Type representation in CTF and DWARF

[Pedro Alves]

On 10/4/19 8:23 PM, Indu Bhagat wrote:
> Hello,
> 
> At GNU Tools Cauldron this year, some folks were curious to know more on how
> the "type representation" in CTF compares vis-a-vis DWARF.

I was one of those, and I brought this up to Jose, after your
presentation.  Glad to see the follow up!  Thanks much for this.

In your Cauldron presentation we saw CTF compared to full blown DWARF
as justification for CTF, but I was more interested in a comparison between
CTF and a DWARF subset containing exactly only what you have available in
CTF.  Because if DWARF with everything-you-don't-need stripped out
is in the same ballpark, then I am puzzled on why add/maintain a new
Debug format, with all the duplication of effort that entails going
forward.

Also, it's my understanding that the current CTF format doesn't yet
support C++, Vector registers, etc., maybe other things, so if DWARF
was sufficient for your needs, then in the long run it sounds like
a better option to me, as then you wouldn't have to extend CTF _and_
DWARF whenever some feature is needed.

Maybe it would make sense to work on integrating CTF into the DWARF
standard itself, not sure?

I was also curious on your plans for adding unwinding support to CTF,
while the kernel (the main CTF user, IIUC), already has plans to 
use its own unwinding format (ORC)?

So with all those questions, I came out of the presentation
thinking that I could not really justify CTF if I were asked to.

(Side note: the Cauldron page is missing slides for your
presentation, so I couldn't go and recheck some things
mentioned above.)

Thanks,
Pedro Alves