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Re: IA-32 gas _GLOBAL_OFFSET_TABLE_ handling bugs

From: Alan Modra <amodra at bigpond dot net dot au>
To: Roland McGrath <roland at redhat dot com>
Cc: Jakub Jelinek <jakub at redhat dot com>, binutils at sources dot redhat dot com
Date: Thu, 1 Aug 2002 11:53:17 +0930
Subject: Re: IA-32 gas _GLOBAL_OFFSET_TABLE_ handling bugs
References: <20020731152058.M20867@sunsite.ms.mff.cuni.cz> <20020801005632.GH12579@bubble.sa.bigpond.net.au> <20020731183730.K15334@redhat.sf.frob.com>

On Wed, Jul 31, 2002 at 06:37:30PM -0700, Roland McGrath wrote:
> That seems like an odd way to characterize it to me.  The meaning of .
> and of the arithmetic is perfectly sane and normal here.  What is bizarre
> is that (because of the magic symbol name) we produce a PC relative reloc
> in this instruction.  Like any PC-relative reloc, the value being computed
> is relative to the start of the instruction, but the location the reloc
> applies to is a byte or two into the instruction where the immediate sits.
> The . always means "start of this instruction", but the final value stuck
> into the immediate slot needs to account for the distance between the
> start of the instruction and the start of the immediate.

You're correct.  I spoke without thinking.

-- 
Alan Modra
IBM OzLabs - Linux Technology Centre

References:
- IA-32 gas _GLOBAL_OFFSET_TABLE_ handling bugs
  - From: Jakub Jelinek
- Re: IA-32 gas _GLOBAL_OFFSET_TABLE_ handling bugs
  - From: Alan Modra
- Re: IA-32 gas _GLOBAL_OFFSET_TABLE_ handling bugs
  - From: Roland McGrath

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