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Re: First cut on outputing gimple for LTO using DWARF3. Discussion invited!!!!

mathieu lacage wrote:

I have spent a considerable amount of time looking at the abbrev tables
output by gcc are not totally random: their entries are sorted by their
abbrev code. That is, the abbrev code of entry i+1 is higher than that
of entry i.

That's an interesting observation. Essentially, you've shown that by storing lg(n) information, you can cut the cost to find an entry in an abbreviation table of size n to a constant. Since, for LTO, we certainly can depend on the .o file being produced by GCC, we could depend on this behavior, even though it's not mandated by the DWARF standard.

I think this is probably moot, since I believe that Kenny feels DWARF is not suitable for reasons other than the abbreviation table issue, but this is a clever technique.

Thanks,

--
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713

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