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Re: [IFUNC] PATCH: Add an ifunc attribute
On Thu, Jul 23, 2009 at 10:39:03AM -0700, Richard Henderson wrote:
> Not for locally defined functions, no. For 64-bit, we use
> a PC-relative reference (leaq foo(%rip),%rax), and for 32-bit
> we use a GP-relative reference (leal foo@GOTOFF(%ebx),%eax).
>
> In neither case to we read from the GOT. Not all other
> targets have that option. Indeed, the only two other targets
> I can find right away that can support this are Alpha and IA64.
> The others lack the proper relocations.
>
> (Although I'll say that for PowerPC this is a shame, since with
> an addis/addi and appropriate relocations, I suspect the number
> of relocations required for a DSO would drop considerably.)
Isn't this the same as PI_STATIC_AND_HIDDEN in glibc? If so,
S/390 and SH claim to support it also; I don't remember if
ARM does, but I know it could with existing relocations.
Not necessarily in the most optimal way, but at least by a constant
pool entry.
--
Daniel Jacobowitz
CodeSourcery