This matches the -ffunction-sections from bootstrap.pro, which tells the
compiler to create a section for each function. The -gc-sections option
tells the linker to drop what wasn't used (normally, it only drops
entire files).
Before (on Linux, built with -O3, no LTO):
text data bss dec hex filename
1746385 7920 3750 1758055 1ad367 bin/moc
1444101 6664 1894 1452659 162a73 bin/rcc
4407725 1568 4896 4414189 435aed bin/qmake
After:
text data bss dec hex filename
1131655 6520 3494 1141669 116ba5 bin/moc
1027043 5480 1766 1034289 fc831 bin/rcc
3578489 1656 5313 3585458 36b5b2 bin/qmake
Gain: 35% on moc, 28% on rcc, 19% on qmake
Before (on OS X):
__TEXT __DATA __OBJC others dec hex
1495040 12288 0 4294993008 4296500336 100176470 bin/moc
1265664 8192 0 4294983904 4296257760 10013b0e0 bin/rcc
5279744 81920 0 4297912320 4303273984 1007ec000 bin/qmake
After:
__TEXT __DATA __OBJC others dec hex
806912 8192 0 4294988132 4295803236 1000cc164 bin/moc
720896 8192 0 4294979764 4295708852 1000b50b4 bin/rcc
4841472 77824 0 4295580688 4300499984 100546c10 bin/qmake
Gain: 46% on moc, 43% on rcc, 8% on qmake.
Change-Id: Icc7cdc9fd6f5db15537b4adabaac7e7a27e539d4
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>