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

H.J. Lu
2012-07-03T19:15:08Z

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.

--
H.J.
---
* amd64-tdep.c (amd64_init_abi): Set sp_reg to "rsp" and pc_reg
to "rip". Don't call set_gdbarch_sp_regnum nor
set_gdbarch_pc_regnum here.
(amd64_x32_init_abi): Set sp_reg to "esp" and pc_reg to "eip".

* i386-tdep.c (i386_gdbarch_init): Set sp_reg to "esp" and
pc_reg to "eip". Set SP regnum from sp_reg and PC regnum from
pc_reg.

* i386-tdep.h (gdbarch_tdep): Add sp_reg and pc_reg.

diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
index 8ae1142..eeb21c3 100644
--- a/gdb/amd64-tdep.c
+++ b/gdb/amd64-tdep.c
@@ -2845,9 +2845,11 @@ amd64_init_abi (struct gdbarch_info info,
struct gdbarch *gdbarch)

set_gdbarch_num_regs (gdbarch, AMD64_NUM_REGS);

+ /* Names of SP and PC registers. */
+ tdep->sp_reg = "rsp";
+ tdep->pc_reg = "rip";
+
/* Register numbers of various important registers. */
- set_gdbarch_sp_regnum (gdbarch, AMD64_RSP_REGNUM); /* %rsp */
- set_gdbarch_pc_regnum (gdbarch, 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 +2948,10 @@ amd64_x32_init_abi (struct gdbarch_info info,
struct gdbarch *gdbarch)
tdesc = tdesc_x32;
tdep->tdesc = tdesc;

+ /* Names of SP and PC registers. */
+ tdep->sp_reg = "esp";
+ tdep->pc_reg = "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..67805d3 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -7610,6 +7610,7 @@ i386_gdbarch_init (struct gdbarch_info info,
struct gdbarch_list *arches)
const struct target_desc *tdesc;
int mm0_regnum;
int ymm0_regnum;
+ int num_regs, regno, sp_pc_regs;

/* If there is already a candidate, use it. */
arches = gdbarch_list_lookup_by_info (arches, &info);
@@ -7670,9 +7671,11 @@ i386_gdbarch_init (struct gdbarch_info info,
struct gdbarch_list *arches)
alignment. */
set_gdbarch_long_double_bit (gdbarch, 96);

+ /* Names of SP and PC registers. */
+ tdep->sp_reg = "esp";
+ tdep->pc_reg = "eip";
+
/* Register numbers of various important registers. */
- set_gdbarch_sp_regnum (gdbarch, I386_ESP_REGNUM); /* %esp */
- set_gdbarch_pc_regnum (gdbarch, 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 +7874,32 @@ i386_gdbarch_init (struct gdbarch_info info,
struct gdbarch_list *arches)
else
tdep->mm0_regnum = -1;

+ /* Set up SP and PC register numbers. */
+ num_regs = (gdbarch_num_regs (gdbarch)
+ + gdbarch_num_pseudo_regs (gdbarch));
+ sp_pc_regs = 0;
+ for (regno = 0; regno < num_regs; regno++)
+ {
+ const char *regname = tdesc_register_name (gdbarch, regno);
+ if (regname && regname[0] != '\0')
+ {
+ if ((sp_pc_regs & 0x1) == 0
+ && strcmp (regname, tdep->sp_reg) == 0)
+ {
+ set_gdbarch_sp_regnum (gdbarch, regno);
+ sp_pc_regs |= 0x1;
+ }
+ else if ((sp_pc_regs & 0x2) == 0
+ && strcmp (regname, tdep->pc_reg) == 0)
+ {
+ set_gdbarch_pc_regnum (gdbarch, regno);
+ sp_pc_regs |= 0x2;
+ }
+ }
+ if (sp_pc_regs == 0x3)
+ break;
+ }
+
/* 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..831f544 100644
--- a/gdb/i386-tdep.h
+++ b/gdb/i386-tdep.h
@@ -155,6 +155,12 @@ struct gdbarch_tdep
/* Number of SSE registers. */
int num_xmm_regs;

+ /* Name for SP register. */
+ const char *sp_reg;
+
+ /* Name for PC register. */
+ const char *pc_reg;
+
/* Bits of the extended control register 0 (the XFEATURE_ENABLED_MASK
register), excluding the x87 bit, which are supported by this GDB. */