What COFF (windows .obj object file) viewers are available?
There is DbgHelp, but it's geared more toward the PE file rather than the object file. And Its intended to be used as an API rather than a tool.
the COFF format itself originated on unix http://en.wikipedia.org/wiki/COFF although Microsoft has extended the format somewhat and the unix seems to have abandoned that format in favor of ELF. But you might find some useful tools in the Unix world, for instance this dump tool from SCO http://docsrv.sco.com:507/en/man/html.CP/dump.CP.html
Just convert the COFF format to ELF and use some ELF viewer:
objcopy.exe --input-target=pe-i386 --output-target=elf32-i386 somefile.o somefile.elfFor example in Python you can then use this one-file-implementation, which only depends on the struct module: http://www.tinyos.net/tinyos-2.1.0/tools/platforms/msp430/pybsl/elf.py