Re: [PATCH] Fix dwarf register column to gdb register mapping

["Randolph Chung" <randolph at tausq dot org>]

When I enabled the dwarf debugging support in gdb before i caused
various errors and warnings about incorrect cfi. Do you still see that
with this enabled? Is it compiler dependent? Because of those warnings
and errors I had disabled the dwarf stuff on hppa before.

Looks good to me otherwise. Thanks for fixing it.

randolph

On Sat, Sep 13, 2008 at 4:32 PM, John David Anglin
<dave@hiauly1.hia.nrc.ca> wrote:
> The following revises hppa_dwarf_reg_to_regnum and hppa64_dwarf_reg_to_regnum
> to implement my understanding of the mapping needed on hppa.  The dwarf
> columns essentially correspond one-to-one to the GCC internal register
> numbering.  I think someone must have been looking at the dbx numbering
> when these routines were first implemented.  The numbering used by gdb
> for hppa is in hppa-tdep.h.
>
> The sniffer stuff is obsolete.
>
> Tested on hppa64-hp-hpux11.11 and hppa-unknown-linux-gnu.
>
> Ok?
>
> Dave
> --
> J. David Anglin                                  dave.anglin@nrc-cnrc.gc.ca
> National Research Council of Canada              (613) 990-0752 (FAX: 952-6602)
>
> 2008-09-13  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
>
>        * hppa-linux-tdep.c (hppa_dwarf_reg_to_regnum): Remove "#if 0" "#endif".
>        Fix mapping of dwarf columns to gdb registers.
>        (hppa_linux_init_abi): Call set_gdbarch_dwarf2_reg_to_regnum.  Delete
>        disabled code.
>        * hppa-tdep.c (hppa64_dwarf_reg_to_regnum): Fix mapping of dwarf columns
>        to gdb registers.
>
> Index: hppa-linux-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/hppa-linux-tdep.c,v
> retrieving revision 1.31
> diff -u -3 -p -r1.31 hppa-linux-tdep.c
> --- hppa-linux-tdep.c   21 Aug 2008 13:19:18 -0000      1.31
> +++ hppa-linux-tdep.c   13 Sep 2008 22:51:35 -0000
> @@ -34,24 +34,26 @@
>
>  #include "elf/common.h"
>
> -#if 0
>  /* Convert DWARF register number REG to the appropriate register
>    number used by GDB.  */
>  static int
> -hppa_dwarf_reg_to_regnum (int reg)
> +hppa_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
>  {
> -  /* registers 0 - 31 are the same in both sets */
> -  if (reg < 32)
> +  /* r1-r31 are the same in both sets (column for r0 is not used)  */
> +  if (reg >= 1 && reg < 32)
>     return reg;
>
> -  /* dwarf regs 32 to 85 are fpregs 4 - 31 */
> -  if (reg >= 32 && reg <= 85)
> +  /* Dwarf registers 32 to 87 are the floating point registers fr4 to fr31.  */
> +  if (reg >= 32 && reg < 88)
>     return HPPA_FP4_REGNUM + (reg - 32);
>
> +  /* Dwarf register 88 is the sar register.  */
> +  if (reg == 88)
> +    return HPPA_SAR_REGNUM;
> +
>   warning (_("Unmapped DWARF Register #%d encountered."), reg);
>   return -1;
>  }
> -#endif
>
>  static void
>  hppa_linux_target_write_pc (struct regcache *regcache, CORE_ADDR v)
> @@ -545,12 +548,7 @@ hppa_linux_init_abi (struct gdbarch_info
>   set_gdbarch_regset_from_core_section
>     (gdbarch, hppa_linux_regset_from_core_section);
>
> -#if 0
> -  /* Dwarf-2 unwinding support.  Not yet working.  */
>   set_gdbarch_dwarf2_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum);
> -  frame_unwind_append_sniffer (gdbarch, dwarf2_frame_sniffer);
> -  frame_base_append_sniffer (gdbarch, dwarf2_frame_base_sniffer);
> -#endif
>
>   /* Enable TLS support.  */
>   set_gdbarch_fetch_tls_load_module_address (gdbarch,
> Index: hppa-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/hppa-tdep.c,v
> retrieving revision 1.260
> diff -u -3 -p -r1.260 hppa-tdep.c
> --- hppa-tdep.c 11 Sep 2008 14:23:15 -0000      1.260
> +++ hppa-tdep.c 13 Sep 2008 22:51:35 -0000
> @@ -661,13 +661,17 @@ hppa64_register_name (struct gdbarch *gd
>  static int
>  hppa64_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
>  {
> -  /* r0-r31 and sar map one-to-one.  */
> -  if (reg <= 32)
> +  /* r1-r31 are the same in both sets (column for r0 is not used).  */
> +  if (reg >= 1 && reg < 32)
>     return reg;
>
> -  /* fr4-fr31 are mapped from 72 in steps of 2.  */
> -  if (reg >= 72 || reg < 72 + 28 * 2)
> -    return HPPA64_FP4_REGNUM + (reg - 72) / 2;
> +  /* fr4-fr31 are mapped to 72, 74, 76 ...  */
> +  if (reg >= 32 && reg < 60)
> +    return HPPA64_FP4_REGNUM + 2 * (reg - 32);
> +
> +  /* Dwarf register 60 is the sar register.  */
> +  if (reg == 60)
> +    return HPPA_SAR_REGNUM;
>
>   error ("Invalid DWARF register num %d.", reg);
>   return -1;
>