This plugin will "Save All" your modified documents every second (or whatever interval you choose). This was inspired by the continuous save feature in JetBrain's IDEs.
Unpack the packaged dynamic library file into the QtCreator plugins directory.
cd ~/Applications/Qt\ Creator\ 4.0.0/Qt\ Creator.app/Contents/PlugIns/
&& unzip ~/Downloads/saveallthetime-1.0.0_qtcreator-4.0.0_osx-10.11.zip
From the menubar you can toggle it with Tools > Save All The Time. If every second is too frequent for you, then set another interval from the settings panel in Preferences > Save All The Time.
Get the QtCreator source package for the version you're targeting, such as 4.0.0. Unpack it, build it, and make a test copy of the build. Start the newly built QtCreator (not the test copy). Then load the plugin .pro file, go to Projects > Run, set Executable to the test copy build of QtCreator, and then build it to generate a .dylib file. Running the plugin from the IDE will spawn your test QtCreator with the plugin loaded.
VER=4.0.0 cd /tmp
&& wget https://github.com/qtproject/qt-creator/archive/v$VER.zip
&& unzip qt-creator-$VER.zip
&& mkdir build
&& cd build
&& qmake -r ../qt*$VER
&& make -j 4
&& cp -r . ../qt-creator-$VER-test
# Now build the plugin with the build directory version of the IDE.
open ./bin/Qt\ Creator.app/Contents/MacOS/Qt\ Creator
# The executing test IDE, however, will be something like
# /tmp/qt-creator-4.0.0-test/bin/Qt Creator.app/Contents/MacOS/Qt Creator
Details on building QtCreator are at http://wiki.qt.io/Building-Qt-Creator-from-Git.
Public Domain