Zed <perrose@xxxxxx> wrote: > I've tried to make my c++ source files small in my current project. Compiling > my approx. 20 files takes very long time. I created a new source file that > just includes all my original ones with #include statements, and compiled > it. This method was much quicker. Compiling all files included in one takes > approx. double the time compared to that of compiling just one of the small > source files. So If I make a change to some header that is included by many > of the source files, the last described method that includes the files to > one is much faster. > > It seems there is a lot of compilation time overhead if the code is compiled > in many small parts - this is without taking linking into account. Is there > any settings or some trick that can reduce this overhead, except my ugly > inclusion method? > > This is the command executed per source file, created by autoconf: > > g++ -DHAVE_CONFIG_H -I. -I.. -DPACKAGE_LOCALE_DIR=\""/usr/local//locale"\" > -DPACKAGE_SRC_DIR=\""."\" -DPACKAGE_DATA_DIR=\""/usr/local/share"\" > -I/usr/include/opencv -pthread -I/usr/include/glib-2.0 > -I/usr/lib/glib-2.0/include -I/usr/include/gtk-2.0 > -I/usr/lib/gtk-2.0/include -I/usr/include/atk-1.0 -I/usr/include/cairo > -I/usr/include/pango-1.0 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include > -I/usr/include/freetype2 -I/usr/include/libpng12 -I/usr/include/pixman-1 > -I/usr/local/include/ltilib -D_GNU_SOURCE -fpic -D_DEBUG -g -O2 -MT > pick-vertex-manipulator.o -MD -MP -MF .deps/pick-vertex-manipulator.Tpo -c > -o pick-vertex-manipulator.o pick-vertex-manipulator.cpp > > Which is essentially after removing unimportant stuff: > > g++ -DHAVE_CONFIG_H -D_GNU_SOURCE -fpic -D_DEBUG -g -O2 -MT > pick-vertex-manipulator.o -MD -MP -MF .deps/pick-vertex-manipulator.Tpo -c > -o pick-vertex-manipulator.o pick-vertex-manipulator.cpp > > Thank you! I think that GCC lacks http://en.wikipedia.org/wiki/Memoization With Memoization and gcc-kernel daemon, it can compile faster bigger apps.
