🚀 go-pugleaf

| From: pcg@aber-cs.UUCP (Piercarlo Grandi)
| Newsgroups: gnu.gdb.bug
| Summary: You could put extra COFF debug information in a section...
| Date: 22 Feb 90 14:53:33 GMT
| Reply-To: pcg@cs.aber.ac.uk (Piercarlo Grandi)
| Distribution: gnu
| Organization: Dept of CS, UCW Aberystwyth
| 	(Disclaimer: my statements are purely personal)
| 
| In article <MEISSNER.90Feb19125329@curley.osf.org> meissner@osf.org (Michael Meissner) writes:
|   
|   When I worked at Data General, I maintained that the "C" in COFF meant
|   crippled, and not common, mostly because of the limitations of the
|   debug format.
| 
| We have already discussed some of this in the G++ groups, because the problem
| is much worse for it. I think that, waiting for ELF, COFF can still be
| used if oen is prepared to do a hack similar to that used for the AOUT
| format. In AOUT the debugging information is emitted as simple strings, and
| the native AOUT debug format is practically bypassed.

(Un)forturnately, ELF does not define a standard debug format.  The
people at Data General who looked into it, could not find anything in
the specs about it (they finally had to resort to reading the code for
the SDB rewrite in C++).  Evidently, it was felt that the debug format
was a private choice that the compiler and debugger made.  88Open and
possibly other vendors looking at going to System V.4 also made the
same choice.

As much as I detest the COFF debug format, I believe that a
standardized debug format is useful, in that it allows you to intermix
compiler A with debugger B.

| In COFF you could easily (very easily) use a section to hold debug
| tables in whatever format. This section could be something like the .comment
| section that is already customary with COFF executables (and that often
| munches up a lot of space in them -- use 'mcs -d' as well as 'strip' ...).
| I actually feel that using the .comment section would be fine.

On System V systems, .comment is not a good idea, since #ident strings
go in there, and a debugger might find it hard to distinguish where
the ident strings end for a module, and other modules debug info.

Note that on a Decstation, which uses the MIPS 1.31 compiler tools,
the assembler gives you no way using other sections except for the
default .text/.data/.sdata/.rdata/.sbss/.bss sections.  I have toyed
with doing this for GCC on the Decstation.