Can --gc-sections remove all the function not used?

[boerduosu]

This is my file, named xxx.c. And there are two functions in it.
void axx()
{
bxx();
}
static void bxx() //It's called by axx only , in this file.
{
...
}


When I try to compile the whole project, I used -ffunction-sections,-fdata-sections to generate the .o files, use Wl,--gc-sections -Wl,--print-gc-sections
to link to the exacutable file.

gcc 4.3.2
ld 2.18
Debian 5

After the first time I compiled it, I got a list of Removed functions. Iwas so happy.
But one second later, I rememberd that I forget to close the Compile Switch:
Debug. Then I had to recompile it and got another list.

Compare these two lists, I found that , bxx isn't on the second list.

First I guess that bxx is a debug function but never used in debug mode, and it won't be compiled in release mode .

I check the source and find that there was no compile switch for bxx........
But it's caller function axx, is removed, both the debug switch is on and off.

I try to compiled the project for several times , but the result is the same.
I can't realized it , why?

Is that the --gc-sections won't remove all the functions not used?

[Kloschüssel]

I think the static switch will do the change.

[boerduosu]

I think the static switch will do the change.

When I make the function not static, it was removed correctly by linker.

God, you're right, but WHY~~~~~~~~~???????

Obviously, it's a bug ~!!!!! Because not all the situation it won't be removed.
Please, my lord, tell me WHY?

Could this problem be fixed by any methods?

[Kloschüssel]

It's the special of _static_ methods. He can't optimize it away. Read it up in a C cookbook.

[boerduosu]

Sorry, actually, I've got a lot of static functions in Removed list.

And I have said that this function could be removed if a no related compiled switch
ebug is on.

But this is the only difference from these two compile process, it must change some situation that I don't know.

You're right ,but I can't change all the static functions to nonstatic.

So the question now is ,
① I've a lot of C cookbook, but I don't know where to find an article that mentioned if a function couldn't be automatically removed by GNU linker,then you can change the function to nonstatic,and the linker would be worked correctly.
(Could you give me a hyperlink?)
②And still I can't find an article that mentioned which situation would prevent the GNU linker to removed the unused static functions.

I know you have saved me once, I know I ask a little bit more.
But please save me to the end....
~~~Alleluia~~~