once we have cpplib...

[Jeffrey A Law]

  In message < r24t04i3n9.fsf@happy.cygnus.com >you write:
  > there is lately some motion to get cpplib finally used in gcc.  Once
  > this is done we have several more options and I think we should plan
  > on them now.
Yup.  In fact, I just checked in the first group of changes from Dave
to move us in that direction.

  > - with cpplib it'll be possible for the compiler to get the hands on the
  >   the macro definitions.  This will
  > 
  >   * allow to emit debug info about macros which can be disaplyed in gdb
  >     when DWARF is used
  > 
  >   * finally allow to use the debugger on code in macros since the line
  >     number information is available
Yup.  Big win, especially for those of us how debug gcc where big
macros are far too common :( 


  > - cpplib must be in sync with the current cccp.  I think Paul did it most
  >   of the time but is everything included?
Probably not.  Someone will have to go through each change to cccp
to make sure it's in cpplib.  Not pleasant, but necessary.

  > - we need a way to allow old gcc drivers call new backends and vice versa.
  >   Probably this can be achieved by adding some more specs file entries.
Well, I find -V a nice thing to have, but I don't mind breaking it
for something this significant.  Or just make cpp a trivial program
that calls gcc with the right arguments to put it into "cpp" mode :-)

  > Comment on this?  Any points I forgot?
We'll still want "-save-temps" to dump out the .i file of preprocessed
output.  Probably other minor nits that we've both forgotten.

jeff