RE: optimize __gp location

From: Chen, Kenneth W <>
Date: 2005-01-22 13:20:51
Luck, Tony wrote on Friday, January 21, 2005 5:03 PM
> >-  __gp = ADDR(.got) + 0x200000;
> >+  __gp = _end - 0x200000;
> Did we used to link the ".got" section earlier?  It's after "data" now,
> but the expression used there might have made sense if ".got" was before
> the "data".
> _end - 0x200000 may work for you now, but won't this be very configuration
> dependent?  If I configure lots of drivers with "=y" option, and they
> declare lots of "bss" objects, then __gp may still be too high to reach the
> interesting data objects.
> Would an expression anchoring on the ".sdata" section be better?

I wish I can do that.  But I'm frustrated that __gp is jailed in between
GOT section and the linker symbol _end.  There are references to _end from a
couple of functions like reserve_memory(), mem_init() that compiler insist on
using gp relative to calculate value of _end.

- Ken

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Received on Fri Jan 21 21:21:04 2005

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