Incorrect DWARF-2 register numbers on PPC64?

[Ulrich Weigand]

Hello,

FYI: this came up on the GDB mailing list -- could you have a look?

Mit freundlichen Gruessen / Best Regards

Ulrich Weigand

--
  Dr. Ulrich Weigand
  Linux for S/390 Design & Development
  IBM Deutschland Entwicklung GmbH, Schoenaicher Str. 220, 71032 Boeblingen
  Phone: +49-7031/16-3727   ---   Email: Ulrich.Weigand@de.ibm.com
---------------------- Forwarded by Ulrich Weigand/Germany/IBM on
18.12.2003 18:20 ---------------------------

Mark Kettenis <kettenis@chello.nl> on 14.12.2003 18:14:52

To:    cagney@gnu.org
cc:    weigand@i1.informatik.uni-erlangen.de,
       gdb-patches@sources.redhat.com, Ulrich Weigand/Germany/IBM@IBMDE
Subject:    Re: [PATCH] S/390 DWARF-2 CFI frame support


   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