[07/25] gdb/mips: Use default gdbarch methods where possible

  Make use of the default gdbarch methods for gdbarch_dummy_id, and
gdbarch_unwind_sp where possible.

I have not tested this change but, by inspecting the code, I believe
the default methods are equivalent to the code being deleted.

One thing worth noting in this commit is that the accesses to the
stack pointer register changes from being signed to unsigned, however,
in all cases the register is immediately converted to a CORE_ADDR, so
I don't think this will cause any problems.

gdb/ChangeLog:

	* mips-tdep.c (mips_unwind_sp): Delete.
	(mips_dummy_id): Delete.
	(mips_gdbarch_init): Don't register deleted functions with
	gdbarch.
---
 gdb/ChangeLog   |  7 +++++++
 gdb/mips-tdep.c | 24 ------------------------
 2 files changed, 7 insertions(+), 24 deletions(-)
  

On Wed, 27 Mar 2019 21:34:03 +0000
Andrew Burgess <andrew.burgess@embecosm.com> wrote:

> -static CORE_ADDR
> -mips_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
> -{
> -  return frame_unwind_register_signed
> -	   (next_frame, gdbarch_num_regs (gdbarch) + MIPS_SP_REGNUM);
> -}

I don't think this one is equivalent to the default method since it's
using frame_unwind_register_signed (instead of _unsigned).

> -/* Assuming THIS_FRAME is a dummy, return the frame ID of that
> -   dummy frame.  The frame ID's base needs to match the TOS value
> -   saved by save_dummy_frame_tos(), and the PC match the dummy frame's
> -   breakpoint.  */
> -
> -static struct frame_id
> -mips_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
> -{
> -  return frame_id_build
> -	   (get_frame_register_signed (this_frame,
> -				       gdbarch_num_regs (gdbarch)
> -				       + MIPS_SP_REGNUM),
> -	    get_frame_pc (this_frame));
> -}
> -

I'm not confident that this one is equivalent either due to calling
get_frame_register_signed.  However, I don't really know because I
haven't traced the calls to see whether a signed or unsigned version
ultimately gets called.

Kevin
  

* Kevin Buettner <kevinb@redhat.com> [2019-03-27 15:31:40 -0700]:

> On Wed, 27 Mar 2019 21:34:03 +0000
> Andrew Burgess <andrew.burgess@embecosm.com> wrote:
> 
> > -static CORE_ADDR
> > -mips_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
> > -{
> > -  return frame_unwind_register_signed
> > -	   (next_frame, gdbarch_num_regs (gdbarch) + MIPS_SP_REGNUM);
> > -}
> 
> I don't think this one is equivalent to the default method since it's
> using frame_unwind_register_signed (instead of _unsigned).
> 
> > -/* Assuming THIS_FRAME is a dummy, return the frame ID of that
> > -   dummy frame.  The frame ID's base needs to match the TOS value
> > -   saved by save_dummy_frame_tos(), and the PC match the dummy frame's
> > -   breakpoint.  */
> > -
> > -static struct frame_id
> > -mips_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
> > -{
> > -  return frame_id_build
> > -	   (get_frame_register_signed (this_frame,
> > -				       gdbarch_num_regs (gdbarch)
> > -				       + MIPS_SP_REGNUM),
> > -	    get_frame_pc (this_frame));
> > -}
> > -
> 
> I'm not confident that this one is equivalent either due to calling
> get_frame_register_signed.  However, I don't really know because I
> haven't traced the calls to see whether a signed or unsigned version
> ultimately gets called.

I agree with your concerns.  I think this patch only should be dropped
from this series.

Thanks,
Andrew