[U-Boot] [PATCH] cmd_bdinfo: simplify local static funcs a bit

[Simon Glass]

Hi Mike,

On Mon, Oct 31, 2011 at 3:37 PM, Mike Frysinger <vapier at gentoo.org> wrote:
> On Monday 31 October 2011 17:49:58 Simon Glass wrote:
>> On Mon, Oct 31, 2011 at 2:15 PM, Tabi Timur-B04825 wrote:
>> > On Sun, Oct 30, 2011 at 7:54 PM, Mike Frysinger wrote:
>> >> -static void print_num(const char *, ulong);
>> >> +__maybe_unused
>> >> +static void print_num(const char *name, ulong value)
>> >> +{
>> >> +       printf("%-12s= 0x%08lX\n", name, value);
>> >> +}
>> >
>> > Will the linker remove the functions from the binary if they are unusued?
>>
>> If built with -ffunction-sections and --gc-sections,, then the linker
>> can do this sort of thing. Otherwise it can't, but the compiler can. I
>> just tested Mike's code on my ARM compiler to make sure and it happily
>> removed print_eth() when it was not used.
>
> i don't think you need function-sections to make this happen.  since it is
> marked "static", gcc should do DCE on it.  the __maybe_unused markings is just
> to kill off any warnings about the func not being used (which might occur in
> the #ifdef jungle below).  that attribute does not tell gcc to retain the
> function even if it isn't referenced in this file (as far as gcc can tell).
> -mike
>

That's right, you don't need function-sections for the compiler to
eliminate the code - my point was that the linker can't do this sort
of thing...luckily it doesn't need to.

There might be an option to control this, a bit like
-fkeep-static-consts, but I can't see it. Can't see it being very
useful anyway.

Regards,
Simon