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Re: Dwarf2 FDE CIE offset

From: Richard Henderson <rth at redhat dot com>
To: gcc-bugs at gcc dot gnu dot org
Date: Sun, 9 Dec 2001 15:45:03 -0800
Subject: Re: Dwarf2 FDE CIE offset
References: <20011207194811.K28770@bubble.sa.bigpond.net.au>

On Fri, Dec 07, 2001 at 07:48:11PM +1030, Alan Modra wrote:
> Why is the dwarf2 unwind FDE CIE offset calculated as
> ". - section_start_label" while dwarf2 debug info uses
> "section_start_label - 0"?  In particular, why the sign change?

To not require a runtime relocation.

> If gcc used "section_start_label - ." instead, then the assembler could
> use a pc-relative reloc referring to .Lframe1.

True, that would also have worked.  Not all target object files
(even in elf) have pc-relative relocs though, so it seems that
you'd not really have solved the problem.

> Any hope of a change here?

No.

r~

References:
- Dwarf2 FDE CIE offset
  - From: Alan Modra

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