[Bug other/92396] -ftime-trace support

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92396

--- Comment #5 from Martin Liška <marxin at gcc dot gnu.org> ---
Created attachment 48943
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48943&action=edit
Time trace prototype

So I've just created a prototype patch, but I don't see it much useful:
https://gist.github.com/marxin/dc4354696bc5bd76cdc1d2ecaa4ab060

The main problem is that in case of tree/RTL passes, we run each pass for each
function. Which makes the report full of thin lines.
Thoughts?