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Large data sections support

H. J. Lu hjl@lucon.org
Mon Jun 13 07:11:00 GMT 2005 
On Sun, Jun 12, 2005 at 10:17:21PM -0700, Richard Henderson wrote:
> On Sun, Jun 12, 2005 at 09:16:51PM -0700, H. J. Lu wrote:
> > I guess I may have missed may details. Could someone please point
> > me to the information why .ldata/.lbss/.lrodata are needed?
> 
> We use rip-relative access to most data.  This has a 32-bit
> signed offset.  If you want to support more than 2GB worth
> of static data, you need to use a different addressing mode.
> 
> In order to not penalize the entire application, some data is
> still accessed via 32-bit offsets (the bits in .data).  Thus
> we need a way to separate the data that's accessed via 64-bit
> operations and those accessed via 32-bit operations.

So it is different from small data/normal data on ia64, which is a GP
issue. If it is the case, all large data sections have to come after
the normal data sections. Otherwise, some data in the normal data
section may be out of reach via 32bit offsets. Am I correct?

Have we considered mixing normal definition/common and large
definition/common as well as the related relocations?


H.J.
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