Re: [PATCH RFA] DWARF v2.1 64-bit support

[Michael Eager <eager at eagercon dot com>]

One small disclaimer:  Dwarf 2.1 is currently in draft status.  Changes
from Dwarf 2.0 are not complete and the specification hasn't had either 
final committee review, nor public review.  It is subject to change.

I don't anticipate that there will be changes to the 64-bit extension.  
It is possible that the version numbering for Dwarf files may change, 
perhaps if certain of the extensions are used.  

I certainly welcome real life experience with the Dwarf 2 extensions. 
Where is there a need for Dwarf sections over 4Gb?

Kevin Buettner wrote:
> 
> I request approval for committing the patch below.
> 
> I am working on a project which required me to add support for the
> DWARF version 2.1 64-bit format.  In a nutshell, the 64-bit format
> makes certain offset and length fields 64 bits wide instead of merely
> 32 bits wide, thus making it possible to have DWARF2 sections that are
> larger than 4GB in size.  (Crazy, huh?)  In order to tell which type of
> format you have, the initial length field at the beginning of certain
> sections will either have a normal 32-bit length, or an escape value
> (0xffffffff) followed by a 64 bit length.  Once you've seen one of
> these 64 bit lengths, you know that certain other fields in the same
> section (section lengths and section offsets) will also be 64-bit
> values.  Note that the initial length field with either occupy 4 or 12
> bytes while the later length and offset fields will either occupy 4 or
> 8 bytes.
> 
> The DWARF 2 draft document that I based these changes on is at:
> 
>     http://reality.sgi.com/dehnert_engr/dwarf/dwarf2p1-draft4-000720.pdf
> 

-- 
Michael Eager	 Eager Consulting     eager@eagercon.com
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