SVR4 Languages SIG

[Dan Oldman]

From: oldman at dg-rtp.dg.com (Dan Oldman)


						   Aug. 27, 1990
Call for Participation: 

UNIX System V Programming Language issues SIG 

Announcing the formation of a UNIX International Special Interest 
Group on Programming Language Issues.  This group will act as a 
clearing house for UI member companies and other interested 
parties to resolve issues of supporting various programming 
languages on UNIX System V.  One pressing problem is the support 
of debugging.

Debugging Support 
================= 

One significant change introduced by System V Release 4 is the 
replacement of COFF (Common Object File Format) with ELF 
(Executable and Linker Format) representation of programs. COFF, 
despite many problems, had a barely acceptable but functional 
representation for debugging information.  ELF, at this time, 
lacks anything but the suggestion that the .debug section might 
contain some debugging information. There is also only a weak 
standard in the area of debugger interface to the kernel. 

The lack of a standard is a serious impediment to third party 
compiler writers who wish to work with the standard system 
debugger and with third party debugger writers that wish to 
operate on many UNIX platforms with standard and third party 
compilers. Any programmer who wishes to debug an application that 
is built with two or more different compilers is also hurt by the 
lack of a standard.
 
Attempting to develop standards in this area is not new. The 
needs of the popular programming languages and debuggers are 
substantial and past attempts have ended with the current 
situation of "agreeing to disagree". This ignores the fact that 
the 80-20 rule applies well here. We can solve the needs of 80% 
of the community with 20% of the work. If we design extensibility 
into the standard, the remaining 20% of the community can build 
on top of the standard and get more done with less effort. 

UNIX Software Labs has developed a new debugger representation, 
called DWARF, that is used in SVR4 C Issue 5 compiler and SDB 
debugger. It has some of the qualities of an acceptable standard 
and would probably be a good place to start. 

Goals of the SIG 
================ 

As stated earlier, the overall goal of the SIG is to provide a 
clearing house for UI member companies and anyone else who has
an interest to resolve programming language support related 
issues on UNIX System V.  There are some specific projects that 
the SIG must complete as soon as possible: 

    1. Develop a robust and efficient framework for debugging 
       information. This framework will consist of a generic base 
       that deals with the common problems of the popular third 
       generation languages and supports extensibility for other 
       uses. 
    
    2. Define how the following languages map onto this 
       framework: C (K&R and ANSI), Fortran (77 and 90), C++, and 
       probably others.
    
    3. Define the format of "core" files.
    
    4. Define the interface between the debugger and the RTLD 
       (shared library runtime loader).
    
    5. Define a standard for Kernel support of debugging and then 
       extend that standard to deal with upcoming features like 
       threads. 

Beyond that there are other issues that could be standardized 
such as support for debugging in the absence of debugger 
information and support for long long integer types.  I'm sure 
that there are more things that I have not mentioned here.

Mechanism 
========= 

It is the intention of the SIG to have bi-monthly meetings and 
heavy network and conference call communication. We plan to have 
an organizational meeting in late September.  Here's a start for 
the proposed agenda. I will add anything else to it that is 
requested. (See feedback below.) 

    Introductions and opportunity for individuals to state their 
	interest and what they expect the SIG to accomplish
    
    Charter discussions and election of officers 
    
    Standardization priorities
    
    Debugger issues 
    
       Overall Goals of Debugging Information 
       
       Proposal for the framework 
    
    Discussion about the next meeting 

Feedback 
======== 

For the first meeting, I am targeting Thursday September 27th in the
Boston area, but a final decision won't be made until I hear from
the people who are interested in being involved.  Please respond 
before Friday, September 7th, via email, fax, mail, or phone with the 
information requested below.  I will acknowledge any messages that you 
send me to avoid things being lost in the mail.

    Name: 
    Organization: 
    Area of interest: 
    Phone number: 
    Fax number: 
    Email address: 
    Mail address: 
    Level of interest: 
       __ I will attend most meetings and am willing to do 
          significant spec writing. 
       __ I will attend most meetings and actively review       
          proposals. 
       __ I will actively monitor the email discussions, but will 
          not be able to attend meetings. 
       __ I am interested in occasional status reports. 
    Preferred location for meetings: 
   
    __ I can make it to the first meeting if it adheres to the 
       following time or location constraints: 
    
    I would like the following added to the agenda: 
    
    Any other comments:


Thank you for your interest. 
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Dan Oldman                        internet: oldman at dg-rtp.dg.com
Data General Corporation          uucp: ...!mcnc!rti!dg-rtp!oldman
62 Alexander Drive                voice: (919) 248-6125 
Research Triangle Park, NC 27709  fax:   (919) 541-9089 
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Volume-Number: Volume 21, Number 80