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Re: %pc relative addressing of string literals/const data
On Wed, Oct 6, 2010 at 12:13 AM, Richard Henderson <rth@redhat.com> wrote:
> On 10/05/2010 02:40 PM, Joakim Tjernlund wrote:
>> Especially one that doesn't require each function
>> to calculate the GOT address in the function prologue(why is that so?)
>
> Because PIC code can be called from non-PIC code and because
> the non-PIC code does not load the GOT address.
>
> Avoiding re-computation of the PIC register is something that
> could be done via LTO and/or cgraph optimizations. ?To my
> knowledge, no one is working on that at present.
It should be a matter of calling cgraph_only_called_directly_p ()
on the own cgraph node when expanding the GOT address calculation.
Assuming that it is preserved across all call-sites we'd retain
GOT address computation only in functions that can be called in
ways the compiler doesn't know.
Richard.
>
> r~
>