[AArch64/gas] v[0-31] registers not allowed in cfi_offset?

[AArch64/gas] v[0-31] registers not allowed in cfi_offset?

[Steven Vormwald]

Are the v[0-31] registers intentionally not supported in cfi_offset?
I'm trying to figure out whether this is an oversight in gas due to
aarch64 support being relatively new (seems likely given bug 16694) or
if they are intentionally not supported and I need to stop emitting
cfi_offset with them.

Thanks,

Steven Vormwald

Re: [AArch64/gas] v[0-31] registers not allowed in cfi_offset?

[Richard Henderson]

On 08/06/2014 04:06 AM, Steven Vormwald wrote:
> Are the v[0-31] registers intentionally not supported in cfi_offset?
> I'm trying to figure out whether this is an oversight in gas due to
> aarch64 support being relatively new (seems likely given bug 16694) or
> if they are intentionally not supported and I need to stop emitting
> cfi_offset with them.

You mean by name?  Technically, only the low 64-bits is supportable in the
unwind info, i.e. d[0-31].  So I think we shouldn't allow the V registers by
name.  Or under the B, H or S names either, come to that.

But I also see that we produce invalid unwind info for the D regs:


	.cfi_startproc
foo:
	nop
	.cfi_offset x10,0
	.cfi_offset d10,0
	.cfi_endproc

00000014 00000018 00000018 FDE cie=00000000 pc=00000000..00000004
  DW_CFA_advance_loc: 4 to 00000004
  DW_CFA_offset: r10 at cfa+0
  DW_CFA_offset: r10 at cfa+0

That second opcode should be r42.


r~