From david.moore@intel.com  Wed Feb 23 14:35:04 2011
From: david.moore@intel.com (Moore, David)
Date: Wed, 23 Feb 2011 07:35:04 -0700
Subject: [Dwarf-Discuss] question about [0x0..0xffffffff] location list
	entry
Message-ID: <3BA20DF9B35F384F8B7395B001EC3FB38A348629@azsmsx507.amr.corp.intel.com>

Making it invalid is, I think, no better a choice than allowing it to wrap. Suppose a routine is positioned right at the end of memory. The last address of a range could then quite validly be 0xffffffff + 1. We can represent that using a base and offset - the start of the routine and its length, perhaps.

So ends of ranges that are just bigger than the size of memory are conceivable and if we specify how arithmetic works here, we should say it uses universals (in the Ada sense)

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From davea42@earthlink.net  Wed Feb 23 16:51:38 2011
From: davea42@earthlink.net (David Anderson)
Date: Wed, 23 Feb 2011 08:51:38 -0800
Subject: [Dwarf-Discuss] question about [0x0..0xffffffff] location list
 entry
In-Reply-To: <3BA20DF9B35F384F8B7395B001EC3FB38A348629@azsmsx507.amr.corp.intel.com>
References: <3BA20DF9B35F384F8B7395B001EC3FB38A348629@azsmsx507.amr.corp.intel.com>
Message-ID: <4D653B1A.3000004@earthlink.net>

On 02/23/2011 06:35 AM, Moore, David wrote:
> So ends of ranges that are just bigger than the size of memory are 
> conceivable and if we specify how arithmetic works here, we should say 
> it uses universals (in the Ada sense)

Or we could just admit the last byte (addressable unit) of memory cannot 
necessarily  be attributed correctly
and leave it at that.   (Meaning the range end of 0xffffffff, need not 
allow +1 in loclist ranges in
32bit-offset-dwarf, etc).

This seems to me to be a restriction (and simplification) of no 
practical detriment. And it means
existing documentation (of DWARF) remains correct.

We already restrict the size of 32bit offset DWARF sections so they 
cannot necessarily use the last few bytes
of a section  (the 64bit extension stuff, Section 7.4 in DWARF3/4) as 
that was deemed harmless.

DavidA.




From davea42@earthlink.net  Wed Feb 23 16:59:55 2011
From: davea42@earthlink.net (David Anderson)
Date: Wed, 23 Feb 2011 08:59:55 -0800
Subject: [Dwarf-Discuss] question about [0x0..0xffffffff] location list
 entry
In-Reply-To: <4D653B1A.3000004@earthlink.net>
References: <3BA20DF9B35F384F8B7395B001EC3FB38A348629@azsmsx507.amr.corp.intel.com>
	<4D653B1A.3000004@earthlink.net>
Message-ID: <4D653D0B.9050901@earthlink.net>

On 02/23/2011 08:51 AM, David Anderson wrote:
>
> Or we could just admit the last byte (addressable unit) of memory 
> cannot necessarily  be attributed correctly
> and leave it at that.   (Meaning the range end of 0xffffffff, need not 
> allow +1 in loclist ranges in
> 32bit-offset-dwarf, etc).
>
Well, I conflated offset with address-range in the above sentence, but 
nevertheless I guess
it is obvious I  think DWARF does not need to handle that last byte 
perfectly.

DavidA.

-- 
I always wanted to be somebody, but I should have been more specific.
  -- Jane Wagner




