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RFH/RFC: symbol index overflow in MIPS linker stubs...

Thiemo Seufer ths@networkno.de
Thu Jun 8 18:50:00 GMT 2006 
Richard Sandiford wrote:
> David Daney <ddaney@avtrex.com> writes:
> > I think we could easily change the stubs so that they used ori (an 
> > unsigned immediate load), instead of li.  This would work for symbol 
> > tables of size up to 2^16.
> >
> > FWIW: I tested this theory by hand editing the stubs to use the unsigned 
> > immediate load and the library now runs correctly.
> >
> > A second option might be to use a two instruction sequence to load t8, 
> > but that would change the size of the stubs.  I don't know if that would 
> > be portable or possible.
> 
> I'm with Daniel (if I've understood him correctly): I think it _is_
> worth going the extra mile and only using the longer stubs if the
> largest dynindx requires it.

Thinking again about it, currently the stub fits in a cacheline, so
there might be a bigger performance impact than I estimated before.
IOW, I agree.

[snip]
> I'm a little worried that using longer stubs might confuse the native
> IRIX tools, but I no longer have access to IRIX, so I can't check.
> I don't think that's a problem for the cases that really need it --
> what else can we do? -- but I think it is one reason to prefer the
> traditional stubs when possible.

Probably some IRIX user is interested in testing the patch.

Thiemo
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