rfg@ncd.com (Ron Guilmette - C++ Entomologist) (08/22/90)
I've noticed over time that the messages in this newsgroup tend to focus mostly on the more intellectually interesting aspects of compiler construction (e.g. the recent discussion of intermediate representations and their relationship to optimization techniques). If I may, I'd like to see if any of the readership (other than me) would perhaps have an interest in discussing (what may be viewed as) one of the more mundane practical considerations of compiler construction in this day and age. In particular, I'd like to solicit people's views regarding the new format for symbolic debugging information which is now being promulgated by AT&T as a part of System V Release 4. For those who don't already know, back in the the good ol' days, the COFF `standard' (and I use the term loosely) specified the general format for object files (i.e. headers, relacation information, etc.) and also specified the format for symbolic debugging information. As most COFF users already know, COFF left a bit to be desired in terms of the symbolic debugging information. Therefore, I (and others) actually welcomed the introduct (by AT&T) of yet another object file format (i.e. ELF). I (and others) had high hopes that ELF would be dramatically better than COFF, especially with regard to the provisions for symbolic debugging information within the new format. Well, unfortunately, all is not well here in the new age. First, for reasons which are not entirely clear (but which may relate to the internal opinions and external clout of one particular hardware manufacturer) the ELF object file format does *not* include any specification of symbolic debugging information. Rather, this information has been segregated out and is covered (separately) under the name of DWARF. The AT&T folks are not really going out of their way to promote DWARF. Rather, their attitude seems to be more like "Here it is. Use it if you want to. If you don't like it, that's OK too. We don't demand that anybody use it." Now this seems to be very broad-minded attitude on the part of AT&T (and perhaps it is), but it seems that most folks who are implementing V.4 or stuff related to V.4, or who are otherwise interested in ELF are too small to try to swim against the tide and implement something other than the de facto standard (i.e. ELF+DWARF). So the net result seems to be that most companies who are doing ELF are also doing DWARF. Now ELF+DWARF, while being an improvement over COFF, still leave some things to be desired. I'd like to know if other people, companies, or organizations have noticed any of the problems in ELF+DWARF that I have seen, and if so what (if anything) they plan to do about them. I'm posting this message in comp.compilers because I believe that this is probably the best place to make contact with the kind of folks that would have an interest in this subject (i.e. compiler & debugger people). Please E-mail responses to me unless you think that you have something of general interest to say on this subject. // Ron Guilmette - C++ Entomologist // Internet: rfg@ncd.com uucp: ...uunet!lupine!rfg [I'd be interested to hear what DWARF's problems are, other than its name. -John] -- Send compilers articles to compilers@esegue.segue.boston.ma.us {ima | spdcc | world}!esegue. Meta-mail to compilers-request@esegue.