gcc -ffunction-sections -Wl,--gc-sections

[Adam Goode]

On Thu, Mar 24, 2011 at 12:06, Adam Jackson <ajax at redhat.com> wrote:
> On Thu, 2011-03-24 at 15:00 +0100, Jan Kratochvil wrote:
>> Hi,
>>
>> just tried -ffunction-sections -Wl,--gc-sections on F15 xulrunner and got
>> libxul.so 24947928 -> 23631640 (5.28% gain) and it still works.
>>
>> ld.gold --icf is a different optimization but that one requires gold.
>>
>> Are there some serious Bugs why Fedora is not using it?
>
> What are the criteria for section gc?
>
> For example, if I'm the X server, I have a bunch of symbols exported
> from the binary that the drivers are expected to call, but that are
> never called from the server itself.  Does marking a function
> __attribute__((visibility("default"))) mark it as used from the garbage
> collector's perspective?
>

It is supposed to:
  "Note that when building shared libraries, the linker must assume
that any visible symbol is referenced"
  http://sourceware.org/binutils/docs/ld/Options.html


Adam