Re: [PATCH 1/3] Add sp_regnum_from_eax and pc_regnum_from_eax

Mark Kettenis
2012-07-03T14:08:31Z

> Date: Thu, 21 Jun 2012 11:14:52 -0700
> From: "H.J. Lu" <hongjiu.lu@intel.com>
>
> Hi,
>
> Here are the first of the last 3 patches for x32 support in GDB. This
> patch maps $pc to $eip and $sp to $esp for x32. OK to install?

The pseudo register handling code is getting too complex :(. I feel
that hiding the set_gdbarch_pc_regnum() and set_gdbarch_sp_regnum()
calls in i386-tdep.c isn't the right approach. But I haven't found a
better one yet :(.

> ---
> * amd64-tdep.c (amd64_x32_init_abi): Set sp_regnum_from_eax to
> AMD64_RSP_REGNUM and pc_regnum_from_eax to AMD64_RIP_REGNUM.
>
> * i386-tdep.c (i386_gdbarch_init): Initialize sp_regnum_from_eax
> and pc_regnum_from_eax to -1. Update SP regnum from
> sp_regnum_from_eax and PC regnum from pc_regnum_from_eax if
> needed.
>
> * i386-tdep.h (gdbarch_tdep): Add sp_regnum_from_eax and
> pc_regnum_from_eax.
>
> ---
> gdb/amd64-tdep.c | 3 +++
> gdb/i386-tdep.c | 11 +++++++++++
> gdb/i386-tdep.h | 8 ++++++++
> 3 files changed, 22 insertions(+), 0 deletions(-)
>
> diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
> index 8ae1142..5424926 100644
> --- a/gdb/amd64-tdep.c
> +++ b/gdb/amd64-tdep.c
> @@ -2946,6 +2946,9 @@ amd64_x32_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
> tdesc = tdesc_x32;
> tdep->tdesc = tdesc;
>
> + tdep->sp_regnum_from_eax = AMD64_RSP_REGNUM;
> + tdep->pc_regnum_from_eax = AMD64_RIP_REGNUM;
> +
> tdep->num_dword_regs = 17;
> set_tdesc_pseudo_register_type (gdbarch, amd64_x32_pseudo_register_type);
>
> diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
> index fd5969d..6a02906 100644
> --- a/gdb/i386-tdep.c
> +++ b/gdb/i386-tdep.c
> @@ -7805,6 +7805,9 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
> tdep->num_mmx_regs = 8;
> tdep->num_ymm_regs = 0;
>
> + tdep->sp_regnum_from_eax = -1;
> + tdep->pc_regnum_from_eax = -1;
> +
> tdesc_data = tdesc_data_alloc ();
>
> set_gdbarch_relocate_instruction (gdbarch, i386_relocate_instruction);
> @@ -7849,6 +7852,14 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
> /* Support dword pseudo-register if it hasn't been disabled. */
> tdep->eax_regnum = ymm0_regnum;
> ymm0_regnum += tdep->num_dword_regs;
> + if (tdep->sp_regnum_from_eax != -1)
> + set_gdbarch_sp_regnum (gdbarch,
> + (tdep->eax_regnum
> + + tdep->sp_regnum_from_eax));
> + if (tdep->pc_regnum_from_eax != -1)
> + set_gdbarch_pc_regnum (gdbarch,
> + (tdep->eax_regnum
> + + tdep->pc_regnum_from_eax));
> }
> else
> tdep->eax_regnum = -1;
> diff --git a/gdb/i386-tdep.h b/gdb/i386-tdep.h
> index 5f233f5..76afdce 100644
> --- a/gdb/i386-tdep.h
> +++ b/gdb/i386-tdep.h
> @@ -149,6 +149,14 @@ struct gdbarch_tdep
> of pseudo dword register support. */
> int eax_regnum;
>
> + /* Register number for SP, relative to %eax. Set this to -1 to
> + indicate the absence of pseudo SP register support. */
> + int sp_regnum_from_eax;
> +
> + /* Register number for PC, relative to %eax. Set this to -1 to
> + indicate the absence of pseudo PC register support. */
> + int pc_regnum_from_eax;
> +
> /* Number of core registers. */
> int num_core_regs;
>
> --
> 1.7.6.5
>
>