
    puts(msg);
}

int main() {
    Dog::register_bark_callback(bark_to_stdout);

    Dog dog;
    dog.bark(10);
    dog.bark();

    return 0;
}

Build with mingw32-make.

When built with Clang:

(lldb) b bark_to_stdout
Breakpoint 1: where = main.exe`bark_to_stdout(char const*) at main.cpp:6:5, address = 0x0000000140001470
(lldb) r
Process 18560 launched: 'D:\temp\dlltest\main.exe' (x86_64)
Process 18560 stopped
* thread #1, stop reason = breakpoint 1.1
    frame #0: 0x00007ff7f5da1470 main.exe`bark_to_stdout(msg="Woof") at main.cpp:6:5
   3    #include <cstdio>
   4
   5    void bark_to_stdout(const char *msg) {
-> 6        puts(msg);
   7    }
   8
   9    int main() {
(lldb) bt
* thread #1, stop reason = breakpoint 1.1
  * frame #0: 0x00007ff7f5da1470 main.exe`bark_to_stdout(msg="Woof") at main.cpp:6:5
    frame #1: 0x00007ffc8cb3152a dog.dll`::bark() [inlined] operator() at function.h:507:16
    frame #2: 0x00007ffc8cb31515 dog.dll`::bark() [inlined] operator() at function.h:1184:12
    frame #3: 0x00007ffc8cb31515 dog.dll`::bark() at dog.cpp:15:9
    frame #4: 0x00007ff7f5da14ea main.exe`main at main.cpp:13:9
    frame #5: 0x00007ff7f5da13d7 main.exe`__tmainCRTStartup at crtexe.c:321:15
    frame #6: 0x00007ff7f5da1436 main.exe`mainCRTStartup at crtexe.c:202:9
    frame #7: 0x00007ffca5047034 kernel32.dll`BaseThreadInitThunk + 20
    frame #8: 0x00007ffca66c2651 ntdll.dll`RtlUserThreadStart + 33

Note that Dog::bark(int) jsut shows up as ::bark().

When built with g++:

(lldb) b bark_to_stdout
Breakpoint 1: where = main.exe`bark_to_stdout(char const*) at main.cpp:6:9, address = 0x0000000140001540
(lldb) r
Process 19920 launched: 'D:\temp\dlltest\main.exe' (x86_64)
Process 19920 stopped
* thread #1, stop reason = breakpoint 1.1
    frame #0: 0x00007ff705c41540 main.exe`bark_to_stdout(msg="Woof") at main.cpp:6:9
   3    #include <cstdio>
   4
   5    void bark_to_stdout(const char *msg) {
-> 6        puts(msg);
   7    }
   8
   9    int main() {
(lldb) bt
error: dog.dll {0x00000817}: DIE has DW_AT_ranges(DW_FORM_sec_offset 0x6d) attribute, but range extraction failed (invalid range list offset 0x6d), please file a bug and attach the file at the start of this error message
error: dog.dll {0x00000817}: DIE has DW_AT_ranges(DW_FORM_sec_offset 0x6d) attribute, but range extraction failed (invalid range list offset 0x6d), please file a bug and attach the file at the start of this error message
error: main.exe {0x00002c9c}: DIE has DW_AT_ranges(DW_FORM_sec_offset 0x2c) attribute, but range extraction failed (invalid range list offset 0x2c), please file a bug and attach the file at the start of this error message
error: main.exe {0x00002d02}: DIE has DW_AT_ranges(DW_FORM_sec_offset 0x3f) attribute, but range extraction failed (invalid range list offset 0x3f), please file a bug and attach the file at the start of this error message
error: main.exe {0x00002c9c}: DIE has DW_AT_ranges(DW_FORM_sec_offset 0x2c) attribute, but range extraction failed (invalid range list offset 0x2c), please file a bug and attach the file at the start of this error message
* thread #1, stop reason = breakpoint 1.1
  * frame #0: 0x00007ff705c41540 main.exe`bark_to_stdout(msg="Woof") at main.cpp:6:9
    frame #1: 0x00007ffc8cb31506 dog.dll`Dog::bark(int) at std_function.h:560:9
    frame #2: 0x00007ff705c428c5 main.exe`main at main.cpp:13:13
    frame #3: 0x00007ff705c413a5 main.exe`__tmainCRTStartup + 533
    frame #4: 0x00007ff705c414f6 main.exe
    frame #5: 0x00007ffca5047034 kernel32.dll`BaseThreadInitThunk + 20
    frame #6: 0x00007ffca66c2651 ntdll.dll`RtlUserThreadStart + 33

[mstorsjo]

Thanks! And for the minimal repro, I presume that a binary built with Clang gets the correct backtrace if inspected with gdb, just like in the original testcase?

[alvinhochun]

Actually gdb also doesn't show the class name:

(gdb) bt
#0  bark_to_stdout (msg=0x7ffc8cb33048 <refptr..xi_z+8> "Woof") at main.cpp:6
#1  0x00007ffc8cb3152a in operator() () at D://dev/toolchain/llvm-mingw/llvm-mingw-20220323-ucrt-x86_64/include/c++/v1/__functional/function.h:507
#2  operator() () at D://dev/toolchain/llvm-mingw/llvm-mingw-20220323-ucrt-x86_64/include/c++/v1/__functional/function.h:1184
#3  bark () at dog.cpp:15
#4  0x00007ff647ab14ea in main () at main.cpp:13

[alvinhochun]

I found that adding -fdebug-info-for-profiling makes the backtrace better for the repro:

(lldb) bt
* thread #1, stop reason = breakpoint 1.1
  * frame #0: 0x00007ff7c97d1470 main.exe`bark_to_stdout(msg="Woof") at main.cpp:6:5
    frame #1: 0x00007ffc98a7152a dog.dll`Dog::bark(int) [inlined] std::__1::__function::__value_func<void (char const*)>::operator()(char const*&&) const at function.h:507:16
    frame #2: 0x00007ffc98a71515 dog.dll`Dog::bark(int) [inlined] std::__1::function<void (char const*)>::operator()(char const*) const at function.h:1184:12
    frame #3: 0x00007ffc98a71515 dog.dll`Dog::bark(int) at dog.cpp:15:9
    frame #4: 0x00007ff7c97d14ea main.exe`main at main.cpp:13:9
    frame #5: 0x00007ff7c97d13d7 main.exe`__tmainCRTStartup at crtexe.c:321:15
    frame #6: 0x00007ff7c97d1436 main.exe`mainCRTStartup at crtexe.c:202:9
    frame #7: 0x00007ffca5047034 kernel32.dll`BaseThreadInitThunk + 20
    frame #8: 0x00007ffca66c2651 ntdll.dll`RtlUserThreadStart + 33

I'll try it out with the Qt build and report back.

[alvinhochun]

Great! It adds about 65 MB to the debug info (+3.7%), but the backtrace is now much more readable:

Click to expand

(lldb) bt
* thread #1, stop reason = breakpoint 1.1
  * frame #0: 0x00007ffc4c83c819 libkritaui.dll`KisMainWindow::showAboutApplication(this=0x000001ebb0fa4ba0) at KisMainWindow.cpp:2697:5
    frame #1: 0x00007ffc56cf0868 Qt5Core.dll`QMetaObject::activate(QObject*, int, int, void**) at qobject.cpp:3804:21
    frame #2: 0x00007ffc5c244956 libkritawidgetutils.dll`KisKHelpMenu::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) [inlined] KisKHelpMenu::showAboutApplication(this=<unavailable>) at moc_khelpmenu.cpp:174:5 [artificial]
    frame #3: 0x00007ffc56cf0868 Qt5Core.dll`QMetaObject::activate(QObject*, int, int, void**) at qobject.cpp:3804:21
    frame #4: 0x00007ffc5b473a42 Qt5Widgets.dll`QAction::activate(QAction::ActionEvent) at qaction.cpp:0
    frame #5: 0x00007ffc5b5e3468 Qt5Widgets.dll`QMenuPrivate::activateCausedStack(QVector<QPointer<QWidget>> const&, QAction*, QAction::ActionEvent, bool) at qmenu.cpp:1356:17
    frame #6: 0x00007ffc5b5e0c01 Qt5Widgets.dll`QMenuPrivate::activateAction(QAction*, QAction::ActionEvent, bool) at qmenu.cpp:1433:5
    frame #7: 0x00007ffc5b4b42d2 Qt5Widgets.dll`QWidget::event(QEvent*) at qwidget.cpp:8967:9
    frame #8: 0x00007ffc5b5e7d19 Qt5Widgets.dll`QMenu::event(QEvent*) at qmenu.cpp:3070:21
    frame #9: 0x00007ffc5b47c716 Qt5Widgets.dll`QApplicationPrivate::notify_helper(QObject*, QEvent*) at qapplication.cpp:3650:26
    frame #10: 0x00007ffc5b47f3ed Qt5Widgets.dll`QApplication::notify(QObject*, QEvent*) at qapplication.cpp:3110:30
    frame #11: 0x00007ffc4c7e9218 libkritaui.dll`KisApplication::notify(this=0x000000e7790ff788, receiver=0x000001ebc1928250, event=0x000000e7790fba70) at KisApplication.cpp:758:40
    frame #12: 0x00007ffc56cc3323 Qt5Core.dll`QCoreApplication::notifyInternal2(QObject*, QEvent*) at qcoreapplication.cpp:1088:18
    frame #13: 0x00007ffc5b47d001 Qt5Widgets.dll`QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool, bool) at qapplication.cpp:2648:22
    frame #14: 0x00007ffc5b4d2836 Qt5Widgets.dll`QWidgetWindow::handleMouseEvent(QMouseEvent*) at qwidgetwindow.cpp:570:17
    frame #15: 0x00007ffc5b4d0ef8 Qt5Widgets.dll`QWidgetWindow::event(QEvent*) at qwidgetwindow.cpp:293:9
    frame #16: 0x00007ffc5b47c716 Qt5Widgets.dll`QApplicationPrivate::notify_helper(QObject*, QEvent*) at qapplication.cpp:3650:26
    frame #17: 0x00007ffc5b47d92e Qt5Widgets.dll`QApplication::notify(QObject*, QEvent*) at qapplication.cpp:0
    frame #18: 0x00007ffc4c7e9218 libkritaui.dll`KisApplication::notify(this=0x000000e7790ff788, receiver=0x000001ebc1a60d00, event=0x000000e7790fbf68) at KisApplication.cpp:758:40
    frame #19: 0x00007ffc56cc3323 Qt5Core.dll`QCoreApplication::notifyInternal2(QObject*, QEvent*) at qcoreapplication.cpp:1088:18
    frame #20: 0x00007ffc4bc7fdf1 Qt5Gui.dll`QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) at qguiapplication.cpp:2167:5
    frame #21: 0x00007ffc4bc68e5b Qt5Gui.dll`QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) at qwindowsysteminterface.cpp:1157:13
    frame #22: 0x00007ffc56d15093 Qt5Core.dll`qt_internal_proc(HWND__*, unsigned int, unsigned long long, long long) at qeventdispatcher_win.cpp:248:16
    frame #23: 0x000000018000e7e8 user32.dll`CallWindowProcW + 1016
    frame #24: 0x000000018000e229 user32.dll`DispatchMessageW + 601
    frame #25: 0x00007ffc56d1659b Qt5Core.dll`QEventDispatcherWin32::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) at qeventdispatcher_win.cpp:642:21
    frame #26: 0x00007ffc58b73795 qwindows.dll`QWindowsGuiEventDispatcher::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) at qwindowsguieventdispatcher.cpp:74:44
    frame #27: 0x00007ffc56cc0175 Qt5Core.dll`QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) [inlined] QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) at qeventloop.cpp:138:51
    frame #28: 0x00007ffc56cc0157 Qt5Core.dll`QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) at qeventloop.cpp:225:9
    frame #29: 0x00007ffc56cc399d Qt5Core.dll`QCoreApplication::exec() at qcoreapplication.cpp:1389:32
    frame #30: 0x00007ffc5c3857b7 krita.dll`::krita_main(argc=<unavailable>, argv=0x000001eba9094cb0) at main.cc:718:17
    frame #31: 0x00007ff66a0313d7 krita.com`__tmainCRTStartup at crtexe.c:321:15
    frame #32: 0x00007ff66a031436 krita.com`mainCRTStartup at crtexe.c:202:9
    frame #33: 0x00007ffca5047034 kernel32.dll`BaseThreadInitThunk + 20
    frame #34: 0x00007ffca66c2651 ntdll.dll`RtlUserThreadStart + 33

I guess it comes down to different expectations. In GCC -g1 means: "produces minimal information, enough for making backtraces in parts of the program that you don’t plan to debug. This includes descriptions of functions and external variables, and line number tables, but no information about local variables." But in Clang -g1 is aliased to -gline-tables-only which I guess does not include full function signatures?

[mstorsjo]

But in Clang -g1 is aliased to -gline-tables-only which I guess does not include full function signatures?

Sorry, no idea about that - but it sounds true, if both gdb and lldb get roughly the same amount of information from the binary.