Dynamic symbol table

[Karl Vogel]

Karl Vogel wrote:

> I noticed that a lot of the .so files have big dynamic symbol tables, as
> if everything is exported. Wouldn't it be better to only export the
> symbols that are really required?!

Seems like it is indeed not needed. I've changed the Makefile.am of 
some kcm modules to use a version script which only exports init_* 
and create_* symbols. 

ie. kdebase/kcontrol/arts/Makefile.am

--- Makefile.am.orig    2004-07-15 22:57:34.848230768 +0200
+++ Makefile.am 2004-07-15 22:26:47.000000000 +0200
@@ -2,7 +2,7 @@

 kcm_arts_la_SOURCES = arts.cpp generaltab.ui hardwaretab.ui

-kcm_arts_la_LDFLAGS  = $(all_libraries) -module -avoid-version -no-undefined
+kcm_arts_la_LDFLAGS  = $(all_libraries) -module -avoid-version -no-undefined -Wl,--version-script=export.ver
 kcm_arts_la_LIBADD = $(LIB_KIO) $(LIB_KUTILS) -lkmid

 INCLUDES = -I$(kde_includes)/arts  $(all_includes)


And I put an export.ver file in the arts directory. The file contents is:

$ cat export.ver
{
        global: init_*; create_*;
        local: *;
};


After this change the symbol table is nicely reduced to 2 symbols (down from 
96 symbols):

$ objdump -CT .libs/kcm_arts.so|grep -v UND|grep DF
00008bb0 g    DF .text  00000254  Base        init_arts
00009bc0 g    DF .text  0000008e  Base        create_arts

Filesize also benefits from it:

After:
$ ls -l .libs/kcm_arts.so
-rwxrwxr-x  1 kvo kvo 395815 Jul 15 22:39 .libs/kcm_arts.so

Before:
$ ls -l .libs/kcm_arts.so
-rwxrwxr-x  1 kvo kvo 400039 Jul 15 23:00 .libs/kcm_arts.so


The more symbols, the more diskspace is saved ofcourse.. ie:

before:
$ ls -l .libs/kcm_kwindecoration.so
-rwxrwxr-x  1 kvo kvo 609527 Jul 10 01:19 .libs/kcm_kwindecoration.so

after:
$ ls -l .libs/kcm_kwindecoration.so
-rwxrwxr-x  1 kvo kvo 586391 Jul 15 23:03 .libs/kcm_kwindecoration.so



KDE Startup time however isn't reduced.. still 18 seconds for a cold boot..
while only 5 seconds for a warm start :-(