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Re: Incorrect DWARF-2 register numbers on PPC64?
- From: Andrew Cagney <cagney at gnu dot org>
- To: Alan Modra <amodra at bigpond dot net dot au>
- Cc: Mark Kettenis <kettenis at chello dot nl>, gcc-patches at gcc dot gnu dot org,geoffk at desire dot geoffk dot org, dje at watson dot ibm dot com,gdb-patches at sources dot redhat dot com, Ulrich dot Weigand at de dot ibm dot com
- Date: Wed, 07 Jan 2004 18:35:59 -0500
- Subject: Re: Incorrect DWARF-2 register numbers on PPC64?
- References: <OFEA5CA921.302AEEB5-ON41256E00.005FB141@de.ibm.com> <200312182258.hBIMwgT25422@makai.watson.ibm.com> <200312201527.hBKFRHgI000712@elgar.kettenis.dyndns.org> <3FF5A069.firstname.lastname@example.org> <200401022317.i02NHQBR001191@desire.geoffk.org> <20040106152710.GB2533@bubble.modra.org> <200401071743.i07HhAle000811@elgar.kettenis.dyndns.org> <20040107222907.GO2533@bubble.modra.org>
On Wed, Jan 07, 2004 at 06:43:10PM +0100, Mark Kettenis wrote:
If I read your patch correctly, this fixes normal DWARF 2 debugging
info to use the official System V register numbers, but lets GCC
continue to use its own numbering for the Call Frame Info (CFI) in
both the .eh_frame and .debug_frame sections.
That's correct. hppa, hppa64, iq2000 and ns32k all do the same.
mips and cris also define DWARF_FRAME_REGNUM, but squinting at the code
leads me to believe they will actually use the same register numbers.
(same as which? gcc or dwarf 2?)
This won't work for GDB
since it assumes that CFI uses the same register number encoding as
all the other DWARF 2 debug information.
Hmm, I can see that a debugger might reasonably expect .debug_frame
to have the same numbers. When I wrote the patch, I was concentrating
on .eh_frame rather than .debug_frame, but .debug_frame uses the
.eh_frame numbering. It's a little perplexing that dwarf2out.c does
this, as it means defining DWARF_FRAME_REGNUM to something other
than DBX_REGISTER_NUMBER is useless. DWARF_FRAME_REGNUM ought to
just effect .eh_frame. I'm not keen on trying to untangle dwarf2out.c
Is it going to be possible to get this untangled before 3.4 is