Incorrect DecodedCallFrameTable information

[Kelvin Chung]

The following is the CIE/FDE information:

00000000 000000000000000c ffffffff CIE
  Version:               3
  Augmentation:          ""
  Code alignment factor: 1
  Data alignment factor: -4
  Return address column: 1

  DW_CFA_def_cfa_register: r2 (sp)
  DW_CFA_nop

00000010 000000000000002c 00000000 FDE cie=00000000 pc=00000000000108b8..00000000000109a0
  DW_CFA_advance_loc: 4 to 00000000000108bc
  DW_CFA_def_cfa_offset: 32
  DW_CFA_advance_loc: 12 to 00000000000108c8
  DW_CFA_offset: r9 (s1) at cfa-16
  DW_CFA_offset: r18 (s2) at cfa-24
  DW_CFA_offset: r8 (s0) at cfa-8
  DW_CFA_advance_loc1: 200 to 0000000000010990
  DW_CFA_restore: r8 (s0)
  DW_CFA_advance_loc: 4 to 0000000000010994
  DW_CFA_restore: r9 (s1)
  DW_CFA_advance_loc: 4 to 0000000000010998
  DW_CFA_restore: r18 (s2)
  DW_CFA_advance_loc: 4 to 000000000001099c
  DW_CFA_def_cfa_offset: 0
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop

and the following DecodedCallFrameTable is generated:

DecodedCallFrameTable(table=[{'pc': 67768, 'cfa': CFARule(reg=2, offset=0, expr=None)}, 
                             {'pc': 67772, 'cfa': CFARule(reg=2, offset=32, expr=None)}, 
                             {'pc': 67784, 'cfa': CFARule(reg=2, offset=32, expr=None), 
                                9: RegisterRule(OFFSET, -16), 
                                18: RegisterRule(OFFSET, -24), 
                                8: RegisterRule(OFFSET, -8)}, 
                             {'pc': 67984, 'cfa': CFARule(reg=2, offset=32, expr=None), 
                                9: RegisterRule(OFFSET, -16), 
                                18: RegisterRule(OFFSET, -24)}, 
                            {'pc': 67988, 'cfa': CFARule(reg=2, offset=32, expr=None), 
                                18: RegisterRule(OFFSET, -24)}, 
                            {'pc': 67992, 'cfa': CFARule(reg=2, offset=32, expr=None)}, 
                             {'pc': 67996, 'cfa': CFARule(reg=2, offset=0, expr=None)}], reg_order=[9, 18, 8])

we can see that the restore on reg8 is lost.

the code I used to get the DecodedCallFrameTable

def callFrameInfoExtract(filename: str):
     with open(filename, "rb") as f:
        elffile = ELFFile(f)

        if not elffile.has_dwarf_info():
            logging.debug("  file has no DWARF info")
            raise

        dwarfInfo = elffile.get_dwarf_info()
        cfiEntry = dwarfInfo.CFI_entries()
        for i in cfiEntry:
            if isinstance(i, FDE):
                print(i)
                print(i.get_decoded())
                break

This is the binary used. It is a RISC-V binary.
fft.zip