[PATCH] D17529: ELF: Implement ICF.

[Sean Silva via llvm-commits]

On Tue, Feb 23, 2016 at 2:32 PM, Rafael Espíndola <
llvm-commits at lists.llvm.org> wrote:

> > I think the "take the address" part is the crucial hint. Can't you tell
> > from the combination of visibility and relocations what functions are
> > safe to merge? The only tricky part I can imagine is identifying
> > vtables, as they do not classify as pointer leak.
>
> Somewhat. Gold has that on its list of heuristics, but it is pretty
> nasty. In particular, using files compiled with -fPIC to produce
> regular executables breaks the heuristic.
>
> Lets focus on the non-safe version for now. When time comes I think
> the correct thing to do is to implement the nop padding as it is
> always safe and then propose adding a flag to ELF to say that a
> particular section/symbol doesn't need an unique address.
>

Yeah. The compiler already knows the this information. No need for the
linker to bend over backward to try to recover it.

-- Sean Silva


>
> Cheers,
> Rafael
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