How to create a smaller development build of Qt 6.4?

LowLevelM

im building Qt 6.4 from source with the following commands

using this howto: https://wiki.qt.io/Building_Qt_6_from_Git

mkdir qt6_dev
cd qt6_dev
git clone git://code.qt.io/qt/qt5.git qt6
cd qt6
git checkout v6.4.0
perl init-repository
mkdir qt6-build
cd qt6-build
../qt6/configure -developer-build -opensource -nomake examples -nomake tests
cmake --build . --parallel

builds an works but it takes a while (much longer then 5.15.7) and the qt6-build folder is 53GB in size at the end

i just need boring QWidgets not QtQuick/QML, QtQuick 3D and all the other stuff like Qt Charts, QtPdf etc.

is there any way to reduce my build?

Christian Ehrlicher

@LowLevelM said in How to create a smaller development build of Qt 6.4?:

i just need boring QWidgets

Then just compoile qtbase subdir

LowLevelM

@Christian-Ehrlicher

cd qt6-build
../qt6/configure -developer-build -opensource -nomake examples -nomake tests
cd qtbase
cmake --build . --parallel

seems to work, thanks

Christian Ehrlicher

@LowLevelM said in How to create a smaller development build of Qt 6.4?:

-developer-build

Why do you need this?

LowLevelM

longterm goal:

Im porting a nearly 1Mio lines of code project from Windows to Linux (which is very much organic grown, containing many small bugs...) - thats why i want more debug information in it using -developer-build

i've alreay checked the code with ASAN but i also want to check the code with TSAN (many threads are in use, and there are hard to find race conditions in it) - which needs a from source build of Qt with TSAN

according to the docs

-DFEATURE_sanitize_thread=ON

should activate a TSAN build but sadly all my resulting Qt libs do not have any dependencies to libtsan (checked with ldd) which i think is needed

so im testing around to get it to compile with TSAN - but first i want to reduce the build time, to ease the playaround a little

this is my confgure output: https://pastebin.com/YtHmvLg2

the output contains this line - so tsan seems to be not activated

Sanitizers:
  Addresses ............................ no
  Threads .............................. no
  Memory ............................... no
  Fuzzer (instrumentation only) ........ no
  Undefined ............................ no

new problem: i saw a warning that ninja is missing and Qt is falling back to unsupported make build in the configure output
after installing ninja-build the warning was gone but now i can't build locally in the qtbase folder
giving me a error - how to build folder local when ninja is in use?

linux@linux-virtual-machine:~/dev/3rdparty-linux-gcc/qt6_dev/qt6-build/qtbase$ make
make: *** No targets specified and no makefile found.  Stop.
linux@linux-virtual-machine:~/dev/3rdparty-linux-gcc/qt6_dev/qt6-build/qtbase$ ninja
ninja: error: loading 'build.ninja': No such file or directory
linux@linux-virtual-machine:~/dev/3rdparty-linux-gcc/qt6_dev/qt6-build/qtbase$ cmake --build . --parallel 2
ninja: error: loading 'build.ninja': No such file or directory
linux@linux-virtual-machine:~/dev/3rdparty-linux-gcc/qt6_dev/qt6-build/qtbase$

the cmake --build . worked before installing ninja-build

Christian Ehrlicher

Ninja generates one big Makefile with all dependencies. If you only need QtBase then also configure only QtBase.

LowLevelM

@Christian-Ehrlicher said in How to create a smaller development build of Qt 6.4?:

If you only need QtBase then also configure only QtBase.

like this? seems to work

qt6_dev/qt6-build$ ../qt6/qtbase/configure -developer-build -opensource -nomake examples -nomake tests -sanitize thread
qt6_dev/qt6-build$ cmake --build . --parallel

the -sanitize thread also activates TSAN :)

SGaist

Hi,

Just one note, the developer-build is for hacking on Qt. If you need a debug build, just set that at configuration time.

LowLevelM

@SGaist

im now building also with -debug

i'just added the -develper-build because i though it could be of additional help when porting this organic grown project (with many small, hard to find bugs...)

The -developer-build option is not meant for shipping applications, but can be used for developing Qt. Such a build contains more exported symbols than a standard build and compiles with a higher warning level.

but yes according to the text there should be no impact for my bug hunting session