What is R_X86_64_GOTPLT64 used for?
Mon Nov 17 14:05:00 GMT 2014
On Thu, 13 Nov 2014, H.J. Lu wrote:
> @GOTPLT will create a PLT entry, but it doesn't mean PLT entry will be
Correct. The compiler was supposed to somehow make a good decision (e.g.
if there were calls and address-takings in the same unit).
> Only @PLTOFF will use PLT entry. Linker should be smart enough to use
> only one GOT slot, regardless if @GOTPLT or @GOT is used to take
> function address and call via PLT.
For @GOT the respective GOT slot needs to resolve to the final address (to
provide stable function pointers). For @GOTPLT it could at first resolve
to the PLT slot (which would be only a relative reloc, not a symbol based
one), like Richard said. So there still would be a difference. Apart
from that I agree that the linker should ideally only use one GOT slot,
which would remove that particular advantage of @GOTPLT (note that it
doesn't do so currently contrary to what you said downthread, I'll respond
> I'd like to propose
> 1. Update psABI to remove R_X86_64_GOTPLT64.
I don't have much against this, but would like others to say something.
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