Re: [PATCH] Make gcc3.3 Eliminate Unused Static Functions

[Rusty Russell <rusty@rustcorp.com.au>]

In message <20030619121732.GQ29247@fs.tum.de> you write:
> On Fri, Jun 13, 2003 at 11:03:43AM +1000, Rusty Russell wrote:
> > Argh, bogus line pasted into Makefile turned up in patch.
> > 
> > This should be better...
> >...
> > +# Needs gcc 3.3 or above to understand max-inline-insns-auto.
> > +INLINE_OPTS	:= $(shell $(CC) -o /non/existent/file -c --param max-i
nline-insns-auto=0 -xc /dev/null 2>&1 | grep /non/existent/file >/dev/null && e
cho -finline-functions --param max-inline-insns-auto=0)
> >...
> 
> You have to add a -Wno-unused-function or you'll get a warning for every
> eliminated function.

No, suppressing warnings like that would be bad.  Instead, you write
functions like this:

	#ifdef CONFIG_FOO
	extern int register_foo(foo_fn myfunction);
	#else
	static inline int register_foo(foo_fn myfunction)
	{
		return 0;
	}
	#endif /* CONFIG_FOO */

That way, there's no unused warning, but gcc knows enough to discard
the function.

Hope that clarifies!
Rusty.
--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.