cmake: link to DEBUG imported targets

AlNe

Hi,

I am using Qt on linux as provided by qt.io (opensource) and want to link to
libQt5Core.so.5.14.1.debug

I see that both the release and debug version exist:

using ls

ls -lh Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1*
-rwxr-xr-x 1 me me 6,7M Jan 23 10:42 Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1
-rw-r--r-- 1 me me  74M Jan 24 08:11 Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1.debug

using file

file Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1*

Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1:       ELF 64-bit LSB shared object, x86-64, version 1 (GNU/Linux), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=23f01ce7437f4b9ff92313b47665f63ad4606f6c, for GNU/Linux 2.6.28, not stripped

Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1.debug: ELF 64-bit LSB shared object, x86-64, version 1 (GNU/Linux), dynamically linked, interpreter *empty*, BuildID[sha1]=23f01ce7437f4b9ff92313b47665f63ad4606f6c, for GNU/Linux 2.6.28, with debug_info, not stripped

The normal cmake build, pulls in
Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1

I do not want that.
I want the power of choice, and I want to be able to choose
Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1.debug

Unfortunately the code seems to show that this is not possible:

grep -n '_populate_Core_target_properties(' Qt/5.14.1/gcc_64/lib/cmake/Qt5Core/Qt5CoreConfig.cmake

returns that Qt/5.14.1/gcc_64/lib/cmake/Qt5Core/Qt5CoreConfig.cmake only has the following (line 179)

    _populate_Core_target_properties(RELEASE "libQt5Core.so.5.14.1" "" FALSE)

This shows that only the release version Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1 is used.

Hacking and modifying the above line to the following change:

    _populate_Core_target_properties(DEBUG "libQt5Core.so.5.14.1.debug" "" FALSE)

does not work, since then compiling gives:

/usr/bin/ld: /home/me/Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1.debug: undefined reference to `ucal_clone_56'
/usr/bin/ld: /home/me/Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1.debug: undefined reference to `ucnv_close_56'
                                                           ## ... more undefined references
/usr/bin/ld: ../exes/Debug/go: no symbol version section for versioned symbol `qt_version_tag@@Qt_5.14'
/usr/bin/ld: final link failed: nonrepresentable section on output
collect2: error: ld returned 1 exit status

Checking the documentation is unfortunately disappointing on this:
https://doc.qt.io/qt-5/cmake-get-started.html#imported-targets

The documentation mentions MAP_IMPORTED_CONFIG_COVERAGE, but grepping

grep -r MAP_IMPORTED_CONFIG_COVERAGE Qt/5.14.1/gcc_64/lib/cmake

shows that this is used nowhere, so the documentation seems to be broken regarding this. Documentation says:

If your project has custom CMake build configurations, you have to map your custom configuration to either the debug or the release Qt configuration.

find_package(Qt5 COMPONENTS Core REQUIRED)

set(CMAKE_CXX_FLAGS_COVERAGE "${CMAKE_CXX_FLAGS_RELEASE} -fprofile-arcs -ftest-coverage")

# set up a mapping so that the Release configuration for the Qt imported target is
# used in the COVERAGE CMake configuration.
set_target_properties(Qt5::Core PROPERTIES MAP_IMPORTED_CONFIG_COVERAGE "RELEASE")

(Should I open a bug-repor on this via https://bugreports.qt.io/ ?)

So any tips or hints appreciated.
How can I link to the debug versions of the qt libs?
Thanks

AlNe

By the way:

ldd ~/Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1*
shows

/home/me/Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1:
	linux-vdso.so.1 (0x00007fff63ffe000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f9095f8c000)
	libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f9095d6e000)
	libicui18n.so.56 => /home/me/Qt/5.14.1/gcc_64/lib/libicui18n.so.56 (0x00007f90958d5000)
	libicuuc.so.56 => /home/me/Qt/5.14.1/gcc_64/lib/libicuuc.so.56 (0x00007f909551d000)
	libicudata.so.56 => /home/me/Qt/5.14.1/gcc_64/lib/libicudata.so.56 (0x00007f9093b3a000)
	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f9093b35000)
	libgthread-2.0.so.0 => /lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007f9093b2e000)
	libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007f9093a0f000)
	libstdc++.so.6 => /lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f909388b000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f9093708000)
	#... etc

/home/me/Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1.debug:
	not a dynamic executable

which is weird,
since file ~/Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1.debug shows

/home/me/Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1.debug: ELF 64-bit LSB shared object, x86-64, version 1 (GNU/Linux), dynamically linked, interpreter *empty*, BuildID[sha1]=23f01ce7437f4b9ff92313b47665f63ad4606f6c, for GNU/Linux 2.6.28, with debug_info, not stripped

and objdump -f ~/Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1* shows

/home/me/Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1:     file format elf64-x86-64
architecture: i386:x86-64, flags 0x00000150:
HAS_SYMS, DYNAMIC, D_PAGED
start address 0x00000000000a5780


/home/me/Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1.debug:     file format elf64-x86-64
architecture: i386:x86-64, flags 0x00000150:
HAS_SYMS, DYNAMIC, D_PAGED
start address 0x00000000000a5780

AlNe

I now think that Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1.debug are only debugging symbols. (ref)

I have not installed the sources with the online installer.
I think that if I do install the sources, I will probably be able to debug into the qt library code.
Can someone confirm this?
Thanks.

AlNe

@AlNe said in cmake: link to DEBUG imported targets:

I now think that Qt/5.14.1/gcc_64/lib/libQt5Core.so.5.14.1.debug are only debugging symbols. (ref)

I have not installed the sources with the online installer.
I think that if I do install the sources, I will probably be able to debug into the qt library code.
Can someone confirm this?
Thanks.

Nope, simply using the maintenance tool to get the sources, is not enough. I still get assembly stuff if I debug into library code such as QTimer.

AlNe

Nope, simply using the maintenance tool to get the sources, is not enough. I still get assembly stuff if I debug into library code such as QTimer.

Ok, I can now see the sources, by doing this:

Tools->Options->Debugger->General->Add Qt Sources...
and selecting
/home/me/Qt/5.14.1/Src

which results in:

Source path: /home/qt/work/qt
Target path: /home/me/Qt/5.14.1/Src