Re: [PATCH] Generic dead function optimisation

From: Alan Modra (alan@linuxcare.com.au)
Date: Thu Apr 20 2000 - 09:24:50 EST


On Thu, 20 Apr 2000, Andrew Morton wrote:

> An added bonus from this patch is that it allows ifdefs to be removed so
> that code can be always compiled, even if it's not required. This is a
> maintenance plus, preventing trivial mistakes from propagating.

Yes indeed.

> Interesting that 'ld --gc-sections' takes about 15x longer than normal.

Not that surprising. There's a lot more than 15x as many linker sections
to be processed.

> I would suggest that you make '-ffunction-sections/--gc-sections' _not_
> be the default behaviour - it's a concern that you're treading rarely
> travelled code paths through the compiler and linker. Perhaps add an
> experimental CONFIG_GC_FUNCTIONS?

No. No. Please make this the default. If you have a CONFIG option, then
you have to keep all the other ifdefs you talk about removing above.
Besides that, Grahams's patch is one of the neatest binutils tricks I've
seen for a while. Please make these code paths heavily travelled. :-)

Regards, Alan Modra

-- 
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