[Dwarf-Discuss] constants updates, minor DWARF standard upgrade?

Michael Eager eager at eagercon.com
Fri Jul 20 14:06:57 PDT 2012


On 07/20/2012 12:53 PM, Michael Eager wrote:
> On 07/20/2012 11:46 AM, Cary Coutant wrote:
>> For things like new tags, attributes, language codes, etc., we have
>> occasionally given out assurances that the assigned numbers were safe
>> to use once discussion was complete and the issue was accepted. In
>> most cases, it's then OK to use these without bumping the DWARF
>> version number, since clients are supposed to be able to tolerate
>> unknown values (although binutils is a notable exception). For
>> DW_LANG_Go, we did in fact issue such an assurance.
>
> The DWARF Committee does give any assurances that any proposal will be
> accepted, or that any proposal will be accepted without modification.

Oops.  I read this four times, and it doesn't say what I meant:

The DWARF Committee does NOT give any assurances that any proposal will be
accepted, or that any proposal will be accepted without modification.

> As Ron pointed out, only a released DWARF specification can be
> considered authoritative.  No assurance was given with regard to any
> proposal for adoption in DWARF Version 5, nor has any ever been given
> prior to previous versions of the DWARF standard being released.
>
> As Ian mentioned, when I indicated "Should be OK", that is not an
> assurance that the assignment of a value for DW_LANG_Go would be
> accepted as proposed, only that I thought that it was likely.  As Ian
> said, reliance on this opinion is taken at GCC's risk.
>
> DWARF contains facilities for user extensions and we encourage
> compiler developers to use this methodology.  If developers decide,
> for whatever reason, to not use the extension facilities built
> into DWARF, there is a risk that they will have reverse or modify
> this decision at some future date.  That said, we are cognizant of
> these changes and will try to accommodate them, but we make no
> guarantee or assurances that this will happen.
>
> I hope this clarifies this question.
>
>


-- 
Michael Eager	 eager at eagercon.com
1960 Park Blvd., Palo Alto, CA 94306  650-325-8077





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