PATCH: PR backtrace/14646: [x32] backtrace doesn't work

["H.J. Lu" <hjl dot tools at gmail dot com>]

Hi,

amd64_x32_init_abi has

  tdep->sp_regnum_from_eax = AMD64_RSP_REGNUM;
  tdep->pc_regnum_from_eax = AMD64_RIP_REGNUM;

But unwind frame info is based on the real RSP/RIP
registers.  Pseudo sp/pc registers don't work with
frame related codes:

[hjl@gnu-tools-1 gdb]$ egrep "pc_regnum|sp_regnum" *fram*.c 
dwarf2-frame.c:  if (regnum == gdbarch_pc_regnum (gdbarch))
dwarf2-frame.c:  else if (regnum == gdbarch_sp_regnum (gdbarch))
dwarf2-frame.c:          == gdbarch_sp_regnum (gdbarch)))
dwarf2-frame-tailcall.c:  if (regnum == gdbarch_pc_regnum
(this_gdbarch))
dwarf2-frame-tailcall.c:  else if (cache->prev_sp_p && regnum ==
gdbarch_sp_regnum (this_gdbarch))
dwarf2-frame-tailcall.c:      int sp_regnum;
dwarf2-frame-tailcall.c:      sp_regnum = gdbarch_sp_regnum
(prev_gdbarch);
dwarf2-frame-tailcall.c:      if (sp_regnum == -1)
dwarf2-frame-tailcall.c:      prev_sp = frame_unwind_register_unsigned
(this_frame, sp_regnum);
frame.c:      && gdbarch_pc_regnum (gdbarch) >= 0
frame.c:                      gdbarch_pc_regnum (gdbarch),
frame.c:                      gdbarch_pc_regnum (gdbarch),
frame.c:     the gdbarch_sp_regnum register is meaningful.  */
frame.c:  if (gdbarch_sp_regnum (gdbarch) >= 0)
frame.c:                    gdbarch_sp_regnum (gdbarch));
[hjl@gnu-tools-1 gdb]$ 

It is nice to print

(gdb) p $sp
$1 = (void *) 0xffffd028

instead of

(gdb) p $sp
$1 = 4294955048

But it breaks frame unwind.  This patch removes pseudo sp/pc regnum from
x32.  "p $sp" and "p $pc" will print 64bit integers.  But "p $esp" and
"p $esp" work fine.  OK for trunk and 4.5 branch?

Thanks.
  

H.J.
---
2012-09-30  H.J. Lu  <hongjiu.lu@intel.com>

	PR backtrace/14646
	PR gdb/14647
	* i386-tdep.h (gdbarch_tdep): Remove sp_regnum_from_eax and
	pc_regnum_from_eax.
	* i386-tdep.c (i386_gdbarch_init): Don't use sp_regnum_from_eax
	nor pc_regnum_from_eax.
	* amd64-tdep.c (amd64_x32_init_abi): Don't set sp_regnum_from_eax
	nor pc_regnum_from_eax.

diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
index 5424926..8ae1142 100644
--- a/gdb/amd64-tdep.c
+++ b/gdb/amd64-tdep.c
@@ -2946,9 +2946,6 @@ 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 84e9794..ddb20aa 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -7705,9 +7705,6 @@ 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);
@@ -7752,14 +7749,6 @@ 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 76afdce..5f233f5 100644
--- a/gdb/i386-tdep.h
+++ b/gdb/i386-tdep.h
@@ -149,14 +149,6 @@ 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;