[LLVMdev] DWARF 2/3 backwards compatibility?

[Eric Christopher]

> Would like to discuss:
> 1) What level of interest is there in Dwarf backward compatibility;

I don't have a lot of interest in keeping dwarf backward compatibility
past my ability to test things, hence the option for darwin's gdb.
That said if people want to have more strict options I can easily keep
the dwarf stuff I'm working on inside of that framework.

> 2) What levels of Debugger backward compatibility are needed.

Probably "old gdb" which for a lot of our platforms is pretty much the
darwin gdb. If we absolutely need to we can wall things off based on
dwarf version, but that's a bit of a pain. At that point I'd probably
want to throw something into either that compile unit metadata or the
module itself on what level of dwarf I can use. Bill's work on module
level attributes would probably come in a little handy here.

> 3) What framework of flags/options would be a container for specific
> backward compatibility features.

DWARF version is probably the easiest for now. If we ever hit the
point of emitting another form of debug info we can worry about that.

> 4) What type of testing to ensure backward compatibility, GDB Testsuite?

This is key, if there's no way I can test that I haven't broken a
platform (or at the least something yelling at me that I have broken a
platform) then there's not much I can do about it.

-eric