[Bug c++/43601] Enormous increase in DLL object files size in 4.5

["vz-gcc at zeitlins dot org" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #9 from vz-gcc at zeitlins dot org  2010-04-03 17:15 -------
Just to bring some more hard numbers into this discussion, I've installed both
4.4 and 4.5 (in addition to 3.4.5 which I'll use as a kind of baseline) on my
own machine (4/8 physical/logical CPUs, 8GB of RAM, Windows 7 64 bits). The
results of building the (main) part of wxWidgets with default configure
options excluding some third party libraries (jpeg/tiff/regex):

- With 3.4.5 (mingw-vista special r3):

% time make -sj8 wxcore
make -sj8 wxcore  30.29s user 51.71s system 46% cpu 2:55.61 total
% du -sh lib
24M lib
% du -sSh .
29M .

- With 4.4.0 (GCC):

% time make -sj8 wxcore
make -sj8 wxcore  24.50s user 43.66s system 46% cpu 2:27.97 total
% du -sh lib
29M lib
% du -sSh .
90M .

- With 4.5.0 20100311 (experimental) (GCC):

% time make -sj8 wxcore
make -sj8 wxcore  33.25s user 57.26s system 6% cpu 23:26.19 total
% du -sh lib
80M lib
% du -sSh .
554M .

- Summary of the sizes of the DLL:

% du -h */lib/wxmsw291u_core_gcc_custom.dll
9.2M    wx-mswudll-gcc3.4/lib/wxmsw291u_core_gcc_custom.dll
12M     wx-mswudll-gcc4.4/lib/wxmsw291u_core_gcc_custom.dll
47M     wx-mswudll-gcc4.5/lib/wxmsw291u_core_gcc_custom.dll


The numbers are quite clear and this is without debug information! Notice the
drastic reduction in the CPU usage for 4.5: most of the time is clearly spent
writing the files (and it's an Intel G2 SSD, things would probably be even
worse with a slower disk) and not compiling at all. And while the increase in
the size of the object files (they are mostly what makes for "du -sSh" output)
is less than what was reported before, the size of the DLLs themselves
increased as well (the previous tester couldn't report this as he didn't even
manage to link them, of course).

And while the compilation time change alone (10 times slower!) makes 4.5
unusable IMO, the change in library sizes is pretty horrible too (almost 4
times larger).

I don't know who should handle it but I don't understand how can anybody not
see that it is a real problem.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43601