Re: x32 ABI Support (was Re: Three weeks to branching (gdb 7.5 release))

H.J. Lu
2012-06-11T13:42:50Z

On Sun, Jun 10, 2012 at 2:51 PM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
>> Date: Thu, 31 May 2012 11:18:02 -0700
>> From: "H.J. Lu" <hjl.tools@gmail.com>
>>
>> > I think this is the wrong approach for x32 support. We should
>> > break amd64_x32_init_abi into 2 parts:
>> >
>> > 1. OS specific part.  It should be private to amd64-tdep.c.
>
> There is no OS specific code in amd64-tdep.c.  Only code that
> implements the generic OS-agnistic low-level ABI.
>
>> > 2. Generic part.  It should be exported from amd64-tdep.c and can
>> > be used by all x32 OSes.
>
> Yes, and that entry point should be amd64_x32_init_abi().  That is the
> pattern that has been established, and I see no reason to deviate from
> it.  So here is the diff I suggested before again with one change: it
> moves most of the amd64 Linux support bits into its own function and
> calls that from both amd64_linux_init_abi() and
> amd64_x32_linux_init_abi().  I'm sure some of those bits are wrong for
> x32, but if you want to fix things up from that end, it is fine with
> me.  The important bit that I care about is getting the inheritance
> structure right.
>
>
> Index: amd64-linux-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/amd64-linux-tdep.c,v
> retrieving revision 1.50
> diff -u -p -r1.50 amd64-linux-tdep.c
> --- amd64-linux-tdep.c  12 May 2012 08:54:03 -0000      1.50
> +++ amd64-linux-tdep.c  10 Jun 2012 21:39:08 -0000
> @@ -1288,41 +1288,12 @@ amd64_linux_core_read_description (struc
>  }
>
>  static void
> -amd64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
> +amd64_linux_init_abi_common(struct gdbarch_info info, struct gdbarch *gdbarch)
>  {
>   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> -  const struct target_desc *tdesc = info.target_desc;
> -  struct tdesc_arch_data *tdesc_data = (void *) info.tdep_info;
> -  const struct tdesc_feature *feature;
> -  int valid_p;
> -
> -  gdb_assert (tdesc_data);
>
>   linux_init_abi (info, gdbarch);
>
> -  tdep->gregset_reg_offset = amd64_linux_gregset_reg_offset;
> -  tdep->gregset_num_regs = ARRAY_SIZE (amd64_linux_gregset_reg_offset);
> -  tdep->sizeof_gregset = 27 * 8;
> -
> -  amd64_init_abi (info, gdbarch);
> -
> -  /* Reserve a number for orig_rax.  */
> -  set_gdbarch_num_regs (gdbarch, AMD64_LINUX_NUM_REGS);
> -
> -  if (! tdesc_has_registers (tdesc))
> -    tdesc = tdesc_amd64_linux;
> -  tdep->tdesc = tdesc;
> -
> -  feature = tdesc_find_feature (tdesc, "org.gnu.gdb.i386.linux");
> -  if (feature == NULL)
> -    return;
> -
> -  valid_p = tdesc_numbered_register (feature, tdesc_data,
> -                                    AMD64_LINUX_ORIG_RAX_REGNUM,
> -                                    "orig_rax");
> -  if (!valid_p)
> -    return;
> -
>   tdep->sigtramp_p = amd64_linux_sigtramp_p;
>   tdep->sigcontext_addr = amd64_linux_sigcontext_addr;
>   tdep->sc_reg_offset = amd64_linux_sc_reg_offset;
> @@ -1330,10 +1301,6 @@ amd64_linux_init_abi (struct gdbarch_inf
>
>   tdep->xsave_xcr0_offset = I386_LINUX_XSAVE_XCR0_OFFSET;
>
> -  /* GNU/Linux uses SVR4-style shared libraries.  */
> -  set_solib_svr4_fetch_link_map_offsets
> -    (gdbarch, svr4_lp64_fetch_link_map_offsets);
> -
>   /* Add the %orig_rax register used for syscall restarting.  */
>   set_gdbarch_write_pc (gdbarch, amd64_linux_write_pc);
>
> @@ -1543,6 +1510,88 @@ amd64_linux_init_abi (struct gdbarch_inf
>
>   tdep->i386_syscall_record = amd64_linux_syscall_record;
>  }
> +
> +static void
> +amd64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
> +{
> +  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> +  const struct target_desc *tdesc = info.target_desc;
> +  struct tdesc_arch_data *tdesc_data = (void *) info.tdep_info;
> +  const struct tdesc_feature *feature;
> +  int valid_p;
> +
> +  gdb_assert (tdesc_data);
> +
> +  tdep->gregset_reg_offset = amd64_linux_gregset_reg_offset;
> +  tdep->gregset_num_regs = ARRAY_SIZE (amd64_linux_gregset_reg_offset);
> +  tdep->sizeof_gregset = 27 * 8;
> +
> +  amd64_init_abi (info, gdbarch);
> +
> +  /* Reserve a number for orig_rax.  */
> +  set_gdbarch_num_regs (gdbarch, AMD64_LINUX_NUM_REGS);
> +
> +  if (! tdesc_has_registers (tdesc))
> +    tdesc = tdesc_amd64_linux;
> +  tdep->tdesc = tdesc;
> +
> +  feature = tdesc_find_feature (tdesc, "org.gnu.gdb.i386.linux");
> +  if (feature == NULL)
> +    return;
> +
> +  valid_p = tdesc_numbered_register (feature, tdesc_data,
> +                                    AMD64_LINUX_ORIG_RAX_REGNUM,
> +                                    "orig_rax");
> +  if (!valid_p)
> +    return;
> +
> +  amd64_linux_init_abi_common (info, gdbarch);
> +
> +  /* GNU/Linux uses SVR4-style shared libraries.  */
> +  set_solib_svr4_fetch_link_map_offsets
> +    (gdbarch, svr4_lp64_fetch_link_map_offsets);
> +}
> +
> +static void
> +amd64_x32_linux_init_abi(struct gdbarch_info info, struct gdbarch *gdbarch)
> +{
> +  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> +  const struct target_desc *tdesc = info.target_desc;
> +  struct tdesc_arch_data *tdesc_data = (void *) info.tdep_info;
> +  const struct tdesc_feature *feature;
> +  int valid_p;
> +
> +  gdb_assert (tdesc_data);
> +
> +  tdep->gregset_reg_offset = amd64_linux_gregset_reg_offset;
> +  tdep->gregset_num_regs = ARRAY_SIZE (amd64_linux_gregset_reg_offset);
> +  tdep->sizeof_gregset = 27 * 8;
> +
> +  amd64_x32_init_abi (info, gdbarch);
> +
> +  /* Reserve a number for orig_rax.  */
> +  set_gdbarch_num_regs (gdbarch, AMD64_LINUX_NUM_REGS);
> +
> +  if (! tdesc_has_registers (tdesc))
> +    tdesc = tdesc_x32_linux;
> +  tdep->tdesc = tdesc;
> +
> +  feature = tdesc_find_feature (tdesc, "org.gnu.gdb.i386.linux");
> +  if (feature == NULL)
> +    return;
> +
> +  valid_p = tdesc_numbered_register (feature, tdesc_data,
> +                                    AMD64_LINUX_ORIG_RAX_REGNUM,
> +                                    "orig_rax");
> +  if (!valid_p)
> +    return;
> +
> +  amd64_linux_init_abi_common (info, gdbarch);
> +
> +  /* GNU/Linux uses SVR4-style shared libraries.  */
> +  set_solib_svr4_fetch_link_map_offsets
> +    (gdbarch, svr4_ilp32_fetch_link_map_offsets);
> +}
>
>
>  /* Provide a prototype to silence -Wmissing-prototypes.  */
> @@ -1553,6 +1602,8 @@ _initialize_amd64_linux_tdep (void)
>  {
>   gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
>                          GDB_OSABI_LINUX, amd64_linux_init_abi);
> +  gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x64_32,
> +                         GDB_OSABI_LINUX, amd64_x32_linux_init_abi);
>
>   /* Initialize the Linux target description.  */
>   initialize_tdesc_amd64_linux ();
> Index: amd64-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/amd64-tdep.c,v
> retrieving revision 1.104
> diff -u -p -r1.104 amd64-tdep.c
> --- amd64-tdep.c        14 May 2012 18:56:40 -0000      1.104
> +++ amd64-tdep.c        10 Jun 2012 21:39:09 -0000
> @@ -258,7 +258,8 @@ static const char *amd64_word_names[] =
>  static const char *amd64_dword_names[] =
>  {
>   "eax", "ebx", "ecx", "edx", "esi", "edi", "ebp", "esp",
> -  "r8d", "r9d", "r10d", "r11d", "r12d", "r13d", "r14d", "r15d"
> +  "r8d", "r9d", "r10d", "r11d", "r12d", "r13d", "r14d", "r15d",
> +  "eip"
>  };
>
>  /* Return the name of register REGNUM.  */
> @@ -2729,6 +2730,43 @@ amd64_init_abi (struct gdbarch_info info
>   set_gdbarch_stap_parse_special_token (gdbarch,
>                                        i386_stap_parse_special_token);
>  }
> +
> +
> +static struct type *
> +amd64_x32_pseudo_register_type (struct gdbarch *gdbarch, int regnum)
> +{
> +  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> +
> +  switch (regnum - tdep->eax_regnum)
> +    {
> +    case AMD64_RBP_REGNUM:     /* %ebp */
> +    case AMD64_RSP_REGNUM:     /* %esp */
> +      return builtin_type (gdbarch)->builtin_data_ptr;
> +    case AMD64_RIP_REGNUM:     /* %eip */
> +      return builtin_type (gdbarch)->builtin_func_ptr;
> +    }
> +
> +  return i386_pseudo_register_type (gdbarch, regnum);
> +}
> +
> +void
> +amd64_x32_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
> +{
> +  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> +  const struct target_desc *tdesc = info.target_desc;
> +
> +  amd64_init_abi (info, gdbarch);
> +
> +  if (! tdesc_has_registers (tdesc))
> +    tdesc = tdesc_x32;
> +  tdep->tdesc = tdesc;
> +
> +  tdep->num_dword_regs = 17;
> +  set_tdesc_pseudo_register_type (gdbarch, amd64_x32_pseudo_register_type);
> +
> +  set_gdbarch_long_bit (gdbarch, 32);
> +  set_gdbarch_ptr_bit (gdbarch, 32);
> +}
>
>  /* Provide a prototype to silence -Wmissing-prototypes.  */
>  void _initialize_amd64_tdep (void);
> Index: amd64-tdep.h
> ===================================================================
> RCS file: /cvs/src/src/gdb/amd64-tdep.h,v
> retrieving revision 1.21
> diff -u -p -r1.21 amd64-tdep.h
> --- amd64-tdep.h        4 Jan 2012 08:16:56 -0000       1.21
> +++ amd64-tdep.h        10 Jun 2012 21:39:09 -0000
> @@ -80,6 +80,8 @@ extern void amd64_displaced_step_fixup (
>                                        struct regcache *regs);
>
>  extern void amd64_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch);
> +extern void amd64_x32_init_abi (struct gdbarch_info info,
> +                               struct gdbarch *gdbarch);
>
>  /* Fill register REGNUM in REGCACHE with the appropriate
>    floating-point or SSE register value from *FXSAVE.  If REGNUM is
>
>

It works with the following patch. Can you check it in?

Thanks.

--
H.J.
---
diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index 5b04505..9cc2e30 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -2780,7 +2780,7 @@ i386_mmx_type (struct gdbarch *gdbarch)
/* Return the GDB type object for the "standard" data type of data in
register REGNUM. */

-static struct type *
+struct type *
i386_pseudo_register_type (struct gdbarch *gdbarch, int regnum)
{
if (i386_mmx_regnum_p (gdbarch, regnum))
diff --git a/gdb/i386-tdep.h b/gdb/i386-tdep.h
index f297ae7..e1f7c44 100644
--- a/gdb/i386-tdep.h
+++ b/gdb/i386-tdep.h
@@ -307,6 +315,7 @@ extern int i386_dword_regnum_p (struct gdbarch
*gdbarch, int regnum);
extern int i386_xmm_regnum_p (struct gdbarch *gdbarch, int regnum);
extern int i386_ymm_regnum_p (struct gdbarch *gdbarch, int regnum);

+extern struct type *i386_pseudo_register_type (struct gdbarch *, int);
extern const char *i386_pseudo_register_name (struct gdbarch *gdbarch,
int regnum);