Removing duplicate DWARF2 info

[Jeffrey A Law]

  In message < Pine.LNX.4.21.0007102350050.29170-100000@devserv.devel.redhat.com
>you write:
  > I know this has been hashed over before, but nobody ever seems to do it
  > where it needs to be done (I do it in GDB when we load the stuff), and i'm
  > guessing it's because there are three people on the planet with the
  > knowledge of how LD works that can make this happen.
  > 
  > Why can't we simply not emit the duplicate info, taking LD out of the
  > picture completely.
  > All it seems this would entail is keeping track of what we've emitted info
  > for, over the course of more than one file. 
  > Couldn't we have a simple persistent hash table in a file, and do a lookup
  > in that, then do the check to see if we emitted it during this
  > compilation?
  > That doesn't really seem that tricky to do, or am i missing something?
I don't believe dwarf2 debug records are structured in a way that makes
that kind of scheme easy.

I believe Jason Merrill (jason@cygnus.com) has devised a scheme that allows
these kinds of optimizations to be implemented (in the linker).  But I do not
know its details offhand.


jeff