Re: [PATCH] S/390 DWARF-2 CFI frame support

[Mark Kettenis <kettenis@chello.nl>]

   Date: Sun, 14 Dec 2003 11:40:50 -0500
   From: Andrew Cagney <cagney@gnu.org>

   > The reason why I added that hack in the first place is the case where
   > the return address column does not correspond to an actual register.
   > In that case we must make sure that we don't map it onto one of GDB's
   > (pseudo-)registers.  Assuming that the compiler has some freedom in
   > choosing the return address column number, and considering that the
   > DWARF-2 register numbers are largely undocumented for most targets, I
   > was worried that I couldn't guarantee this.
   > 
   > AFAICT there is no platform yet where GCC uses a return address column
   > number that would be mapped on the wrong GDB register, so I think we
   > can safely remove the code.  New targets that start using the DWARF-2
   > CFI stuff should make sure theur DWARF-2 register number mapping is
   > right.

   Well, ... the PPC64 return-column, when I last looked, specified the 
   dwarf2' floating-point status and control register number!  But let the 
   person framifying the PPC64 sort that one out :-)

Argh!  Someone teach GCC about the PPC64 DWARF register numbering
please!  Before it is too late!  Now it is using the PPC32 LR register
number, which just happens to be the PPC64 FPSCR register.

   Anyway, with respect to your proposal, yes like it.

I'll see whether I can implement it.

Mark