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gdb: don't handle i386 k registers as pseudo registers

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I think that i386 k registers are raw registers, and therefore shouldn't
be handled in the various functions handling pseudo registers.

What tipped me off is the code in i386_pseudo_register_read_into_value:

      else if (i386_k_regnum_p (gdbarch, regnum))
	{
	  regnum -= tdep->k0_regnum;

	  /* Extract (always little endian).  */
	  status = regcache->raw_read (tdep->k0_regnum + regnum, raw_buf);

We take regnum (the pseudo register number we want to read), subtract
k0_regnum, add k0_regnum, and pass the result to raw_read.  So we would
end up calling raw_read with the same regnum as the function received
which is supposedly a pseudo register number.

Other hints are:

 - The command `maint print raw-registers` shows the k registers.
 - Printing $k0 doesn't cause i386_pseudo_register_read_into_value to be
   called.
 - There's code in i387-tdep.c to save/restore the k registers.

Remove handling of the k registers from:

 - i386_pseudo_register_read_into_value
 - i386_pseudo_register_write
 - i386_ax_pseudo_register_collect

Change-Id: Ic97956ed59af6099fef6d36a0b61464172694562
Reviewed-by: John Baldwin <jhb@FreeBSD.org>
This commit is contained in:
Simon Marchi 2023-12-01 11:27:14 -05:00
parent 1d2f86b6b7
commit c3a03de70f
1 changed files with 0 additions and 23 deletions
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23
gdb/i386-tdep.c
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@ -3464,17 +3464,6 @@ i386_pseudo_register_read_into_value (struct gdbarch *gdbarch,
memcpy (buf + size, &upper, size);
}
}
else if (i386_k_regnum_p (gdbarch, regnum))
{
regnum -= tdep->k0_regnum;
/* Extract (always little endian). */
status = regcache->raw_read (tdep->k0_regnum + regnum, raw_buf);
if (status != REG_VALID)
result_value->mark_bytes_unavailable (0, 8);
else
memcpy (buf, raw_buf, 8);
}
else if (i386_zmm_regnum_p (gdbarch, regnum))
{
regnum -= tdep->zmm0_regnum;
@ -3656,12 +3645,6 @@ i386_pseudo_register_write (struct gdbarch *gdbarch, struct regcache *regcache,
regcache->raw_write (I387_BND0R_REGNUM (tdep) + regnum, raw_buf);
}
else if (i386_k_regnum_p (gdbarch, regnum))
{
regnum -= tdep->k0_regnum;
regcache->raw_write (tdep->k0_regnum + regnum, buf);
}
else if (i386_zmm_regnum_p (gdbarch, regnum))
{
regnum -= tdep->zmm0_regnum;
@ -3758,12 +3741,6 @@ i386_ax_pseudo_register_collect (struct gdbarch *gdbarch,
ax_reg_mask (ax, I387_BND0R_REGNUM (tdep) + regnum);
return 0;
}
else if (i386_k_regnum_p (gdbarch, regnum))
{
regnum -= tdep->k0_regnum;
ax_reg_mask (ax, tdep->k0_regnum + regnum);
return 0;
}
else if (i386_zmm_regnum_p (gdbarch, regnum))
{
regnum -= tdep->zmm0_regnum;