cvs commit: src/sbin/init init.c

[Christoph Mallon]

Kostik Belousov wrote:
> On Sun, Sep 28, 2008 at 12:55:42PM -0700, Xin LI wrote:
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA1
>>
>> Kostik Belousov wrote:
>>> On Sat, Sep 27, 2008 at 12:09:10AM +0000, Xin LI wrote:
>>>> delphij     2008-09-27 00:09:10 UTC
>>>>
>>>>   FreeBSD src repository
>>>>
>>>>   Modified files:
>>>>     sbin/init            init.c 
>>>>   Log:
>>>>   SVN rev 183391 on 2008-09-27 00:09:10Z by delphij
>>>>   
>>>>   Static-ify procedures in init(8).
>>>>   
>>>>   Revision  Changes    Path
>>>>   1.66      +79 -79    src/sbin/init/init.c
>>> What is a reason for the change ?
>> This would reduce the size of generated binary...
> 
> I am quite curious. Could you, please, show the numbers.
> Is the reduction in size is due to function inlining, or it is purely
> symbol table size issue ?

If a function or variable can be made static, it should be. There is 
basically not excuse not to do so. In fact, it is considered a design 
flaw of C, that symbols default to external linkage instead of internal 
by default. The compiler can do more optimisations on things, it knows 
it is the only user of. For example it can change the calling convention 
of functions to pass parameters in registers instead of on the stack, if 
it knows all callers. If a function is not static, it must assume there 
are callers, which it has not control of. Changing the calling 
convention is just one example of possible optimisations. Further it 
reduces the chances of name clashes with functions local to other 
translation units.

Regards
	Christoph