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

H.J. Lu
2012-07-03T23:56:18Z

On Tue, Jul 3, 2012 at 12:14 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Tue, Jul 3, 2012 at 10:35 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Tue, Jul 3, 2012 at 8:54 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Tue, Jul 3, 2012 at 7:08 AM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
>>>>> 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 :(.
>>>>
>>>
>>> One possibility is to set pc/sp to register name instead of regnum.
>>> i386_gdbarch_init can map them to regnum after all pseudo registers
>>> are finalized.
>>>
>>> --
>>> H.J.
>>
>> How about this patch? I can also change amd64 and i386
>> to use "rsp/"rsp"/"esp"/"eip".
>>
>
> This patch sets SP?PC regnums from register names.
>
>

Here is another approach to set SP/PC regnums after
setting up pseudo registers.

--
H.J.
---
* amd64-tdep.c (amd64_init_abi): Set sp_regnum to AMD64_RSP_REGNUM
and set pc_regnum to AMD64_RIP_REGNUM. Don't call
set_gdbarch_sp_regnum nor set_gdbarch_pc_regnum here.
(amd64_x32_init_abi): Set sp_regnum to -AMD64_RSP_REGNUM and set
pc_regnum to -AMD64_RIP_REGNUM.

* i386-tdep.c (i386_gdbarch_init): Set sp_regnum to I386_ESP_REGNUM
and set pc_regnum to I386_EIP_REGNUM. Call set_gdbarch_sp_regnum
and set_gdbarch_pc_regnum after setting up pseudo registers.

* i386-tdep.h (gdbarch_tdep): Add sp_regnum and pc_regnum.

diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
index 8ae1142..df0df08 100644
--- a/gdb/amd64-tdep.c
+++ b/gdb/amd64-tdep.c
@@ -2846,8 +2846,8 @@ amd64_init_abi (struct gdbarch_info info, struct
gdbarch *gdbarch)
set_gdbarch_num_regs (gdbarch, AMD64_NUM_REGS);

/* Register numbers of various important registers. */
- set_gdbarch_sp_regnum (gdbarch, AMD64_RSP_REGNUM); /* %rsp */
- set_gdbarch_pc_regnum (gdbarch, AMD64_RIP_REGNUM); /* %rip */
+ tdep->sp_regnum = AMD64_RSP_REGNUM; /* %rsp */
+ tdep->pc_regnum = AMD64_RIP_REGNUM; /* %rip */
set_gdbarch_ps_regnum (gdbarch, AMD64_EFLAGS_REGNUM); /* %eflags */
set_gdbarch_fp0_regnum (gdbarch, AMD64_ST0_REGNUM); /* %st(0) */

@@ -2946,6 +2946,9 @@ amd64_x32_init_abi (struct gdbarch_info info,
struct gdbarch *gdbarch)
tdesc = tdesc_x32;
tdep->tdesc = tdesc;

+ tdep->sp_regnum = -AMD64_RSP_REGNUM; /* %esp */
+ tdep->pc_regnum = -AMD64_RIP_REGNUM; /* %eip */
+
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..a287785 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -7671,8 +7671,8 @@ i386_gdbarch_init (struct gdbarch_info info,
struct gdbarch_list *arches)
set_gdbarch_long_double_bit (gdbarch, 96);

/* Register numbers of various important registers. */
- set_gdbarch_sp_regnum (gdbarch, I386_ESP_REGNUM); /* %esp */
- set_gdbarch_pc_regnum (gdbarch, I386_EIP_REGNUM); /* %eip */
+ tdep->sp_regnum = I386_ESP_REGNUM; /* %esp */
+ tdep->pc_regnum = I386_EIP_REGNUM; /* %eip */
set_gdbarch_ps_regnum (gdbarch, I386_EFLAGS_REGNUM); /* %eflags */
set_gdbarch_fp0_regnum (gdbarch, I386_ST0_REGNUM); /* %st(0) */

@@ -7871,6 +7871,16 @@ i386_gdbarch_init (struct gdbarch_info info,
struct gdbarch_list *arches)
else
tdep->mm0_regnum = -1;

+ /* Set up SP and PC register numbers. */
+ set_gdbarch_sp_regnum (gdbarch,
+ tdep->sp_regnum >= 0
+ ? tdep->sp_regnum
+ : tdep->eax_regnum - tdep->sp_regnum);
+ set_gdbarch_pc_regnum (gdbarch,
+ tdep->pc_regnum >= 0
+ ? tdep->pc_regnum
+ : tdep->eax_regnum - tdep->pc_regnum);
+
/* Hook in the legacy prologue-based unwinders last (fallback). */
frame_unwind_append_unwinder (gdbarch, &i386_stack_tramp_frame_unwind);
frame_unwind_append_unwinder (gdbarch, &i386_sigtramp_frame_unwind);
diff --git a/gdb/i386-tdep.h b/gdb/i386-tdep.h
index 5f233f5..99b5f42 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. If it < 0, SP register number is
+ eax_regnum - sp_regnum. */
+ int sp_regnum;
+
+ /* Register number for PC. If it < 0, PC register number is
+ eax_regnum - pc_regnum. */
+ int pc_regnum;
+
/* Number of core registers. */
int num_core_regs;