Re: [PATCH] Remove md_reg_eh_frame_to_debug_frame on PPC (Re: [RFC] Wrong register numbers in .dwarf_frame on Linux/PowerPC)

["Ulrich Weigand" <uweigand at de dot ibm dot com>]

Alan Modra wrote:
> On Thu, Dec 11, 2014 at 09:27:30PM +0100, Ulrich Weigand wrote:
> > GCC has now been changed to implement suggestion 3 here:
> > https://gcc.gnu.org/ml/gcc-patches/2014-10/msg00685.html
> > 
> > So I think we should also change GAS to match the new GCC behavior.
> > This simply means removing the PPC-specific definition of the macro
> > md_reg_eh_frame_to_debug_frame.
> > 
> > The attached patch implements this.
> 
> If I understand the gcc code correctly, it seems to me that the patch
> doesn't make gas match the new gcc behaviour.  :-(
> 
> To be consistent with gcc, shouldn't this instead be something like
> the following?  (It also needs another emulation file defining TE_AIX
> to support aix < 5.)

Ah, you're right -- I hadn't considered non-Linux platforms (but then,
they weren't supported previously either ...).   Not sure if all of these
platforms actually use gas to create .debug_frame sections, but it would
certainly be better to be compatible to gcc if they do.

> diff --git a/gas/config/tc-ppc.h b/gas/config/tc-ppc.h
> index 3cd9bf1..8c80e8a 100644
> --- a/gas/config/tc-ppc.h
> +++ b/gas/config/tc-ppc.h
> @@ -267,11 +267,24 @@ extern int ppc_parse_name (const char *, struct expressionS *);
>  #define md_cleanup() ppc_cleanup ()
>  extern void ppc_cleanup (void);
>  
> +#if (defined TE_AIX5 || defined TE_AIX					\
> +     || defined TE_FreeBSD || defined TE_NetBSD || defined TE_LYNX)
>  /* ppc uses different register numbers between .eh_frame and .debug_frame.
>     This macro translates the .eh_frame register numbers to .debug_frame
>     register numbers.  */
> -#define md_reg_eh_frame_to_debug_frame(regno) \
> -  ((regno) == 70 ? 64 /* cr2 */ : (regno))
> +#define md_reg_eh_frame_to_debug_frame(regno)				\
> +  ((regno) == 70 ? 64	/* cr2 */					\
> +   : (regno) == 65 ? 108 /* lr */					\
> +   : (regno) == 66 ? 109 /* ctr */					\
> +   : (regno) >= 68 && (regno) <= 75 ? (regno) + 86 - 68 /* crN */	\
> +   : (regno) == 76 ? 101 /* xer */					\
> +   : (regno) >= 77 && (regno) <= 108 ? (regno) + 1124 - 77 /* vrN */	\
> +   : (regno) == 109 ? 356 /* vrsave */					\
> +   : (regno) == 110 ? 67 /* vscr */					\
> +   : (regno) == 111 ? 99 /* spe_acc */					\
> +   : (regno) == 112 ? 612 /* spefscr */					\
> +   : (regno))
> +#endif

This looks good to me.

Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  GNU/Linux compilers and toolchain
  Ulrich.Weigand@de.ibm.com