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Answer 1

+6 A:

The static library is a considerably different format the finished binary; partially because it has quite a bit more information. Essentially, the static library acts like a ZIP of all the .obj files generated from your translation units. This allows the linker to throw out unused functions, and if you're using LTCG, it allows the backend to make cross-module inlineing decisions and other such optimizations.

Additionally, some compilation modes will embed the debugging symbols directly in the .lib.

Generally you shouldn't need to worry about static library size; the linker will throw out all the extra information when building the final executable.

Billy ONeal 2010-07-26 04:46:10

The linker also throws out redundant and dead code, etc.

greyfade 2010-07-26 05:25:30

@greyfade: Actually the compiler does that ;)

Billy ONeal 2010-07-26 13:26:24

@Billy ONeal: At *link time*?

greyfade 2010-07-26 16:10:28

@greyfade: No, that's done at compile time, unless you use LTCG, in which case the linker is actually the compiler back end.

Billy ONeal 2010-07-26 16:14:52

@Billy ONeal: GCC produces large object files. It does no code removal, and emits nothing suitable for LTCG. (It *has* no such feature.) Binutils' `ld`, on the other hand, takes the object files and strips them of redundant and dead code while it performs relocations and linking. No LTCG in sight.

greyfade 2010-07-26 16:27:59

@greyfade: It must be doing LTCG then; it's just not calling it that. A true linker doesn't know anything about the code it's looking at other than performing function fixups.

Billy ONeal 2010-07-26 16:33:10

@Billy ONeal: They call it "garbage collection" http://sourceware.org/binutils/docs/ld/Input-Section-Keep.html#Input-Section-Keep It only knows about symbols and whether they're referenced.

greyfade 2010-07-26 16:46:31

Thanks, very informative answer.

Foglio 2010-07-26 17:00:36

@greyfade: If all it knows about are symbols, how can it remove dead code? Dead code doesn't affect symbol tables. Sure, it removes unreferenced functions, but it's not doing full DCE.

Billy ONeal 2010-07-26 17:19:24

Answer 2

+1 A:

I think that you should adjust your perceptions. Fourteen megabytes is not huge.

wilx 2010-07-26 15:07:56

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